[DESCRIPTION] [Invention TitIe]

ANTI-FOGGING METHOD AND GLASS AND LENS MANUFACTURED BY USING THE SAME [Technical Field]

<i> The present invention relates to an anti-fogging method and glass and lens manufactured by using the same. More particularly, the present invention relates to an anti-fogging method and glass and lens manufactured by using the same, capable of preventing the glass or lens from fogging and permanently maintaining anti-fogging effect while keeping the surface strength of a glass or a lens by filling fine crystal powder in a plurality of pores formed when the glass or lens is manufactured. [Background Art]

<2> If the temperature drops, glass or a lens of glasses is fogged up, so a person cannot see anything, causing unpleasant feeling. In addition, when a mirror is used in a bathroom, if the mirror is fogged up with the steam, the mirror does not exhibit images, so a user must pour water on the mirror. The present invention has been made to solve the above mentioned problem.

<3> Such a fogging refers to a phenomenon occurring on a solid surface when the solid surface is subject to high-temperature and high-humidity condition from low-temperature condition. That is, if the temperature of the solid surface is lower than the dew point of air, vapor is condensed on the solid surface and then is changed into small droplets. If the contact angle between the vapor and solid surface is 30 degrees or less, preferably 10 degrees or below, even if the vapor or steam contained in the air is condensed, the condensed substance forms a water film without forming separate droplets. In addition, various efforts have been pursued to provide hydrophilicity to the solid surface.

<4> Even if the glass, plastic and the lens of the glasses have superior quality, a large number of fine concave-convex sections and pores having a size less than lμm exist in the surface of the glass, the plastic and the lens of the glasses. In particular, such a fine pore can be naturally formed

due to a bonding structure of components of the glass, the plastic and the lens of the glasses, or can be inevitably formed during the manufacturing process.

<5> Even if the surface of the glass, plastic and lens of the glasses has the hydrophilicity, as time goes by, contaminants such as organic particles are adsorbed on the surface, lowering the hydrophilicity, and the contaminants serve as a nucleus for water droplets.

<6> In particular, the contaminants adsorbed in the pores are more strongly adsorbed by Van der Waals forces with respect to a wall of the pore, so that the contaminants are not easily removed. Accordingly, once the contaminants are adsorbed, the hydrophilicity is continuously lowered.

<7> The anti-fogging method, which has been currently used, is mainly classified into three types of method.

<8> According to a first method, silica sol or a titanium dioxide having superior adhesion, transparency and superior hydrophilicity is coated on an object. An UV-coating using UV curing to increase the strength of the object belongs to the first method. However, a film made through the above method has a limitation in that strength of the film is less than 3H. In addition, even if the film has a substantially small thickness, the coated material may have various refractive indexes, so multiple effects providing various visual effects may disappear, and the industrial applicability of the product is lowered.

<9> According to a second method, the surface is treated with plasma. The method for modifying the surface of the object using plasma including oxygen, hydrogen, nitrogen, helium and argon is very effective, however, if a thickness or a depth of a material treated by plasma is increased, the quality of the object is changed. Therefore, the film is provided only in an extremely small thickness. As a result, the modified film has a weak strength, so the treatment effect by the plasma is insufficient. In this case, the anti-fogging effect easily disappears with one rubbing action. <io> According to a third method, an electric circuit is formed on a film

using conductive material. For example, the third method is realized by embedding a wire in a window glass of a vehicle and then applying electricity to the wire to emit heat. The third method has disadvantages in that the application is limited and the cost on equipment and maintenance is increased. Accordingly, the third method is basically different from a method that enables glass to have the anti-fogging function.

<ii> In addition, according to methods for forming an organic coating layer having a hydrophilicity on a surface of the object covered with steam, si lane compounds are coated (Korean Unexamined Patent Publication No. 2002-042787, U.S. Patent Nos. 6,040,053 and 4,625,031, and Japanese Unexamined Patent Publication No. 2001-337211), polyurethane compounds are coated (Korean Unexamined Patent Publication No. 2002-010251, U.S. Patent Nos. 4,789,720; 4,743,673; 4,451,635; and 3,975,350), a cleaning solution and a coating solution including hydrophilic organic substance to surfactant are coated (Korean Unexamined Patent Publication No. 2000-073475, 1999-083774 and 1994- 024028, U.S. Patent Nos. 4,615,738; 5,716,921; 5,254,284; 4,374,745; 5,846,650; and 6,384,120, Japanese Unexamined Patent Publication Nos. 1999- 137389 and 2001-233979), polyether blockamide compounds are coated (Korean Unexamined Patent Publication No. 1997-706346), alpha olefin is coated (Korean Unexamined Patent Publication No. 1997-033826), poly-vinyl alcohol is coated (U.S. Patent No. 4,127,682), ester compounds are coated (U.S. patent Nos. 6,046,254 and 4,486,552 and Japanese Patent Nos. 4180942 and 10148705), poly ethylene oxy alcohol (U.K. Patent No. 767, 955), synthetic resin film is coated (European Patent Nos. 0933400 and 0931805, U.S. Patent Nos. 5,567,533 and 5,520,764, and Japanese Patent No. 11335486), organic silicon compounds are coated (Japanese Unexamined Patent No. 2000-239655) and organic or inorganic mixture is coated (Japanese Patent No. 9113704), in which most of the coating is realized by drying off a wet-coating or by attaching an organic laminate.

<12> The hydrophilicity of various organic substances described above is generally degraded with age, or the coating layer including the organic

substance hardly forms a uniform thin film. In addition, when the organic substances are used to realize the anti-fogging effect or applied as the anti-fogging layer, the anti-fogging capability is easily lowered and durability of the coating layer is degraded in such a manner that the transparency of the coating layer is lowered or the strength of the coating layer is reduced. In addition, the coating layer cannot be applied to various optical devices.

<i3> In addition to the anti-fogging methods described above, methods for coating a hydrophilic polymerized layer using plasma are disclosed in Korean Unexamined Patent Publication Nos. 2001-013160, 2001-013156, 1999-047370 and 1999-041210 and a scientific journal ("Plating and Surface Finishing" p52, October, 1994). According to the above methods, DC plasma or radio frequency plasma is generated in a vacuum atmosphere containing hydrocarbon and nitrogen, and then a position of a surface of a basis material existing in the plasma and current are adjusted, thereby coating a hydrophilic polymerized layer (having compounds including one selected from the group consisting of carbon, hydrogen, nitrogen and oxygen) on the surface of the object. In this case, the anti-fogging capability is determined by the hydrophilicity of the polymerized layer formed under a specific process condition,

<i4> That is, the thickness and the hydrophilicity of the polymerized layer vary depending on a shape and a position of the surface of the basis material, and a discharge condition, causing a difficulty in ensuring uniformity of the polymerized layer. In addition, the basis material is subject to thermal deformation by the heat treatment, which is performed for the plasma heating and the stabilization of the polymerized layer.

<i5> In addition, most of the anti-fogging methods described above realize the anti-fogging effect by forming the coating layer and are completely different from the present invention, which realizes the anti-fogging effect by filling transparent crystal powder in pores. [Disclosure]

[Technical Problem]

<16> The present invention has been made to solve the above problem occurring in the prior art, and an object of the present invention is to provide an anti-fogging method, capable of maintaining the anti-fogging effect for a long time by filling fine crystal powder in pores instead of forming a coating film.

<i7> In addition, another object of the present invention is to provide an anti-fogging method, in which a coating film is not formed, so the surface strength of glass or lens is maintained without exerting influence or variation upon an original object.

<18> Still another object of the present invention is to provide an anti- fogging method, which can be achieved through easy processes and provide eco- friendly characteristic, thereby improving economic efficiency and productivity. [Technical Solution]

<i9> The foregoing and and/or other aspects of the present invention are achieved by providing an anti-fogging method for infiltrating crystal particles into a plurality of pores without forming a film on a surface of glass, plastic or lens and crystal particles.

<20> The method includes the steps of forming fine particles by pulverizing transparent crystal into a size of lOnm or below, manufacturing crystal suspension by mixing the pulverized fine particles with washing water; heating the crystal suspension, introducing the crystal suspension into the pores by dipping an objecting including the glass, the plastic or the lens into the crystal suspension and then moving the object up and down or left and right, and drying off the object by taking out of the suspension.

<2i> In the step of manufacturing the suspension, the fine particles are mixed with the washing water and then stirred such that the suspension has a concentration of 12%.

<22> The step of manufacturing the suspension includes adding of 0.1 to 1% of surfactant to the washing water and stirring of the washing water.

<23> The surfactant includes silicon based polyethylene oleyl or non-silicon based anion sodium dioctylsuccinate. [Advantageous Effects]

<24> As described above, according to a product manufactured by the anti- fogging method of the present invention, a coating film is not formed, so that the surface strength of an original object is maintained without exerting influence or variation upon the original object, and the anti- fogging effect can be permanently maintained.

<25> In addition, the anti-fogging method according to the present invention can be performed through substantially simple and eco-friendly manufacturing facilities. In addition, the anti-fogging method according to the present invention can enhance economic efficiency and productivity and achieve mass production with less labor force. [Description of Drawings]

<26> FIG. 1 shows pictures of a glass, which are taken before and after an anti-fogging method according to the present invention has been performed, and then are magnified hundred thousand times by an electron-microscope;

<27> FIG. 2 shows pictures of a multi-lens, which are taken before and after the anti-fogging method according to the present invention has been performed and then are magnified hundred thousand times by the electron-microscope; and

<28> FIG. 3 is a schematic view showing an object, in which the filling of crystal power is completed according to the anti-fogging method of the present invention. [Best Mode]

<29> While trying to find out a method for preventing fogging, applicant of the present invention has considered the fact that glasses made of crystal lens maintain the low temperature in summer but are nearly free of fogging in winter. In this regard, an anti-fogging method of the present invention is made. In the anti-fogging method, fine Siθ2 or transparent crystal particles, which are manufactured into a size of about IOnm through a pulverizing or a precipitation separation, are infiltrated into pores sporadic on a surface of

the glass, plastic and lens of glasses and are fixed to the pores such that the hydrophilicity is revealed due to the particles, thereby realizing the anti-fogging effect.

<30> That is, if the fine pores formed in the glass, plastic, lens of the glasses are filled with transparent crystal or Siθ2 particles that are finer than the pores, and then the transparent crystal and S1O2 particles are fixed to the pores, a hydrophilic area of the surface of the object is increased by several times, so that hydrophilicity is improved. In addition, contaminants such as organic particles are adsorbed only on the surface of the glass, plastic and the lens of the glasses, so the contaminants are easily removed. The particles fixed in the pores remain even if the surface of the object is cleaned or washed, so that the hydrophilicity can be maintained for a long time.

<3i> In addition, according to the anti-fogging method of the present invention, the fine pores existing in the surface are filled with the transparent crystal particles or SiC>2 particles, so the transparency of the lens of the glasses is improved. <32> Hereinafter, the anti-fogging method according to the present invention will be described in detail with reference to accompanying drawings. <33> The anti-fogging method according to the present invention is as follows. <34> (1) Fine particles are formed by pulverizing transparent crystal into a size of lOnm or less. <35> (2) A crystal suspension having a concentration of about 12% is formed by using the pulverized fine particles. <36> If the crystal suspension has a concentration less than 12%, the amount of crystal is so little that the crystal powder can not be infiltrated into the pores. If the crystal suspension has a concentration above 12%, the amount of crystal is excessive so that the crystal powder can not be properly infiltrated into the pores.

<37> The crystal suspension is manufactured by mixing the fine crystal particles with washing water and then stirring a mixture of the crystal particles and washing water using a stirrer for a few minutes. In addition, surfactant is added to the crystal suspension by a ratio of about 0.1 to 1% relative to the washing water, and then the mixture is stirred again for a few minutes.

<38> The surfactant preferably includes silicon based polyethylene oleyl or non-silicon based anion sodium dioctylsuccinate.

<39> Nano-particles do not need the surfactant, but the surfactant is preferably used to allow the fine crystal particles to be easily filtrated into the pores.

<40> (3) The object including the glass, plastic and lens is dipped into the crystal suspension and then is moved up and down or left and right.

<41> As described above, as the object is moved up and down or left and right in the crystal suspension, the crystal suspension can be uniformly introduced into the pores.

<42> In this case, the temperature of the crystal suspension, the infiltration time and the movement frequency of the object are changed depending on a size or a thickness of the object. The optimum range of the temperature of the crystal suspension, the infiltration time and the movement frequency is described below in Table 1.

<43> [Table 1] <44>

<45> (4) The object is taken out of the suspension and is dried. <46> The drying process can be performed by drying the object in a state

that the external contaminants are prevented from being introduced into a drying room. Otherwise, the drying process can be performed using air in a natural circumference.

<47> In the drying process, the transparent crystal fine particles infiltrated into the pores formed on the surface of the glass, plastic and lens are combined to each other to form a larger particle. Otherwise, the fine crystal particles are combined to a wall of the pores and are fixed to the pores.

<48> A reactor, in which the internal pressure is kept within a range of 650 to 860mmHg (corresponding to about 1 atmosphere) depending on the shape of the object, is used to promote the infiltration of the object and reduce the infiltration time to a few hours.

<49> The hydrophilic substance includes not only SiO ₂ , but also TiO ₂ , BaTiθ3,

TaTiO ₃ , LiNbOs, KNbO ₃ , and Bi ₂ GeO ₂₀ . Some of these hydrophilic substances shows transparency and hydrophilicity, but if a number of hydrophilic particles are collected and overlapped, the refractive index is severely distorted and the transparency is lowered, causing a problem in the hydrophilicity.

<50> Hereinafter, an embodiment of the anti-fogging method according to the present invention will be described.

<5i> (Embodiment)

<52> The crystal powder (SiO ₂ ) is prepared by pulverizing crystal into a size of IOnm, 1.2g of the pulverized crystal powder is mixed with lOOg of water, and then a mixture of the crystal powder and water is stirred for 10 minutes by using a high speed stirrer. After that, 0.6g of surfactant (silicon based polyethylene oleyl) is additionally input into the mixture, and the mixture is stirred again for 3 minutes. Then, large particles, which are precipitated while the mixture is kept stationary for 8 hours, are removed, so that the suspension is reorganized. The suspension is heated up to the temperature of 58° C to 62 ° C , and then a multi-lens is moved up and down in the suspension for 24 hours such that the multi-lens is impregnated with

suspension. After the impregnation of the multi-lens has been completed, the object is dried using the air, so that a product is manufactured.

<53> FIG. 1 shows pictures of a glass, which are taken before and after an anti-fogging method according to the present invention has been performed and then are magnified hundred thousand times by an electron-microscope, and FIG. 2 shows pictures of a multi-lens, which are taken before and after the anti- fogging method according to the present invention has been performed, and then are magnified hundred thousand times by the electron-microscope.

<54> As shown in FIGS. 1 and 2, a plurality of pores are seen in the picture taken before the anti-fogging method is performed. However, after the anti- fogging method is performed, the pores are filled with crystal powder and are not seen in the picture.

<55> FIG. 3 is a schematic view showing an object, in which the filling of crystal powder is completed according to the anti-fogging method of the present invention.

<56> As shown in FIG. 3, if the anti-fogging method according to the present invention is completed, the fine crystal particles 2 having a size of lOnm or less are filled in the pores 3 formed on the surface of the object 1 such as glass, plastic or lens.

<57> Different from the related art requiring a coating or a coating film, according to the present invention, pores are filled with crystal powder, so the anti-fogging effect can be maintained permanently. In the related art, if the coating film is delaminated or damaged, the anti-fogging effect also disappears. However, according to the present invention, the problem occurring in the related art is solved.

<58> Although few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and sprit of the invention, the scope of which is defined in the claims and their equivalents.