JPH07502840A - Light modulation device including improved electrodes - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Light modulation device including improved electrodes Related statements This specification refers to ``UV polymerizable matrices and polymers with various light transmittances''. Dispersed liquid crystal device and its manufacturing method J (Pol)+ner-DispersedL iquid Crystal Device) loving an Ultr aviolet-PolymerizableMatrix and a Va riable 0ptical Transmission and Meth Miller entitled od for Preparing the Same) United States Patent Application (Case Docket No. 44609USAIB, January 1992 I 0), which was filed concurrently with this specification and is directed to the same assignee as the present application. has been established. This is incorporated herein by reference.

Background of the invention field of invention The present invention relates to improved electrodes for light modulators.

Description of related technology A light modulator is a light modulator whose optical properties change in response to an electric field to reverse or reverse the electric field. or a device that returns to its original state when removed. One example of a light modulator is an electronic It is an electrochromic device. like this The device relies on reversible chemical reactions that produce changes in optical properties. Another example is the electric field sign This is a liquid crystal display device whose optical appearance changes over time.

A third example of a light modulating device is, for example, U.S. Pat. No. 4.435. of Fcrgason. The so-called nematic linear aligned phase (M( ! ma mouth c Curvilinear Aligned Phase (NCAP )) device. These devices have a liquid crystal material encapsulated in a polymer matrix. Contains a liquid crystal layer. The material is a liquid crystal material and a polymer matrix in an aqueous emulsion. and casting the film from the emulsion Manufactured by These devices produce light scattering when no electric field is present. It is relatively translucent when an electric field is applied, but it is relatively transparent when an electric field is applied.

A fourth example of a light modulating device is, for example, U.S. Pat. No. 4.688.90 to Doane et al. This is a polymer dispersed liquid crystal (PDLC) device described in No. 0. These devices are liquid crystal liquid The droplets include a liquid crystal layer dispersed throughout a polymer matrix. This LCD The layer includes a liquid crystal and a polymerizable matrix precursor (e.g., one or more UV polymerizable monomers) and subjecting this mixture to polymerization conditions. Manufactured by Polymerization results in phase separation of liquid crystal material 1, resulting in polymer maturation. Forming liquid crystal droplets dispersed throughout the linox. Like the NCAP device, PDLC devices are translucent in the absence of an electric field due to scattering and transparent in the presence of an electric field. It is.

All of the above light modulation devices apply an electric field on at least one side of the electroactive layer. requires a transparent electrode. The other electrode can be transparent or opaque . Suitable transparent electrodes generally fall into two categories.

The first category consists of non-metal transparent materials such as indium tin oxide (ITo) or tin oxide. Contains degenerate semiconductors that are bright conductors. Ferguson U.S. Pat. No. 4.435. The NCAP device described in No. 047 uses such electrodes. These electrodes are It has the advantage of exhibiting high transmittance and low reflectance of visible light. They are , for example, is relatively stable against chemical deterioration to the liquid crystal layer; Additional retention table 7-502840 (3) There would be no need to provide protection. However, their conductivity and solar controllability (i.e., the degree to which the electrode impedes the transmission of invisible light by reflection or absorption) It is not optimal for this purpose.

The second classification includes metallic conductors such as silver that are transparent when applied as thin films. nothing. Such electrodes have the advantage of high conductivity and good solar control. have The higher conductivity of these conductors has partially conductive electroactive materials Enables large-area display structures. But they are chemical, thermal and purple It is susceptible to external radiation degradation, thus limiting device life. Furthermore, their penetration and reflection properties are not optimal.

Overcoating the metal surface with a dielectric layer to protect it from chemical and physical attack It is known to provide metal films (eg, silver films) that are but, In such applications, metal films are not used to apply the electric field. do not have. For example, Haas et al., pplied 0ptics, 14(11) :2639~44(+975) is a sulfur while maintaining the reflectance of silver metal at the same time. Al2O to protect the sheet metal from clouding due to hydride and moisture attack, and A silver mirror coated with SiOx film is described.

Application of a dielectric film to a metal film changes the optical properties of the underlying metal film. It is also known as Seuroko. For example, Kusano et al., J, Vac, Sc i, and Tech, A4(6):2907-10 (1986) , for example, describes transparent heat reflective films of zinc oxide and silver. here, The silver layer reflects infrared light, and the oxide layer suppresses visible light reflection. 5ainty et al. Appl, Optics, 23(7):1116-19 (19984) The dielectric film on the film protects the metal from the environment and its optical properties. (e.g. by changing its reflective properties) It describes what can be done. In both cases, however, gold Genuine films do not use the application of an electric field.

Van Konyncnberg et al. 5PIE Volume 823, 0ptical M materialsTechnology for Energy Efficiency ency and 5olar [! energy Conversion Vl, PP, 143-50 (1987) Controls Solar Irradiation Including NCAPCA Phase Material Layers The window for doing so is listed. One side of the electrode is said to be "low emissivity" glass. Ru. However, its composition has not been further specified.

Ferguson, U.S. Pat. No. 4,810,063 describes a substrate supporting a layer of liquid crystal material. The back surface of the material (i.e., the surface furthest from the liquid crystal material layer) ” describes an NCAP device that includes a dielectric coating.

Examples of suitable coatings include lithium fluoride and barium oxide. coati The purpose of this is to provide selective constructive and This is to perform destructive optical interference. However, the coating Described as tin oxide, tin oxide, antimony doped tin oxide or conductive ink. (listed) may apply.

Summary of the invention In general, the present invention provides a method for connecting metal N-electrodes to a an electroactive layer to which an electric field is applied (i.e., the optical properties change in response to the applied electric field) layer), where at least one of the electrodes has a layer that is resistant to electrode degradation (e.g. Electrodes and electricity to improve resistance (to chemical, heat, moisture and ultraviolet light induced degradation) A light modulating device further includes a passivated thin film dielectric layer sandwiched between the active layer.

This dielectric passivation layer (i.e. has a light absorption of less than 10% and Layers made from materials with a conductivity lower than lO' mho/cm) are preferred. or applied to both electrodes of the light modulator. In this way, electrode life and and thereby extend the life of the equipment.

If both electrodes are provided with a dielectric layer, the dielectric layer of each electrode is the same as the dielectric layer of the other electrode. It may be the same as or different from the electrical layer. thicker virtually opaque gold The metal electrodes are also protected by the dielectric layer.

Corrosive chemical components in the electroactive layer are responsible for the deterioration of metal electrodes, but the rate of deterioration is influenced by environmental factors. , for example, affected by heat, moisture and UV radiation. The electroactive layer is electrolytic. chromic materials (e.g. tungsten oxide), liquid crystal materials, PDLC materials or In the case of NCAP material, the metal electrodes are protected by a thin dielectric passivation layer. Vine.

Appropriate refractive index and thickness of both electroactive layer and metal layer By selecting a dielectric layer (in comparison), the dielectric layer can Provides the added benefit of a tuning layer that increases transmittance and decreases reflectance sell. If the device is incorporated into a window for e.g. architectural or automotive applications , reflectance and thickness are transmission at a wavelength of 550 nm, the midpoint of the visible spectrum. Preferably, it is selected to increase the transmittance and decrease the reflectance.

Maximizing transmission and minimizing reflection reduces glare and improves window appearance .

If tunability is desired, the refractive index of the dielectric layer is similar to that of the electroactive layer. It should be between the refractive indices of the poles. The refractive index of metal electrodes is effectively very (usually higher than 2), and the refractive index of the electrode is the upper limit of the refractive index of the dielectric layer.

For anisotropic PDLC and NCAP layers, the refractive index of the layer for this purpose is The average refractive index of the mer matrix and the ordinary and extraordinary refractive index of the liquid crystal material Should be considered average. The larger the difference in refractive index between the dielectric layer and the electroactive layer (the refractive index of the metal electrode is the upper limit), the tuning effect is significant. in general, The difference should be at least 0.2. In many electroactive layers, at least This requirement is met by selecting a dielectric layer with a refractive index of 1.9.

The device can also be made to exhibit color (instead of being transparent) upon application of an electric field.

For example, select a dielectric layer that exhibits a unique color due to selective absorption in the visible light region. This can be achieved by:

Alternatively, the refractive index and thickness of the dielectric layer can be selected to achieve the color. Furthermore , the metal electrode itself consists of one or more metal and dielectric layers (dielectric in contact with the electroactive layer). in addition to layers). Examples of such composites are The electrode may be a dielectric layer sandwiched between two metal layers.

Silver is the preferred material for metal electrodes due to its optimal electrical and solar control properties. other Suitable metals include gold, copper, aluminum, titanium, chromium, iron, nickel and the like. Contains these alloys. Preferred materials for the dielectric layer are rays in the visible spectrum (i.e., wavelengths between 400 and 800 nm) It is not absorbed into the body. Suitable materials are metal oxides, sulfides, halides and including combinations thereof. A120h, Snow, indium-tin oxide (IT○), ZnO, Cent, Taz Os, Zr (L and Ti Metal oxides such as Or are particularly preferred.

The material selected for the dielectric layer, its thickness and method of deposition will depend on the application of the electrode. It is important that the material is selected so that its conductivity or optical properties are not degraded. . The conductivity of the electrode after application of the dielectric layer is at least O, OO1 mhos/sq, Preferably it is 0.1 mhos/SQ. The dielectric layer has this level of conductivity. Designed to protect the metal from deterioration to ensure that it is maintained.

The conductivity of the protected electrode, as fully explained in the detailed description of the preferred embodiments. at least 50%, preferably at least 75% of the Retained after 20 weeks of exposure to a water bath chamber containing several UV lamps is desirable.

The dielectric layer is used to maintain electrical contact and to prevent visible defects due to delamination (e.g. Good adhesion to the electroactive layer is also important to prevent the formation of gaps, e.g. be. Preferably, the force required to separate the dielectric layer from the electroactive layer (electrode by peeling from the electroactive layer) is at least 100 in the 1800 peel test. gm/2°54cm (]00gm/in).

The shading factor is a measure of the degree of solar control that the device exhibits. preferable As fully explained in the Detailed Description of the Embodiments, it includes a window fitted with a light modulating device. The amount of solar energy incident on the window and the amount of solar energy incident on the window without a device Calculated by comparison with quantity. In general, if the shading coefficient is a low value, Thickness rejected by the window (i.e. by absorption or more preferably reflection) in the presence of an electric field. The amount of sunlight is high. By applying a thin dielectric passivation layer to the electrode, the device can be attached. The shading coefficient of the window is preferably 0.5 or less when an electric field is applied.

Protects transparent metal electrodes from deterioration that has until now limited their practical use in light modulators. Transparent metal electrodes outperform non-metallic electrodes such as indium-tin oxide while protecting Light modulators that take advantage of advantages (e.g., superior solar control and electrical conductivity) provide. Furthermore, through careful selection of refractive index and thickness, the dielectric layer Protects the metal electrode and maximizes transmittance and reduces reflections in the presence of electric fields 2. Tuning the incident light to reduce glare (thereby reducing glare) Able to perform functions. These features make such protected metal electrodes Light modulating devices containing the present invention become particularly useful in windows for architectural and automotive applications.

Other features and advantages of the invention include the following detailed description of the preferred embodiments and a brief description of the drawings. Akira Referring to FIG. 1, which is a partial cross-sectional view of a PDLC device including an electrode of the present invention, the present invention includes: will be more fully understood.

Detailed description of preferred embodiments The present invention is useful for thin film, protective, passivation applications in a variety of light modulating devices. A transparent or opaque metal electrode with a dielectric layer (i.e., transparent to light in the visible spectrum) transparent). Known light modulators include an electroactive layer (i.e., when an electric field is applied) layer whose optical properties change) is electrochromic, liquid crystal, PDLC or NC Contains devices that are AP materials. In all these devices, metal electrodes are electrically active. chemical attack by components of the sexual layer, as well as environmental factors such as heat, moisture and ultraviolet radiation. vulnerable to attacks. For example, based on tungsten oxide, e.g. Ctrochromic devices typically require the transfer of hydrogen ions to produce optical changes. Partially dependent on movement.

However, when these ions come into contact with metal electrodes, corrosion can occur. liquid crystal In the case of , PDLC and NCAP layers, the liquid crystal itself can be corrosive. PDLC and NCAP layers suffer from further drawbacks in that the polymer can attack the electrodes. will be treated.

The present invention is particularly useful in PDLC devices. Preferred PDLC devices and their Examples of manufacturing methods are described in the above-referenced Miller et al. patent application. child These devices are made of gold, copper, aluminum, titanium, chromium, iron and nickel (mostly Metallic silver electrodes are typically used, although metal silver electrodes (and alloys thereof) may also be used. Silver includes windows. It is a particularly desirable electrode material for applications such as This is because it has good conductivity (e.g. For example, approximately 7xlO” mhos/cm) and shading coefficient (more below) It will be explained in detail. ), it shows sunlight controllability.

However, despite these advantages, the applications of silver metal electrodes are limited. That's called The silver tends to be attacked by both the liquid crystal and the polymer matrix. It is from. If the PDLC matrix is e.g. In the case of a UV curable thiol-ene matrix, as described in the This is especially true. In the case of a thiol-ene matrix, unreacted mercap The butane moieties can attack and chemically degrade silver metal electrodes. Thin film passivation on electrode Providing a dielectric layer protects against such attacks.

The light modulating device described in the above Miller et al. application exhibits positive dielectric anisotropy; Therefore, the liquid crystal material in the PDLC film aligns when current is passed through the device, and the device Becomes transparent. The electrode of the invention is equally applicable to light modulators exhibiting negative dielectric anisotropy. With no electric field, the liquid crystals are aligned and the device is transparent, and with an electric field applied, the device is transparent. Becomes opaque. The discussion here generally focuses on immobile parts inside devices that exhibit positive dielectric anisotropy. The described parameters for the device describe the dielectric layer and exhibit negative dielectric anisotropy. Suitable modifications will be apparent to those skilled in the art.

An example of a thin film PDLC device 10 including an electrode of the present invention is shown in FIG. In this aspect , the device IO has a multiplicity of liquid crystal droplets 14 dispersed in a polymer matrix 16. A PDLC film 12 is included. The first and second soft base materials 18 and 20 are supporting thin film metal electrodes 22 and 24, which in turn support a thin film passivated dielectric. Coated by layers 26 and 28. Base materials 18 and 20 are PDLC films A cell comprising a PDLC film 12 with passivation layers 26 and 28 in contact with 12. form a switch. In this way, the PDLC film 12 is a PDLC film. Immobility that provides a barrier to protect the electrodes from potentially corrosive materials at 12 Because they are in direct contact with the oxidized layer, electrodes 22 and 24 are protected from degradation.

Soft base materials I8 and 19 include polyethylene terephthalate 1-(PET) and copolymer. polyester, polyether sulfone, polyimide, poly(ethylene naphthalene) various materials including is used. PET is the preferred material.

Electrodes 22 and 24 of the PDLC device IO are connected to the seeds through leads 30 and 32. It is connected to an alternating current (AC) supply power source 34 having different voltage outputs. Alternating current The period of the electric field should preferably be in the range 40-100 hertz. Electric field applied The electric field changes rapidly enough so that a person observing the device under normal conditions does not notice any flicker. Should.

Regardless of the type of light modulator, the dielectric layer must be compatible to be useful. There are some basic requirements that do not exist. First, the thickness and density of the layers are such that the layers are electroactive layers. The vine acts as a barrier to the diffusion of chemical species from the electrode to the electrode, and the environment The thickness must be such that it acts as a barrier. However, it is It must be thin enough not to substantially reduce the electric field applied to the electroactive layer. do not have.

Specific values for density and thickness depend on the particular dielectric and electroactive materials used. There will be. Generally it should be 1/4 wavelength of the optical thickness. 1 The /4 wavelength dimension is such that the electrode thickness maximizes transmission of incident light and minimizes reflection. Determined by depositing a dielectric material on top. l/4 wavelength of a given dielectric material The thickness will vary depending on the metal used for the electrode. cross the electroactive layer For electric field reduction, the thickness of each dielectric layer is preferably 10% of the thickness of the electroactive layer. It is as follows. In a typical PDLC device, this is approximately 5-2000 nm thick. It is interpreted that

The second requirement is that the dielectric material and its method of deposition must be compatible with the underlying electrode. That means no. “Compatibility J refers to the material itself and its attachment to the electrode. Both of the methods used to It means that it will be possible. For example, oxide deposition processes often heating a metal electrode, especially when an oxide is sputter coated onto the electrode; or oxidize, thereby reducing conductivity.

The third requirement is that the dielectric layer is This means that it must be optically inert to substantially affect the performance of the device. Ru.

The fourth requirement is that the dielectric layer must adhere well to both the underlying electrode and electroactive layer. This means that it must be done. If adhesion is not sufficient, the electrode and electroactivity Electrical contact between the layers will be lost.

Delamination also occurs due to the reduced electric field across the electroactive layer corresponding to the region of delamination. It will result in visual defects when etching. Visual defects in the device may also Due to the presence of air with a low refractive index between the metal electrodes and the electroactive layer, the electric field It would be obvious in the absence of .

Peel strength is a measure of the force required to separate the electroactive layer between the electrodes and the two sets of electrodes. be. For devices with at least one layer of soft substrate, the peel strength is 15. 2c Instrumentor at a speed of m/m i n (6i n/m i n) Measured by 1800 peel test using s5lip/Peel Te5ter. It will be done. For example, PDLC devices with proper droplet generation and curing generally require Figure 3 shows adhesive layer failure between the electrical layer and the electroactive layer. Preferably, the peel force is PDL At least 100 gm/2.54 cm (100 g/in). The second most common failure mode is This is the breakdown of the adhesive layer between the attached metals, and the adhesion between the dielectric layer and the metal electrode is the best. It's also big.

barrier properties, optical properties without substantially reducing the electric field applied to the electroactive layer. The ability of a single dielectric material to exhibit properties, adhesive properties, and material compatibility is a surprising discovery. It was. Notably, the dielectric layer is connected between the electrode and the power supply through the dielectric layer. did not impair the ability to make electrical connections. The dielectric layer is actually an adhesive electrical connector can protect the electrode from chemical attack from What is even more surprising is that the number It has been determined that different dielectric materials can provide the desired balance of properties. The fact is that

In addition to providing protection against degradation, dielectric layers improve the optical properties of the device. It can also be selected to For example, the optical thickness of a dielectric layer is determined by its refractive index and its physical thickness. The optical thickness of the dielectric layer determines the transmission and reflection characteristics of the device. affect sexuality. A dielectric with a refractive index sufficiently larger than that of the electroactive layer. By selecting the body layers, the dielectric layer maximizes the transmission of visible light when an electric field is applied. , which acts as an optical "tuning" layer to minimize reflections. like this The properties are particularly useful for applications involving windows. This is because they do not reduce glare. This is because optical transparency is improved by this. In such applications, 550n It is desirable to maximize transmission and minimize reflection at m.

It is also possible to achieve a certain degree of tuning effect with a small difference in refractive index. be. However, if tuning is desired, maximizing the refractive index difference is preferable. In the case of the PDLC material described by Miller et al., the refractive index is small. Charging can be achieved by selecting a dielectric layer that is at least 1.9 (preferably 2° or more). A significant difference is achieved.

The thickness of the dielectric layer for tuning applications depends on the dielectric material as well as the composition of the electroactive layer. It will depend. Generally, the thickness of the dielectric layer depends on the layer's protective ability and tuning. between 25 and 1100n to take advantage of both the

In the visible light range, the optical transmittance and reflectance of the resulting device vary with wavelength If so, the dielectric layer can also be used to impart color to the device. by absorption Using an inherently colored dielectric layer, using a single layer with a sufficiently high refractive index , or by using multiple dielectric or metal layers, this can be achieved. sell. If multiple metal layers are used, metal-dielectric-metal (MDM) structures In this case, the thickness of the dielectric material between the metals can be tuned by using the l/2 wavelength thickness. can be achieved. The innermost metal electrode is an electroactive layer with an additional dielectric protection layer. will be protected from.

The use of transparent metal electrodes improves the solar control properties of the light modulator. What is solar controllability? , while blocking radiation in parts of the spectrum other than visible light (e.g. infrared). Refers to the ability to transmit visible light into a device. absorb unwanted radiation, or Blocking is achieved by reflection, and reflection is preferred.

The degree of solar control exhibited by a device is expressed by its shading coefficient. be able to. The shading coefficient (Sc) is incident on a window equipped with a light modulation device. and the amount of solar energy incident on a transparent 1/8 inch thick window glass. This is the comparative ratio. The lower the shading coefficient, the more solar energy is blocked. The amount of lugie is large. The shading coefficient is calculated by the following equation.

where Sc is the shading coefficient; Tsf is the shading coefficient of the window equipped with the light modulator. is the sunlight transmittance: Tsg is the sunlight transmittance of the window glass; Asf is the light modulation Asg is the solar absorption coefficient of the window equipped with the device; Asg is the solar absorption coefficient of the window glass. R: R is a weighting factor that varies depending on the window application.

Air Mass 2 To calculate the shading coefficient of the sunlight spectrum Using.

Essentially R is the amount of solar energy absorbed by the window, followed by convection and Less energy inside than absorbed, removed from the window by conduction to the outside It is a measure of the amount relative to the amount conducted to.

This balance of external and internal energy gains and losses is It is a function of the angle of airflow. Common in vertical configurations with no airflow For a typical window glass, R is 0.25, Tsg is 92% and Asg is 0% (ASHRAE Handbook of Fundamentals , Chapter 27. p, 27.24. 0° referred to (+989) ).

The use of a passivated dielectric layer allows for low solar energy transmission for practical use of metal electrodes. It allows for high solar reflectivity and low 0-shading coefficient. Like Alternatively, a shading coefficient lower than 0.5 is obtained. To achieve translucency light scattering in the absence of an electric field and in the presence of an electric field to increase transparency. In the case of PDLC and NCAP devices based on alignment of liquid crystals, shading It is clear from the above discussion that the number is slightly higher in the presence of an electric field than in the absence of an electric field. As such, the selection of a particular material for the passivating dielectric layer depends on the function the layer will perform, e.g. , protection against degradation only, or a combination of protection and tuning), and will depend on the particular material forming the electroactive layer. In general, suitable materials is a metal oxide (e.g. Hf0z, YiOs, Zr0t, Pr*Oz .

Sez Oi, 5ioSSbz Oi, Bit Oi, 5iOz, Ta205 , T4CL, Tha2, especially A I20s, 5no2, ITO1ZnO 1CeO2, Taz Os 1. Zr0t and T102), sulfides (e.g. Zn5), halides (e.g. AgCL MgF+), solution or gas phase Based on coated organic polymers, or combinations thereof. PDLC device In the case of , A l 20 + is preferred when a protective only layer is desired; SnO2 is preferred for both protection and tuning (Snow and The difference in refractive index of most PDLC materials is A1. Compared to the difference shown when using O, , greater than. ).

A passivating dielectric layer is generally applied over the metal electrode using standard thin film deposition techniques. . These techniques include vacuum deposition, sputter coating, cathodic arc deposition, Includes spray pyrolysis and chemical vapor deposition (CVD). Specific deposition methods and rows conditions (e.g., temperature, reactive gas pressure, etc.) may vary depending on the specific materials used in the equipment (i.e., dielectric materials, metal electrodes and electroactive materials).

The invention will be more fully understood with reference to the following examples.

It should not be construed as limiting the scope of the invention.

General manufacturing method of electrodes The manufacture and characteristics of the electrode of the invention are described below.

25 μPET base coat in vacuum web coater by both evaporation and sputtering methods. A silver electrode was vacuum deposited on top. Regarding the vacuum evaporation of silver, nitriding is included in the borosilicate crucible. 12.2 m/m i (40 f t/m i n) on a free span web moving at a speed of n). sputtered silver For 4. using argon as sputtering gas at 5μ pressure.　6m/m Gold is deposited on the free span web moving at a speed of i (15ft/m1n). The target was magnetron sputtered. The output level applied to the metal source is 5 Provides transmittance of 60%, 55%, 50% and 45% measured at 50nm wavelength. The silver layer was chosen to deposit a silver layer with a thickness of

The approximate thickness of these silver films is calculated from the optical properties of the coated electrodes. , respectively, 12.0 om and 13. Znm, 14°6om and 16,8om There was.

Passivation of SnO2 on 50% transmittance silver film and 45% transmittance film The dielectric layer is heated by reactive magnetron spacing on the web, which is cooled by a cooling roll. Sputter coating was performed by means of a sputtering method.

The sputtering gas composition contains 70 standard cubic centimeters (SCCm) of oxygen or A homogeneous mixture was produced by a mixed flow of argon and loO of 8 ccm. Al The passivated dielectric layer of 2O, is a resistive aluminum crucible containing AI gold metal. were reactively deposited onto a 60% transmittance silver film and a 50% transmittance film. 7 Oxygen, maintained at a flow rate of 470 sec at a pressure of xlO' Torr, reacts. Used as a reactive gas in reactive vapor deposition methods. Film thickness is determined by aging resistance and was chosen to provide both the functionality of maximum transmission at 550 nm and maximum transmission at 550 nm. S Regarding the n02 film, the thickness is about 35 nm, which is the same as that of the Al2O+ film. In this case, it was approximately 45 nm. Indium-tin oxide electrode (ALTAIR- 0-30,7 mil PET) from Soujhwall Technologies, Purchased from Pa1o Alto, CA.

The metal-dielectric-metal (MDM) electrode was approximately 13n on a PET support (25μ thick). Sputter coating a first layer of Ag with a thickness of 530 m Reactively evaporate an Al2O8 dielectric layer with a thickness of 90 nm, corresponding to a half-wavelength separation in nm. and sputtering a second Ag layer of approximately 17 nm on the Al2O3 layer. Manufactured by coating. The second or outermost Ag layer is A It was protected from the PDLC film by a dielectric protective layer of 1□03.

Optical measurements (i.e., % visible light transmittance, % visible light reflectance, % solar transmittance, and % Perkin Elmer Lambda 9 with an integrating sphere Measured using a spectrophotometer. All measurements were performed without an applied electric field. of integrating sphere A sample was placed directly on the port to measure total transmission and reflection. . The results of the optical measurements are shown in Table 1, where "T" means transmittance and "R" means reflectance. Taste.

Table 1 Optical properties of the electrode before PDLC coating The results in Table 1 are as shown in Examples 1 to 5. The inclusion of a thin layer of dielectric passivating material compared to an uncoated silver film Therefore, the visible light transmittance value approaches that of the indium-tin oxide (ITO) sample (C-1). The reflectance is said to be lower than that of uncoated materials (C-2 and C-3). This shows that improved optical properties were obtained.

The conductivity of the electrode manufactured in Example 1 was also determined using an LRI non-contact conductive probe. The results are shown in Table 2.

Table 2 Electrical properties of the electrode before PDLC coating Conductivity results of the passivated dielectric material The conductivity of the coated electrodes in (Examples 1 and 2) is the same as that of the uncoated silver electrodes (Examples 1 and 2). This shows that there is no substantial change from Examples C-1 and 2). All metal electrodes are indica It had a substantially higher conductivity than the umium-tin oxide (Example C-1).

General manufacturing method of PDLC Using the electrode manufactured in Example 1, a light modulating device in which the electroactive layer is a PDLC film is used. Manufactured using They are Miller et al.'s U.S. Patent Application No. No. 44609 USAIB, filed on January 10, 1992) Manufactured using. Generally, the manufacturing method is as follows. Equal parts by weight of LICR ISTAL E7 (EM Industries, Hawthorne, N Y) and N0A65 (Norland Products, Inc., Ne w Thiol-ene based polymers available from Brunswick, NJ. trix material) to approximately 60°C while mixing until the liquid crystal material is completely dissolved. did. This liquid crystal/uncured polymer matrix material blend is applied to transparent electrodes in advance. Each film (with or without a protective passivating material coating) A pair of 25 micron thick polyester films coated on one side of the I poured it in between. The two films are placed on the nip roll of a precision two-roll nip coater. The electrode-coated surfaces were held in face-to-face relationship. between the nip rolls The spacing is such that the film thickness of the liquid crystal material/uncured polymer matrix material is 10 to 21. It was set to be microns.

Other commercially available liquid crystal materials useful in the fabrication of PDLC devices utilizing electrodes of the present invention include LI CRISTAL BLOO6, BLOO9, BLO36, BLO38, MLIO 05, MLI08.17151, 17153 and 17315 (all EM I industries, ) Iawthorne.

(available from NY).

Other thiol-ene-based materials useful in the fabrication of PDLC devices utilizing the electrodes of the present invention. The polymer matrix material used is N0A68 (Norland Product available from New Brunswick, NJ). .

A sample containing two electrode-coated substrates and a liquid crystal material/uncured matrix material. The switch-like structure is used as a fluorescent light source (fluorescent black). a pair of phosphor lighting elements) The polymer matrix is polymerized by placing it between opposite banks; Here, each bank is placed so that one side of the polyester film is illuminated. 3 Spectral distribution from 00 nm to 400 nm and maximum output at 351 nm A light source was used.

The light source was 1.1 mW/c through each electrode coated polyester film. was adjusted to provide an average intensity of m2. Each side of the sandwich-like structure] 00 mJ/Cm" total energy irradiation. The structure as a whole received 200 mJ/Cm" mJ/cm” total energy.The average intensity on sample 8 was 0.5 mW/cm”. Cm2, and the total irradiation was 330 mJ/cm2. 300-400nm range The incident radiation dose was determined by the BIT low-intensity UVIMAP radiometer with a spectral response of was determined and had a maximum transmission at 358 nm.

Electrically conductive adhesive tape (i.e. 3M9703 placed on 3M copper foil tape) z-axis conductive tape) is not pre-coated with liquid crystal/matrix material. Each electrode was fixed to a portion of the coated base (A) along the edge. Then, Each tape is connected to an alternating current (AC) power supply with various voltage outputs to power the device. It is now possible to switch between a state with an electric field and a state without an electric field.

The optical properties of the device were determined using the same procedure described for measuring the optical properties of the electrodes. However, optical measurements were performed using a device without an electric field. Place for reflectance measurement separate measurements were taken on the top and bottom of the device (depending on the electrodes used in the device). Since they had different compositions, their reflection properties are expected to be different. ).

The results are shown in Table 4. The 7 aging coefficients for each device were calculated and the results are shown in Table 4. child.

Table 3 Electrode configuration of PDLC device Optical characteristics of PDLC device The results shown in Table 4 show that PDLC devices fabricated using thin film passivated dielectric layers The scales exhibit the optical properties listed above (i.e., 7 and 8). Non-condensable water bath UV sun lamp, GE type R3M-6, 24 Hr in chamber, 50% impact coefficient It was measured by exposing it to. The stability of the electrode is determined by the conductivity of the PDLC matrix, and not by the conductivity of the PDLC matrix. The conductivity of the electrode is monitored by the LEI non-contact conductivity probe that measures the area conductivity of the electrode. It was measured by monitoring. Ag, a corrosive component in P D L C film Any reaction with reduced the conductivity of the electrode. protected electrode and protected The electrodes without the following liquid crystal/polymer matrix mixture as shown: In the first 20 weeks of E7/N0A65, BLOO9/N0A65, the protected electrodes It showed better retention of conductivity than unprotected electrodes. Metal electrode and PD The aluminum oxide or tin oxide layer between the LC layers resists corrosion under the test conditions. Protect poles. After a small initial decrease in conductivity, many passivated samples remain in an environmental chamber. Increasing exposure to - shows little or no change.

Environmental Stability Study - Conductivity measurements at the beginning of the test and after 20 weeks are reported in Table 6. I will inform you. This data shows that when weathered, under study conditions, PDLs containing LCD E7 C devices suffered the greatest reduction in conductivity, while PDLC devices containing liquid crystal BLOO9 We show that devices that suffer intermediate conductivity losses and do not contain liquid crystal material are the most stable. .

The 180° peel strength measurement of the above PDLC device was performed according to the test procedure described above. The results are shown in Table 7.

Table 7 Peel strength of PDLC devices with and without dielectric protection Specifications and figures above Reasonable changes and improvements within the scope of this invention may be made within the scope of the invention as defined in the appended claims. This is possible without departing from the scope of the present invention.

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Claims (16)

[Claims] 1. An electric field is applied through a pair of metal electrodes, at least one of which is transparent. a light modulating device comprising an electroactive layer comprising at least one of said pair of electrodes; In order to improve the deterioration resistance of the electrode, one of the electrodes is connected to the electrically active electrode. a thin passivating dielectric layer sandwiched between A light modulation device further including a dielectric layer. 2. 2. The device of claim 1, wherein said electroactive layer comprises a layer of PDLC material. 3. 2. The device of claim 1, wherein said electroactive layer comprises a layer of material that includes liquid crystals. 4. The device of claim 1, wherein said electroactive layer is an electrochromic material. . 5. Both of the aforementioned electrodes feature a thin passivated dielectric layer to improve resistance to degradation. The apparatus according to claim 1. 6. The refractive index and thickness of said dielectric layer are such that the refractive index and thickness of said dielectric layer 2. The device of claim 1, wherein the device is selected to increase transmission by and decrease reflection. 7. The difference between the refractive index of the dielectric layer and the electroactive layer is at least 0. 7. The device according to claim 6, wherein: 8. The materials for the metal electrodes include silver, gold, copper, aluminum, titanium, chromium, The device according to claim 1, which is selected from the group consisting of nickel, iron, and alloys thereof. Place. 9. The device of claim 1, wherein the dielectric layer does not substantially absorb light in the visible region. . 10. The dielectric layer may contain metal oxides, sulfides, halides, and their like. 2. The device of claim 1, wherein the device is selected from the group consisting of: 11. said electrode with said dielectric layer has a conductivity of at least 0.001 mh; os/sq. The apparatus according to claim 1. 12. Apparatus according to claim 1, wherein the shading coefficient of the apparatus is lower than 0.5. . 13.24 Hr, in a water bath chamber containing an ultraviolet sun lamp with an impact coefficient of 50%. After 20 weeks of exposure, the conductivity of said electrode with said dielectric layer is at least 2. The device of claim 1, wherein 50% is retained. 14. Light containing an electroactive PDLC layer where an electric field is applied through a pair of transparent silver electrodes A modulation device, wherein the electrode is configured to improve resistance to deterioration of the electrode. For this purpose, a thin passivated dielectric layer sandwiched between said electrode and said PDLC layer is further In preparation for this, the dielectric layer is made of Al2O3, SnO2, indium monotin oxide, Z selected from the group consisting of nO, CeO2, Ta2O5, ZrO2 and TiO2 Light modulator. 15. An electric field is applied through a pair of metal electrodes, at least one of which is transparent. 2. A light modulating device comprising an electroactive layer, wherein one or more of said pair of electrodes In order to improve the deterioration resistance of the electrode, one of the electrodes and the electric further comprising a thin film passivated dielectric layer sandwiched between the active layers, the light modulating device A light modulating device further comprising a current supply power source. 16. Light modulation with thin film metal electrodes with improved resistance to corrosive contaminants A method of manufacturing a device, the method comprising depositing a passivated dielectric material on the electrode. applying a thin film; a pair of electrodes in which at least one electrode includes a thin film of passivating material; forming a layered structure with an electrochemically active material contained between the electrodes; wherein said passivating material is bonded to said electrochemically active material and said metal electrode. sandwiched between the electrochemically active materials and at least one polymerizable monomer. containing electrochemically active materials in mixtures with );and, said electrochemically active material so as to form a matrix encapsulating said electrochemically active material. A method comprising the steps of: polymerizing a polymerizable monomer.