Optical modulator, substrate including electrode, and smart grazing

Abstract

To provide a substrate applied in accordance with lower diffraction, more uniform non-transparency state over a substrate and a more uniform transition rate, and an optical modulator including such an improved substrate.SOLUTION: Some embodiments relate to an optical modulator including a penetrable or reflexible substrate. A plurality of electrodes having a pattern over a substrate are applied to a substrate; and a controller can bring the motion of cataphoresis of particles toward the electrodes or from the electrodes and apply a potential to the electrodes for obtaining an electromagnetic field between the electrodes.SELECTED DRAWING: Figure 1a

Description

Technical Field

[0001] The subject matter of the present disclosure relates to optical modulators, substrates, optical modulator methods, and computer-readable media.

Background Art

[0002] In this technology, optically active grating is known. Typically, an optically active grating system includes two parallel plates made of a transmissive dielectric material such as glass or plastic material. The internal volume defined between the plates is subdivided into a plurality of independent small volumes or individual cells filled with a dielectric fluid. This fluid contains a suspension of particles of a dielectrically charged or chargeable material. The opposing surfaces of the two plates carry electrodes facing each other. These electrodes are connected to a power source associated with control means.

[0003] The electrodes of each plate are formed in a comb shape arranged alternately with each other in pairs. The two alternately arranged comb electrodes can take voltages of the same polarity or opposite polarities. When an appropriate voltage is applied to the electrodes, the particles can be collected at various locations between the electrodes in order to give the system either a transmissive or non-transmissive appearance.

[0004] There are various drawbacks associated with this known system. When the known grating is in its transmissive configuration, the electrodes applied to the plates cause a diffraction effect. The diffraction effect is not desirable for the grating. Depending on the situation, the presence of the diffraction effect may also be harmful to safety. For example, when optically active grating is applied to a vehicle such as an automobile, the presence of diffraction may be confusing or distracting to the vehicle operator.

[0005] Furthermore, the driving of this known system can be improved.

[0006] Another drawback of known systems is that in an opaque configuration, it is desirable for the glazing to appear uniform. This aspect can also affect safety. For example, if the glazing is configured to be intermediate between opaque and transparent, a lack of uniformity may cause it to be confusing or distracting. It is further desired that the transition proceed at a uniform rate across the glazing.

[0007] Another drawback of this known system is that the presence of physical contaminants can adversely affect device performance. For example, the presence of fine particles, fibers, stones, chunks, grains, etc. in a fluid can cause physical damage to the electrodes. Further, these contaminants may be conductive or may attract charge from the fluid on their surfaces and become conductive, thereby disrupting or short - circuiting the electric field between electrodes on the same substrate or different substrates. All of these contaminants in various capacitances can have an adverse effect on the optoelectronic performance of the system. Further, they can cause a disturbance in the desired current balance in the device, and as a result, may shorten the life of the device.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Non - Patent Documents

[0009]

Non - Patent Document 1

Summary of the Invention

Means for Solving the Problems

[0010] It would be beneficial to provide an improved substrate provided with electrodes and an optical modulator comprising such an improved substrate to address the above and other problems. The inventor has discovered that the electrode design in known systems results in diffraction and also results in an electric field that is not completely uniform. Addressing the first problem leads to a substrate that can be applied with lower diffraction, a more uniform opaque state across the substrate, and a more uniform transition rate. Addressing the second problem leads to a substrate that is less susceptible to the harmful effects of the presence of physical contaminants between substrates.

[0011] Optically active grading, particularly so-called smart grading, is an important application for transmissive or reflective substrates to which electrodes are applied. For example, transmissive or reflective substrates for applications such as these smart gradings can each have two electrodes having a plurality of main lines. These lines are arranged alternately on the substrate, and thus an electric field can be established between successive or adjacent lines by providing a potential difference to the electrodes.

[0012] A plurality of branch lines can extend from these main lines. By extending the branch lines by at least half the distance between two main lines, better homogeneity and / or a lower diffraction effect can be obtained. Further, two successive branch lines extending into the same area between the first main line and the second main line can overlap in a second direction when projected in a first direction. These branch lines increase the number of angles seen on the substrate, and accordingly reduce the diffraction effect. For example, an angle different from vertical may be selected and / or varied further to reduce diffraction. Diffraction can also be reduced by varying the distance between the main lines and successive main lines on the substrate.

[0013] The substrate according to the embodiment can be used in an optical modulator, also known as a light modulator. For example, two such substrates may be arranged facing each other, and thus, by applying a voltage to the electrodes, charged particles floating in the fluid between the substrates can be made movable. Typically, the electrode designs for the lower substrate and the upper substrate are the same, but this is not essential. Similarly, the two designs are typically aligned with each other, but this is also not essential. The particles may absorb light or reflect it. The reflection may be specular, diffusive, or intermediate. The particles may emit light having, for example, phosphorescence or fluorescence.

[0014] The optical modulator provides a panel whose transmittance or reflectance can be modified. In an embodiment, things such as color or color intensity may be changed. The optical modulator can be used as a cover, for example, as a cover of a container such as a closet, a cabinet, etc. The optical modulator is also called a ambient light modulator, a dynamic light modulator, an optical modulator, a color modulator, an IR modulator, a UV modulator, an IR active filter, a UV active filter, or a dynamic color filter according to a specific application.

[0015] A particularly beneficial application is in optical active glazing, and in this field, it is also called smart glazing, smart window, controllable glazing, optical panel, electronic signage, dynamic light panel, dynamic color panel, active color panel, active light panel, active light surface, active color surface, dynamic light surface, or dynamic color surface.

[0016] In an embodiment, the controller is configured to apply a potential to the electrodes on the substrate of the optical modulator in order to obtain an electromagnetic field between the electrodes. This electromagnetic field causes electrophoretic movement of particles towards or from the electrodes. When the particles change position, the optical properties of the panel, such as its transmittance or reflectance, change. If the particles are colored, the color of the panel can also change. By changing the pair of electrodes between which an electric field is established, the particles can be moved in a desired direction. The inventor has discovered that the control of the optical modulator need not be limited to only changing the electrodes to which an electric field is applied, but can also include changing the maximum amplitude. It should be noted that, advantageously, an alternating current is used. For example, the rate of change in the optical modulator is changed by driving with a lower maximum amplitude. This is beneficial because the maximum amplitude can be reduced to avoid overshoot when driving towards a desired target transmittance or reflectance, for example. The maximum amplitude can also, or instead, be increased when starting to drive towards the target transmittance or reflectance. For example, by using an alternating current or alternating voltage of one of a plurality of maximum amplitudes, the controller can be configured to obtain one of a plurality of levels of transmissivity or reflectivity in the optical modulator. This relationship can be represented by an algorithm or the like. The relationship between the level of transmissivity or reflectivity and the maximum amplitude can be managed, for example, by a look-up table showing a series of maximum amplitudes for driving towards a transmittance or reflectance. It should be noted that an alternating voltage is also possible.

[0017] In addition to changing the electrodes to which a signal is applied, changing the maximum amplitude of the drive signal can also be used to improve balanced driving. For example, the power applied on some electrodes, such as the maximum amplitude, may be different from that applied to other electrodes. For example, the controller may be configured to apply a potential difference between successive electrodes on the same substrate and, at the same time, apply a potential difference between opposing electrodes on the opposing substrate.

[0018] In an embodiment, at least two electrodes are present on each substrate, but more than two electrodes may be present. For example, at least three electrodes may be applied to at least one of the first substrate and the second substrate. For example, in an embodiment, two electrodes may be applied to the first substrate and three electrodes may be applied to the second substrate.

[0019] A system in which one substrate has at least two electrodes and the other substrate has at least three electrodes has various advantages. For example, such a modulator may be driven so that the so-called curtain effect is reduced. This curtain effect occurs while the window is closed and appears as if a curtain is being drawn between the electrodes. This curtain effect is itself a visual distraction and also increases diffraction, so it is a drawback. On the side with three electrodes, the electrodes can be brought closer together than on the two-electrode side, for example, less than 50 microns, more preferably less than 40 microns, for example, both can be brought closer together to 35 microns. This means that the electric field is stronger. Accordingly, it closes faster and the curtain effect is reduced. When the 2+2 panel is moved so that the electrodes are brought closer together, it can lead to a reduction in the maximum transmittance or reflectance. However, this can be avoided if additional electrodes are available. When open, some of the additional electrodes may be unused, so the loss of maximum transmittance or reflectance is small. Additional electrodes on the substrate, for example, more than two electrodes, can be configured to attract particles when the panel is closed but not when the panel is open. For example, a panel in which each substrate has at least two electrodes can have a total of at least four electrodes. The substrates in the panel can have at least five electrodes, for example, in a 2+3 design; or at least six electrodes, for example, in a 2+4 or 3+3 design; or at least eight electrodes, for example, in a 4+4 design, or as two 2+2 designs stacked together using three substrates, with the middle substrate having two electrodes on each side.

[0020] The first substrate and the second substrate are arranged such that their inner sides face each other, and a plurality of electrodes are applied to the inner sides of the first substrate and the second substrate, respectively. Therefore, each of the first substrate and the second substrate has an inner surface, whereby a part of the inner surface of each substrate is provided with a plurality of electrodes, and a part of this surface is in fluid contact with a fluid containing particles but without electrodes provided thereon. Thus, the inner sides of the first substrate and the second substrate each have a specific inner surface area, i.e., the total surface area occupied by the electrodes and the surface area of the inner surface not occupied by the electrodes. At least a part of the inner surface area of at least one of the first substrate and the second substrate is provided with a protective coating. This protective coating prevents direct contact between contaminants such as fine particles, fibers, stones, lumps, grains, etc. present in the liquid and the electrodes. These contaminants can be formed in various ways such as aggregation of smaller particles, static electricity, and entrapment between electrodes. The contaminants may cause a short circuit between electrodes on the opposing substrates or between adjacent electrodes on the same substrate, and may also cause physical damage to the electrodes themselves or any combination thereof.

[0021] Therefore, in an embodiment, the protective coating at least partially or completely prevents such contaminants from causing physical damage to the electrodes. In an embodiment, the protective coating at least partially or completely prevents such contaminants from causing a short circuit between the electrodes. In one embodiment, the protective coating prevents both physical damage to the electrodes and a short circuit between the electrodes.

[0022] The protective coating does not essentially contribute to the basic operation of the technology and thus does not require electrical or optical properties particularly linked to the electrode design and device operation as described herein. To prevent a short circuit between the electrodes, the protective coating does not conduct most of the charges or is electrically insulating. Thus, in an embodiment, the protective coating forms an electrically insulating layer between at least some of the electrodes. In an embodiment, the protective coating has at least 10 7 Ωm, preferably at least 109 Ωm, more preferably at least 10 10 Ωm, even more preferably at least 10 11 Ωm. As used herein, the term "electrically insulating" should be considered synonymous with "no electric conduction", or simply "non-conductive" or "non-conducting".

[0023] Such an electrically insulating layer can typically also form a mechanical barrier layer nearby and / or can also reduce physical damage to the electrodes for the electrodes. Thus, in an embodiment, the protective coating forms an electrically insulating layer and a mechanical barrier layer between contaminants present in the optical layer and at least a part of the electrodes. However, it is also possible that the protective coating only provides protection against mechanical damage to the electrodes. Thus, in an embodiment, the protective coating forms only a mechanical barrier layer. The protective coating may be provided on at least one of the first substrate and the second substrate, or only on one of the first substrate and the second substrate, or at least a part of the inner surface areas of both. The coating can be applied to substantially or simply one or more areas where electrodes are provided, substantially or simply one or more areas where no electrodes are provided, or a combination thereof. Typically, at least a part of the inner surface area of at least one of the first substrate and the second substrate to which the electrodes are applied is provided with the protective coating. However, in some embodiments, the protective coating is provided almost exclusively on those portions of the inner surface of at least one of the substrates where no electrodes are provided.

[0024] The coating may be provided on at least a part of the surface area of the plurality of electrodes, and may be provided on at least a part of the electrodes on only one substrate or on both substrates. For example, only one substrate may be provided with a protective coating that covers at least a part of the electrodes applied to the substrate, while the opposing substrate does not include a protective coating covering the electrodes nor a protective coating covering the substrate portion where no electrodes are applied. Thus, in an embodiment, the protective coating is provided on at least a part of the surface area of the plurality of electrodes on one of the first substrate and the second substrate, and no protective coating is provided for the opposing substrate.

[0025] In another example, both substrates may be provided with a protective coating that covers at least a part of the inner surface of the substrate. Thereby, in an embodiment, the protective coating is provided on at least a part of the surface area of the inner surfaces of both the first substrate and the second substrate.

[0026] The protective coating may cover a portion of the total surface area of the electrodes on the inner side of the substrate by, for example, a continuous, preferably homogeneous coating that substantially covers the entire inner side of the substrate and a plurality of electrodes applied to the inner side of the substrate, may cover a portion of the total surface area of the inner side of the substrate not covered by the electrodes, or may cover substantially all of the inner surface area of the substrate. In embodiments, the protective coating covers at least a total of 1%, preferably at least 10%, more preferably at least 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the total inner surface area of the substrate. In embodiments, the protective coating covers at least a total of 1%, preferably at least 10%, more preferably at least 20, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the total surface area of the plurality of electrodes on the substrate. This total coated area may be distributed across the entire surface area occupied by the electrodes. The protective coating may be provided primarily on the area of the substrate covered by the electrodes, or only on the area of the substrate covered by the electrodes, or primarily on the area not covered by the electrodes, or only on the area not covered by the electrodes.

[0027] The protective coating may cover substantially all or the entire surface area of at least one of the first substrate and the second substrate such that the protective coating is provided on both the electrodes applied on the substrate and the inner surface of the substrate where no electrode is applied. For example, the protective coating may be a continuous, preferably homogeneous coating that protects substantially all or all of the electrodes applied inside the substrate from physical damage and / or short circuits. Such an overall protective coating may be provided inside at least one of the first substrate and the second substrate. Such an overall protective coating may also be provided only inside one of the first substrate and the second substrate, but the opposing substrate and the electrodes applied thereto are not provided with the protective coating. Thus, in an embodiment, the inner side of one of the first substrate and the second substrate is provided with an overall protective coating such that substantially the entire surface of the plurality of electrodes applied inside and the inner side of the substrate where no electrode is provided are covered with the protective coating, and the opposing substrate is not provided with the protective coating. Such an overall protective coating may also be provided inside both the first substrate and the second substrate. Thus, in an embodiment, substantially the entire inner side, i.e., the entire inner surface area, of both the first substrate and the second substrate is provided with an overall protective coating such that substantially the entire surface of the plurality of electrodes applied inside and the inner side of the substrate where no electrode is provided are covered with the protective coating.

[0028] The thickness of the protective coating can vary significantly. Typically, the protective coating has a thickness in the range of 1 nm to 100 μm, preferably in the range of 10 nm to 50 μm, preferably in the range of 100 nm to 10 μm. The appropriate lower limit of the thickness of the protective coating is determined, inter alia, by the degree of electrical insulation required and, as a result, depends on the potential difference applied to the electrodes and the expected conductivity of the contaminants. The preferred upper limit of the thickness of the protective coating is mainly determined by the minimum distance between the electrodes on the opposing substrate and is typically less than 500 microns, such as less than 30 μm, preferably less than 200 μm, preferably less than 100 μm, and more preferably less than 50 μm.

[0029] The selection of a suitable thickness of the protective layer is further determined by the extent of the coating coverage applied to the first and / or second substrate. More specifically, whether a continuous, preferably homogeneous protective coating is applied or an intermittent discontinuous coating as described below contributes to determining the minimum thickness necessary to achieve the desired effect of preventing short circuits and / or physical damage to the electrodes.

[0030] The protective coating may be applied in a discontinuous form where not all surfaces of the electrodes and not all surfaces inside the substrate are covered by the protective coating. This discontinuous form of the coating may have a random pattern or may form a regular pattern, which may be selected for a particular predetermined effect on the optoelectronic performance of the device.

[0031] In an embodiment, the protective coating is provided as a patterned coating. Such a patterned coating can be applied to the side of the substrate having the electrodes using a mask known in the art.

[0032] This pattern can be applied such that some electrodes are provided with the protective coating and other electrodes are not provided with the protective coating and are in fluid-to-fluid contact. In an embodiment, the first main line on the first substrate is provided with the protective coating, the second main line on the second substrate facing the first main line is not coated, and the second main line is in fluid-to-fluid contact, or vice versa. The pattern can be a regular pattern in which the electrode surfaces are alternately covered with the protective coating. In an embodiment, a plurality of main lines on the first substrate and the second substrate have the protective coating provided alternately and not provided.

[0033] The pattern is not limited to a one-dimensional pattern. For example, the protective layer can take the form of a mesh or a web, and optionally can have the form of a random web or a random mesh. Such a protective coating in the form of a web or a mesh may be similar for both substrates and / or may be aligned in direction and position, but this is not essential.

[0034] The above-described combinations of patterns are possible both within the same substrate and with respect to opposing substrates. For example, the inside of the first substrate may be provided with an overall protective coating that substantially covers all the electrodes and the inside of the substrate where no electrodes are provided, and the opposing substrate may not be provided with a coating. In an embodiment, the coated pattern is provided on at least a part of the inside of one of the first substrate and the second substrate (thus covering part of the electrodes and optionally part of the substrate where no electrodes are provided), but is not provided on the opposing substrate. In an embodiment, at least a part of a plurality of electrodes applied inside and / or at least a part of the inside of the substrate where no electrodes are provided are provided with a coating, and the coating is provided in a random pattern on the inside of at least one of the first substrate and the second substrate such that at least a part of a plurality of electrodes applied inside and the inside of the substrate where no electrodes are provided are not provided with a coating.

[0035] It is not necessary for the protective coatings on the substrates to be aligned with each other. However, for example, a discontinuous protective coating such as a mesh can be applied on both substrates where the main lines of those meshes form an angle with each other, for example, at an angle of 15 degrees, 30 degrees, or 45 degrees. In another example, the protective coating is applied in the form of parallel lines on both substrates, whereby the parallel lines on one of the two substrates are rotated 90 degrees with respect to the parallel lines on the opposing substrate. Thus, the mesh-type pattern of the protective coating can be created by a combination of line patterns on the opposing substrates.

[0036] In an exemplary embodiment, when at least one of the substrates is entirely provided with a protective coating, i.e., substantially, the entire surface of a plurality of electrodes and the inside of the substrate where no electrode is provided are preferably covered with the protective coating substantially homogeneously, a protective coating having a thickness in the range of less than 10 nm is used. In an exemplary embodiment, a protective coating having a thickness of 1 micron or more is suitable for a coating applied as a discontinuous layer to at least a part of only the electrodes, at least a part of only the inner surface of the substrate where no electrode is provided, or a combination thereof, regardless of whether it has a specific pattern. In an exemplary embodiment, a protective coating having a medium thickness, i.e., a thickness in the range of 10 nm - 1 micron, can be used both as an overall continuous coating and as a discontinuous coating.

[0037] As mentioned above, the protective coating may be provided uniformly across the inner surface area of the substrate or may be patterned for a specific area. In other words, this protective coating does not necessarily have to be completely continuous, and inherent gaps, micropores, cavities, etc. can be tolerated as long as their size and distribution are significantly smaller than those of larger physical contaminants. Thus, such gaps can be tolerated in the protective coating as long as the maximum dimension of the gap does not exceed the minimum distance between two electrodes on the substrate so that the coating has the intended protective effect.

[0038] Similarly, the size of the contaminants that are still tolerated is determined by the electrode design or pattern, by the distance between electrodes on the same substrate, and by the distance between electrodes on opposing substrates. Thus, the quality and continuity of the protective layer are determined by the need to statistically limit or remove the influence of those contaminants on the appearance and performance of the device. As an example, it may be required that the protective layer can tolerate gaps in a protective coating that extends up to a maximum of 90% of the minimum distance between separate electrodes on the same substrate or opposing substrates, i.e., the minimum distance between the electrodes of the same substrate and the cell gap of the device.

[0039] This protective coating can be made from a wide variety of materials and combinations of materials, and one skilled in the art can select a suitable material that meets the requirements described above with respect to protection against physical damage and short circuits, as well as coating thickness, homogeneity, device driving methods, etc. Suitable materials include, for example, inorganic materials and compositions such as silicon nitride, silicon dioxide, silicon oxynitride, polysilicon, amorphous silicon, aluminum oxide, tantalum pentoxide, and zirconium dioxide, and combinations thereof, as well as organic or polymeric materials including, but not limited to, polyimide, fluoropolymers, silicone resins, polytetrafluoroethylene, polyimide resins, photoresists, epoxy resins, and benzocyclobutene-based polymers, and combinations thereof. Combinations of these inorganic materials and compositions, as well as organic and / or polymeric materials are also possible. The protective coating material may be hard or non-hard. In an exemplary embodiment, the protective coating material is non-hard.

[0040] Depending on the selected application and coating thickness, the protective coating can be transmissive, semi-transmissive, or reflective for a specific color or over a broad wavelength range. In some embodiments, the protective coating is a transmissive or semi-transmissive coating. In some embodiments, the protective coating is a reflective coating. Combinations of transmissive, semi-transmissive, and / or reflective portions of the coating on the same substrate or on opposing substrates are also possible. In some embodiments, the protective coating provides an additional optical function to the device. In some embodiments, this is an independent optical function. In some embodiments, this is an optical function that cooperates with the electro-optical effect of the device. These can be, for example, reflection effects, anti-reflection effects, diffusion effects, and / or anti-diffraction effects for all optical wavelengths or for a portion of the electromagnetic spectrum such as UV, visible, and / or IR.

[0041] The protective coating material can be selected to have a refractive index that is sufficiently different from the refractive index of the fluid solvent in order to produce significant light refraction. For example, a protective coating made of silicon nitride having a refractive index of 3 can be combined with a fluid solvent having a refractive index of less than 2. The difference in refractive index induces a change in the direction of the incident light refraction and the light direction according to Snell's law. Thus, the optical modulator can direct the incident light in a specific designed direction. This effect can be combined with the specific shape and topography of the patterned protective coating in order to refract light in multiple directions and thus increase light diffusion or haze. Similarly, different protective coatings from the same substrate or from different substrates are possible for enhancing a specific optical path or diffusion.

[0042] The difference between the refractive index of the substrate and the refractive index of the fluid containing the particles produces light reflection. Introducing a protective coating made of a material exhibiting an intermediate refractive index, whether patterned or unpatterned, limits the back reflection and thus produces an anti-reflection coating. Similarly, combinations of various protective coatings on one or all substrates can lead to minimizing the back reflection of the incident light or improving the internal reflection. Here, light should be considered across the entire optical spectrum or a portion thereof, such as the ultraviolet, visible or infrared spectra, or combinations thereof.

[0043] The protective coating material can also absorb light in the visible range, such as absorbing all visible light and appearing black. The shape and position of the protective coating on one or more substrates can induce light diffraction. The addition of such a protective coating can enhance the diffraction pattern already induced by the substrate design or device design, while adding new diffraction directions to the light, causing an increase in the scattering effect and blurring. Here, a black protective coating layer is exemplified, but it can be applied to other types of light absorption dedicated to a specific diffracted system, including but not limited to the ultraviolet or infrared wavelength ranges. Furthermore, the addition of specific patterns, shapes, and optical properties of the protective coating on one or more substrates can weaken the light diffraction initially induced by the substrate or device in order to refocus the incident light back in its original direction. Incorporating such a coating layer into a device enhances the ability to recover light diffraction and thus demonstrate an anti-diffraction effect.

[0044] Depending on the selected material or combination of materials, the protective coating can be applied using a variety of techniques known in the art, such as sputtering, molecular beam epitaxy, pulsed laser deposition, electron beam evaporation, chemical vapor deposition, atomic layer deposition, spin coating, flexographic printing coating, dip coating, spray-coating, inkjet printing, slit coating, and combinations thereof.

[0045] The protective coating can be applied using a reflow process step that enables a more homogeneous formation of the protective coating on both the electrode and the remaining inner surface of the substrate not covered by the electrode. For example, the reflow process can be added after the deposition of the coating, optionally after patterning, resulting in a homogenization of the protective coating and an improved conformity with the topography of the substrate. Typically, the reflow process is a thermal process that can be performed in various ways, including oven heating, hot plates, infrared irradiation, laser irradiation, microwave irradiation, infrared conveyors, and combinations thereof. Chemical reflow processes can also be performed in the case of protective coatings made of organic materials or protective coatings containing organic materials, for example, by expanding the coating using solvent vapor or immersion.

[0046] In embodiments, this protective coating is a single layer. In embodiments, the protective coating is a multi-layer protective coating. In some embodiments, the multi-layer protective coating may include alternating layers of different material compositions. For example, a combination of protective coatings including a polymer layer deposited on an inorganic layer is possible. A single substrate may also include a plurality of protective layers of different materials, compositions, and dimensions.

[0047] The materials used for the protective coating may vary between substrates, or a plurality of protective coatings made of different materials may be provided on the same substrate.

[0048] A further aspect of the present invention is a building comprising an optical modulator according to an embodiment. A further aspect of the present invention is an automobile comprising an optical modulator according to an embodiment. For example, the automobile and / or the building may comprise an optical modulator and a controller configured to control the transmittance or reflectance of the optical modulator by controlling the voltage on the electrodes of the optical modulator, and the controller is electrically connected to or connectable to the optical modulator.

[0049] Smart grading is an electronic device and can be driven by a power source under the control of, for example, a controller. For example, the controller can instruct the power source to apply a specific waveform to a specific electrode to achieve various transmission or reflection effects, or the absence thereof.

[0050] Embodiments of this method may be implemented on a computer as a computer-implemented method, or may be implemented in dedicated hardware, or a combination of both. The executable code of embodiments of this method may be stored in a computer program product. Examples of computer program products include memory devices, optical storage devices, integrated circuits, servers, online software, etc. Preferably, the computer program product includes non-transitory program code stored on a computer-readable medium for performing embodiments of this method when the program product is executed on a computer.

[0051] In an embodiment, the computer program includes computer program code configured to perform all or part of the steps of embodiments of this method when the computer program is run on a computer. Preferably, the computer program is embodied on a computer-readable medium.

[0052] Further details, aspects, and embodiments are described by way of example only with reference to the drawings. The elements in the figures are illustrated to be simplified and clarified and are not necessarily drawn to scale. In the figures, elements corresponding to those already described may have the same reference numerals. The drawings include the following.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0054] List of reference numerals The following list of reference symbols and abbreviations is provided to facilitate the interpretation of the figures and is not to be construed as limiting the scope of the claims. 10 Optical modulator 11 First substrate 12 Second substrate 13, 13a, 13b Electrodes 14, 14a, 14b Electrodes 15 Fluid 16 Controller 30 Particles 20 Vehicle 21 Optical modulator 40 Optical modulator 41 First substrate 42 Second substrate 43 Third substrate 46 Controller 100 Substrate 101 First direction 102 Second direction 110 First electrode 120 Second electrode 111 - 113 Main lines 121 - 123 Main lines 131 - 134 Branch lines 141 - 144 Branch lines 150 Area 151 Half of the distance between two consecutive main lines 152 Distance between two consecutive branch lines 153 Distance between two consecutive main lines 161 Projection 162 Virtual line 171 - 174 Substrate 200 Substrate 201 - 206 Main line 251 - 253 Distance between consecutive main lines 221 First part 222 Connection part 223 Second part 231 Line spacing 232 Distance 300 Substrate 301 Main line 310, 320 Sub - main line 311 Connection 321, 322 Sub - main line 400 Substrate 410, 420 Main line 411, 412 Branch line 421, 422 Branch line 450 Substrate 451 - 454 Block

[0055] The subject matter of the present disclosure can have many different forms of embodiments. One or more specific embodiments are shown in the drawings and described in detail herein. The present disclosure is considered as an example of the principles of the subject matter of the present disclosure and is not intended to be limited to the specific embodiments shown and described. This understanding is accompanied by the fact that the present disclosure is not limited to only the embodiments, but also includes other combinations of the features described herein or in the respective dependent claims that are different from each other.

[0056] In the following, for the sake of understanding, the elements of the embodiments are described in terms of their operations. However, it is clear that each element is configured to perform the functions described as being performed by them. Furthermore, the subject matter disclosed herein is not limited to only the embodiments, but also includes other combinations of the features described herein or in the respective dependent claims that are different from each other.

[0057] Figure 1a is a diagram schematically showing an example of an embodiment of a substrate 100. There are at least two electrodes arranged in a pattern across the surface of the substrate 100. In Figure 1a, two electrodes on the same surface are shown: a first electrode 110 and a second electrode 120. For example, to facilitate finer control, there may be more than two electrodes on the same side of the substrate. For example, a plurality of electrodes can be used to facilitate a segmented substrate, for example, for a segmented optical modulator. For example, in a segmented optical modulator, some zones may have different optical properties, such as different transmittances or reflectances. Hereinafter, an embodiment having two electrodes is shown, but additional electrodes can be added to these two electrodes, for example, by replicating similar structures adjacent to each other.

[0058] The first electrode 110 and the second electrode 120 are applied to the same side of the substrate. These two electrodes are arranged in a pattern across the substrate. For example, one, two, or more electrodes may be present on the other surface of the substrate 100 to facilitate the stacking of three or more substrates. Applying the electrodes to the substrate can be done by lithography, for example, using a mask representing the electrode pattern. The electrodes can be applied by embedding them in the substrate.

[0059] The first electrode 110 and the second electrode 120 each include a plurality of main lines. As shown in Figure 1a, the first electrode 110 includes main lines 111, 112, and 113, and the second electrode 120 includes main lines 121, 122, and 123. Typically, each electrode includes more than three lines. The main lines extend across the substrate. The plurality of main lines of the first and second electrodes are arranged alternately with respect to each other on the substrate. The main lines extend across the substrate in a first direction 101. When viewed in a second direction 102, the main lines are alternately encountered from different ones, for example, from the first and second pluralities in the first and second electrodes, respectively. The first and second directions are angled with respect to each other, and typically, the angle is approximately perpendicular. The first and second directions may each be parallel to the side of the substrate, but this is not essential.

[0060] Desirable applications for substrates such as substrate 100 are in smart glazing, such as for optical modulators, and can be applied in homes, offices, greenhouses, automobiles, etc. The level of transmissivity or reflectivity of the smart glazing can be electrically configured. For example, in smart glazing, two substrates such as substrate 100 may be laminated, whereby the sides to which two electrodes are applied face each other. A fluid having particles is enclosed between the two substrates. Embodiments of smart glazing are further described below. In an embodiment, electrodes, for example, two or more electrodes are applied to one surface of each substrate. For example, one, two, or more electrodes may be present on the other surface of substrate 100 to facilitate stacking of three or more substrates.

[0061] Some of the following embodiments show examples of modulating the transmissivity level or reflectivity level. The optical modulator can be configured for other optical effects. For example, if necessary, the embodiment can be modified to different light transmissivity levels instead of different transmissivity levels. If necessary, the types of particles that can be used in the embodiment can be changed according to, for example, particles having different absorption or reflection wavelengths and according to how specular or diffuse their reflection is. For example, in an embodiment, the optical modulator can modulate different reflection levels. The particles may also emit light. Stacking multiple optical layers further increases the possibilities.

[0062] Having two sets of alternating main lines is sufficient to provide electrically compatible glazing; for these two alternating sets, the electric field of any part of the substrate can be controlled such that two opposing electrodes border the part from two opposing sides.

[0063] FIG. 1b is a diagram schematically showing an example of an embodiment of substrate 100. Two of the main lines of substrate 100 are shown in FIG. 1b. Main line 121 and main line 112 are shown. These main lines run across the main part of the substrate and may, for example, extend across substantially the entire substrate.

[0064] By conforming the shape of the electrodes, undesirable diffraction effects can be varied. For example, in the case of a reflective display such as can be applied to an e-book reader, the effect is not significant, so reducing the diffraction effect is particularly important in the case of a transmissive substrate. The inventor has found that in order to spatially spread out the diffraction, the diffraction of light may be reduced by orienting the linear shape of the electrodes at a plurality of different angles, and thus reducing the brightness of most of the concentrated diffraction spots.

[0065] As shown in FIG. 1b, a plurality of branch lines are attached to and extend from the main line. In FIG. 1b, branch lines 131-134 included in electrode 121 and branch lines 141-144 included in electrode 112 are shown. These branch lines are attached to the main line and extend into the area between the main lines. FIG. 1b shows one such area: area 150 between electrode 121 and electrode 112. Branch lines 131 and 132 of electrode 121 and branch lines 141 and 142 of electrode 112 extend into area 150 between electrode 121 and electrode 112. Similar to the main lines, the branch lines are also alternating. In particular, the branch lines extending into the same area from two different electrodes are alternating when viewed, for example, in a first direction. In this example, branch lines 142, 132, 141, and 131 alternately belong to electrodes 112 and 121. For this reason, in the embodiment, the main lines are alternating when viewed in a second direction, and the branch lines are alternating when viewed in a first direction. The branch lines are included in either the first electrode or the second electrode. Typically, the first and second electrodes including those main lines and branch lines are not directly electrically connected, and thus an electric field can be established between the first electrode and the second electrode that includes those main lines and branch lines therebetween.

[0066] For example, when a virtual line is drawn in an overlapping region parallel to two consecutive main lines, this virtual line can cross alternately with branch lines from the first main line and branch lines from the second main line, etc.

[0067] Extending branches from the main line has several advantages. These branches affect the diffraction of the substrate even in the case of a straight main line. On the other hand, the branches increase the risk of disturbing the homogeneity of the electric field. In particular, hot spots are created in places close to the tips of the branches, and weak spots can be created in other places. In an embodiment, at least one of two consecutive branches extending into the same area extends at least half across that area. As a result, the non-transmissive state may become more homogeneous, and the transition between states may be faster and / or more homogeneous.

[0068] When those branches are perpendicular to the main line, while the point where a branch on one main line occurs is directly opposite the occurrence point on the adjacent main line (when viewed in the second direction), the branches cannot overlap. In this case, the branch generated from one main line is on the same line as the branch from the opposing main line, such that, for example, extending the branch would overlap with the branch from the opposing main line. In such a case, there is a risk that hot spots are created in places close to the tips of the branches, and weak spots are created in other places. This can be avoided, for example, by an appropriate angle such that there is an appropriate overlap. For example, this angle may depend, for example, on the line width and the line spacing.

[0069] Avoiding hot spots caused by, for example, branches on the same line, such as perpendicular branches, can be avoided in an embodiment by interlocking the branches. For example, the points on the main line where the branches occur can be offset from each other or staggered. This angle can be chosen such that the branches do not cross the next branch. Staggering can be used to avoid the branches being on the same line. In an embodiment, the branches are perpendicular to their main lines and staggered with respect to the branches of the subsequent main line. In an embodiment, the branches may not be perpendicular and may or may not be staggered. In an embodiment, for example, the angle of the branches can be selected from a range of, for example, about 5 degrees to about 85 degrees. When the line spacing is very large, the angle can be close to perpendicular.

[0070] In Fig. 1b, a dashed line is shown in the middle between electrode 121 and electrode 112. The distance 151 between electrode 121 and the middle line is half of the distance between two successive main lines 153. This dashed line is virtual and is not actually visible in the embodiment. In Fig. 1b, branch lines 131 and 132 extend beyond the dashed line, that is, at least half of them extend across area 150. For example, branch line 131 or 132 can be projected in the second direction 102 on virtual line 162. The lengths of the projected branch lines 131 and 132 are longer than half of the distance between electrodes 121 and 112. The branch lines on the opposing main lines may or may not exceed half of the distance between the main lines; as shown in Fig. 1b, branch lines 141 and 142 do not exceed half, but branch lines 141 and 142 may be extended to pass through the middle line of the dashed line.

[0071] In the embodiment, these branch lines form angles with those electrodes that are significantly different from orthogonality, for example, at least 5 degrees different (out of 180 degrees), for example, at least 5% of a right angle, etc. By having different values, the diffraction effect is reduced.

[0072] In the embodiment, two successive branch lines extending into the same area between the first main line and the second main line overlap in the second direction when projected in the first direction. For example, Fig. 1b shows two successive branch lines: branch lines 141 and 131. The area where these two branch lines overlap is shown as a dashed ellipse in Fig. 1b. When these two successive branch lines are projected in the first direction on virtual line 162 extending in the second direction, branch lines 131 and 141 overlap at projection 161. Fig. 5a shows examples of both cases where the overlap is smaller and where the overlap is larger.

[0073] For example, simulations for embodiments having branch lines entering an area only with the following amounts: 60 - 50; 63 - 46; 64 - 45; 60 - 46, 65 - 61; 83 - 78; 95 - 95 were successfully carried out. Figure 1b shows branch lines having an entry of 80 - 40 and an overlap of 20 in terms of the percentage of line spacing. These numbers refer to the percentage of the line spacing into which the branch lines enter. The length of the branch lines is here measured, for example, only along the second direction after projection in the first direction. The length of the overlap in the second direction in some embodiments may be, for example: 10; 9; 9; 6; 26; 61; 95, etc. The latter is expressed as a percentage of the line spacing.

[0074] In an embodiment, the distance from the tip of a branch line, for example branch line 131, to a main line that continues, for example main line 112, is approximately equal to the distance between the branch line and a subsequent branch line, for example the distance between branch lines 131 and 141. For example, the larger of these two distances can be less than 110% of the smaller of these distances.

[0075] In an embodiment, when measuring the distance between two subsequent branch lines from the same main line extending within the same area between the first main line and the second main line in the first direction, it may be significantly smaller than the line spacing. For example, the said branch line distance may be no more than 5% of the line spacing. However, other embodiments have a large distance, for example 30% or more of the line spacing. For example, branch lines 131 and 132 extend into the same area between main lines 121 and 112.

[0076] Generally speaking, when branch lines are applied across a design, for example, the beneficial effects of applying the branch lines are enhanced. For example, it is not necessary for the branch lines to be applied to the entire part of the substrate, but by doing so, the favorable effects of the branch lines can be recognized throughout. However, for example, there may be various reasons not to use branch lines for parts where, for example, an optical difference is desired for visually discriminating that part, or for parts that use different methods to avoid diffraction, such as waves.

[0077] FIG. 1c schematically shows an example of an embodiment of a branch line on a substrate. FIG. 1c is drawn to a certain scale. In substrate 171, two consecutive branch lines do not overlap; an example with a -5% interval as shown is presented. In substrate 172, two consecutive branch lines do not overlap but reach the same point in the area between the two main lines; an example with a 0% interval as shown is presented. In substrate 173, an example of an embodiment with a 5% overlap of two consecutive branch lines is shown. In substrate 174, an example of an embodiment with a 20% overlap of two consecutive branch lines is shown. Substrate 174 shows that branch lines extending from both sides into the same area can extend more than half of the line interval. By overlapping the branch lines, the tendency of hot spots is reduced.

[0078] Two consecutive branch lines of different main lines may have the same length or different lengths. This offsets the area where the two branch lines overlap.

[0079] For example, in an embodiment, the longer branch line can be at least 5% longer than the shorter branch line. For example, the longer branch line can be up to 50% longer than the shorter branch line. For example, the length of the longer branch line measured along the branch line can be 1.05 times the length of the shorter branch line measured along the branch line. In an embodiment, the longer branch line can be between 4% and 40% longer than the shorter branch line.

[0080] For example, in an embodiment, two consecutive branch lines of different main lines have the same length.

[0081] In an embodiment, the electrode includes a plurality of straight main lines from which branch lines extend. The main lines, also called center lines, may be parallel to each other. The distance between two branch lines is called the branch line interval and is, for example, distance 152. The distance between two main lines is the line interval. The pitch may be 1 line interval + 1 line width, i.e., the width of 1 entity that can be repeated.

[0082] For example, the distance between points where branch lines occur on the main line may be referred to as the branch line interval. This branch line interval can be constant in the case of branch lines extending within the same area. The branch line interval may also vary along the main line. The branch lines may be alternating or staggered, for example, they may be offset by half of the branch line interval between them. The advantage of the branch lines is that they can make the distance between the electrodes uniform, and thus an electric field can be established between the electrodes. At the same time, the diffraction effect can be reduced, for example, by disturbing the repeatability of the design.

[0083] In an embodiment, the electrode line has a width selected from the range of about 1 to 50 micrometers. This line interval can be selected from the range of about 50 to 100,000 micrometers. For example, the line interval may be 800 micrometers, for example, within the range of 50 - 1000 micrometers, but even larger line intervals are possible. By having branch lines, a uniform electric field can be maintained while having a large line interval. By increasing the line interval, the diffraction effect associated with the main line is reduced. In an embodiment, the line interval is at least 500 micrometers.

[0084] In an embodiment, the length of the branch lines can vary. For example, the lengths of the branch lines may alternate along the main line, or may follow, for example, the lengths of a series of repeated branch lines. This has the advantage of staggering the points of maximum electric field. This is particularly beneficial in the case of large line intervals, for example, 500 micrometers or the like. For example, the lengths of successive branch lines may differ by about 60% in an embodiment.

[0085] In an embodiment, a plurality of main lines of the first and second electrodes are alternately arranged on a substrate with respect to each other. One way to achieve this is by forming the first and second electrodes in a comb shape, where the teeth of the comb are the main lines. By intermeshing the teeth of two combs, an intermeshing pattern is obtained. It is not necessary to use two comb shapes. For example, FIG. 1d is a diagram schematically showing an example of an embodiment of a first electrode and a second electrode arranged in a pattern across a substrate. For the sake of brevity, FIGS. 1a and 1d show only the main lines and not the branch lines. This pattern is created such that there is no direct electrical contact between the two electrodes. A minimum distance between the two electrodes may be implemented.

[0086] A design with branch lines contributes to reducing diffraction because it increases the number of angles on the substrate. Furthermore, many parameters can be changed to increase this effect. For example, the length of the branch lines, the angle of the branch lines, the distance between branch lines along the main line, the line pitch, etc. can be changed. Preferably, the branch lines within the same area are at least locally parallel, and thus the branch line angle on the right side of the main line is the same as the branch line angle on the left side of the next main line. When the line pitch is changed, the branch line distance may also change proportionally, for example, depending on the line pitch; for example, in order to implement the minimum intensity in the electric field, the maximum electrode distance between two consecutive branch lines can be maintained.

[0087] FIG. 2a is a diagram schematically showing an example of an embodiment of a substrate 200. Four of the main lines: main lines 201 - 204 are shown in FIG. 2a. For example, main lines 201 and 203 may be included in a first electrode, for example, electrode 110, and main lines 202 and 204 may be included in a second electrode, for example, electrode 120. A line pitch 251, for example, the distance between main lines 201 and 202, is shown. Also shown are the line pitch 252 between main lines 202 and 203 and the line pitch 254 between main lines 203 and 204. In this example, the line pitch varies in a second direction. For example, line pitch 251 is different from line pitch 252, and line pitch 252 is different from line pitch 253. Changing the line pitch contributes to reducing the diffraction effect.

[0088] Figure 2b is a diagram schematically showing an example of an embodiment of a substrate. Main lines 201 - 206 are shown. These main lines have different portions where the line intervals can vary differently. For example, a portion or region of the main line can extend in a second direction across the substrate. In Figure 2b, two portions: portion 221 and portion 223 are shown. As illustrated in Figure 2b, in portion 221, the line intervals are proportional to 11, 9, 7, 9, 11, while in portion 223, the line intervals are proportional to 7, 11, 9, 9, 11. The line interval between two consecutive main lines thus varies in the first direction as well as in the second direction in this example. Between the first portion 221 and the second portion 223, there is a connection portion 222 where the main lines of the two portions are connected. The line intervals in portion 221 are selected according to an alternating increase and decrease pattern of the line intervals. The line intervals in portion 223 are randomly selected.

[0089] For example, in an embodiment, the line intervals alternate between an increase to a maximum distance and a decrease to a minimum distance. For example, it may increase by a predetermined amount or a randomized amount until it reaches the maximum distance, and then the line interval may be decreased in the same way until it reaches, for example, the minimum line interval. Various strategies are given below to ensure that the line intervals vary overall.

[0090] For example, in an embodiment, until it reaches the maximum value, for example, compared to the initial value, for example, until an additional 20% maximum is reached, the line interval is increased by 3%. For example, if i x is the line interval and x0 is the initial line interval, then x i may have x = x i+1 * 1.03 until x i > 1.2 * x0. After that point, the line interval may decrease in the same pattern or by the same percentage or the value may be reset and the pattern starts again, etc.

[0091] For example, in an embodiment, the line spacing is alternately increased and decreased by a certain percentage of the previous value, for example, 7%. If the spacing is less than some value less than the initial value, for example, less than 10 micrometers, the spacing can be reset. For example, until reaching the point of x i <up to the point of x0 - 10 according to rule x i+1 =1.07*x i and rule x i+1 =0.93*x i can be alternated. After that point, the line spacing may be decreased in the same pattern or the same percentage. These values can be modified.

[0092] Another option is to alternate the increase and decrease, but the amount depends on the difference from the initial value. For example, x i+1 =α(x i -x0) can be set. Also in this case, the line spacing can be reset when exceeding the maximum or minimum value. Values of α greater than 1 or less than 1 can be alternated; for example, x i+1 =α i (x i -x0) can be used, with even indices i using α i >1 and odd indices using α i <1.

[0093] Another option is to alternate high and low values of the line spacing. For example, the high values may be randomly selected from a high range, and the low values may be selected from a low range. The high range and the low range may be separate or may partially overlap.

[0094] The line spacing may be changed randomly. For example, it may be completely random or random using additional criteria such as alternating large and small line spacings. For example, odd line spacings may be derived from a probability distribution different from that of even line spacings. In two distributions with different high and low expected values, for example, the higher expected value may be at least 10% or 20% higher than the lower expected value.

[0095] When the line spacing is randomly selected or modified, additional criteria can still be met. Above, it was stated to implement a maximum line spacing and a minimum line spacing. Another beneficial criterion that can be implemented is that the sum of the line spacings lies between a minimum total distance and a maximum total distance. This has the advantage that the connection portion 222 remains controlled. This can be obtained by deriving from a combined distribution conditioned on the desired criteria. This can also be obtained, for example, by first randomly selecting and then modifying that random selection until the constraints are met.

[0096] For example, in an embodiment, min x ≦ x i ≦ max x and min s ≦ Σx i ≦ max s where, if min x , max x , min s , max s are limits regarding the line spacing and the sum of the line spacings, the line spacing x i can be selected. These line spacings may vary randomly, for example, in a predetermined pattern as proposed above, or derived from one or more distributions.

[0097] The line spacing may be varied in a second direction along with the first direction. In this case, the variation can be controlled to control the shape of the connection portion. For example, FIG. 2c is a diagram schematically showing an example of an embodiment of a substrate. Two main lines 201 and 202 are shown. At the upper part of FIG. 2c, there is a line spacing 231. This line spacing varies at the lower part of FIG. 2c. The main line 201 is shown by a dashed line as to how it would continue if no shift occurred. The distance 232 is the distance between the main line 201 shown by the dashed line after the shift at the lower part of the figure and the main line 202. By maintaining a percentage increase or decrease of the distance 232 compared to the line spacing 231 below the threshold value, the connection portion is controlled, for example, to prevent it from becoming too abrupt. For example, in an embodiment, the distance 232 is less than 1.35 times the line spacing 231. This variation of the line spacing can be controlled similarly. Instead of (or in addition to) controlling the size of the line spacing, the angle formed by the connection portion in the main line, for example, the angle formed by the connection portion in lines 201 and 202, etc., is controllable. For example, in order to avoid the lines becoming too abrupt, the angle should be controlled to be less than a threshold value. Another way to control this is to verify that the subsequent connection portions do not approach each other too closely.

[0098] According to simulation experiments, it is confirmed that varying the line spacing is beneficial for reducing diffraction compared to a constant line spacing. It has also become clear that the randomness of the line spacing acts well in reducing the diffraction effect. Although the gradient pattern within the line spacing can reduce diffraction, a more randomized change in the line spacing does not act as well. For example, when the line spacing alternates between a randomly low value and a randomly high value, the diffraction is most reduced. The diffraction effect can be further suppressed by the branch lines.

[0099] Selecting an effective electrode pattern can be performed by a computer. For example, it is possible to automatically generate a number of electrode patterns and calculate diffraction parameters indicating the severity of the diffraction effect for those patterns. In some cases, other parameters can also be calculated, such as a homogeneity parameter indicating the homogeneity of the electric field. An effective pattern may be selected from the generated electrode patterns based on these computer parameters.

[0100] FIG. 3 is a diagram schematically showing an example of an embodiment of the substrate 300. In FIG. 3, a main line formed as a continuous connection of sub-main lines is shown, and branch lines extend from the sub-main lines. This sub-main line may correspond to the portion described with reference to FIG. 2b, but is not essential. For example, the portion as in FIG. 2b may include a plurality of sub-main lines.

[0101] In FIG. 3, a main line 301 including two sub-main lines 322 and 312 and a connection portion 311 is shown. The boxes 320 and 310 indicated by dashed lines indicate the sub-main lines together with some branch lines. Such boxes may be selected as units, for example, may be repeated as units, or may be selected from a plurality of units, such as randomly.

[0102] The advantage of the module design in FIG. 3 is that many parameters of the branch lines can be selected simultaneously. For example, the branch lines extending on the same side of the sub-main line may have equal lengths, and the branch lines extending on the same side of the sub-main line may be parallel. Further, the number of branch lines extending from both sides of the sub-main line may be equal. These selections facilitate more effective design choices because the number of parameters requiring control is reduced. For example, the sub-main line and its branch lines selected at a certain position may be repeated at other positions.

[0103] On the one hand, the design of FIG. 3 still allows for significant variations. For example, a branch line extending on the same side of a secondary main line and a branch line extending from a subsequent secondary main line of the same main line may have different lengths and may form an angle different from the first direction. Both options are shown in FIG. 3. Different secondary main lines may also have different numbers of branch lines extending from their sides; this is not shown in FIG. 3. The angle formed by a branch line and the first direction in the main line or secondary main line can be randomly selected between a minimum angle and a maximum angle, for example, between 45 degrees and 90 degrees. It should be noted here that the secondary main line 322 and the secondary main line 312 are shifted relative to each other in both the first direction and the second direction. Fixing some parameters within the dashed box significantly reduces the selection effort without greatly affecting the achievable results.

[0104] In an embodiment, the line width can be selected from the range of about 1 - 50 micrometers. This line spacing can be selected from the range of about 40 - 100000 micrometers. For example, the length of the secondary main line in FIG. 3 or the portion in FIG. 2b, for example, can be related to the line spacing. For example, their lengths measured in the first direction, for example, can be selected between 5 times and 10 times the line spacing. Generally, different values are possible, but these selections have been found to be efficient. FIGS. 2a - 2c do not show branch lines, but branch lines may be present as in the embodiment. The number of branch lines in the secondary main line or portion may similarly be changed, for example, from 3 to 10.

[0105] Changing the line spacing without the branch lines also reduces the diffraction effect, but it is better to combine these options. In fact, it is possible to create a substrate without using branch lines. An example of such a substrate is the substrate (100) used in smart glazing, where the first electrode (110) and the second electrode (120) are applied on the same side of the substrate, and each of the first and second electrodes is arranged in a pattern across the substrate. The first electrode and the second electrode each comprise a plurality of main lines (111 - 113, 121 - 123) extending in a first direction (101) across the substrate. The first and second plurality of main lines of the first and second electrodes are alternately arranged relative to each other on the substrate. The distance between the main lines (201, 202, 203) and the adjacent or subsequent main lines (202, 203, 204) of the first electrode (201, 203) and the second electrode (202, 204) on the substrate changes in a second direction and / or the first direction. Due to the change in line spacing, diffraction is reduced in this substrate. The substrate may be combined with the features described herein, particularly those related to the changing line spacing.

[0106] Most of the figures show main lines that are a combination of straight main lines or straight sub - main lines. However, this is not essential. For example, the main lines may be wavy, such as a sine - wave shape as shown in, for example, PCT / EP2020 / 052379. Figure 4a is a schematic view showing an example of a substrate with a plurality of main lines, where the main lines are wavy. The main lines are connected to two or more electrodes, as shown, for example, in Figure 1a or Figure 1d. The example of Figure 4a does not include branch lines, but branch lines can be incorporated in the same way with the wavy main lines. In this situation, managing the position, angle, and length of the branch lines is a major problem because the distance between the main lines is not fixed along the line. Further reduction of diffraction becomes possible by improving the ability to change the design. Figure 4b shows a schematic pattern of a substrate where the branch lines are combined with non - straight main lines, such as wavy main lines. The branch lines do not have to be straight either.

[0107] Using a wavy main line may increase homogeneity and hot spots may be reduced without overlapping branch lines. An example of such a substrate is the substrate (100) used in smart glazing, where a first electrode (110) and a second electrode (120) are applied on the same side of the substrate, and each of the first and second electrodes is arranged in a pattern across the substrate. The first electrode and the second electrode each comprise a plurality of main lines (111-113, 121-123) extending in a first direction (101) across the substrate. The plurality of main lines of the first and second electrodes are alternately arranged relative to each other on the substrate. A plurality of branch lines (131-134, 141-144) extend from the main lines into the area between the main lines. The branch lines (142, 132, 141, 131) extending into the area (150) between the first main line (121) and the second main line (112) of the first electrode and the second electrode extend alternately from the first and second main lines, and one or more or all of the main lines are wavy.

[0108] FIG. 4c is a diagram schematically showing an example of an embodiment of a substrate 450, in which the pattern in which the first and second electrodes are arranged is subdivided into a set of blocks extending across the substrate in the first and second directions. These blocks contain portions of the electrode pattern, and thus a larger pattern is constructed by combining these blocks. For example, each block may comprise a plurality of sub-lines of a portion of the plurality of main lines of the first electrode and a plurality of sub-lines of a portion of the plurality of main lines of the second electrode. The side of the block may be, for example, between 1 mm and 10 mm. For example, the block may be 8 mm×8 mm.

[0109] The blocks may be arranged in some regular pattern, such as a checkerboard pattern, but an irregular pattern, such as that shown in FIG. 4c, is also possible. The blocks may be rectangular. The advantage of using blocks is that beneficial blocks with, for example, a particularly low diffraction effect and / or a particularly good homogeneous electric field can be repeated a plurality of times on the substrate.

[0110] One or more of the blocks include the pattern according to the embodiment, but some blocks can equally well include other patterns such as a pattern without branch lines such as the pattern shown in FIG. 4a, for example. Some of the main lines in the block may be straight, and some may be wavy. Some may have branch lines and some may not, and so on.

[0111] Interestingly, when dealing with line shapes at the micro level, as shown in various examples herein, it may affect parameters such as diffraction and homogeneity, but it may also prevent the geometry of larger-scale designs and still have a significant optical impact. Therefore, it is possible to combine various electrode shapes made as blocks at different levels. From the perspective of the block structure, the blocks can be created at different levels, for example, various levels of randomization, while increasing the pattern size. In practice, it is convenient but not essential for the number of lines in the block to be a multiple of 2.

[0112] In an embodiment, the electrodes are driven by an electrical circuit that supports a limited number of voltage sources, for example, four voltage sources. In an embodiment, the number of voltage sources is equal to the number of electrodes that may be more than two on a given substrate. In an embodiment, the plurality of lines on the substrate are divided across more than two electrodes, or even more than four electrodes, or even more electrodes. It is preferable that the number of main lines per electrode is substantially equal. For example, in an embodiment, a plurality of segments are arranged on the substrate, and each segment is controlled by at least two electrodes with respect to the substrate and at least four electrodes in the assembly of at least two substrates. By driving the corresponding electrodes, different optical effects can be configured on different segments. Although possible, the fluid does not have to be restricted to one segment. If the segments are separated from each other, different fluids can be provided to them.

[0113] FIG. 5a is a diagram schematically showing a plurality of examples of embodiments of a substrate having an electrode pattern according to an embodiment. All the embodiments shown in FIG. 5a are at a certain scale and can be enlarged to the entire electrode pattern, for example, the following interlocking pattern.

[0114] FIG. 5b is a diagram schematically showing an example of an embodiment of a substrate configured for two or three electrodes. The left side of FIG. 5b shows that the main lines labeled with the letters "a" and "b" belong to the same electrode. All the lines marked with "a" are electrically connected, but this is not shown in detail in the electrode pattern shown in FIG. 5a or FIG. 5b; the same is true for the main line "b". The right side of FIG. 5b shows that the main lines labeled with the letters "a", "b", and "c" belong to the same electrode. All the lines marked with the same letter are electrically connected.

[0115] FIGS. 6a and 6b are diagrams schematically showing comparative examples of two substrates. FIGS. 6c - 6d are diagrams showing examples of two embodiments. The diffraction patterns were simulated. Simulating the diffraction pattern is essentially known in the art.

[0116] The diffraction level was calculated according to the method described in "Numerical comparison of grid pattern diffraction effects through measurement and modeling with OptiScan software", Murray et al., published on May 20, 2011, SPIE journal (doi:10.1117 / 12.883422). This method consists of calculating the power spectrum of an image representing the electrode pattern where the electrodes are drawn in black on a white background. From this raw power spectrum, the diffraction level is calculated as the ratio of the maximum intensity of the higher-order diffraction to the intensity of the zero-order diffraction.

[0117]

Table 1

[0118] Figure 6a shows, on the left side, a simple pattern consisting only of a plurality of straight main lines. These main lines are electrodes and are connected together, for example, by two electrodes of an interlocking pattern. The pattern of Figure 6b has additional straight lines that are orthogonal. It should be noted here that even if this pattern is rotated, only the diffraction pattern is rotated, which is not helpful. Figures 6c and 6d are diagrams schematically showing examples of embodiments of the substrate. Figure 6c uses varying line spacings, varying angles, and shifting secondary main lines. Figure 6d uses a higher density of block variations along the lines, that is, a larger number of vertical blocks. Figure 6c shows three blocks and the main line changes direction three times. Figure 6d has ten blocks and its main line changes direction ten times. It should be noted that the maximum diffraction values for the values 6c and 6d are significantly lower than those of linear designs such as Figures 6a and 6b.

[0119] The pattern of Figure 6b not only has unfavorable diffraction values but also tends to generate hot spots between opposing branch lines. In the region between the tips of the opposing branch lines, the electric field is much higher than elsewhere. As a result, there is a non-uniform appearance in the opaque state and a non-uniform transition speed.

[0120] The wavy line design of Figure 4a gives values similar to those of the design of Figure 6c, but it has been found that a design with branch lines is quicker and easier to make beneficial selections. Furthermore, a design with branch lines provides a more uniform electric field than the wavy line design.

[0121] Two substrates according to an embodiment can be joined to form an optical modulator. This optical modulator is particularly suitable for glazing. An exemplary embodiment of the optical modulator is shown below.

[0122] Figure 7a is a diagram schematically showing an embodiment of an optical modulator 10 that can be applied in smart glazing.

[0123] Reference is made to patent application PCT / EP2020 / 052379, which is incorporated herein by reference; this application includes a beneficial design for an optical modulator, which design can be further improved, for example, by including electrodes and / or branch lines as described herein.

[0124] The optical modulator 10 can be electronically switched between a transmissive state and a non-transmissive state, and vice versa, or between a reflective state and a non-reflective state, and vice versa. The optical modulator 10 comprises a first substrate 11 and a second substrate 12 which are arranged to face each other. Inside the first substrate 11, at least two electrodes are applied; electrodes 13a, 13b are shown. These at least two electrodes are collectively referred to as electrode 13. Inside the second substrate 12, at least two electrodes are applied; electrodes 14a, 14b are shown. These at least two electrodes are collectively referred to as electrode 14.

[0125] A fluid 15 is provided between the substrates. This fluid contains particles 30 which are, for example, nanoparticles and / or microparticles, and the particles are charged or chargeable. For example, the particles can inherently carry a charge on their surface. For example, the particles can be surrounded by charged molecules.

[0126] The electrodes are configured to drive the particles 30 and move them towards or away from the electrodes in response to the applied electric field. The optical properties, in particular the transmittance or reflectance of the optical modulator, depend on the location of the particles 30 in the fluid. For example, a connection can be provided to apply an electromagnetic field to the electrodes.

[0127] In one example, the substrates 11 and 12 may be light transmissive outside the electrodes, with a transmissivity of >95%, for example >99%, at typically relevant wavelengths. Taking the electrodes into account, the transmittance may be very low, for example 70%. The term "optical" may, where applicable, relate to wavelengths visible to the human eye (from approximately 380 nm to approximately 750 nm), and may include a wider range of wavelengths including infrared (from approximately 750 nm to 1 μm) and ultraviolet (from approximately 10 nm to 380 nm), and, where applicable, may relate to sub - selections thereof. In an exemplary embodiment of the optical modulator, the substrate material is selected from glass and polymers.

[0128] In other examples, one substrate, such as the lower substrate 12, may be reflective or partially reflective, and the upper substrate 11 is transmissive. The optical properties, in particular the reflectivity of the optical modulator, depend on the location of the particles 30 in the fluid. When the panel is in the open state (vertical drive), the particles are mostly arranged between the opposing electrodes of the two substrates so that the incident light can pass through the transmissive upper substrate and the optical layer with relatively little hindrance and be reflected or partially reflected on the lower substrate.

[0129] The distance between the first substrate and the second substrate is typically less than 30 μm, such as 15 μm. In an exemplary embodiment of the optical modulator, the distance between the first substrate and the second substrate is less than 500 μm, preferably less than 200 μm, preferably less than 100 μm, and even more preferably less than 50 μm, such as less than 30 μm.

[0130] In one example, the modulator may be provided with a flexible polymer, and the rest of the device may be provided with glass. The glass may be rigid glass or flexible glass. Optionally, a protective layer may be provided on the substrate. If more than one color is provided, more than one layer of the flexible polymer may be provided. The polymer may be polyethylene naphthalate (PEN), polyethylene terephthalate (PET) (optionally with a SiN layer), polyethylene (PE), etc. In a further example, the device may be provided with at least one flexible polymer. Thus, the modulator can be attached to any surface, such as using an adhesive.

[0131] The particles 30 can be configured to absorb light, thereby preventing a specific wavelength from passing through. The particles 30 may reflect light; for example, this reflection may be specular, diffusive, or intermediate. The particles may absorb some wavelengths and reflect others. The particles may also, or instead, emit light, for example, using phosphorescence, fluorescence, or the like. The fluid can also emit light, but its emissivity is modulated by changing the location of the particles.

[0132] In an exemplary embodiment of the optical modulator, the size of the nanoparticles is 20 - 1000 nm, preferably 20 - 300 nm, and more preferably less than 200 nm. In an exemplary embodiment of the optical modulator, the nanoparticles / microparticles may include a coating on the dye and preferably include a core. In an exemplary embodiment of the optical modulator, the coating of the particles is formed from a material selected from conductor materials and semiconductor materials.

[0133] In an exemplary embodiment of the optical modulator, the particles are configured to absorb light having a wavelength in the range of 10 nm - 1 mm, such as 400 - 800 nm, 700 nm - 1 μm, and 10 - 400 nm, and / or to absorb a portion of the light having a wavelength range within 10 nm - 1 mm (filter), and are configured in combinations thereof.

[0134] In an exemplary embodiment of the optical modulator, the particles are charged or chargeable. For example, the charge on the particles can be from 0.1e to 10e (5*10 -7 -0.1 C / m2) per particle.

[0135] In an exemplary embodiment of the optical modulator, the fluid is present in an amount of 1 - 1000 g / m2, preferably 2 - 75 g / m2, more preferably 30 - 40 g / m2, such as 20 - 50 g / m2. Using this layout has the great advantage that very few particles can be used with very little fluid.

[0136] In an exemplary embodiment of the optical modulator, the particles are present in an amount of 0.01 - 70 g / m2, preferably 0.1 - 3 g / m2, such as 0.02 - 10 g / m2.

[0137] In an exemplary embodiment of the optical modulator, the particles have a color selected from cyan, magenta, and yellow, black and white, and combinations thereof.

[0138] In an exemplary embodiment of the optical modulator, the fluid contains one or more of a surfactant, an emulsifier, a polar compound, and a compound capable of forming a hydrogen bond.

[0139] Fluid 15 may be a non-polar fluid having a relative permittivity of less than 15. In an exemplary embodiment of the optical modulator, the fluid has a relative permittivity εr of less than 100, preferably less than 5, such as less than 10. In an exemplary embodiment of the optical modulator, fluid 15 has a kinematic viscosity greater than 10 mPa·s.

[0140] Electrodes 13a, 13b and electrodes 14a, 14b are in fluid contact with the fluid. This fluid may be in direct or indirect contact with the electrodes. For example, the fluid may contact a second medium having the electrodes, such as through a porous layer. In an embodiment, the electrodes cover about 1 - 30% of the substrate surface. In an embodiment, the electrodes comprise a conductive material having a resistivity of less than 100 nΩm (at 273 K; for comparison, the ITO used typically has 105 nΩm), which has a conductivity > 1*10 at 20 °C7 (similar to S / m). In an embodiment of the optical modulator, the electrodes include copper, silver, gold, aluminum, graphene, titanium, indium, and combinations thereof, preferably including copper. The electrodes may have the form of fine wires embedded in a polymer-based substrate; for example, in the form of copper fine wires.

[0141] In a connection for applying an electromagnetic field to the electrodes, the applied electromagnetic field to this electrode causes the movement of nanoparticles and microparticles from the first electrode to the second electrode, and vice versa. A connection for applying an electromagnetic field to the electrodes may be provided. For example, in an exemplary embodiment of the optical modulator, the current is between -100 - +100 μA, preferably between -30 - +30 μA, more preferably between -25 - +25 μA. For example, the power provider may be electrically connected to at least two electrodes. This power provider may be configured to provide waveform power. At least one of the amplitude, frequency, and phase may be configurable to bring about different states in the optical modulator. For example, the aspect of the power may be configured by a controller.

[0142] The optical modulator 10 may include one or more segments, and the segments are a single optically switchable entity whose size may vary. The substrate at least partially encloses a volume that may be a segment.

[0143] The device may include a drive circuit for changing the appearance of the (individual) segments by applying an electromagnetic field. Accordingly, the appearance of the optical modulator or the appearance of one or more parts thereof may also be changed. For example, the segment may have an area of at least 1 mm 2 The design allows for stacking to enable more colors; for example, for full-color applications, a stack of two or three modulators may each provide most or all of the colors.

[0144] By having one or more segments, the optical modulator becomes locally controllable; this is beneficial depending on the application, but not essential. For smart glazing, the optical modulator can be used with or without segments. For example, when applied in smart glazing, the transmittance or reflectance can be locally controlled, e.g., to block a sun-patch without reducing the transmittance or reflectance across the entire window. The segments can be relatively large, e.g., having a diameter of at least 1 mm, or at least 1 cm, etc.

[0145] In an exemplary embodiment of the optical modulator, the substrates (11, 12) are aligned and / or the electrodes (13, 14) are aligned. For example, electrodes 13a, 13b and electrodes 14a, 14b can be aligned to face each other. In the aligned substrates, the electrodes on different substrates are behind each other when viewed in a direction orthogonal to the substrates. When the optical modulator is removed and both substrates are arranged such that the electrodes face upward, the electrode patterns are mirror images of each other.

[0146] Aligning the substrates can increase the maximum transmittance or reflectance of the optical modulator, while when selecting the optical modulator for criteria other than the range of transmittance or reflectance, etc., it may be better not to align the two substrates or not to align them completely. The optical modulators can be stacked. For example, two stacked optical modulators can be formed from three substrates, and the middle substrate has electrodes on both of its sides. In an embodiment of the optical modulator, optionally, at least one substrate 11, 12 of the first optical modulator is the same as the substrate 11, 12 of at least one second optical modulator. Also, in the case of stacked modulators, alignment can increase the maximum transmittance or reflectance, but may be detrimental for other considerations such as diffraction, etc.

[0147] FIG. 7b is a diagram schematically showing an example of an embodiment of the optical modulator 40. Except for including a plurality of optical layers as in the example showing a two-layer optical layer, the optical modulator 40 is the same as the optical modulator 10. There may be more than two optical layers. Each optical layer is disposed between two substrates. The optical modulator 40 can be regarded as a stack of optical modulators of two substrates as shown in FIG. 7a. As shown, the optical modulator 40 includes three substrates: a first substrate 41, a second substrate 42, and a third substrate 43. There is an optical layer between substrates 41 and 42, and there is an optical layer between substrates 42 and 43. These optical layers can be the same as the optical layers in the optical modulator 10. The controller 46 is configured to control the current on the electrodes of the substrates. For example, in FIG. 7b, the controller 46 can be electrically connected to at least 4×2 = 8 electrodes.

[0148] Interestingly, the particles in the plurality of optical layers may be different, and thus the plurality of layers can be used to control more optical properties of the optical modulator. For example, the particles in different optical layers can absorb or reflect at different wavelengths and can have different colors, for example. This can be used to create different colors and / or different intensities of colors on the panel of the controller 46. For example, a four-substrate panel can have a three-layer optical layer with different color particles, for example, particles of cyan, yellow, and magenta, respectively. By controlling the transmittance or reflectance of those different colors, a wide spectrum of colors can be created.

[0149] The surface of the substrate facing another substrate can have two or more patterns, for example, as in the embodiment. For example, the external substrates 41 and 43 can receive electrodes only on the inside, while the internal substrate, for example, substrate 42, can have electrodes on both sides.

[0150] Both substrates 41 and 42 can be regarded as an embodiment of the optical modulator. Similarly, both substrates 42 and 43 can be regarded as an embodiment of the optical modulator.

[0151] FIG. 7c is a diagram schematically showing an example of an embodiment of a vehicle 20 having smart glazing for a window 21. This is a particularly beneficial embodiment because during driving, the level of incident light can change frequently and rapidly. Using smart glazing in a vehicle has the advantage that the light level can be maintained at a constant level by adjusting the transmittance of the vehicle window. Furthermore, reducing the diffraction effect reduces driver distraction and thus improves safety. The vehicle 20 may include a controller configured to control the transmittance or reflectance of the window 21.

[0152] Smart glazing can also be used in other applications of glazing, such as buildings, offices, homes, greenhouses, skylights, etc., especially where the amount of incident light is variable. A skylight is a window placed in the ceiling so that sunlight can enter the room.

[0153] FIGS. 8a-8b schematically show side views of an embodiment when using a light modulator. When an electric field is applied to the electrodes on the substrate, an electric force is generated on the particles. Using this effect, the particles can move around, and thus different transmission or reflection states can be caused in the light modulator. The controller can control the electric field, for example, its amplitude, frequency, and phase. In an embodiment, the controller is connected to at least four electrodes: two electrodes for each substrate. However, more electrodes may be used and connected to the controller; for better fine-tuning of the gray scale and driving into a non-transmissive or non-reflective state, more than two electrodes, for example, may be used per substrate. A plurality of electrodes may also be used to support a plurality of segments on the substrate.

[0154] FIG. 8a is a diagram showing a light modulator to which no electric field is applied. In FIG. 8a, no electric force has yet been applied to the particles 30 floating in the fluid 15.

[0155] In the configuration shown in Fig. 8a, the conductive electrode pattern disposed on the upper substrate is completely aligned, or substantially aligned, with the conductive electrode pattern on the lower substrate. The conductive electrode pattern may be deposited on a transmissive or (partially) reflective glass substrate, or may be embedded in a plastic substrate or the like.

[0156] The alignment between the upper electrode pattern and the lower electrode pattern contributes to a wider range of achievable levels of transmissivity or reflectivity. However, alignment is not necessary since a similar effect can be obtained without alignment. Even without alignment, a similar range of transmittance or reflectance can be obtained.

[0157] It should be noted that in these examples, the upper substrate and the lower substrate are referred to as such to indicate the upper or lower substrate on the page. In glazing applications, the substrates may be aligned vertically rather than horizontally, and thus the same substrate may be referred to as, for example, the front substrate and the rear substrate.

[0158] Fig. 8b is a diagram showing an optical modulator. For example, in instance P1, a potential +V1 is applied to each fine wire electrode on the upper substrate, while a negative voltage, for example -V1, is applied to each fine wire electrode on the lower substrate. As a result, in this case, the same positive potential is applied to all electrodes 13, and the same negative potential is applied to electrodes 14. Due to this potential difference, negatively charged particles flow near the electrodes on the upper substrate, where the particles are substantially aligned with the upper electrodes. As a result, when both the upper substrate and the lower substrate are transmissive, the transmittance of the optical modulator 10 increases. Similarly, for example, when the upper substrate is transmissive and the lower substrate is reflective, the reflectivity of the optical modulator 10 increases. When the solution contains positively charged particles, the positively charged particles flow near the electrodes on the lower substrate, and those particles are substantially aligned with the lower electrodes.

[0159] In the second instance P2 in the ON state, in contrast to instance P1, when the voltages of the upper electrode and the lower electrode are reversed, a similar transmittance or reflectance can be achieved. In instance P2, the voltage of each electrode on the upper substrate supplies a negative potential -V1 there, and the voltage of the aligned electrodes on the lower substrate supplies a positive potential. This state is similar to the state shown in Fig. 8b, but the upper substrate and the lower substrate are reversed. Also in this configuration, the transmittance or reflectance of the optical modulator 10 is high.

[0160] Interestingly, by switching the positive potential of the electrode on the upper substrate (and the negative potential at electrode 14) as shown, for example, as electrode 13 in Fig. 8b, and the positive potential at the electrode on the lower substrate as shown, for example, as electrode 14 in Fig. 8b, the transmittance or reflectance can be maintained while reducing the corrosion damage to the electrodes. This alternating electric field can be achieved by applying an alternating potential to the upper and lower electrodes.

[0161] Applying a waveform is optional, but it is an effective means to increase the lifespan of the optical modulator by reducing corrosion. Corrosion can occur, for example, when using copper electrodes because copper ions dissolve in the ionic fluid on one substrate, flow to the electrodes of the opposing substrate, and deposit there. By applying a waveform, the direction of copper ion transport is frequently reversed, thus reducing the corrosion damage. Between the two instances P1 and P2, the corrosion current between the two substrates is balanced, or nearly, for example, >95% balanced. For example, when the corrosion rate of the electrodes on the upper plate occurs, there is a balanced deposition of copper at the lower electrode between each time instance P1, and the same is true for the reverse case in instance P2. Therefore, particles continuously migrate or transfer between the upper electrode and the lower electrode, and the optical modulator or the smart window is always in the ON state, while the dynamic electrolytic current between the upper electrode and the lower electrode becomes constant, and thus there is no net loss, or negligible net loss, of the electrode material on the upper and lower substrates.

[0162] Figure 8c is a diagram showing how a transmittance or reflectance reduction state can be obtained. An alternating voltage is applied on the same substrate. For example, in an embodiment, as shown in Figure 8c, a potential +V2 is applied to the first electrode, and the next adjacent electrode has the opposite potential -V2, and so on. This can be obtained by applying the potential +V2 to electrode 13a and the opposite potential -V2 to electrode 13b. On the opposing substrate, the potential +V2 may be applied to electrode 14a and the opposite potential -V2 may be applied to electrode 14b. For example, these electrodes may be arranged such that the electrodes on the substrate are aligned; the electrodes on the upper substrate have electrodes facing them on the lower substrate, and vice versa. For example, in order to reduce the transmittance or reflectance, the opposing electrodes may receive the same potential, while the adjacent electrodes receive opposite potentials. An embodiment in which four electrodes are denoted by reference numerals 13a, 13b, 14a, and 14b and the rest of the electrodes are continuously alternating is shown in Figure 8c.

[0163] By using this AC driving cycle between the upper substrate and the lower substrate, an electric field in the diagonal direction and an electric field in the horizontal direction are generated between the two substrates, thereby causing accidental diffusion of the particles, thereby creating a closed state of the optical modulator. As a result of this configuration, the particles migrate in the diagonal direction and the horizontal direction between the upper substrate and the lower substrate, and the diffusion of the particles into the visible aperture of the optical modulator contributes to the closed and opaque state of the optical modulator.

[0164] Regarding the transmission state shown in Figure 8b, for example, a waveform can be applied to the electrodes such that the electrodes shown in Figure 8b having a positive potential become negative, and vice versa. As in Figure 8b, for example, when a waveform is applied between electrode 13a and electrode 13b and between electrode 14a and electrode 14b, the corrosion damage to the electrodes is reduced.

[0165] The AC driving cycle can be implemented by using an interlocking line configuration that combines the configurations of the upper electrode and the lower electrode shown in the plan views such as Figure 5, Figure 6a - Figure 6d.

[0166] The degree to which the transmittance or reflectance increases or decreases in FIGS. 8b and 8c depends on the voltage and frequency differences. By changing the voltage difference, the amount by which the transmittance or reflectance increases and decreases, respectively, is controlled. For example, a curve representing light transmittance versus voltage may be determined, for example, measured. To obtain a specific level of light transmittance, for example, a specific transmittance, for example, a specific gray scale level, a corresponding voltage, for example, an AC voltage, may be applied. By interpolating signals in a transmitted state or a non-transmitted state, a level between transmission and non-transmission can be obtained. Similarly, a curve representing light reflectance versus voltage may be determined, for example, measured. To obtain a specific level of reflectance, a corresponding voltage, for example, an AC voltage, may be applied. By interpolating signals in a reflected state or a non-reflected state, a level between reflection and non-reflection can be obtained.

[0167] For the optical modulator, different electrode patterns can be used. Each electrode pattern can provide a range of gray scales that the optical modulator can obtain, for example, levels of transmissivity or reflectivity. However, the specific range of gray scales for any particular electrode pattern can be different from other electrode patterns. That is, different patterns give an increase in transmittance or reflectance or an increase in non-transparency, but the exact response to the drive signal depends on many factors including the specific pattern used. Changes in the optical properties of the optical modulator can have a fine resolution of less than, for example, 1 mm. It should be noted that pixelation of the optical modulator is not necessary to achieve different optical patterns, such as a visible logo in the optical modulator.

[0168] This effect can be used to embed a visible image in the optical modulator by locally changing the electrode pattern on the substrate of the optical modulator. For example, due to different electrode patterns, there may be a locally gray scale with a permanent offset of the gray scale relative to each other. For example, by locally changing the electrode pattern or its pitch, the maximum transmittance or reflectance can be changed.

[0169] As a result, the area on the optical modulator has different intensities of grayscale, for example different intensities of different grayscales, or different intensities of coloring. However, this area may have the same color point. In an embodiment, it can be switched together with the rest of the window at different ratios. For example, even when the same voltage is applied to the electrodes in two different areas, different electrode patterns cause different transmission states, for example different transmittance levels. For example, the curve representing transmittance versus voltage may be shifted. For example, when the voltage control is changed in the same way in both areas, the light transmittance may change in both areas, but by different amounts. The area can further reduce the response to the drive signal by reducing the density of the electrodes; in particular, the area can be formed so as not to switch at all, for example by not applying electrodes in the area.

[0170] This effect can be used to embed a logo in the optical modulator. For example, FIG. 9a is a diagram schematically showing an example of an embodiment of a logo and a grid. As shown in FIG. 9a, a first set of grid squares intersects the logo, and a second set of grid squares does not intersect the logo. For the first intersecting set, a different electrode pattern can be used than for the second set of grid squares. FIG. 9b is a diagram schematically showing an example of an embodiment of a substrate. In the area indicated by the first grid square, a different electrode pattern than the area indicated by the second grid square may be embedded in the first and second substrates, such as the substrate as in FIG. 7a. As shown in FIG. 9b, the two areas have different transmittances.

[0171] Figures 9c - 9d schematically show examples of embodiments of an optical modulator. In Figure 9c, the substrate is in a non - transmissive configuration, and in the area indicated by the logo, it is shown that the electrode pattern is configured to cause the optical modulator to be dark with low efficiency. In Figure 9d, it is shown that the same substrate is in a more transmissive configuration. It should be noted that although at different ratios, the transmittance increases in both the logo area and the area outside the logo. Even if the transmittance of those areas is close to each other here, the area indicated by the logo is still visible in Figure 9d.

[0172] Interestingly, this effect may only be achieved by different patterning, for example, by changing the pitch and / or design of the electrodes. Changing the waveform / current / voltage / power to this area is not necessary compared to other areas.

[0173] Especially in smart glazing, embedding an image in the optical modulator has many applications. For example, content such as logos, brands, etc. may be embedded. Textures may be embedded in the glazing. Contrast gradients may be embedded in the glazing. Other options include emergency signals such as arrows.

[0174] For example, in the windows of stores / restaurants: completely black windows may indicate that the store is closed, while a logo or any other designated design is visible when the store is open. This pattern may be a logo, etc., but this is not essential. The embedded image may also be a pattern that provides sufficient light inside while preventing passers - by from seeing inside the window. In particular, the embedded image does not necessarily need to contain a readable message. In car windows, when the vehicle is switched to the OFF state, for example, when parked, the glazing may become completely dark, while when the vehicle is switched to the ON state, a logo, for example, the manufacturer's logo appears.

[0175] By adjusting the design parameters, a certain local optical difference becomes visible compared to the background without a change in the electrical driving force. The parameters of the electrode pattern that affect the optical performance are: - Electrode line spacing - Electrode line thickness - Electrode line shape - Electrode line direction - Local variations in the cell gap, such as the distance between substrates - Distribution of the branch line length including.

[0176] For example, electrode line spacing, thickness, shape, and direction act on the local transmittance level and response time; the electrode line spacing / width locally affects the diffraction level that can also enable a specific local optical difference. Changes in the cell gap change the dark state level, and as a result, also change the maximum transmittance or reflectance and the response time. Another option is to vary the diffraction effect between two areas. For example, one area, such as most of the glazing, may have an electrode pattern with a low diffraction effect, while an embedded image may have an electrode pattern with a planned high diffraction effect.

[0177] Optical performance, including transmittance or reflectance, can also be changed by changing the electrode material; for example, by choosing an electrode material with different optical and / or conductive properties. The electrode material can affect light diffusion, reflection, and diffraction that can lead to additional optical effects. The conductivity of the electrode material when locally changed affects the potential at this location, and thus the electric field and, consequently, the transmittance level or reflectance level.

[0178] For example, the electrode material may be copper, aluminum, gold, indium tin oxide (ITO), etc. Cu / Al is reflective, while ITO is transmissive, so using different electrode materials can result in different appearances regardless of voltage driving. Similarly, different materials with different resistances produce different electric fields. For example, ITO has a smaller electric field even when driven at the same voltage.

[0179] Another way to obtain a change in transmittance or reflectance is by locally varying a spacer that can be applied between a first substrate and a second substrate. For example, different spacers can have different optical properties and densities. For example, spacers with different transmittances and different sizes may be used. The density of the spacers may also be different. In an embodiment, the density of the spacers may be increased by a factor of 1000 or decreased, giving a significantly different appearance. An increase of less than a factor of 1000 is also possible. The spacers can also be configured to intentionally vary the distance between the substrates and thus change their appearance.

[0180] Various options for locally changing the appearance of an area of a light modulator without changing the drive in that area may be applied to a light modulator having a single layer, such as a single fluid layer, such as a light modulator having two substrates; but may also be applied to a light modulator having multiple fluid layers and multiple layers of more than two substrates. The latter can be used to generate multiple colors.

[0181] The pattern in which the first and second electrodes are arranged is subdivided into a plurality of portions. For example, due to different electrode patterns, there may be two portions each having different optical properties; or there may be a plurality of portions. For example, this can be used to apply an image having not only black and white but also multiple levels of gray.

[0182] It is not necessary to use the substrate according to the embodiment to embed the logo. For example, a useful substrate that can be used in smart glazing includes a first electrode and a second electrode applied to the same side of the substrate. Each of the first and second electrodes is arranged in a pattern across the substrate, and each of the first and second electrodes includes a plurality of main lines extending in a first direction across the substrate, and the plurality of main lines of the first and second electrodes are alternately arranged with respect to each other on the substrate. The pattern in which the first and second electrodes are arranged is subdivided into a plurality of parts, and at least one of the electrode line spacing, electrode line thickness, electrode material, electrode line shape, and electrode line direction is different in the plurality of parts, resulting in different maximum transmittance or reflectance, or chroma.

[0183] Regardless of the presence or absence of branch lines, a substrate with such a logo embedded therein, or an optical modulator including such a substrate, can be combined with other features described herein.

[0184] FIG. 10 schematically shows an example of an embodiment of a method for controlling an optical modulator according to an embodiment. Method 500 can be implemented by a computer. Method 500 includes - selecting an alternating current of one of a plurality of maximum amplitudes corresponding to one of a plurality of levels of transmissivity in the optical modulator (510), - applying an alternating current to the electrodes to obtain an electromagnetic field between the electrodes that causes electrophoretic movement of particles towards or from the electrodes (520).

[0185] As will be apparent to those skilled in the art, many different ways of performing this method are possible. For example, the steps may be performed in the order shown, but the order of the steps can be changed and some steps may be performed in parallel. Further, other method steps may be inserted between the steps. The inserted steps may represent improvements to the method as described herein or may be unrelated to the method. For example, some steps may be performed at least partially in parallel. Further, a given step may not be completely finished before the next step is started.

[0186] Driving the electrode may use a signal having a selected maximum amplitude corresponding to one of a plurality of levels of transmissivity or reflectivity in the optical modulator. This signal may be an alternating current or an alternating voltage.

[0187] Embodiments of the method may be implemented using software that includes instructions for causing a processor system to perform method 500. The software may include only those steps performed by a particular sub - entity of the system. The software may be stored on a suitable storage medium such as a hard disk, floppy disk, memory, optical disk, etc. The software may be transmitted as a signal along a wiring, wirelessly, or using a data network such as the Internet. The software may be made available for download and / or for remote use on a server. Embodiments of the method may be implemented using programmable logic, such as a field - programmable gate array (FPGA), using a bitstream configured to perform the method.

[0188] The subject matter of the present disclosure is also understood to extend to a computer program, particularly a computer program carried on or in a carrier configured to put the subject matter of the present disclosure into practice. The program can be in source code, object code, intermediate source in code, and in any other appropriate form used in the implementation of the embodiments of the method, such as object code, or partially compiled form. Embodiments related to computer program products include computer-executable instructions corresponding to each of at least one of the processing steps of the methods described. These instructions may be subdivided into subroutines and / or stored in one or more files that can be statically or dynamically linked. Other embodiments related to computer program products include computer-executable instructions corresponding to each of at least one of the devices, units, and / or parts of the systems or products described.

[0189] FIG. 11a shows a computer-readable medium 1000 having a writable portion 1010 that includes a computer program 1020, which, according to an embodiment, includes instructions for causing a processor system to perform a light modulator method. For example, the processor system may be connected to a light modulator panel. The computer program 1020 may be embodied on the computer-readable medium 1000 as a physical mark or by magnetization of the computer-readable medium 1000. However, any other appropriate embodiments are equally conceivable. Further, although the computer-readable medium 1000 is shown here as an optical disk, it will be understood that the computer-readable medium 1000 may be any appropriate computer-readable medium, such as a hard disk, solid-state memory, flash memory, etc., and may be non-recordable or recordable. The computer program 1020 includes instructions for causing the processor system to perform the light modulator method.

[0190] FIG. 11b is a schematic representation of a processor system 1140 according to an embodiment of a controller for an optical modulator. This processor system comprises one or more integrated circuits 1110. The architecture of the one or more integrated circuits 1110 is schematically shown in FIG. 11b. The circuit 1110 comprises a processing unit 1120, such as a CPU, for executing a method according to an embodiment and / or running a computer program component for implementing its modules or units. The circuit 1110 comprises a memory 1122 for storing programming code, data, etc. A portion of the memory 1122 may be read-only. The circuit 1110 may include a communication element 1126, such as an antenna, a connector, or both. The circuit 1110 may comprise an application specific integrated circuit 1124 for performing some or all of the processing defined in the present method. The processor 1120, the memory 1122, the application specific IC 1124, and the communication element 1126 may be interconnected with each other via an interconnect 1130, such as a bus. The processor system 1110 may be configured for contact and / or non-contact communication using an antenna and / or a connector, respectively.

[0191] For example, in an embodiment, the processor system 1140, such as the present device, may comprise a processor circuit and a memory circuit, and the processor is configured to execute software stored in the memory circuit. For example, the processor circuit may be an Intel Core i7 processor, an ARM Cortex-R8, etc. In an embodiment, the processor circuit may be an ARM Cortex M0. The memory circuit may be a ROM circuit or a non-volatile memory such as a flash memory, for example. The memory circuit may be a volatile memory such as an SRAM memory, for example. In the latter case, the device may comprise a non-volatile software interface such as a hard drive, a network interface, etc., configured to provide software, for example.

[0192] For example, a controller for an optical modulator that controls the voltage applied to an electrode may include a processor circuit, or alternatively, may also include a state machine.

[0193] Figures 12 - 37 are diagrams schematically showing examples of embodiments of an optical modulator. In these figures, the voltages that can be applied to the electrodes are shown using voltage references V1, V2, … to indicate that the voltage can be applied to the electrode. The voltages indicated by different voltage references are typically different, but they may be equal. The driving of the electrodes may use a signal having a selected maximum amplitude. Using different voltages for one electrode, or several electrodes, or all electrodes results in a visual difference in the panel, and in particular, results in different optical characteristics depending on specific, for example, different transmittances. For example, the signal amplitude can be selected from a plurality of maximum amplitudes to achieve one of a plurality of transmittances. These signals may be alternating current or alternating voltage.

[0194] A positive or negative sign indicates whether the voltage is positive or negative with respect to the zero voltage reference. Other examples of the same embodiment can be obtained by replacing all positive signs with negative signs, and vice versa.

[0195] As an example, the various voltage references may be equal (except for the sign) to account for manufacturing variations, such as slightly different electrodes, non - flat substrates, etc. As an example, the various voltage references may be different to create intermediate transmittances, such as various grays, or various colors, or color intensities. As an example, intermediate voltages can be used to facilitate the dispersion or collection of particles. The use of different voltage references is beneficial, but useful examples of optical modulators can still be obtained by selecting all or some of the voltage references to be equal (except for the sign).

[0196] Typically, the electrodes are driven DC-neutral, for example, by applying an AC signal to those electrodes. In that regard, the voltage reference can be considered as the maximum amplitude of the AC signal, while the positive and negative signs indicate the phase of the signal.

[0197] The voltage sign (positive / negative indication) thus only applies for a specific period; the voltage sign for each electrode can be inverted for the next period. The figures are not to exact scale; for example, the electrodes on the substrate are not necessarily equidistant. The arrows in the figures indicate the main electric field lines.

[0198] The figures show a modulator with a first substrate and a second substrate, with an optical layer therebetween. A plurality of electrodes are applied inside them, each of which has a plurality of main lines. In the figures, the first and second substrates are also referred to as upper and lower for clarity. Although not stated, the substrates may be in any position, and the upper and lower may be, for example, the front and the rear. Expansion functions may be applied, but the electrodes in these figures do not show expansion functions such as branch lines.

[0199] The controller can be connected to the shown modulator to control the voltage created on the electrodes, as indicated, for example, by the voltage reference.

[0200] Note that many of the improvements described herein, such as having a branch line, having more than two electrodes on a substrate, etc., are particularly beneficial when combined; for example, the branch line reduces diffraction, and it should be noted that this effect is increased when multiple electrodes reduce the curtain effect. However, these extended functions as described herein below or elsewhere are also, for example, indecently beneficial without a controller configured to obtain one of a plurality of levels of transmissivity or reflectivity in an optical modulator by using one of a plurality of maximum amplitudes of alternating current. The following embodiments can be configured for a controller that cannot be driven using alternating currents of different maximum amplitudes by selecting voltages shown to be equal by a voltage reference.

[0201] FIGS. 12-15 schematically show examples of embodiments of an optical modulator having two electrodes applied to each substrate.

[0202] Having at least four independent electrodes, for example, when wiring at least two electrodes on each substrate in a device, it is possible to modulate the direction of the electric field as shown in the figure. As described above, the potential level can be modulated for each electrode. By using a single potential reference, a simplified optical modulator can be obtained.

[0203] FIG. 12 shows an example of driving an optical modulator to increase the transmittance.

[0204] FIG. 13 shows an example of driving an optical modulator to decrease the transmittance. It should be noted that the diagonal lines of force are created to increase the dispersion velocity of the particles. Further, the particles disperse more towards the middle of the optical modulator, which reduces the curtain effect.

[0205] Figures 13 and 14 are diagrams showing two different ways of driving towards a darker state. Figure 14 is a diagram showing an example of driving a light modulator where both the vertical electric field and the horizontal electric field are increased. Which of the vertical electric field and the horizontal electric field is more powerful for driving the dye depends on the design, for example, the dimensions of the cell pitch and the line pitch. When the distance between the electrodes is reduced and the particles move towards the electric field region where the electric field becomes the strongest, the electric field becomes stronger. If the difference in the electric field between the vertical electric field and the horizontal electric field in this case is not powerful enough, the light modulator demonstrates an intermediate open state when the design is homogeneous across the substrate.

[0206] If the design changes the light modulator and the distance between the electrodes within the same substrate and the distance between the substrates are not constant across the light modulator, locally, the highest electric field region along which the charged particles aggregate changes, and as a result, an optical difference is obtained. In some areas, the transmittance of the light modulator can be increased, while in other areas, the transmittance of the light modulator can be lower even with uniform electrical driving. This effect is less achievable with other driving methods, such as the method shown in Figure 13. This effect can be used, for example, to embed a logo in the light modulator.

[0207] Figure 15 is a diagram schematically showing an example of using an alternating current with one of the maximum amplitudes among a plurality of maximum amplitudes. The first electrode on the upper substrate is driven using a reference voltage +V, while the second electrode on the upper substrate is driven using a reference voltage +V / 2. The opposing electrodes on the lower electrode are driven using -V / 2 and -V respectively. It should be noted that the voltage difference between the opposing electrodes is + / - 1.5V, while the voltage difference between adjacent electrodes is + / - 0.5V. As a result, most of the particles react to the vertical electric field and settle to increase the transmittance, but the effect becomes smaller.

[0208] FIG. 16 and FIG. 17 schematically show an example of an embodiment in which one substrate has two electrodes and the other has three electrodes. In the embodiment, at least three electrodes are applied to at least one of the first substrate and the second substrate, and at least two electrodes are applied to the other substrate.

[0209] When additional electrodes are available, additional combinations of voltages can be obtained. This provides more control, for example, for grayscale. For example, in the case of five electrodes instead of four, addressing modes that are not achievable in a four-electrode system become possible.

[0210] Having at least three electrodes on a substrate can reduce the curtain effect; for example, instead of a uniform stepwise increase or decrease in transmittance, the curtain effect, which is a visual appearance of closing a curtain between the electrodes, can be reduced. For example, one or more, or all, of the additional electrodes on one of the substrates can be used to close (reduce transmittance) even if they are not used to open (increase transmittance). This curtain effect is essentially visually distracting and also increases diffraction.

[0211] The advantage of having at least three electrodes on a substrate is that it is possible to bring those electrodes closer together without reducing the maximum transmittance or reflectance. For example, in an embodiment, the electrodes on the substrate having at least three electrodes can be spaced 35 microns apart, while the electrodes on a facing substrate having, for example, two electrodes can be spaced 70 microns apart. These are exemplary numbers; the actual numbers can be changed depending on the requirements of the application.

[0212] Electrodes spaced closer together result in a stronger electric field, and thus faster closing, and therefore a reduced curtain effect. On the other hand, when open, if the additional electrodes are configured not to attract particles, the loss of maximum transmittance or reflectance is minimal.

[0213] In an embodiment, the additional electrode can be formed from a material different from other electrodes, such as a transparent material. For example, four electrodes may be formed of copper, while an additional fifth electrode is formed of ITO.

[0214] FIGS. 16 and 17 show an example where the distance between successive main lines of a plurality of electrodes on a first substrate is greater than the distance between successive main lines of a plurality of electrodes on a second substrate. For example, this distance may be twice the distance shown. For example, this distance may be at least twice, 1.5 times, or 1.2 times, etc.

[0215] FIGS. 16 and 17 show an example that promotes reducing the transmittance.

[0216] FIGS. 18 - 19 are diagrams schematically showing an example of an embodiment of an optical modulator having three electrodes on each substrate.

[0217] Having at least three electrodes on each side increases the advantages of having five electrodes. Since not all electrodes are necessary to open the device, it is possible to bring the electrodes closer on both sides without reducing the transmittance. Further, having three electrodes on each substrate allows six electrodes to be symmetrically arranged.

[0218] FIGS. 20 - 23 schematically show an example of an embodiment of an optical modulator having four electrodes on one substrate and two electrodes on the other substrate. As the number of electrodes increases, further modulation of the transmittance becomes possible and is controlled not only by particle movement but also by design. As shown in FIG. 20, the optical modulation area can be set to spread particles in the visible area, while other parts can be set to concentrate particles in a vertical electric field. This enables grayscale by design control. FIGS. 21, 22, and 23 show other examples of the relationship of potentials across two electrodes and four electrodes for modulating the grayscale.

[0219] Figs. 24 - 29 schematically show examples of embodiments of an optical modulator having four electrodes on each substrate. With these examples, even further control for grayscale becomes possible.

[0220] Fig. 30 is a diagram schematically showing an example of an embodiment of an optical modulator. The optical modulator of Fig. 30 has two electrodes on each side, but can be implemented using more than two electrodes.

[0221] The optical modulator shown in Fig. 30 has additional secondary electrodes running parallel to the primary electrodes. For example, the primary electrodes may be main lines or branch lines, etc. In Fig. 30, one primary electrode is indicated by reference numeral 3001, and one secondary electrode is indicated by reference numeral 3002. As shown in the figure, the secondary electrodes run along each of the primary electrodes, but this is not essential.

[0222] In the embodiment, the secondary electrodes are connected to the primary electrodes through the semiconductor layer, and the secondary electrodes are electrically connected to the primary electrode lines by the semiconductor layer, whereby only a transmission current exceeding the threshold voltage on the primary electrodes becomes possible. Therefore, the voltage switch can be handled by the potential.

[0223] Accordingly, the primary electrodes or portions thereof can be locally interconnected to the secondary electrodes. By interfacing with the semiconductor material layer, when the minimum potential is applied on the electrodes, the transmissive electrodes see only the potential. Thereby, a voltage switch handled by the potential can be created on the surface. The secondary electrodes may be transmissive. The second electrode may be the same size or a similar size as the primary electrode, or much larger.

[0224] In the embodiment, the secondary electrodes comprise capacitors configured to locally hold charges. This can be used for gain in power. A semiconductor layer is not necessary to form electrodes extended as capacitors.

[0225] In an embodiment, the secondary electrode includes a photoactive semiconductor material, and the secondary electrode provides power to the primary electrode line.

[0226] Figs. 31-33 schematically show an example of an embodiment of a substrate having two electrodes that extend two-dimensionally but are offset in a third dimension. These figures show top views. The two electrodes are each disposed in a plane, but their planes are offset with respect to each other. For example, the electrodes may be etched.

[0227] The interlocking pattern of the electrodes on each substrate enables the optical modulator to be set in a particle-dispersed state (typically, a dark state). An electric field parallel to the substrate provides a high level of homogeneity. The distribution of the electric field along the vertical axis, i.e., the axis from substrate to substrate, can be considered less homogeneous as it promotes the concentration of particles by the lines of force, and the physical inhomogeneity can be utilized to more easily create a gray scale.

[0228] The offset between the electrodes on the same substrate enables the angle between the interlocked main lines to reduce the diffraction level. Supplementary lines can be created to further reduce the diffraction problem and / or to reduce parallax. In an embodiment, a passive matrix design is used.

[0229] Offsetting the two electrode patterns at an angle may be applied within opposing substrate-to-substrate, or may be applied between patterns on different substrates. For example, the electrode patterns on different substrates may be offset at an angle. For example, in an embodiment, two or more interlocking electrodes may be applied to two parallel substrates, in which case the main lines in the two substrates are not parallel but form an angle with respect to each other.

[0230] Fig. 34 is a diagram schematically showing an example of an embodiment of an optical modulator, in which the electrodes on the first substrate are arranged in at least partially the same pattern as the second electrodes on the second substrate, and the patterns of the first and second electrodes are shifted with respect to each other.

[0231] In this example, misalignment based on a six - electrode system is shown. The misalignment reduces the parallax effect due to manufacturing alignment tolerances. One particular way of driving the system is shown in the figure.

[0232] Certain misalignments can be applied either globally or only locally to the device. For example, a certain misalignment can be made to act on the edges in order to prevent unwanted particle movement towards the edges, also known as the dye migration effect. In an embodiment, the alignment at a particular location can be corrected in order to better accommodate future bending of the optical modulator. By combining non - aligned patterns with aligned patterns between substrates, optical effects such as diffraction and / or parallax can be improved.

[0233] For example, in an embodiment, two or more interlocking electrodes may be applied to two parallel substrates, in which case the main lines on the two substrates are parallel but shifted relative to each other.

[0234] FIG. 35 is a diagram schematically showing an example of an embodiment of an optical modulator having four electrodes on each substrate. In an embodiment, different materials can be combined for the electrodes in order to reduce parallax.

[0235] For example, on each substrate, one of the two electrodes can be formed of a metal or a transparent material (e.g., ITO), or can have a different optical index. The electrodes on the opposing substrates are formed from other types of materials; for example, a transparent material can be a non - transparent material vice versa.

[0236] For example, in the eight - electrode system shown in FIG. 35, the electrodes surrounded by circles may be formed of a transparent material (e.g., ITO), and the other electrodes may be formed of a metal (e.g., copper) and be non - transparent. This reduces the impact of alignment tolerances regarding parallax even when the horizontal electrode shape design requires perfect alignment between the lower and upper substrates. Manufacturing variations also have less of an impact.

[0237] Figures 36 - 37 are diagrams schematically showing examples of embodiments of optical modulators having different geometries across substrates. For example, the electrode geometry may vary across at least one of the first and second substrates. For example, one or more of the thickness, width, shape, area, and volume of the electrodes may be different.

[0238] Using different electrode geometries can be combined with any type of electrode structure.

[0239] In an embodiment, the electrodes do not have the same height. Modifying the height of the electrodes affects both the electric field distribution and the liquid flow. Similarly, the shape of the electrodes parallel to the substrate may be from any form. The shape of the electrodes in the vertical plane compared to the substrate can also be shaped differently and can be, for example, a rounded rectangle or a non-rounded rectangle, a triangle, a trapezoid, etc.

[0240] Figure 36 shows an example of electrodes on substrates having different heights. Figure 36 also shows an example of opposing electrodes on different substrates having different heights.

[0241] Figure 37 shows an example of electrodes on substrates having different shapes. Figure 37 also shows an example of opposing electrodes on different substrates having different shapes.

[0242] An advantage of a greater height in the electrodes is that they are less affected by corrosion.

[0243] Figures 38 - 39 are diagrams schematically showing examples of physical contaminants that cause short - circuits between electrodes in prior - art optical modulators.

[0244] Figure 38 is a diagram schematically showing an example of physical contaminants that cause a short - circuit between electrodes on opposing substrates in a prior - art optical modulator.

[0245] Figure 39 is a diagram schematically showing an example of physical contaminants that cause a short - circuit between adjacent electrodes on a single substrate in a prior - art optical modulator.

[0246] Figures 40 - 44 are diagrams schematically showing examples of embodiments of an optical modulator.

[0247] Figures 40 - 45 are diagrams schematically showing examples of embodiments of an optical modulator, schematically showing various configurations of a protective coating, and further showing how these can prevent the formation of a short circuit between electrodes due to physical contaminants (not part of the embodiment).

[0248] Figure 40 shows an example of an electrode on a substrate provided with a protective coating that covers the entire substrate such that both the electrode and the substrate portion not covered by the electrode are covered by the protective coating. Figure 40 further shows an example of a counter electrode on a different substrate not provided with a protective coating.

[0249] Figure 41 shows examples of electrodes on both substrates provided with a protective coating that covers the entire substrate such that both the electrode and the substrate portion not covered by the electrode (and in fluid contact with the fluid) are covered by the protective coating.

[0250] Figure 42 shows an example of an electrode provided with a protective coating in a regular pattern or a random pattern, and not necessarily all electrodes are covered. In this example, a part of the electrodes on both the first substrate and the second substrate is covered by the protective coating.

[0251] Figure 43 shows an example of an electrode provided with a protective coating in a regular pattern or a random pattern, and not necessarily all electrodes are covered by the protective coating. In this example, a protective coating is provided such that both some but not all of the electrodes and some but not all of the inner surface of the substrate where no electrode is provided are covered by the protective coating. In this example, the protective coating is provided on a part of the electrodes on both substrates and on a part of the inner side of both substrates.

[0252] FIG. 44 shows an example of an electrode provided with a protective coating having a regular pattern or a random pattern, and not all electrodes are necessarily covered with the protective coating. In this example, the protective coating is provided such that both some, but not all, of the electrodes and some, but not all, of the inner surface of the substrate where no electrode is provided are covered with the protective coating. In this example, the protective coating is provided on only a part of the electrodes of only one substrate and on only a part of the inside of the only one substrate, but no protective coating is provided on the opposing substrate.

[0253] FIG. 45 shows an example of an electrode provided with a protective coating having a regular pattern or a random pattern, and not all electrodes are necessarily covered with the protective coating. In this example, the protective coating is provided such that both some, but not all, of the electrodes and some, but not all, of the inner surface of the substrate where no electrode is provided are covered with the protective coating. In this example, the protective coating is provided on a part of the electrodes of both substrates and on a part of the inside of both substrates. FIG. 45 also shows that some portions of the protective coating may have different thicknesses compared to other portions of the coating.

[0254] FIGS. 46-48 are diagrams schematically showing examples of embodiments of a substrate for use in an optical modulator having different geometries of a protective coating over the electrodes and the remaining portions of the substrate. For example, the geometry of the protective coating, such as one or more of shape (line, mesh, grid), coating width, coating length, coating thickness, presence or absence of a protective coating on the opposing substrate, and alignment of the coating on the opposing substrate, may vary over at least one of the first substrate and the second substrate.

[0255] FIG. 46 shows an example of a top view of a single substrate (depicted by dots) to which electrodes (gray lines) are applied, and a protective coating (black lines) is applied to the surface of the electrodes and the substrate where no electrodes are provided. In this example, the protective coating is applied in a pattern of parallel strips that form an angle with the main lines of the electrodes.

[0256] FIG. 47 shows an example of a top view of a single substrate (depicted by dots) to which electrodes (gray lines) are applied, and a protective coating (black lines) is applied to the surface of the electrodes and the substrate where no electrodes are provided. In this example, the protective coating is applied in a mesh-shaped pattern, and the main lines of the mesh-shaped pattern are shifted with respect to the main lines of the electrodes.

[0257] FIG. 48 shows an example of a top view of a lower substrate (depicted by dots) to which electrodes (gray lines) are applied, and a protective coating (black lines) is applied to the surface of the electrodes and the substrate where no electrodes are provided. Also shown in this example is a protective coating (black lines) provided on the surface of the electrodes applied on an upper substrate (not shown) and the surface of the substrate of this upper substrate where no electrodes are provided. In this example, the protective coating in the shape of parallel lines applied to both the upper substrate and the lower substrate forms a mesh-shaped pattern whose main lines are inclined with respect to the main lines of the electrodes.

[0258] Note that the above-described embodiments are illustrative rather than limiting the subject matter of the present disclosure, and it should be noted that those skilled in the art can design many alternative embodiments.

[0259] In the claims, reference signs enclosed in parentheses shall not be construed as limiting the claims. The use of the verbs “comprise,” “include” and conjugations thereof does not exclude the presence of elements or steps other than those recited in the claims. The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. Expressions such as “at least one of” when occurring after a list of elements represent a selection of any one or any subset of all of the elements from that list. For example, the expression “at least one of A, B, and C” shall be understood to include only A, only B, only C, both A and B, both A and C, both B and C, or all of A, B, and C. The subject matter of the present disclosure may be implemented by means of hardware involving several distinct elements, and by means of a computer suitably programmed. In device claims enumerating several parts, several of those parts may be embodied by one and the same item of hardware. The fact that certain means are recited in mutually different dependent claims does not indicate that a combination of these means cannot be used advantageously.

[0260] In the claims, references within parentheses refer to reference signs in the drawings of the exemplary embodiments or to formulae of the embodiments and are thus intended to make the claims more readily understandable. These references shall not be construed as limiting the claims.

Claims

1. 1. An optical modulator comprising: a first substrate and a second substrate, the first substrate and the second substrate being arranged with their inner sides facing each other; a plurality of electrodes applied to the inside of each of the first and second substrates, each of the first and second substrates having an inner surface area; each of the plurality of electrodes is arranged in a pattern across the substrate, each of the plurality of electrodes comprising a plurality of main lines extending in a first direction across the substrate, the main lines of the plurality of electrodes being alternatingly arranged with respect to one another on the substrate; and a plurality of electrodes, at least a part of the inner surface area of ​​at least one of the first and second substrates being provided with a protective coating; an optical layer between a first substrate and a second substrate, the optical layer comprising a fluid containing particles, the particles being charged or chargeable; a controller configured to apply a potential to the plurality of electrodes to obtain an electromagnetic field between the plurality of electrodes, causing a modulation of an optical property of the optical modulator, the electromagnetic field resulting in electrophoretic movement of the particles towards or away from one of the plurality of electrodes; An optical modulator comprising:

2. 10. The optical modulator of claim 1, wherein a protective coating is provided on at least a portion of an inner surface area of ​​one of the first and second substrates, and the inner surface of the opposing substrate is free of a protective coating.

3. 3. The optical modulator of claim 1, wherein a protective coating is provided on at least a portion of the inner surface area of ​​both the first and second substrates.

4. The optical modulator of claim 1 , wherein the protective coating covers at least 1% of the total inner surface area of ​​at least one of the first and second substrates.

5. The light modulator of claim 1 , wherein the protective coating covers at least 1% of the total inner surface area of ​​both the first and second substrates.

6. 6. An optical modulator as claimed in any one of claims 1 to 5, wherein the inner side of one of the first and second substrates is entirely provided with a protective coating, and the opposing substrate is not provided with a protective coating, such that substantially the entire surface of the plurality of electrodes applied to the inner side and substantially the inner side of the substrate not provided with electrodes is covered with the protective coating.

7. 7. An optical modulator as claimed in any one of claims 1 to 6, wherein the insides of both the first substrate and the second substrate are entirely provided with a protective coating such that substantially the entire surface of the plurality of electrodes applied to the inside and the inside of the substrate not provided with electrodes is covered with the protective coating.

8. 8. An optical modulator according to any one of claims 1 to 7, wherein the protective coating is provided as a patterned coating.

9. 9. The optical modulator of claim 8, wherein a first main line on a first substrate is provided with a protective coating and a second main line on a second substrate opposite the first main line is not provided with a protective coating, the second main line being in fluid contact with the fluid, or vice versa.

10. 10. The optical modulator of claim 9, wherein the plurality of main lines on the first substrate and the second substrate are alternately provided and not provided with a protective coating.

11. 11. An optical modulator as claimed in any one of claims 8 to 10, wherein a patterned coating is provided on at least a portion of the electrodes and optionally on the inside of one of the first and second substrates, but not on the opposing substrate.

12. 12. An optical modulator as claimed in any one of claims 8 to 11, wherein a coating is provided on the inside of at least one of the first and second substrates in a random pattern such that at least a portion of the multiple electrodes applied on the inside and / or the inside of the substrate not provided with an electrode is provided with a coating, and at least a portion of the multiple electrodes applied on the inside and the inside of the substrate not provided with an electrode is free of a coating.

13. 13. The light modulator of claim 1, wherein the protective coating is a transparent or semi-transparent coating.

14. 14. The light modulator of claim 1, wherein the protective coating is a reflective coating.

15. 15. The optical modulator of claim 1, wherein a protective coating provides additional optical functionality to the modulator.

16. 16. An optical modulator according to any one of the preceding claims, wherein the protective coating has a thickness in the range of 1 nm to 100 μm, preferably in the range of 10 nm to 50 μm, preferably in the range of 100 nm to 10 μm.

17. at least three electrodes are applied to at least one of the first and second substrates, or An optical modulator according to any one of claims 1 to 16, in which at least three electrodes are applied to both the first and the second substrate.

18. 18. An optical modulator according to claim 1, wherein the distance between successive main lines of the plurality of electrodes in the first substrate is greater than the distance between successive main lines of the plurality of electrodes in the second substrate.

19. 1. A light modulator having a transmissive state and a non-transmissive state, or a reflective state and a non-reflective state, - switching to a non-transmissive or non-reflective state by creating an AC voltage on at least one of the first and second substrates and applying an AC voltage between at least the first and second electrodes on the first substrate and / or the first and second electrodes on the second substrate, creating an AC voltage between the first and second substrates and switching to a transmissive or reflective state by applying an AC voltage between a first electrode on the first substrate and a first electrode on the second substrate and / or between a second electrode on the first substrate and a second electrode on the second substrate; 19. An optical modulator according to claim 1 , configured as follows:

20. The plurality of electrodes on at least one of the substrates comprises at least a first electrode and a second electrode, the first electrode and the second electrode each comprising: a plurality of main lines extending in a first direction across the substrate, the main lines of the first and second electrodes being arranged alternately with respect to one another on the substrate; a plurality of branch lines extending from the main lines into the area between the main lines, the branch lines extending into the area between the first main line and the second main line of the first electrode and of the second electrode extending alternately from the first and second main lines and at least one of two successive branch lines extending into the same area extends at least halfway across the area measured along a second direction perpendicular to the first direction; 20. An optical modulator according to claim 1 , comprising:

21. 21. The light modulator of claim 20, wherein two successive branches that extend into the same area between a first main line and a second main line overlap in a second direction when projected in a first direction.

22. 22. An optical modulator as claimed in any one of claims 20 and 21, wherein two successive branches that extend into the same area between the first main line and the second main line have different lengths, the longer branch being at least 5% longer than the shorter branch.

23. 23. A light modulator according to any one of claims 20 to 22, wherein the distance between main lines and successive main lines on the substrate of the first and second electrodes varies in the second direction and / or in the first direction.

24. The distance between the main lines is - an increase towards a maximum distance alternates with a decrease towards a minimum distance, and / or - Increase or decrease by a random amount within the maximum and minimum distances, and / or An optical modulator as claimed in claim 23, wherein a series of distances in the second direction between the main lines across the substrate vary randomly, the sum of the distances being between a minimum total distance and a maximum total distance.

25. a main line and a branch line extending from the main line are made up as a connected continuation of the minor lines from which they extend, the minor lines in the continuation joining to form the main line; - the branches extending on the same side of the secondary main line have equal length, and / or - the branches extending on the same side of a secondary main line are parallel, and / or An optical modulator according to any one of claims 20 to 24, in which the number of branch lines extending from either side of a minor main line is equal.

26. Branch lines extending on the same side of a minor line and branch lines extending from successive minor lines of the same major line are - have different lengths, and / or - forming a different angle with the first direction, and / or An optical modulator according to claim 25, having a different number of branch lines extending from the sides of the secondary main line.

27. 27. The optical modulator of claim 25, wherein an angle between the branch line and the first direction of the minor main line is randomly selected between 45 degrees and 90 degrees.

28. 28. An optical modulator according to any one of claims 25 to 27, wherein a secondary main line and a subsequent connected secondary main line of the same main line are shifted relative to each other in both the first direction and the second direction.

29. 29. An optical modulator as claimed in any one of claims 20 to 28, wherein the pattern in which the first and second electrodes are arranged is subdivided into a set of blocks extending in first and second directions across the substrate, each block comprising a plurality of minor lines that are part of the plurality of main lines of the first electrode and a plurality of minor lines that are part of the plurality of main lines of the second electrode, and at least one of the blocks is repeated multiple times on the substrate.

30. - in a portion of the block the secondary electrodes have multiple branches and in a portion of the block the electrodes do not have multiple branches; and / or 30. An optical modulator according to claim 29, wherein in a part of the block the minor main lines are straight and in a part of the block the minor main lines are wavy.

31. 31. An optical modulator as claimed in any one of claims 1 to 30, wherein the pattern in which the electrodes are arranged is subdivided into a plurality of portions, and at least one of the electrode line spacing, electrode line thickness, electrode line width, electrode material, electrode line shape, and electrode line direction is different in the plurality of portions to cause an optical effect.

32. 32. The optical modulator of claim 1 , wherein an electrode geometry selected from the group consisting of thickness, width, shape, area and volume varies across at least one of the first substrate and the second substrate.

33. the primary electrode is connected in at least a portion to a further secondary electrode running parallel to the primary electrode; a secondary electrode is connected to the primary electrode through a semiconducting layer, the secondary electrode being electrically connected to the primary electrode line by the semiconducting layer, which only allows a transmission current above a threshold voltage on the primary electrode, and / or the secondary electrode is transparent, and / or the secondary electrode comprises a capacitor arranged to locally hold a charge, and / or An optical modulator according to any one of claims 1 to 32, wherein the secondary electrodes comprise a photovoltaic semiconductor material, the secondary electrodes providing electrical power to the primary electrode lines.

34. 34. An optical modulator as claimed in any one of claims 1 to 33, wherein the plurality of electrodes extends across the substrate in two dimensions and in a third dimension at least a first electrode of the plurality of electrodes is spaced apart from at least a second electrode of the plurality of electrodes.

35. 35. An optical modulator as claimed in any one of claims 1 to 34, wherein the electrodes on the first substrate are arranged in at least partially the same pattern as the second electrodes on the second substrate, and the patterns of the first and second electrodes are shifted relative to each other.

36. 1. An optical modulator method, comprising:

1. An optical modulator comprising: a first substrate and a second substrate, the first substrate and the second substrate being arranged with their inner sides facing each other; a plurality of electrodes (110, 120) applied to the inner side of each of the first and second substrates, the electrodes having a surface area facing the opposing substrate; each of the plurality of electrodes is arranged in a pattern across the substrate, each of the plurality of electrodes comprising a plurality of main lines extending in a first direction across the substrate, the main lines of the plurality of electrodes being alternatingly arranged with respect to one another on the substrate; and a plurality of electrodes, at least a part of the surface area of ​​which is provided with a protective coating; an optical layer between a first substrate and a second substrate, the optical layer comprising a fluid containing particles, the particles being charged or chargeable; and To provide selecting an AC current or voltage of one of a plurality of maximum amplitudes corresponding to one of a plurality of levels of transmittance or reflectivity in the light modulator; applying an alternating current to the electrodes to obtain an electromagnetic field between the electrodes, which results in electrophoretic movement of the particles towards or away from the electrodes, causing modulation of the optical properties of the light modulator; An optical modulator method comprising:

37. 37. A transitory or non-transitory computer readable medium comprising data representing instructions that, when executed by a processor system, cause the processor system to perform the method of claim 36.

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