TW201351011A - Optical valve and its manufacturing process - Google Patents

Abstract

The present invention provides an optical valve (100) comprising first and second flat float-glass sheets (1, 2) sealed by a seal (7), first and second electrodes (3, 4), and an SPD system (5) having a thickness E of 100 μ m or less and incorporating spacers (6). The thickness A1, A2 of each of the first and second glass sheets is 6.5 mm or less and each of the internal faces has a dioptric defect rating, expressed in millidioptres, lower than or equal to E/3 or 2E/3 depending on the luminous transmission TL. The invention also relates to the process for manufacturing such an optical valve.

Description

Light valve and method of manufacturing same

The present invention relates to the field of electrically controllable inlaid glass units having variable optical properties, and more particularly to a light valve comprising suspended particles between two transparent electrode support fixtures, the orientation of which is by applying an alternating electric field or The magnetic field is modified such that the light valve is reversibly alternated between a substantially opaque state (the closed state) and a more transparent state (the open state).

The light valve system is more precisely referred to as an optical SPD valve (SPD can be substituted for "suspended particle device") and has been developed in particular by the research frontier (Research Frontiers ^® ). In the closed state, the valve has a rather significant color (blue, black, gray, etc.) and is relatively opaque, and in the open state, the valve is (more) transparent and possibly Slightly colored.

For example by thin-film light valves ^® sold by the company Hitachi Chemicals constituted by the two plastic films, the two plastic sheets made of polyethylene terephthalate (PET) by the SPD system is configured with On the indium tin oxide (ITO) electrode thereon, the SPD system takes the form of a layer made of a polymer matrix-holding microparticles containing suspended microdroplets, typically having a thickness of 50 to 130 microns. This SPD film which can be used for 3D roll products is made by rolling a PET film between two rolls. To increase rigidity and durability, the PET sheet can be bonded to the glass sheet by a "hot melt" resin or interposer such as an ethylene vinyl acetate (EVA) layer.

As regards document EP 0 766 121, a method for producing such a light valve is provided in Example 1 (b), comprising a microdroplet matrix between two glass sheets, wherein the liquid component is applied to the TCO with a tie rod A first glass sheet of a layer (TCO can be substituted with a transparent conductive oxide) is crosslinked and then the second glass sheet is loaded.

As regards document WO 94/11722, which provides a method for manufacturing such a light valve in Example 27, the light valve comprises a microdroplet matrix between two glass sheets, wherein the liquid component is applied to an ITO layer A first piece of glass; the second piece of glass is placed on top and the component is then crosslinked.

Furthermore, there is another SPD system configuration that does not employ a polymer matrix which is then completely filled with space between two glass sheets with ITO.

Its manufacture is described, for example, in a number of documents: - in WO 2004/061517 (Fig. 1), the suspension is inserted between glass sheets separated by a peripheral spacer fixed to the glass sheet, and the light The valve is then sealed; or - in WO 95/32540, a seal made of a polypropylene resin crosslinked under ultraviolet (UV) is used, the seal comprising glass a peripheral spacer formed to maintain the glass sheets at a constant distance of up to 50 microns, the closed interior space being used to hold the suspended matter filled in the opposite corners via the tube attached to the sealing portion; or even - in FR 2 147 217, the peripheral seal between the glass sheets surrounds a liquid suspension containing hard plastic beads which keep the glass sheets separated by a constant distance, the suspension system This tube is then sealed by injection through a filling tube.

The optical performance and reliability of these light valves using a fluid or microdroplet substrate SPD system between two glass sheets can be improved. This manufacturing method can be improved, especially in order to more depending on the industrial scale.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light valve comprising an SPD system between two glass sheets which not only has a simple design, but also provides a satisfactory optical performance while providing an industrial requirement (simple, Yield, flexibility, etc.) Compatible manufacturing methods.

For this purpose, the invention first provides a light valve comprising: - first and second float glass sheets sealed by a seal on the periphery of the opposing major faces, referred to as inner faces, the seal The portion is made of a given sealant which is preferably organic in nature; - on the major face of the first glass sheet, preferably the inner face rather than the outer face, the first electrode is comprised of a transparent conductive layer ( Made of a plurality of layers or a single layer; on the main surface of the second glass sheet, preferably the inner surface instead of the outer surface, the second electrode is made of a transparent conductive layer (multilayer or single layer) - the first and second electrodes are provided with power supply leads; and - between the inner faces (selectively directly between the inner faces), referred to as the SPD system, including suspension in a suspension medium Micron- or sub-micron-sized particles selectively (and preferably) in the form of (micro) droplets dispersed in a polymer matrix that is preferably crosslinked, the SPD system (forming a layer) and Into the spacer and having a given thickness E - in the matrix, or in the medium without the matrix, the thickness A1 of the first glass sheet is less than or equal to 6.5 mm or even 5.5 mm; the thickness A2 of the second glass sheet (preferably equal to A1) is less than or equal to 6.5 mm or even 5.5 mm, when the light valve has less than 5% or even 3% or more The first and second inner faces (preferably coated with the first and second electrodes) are less, especially 0.5 to 1.5% of the light transmittance T _L in no power (in the off state) The refractive index indicator value expressed in milli-refractance is E/3 or less, where the thickness E of the SPD system is expressed in microns, and the E is 100 microns or less, or even 90 microns or less. Or 70 microns or less; or when the light valve has a light transmittance T _{L of} 5% to 15% powerless (off state), the first and second inner faces (preferably the first and Each of the second electrode coatings has a refractive index indicator expressed in milli-degrees of light, which is 2E/3 or less, where the thickness E of the SPD system is expressed in microns, and the E is 50 microns or more. Less, or even 35 microns or less.

Especially when the selected glass sheet is thin and/or the thickness of the SPD system is very small, the applicant has found the quality of the glass sheets and the The relationship between the optical properties of a light valve.

Through the light valve for comparison, Figure 1 shows a light valve assembly having two commercially available glass sheets 1, 2 having a thickness of, for example, 2.1 mm, coated with electrodes 3, 4 and containing 90 microns thick. The outer faces 12, 22 and the inner faces 11', 21' of the SPD system 5 are suspended. The inner faces 11', 21' (also the electrode surfaces 31, 41) contain planar defects; the thickness E of the system fluctuates, and these fluctuations take the form of localized undulations.

In this off state (the state in which the rendering is excessive), the light transmittance _TL closely related to the thickness E is therefore non-uniform. The quality of the product is therefore unacceptable because the darker areas can be visually observed, especially for products (building facades, car mosaics, outdoor living spaces, etc.) where natural light passes directly through the first Glass piece (face 1).

As such, the Applicant has demonstrated that the acceptable variation in T _L for light valves is small, up to 5%. This measurement of the variation in T _L is performed, for example, by "cutting" the light valve over most or even all of the area of the light valve, such as by cutting 40 cm by 80 cm, or borrowing Sampling by execution statistics.

In fact, in order to ensure good optical uniformity, the refractive defects (whether or not coated) in the glass sheets must be adequately limited and controlled.

The glass sheet according to the invention is guaranteed to have a thickness E which is sufficiently uniform over its entire area and thus exhibits little variation in optical properties. This avoids the high amount of chips of the light valve and thus improves its credibility.

The meaning of the expression "refractive defect" and a measurement method will be defined below.

The profile of the inner face of each piece of glass in question (whether or not coated) can be described by y(x), where x represents the position on the inner face. The variation in this profile can be characterized by the optical power POR in the reflection, which is defined by the relationship:

The variation in y(x) is due to two effects: - undulations in the glass sheet; and - thickness defects (non-parallelism on both sides of the glass sheet).

For y(x) expressed in meters, this number is expressed in terms of refracting power (m ^-1 ).

If the second derivative y"(x) is zero, it means that the inner surface of the glass sheet is completely flat; if the second derivative is lower than 0, it means that the inner surface of the glass sheet is concave, and if The second derivative is higher than 0, which means that the inner surface of the glass sheet is convex.

The method for measuring the planarity y(x) of the inner face of the glass sheet is a non-contact optical measuring method in which the contrast of each point in a so-called radiographic image is analyzed by the radiographic image Obtained by reflecting a uniform light source from the inner surface of the glass.

The undetectable outer side of the glass sheet is wetted by a liquid having a refractive index close to the glass to suppress any reflection of the light on the surface and to retain only the image of the inner surface of the direct illumination.

This planarity is thus measured every millimeter above the illuminated surface of the inner face. Each point is quantified by the physical unit of optical power, that is, at a minimum Luminosity (mdt = refractive index / 1000), similar to converging and diverging lenses.

This final planarity is quantified by the refractive defect indication value corresponding to the standard deviation σ of all such measurements. This indication value expressed in milli-defractance (mdt) perfectly describes the planarity of the measured surface. This indication value increases as the planarity decreases.

For a given refractive defect indication value, the amplitude of the variation in y(x) is also dependent on the periodicity or pitch.

As an example, for a sinusoidal profile y(x) with a pitch of 30 mm, a 10 mdt refractive defect corresponds to a profile variation of about ± 0.20 microns. In this worst case scenario, the variation in the space separating the components of the two glass sheets (and therefore the two variations in thickness E) is then doubled, equal to about ± 0.40 microns. For a 15 mm pitch defect, the same 10 mdt refractive defect corresponds to a ±0.05 micron distribution change, and in this worst case case, the variation in the thickness E is therefore ±0.10 microns.

The pitch of the refractive defects in the float glass sheet ranges from a few millimeters to several tens of millimeters. Since the system is closely related to the uniformity of the thickness E, the uniformity of the light transmittance of the off state is the set of all refractive defects at all pitches. Floating defects (undulations) are generally major defects with a period of about p = 30 mm.

The uniformity of the light transmittance of the off state is also dependent on the average thickness E. The greater the thickness E, the more variations in the thickness of the glass can be tolerated. According to the invention, this is why the indication value is established as a function of the average thickness.

Finally, the lower the light transmittance, the greater the effect of the refractive defect. According to the invention, this is why the indication value is also a function of the off state T _L .

Float glass refractive defects are primarily related to the operating rate of the glass (the output of the line). The higher the operating rate of the glass, the greater the refractive defects. For a given capacity (or tonnage per day) and a given untreated glass sheet width, the glass operating rate is inversely proportional to the thickness A of the glass sheet. Thus, the thinner the glass sheet, the higher the glass run rate and the greater the refractive defects.

As such, it is not possible to arbitrarily choose a thickness because the refractive quality of the glass determines the thickness at which the glass can be used. The present invention allows a glass sheet to be thinner than 6 mm to be selected while ensuring the quality of the final product. For example, the present invention allows the minimum possible thickness to be used while ensuring the optical quality of the final product. For example, it is possible to select glass sheets having a thickness of 2 mm, provided that the sheets are produced with a sufficiently slow output to ensure limited refractive defects.

Moreover, even with a 6 mm thick piece of glass, if the tonnage is too high, such as 2000 tons / day, its refractive defects will be too serious.

Naturally, for the sake of simplicity and cost, it is preferred to select a suitable float glass sheet rather than having to smooth any of the glass sheets obtained by another manufacturing method (polishing, etc.).

Furthermore, the present invention allows the light valve to be produced in a custom size.

Current films in fixed size, when they are foreseeable to provide a glass reinforcement, may require cutting them, thereby resulting in an expensive loss of active SPD material.

The use of the spacers distributed in the SPD system layer, in particular in the microdroplet matrix, is primarily used to set the nominal thickness E.

The spacers are made of a non-conductive material. Preferably, the spacers are made of transparent plastic or even glass. For example, a spacer made of polymethyl methacrylate (PMMA) will be selected. The spacers are for example in the form of perimeter or elliptical beads.

The spacer content preferably ranges from 0.1 to 1% by weight of the SPD system, and is preferably 0.5% or less.

The present invention thus provides a method for increasing the plausibility of a light valve having an SPD system between two glass sheets for a preset SPD system thickness E (set by the spacers) and a preset T _L off state level, the method comprising using a float glass sheet having a refractive index indicator value lower than or equal to E/3 (low T _L ) or 2E/3 (higher T _L ), provided that the thickness A1 is Smaller than 6.5 mm.

Further, if possible, it is preferred to select a float glass sheet obtained with an output of more than 500 tons per day, especially having an untreated glass width of more than 3 meters.

Alternatively, the present invention provides a method for increasing the reliability of a light valve having an SPD system between two glass sheets for a float glass sheet of a given thickness A1 that is smaller than 6.5 mm. The method includes measuring its refractive defect indication value σ, and using an SPD system of thickness E, which is less than or equal to a maximum value of 3σ (low T _L ) or 3σ/2 (higher T _L ), depending on the off state The T _L level is determined.

Moreover, if possible, it is better to choose one to be higher than 500 tons / The glass sheets obtained from the output of the day have, in particular, an untreated glass width of more than 3 meters.

In order to reduce the size and weight, in particular, the thickness A1 of the first glass sheet and preferably the thickness A2 of the second glass sheet may be 4.5 mm or less, or even 3.5 mm or less, and preferably 1.6 ±. 0.2 mm or more.

In particular, thicknesses of 2.1 ± 0.2 mm, 3 ± 0.2 mm and 4 ± 0.2 mm will be selected, the thickness being a conventional thickness, especially for use in a production facility on a floating glass line having a capacity of at least 500 tons per day. The obtained glass sheet is especially used for glass sheets having a width of at least 3 meters.

In the present invention, the range of parameters referred to as "between limits A and B" includes the values A and B.

In a preferred embodiment, when the light transmittance T _L is less than 5%, even less than 3%, and especially from 0.5 to 1.5%: - for thickness A1 between 5.5 mm and 6.5 mm It is preferably used for a thickness A2 between 5.5 mm and 6.5 mm, especially 6 ± 0.2 mm, which is 20 microns or less; - for thicknesses A1 between 4.5 mm and 5.4 mm, and preferably For thicknesses A2 between 4.5 mm and 5.4 mm, especially 5 ± 0.2 mm, the thickness E is 30 microns or less; - for thicknesses A1 between 3.5 mm and 4.4 mm, and preferably for use in a thickness A2 between 3.5 mm and 4.4 mm, in particular 4 ± 0.2 mm, the thickness E is 35 microns or less; - for thicknesses A1 between 2.5 mm and 3.4 mm and preferably for 2.5 mm and Between 3.4 mm thickness A2, especially 3 ± 0.2 mm, the thickness E is 50 microns or less; - for thickness 1.9 between 1.9 mm and 2.4 mm, and preferably between 1.9 mm and 2.4 mm Thickness A2, especially 2.1 ± 0.2 mm, which is 90 microns or less, even 70 microns or less, or even 50 microns or less; and - for 1.3 mm and 1.8 The thickness A1 between the meters is preferably used for a thickness A2 between 1.3 mm and 1.8 mm, especially 1.6 ± 0.2 mm, which is 100 microns or less, even 70 microns or less, or even 50 microns. Or less.

In a preferred embodiment, when the light transmittance T _L is from 5% to 15%, especially from 8 to 12%: - for thickness A1 between 5.5 mm and 6.5 mm, and preferably used For a thickness A2 between 5.5 mm and 6.5 mm, the thickness E is 10 microns or less; - for a thickness A1 between 4.5 mm and 5.4 mm and preferably for use between 4.5 mm and 5.4 mm Thickness A2, the thickness E is 15 microns or less; - for thickness A1 between 3.5 mm and 4.4 mm, and preferably for thickness A2 between 3.5 mm and 4.4 mm, the thickness E is 35 microns Or less; - for thickness A1 between 2.5 mm and 3.4 mm and preferably for thickness A2 between 2.5 mm and 3.4 mm, the thickness E is 25 microns or less; - for use at 1.9 The thickness A1 between mm and 2.4 mm is preferably used for a thickness A2 between 1.9 mm and 2.4 mm, which is 45 microns or less; and - for thickness A1 between 1.3 mm and 1.8 mm Preferably, it is used for a thickness A2 between 1.3 mm and 1.8 mm, especially 1.6 ± 0.2 mm, and the thickness E is 50 microns or less.

Preferably, none of the glass sheets according to the present invention have a (blocking) aperture in its major face, the aperture being substantially used for injecting between glass sheets previously sealed by a seal SPD system.

In the prior art light valve of the microdroplet type, the SPD system is not sealed and, furthermore, the substrate extends as far as the edge. As such, the seal according to the present invention protects the SPD system including microdroplets.

Furthermore, the seal has a given width L and is preferably interruptable in its width by a plurality of splits, each split defining a lateral seal end and for each split, an additional sealant A bridge is formed between the lateral ends of the seal, the bridge being made, in particular, of the same material as the sealant, thus ensuring continuity of the material.

In the prior art suspension type light valve, the seal is continuous or incorporated into a tubular member used in a complicated manufacturing method.

Preferably, the sealing portion is free of spacers and/or mechanisms for injecting the SPD system, particularly the SPD system in the suspension, into the space surrounded by the sealing portion.

According to the present invention, the optical performance is also improved by interrupting the seal of the light valve by the slits, supplemented by an additional sealing step. In the closed state, in particular in the edge region, the SPD system is evenly distributed by participating.

According to the invention, the use of such splits - supplemented by an additional sealing step - is an invention in itself. However, in a preferred embodiment, it is coupled to a glass sheet, such as defined above, having a finite thickness A1, A2 and a limited refractive index value.

The seal may be at least two slits (or at least two of the slits) facing the first edge of the light valve and at least facing the second edge of the light valve The other slits (or at least two of the other slits) are interrupted, the second edge being opposite the first edge.

The seal and/or the additional sealant may be organic in nature, such as made from an epoxy resin.

Preferably, each of the first and second electrode coated glass sheets has a light transmission of at least 70%.

One or both of the glass sheets may be transparent, particularly transparent or even colored.

Preferably, the float glass sheets are not bent and/or heat treated, and preferably, they are not subjected to the treatment of the surface for constructing their inner faces.

One of various functional elements: a colored film, a low E layer, etc. can be applied to the outside of one or both of the glass sheets.

For example, the first or second electrode, particularly on the inner face, may itself be a low E layer (a layer comprising silver, etc.), such as described in U.S. Patent 5,325,220.

The microparticles can be of any shape or of any natural, and any known size. They may be microparticles of colloidal size (1 micron or less) or polyhalide or non-polyhalide microparticles having a maximum size of 0.3 micron or less, preferably 0.2 micron or less, in order to limit the diffusion of light.

Widely variable inorganic and organic microparticles are known, especially mica, aluminum, graphite, metal halides and perhalides, and alkaloid particles.

The particles used may be in the form of needles, rods, rods or in the form of thin snow flakes.

Depending on the desired optical properties, the concentration of the particles can be adjusted (especially depending on how effective they are) and/or their dimensions can be adjusted as a function of the thickness E.

The SPD system can include an ultraviolet agent, as is conventionally used in the prior art.

The suspending medium can contain a miscible polymer.

The suspension may also include a stabilizing polymer dissolved in the suspending medium to prevent coagulation of the particles.

Suspended SPD systems are described in the aforementioned prior art patents. Further, other examples of the suspension type SPD system are described in the patents US 4 247 175, US 4 407 565, US 4 772 103, US 5 409 734, US 5 461 506, US 5 463 492 and US 6 936 133.

SPD systems with a polymer matrix containing droplets (vulcanized, crosslinked) prefer a simple suspension. An example of such a droplet-containing SPD system is described in the patents US 5 463 491, US 5 463 492, US 7 361 252, US 6,301,040, US 6,416,827, US 6,900, 923.

The T _L obtained when the light valve is opened can be adjusted as desired.

The supplied (AC) power can be varied.

Each float glass sheet can be of any shape after cutting: - straight edges: rectangles, squares, more generally polygonal, etc.; or - Bent edges: oblate, round, elliptical, etc., for example for curved (building or car) windows.

Preferably, the electrode (many) layer on the inner face of the associated glass sheet has no noticeable effect on the refractive defects. Thus, if a "naked" float glass sheet is available, the glass sheet coated with the electrode layer will also be useful. The electrode can be a single layer (TCO, etc.) or multiple layers.

Preferably, the electrode positioned on the inner face of the glass sheet can have a given (thin) functional (protective, etc.) conductive or isolated (meteorite, etc.) layer as its final layer (directly with the SPD system) Contact) without affecting the defect indication value.

Naturally, the SPD system can extend substantially over the entire glass surface (except for the side) or over (at least) a smaller area. The SPD system can be discontinuous and split into many segments (eg, pixels).

Light valves according to the present invention can be used in buildings, on land-based, air-based, or water-based operations (between two compartments, in taxis, etc.) or externally Earth, especially: - in the curtain wall; - as an internal partition (between two rooms or in a space); - as a glass door, window, ceiling, or roofing component (sunroof, etc.); - glass-filled part of urban public works (bus shelter, etc.), external partition, etc.; and / or - as a Observe holes or curved windows, especially in vehicles (aircraft, boats, etc.).

Naturally, the light valve according to the invention can form all or part of a partition or another type of window (a louver, etc.), a majority of the inlaid glass unit (plus another reflective glass).

One or the other of the glass sheets may be laminated if desired.

The invention also relates to a method for manufacturing a light valve, preferably a valve such as that defined above (and thus having a selected glass sheet depending on E), comprising: - first and second glass (most a float glass sheet, which is sealed by a seal on the periphery of the main face, which is referred to as the inner face, which is made of a given, preferably essentially organic, sealant; a first electrode formed by a transparent conductive (single or multiple) layer on the inner surface of the first glass sheet called the first inner surface; - a second electrode, which is particularly transparent, electrically conductive (single or a plurality of layers formed on an inner face of a second glass sheet referred to as the second inner face; and - a power supply lead disposed between the first and second electrodes, the so-called SPD system comprising a suspension in a suspension medium Micron-sized and/or sub-micron-sized particles that selectively (and preferably) take the shape of (micro) droplets And dispersed in a matrix of a polymer which is preferably crosslinked, the SPD system having a given thickness E of preferably less than or equal to 150, even equal to 130 microns or even 100 microns, and the spacers, especially Peripheral, transparent, and preferably plastic spacers are incorporated into the matrix or in a substrate-free medium, the method comprising the steps of: optionally in this order: - applying a liquid sealant to the first The inner surface of the first glass sheet of the electrode, surrounding the boundary of the inner surface, thus forming a liquid sealing portion; - incorporating the spacer into the liquid mixture having the particles and the medium or even incorporating the typical (pre) a polymer liquid matrix, which is formed before, during or after the formation of the liquid seal; - depositing a mixture having the spacers on the first glass sheet equipped with the first electrode by a wet process, Prepared before, during or after the application of the sealant, and in this order comprises the steps of: - after the sealant has been applied and the SPD system mixture having the spacers has been deposited, by two Lowering the glazing onto the first glass sheet, and bringing the first and second glass sheets into contact; - preferably pressing the first and second glass sheets with a roller; and - hardening the encapsulant (to seal The glass sheets), and optionally, the step of polymerizing or crosslinking the mixture before, during or after the hardening, in particular forming a matrix incorporating the microdroplets.

The use of seals and spacers will make it possible to control this thickness E and prevent loss of SPD material.

Applying the liquid mixture to the glass sheets before they are joined together The glass sheet is simpler than after the glass sheets are joined together.

The premixing of the spacers is simply made, and once the mixture is applied, a good distribution of the spacers is ensured.

The liquid sealant is preferably organic in nature, especially made of a UV curable resin.

Formation of the SPD system can include one or more steps of polymerization using any conventional mechanism (UV, etc.), particularly to form a polymer matrix of the droplet-containing SPD system.

Advantageously, the wet-processed deposition of the mixture is by a drop or line deposition process or the like.

The term line (or bead) is understood in its broadest sense as straight as possible, curved, parallel, crossed, and the like.

The drip or thread application is more precise than applying with a doctor blade and avoids wasting the material and/or contributes to the control of the micron thickness E.

For flat pressing, the rolling system is preferred, especially in order to have better continuous processing and improved throughput.

The roll pressure can be adjusted to spread the mixture and remove trapped air (bubbles). The first piece of glass operates translatingly, preferably horizontally.

Prior to the pressing step and preferably before the first and second sheets of glass have been brought into contact, by applying discontinuous beads of liquid sealant and/or by applying continuous beads of liquid sealant A break is created therein to form the splits, the method including forming a plurality of splits, each split defining a lateral seal end.

Before the rolling pressing step, and preferably at the first and second glass Preferably, at least two slits are positioned in the liquid seal adjacent to the first edge of the first glass sheet (glass sheet having curved or straight edges) and at least two before the sheet has been brought into contact The other slits face a first edge opposite the second edge, the edges corresponding to the edges in the rolling direction.

Prior to pressing the flattening step, and preferably before the first and second sheets of glass have been brought into contact, the liquid material of the sealing portion is in its width by the first facing the first sheet of glass At least two slits of the edge, at least two other slits facing the second edge opposite the first edge, at least two slits adjacent to the third edge of the first edge facing the first glass sheet, and Interrupted by at least the other two slits facing the fourth edge of the first glass sheet opposite the third edge.

Furthermore, the method may comprise applying the additional liquid sealant, preferably using a syringe, after the pressing step, and preferably before the hardening step, to form between the lateral ends of the seal. a bridge.

The additional sealant can be made of the same material as the sealant, thus ensuring the continuity of the material which is preferably organic in nature, especially the epoxy resin.

In particular, by cross-linking (preferably in the form of UV or even electron beam or by heating or even in air), preferably a single device or even a single operation is used to harden the encapsulant, and the additional encapsulant And even the hardenable component of the SPD mixture - especially the hardening of the liquid matrix - to form microdroplets comprising the SPD system in the crosslinked polymer matrix.

In particular, the method comprises, in one step, hardening the denseness, in particular by crosslinking. The encapsulant and the additional encapsulant, and/or especially the cross-linking harden the encapsulant and liquid matrix to facilitate formation of microdroplets comprising the SPD system in the crosslinked polymer matrix.

The SPD mixture can include a conventional crosslinking agent.

Preferably, the distance between the lateral ends of the seal may be at least 5 mm, such as 10 mm.

The outer surface of one of the glass sheets may include a reflective layer, such as a silver layer, such as to produce a rear view mirror, as is conventional.

1‧‧‧Stainless glass

2‧‧‧Stainless glass

3‧‧‧Electrode

4‧‧‧Electrode

5‧‧‧suspension device system

6‧‧‧Interval

7‧‧‧ Sealing Department

7’‧‧‧Sealant

11‧‧‧ inside

11’‧‧‧ inside

12‧‧‧ outside

21‧‧‧ inside

21’‧‧‧ inside

22‧‧‧ outside

24‧‧‧Stainless glass

31‧‧‧ electrode surface

41‧‧‧ electrode surface

71‧‧‧ Sealed end

71'‧‧‧ Sealed end

72‧‧‧ Sealed end

72'‧‧‧ Sealed end

73‧‧‧ Sealed end

73'‧‧‧ Sealed end

74‧‧‧ Sealed end

74'‧‧‧ Sealed end

81‧‧‧Rip

82‧‧‧Rip

83‧‧‧Rip

84‧‧‧Rip

100‧‧‧Projector

110‧‧‧ Reflected light

120‧‧‧reflected light

200‧‧‧ digital camera

300‧‧‧ screen

Other details and features of the present invention will become apparent from the following detailed description of the drawings, wherein: Figure 1 (above) shows a schematic cross-sectional view of a light valve not according to the present invention; 2 is a schematic cross-sectional view showing a light valve according to a first embodiment of the present invention; - FIG. 3 is a schematic view of an apparatus for measuring a refractive defect indication value; - FIG. 4 is based on a glass planarity distribution map Y(x) The principle behind the formation of a radiographic image on the screen; - Figure 5 shows an example of a local illumination profile E(x) and an average illumination profile E0(x); - Figure 6 shows a schematic top view of a light valve in accordance with the present invention In particular, the seal portion and the splits are shown; - Figure 6a shows a schematic top view of the light valve in the variant of Figure 6, in particular It shows the seal and the splits; - Figure 7 shows a schematic plan view of the light valve according to the invention during manufacture, in particular showing the seal and the splits.

These drawings are not in a certain proportion. For the sake of simplicity, only such particles, and not such microdroplets, are displayed.

The embodiment shown in Fig. 2 shows the design of a light valve in the first embodiment in accordance with the present invention.

For example, two conductive layers 3, 4 made of indium tin oxide (ITO) having a thickness of about 20 to 400 nm and having outer surfaces 31, 41 are deposited in the two floating glass sheets 1 and 2, respectively. Face 11, 21 on. The ITO layers have a sheet resistance between 5 Ω/□ and 300 Ω/□. Instead of a layer made of ITO, it is also possible to use other conductive oxide layers or silver layers for the same purpose, the sheet resistance of which is comparable.

The SPD system 5 of thickness E is located between the electrode layers 3 and 4 and may be a fluid (particles suspended in a suspension medium) or preferably a micro-droplet of a medium containing suspended particles. Union) polymer matrix.

The SPD system 5 contains a peripheral spacer. The spacers 6 are made of a hard transparent polymer. As an example, the product of Sekisui Chemical Co., Ltd., which is known by the trade name "Micropearl SP", has been exemplified as a suitable spacer.

In order to ensure the uniformity of the thickness E and thus ensure the optical performance of the light valve, each of the glass sheets 1, 2 having the electrodes 3, 4 is according to the present invention. The light is selected to have a refractive defect indication value that is measured by radiographic photography in reflection.

This basic principle is related to geometric optics. A schematic of the device is shown in Figure 3.

Luminous flux is projected onto a face 11 of the glass sheet (whether or not coated with an electrode) by a small source such as projector 100, which face 11 is intended to be the inner face. After being reflected by the inner face 11 of the glass sheet, a projected image is observed on the screen 300. This image is captured by the digital camera 200 for processing. The reflection from the second face 12 is offset by the use of a wet black cloth placed behind the glass sheet 1, and the glass is bonded to the wet black cloth via capillary action.

4 shows the principle behind the formation of a radiographic image on the screen 300 based on the glass planarity map Y(x). The recessed areas (concentration defects) in the glass sheet concentrate the incident reflected light 110 and thus produce localized over illumination of the screen 300. The raised areas (diverging defects) in the glass sheet spread the incident reflected light 120, and thus the localized illumination of the screen 300 is insufficient.

Figure 5 shows an example of a local illumination profile E(x) and an average illumination profile E0(x).

When the local illumination E(x) is equal to the average illumination E0(x), the contrast is zero, and thus Y"(x) = 0 and the optical power is zero.

When the local illumination E(x) is higher than the average illumination E0(x), the contrast is negative and Y"(x) < 0. This is an indication of a convergence defect corresponding to the center in the glass Depression.

When the local illumination E(x) is lower than the average illumination E0(x), the contrast is positive and Y"(x) > 0. This is an indication of a divergence defect corresponding to the convexity in the glass degree.

In order to illustrate the principle of operation of the apparatus, it is known that the planarity variation in the unprocessed width direction is large, and the planarity profile in a plane perpendicular to the flow direction and perpendicular to the surface of the glass will be considered. .

By the law of geometric optics and conservation of energy, it can be exemplified by the illumination measured on screen E(x) corresponding to one point x on the abscissa of the glass, and the distribution map Y(x) of the surface of the glass. There is a relationship between them.

After some geometric simplification based on the assumption that the device ensures a near normal reflection and the source is considered a source, the following relationship is obtained:

Here: Y (x): The glass profile; D: glass - screen distance; and E _0: x, on the average illumination (which will be a plane without defects).

Furthermore, the optical power in the reflected POR (in the refracting power) is given by:

Here the contrast C(x) system makes:

This contrast corresponds to the "lines" (here, because a profile, rather than an area being considered), which can be seen in a radiographic image projected onto the screen.

For each pixel of the image, a processing suite software calculates the comparison and thus calculates the optical power in the reflected POR.

The refractive defect indication value (in milli-deficiencies) reflects the uniformity of the optical power, and in fact is the standard deviation σ of the distribution of optical power in the reflection above the inner surface, as defined by the relationship:

here: : an average of the square of the optical power above the entire inner surface; and The square of the average of the optical power above the entire inner surface.

Depending on T _L , the indication value must be lower than E/3 or 2E/3 in order to ensure a sufficient optical quality in transmission, that is, a good uniformity of the light transmittance in the closed state.

As an example, for a standard 600 ton / day capacity float glass line with 3.5 m untreated glass sheet width: -2.1 mm thick glass sheet can be less than about 22 mdt; -3 mm The indication value of the thick glass piece may be less than about 11 mdt; the indication value of the -4 mm thick glass piece may be less than about 8 mdt; The indication value for a -6 mm thick glass sheet can be less than about 5 mdt.

At its edge, the SPD system is sealed by an adhesive seal 5, which at the same time has the effect of firmly and permanently joining the glass sheets 1, 2 equipped with electrodes.

The adhesive sealant that seals the separate glass sheets 1 and 2 at its edges, for example, contains an epoxy resin.

As shown in Figure 6, the seal has a given width L and is interrupted in its width by a plurality of splits 81-84, each split defining a lateral seal end 71 to 74'.

More precisely, the sealing portion 7 is in its width by the two slits 81 to 82 facing the first edge of the light valve and by the other two facing the second edge opposite the first edge The slits 83, 84 are interrupted, and these edges correspond to the edges in the assembly direction of the sheets of glass, the assembly of which is preferably achieved by rolling.

For each split, an additional sealant 7' forms a bridge between the adjacent lateral ends of the seal, the bridge being made, in particular, of the same material as the sealant, thus ensuring continuity of material Sex, as shown in Figure 6a.

The light valve 100 is preferably dark (nearly black) in the initial (this closed state), i.e., prior to application of voltage. Once the power source is turned on, the layer switches to a slightly transparent state, i.e., the state in which the line of sight is no longer blocked, under the effect of the alternating electric field provided.

The light valve is preferably produced using the method described in detail below.

Reactive magnetron sputtering method in a workshop with continuous coating capability It is used to coat a float glass sheet having a ITO layer of approximately 100 nanometers thick in a continuous sputtering chamber.

Two separate glass sheets of equal size are cut from the large glass sheets coated in this manner by the desired size and are ready for the rest of the processing.

The two separate glass sheets that are cut to the desired size are first subjected to a cleaning operation.

A mixture is formed and contains suspended particles in a medium, or even a liquid prepolymer matrix, and is further incorporated into the spacers.

This mixture is then applied to one of the two glass sheets, for example, preferably on the side of the electrode thus treated, preferably leaving an uncovered boundary around the glass sheet 1, the width of the border being, for example It is about 2 to 10 mm.

The deposition system is achieved, for example, using so-called drip or line deposition techniques. A drip dispensing device, or a dropper, is employed to deposit a finely adjustable dispensing quantity on a glass substrate.

The liquid sealant (adhesive, etc.) forming the seal portion 7 is applied directly along the edge of the glass sheet 24, either continuously or discontinuously, before or after deposition of the liquid mixture of the SPD system. . Its width can be, for example, 2 to 10 mm.

At this point, the liquid mixture containing the spacer is surrounded by the liquid sealant.

As shown in Figure 7, a plurality of slits 81 through 84 are provided in the still liquid seal having a size and configuration such that they are suitable for emptying any excess liquid mixture, such slits 81 through 84. It Each defines two adjacent end portions 71 to 74' of the lateral side seal portion 7.

To achieve this, the application of the liquid sealant is discontinuous, or continuous, and a breach is then established (by removing material 7) before or after deposition of the SPD mixture.

When the two separate glass sheets are then preferably pressed using a roller, the liquid layer 7 is compressed downward to a thickness E of the layer.

The slits 81 to 84 thus have the effect of: - evacuating the excess mixture, and thus allowing the thickness of the SPD system to be better controlled, and thus preventing loss of optical quality; and - degassing the mixture, In order to stop the subsequent formation of bubbles in the SPD system, and thus the loss of optical quality is again prevented.

Preferably, at least two slits are positioned on the leading edge past the edges of the rollers, and at least two slits are positioned on the edges of the rollers.

The width of the lateral ends is, for example, 10 mm. The higher the viscosity of the SPD mixture, the more cracks are used. Second, the rolling pressure is carried out.

If a flat press is selected, the split is pre-applied to the other edges.

Next, with a syringe, the additional liquid sealant 7' is applied such that a bridge is formed between the lateral ends of the seal portions 71 to 74', and the additional sealant is preferably made of the sealant Made of the same material to ensure continuity in the sealant material. For example, it may be a resin which is preferably crosslinked under UV.

Finally, the encapsulant and the additional encapsulant are hardened (UV crosslinked) and the polymer matrix of the microdroplet-containing SPD system is crosslinked (below UV).

1‧‧‧Stainless glass

2‧‧‧Stainless glass

3‧‧‧Electrode

4‧‧‧Electrode

5‧‧‧suspension device system

6‧‧‧Interval

7‧‧‧ Sealing Department

11‧‧‧ inside

12‧‧‧ outside

21‧‧‧ inside

22‧‧‧ outside

31‧‧‧ electrode surface

41‧‧‧ electrode surface

100‧‧‧Projector

Claims (17)

A light valve (100) comprising: - first and second float glass sheets (1, 2), by means of a sealing portion on the periphery of opposite main faces of the inner faces (11, 21) 7) sealed, the sealing portion is made of a given sealant; - on the main face (11) of the first glass piece, the first electrode (3) is made of a transparent conductive layer; On the main surface (12) of the second glass piece, the second electrode (4) is made of a transparent conductive layer; - the first and second electrodes are provided with power supply leads; and - on the inner faces (11) Between 21), the SPD system (5) includes particles suspended in a suspension medium, the SPD system is incorporated into the spacer (6) and has a given thickness E, the thickness A1 of the first glass piece. Is less than or equal to 6.5 mm; the thickness A2 of the second glass sheet is less than or equal to 6.5 mm, and when the light valve has a light transmittance T _{L of} less than 5% no power, the first and second inner faces Each having a refractive index indication value expressed in milli-degrees of luminosity, which is E/3 or less, where the thickness E of the SPD system is expressed in microns, E is 100 microns or less; or when the light valve 5% to 15% powerless The transmission ratio T _L, each of the first and the second inner surface having a refractive defect indicator value expressed in milli diopter, which based 2E / 3 or less, the thickness E of the SPD based systems this micrometers Expression, E is 50 microns or less. For example, the light valve (100) of claim 1 of the patent scope, wherein the first glass The thickness A1 of the glass sheet, and preferably the thickness A2 of the second glass sheet is 4.5 mm or less, even 3.5 mm or less, and preferably 1.6 ± 0.2 mm or more. The light valve (100) of any one of claims 1 and 2, wherein when the light transmittance T _L is less than 5%: - for a thickness A1 between 5.5 mm and 6.5 mm Preferably, it is used for a thickness A2 between 5.5 mm and 6.5 mm, which is 20 microns or less; - for thicknesses A1 between 4.5 mm and 5.4 mm, and preferably for 4.5 mm and The thickness A2 between 5.4 mm, the thickness E is 30 microns or less; - the thickness A1 between 3.5 mm and 4.4 mm, and preferably the thickness A2 between 3.5 mm and 4.4 mm, the thickness E is 35 microns or less; - for thickness A1 between 2.5 mm and 3.4 mm and preferably for thickness A2 between 2.5 mm and 3.4 mm, the thickness E is 50 microns or less; For thicknesses A1 between 1.9 mm and 2.4 mm, and preferably for thicknesses A2 between 1.8 mm and 2.4 mm, the thickness E is 90 microns or less; and - for 1.3 mm and 1.8 mm The thickness A1, and preferably the thickness A2 between 1.3 mm and 1.8 mm, is 100 microns or less. The light valve (100) according to any one of claims 1 to 2, wherein when the light transmittance T _L is from 5% to 15%: - for a thickness A1 between 5.5 mm and 6.5 mm And preferably for thickness A2 between 5.5 mm and 6.5 mm, the thickness E is 10 microns or less; - for thickness A1 between 4.5 mm and 5.4 mm, and preferably for use at 4.5 a thickness A2 between millimeters and 5.4 mm, the thickness E being 15 micrometers or less; - a thickness A1 between 3.5 mm and 4.4 mm, and preferably a thickness A2 between 3.5 mm and 4.4 mm, The thickness E is 35 microns or less; - for a thickness A1 between 2.5 mm and 3.4 mm, and preferably for a thickness A2 between 2.5 mm and 3.4 mm, the thickness E is 25 microns or less - for a thickness A1 between 1.9 mm and 2.4 mm and preferably for a thickness A2 between 1.9 mm and 2.4 mm, the thickness E is 45 microns or less; and - for use at 1.3 mm and The thickness A1 between 1.8 mm is preferably used for a thickness A2 between 1.3 mm and 1.8 mm, which is 50 microns or less. The light valve (100) of claim 1 or 2, wherein the spacer (6) content ranges from 0.1 to 1% by weight of the SPD system, and preferably less than 0.5% by weight of the SPD system . The light valve (100) of claim 1 or 2, wherein the SPD system comprises a crosslinked polymer matrix having droplets, the droplets containing The suspension medium and the particles. The light valve (100) of claim 1 or 2, wherein the sealing portion (7) has a given width L and is interrupted by a plurality of slits (81 to 84) in its width, each slit defining The lateral side seal ends (71 to 74'), and for each split, a material referred to as the additional sealant (7') forms a bridge between the lateral ends of the seal, which The bridge is made in particular from the same material as the sealant, thus ensuring the continuity of the material. The light valve (100) of claim 7, wherein the sealing portion (7) is interrupted in its width by at least two of the slits (81 to 82), the slits being located facing each other a first edge of the light valve, and interrupted by at least two of the slits (83 to 84), the other slits being located at a second edge facing the light valve, and the second edge The first edge is opposite. The light valve (100) of claim 1 or 2, wherein the sealing portion (7) and/or the additional sealant (7') are organic in nature. A method for manufacturing a light valve (100), such as defined in accordance with one of the aforementioned patent claims, and comprising: - first and second float glass sheets (1, 2), The periphery of the main faces, which are referred to as inner faces (11, 21), are sealed by a sealing portion (7) made of a given sealant; the first electrode (3), at On the inner surface (11) of the first glass piece; - a second electrode (4) on the inner surface (12) of the second glass piece; and - a power supply between the first and second electrodes Lead wire The SPD system (5) comprises particles suspended in a suspension medium, preferably in the form of (micro) droplets, dispersed in a matrix of a preferably crosslinked polymer, the SPD system being incorporated into the spacer. Part (6) and having a given thickness E, the method comprising the steps of: - applying a liquid sealant (7) to the inner face of the first glass sheet (1) equipped with the first electrode (3); a spacer incorporating a liquid mixture having the particles (5) and the medium; - depositing a mixture (5) having the spacers at a first portion equipped with the first electrode (3) by a wet treatment Float glass sheet (1), and the following steps are in this order: - after the material of the sealing portion has been applied and the SPD system mixture having the spacers has been deposited, by lowering the second glass sheet To the first glass sheet, the first and second glass sheets (1, 2) are brought into contact; - the first and second glass sheets are pressed; and the sealing agent is hardened. A method for manufacturing a light valve (100) according to claim 10, wherein the wet-processed deposition system or the line deposition method of the mixture (5) having the spacers. A method for manufacturing a light valve (100) according to any one of claims 10 and 11, wherein before the pressing step and preferably before the first and second glass sheets have been brought into contact, By applying discontinuous beads of liquid sealant and/or by applying continuous beads of liquid sealant In which an interruption is created to form the slits, the method includes forming a plurality of slits (81 to 84), each slit defining a lateral side seal (7) end (71 to 74'). A method for manufacturing a light valve (100) according to the scope of claim 12, wherein before the pressing step as the rolling step, and preferably before the first and second glass sheets have been brought into contact, The liquid material of the sealing portion (7) is interrupted in its width by at least two slits (81 to 82) facing the first edge of the first glass sheet, and by facing the second edge of the light valve At least the other two slits (83 to 84) are interrupted, and the second edge is opposite the first edge, and the first and second edges correspond to edges in the rolling direction. A method for manufacturing a light valve (100) according to the scope of claim 12, wherein the sealing portion is before the step of pressing the flat, and preferably before the first and second glass sheets have been brought into contact ( 7) the liquid material is at least two slits (81 to 82) in its width by facing the first edge of the first glass sheet, by at least the other facing the second edge opposite the first edge a second slit (83 to 84), at least two slits (81 to 82) adjoining the third edge of the first edge facing the first glass sheet, and by facing the first glass sheet At least the other two splits (83 to 84) of the fourth edge opposite the three edges are interrupted. A method for manufacturing a light valve (100) according to claim 10 or 11, wherein the method comprises applying an additional liquid sealant (7'), preferably using a syringe, after the pressing step, and preferably Forming a gap between the lateral ends of the sealing portions (71 to 74') before the hardening step Bridge. A method for manufacturing a light valve (100) according to the fifteenth aspect of the patent application, wherein the additional sealant (7') is made of the same material as the sealant (7), thus ensuring that it is preferably in essence The continuity of organic materials, especially epoxy resins. A method for manufacturing a light valve (100) according to claim 10 or 11, wherein the method comprises, in one step, hardening the sealant, in particular by cross-linking, with the additional sealant, and/or especially by The sealant and liquid matrix are hardened to form an SPD system comprising microdroplets in the crosslinked polymer matrix.