Compositions – Light transmission modifying compositions – Modification caused by energy other than light
Reexamination Certificate
1999-10-15
2002-01-08
Dentz, Bernard (Department: 1625)
Compositions
Light transmission modifying compositions
Modification caused by energy other than light
C359S296000, 47, C546S005000
Reexamination Certificate
active
06337038
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to particles for a window which varies the degree of light transmission depending on presence of an electric field, and more particularly to dichronic particles which show a special directional arrangement in presence of an electric field as one of the methods to satisfy a user's desire with a specific function of regulating light transmission on the window made of those particles, when the window is used as an external decoration material for cars and buildings for varying the degree of light transmission.
There has been developed a variety of techniques on windows which has been used as external decoration material for cars and buildings with the special fuction of providing selectivity of light transmission to meet a user's demand, i.e., the so called “smart window”.
There are three methods of producing the smart window. First of all, the most commonly used method is by means of oxidation and reduction of materials. Specifically, electrolytes and materials are injected between the conductive glasses to induce oxidation and reduction reactions. When power is applied to the glass, colors of these materials are changed to regulate the degree of light transmission by controlling the amount of light to be absorbed. Another method is the directional arrangement of particular chemicals in the presence of an electric field. This method is classified into two specific methods: one using directional arrangements of liquid crystals which are made into a film and inserted into the conductive glass; and the other using directional arrangements of dichronic particles.
The aforementioned specific methods will be described in detail. In the first method of making liquid crystals into a film to be inserted between the conductive glass, when the electric field is not applied between the conductive glass, the degree of light refraction can be different at the liquid crystals and polymeric resins to cause birefringence. Therefore, light is refracted in the boundary of the liquid crystals and the macromolecules to generate a semi-transparent state. When power is applied to the semitransparent state of liquid crystals, they are arranged in parallel to the electric field. Therefore, the refractive index of the liquid crystals and that of the macromolecule resin become identical to thereby prohibit generation of birefringence and increase the degree of light transmission.
On the other hand, in the method of using the directional arrangements of dichronic particles, the particles having two directions of light transmission are dispersed between the glass to induce directional arrangements in the presence of an electric field, thereby controlling the degree of light transmission. This method has been developed by Research Frontier Co. for the first time (U.S. Pat. Nos. 4,164,365, 4,247,275, 4,407,565, 4,422,963, 4,435,047, 4,579,423, 4,616,903, 4,657,349, 5,463,491).
In principle, if the electric field is not formed at the glass, the dichronic particles irregularly move to cause diffusion and refraction of light, thereby decreasing the degree of light transmission. If the electric field is applied at the glass, the particles are arranged in a predetermined direction to readily transmit light and increase the degree of light transmission.
The particles of the smart window produced by the Research Frontier are obtained by reaction of polyiodine and an alkaloid, wherein the alkaloid series includes dihydro cinchonidine sulfate, quinine, quinine bi-sulfate (U.S. Pat. No. 4,422,963), and para 2,5 dicarboxyl acid hydroxy quinoline; and the polyiodine series includes cesium iodide, calcium iodide or a resultant produced by reacting potassium iodide and iodine. The light polarizing crystals synthesized by mixing alkaloid and polyiodine vary the amount of light to be transmitted in accordance with directions of incident light. In other words, the light absorption coefficient at one axis of the crystal particles is different from that at the other axis thereof, so that the degree of light transmission becomes different.
The directional arrangement of the particles can be manipulated to meet the user's desire by controlling the total amount of light to be transmitted through the crystals. The particles are dispersed into proper acrylate based macromolecules and phthalate or trimellitate series used as a plasticizer and injected between glass.
When power is not applied, the particles are not arranged in the solution state. Therefore, the light is not to be transmitted but to be scattered through the solution state of the particles, thereby decreasing the degree of light transmission as in the state of crystals.
When power is applied, the particles are arranged in a predetermined direction, increasing the degree of light transmission.
However, there are problems in the aforementioned method in that the transparency of the solution or film injected between glass layers is lower, that only a mechanical mixing method is used in the dispersion procedure of the particles, that it takes longer to obtain a uniform size of particles, and that the degree of light transmission is different within approximately 30% in the two cases, in absence and presence of power applied to the window which varies the degree of light transmission.
SUMMARY OF THE INVENTION
The present invention is presented to solve the aforementioned problems and it is an object of the present invention to provide a new composition to be used in producing a smart window as an external decoration material for cars and buildings, implementing the selectivity of light transmission, wherein dichronic particles of the window are arranged in predetermined directions in the presence of an electric field, to improve transparency, and the degree of light transmission in the presence of power.
It is another object of the present invention to provide a window made of particles which vary the degree of light transmission.
In order to achieve the objects of the present invention, there are provided particles for a window which varies the degree of light transmission in the presence of an electric field, wherein the particles are obtained by reacting metal complexes of transition metals with ligands containing a nitrogen atom, and polyiodines.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below. As described above, the particles of the present invention are obtained by reacting metal complexes of transition metals and ligands containing a nitrogen atom, and polyiodines. The particles are dispersed to form a solution or a film, and then injected or interposed between conductive glass to produce a window which varies the degree of light transmission in the presence of an electric field.
The particles of the present invention show physical properties as follows: first of all, the crystal particles show a difference in the degree of light transmission at both axial directions of the crystal particle; secondly, the particles are uniform in the size and less than 1 &mgr;m in dispersion; thirdly, the dispersed particles are able to remain in a homogeneous and stable whether as a solution or a film, without any modifications caused by light, reactions with other materials, and so on, even if iodine is added in the production procedures. Finally, there is an affinity between a dispersion of macromolecules with particular functional groups and the particles, even if the dispersion macromolecules are used for preventing clusteration of the particles.
At this time, the particles are the result of reacting complex chemicals and polyiodines.
In producing the particles of the present invention, a transition metal atom can be selectively taken among nickel acetate tetrahydrate, cobalt acetate tetrahydrate, copper acetate hydrate and nickel chloride hydrate as a starting material in the synthesis of complex chemicals. Picolinic acid can be chosen as a ligand because it contains functional groups of nitrogen atom and carboxylic acid to produce a com
Kim Do Sung
Lee Seung Hwa
Dentz Bernard
Korea Kumho Petrochemical Co. Ltd.
LandOfFree
Particles of a window for varying the degree of light... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Particles of a window for varying the degree of light..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Particles of a window for varying the degree of light... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2861035