CN113138515A

CN113138515A - Method for changing state of electrochromic film

Info

Publication number: CN113138515A
Application number: CN202110067823.6A
Authority: CN
Inventors: 王坚; 周焱
Original assignee: Furcifer Inc
Current assignee: Furcifer Inc
Priority date: 2020-01-20
Filing date: 2021-01-19
Publication date: 2021-07-20

Abstract

The present disclosure generally relates to a method of changing the optical state of an electrochromic film. The electrochromic film may have a plurality of optical states. The method may include selecting a desired state of a plurality of optical states; injecting charge into the electrochromic film; monitoring the amount of charge injected into the electrochromic film; and stopping injecting the electric charges when the electric charges reach a preset amount corresponding to the desired state.

Description

Method for changing state of electrochromic film

Cross Reference to Related Applications

This application is a partial continuation of U.S. patent application No.15/913,669 filed on 6.3.2018, the entire contents of which are incorporated herein by reference.

Technical Field

The present disclosure relates generally to electrochromic films, and in particular, to methods for changing the state of electrochromic films.

Background

Electrochromism is a phenomenon exhibited by some materials that reversibly change optical properties by inducing electrochemical redox (reduction and oxidation) reactions in the electrochromic material using charge bursts. The optical properties may include transmittance, reflectance, absorptance, emissivity, and color. In particular, electrochromic materials exhibit a reversible color change. The optical state of the electrochromic material depends on the amount of charge injected or extracted. The optical state of the electrochromic film may relate to brightness, transparency, color, reflectivity, and the like. By controlling the amount of charge, the optical state of the electrochromic film can be set to any state. In smart window applications, electrochromic films are integrated with glass windows to become available. The electrical controller is used to control an electrochromic film integrated with a glass window (i.e., a smart window). In addition, the color of the electrochromic film may change according to a change in transmittance of the electrochromic film, or may deteriorate or change over time due to electrochemical cycling.

In this disclosure, we propose different methods for changing the optical state of an electrochromic material, such as an electrochromic film. We further propose different devices and methods for adjusting the color of smart windows comprising electrochromic materials, for example, to compensate for changes in transmittance of the electrochromic film or electrochromic cycling. We further propose different apparatus and methods to power the controller of a smart window while determining the transmittance of the electrochromic film.

Disclosure of Invention

One aspect of the present disclosure relates to a method of changing the optical state of an electrochromic film. The electrochromic film may have a plurality of optical states. The method may include selecting a desired state of a plurality of optical states; injecting charge into the electrochromic film; monitoring the amount of charge injected into the electrochromic film; and stopping injecting the electric charges when the electric charges reach a preset amount corresponding to the desired state.

Another aspect of the present disclosure relates to another method of changing the optical state of an electrochromic film. The electrochromic film may have a plurality of optical states. The method may include selecting a desired state of a plurality of optical states; extracting charge from the electrochromic film; monitoring the amount of charge extracted from the electrochromic film; and stopping extracting the electric charge when the electric charge reaches a preset amount corresponding to the desired state.

Another aspect of the present disclosure relates to another method of changing the optical state of an electrochromic film. The method may include setting a plurality of predetermined optical states of the electrochromic film; determining an amount of charge corresponding to each of a plurality of predetermined optical states; selecting a desired state of a plurality of predetermined optical states; and adjusting the amount of charge within the electrochromic film to the determined amount of charge corresponding to the selected desired state.

Various embodiments of the present disclosure provide a method of changing an optical state of an electrochromic film in an electrochromic device, including: determining the color of the electrochromic film; determining an amount of adjustment to apply to the color; and controlling an amount of electric charge injected into and removed from the electrochromic film according to the determined adjustment amount.

In some embodiments, determining the adjustment amount to apply to the color further comprises determining a difference between the color and a target color of the electrochromic film. In some embodiments, the target color is the color of the electrochromic film in another electrochromic device in the same room, house, building, or residence. In some embodiments, the target color is preset to the same color for all electrochromic films in other electrochromic devices in the same room, house, building, or residence. In some embodiments, the target color is a color of the electrochromic film when the electrochromic film is in a dark state and an undegraded state. In some embodiments, the target color is a color of the electrochromic film when the electrochromic film is in a bright state and an undegraded state. In some embodiments, determining the adjustment amount to apply to the color further comprises: determining whether the difference is greater than a threshold amount; and in response to determining that the difference is greater than the threshold amount, injecting or removing charge in the electrochromic film until the difference is less than the threshold amount. In some embodiments, controlling the amount of charge injected into and removed from the electrochromic film comprises injecting or removing an amount of charge determined to achieve the target color of the electrochromic film. In some embodiments, determining the color of the electrochromic film comprises: determining a transmission state of the electrochromic film; and determining a color of the electrochromic film based on the determined transmission state and based on a relationship between the transmission state of the electrochromic film and the color of the electrochromic film. In some embodiments, determining the adjustment amount to apply to the color further comprises: determining an amount of adjustment to apply to the color based on a rate of change of the color relative to the change in transmission state. In some embodiments, controlling the amount of charge injected into and removed from the electrochromic film comprises applying an external DC voltage to the electrochromic film. In some embodiments, controlling the amount of charge injected into and removed from the electrochromic film comprises applying an external DC current to the electrochromic film. In some embodiments, controlling the amount of charge injected into and removed from the electrochromic film includes applying an external pulse voltage to the electrochromic film. In some embodiments, controlling the amount of charge injected into and removed from the electrochromic film comprises applying an external pulse current to the electrochromic film. In some embodiments, controlling the amount of charge injected into and removed from the electrochromic film includes applying a combination of an external voltage and an external current to the electrochromic film.

In some embodiments, determining the color of the electrochromic film includes determining the color reflected by the electrochromic film or determining the color transmitted by the electrochromic film. In some embodiments, determining the color of the electrochromic film includes determining one or more of a transmission color and a reflection color. In some embodiments, determining the color of the electrochromic film includes determining a refracted color.

In some embodiments, the method further comprises pre-installing the electrochromic device directly into the window frame.

Various embodiments of the present disclosure provide a method of changing an optical state of an electrochromic film in an electrochromic device, including: detecting the light intensity of external light; and adjusting a level of transmission of the electrochromic film based on the detected light intensity or the detected change in light intensity.

In some embodiments, the method further comprises detecting the light intensity while power is supplied to the electrochromic device. In some embodiments, detecting light intensity comprises: determining an amount of current generated during the supplying of the power; and detecting the light intensity based on the determined amount of generated current. In some embodiments, detecting the light intensity based on the determined amount of current generated includes detecting the light intensity based on a linear relationship between the light intensity and the amount of current generated.

Other objects, features and advantages of the described embodiments will become apparent to those skilled in the art from the following detailed description. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration and not limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.

Drawings

Preferred and non-limiting embodiments of the present invention may be more readily understood by reference to the accompanying drawings, in which:

fig. 1 is a diagram illustrating a simplified schematic diagram of an electrochromic device consistent with an exemplary embodiment of the present disclosure.

Fig. 2 is a simplified schematic diagram illustrating an electrochromic device including a solid polymer electrolyte therein, consistent with an exemplary embodiment of the present disclosure.

Fig. 3 is a diagram illustrating a controller consistent with an exemplary embodiment of the present disclosure.

Fig. 4 is a graph illustrating a response of an exemplary electrochromic film at a constant voltage from a dark state to a transparent state consistent with an exemplary embodiment of the present disclosure.

Fig. 5 is a graph illustrating the dependence of the transmission of an exemplary electrochromic film at a constant voltage on the amount of charge injected, consistent with an exemplary embodiment of the present disclosure.

Fig. 6 is a graph illustrating a response of an exemplary electrochromic film at a constant voltage changing from a transparent state to a dark state, consistent with an exemplary embodiment of the present disclosure.

Fig. 7 is a graph illustrating the dependence of the transmission of an exemplary electrochromic film at a constant voltage on the amount of charge extracted, consistent with an exemplary embodiment of the present disclosure.

Fig. 8 is a graph illustrating a response of an exemplary electrochromic film at a constant current changing from a dark state to a transparent state, consistent with an exemplary embodiment of the present disclosure.

Fig. 9 is a graph illustrating the dependence of the transmission of an exemplary electrochromic film at a constant current on the amount of injected charge, consistent with an exemplary embodiment of the present disclosure.

Fig. 10 is a graph illustrating a response of an exemplary electrochromic film at a constant current changing from a transparent state to a dark state, consistent with an exemplary embodiment of the present disclosure.

Fig. 11 is a graph illustrating the dependence of the transmission of an exemplary electrochromic film at a constant current on the amount of charge extracted, consistent with an exemplary embodiment of the present disclosure.

Fig. 12A, 12B, 13A, and 13B are schematic diagrams illustrating electrochromic devices (e.g., smart windows) consistent with exemplary embodiments of the present disclosure.

Fig. 14 is a graph illustrating an exemplary relationship between a change in color of an exemplary electrochromic device under a constant current and a change in transmittance from a transparent state to a dark state.

FIG. 15 is a schematic diagram of an exemplary tri-color source colorimeter.

Fig. 16 is a schematic diagram illustrating an electrochromic device (e.g., a smart window) consistent with an exemplary embodiment of the present disclosure.

Figures 17-18 are diagrams illustrating a stand-alone and self-powered controller powered by an energy generator such as a solar cell.

Detailed Description

Specific, non-limiting embodiments of the present invention will now be described with reference to the accompanying drawings. It should be understood that particular features and aspects of any embodiment disclosed herein may be used and/or combined with particular features and aspects of any other embodiment disclosed herein. It should also be understood that these embodiments are merely examples and are merely illustrative of a few embodiments within the scope of the present invention. Various changes and modifications apparent to those skilled in the art to which the invention pertains are deemed to be within the spirit, scope and concept of the invention as further defined in the appended claims.

Throughout the specification and claims, unless the context requires otherwise, the word "comprise" and variations such as "comprises" and "comprising" are to be interpreted in an open-ended, i.e., "comprising, but not limited to. Numerical ranges also include the numbers that define the range. In addition, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may be some examples. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

Electrochromic materials are commonly used in electrochromic devices. Fig. 1 is a diagram illustrating a simplified schematic diagram of an electrochromic device 100 (e.g., a smart window) consistent with exemplary embodiments of the present disclosure. The electrochromic device 100 may include two glass layers 101, two adhesive layers 102, an electrochromic film 103, one or more wires 104, and a controller 105 (shown in fig. 3).

The electrochromic film 103 may be sandwiched between two glass layers 101. The adhesive layer 102 is configured to attach the electrochromic film 103 to the glass layer 101. The integration of the electrochromic film 103 with the window (glass layer 101) is described in detail in patent application US 15/399,852, which is incorporated herein by reference. In some examples, the electrochromic film 103 may be attached to an outer layer of the glass 101 and/or secured to the glass 101, e.g., via a frame. In some examples, the electrochromic device 100 may be pre-mounted directly in the bezel.

One end 104a of the wire 104 is electrically connected to the electrochromic film 103. The other end 104b of the wire 104 is electrically connected to the controller 105. The controller 105 may be configured to control the state of the electrochromic device 100 by controlling the state of the electrochromic film 103. The controller 105 may be disposed outside the glass 101 or laminated between the two glass layers 101 similar to the electrochromic film 103.

In some embodiments, the adhesive layer 102 may comprise a polymeric material, particularly a thermoset polymeric material. Suitable thermoset polymeric materials may include, but are not limited to, polyvinyl butyral (PVB), Ethylene Vinyl Acetate (EVA), polyurethane, and the like. In some embodiments, the two adhesive layers may comprise materials that are not only configured to bond the electrochromic film thereto, but are also transparent. The two adhesive layers may comprise the same material or different materials.

According to one embodiment, the electrochromic film 103 includes a solid electrolyte disposed therein. The detailed structure of the electrochromic film 103 is shown in fig. 2 and described in detail below.

The exemplary electrochromic device 100 shown in fig. 1 can be a photochromic device as described in the specification and shown in other figures.

As shown in fig. 2, the electrochromic film 103 may include a first transparent conductive film 1312 and a second transparent conductive film 1310. The first conductive film 1312 and the second conductive film 1310 may have the same or different sizes, include the same or different materials, and the like. In some embodiments, the first and second transparent conductive films may be adhesive films as shown in fig. 1. In some other embodiments, the first transparent conductive film and the second transparent conductive film may be additional films. The first conductive film 1312 and the second conductive film 1310 may have a single-layer or multi-layer structure. Suitable materials for the first conductive film 1312 and the second conductive film 1310 may include, but are not limited to, tin-doped indium oxide (ITO), fluorine-doped indium oxide, antimony-doped indium oxide, zinc-doped indium oxide, aluminum-doped zinc oxide, silver nanowires, metal mesh, combinations thereof, and/or other such transparent materials that exhibit sufficient electrical conductivity. In a preferred aspect, the first conductive film 1312 and the second conductive film 1310 may include ITO.

As further shown in fig. 2, a layer 1314 of electrochromic material is deposited on an inner surface 1316 of first conductive film 1312. The electrochromic material layer 1314 is configured to achieve a reversible color change upon reduction (gain of electrons) or oxidation (loss of electrons) caused by an electrical current. In some embodiments, the layer of electrochromic material 1314 may be configured to change from a transparent state to a colored state, or from one colored state to another colored state, upon oxidation or reduction. In some embodiments, the layer of electrochromic material 1314 may be a polyelectrochromic material (polyelectrochromic material) in which there may be more than two redox states, and thus may take on a variety of colors.

In some embodiments, the electrochromic material layer 1314 may include an organic electrochromic material, an inorganic electrochromic material, a mixture of the two, and the like. The layer 1314 of electrochromic material can also be a reducing colored material (i.e., a material that becomes colored upon gaining electrons) or an oxidizing colored material (i.e., a material that becomes colored upon losing electrons).

In some embodiments, the electrochromic material layer 1314 may include metal oxides such as MoO3, V2O5, Nb2O5, WO3, TiO2, ir (oh) x, SrTiO3, ZrO2, La2O3, CaTiO3, sodium titanate, potassium niobate, combinations thereof, and the like. In some embodiments, the electrochromic material layer 1314 may include a conductive polymer, such as

poly

3,4 ethylenedioxythiophene (PEDOT), poly 2, 2' bithiophene, polypyrrole, Polyaniline (PANI), polythiophene, polyisothiophene, poly-o-aminophenol, polypyridine, polyindole, polycarbazole, polyquinone, octacyanophthalocyanine, combinations thereof, and the like. Further, in some embodiments, the layer of electrochromic material 1314 may include materials such as viologens, anthraquinones, phenothiazines, combinations thereof, and the like. Additional examples of Electrochromic materials, particularly those comprising multicolor Electrochromic polymers, can be found in U.S. patent application No. 62/331,760 entitled "multicored Electrochromic Polymer Compositions and Methods of Making and Using the Same" filed on 4.5.2016 and U.S. patent application No. 15/399,839 entitled "multicored Electrochromic Polymer Compositions and Methods of Making and Using the Same" filed on 6.1.2017. The entire contents of both of the above-referenced applications are incorporated herein by reference.

As further shown in fig. 2, a charge storage layer 1318 is deposited on the inner surface 1320 of the second conductive film 1310. Suitable materials for the charge storage layer 1318 may include, but are not limited to, vanadium oxide, binary oxides (e.g., CoO, IrO2, MnO, NiO, and PrOx), ternary oxides (e.g., CexVyOz), and the like.

In some embodiments, the charge storage layer 1318 may be replaced with an optional second layer of electrochromic material. The optional second layer of electrochromic material may have the same or different dimensions as the first layer of electrochromic material 1314, include the same or different composition as the first layer of electrochromic material 1314, and the like.

The electrochromic film 103 also includes an electrolyte layer 1322 disposed between the electrochromic material layer 1314 and the charge storage layer 1318. In some embodiments, electrolyte layer 1322 may comprise a liquid electrolyte as known in the art. In some embodiments, electrolyte layer 1322 may include a solid state electrolyte including, but not limited to, Ta2O5, MgF, Li3N, LiPO4, LiBO2 — Li2SO4, and the like. In some embodiments, electrolyte layer 1322 may include a polymer-based electrolyte including an electrolyte salt (e.g., LiTFSI, LiPF6, LiBF4, LiClO4, LiCF3SO3, LiN (CF3SO2)2, LiSbFg, LiAsF6, LiN (CF3CF2SO2)2, (C2H5)4NBF4, (C2H5)3CH3NBF4, LiI, etc.), a polymer matrix (e.g., polyethylene oxide, polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA), polyethylene oxide (PEO), Polyacrylonitrile (PAN), polyvinyl nitrile, etc.), and one or more optional plasticizers (e.g., glutaronitrile, succinonitrile, adiponitrile, fumaric acid nitrile, etc.).

In some embodiments, electrolyte layer 1322 comprises a solid polymer electrolyte. In one embodiment, a solid polymer electrolyte includes a polymer backbone, at least one solid plasticizer, and at least one electrolyte salt. In some embodiments, the polymer backbone can include a polar polymeric material having an average molecular weight of about 10,000 daltons or more. In particular embodiments, the polar polymeric material may have an average molecular weight of about 10,000 daltons to about 800,000,000 daltons. In some embodiments, the polar polymeric material may be present in an amount of about 15 wt% to about 80 wt%, based on the total weight of the solid polymer electrolyte.

The polar polymeric material may include one or more polar polymers, each of which may include one or more of the following: C. n, F, O, H, P, F, etc. Suitable polar polymers may include, but are not limited to, polyethylene oxide, polyvinylidene fluoride-hexafluoropropylene, polymethyl methacrylate, polyvinyl nitrile, combinations thereof, and the like. In embodiments where a variety of polar polymers are present, the polymers may be crosslinked to form a network with enhanced mechanical properties.

The polar polymeric material may be sufficiently amorphous to achieve sufficient ionic conductivity. Amorphous polymeric materials generally exhibit high ionic conductivity. Thus, in some embodiments, the polar materials disclosed herein can have an amorphous or substantially amorphous microstructure.

In some embodiments, the polar polymeric material may have a semi-crystalline or crystalline microstructure. In this case, various modifications may be made to the polymer material to suppress its crystallinity. For example, one modification may include the use of branched polar polymers, linear random copolymers, block copolymers, comb polymers, and/or star polar polymers. Another modification may include the addition of an effective amount of a solid plasticizer to the polar polymeric material, as discussed in more detail below.

Various properties of the polar polymeric material may also be selected and/or modified to maximize ionic conductivity. These properties may include, but are not limited to, glass transition temperature, segmental mobility/flexibility of the polymer backbone (polymer backbone) and/or any side chains attached thereto, orientation of the polymer, and the like.

As described above, the solid electrolyte of the present disclosure may include at least one solid plasticizer. The at least one solid plasticizer may be substantially miscible in the polymer backbone of the solid plasticizer. In some embodiments, the at least one solid plasticizer may include organic materials (e.g., small solid organic molecules) and/or oligomeric polymeric materials. In various embodiments, the at least one solid plasticizer may be selected from the group consisting of glutaronitrile, succinonitrile, adiponitrile, fumaric nitrile, and combinations thereof.

In some embodiments, multiple solid plasticizers may be present in the polymer backbone, where each plasticizer may independently comprise an organic material (e.g., small solid organic molecules) and/or an oligomeric polymeric material. In particular, each plasticizer may independently be glutaronitrile, succinonitrile, adiponitrile, fumaric acid nitrile, or the like. Further, at least two, some, most, or all of the plasticizers may be the same or different in size from each other.

In some embodiments, the total amount of solid plasticizer may be from about 20 wt% to about 80 wt%, based on the total weight of the solid electrolyte.

As described further above, the solid polymer electrolyte may include at least one electrolyte salt. In some embodiments, the at least one electrolyte salt may include an organic salt. In some embodiments, the at least one electrolyte salt may include an inorganic salt. Suitable electrolyte salts may include, but are not limited to: LiTFSI, LiPF6, LiBF4, LiClO4, LiCF3SO3, LiN (CF3SO2)2, LiSbFg, LiAsF6, LiN (CF3CF2SO2)2, (C2H5)4NBF4, (C2H5)3CH3NBF4, LiI, and combinations thereof. In some embodiments, the total amount of electrolyte salt may be about 10 wt% to about 50 wt%, based on the total weight of the solid electrolyte.

The solid polymer electrolyte is different from a conventional liquid electrolyte and a gel polymer electrolyte in which an ionic liquid is included. In other words, the solid polymer electrolyte disclosed herein may be an all-solid polymer electrolyte and does not include any liquid or gel components therein. The disclosed solid polymer electrolytes may also be transparent in certain aspects. In addition, the solid polymer electrolyte may have an ionic conductivity of about 10-7S/cm to about 10-3S/cm.

The method of making the solid polymer electrolytes disclosed herein can include synthetic, polymerization, solvation, and like processes known in the art. In one particular non-limiting embodiment, a method of making a polymer electrolyte of the present disclosure can comprise: (a) combining a polymer backbone, at least one plasticizer, and at least one electrolyte salt in a suitable solvent; (b) the solvent was removed to obtain a solid polymer electrolyte. Exemplary solvents may include, but are not limited to, acetone, methanol, tetrahydrofuran, and the like. In some embodiments, one or more experimental parameters may be optimized to facilitate dissolution of the polymer backbone, plasticizer, and electrolyte salt in the solvent. These experimental parameters may include components remaining in the solvent, agitation/stirring of the solvent, and the like.

In some embodiments, electrolyte layer 1322 of fig. 2 includes a solid polymer electrolyte, such as the solid polymer electrolytes described above, and does not include any liquid or gel electrolyte. Such a solid polymer electrolyte (i) has sufficient mechanical strength but is versatile in shape so as to be easily formed into films and film-like products; (ii) avoiding problems associated with adhesion and printing processes that affect conventional electrolytes; (iii) providing a stable contact between the electrolyte/electrode interface (the interface with and without the electrochromic material coating thereon); (iv) avoiding the leakage problems typically associated with liquid electrolytes; (v) has the ideal characteristics of no toxicity and no flammability; (vi) avoiding problems associated with evaporation due to insufficient vapor pressure; (vii) exhibits improved ionic conductivity compared to conventional polymer electrolytes; and the like.

Additional examples of Electrolyte materials, particularly those including Solid Polymer electrolytes, can be found in U.S. patent application No. 62/323,407 entitled "Solid Polymer Electrolyte for electrochemical Devices" filed on 15/4/2016 and U.S. patent application No. 15/487,325 entitled "Solid Polymer Electrolyte for electrochemical Devices" filed on 13/4/2017. The entire contents of both of the above-referenced applications are incorporated herein by reference.

The electrochromic film 103 may be used for various applications and/or replacements (permutations), which may or may not be mentioned in the illustrative embodiments/aspects described herein. For example, in some embodiments, the electrochromic film 103 may include more or fewer features/components than those shown in fig. 2. Additionally, unless otherwise indicated, one or more components of the electrochromic film 103 may be of conventional materials, design, and/or fabricated using known techniques (e.g., sputtering, Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), Plasma Enhanced Chemical Vapor Deposition (PECVD), spray coating, slot-die coating, dip coating, spin coating, printing, etc.), as will be appreciated by one of skill in the art upon reading this disclosure.

Fig. 3 is a diagram illustrating a controller 105 consistent with an exemplary embodiment of the present disclosure. The controller 105 may include a power converter 301, a power output controller 302, and a signal receiver 303. The power converter 301 may convert input power from a power source into power required by the signal receiver 303 and the power output controller 302. The power source may be a power source integrated with the controller 105 as a stand-alone self-powered unit, or an external power source provided by, for example, the power source of the building in which the electrochromic device is installed. The power output controller 302 may be configured to supply power to the electrochromic film 103. In particular, the power output 302 may be configured to provide a voltage between the first conductive film 1312 and the second conductive film 1310. Since the state of the electrochromic film 103 is driven by electric charges, the power output controller 302 can inject or extract an amount of electric charges into or from the electrochromic film 103 based on a signal received by the signal receiver 303 in order to change the state of the electrochromic film 103. The signal receiver 303 may be configured to receive signals sent to the controller 105 and to transmit the signals to the power output controller 302. In some embodiments, the signal receiver 303 may be connected to external switches and a central switch to provide local and global control of the electrochromic device 100.

In this application we propose different methods for changing the optical state of the electrochromic material. The optical state of the electrochromic material can be changed by injecting or extracting charges into or from the electrochromic film. Both voltage drive and current drive can be used to inject/extract charge. In addition, a combination of voltage driving and current driving can also be employed. Further, the voltage drive and the current drive can be operated under Direct Current (DC) or Alternating Current (AC). The electrochromic film can be set in a certain optical state as long as a desired amount of electric charge is injected or extracted.

Changing optical state of electrochromic film by voltage drive

In one embodiment, changing the optical state of the electrochromic film can be operated by a DC voltage. An external power supply outputs a constant voltage to the electrochromic film. The current through the film and the light transmission through the film can be monitored over time. By applying a constant voltage, charges are injected into the electrochromic film, causing oxidation of the film, thereby changing its optical state.

Example 1

The exemplary electrochromic film operates at a constant voltage of 1.5V. Fig. 4 presents the response of an electrochromic film changing from a dark state (with minimum transmission) to a transparent state (with maximum transmission) at a constant voltage. As shown in fig. 4, the current density of the electrochromic film continuously decreases with time, while the transmittance of the electrochromic film increases with the applied voltage and becomes saturated after 20 seconds. This may indicate that the electrochromic film only needs a certain amount of charge to change its state.

Fig. 5 shows the dependence of the transmittance of the electrochromic film on the amount of charge injected at a constant voltage of 1.5V. As the amount of injected charge increases, the transmittance of the electrochromic film increases. By controlling the amount of charge injected into the electrochromic film, the transmittance of the electrochromic film can be adjusted accordingly. Therefore, the transmittance of the electrochromic film can be set in any state by injecting a certain amount of electric charges. For example, if the transmittance of the electrochromic film is to be set to 40% of the dark state, it is necessary to set about 3mC/cm²Is injected into the electrochromic film.

In another embodiment, to change the state of the electrochromic film from a transparent state to a dark state, the polarity of the external voltage can be switched. By switching the polarity of the external voltage, it is possible to extract charges from the electrochromic film, causing the reduction of the electrochromic film, thereby changing its state.

Example 2

As shown in fig. 6-7, another exemplary electrochromic film operates at a constant voltage of 1V. Fig. 6 presents the response of an exemplary electrochromic film changing from a transparent state (with maximum transmission) to a dark state (with minimum transmission) at a constant voltage. As shown in fig. 6, a negative current density indicates that charge is extracted from the electrochromic film. As the current density decreases to zero, the transmittance of the electrochromic film decreases from a maximum value to a minimum value.

Fig. 7 shows the dependence of the transmittance of the electrochromic film on the amount of charge extracted at a constant voltage. As the amount of the extracted electric charge increases, the transmittance of the electrochromic film decreases. By controlling the amount of charge extracted from the electrochromic film, the transmittance of the electrochromic film can be adjusted accordingly. The transmittance of the electrochromic film can be set in any state by extracting a certain amount of electric charges. For example, if the transmittance of the electrochromic film is to be set to 35% of the transparent state, about 4mC/cm should be set in the electrochromic film²The charge density of (2).

Changing the optical state of an electrochromic film by current drive

In another embodiment, changing the optical state of the electrochromic film can be operated by a constant DC current. An external power supply outputs a constant current to the electrochromic film. The current through the film and the transmittance of the film can be monitored over time. By applying a constant current, charges are injected into the electrochromic film, causing oxidation of the film, thereby changing its optical state.

Example 3

Another exemplary electrochromic film is at 0.06mA/cm, as shown in FIGS. 8-9²At a constant current. Fig. 8 presents the response of an exemplary electrochromic film changing from a dark state (with minimum transmission) to a transparent state (with maximum transmission) at a constant current. As shown in fig. 8, the transmittance of the electrochromic film varies with a constant current supplied, and becomes saturated after about 70 seconds. When the transmittance of the film reaches a maximum, the constant current drops sharply. Since the amount of charge injected is equal to the current multiplied by the time, this may indicate that no additional charge injection is required after the state of the electrochromic film is completely switched from the transparent state to the dark state. Due to the fact thatHere, by controlling the amount of charge injected, the transmittance of the electrochromic film can be adjusted accordingly.

Fig. 9 shows the dependence of the transmittance of the electrochromic film on the amount of injected charge at a constant current. As the amount of injected charge increases, the transmittance of the electrochromic film increases. By controlling the amount of charge injected into the electrochromic film, the transmittance of the electrochromic film can be adjusted accordingly. The transmittance of the electrochromic film can be set in any state by injecting a certain amount of electric charges. For example, if the transmittance of the electrochromic film is to be set to 50% of the dark state, it is necessary to set about 3mC/cm²Is injected into the electrochromic film.

In another embodiment, to change the state of the electrochromic film from a transparent state to a dark state, the polarity of the external current can be switched. By switching the polarity of the external current, charge can be extracted from the electrochromic film, causing reduction of the electrochromic film, thereby changing its state.

Example 4

As shown in FIGS. 10-11, another exemplary electrochromic film is at 0.06mA/cm²At a constant current. Fig. 10 presents the response of an exemplary electrochromic film changing from a transparent state (with maximum transmission) to a dark state (with minimum transmission) at a constant current. As shown in fig. 10, a negative current density indicates that charge is extracted from the electrochromic film. The transmittance of the electrochromic film varies with a constant current supplied. When the transmittance of the electrochromic film reaches a minimum value, the constant current sharply decreases. Since the amount of charge extracted is equal to the current multiplied by the time, this may indicate that no additional charge extraction is required after the state of the electrochromic film is completely switched from the transparent state to the dark state. Thus, by controlling the amount of charge extracted, the transmittance of the electrochromic film can be adjusted accordingly.

Fig. 11 shows the dependence of the transmittance of the electrochromic film on the amount of charge extracted at a constant current. As the amount of the extracted electric charge increases, the transmittance of the electrochromic film decreases. By controlling the amount of charge extracted from the electrochromic film, the transmittance of the electrochromic film can be adjusted accordinglyAnd (4) adjusting. The transmittance of the electrochromic film can be set in any state by extracting a certain amount of electric charges. For example, if the transmittance of the electrochromic film is to be set to 40% of the transparent state, about 3mC/cm should be set in the electrochromic film²The charge density of (2).

Fig. 12A, 12B, 13A, and 13B show schematic diagrams of electrochromic devices 1200 and 1300 (e.g., smart windows), respectively, consistent with exemplary embodiments of the present disclosure. In fig. 12A, 12B, 13A, and 13B, the color of

electrochromic devices

1200 and 1300 may be monitored and/or changed. In some embodiments, the color of the

electrochromic devices

1200 and 1300 may refer to the color of the electrochromic films (e.g., 1203, 1303) in the

electrochromic devices

1200 and 1300.

Fig. 12A is a diagram illustrating an electrochromic device 1200 (e.g., a smart window) consistent with example embodiments of the present disclosure. Electrochromic device 1200 may include two glass layers 1201, two adhesive layers 1202, an electrochromic film 1203, one or more electrical wires 1204, a controller 1205, and a color sensor 1206 integrated into electrochromic device 1200. In some embodiments, the color sensor 1206 may be implemented as a spectrometer and/or a tri-source colorimeter, such as the tri-source colorimeter described with respect to fig. 15.

In some embodiments, the controller 1205 may include a signal receiver configured to receive current color information for the color coordinates or color dimensions of the electrochromic device 1200 from the color sensor 1206 and compare the received color information to a target color. The controller 1205 may adjust the current color of the electrochromic device 1200 to the target color according to the difference between the current color information and the target color. In some examples, the controller 1205 can adjust the current color of the electrochromic device 1200 to be closer to the target color. For example, the controller 1205 may adjust the current color of the electrochromic device 1200 to be within a predetermined threshold from the target color. In some examples, the controller 1205 may adjust the current color of the electrochromic device 1200 if the current color differs from the target color by more than a predetermined threshold, and the controller may not adjust the current color of the electrochromic device 1200 if the current color differs from the target color by less than or equal to the predetermined threshold. In some examples, the controller 1205 may receive information of the target color through global control. In some examples, the target color may be a baseline color of electrochromic device 1200 in a dark state, a transparent state, or any transmissive state. Additionally or alternatively, in some examples, the target color may be a color of electrochromic device 1200 that has not undergone electrochromic degradation or cycling (e.g., is in an undegraded state). In some examples, the target color may be predetermined based on the color of one or more other windows in the same room, house, building, or residence. For example, the target color may be the same color as the color of one or more other windows in the same room, house, building, or residence. In some examples, the target color may be preset to be the same color as all windows in the same room, house, building, or residence.

In some examples, the controller 1205 can determine color information based on the transmission state of the electrochromic device 1200. For example, the controller 1205 can use a spectrometer and/or a tri-source colorimeter to determine information about the optical state, e.g., the transmissive state, of the electrochromic device 1200, e.g., whether the electrochromic device 1200 is in the transparent state, the dark state, or somewhere in between the transparent state and the dark state. The controller 1205 may determine the color coordinates of the electrochromic device 1200 based on the transmissive state and a predetermined relationship between the color coordinates and the transmissive state of the electrochromic device 1200, such as the relationship 1400 shown in fig. 14. In some examples, the controller 1205 can also determine the rate of change of color coordinates relative to the change in transmittance state and/or transmittance phase of the electrochromic device 1200. The controller 1205 may determine the amount of adjustment needed based on the determined rate of change and the amount of charge to be injected or extracted. As described with reference to fig. 14, for example, the controller 1205 may determine that the electrochromic device 1200 may be in a first phase (e.g., 1406 in fig. 14), a second phase (e.g., 1408 in fig. 14), a third phase (e.g., 1410 in fig. 14), or a fourth phase (e.g., 1412 in fig. 14). In some examples, the controller 1205 may determine that the electrochromic device is in the first stage 1406 and that the controller 1205 needs to add more red and yellow to obtain the target color. From the determined color coordinates, the controller 1205 can determine the difference between the determined color coordinates and the target color coordinates and adjust the color of the electrochromic device 1200 to compensate for the difference between the determined color coordinates and the target color coordinates.

In some embodiments, the controller 1205 may be configured to adjust the color of the electrochromic device 1200 by injecting or extracting an amount of charge into the electrochromic device 1200. The controller 1205 may continuously monitor the current color of the electrochromic device 1200, continuously collect information of the difference between the current color and the target color, and continuously adjust the current color until the current color matches or differs from the target color by less than a threshold value. The controller 1205 may be configured to adjust the color of the electrochromic device 1200 to compensate for or account for changes in the transmission state and/or electrochromic degradation of the electrochromic device 1200.

Electrochromic film 1203 may be sandwiched between two glass layers 1201. Adhesive layer 1202 is configured to attach electrochromic film 1203 to glass layer 1201. The integration of the electrochromic film 1203 with the window (glass layer 1201) is described in detail in patent application US 15/399,852, which is incorporated herein by reference.

One end of the wire 1204 may be electrically connected to the electrochromic film 1203. The other end of the wire 1204 may be electrically connected to a controller 1205. The controller 1205 may be configured to control the optical state of the electrochromic device 1200 by controlling the optical state of the electrochromic film 1203. The controller 1205 may be disposed on the outside of the glass 1201 or laminated between two glass layers 1201 similar to the electrochromic film 1203.

In some embodiments, the adhesive layer 1202 can include a polymeric material, particularly a thermoset polymeric material. Suitable thermoset polymeric materials may include, but are not limited to, polyvinyl butyral (PVB), Ethylene Vinyl Acetate (EVA), polyurethane, and the like. In some embodiments, the two adhesive layers may comprise materials that are not only configured to bond the electrochromic film thereto, but are also transparent. The two adhesive layers may comprise the same material or different materials.

According to one embodiment, electrochromic film 1203 may include a solid electrolyte disposed therein. The electrochromic film 1203 may be implemented as the electrochromic film 103 as shown in fig. 1 and 2.

In some embodiments, as shown in fig. 12B, a color sensor 1206 may be disposed on an outer surface of the electrochromic device 1200. The color sensor may include an active sensing portion 1207. The active sensing portion 1207 may face the electrochromic device 1200, rather than the sun, in order to determine color information (e.g., color coordinates) of the electrochromic device 1200. Sunlight may reflect from electrochromic device 1200 and be received by color sensor 1206. The active sensing portion 1207 can determine the color reflected from the electrochromic device 1200. The color of the electrochromic film 1203 may include a reflective color.

Fig. 13A is a diagram illustrating an electrochromic device 1300 (e.g., a smart window) consistent with example embodiments of the present disclosure. The electrochromic device 1300 may include two glass layers 1301, two adhesive layers 1302, an electrochromic film 1303, one or more wires 1304, a controller 1305, and a color sensor 1306 integrated into the electrochromic device 1300. In some embodiments, the color sensor 1306 may be implemented as a spectrometer and/or a tri-source colorimeter, such as the tri-source colorimeter 1300 described above. The controller 1305 may be implemented as the controller 1205 of fig. 12A. The two glass layers 1301 can be implemented as the two glass layers 1201 of fig. 12A. The two adhesive layers 1302 may be implemented as the two adhesive layers 1202 of fig. 12A. The electrochromic film 1303 may be implemented as the electrochromic film 1203 of fig. 12A. The one or more wires 1304 may be implemented as one or more wires 1204 of fig. 12A.

In some embodiments, as shown in fig. 13B, the color sensor 1306 may be disposed on an inner surface of the electrochromic device 1300. The color sensor 1306 may include an active sensing portion 1307. The active sensing portion 1307 may face the electrochromic device 1300 in order to determine color information (e.g., color coordinates) of the electrochromic device 1300. The sunlight may be transmitted through the electrochromic device 1300 or refracted through the electrochromic device 1300 and received by the color sensor 1305. The active sensing portion 1307 can determine the color transmitted or refracted from the electrochromic device 1300. The color of the electrochromic film may include a transmissive color.

Fig. 14 is a graph showing an exemplary relationship between a change in color of an exemplary electrochromic device and a change in transmittance from a transparent state to a dark state at a constant current. Fig. 14 depicts the relationship between the color coordinates or color dimension in the Lab color space and the transmission state, represented by (a, b). For example, starting point 1402 represents a color coordinate or color dimension of the electrochromic device when the electrochromic device is in a transparent state or a state having full or near full transmissivity. Starting point 1402 indicates that the color of the electrochromic device in the transparent state mixes green, red, yellow, and blue, with green being more than red and blue being more than yellow. As the electrochromic device transitions from the transparent state to the dark state, the amount of green and blue increases, while the amount of red and yellow decreases, in a first phase 1406 up to a second point 1407. In some embodiments, the first stage 1406 extends between the starting point 1402 and the second point 1407. In some embodiments, the second stage 1408 extends between the second point 1407 and the third point 1409. During the second phase 1408, the amount of green and yellow increases, while the amount of blue and red decreases. In some embodiments, the third stage 1410 extends between a third point 1409 and a fourth point 1411. During the third stage 1410, the amount of red and yellow increases, while the amount of green and blue decreases. In some embodiments, the fourth stage 1412 extends between the fourth point 1411 and the endpoint 1404. During the fourth phase 1412, the amounts of blue and red increase, while the amounts of green and yellow decrease. Endpoint 1404 represents a color coordinate or color dimension of the electrochromic device when the electrochromic device is in a dark state or a state with little to no transmission. In some embodiments, the relationship between color coordinates or color dimensions and transmission states in the Lab color space may be based on the level of electrochromic cycling, or the level or electrochromic degradation due to electrochromic cycling. For example, based on the level of electrochromic cycling, the color coordinates in the transparent state or the color coordinates in the dark state may be changed.

If the electrochromic device is transitioning from a dark state to a light state (e.g., from endpoint 1404 to start 1402), the relationship between the color coordinates or color dimension and the transmissive state may be reversed, as the electrochromic device may sequentially pass through the fourth stage 1412, the third stage 1410, the second stage 1408, and the first stage 1406. In some examples, the color coordinate change of the electrochromic device may exhibit a hysteresis effect when transitioning between the dark state and the light state as compared to the color coordinate change of the electrochromic device transitioning between the light state and the dark state.

In some embodiments, a controller, such as controller 1205 or controller 1305, may use information of the transmittance state of the electrochromic device to determine the current color coordinates of the electrochromic device (e.g., 1200 or 1300). For example, the controller may determine the location on a map corresponding to the transmission state (e.g., the map depicting relationship 1400 of fig. 14) and determine the current color coordinates in lab coordinates according to the state of transmissivity. For example, the controller may determine that the transmission state corresponds to the first stage 1406 or a point within the first stage 1406, and determine corresponding color coordinates based on the transmission state.

In some embodiments, the spectrometer and/or tri-color source colorimeter may simultaneously determine the color and the level of transmittance or transmission state, respectively, of the electrochromic device. The spectrometer can determine the spectral power distribution of light intensity over a range of wavelengths. A spectrometer or tri-source colorimeter may determine color information by integrating the spectral power distribution with the CIE color matching functions. The spectrometer or tri-source colorimeter may convert the obtained color coordinates (x, y) into a (u, v) or lab color space.

Fig. 15 shows an exemplary tri-color source colorimeter 1500. The three-color-source colorimeter 1500 may include a color filter 1502 and a photodetector 1504 coupled to the color filters, respectively. The color filter 1502 may include a blue color filter, a green color filter, and a red color filter. The photodetector 1504 may determine the light intensity of each of the respective color filters 1502. The photodetector 1504 may include a silicon diode.

Fig. 16 is a diagram illustrating an electrochromic device 1600 (e.g., a smart window) consistent with example embodiments of the present disclosure. The electrochromic device 1600 may include two glass layers 1601, two adhesive layers 1602, an electrochromic film 1603, one or more electrical wires 1604, a controller 1605, and a solar cell 1606 integrated into the electrochromic device 1600. In some embodiments, the solar cell 1606 may be configured to supply energy to the controller 1605 by converting harvested solar energy to electrical energy. In some examples, the converted electrical energy may be stored in an electrical energy storage unit, such as a battery or a capacitor. The solar cell 1606 may also simultaneously detect light intensity in addition to generating energy. In some embodiments, the solar cell 1606 may detect light intensity based on the amount of current generated by the solar cell 1606. In some examples, the solar cell 1606 may detect light intensity based on a relationship between the generated current and light intensity and/or based on a predetermined relationship between the generated current and light intensity. In some embodiments, the current generated by the solar cell is linearly dependent on the light intensity. In some examples, the solar cell 1606 may send information of light intensity or a signal indicating light intensity to the controller 1605.

For example, when the amount of converted electric energy generated by the solar cell 1606 is insufficient to operate the controller 1605, the controller 1605 may consume the electric energy stored in the electric energy storage unit. In response to receiving information of the light intensity or a signal indicative of the light intensity, the controller 1605 may adjust the transmission state and/or color of the electrochromic device 1600 by injecting or extracting an amount of power to the electrochromic device 1600. In some examples, controller 1605 may adjust the transmission level to be inversely proportional to the light intensity detected by solar cell 1606. If the detected light intensity increases, the controller 1605 can decrease the level of transmission through the electrochromic device 1600. If the detected light intensity decreases, the controller 1605 can increase the level of transmission through the electrochromic device 1600.

The controller 1605 may be further configured to monitor and adjust the color of the electrochromic device 1600, similar to the implementation of the controller 1205 described with respect to fig. 12A. In some embodiments, the controller 1605 can be laminated between two glass layers 1601.

Two glass layers 1601 may be implemented as two glass layers 1201 of fig. 12A. The two adhesive layers 1602 may be implemented as the two adhesive layers 1202 of fig. 12A. The electrochromic film 1603 may be implemented as the electrochromic film 1603 of fig. 12A. The one or more wires 1604 may be implemented as one or more wires 1204 of fig. 12A.

Figures 17-18 are diagrams illustrating a stand-alone and self-powered controller powered by an energy generator such as a solar cell. In fig. 17, an energy generator, such as a solar cell 1706, may supply electrical energy to a controller 1705. The solar cell 1706 may be implemented as the solar cell 1606 of fig. 16. The controller 1705 may be implemented as the controller 1605 of fig. 16. As shown in fig. 17, the controller 1705 may include a power storage unit 1701, a power converter 1702, a power output controller 1703, and a signal receiver 1704. The electrical energy storage unit 1701 may be a battery or a capacitor. The power converter 1702 may convert input power from the power storage unit 1701 into power required or available by the signal receiver 1704 and the power output controller 1703. Accordingly, in some embodiments, the power output controller 1703 and the signal receiver 1704 may receive power indirectly from the solar cell 1706. The amount of electrical energy received by the electrical energy output controller 1703 and the signal receiver 1704 may not be completely dependent on the amount of light captured by the solar cell 1706. The power output controller 1703 may be configured to power an electrochromic device, such as electrochromic device 1600, for example, in response to information from the signal receiver 1704. The signal receiver 1704 may be configured to receive information or signals indicative of the detected light intensity, the transmission level of the electrochromic device, and/or the color of the electrochromic device. Similar to the mechanism implemented in FIG. 16, the power output controller may be configured to provide an amount of power based on information from the signal receiver 1704 or a signal received from the signal receiver 1704. In some embodiments, the active light receiving portion of the solar cell 1706 faces a light source, such as sunlight. In some embodiments, the solar cell 1706 may determine an angle of incidence of light impinging on an active light-receiving portion of the solar cell 1706. For example, when the incident angle of light is 90 degrees, the solar cell 1706 may adjust its orientation with respect to the light source to maximize the amount of light irradiated to the active light receiving portion of the solar cell 1706.

In fig. 18, an energy generator, such as a solar cell 1806, may supply electrical energy to the controller 1805. The solar cell 1806 may be implemented as the solar cell 1606 of fig. 16. In some embodiments, the solar cell 1806 may generate electrical energy while determining the light intensity. In some embodiments, the solar cell 1806 may detect light intensity based on the amount of current generated by the solar cell 1806. In some examples, the solar cell 1606 may detect light intensity based on a relationship between the generated current and light intensity and/or based on a predetermined relationship between the generated current and light intensity. In some embodiments, the current generated by the solar cell is linearly dependent on the light intensity. In some examples, the solar cell 1806 may send information of the light intensity or a signal indicative of the light intensity to the controller 1805, specifically to a signal receiver, such as the signal receiver 1804, as described below.

The controller 1805 may be implemented as the controller 1605 of fig. 16. As shown in fig. 18, the controller 1805 may include an electrical energy storage unit 1801, a power converter 1802, a power output controller 1803, and a signal receiver 1804. The electrical energy storage unit 1801 may be a battery or a capacitor to receive stored electrical energy from the solar cell 1806, while the solar cell 1806 sends information of the light intensity or a signal indicative of the light intensity to the signal receiver 1804. The power converter 1802 may convert input power from the power storage unit 1801 to power needed or available to the signal receiver 1804 and the power output controller 1803. Thus, in some embodiments, the power output controller 1803 and the signal receiver 1804 may receive power indirectly from the solar cell 1806. The amount of electrical energy received by the electrical energy output controller 1803 and the signal receiver 1804 may not be completely dependent on the amount of light captured by the solar cell 1806. The power output controller 1803 may be configured to power an electrochromic device, such as the electrochromic device 1600, for example, in response to information from the signal receiver 1804. The signal receiver 1804 may be configured to receive information or signals indicative of the detected light intensity, the transmission level of the electrochromic device, and/or the color of the electrochromic device. In some embodiments, the signal receiver 1804 determines an amount of power to be provided to the electrochromic device based on the current generated by the solar cell 1806 or the current density transmitted from the solar cell 1806 to the signal receiver 1804. In some embodiments, the signal receiver 1804 may transmit the determined amount of power to the power output controller 1805. Similar to the mechanism implemented in fig. 16, the power output controller 1805 may be configured to provide an amount of power based on information of the signal receiver 1804 or a signal received from the signal receiver. In some embodiments, the active light receiving portion of the solar cell 1806 faces a light source, such as sunlight. In some embodiments, the solar cell 1806 may determine an angle of incidence of light impinging on an active light receiving portion of the solar cell 1806. For example, when the incident angle of light is 90 degrees, the solar cell 1806 may adjust its orientation with respect to the light source to maximize the amount of light irradiated to the active light receiving part of the solar cell 1806.

In this disclosure, we propose a method of changing the optical state of an electrochromic material by constant voltage driving and constant current driving. It should also be well understood that combinations of voltage and current drives, pulsed voltage and pulsed current drives, pulsed and DC drives, and the like can also be employed to change the electrochromic material to the desired optical state. As long as a certain amount of charge is injected into or extracted from the electrochromic material, the optical state of the electrochromic material can be adjusted accordingly.

The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments. Many modifications and variations will be apparent to practitioners skilled in the art. Such modifications and variations include any relevant combination of the features disclosed. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.

Claims

1. A method of changing an optical state of an electrochromic film in an electrochromic device, comprising:

determining the color of the electrochromic film;

determining an amount of adjustment to apply to the color; and

controlling the amount of charge injected into and removed from the electrochromic film according to the determined adjustment amount.

2. The method of claim 1, wherein determining an adjustment amount to apply to the color further comprises:

determining a difference between the color of the electrochromic film and a target color.

3. The method of claim 2, wherein the target color is a color of an electrochromic film in another electrochromic device in the same room, house, building, or residence.

4. The method of claim 3, wherein the target color is preset to the same color for all electrochromic films in other electrochromic devices in the same room, house, building, or residence.

5. The method of claim 2, wherein the target color is a color of the electrochromic film when the electrochromic film is in a dark state and an undegraded state.

6. The method of claim 2, wherein the target color is a color of the electrochromic film when the electrochromic film is in a bright state and an undegraded state.

7. The method of claim 2, wherein determining an adjustment amount to apply to the color further comprises:

determining whether the difference is greater than a threshold amount; and

in response to determining that the difference is greater than the threshold amount, injecting or removing charge in the electrochromic film until the difference is less than the threshold amount.

8. The method of claim 2, wherein controlling an amount of charge injected into and removed from the electrochromic film comprises injecting or removing an amount of charge determined to achieve the target color of the electrochromic film.

9. The method of claim 1, wherein determining the color of the electrochromic film comprises:

determining a transmission state of the electrochromic film; and

determining a color of the electrochromic film based on the determined transmission state and based on a relationship between the transmission state of the electrochromic film and the color of the electrochromic film.

10. The method of claim 9, wherein determining an adjustment amount to apply to the color further comprises:

determining an amount of adjustment to apply to the color based on a rate of change of the color relative to the change in transmission state.

11. The method of claim 1, wherein controlling an amount of charge injected into and removed from the electrochromic film comprises applying an external DC voltage to the electrochromic film.

12. The method of claim 1, wherein controlling the amount of charge injected into and removed from the electrochromic film comprises applying an external DC current to the electrochromic film.

13. The method of claim 1, wherein controlling an amount of charge injected into and removed from the electrochromic film comprises applying an external pulse voltage to the electrochromic film.

14. The method of claim 1, wherein controlling an amount of charge injected into and removed from the electrochromic film comprises applying an external pulsed current to the electrochromic film.

15. The method of claim 1, wherein the color of the electrochromic film comprises one or more of a reflective color and a transmissive color.

16. The method of claim 1, further comprising pre-installing the electrochromic device directly into a window frame.

17. A method of changing an optical state of an electrochromic film in an electrochromic device, comprising:

detecting the light intensity of external light; and

adjusting a level of transmission of the electrochromic film based on the detected light intensity or the detected change in light intensity.

18. The method of claim 17, further comprising:

detecting the light intensity while supplying power to the electrochromic device.

19. The method of claim 18, wherein the detecting light intensity comprises:

determining an amount of current generated during the supplying of the power; and

detecting the light intensity according to the determined amount of generated current.

20. The method of claim 19, wherein detecting the light intensity based on the determined amount of generated current comprises detecting the light intensity based on a linear relationship between the light intensity and the amount of generated current.