Light modulator and substrate having micro and / or NANO patterned elements for optical modulation

Abstract

Some embodiments relate to a transparent substrate for use in an optical modulator. The substrate has at least one driving electrode applied to a first surface of the substrate. The driving electrode can be patterned across the substrate and can receive a potential, thereby modulating the optical properties of the optical modulator. Patterned elements are applied to the surface of the substrate to alter the phase, amplitude, and / or polarization of light interacting with the substrate.

Description

Technical Field

[0001] The subject matter currently disclosed relates to a substrate used in an optical modulator, a method for manufacturing the substrate, an optical modulator, a method for calibrating the optical modulator, a method for controlling the optical modulator, and a computer-readable medium. Prior Technology

[0002] A known optical modulator is disclosed in WO2022023180, which is incorporated herein by reference. This known optical modulator includes a transparent substrate or a reflective substrate. A plurality of electrodes are applied to the substrate in a pattern across the substrate. A controller can apply a potential to these electrodes to obtain an electromagnetic field between the electrodes, thereby providing electrophoretic movement of particles toward or away from the electrodes. Summary of the Invention

[0003] Having an improved light modulator would be advantageous. Specifically, having an improved transparent substrate for use in the light modulator would be advantageous. In one embodiment of the substrate, micron and / or nanometer patterned elements are applied to the surface of the substrate. These patterned elements alter the phase, amplitude, and / or polarization of light interacting with the substrate. The light interacting with the substrate includes light passing through the surface. The light interacting with the substrate may also include light reflected from the surface.

[0004] These patterned elements have shapes (e.g., 2D or 3D shapes parallel to the substrate) and distributions selected to influence the desired optical modulation. The patterned elements can be manufactured by patterning, which may include a process of creating nanostructures across the surface of a material (in this case, the substrate). In one embodiment, the patterned elements may be transparent or opaque. Transparent patterned elements have the advantage of less transmittance reduction, although the optical effects of the elements may be less (e.g., when the elements have a low refractive index).

[0005] In addition to patterned elements, at least one driving electrode may be applied to a first surface of the substrate, the driving electrode being configured in a pattern across the substrate. The electrodes are configured to receive potential, thereby modulating the optical properties of the light modulator. Specifically, the light modulator may have an optical layer adjacent to the substrate. Particles in the optical layer may be controlled by the electrodes (e.g., electrophoretic control).

[0006] Metasurfaces (e.g., formed by patterned elements) allow for the correction of optical artifacts caused by driving electrodes present on a substrate. Specifically, diffraction and / or rainbow can be reduced by adding nano-elements. For example, metasurfaces may include thin-film coatings that generate electromagnetic optics. Typically, metasurface designs are specifically selected or optimized for electrode designs. Using the same metasurface for different electrode patterns may not be feasible.

[0007] In addition to allowing for artifact correction, metasurfaces (e.g., formed by patterned elements) may also allow for the introduction of optical effects. Optical effects include 3D rendering, holography, and lenses that may have different focal points.

[0008] Metasurfaces are subwavelength-scale nanostructures that can be used to design thin optical devices. Various metasurface-based optical devices (also known as planar optical devices) have achieved different performance levels.

[0009] Nano-devices can be applied to the same surface of a substrate or to opposite surfaces of the substrate.

[0010] Nano-sized components can be configured to reduce substrate reflection, thereby improving the dark state of the light modulator, for example, deepening the black level.

[0011] The currently disclosed object further includes a method for manufacturing a substrate, an optical modulator, a method for calibrating the optical modulator, a method for controlling the optical modulator, and a computer-readable medium. Simple Explanation of the Diagram

[0012] Further details, styles, and embodiments will be illustrated by way of example only in the reference drawings. The components in the drawings are for simplicity and clarity and are not necessarily drawn to scale. In these drawings, components corresponding to those already illustrated may have the same component symbol. In the drawings, Figure 1a schematically illustrates one example of an embodiment of the construction block. Figure 1b schematically shows an example of one embodiment of the substrate. Figure 1c schematically shows an example of one embodiment of the substrate. Figure 1d schematically shows an example of one embodiment of the substrate. Figure 1e schematically shows an example of one embodiment of the substrate. Figure 1f schematically shows an example of one embodiment of the substrate. Figures 2a to 2f schematically illustrate one example of an embodiment of the substrate. Figure 3a schematically illustrates one example of an embodiment of an optical modulator. Figure 3b schematically illustrates one example of an embodiment of an optical modulator. Figure 3c schematically shows an example of one embodiment of a car. Figures 4a to 4c schematically illustrate one embodiment of the optical modulator. Figure 5a schematically illustrates one example of an embodiment of an optical modulator. Figure 5b schematically illustrates one example of an embodiment of an optical modulator. Figure 5c schematically illustrates one example of an embodiment of an optical modulator. Figure 6a schematically illustrates one example of an embodiment of a transparent substrate used in an optical modulator. Figure 6b schematically illustrates one example of an embodiment of a transparent substrate used in an optical modulator. Figure 6c.1 schematically illustrates one example of an embodiment of a transparent substrate used in an optical modulator. Figure 6c.2 schematically illustrates one example of an embodiment of a transparent substrate used in an optical modulator. Figure 6d.1 schematically illustrates an example of an optical modulator without patterned elements. Figure 6d.2 schematically illustrates one example of an embodiment of an optical modulator with patterned elements. Figure 6e.1 schematically illustrates one example of an optical modulator with its conductive patterned elements in an inactive state. Figure 6e.2 schematically illustrates one example of an optical modulator with its conductive patterned elements in operation. Figures 7a to 7g schematically illustrate one example of an embodiment of a transparent substrate used in an optical modulator. Figure 8a schematically illustrates one example of a method for manufacturing a substrate as described in one embodiment. Figure 8b schematically illustrates one example of a method for manufacturing an optical modulator as described in one embodiment. Figure 8c schematically illustrates one example of an embodiment of a method for operating a light modulator as described in one embodiment. Figure 9a schematically illustrates a computer-readable medium having a writable portion including a computer program according to one embodiment. Figure 9b schematically illustrates a representation of a processor system according to one embodiment. The symbols and abbreviations in the [Symbol Explanation] section are for the purpose of interpreting the drawings and should not be construed as limiting the scope of the patent. Implementation

[0013] Although the subject matter disclosed herein may have many different embodiments, one or more specific embodiments are shown in the drawings and will be described in detail herein. It should be understood that this disclosure is intended to be illustrative of the principles of the subject matter disclosed herein and is not intended to limit the subject matter of this disclosure to the specific embodiments shown and disclosed.

[0014] In the following description, for ease of understanding, the elements of the embodiments are illustrated in operation. However, it will be clear that individual elements are configured to perform the functions described for performance by them. Furthermore, the subject matter disclosed herein is not limited to these embodiments, but also includes all other combinations of features described herein or referenced in mutually different subsidiary technical solutions.

[0015] This invention discloses a substrate, for example, used in light modulators (particularly dynamic glass windows). The substrate is transparent, and at least one driving electrode is applied to one side of the substrate, extending in a pattern across one side of the first substrate. Interestingly, when used in a light modulator, it is advantageous to apply patterned elements to the surface of the substrate to modify (e.g., correct) the light system interacting with the substrate. The patterned elements are arranged in a pattern on the substrate. The pattern can be repeated, but is not required to be. The pattern is formed according to the pattern that the light is to be modulated by the patterned elements. For example, a plurality of patterned elements on the substrate can collectively form a metasurface.

[0016] There are many types of optical modulators, such as those using a substrate. Some known optical modulators are based on the principle of electrophoresis. For example, the substrate may include a plurality of interleaved driving electrodes (e.g., two electrodes) applied to the substrate, each of which is arranged in a pattern across the substrate, the interleaved driving electrodes being alternately arranged relative to each other on the substrate. Having a plurality of interleaved electrodes allows for localized control of the electric field, thereby enabling electrophoretic control of particles.

[0017] Electrophoretic optical modulators are explained more broadly herein and used as an example of excitation. In one embodiment, the optical modulator includes a first substrate and a second substrate. According to one embodiment, at least one of the first and second substrates may have patterned elements. For example, the first and second substrates may be configured to face each other internally. For example, using the substrate according to one embodiment has the effect of reducing optical interference. An optical layer is disposed between the first and second substrates. Driving electrodes are disposed to modulate the electric field in the optical layer. The optical layer includes a fluid containing particles, wherein the particles are charged or rechargeable. The particles can be moved under the control of the electric field. For example, a controller may be configured to apply a potential to the driving electrodes to obtain an electromagnetic field at the driving electrodes, thereby providing electrophoretic movement of particles toward or away from at least one of the driving electrodes, thereby causing the optical properties of the optical modulator to be modulated.

[0018] The following sections describe several known optical modulators, demonstrating certain options for techniques and electrodes. These known substrates can be advantageously modified by applying patterned elements. These examples also demonstrate optical modulators with different numbers of electrodes on the substrate.

[0019] International patent applications WO2011012499 A1 (which are incorporated herein by reference) and WO2011131689 (which are incorporated herein by reference) disclose light modulators in the form of electrophoretic display devices (e.g., electronic ink displays). The pixels of the display include an accumulation electrode and a field electrode. The accumulation electrode is disposed at a storage region for accumulating charged particles away from an aperture region, while the field electrode occupies at least a portion of the field electrode region, which is the aperture region of the pixel. The charged particles can move between the accumulation electrode and the field electrode. In one embodiment, both electrodes are applied to a single substrate. The substrate may have patterned elements applied to its surface to modify (e.g., correct) the light interacting with the substrate.

[0020] U.S. Patent 10,921,678, entitled "Electrophoretic device," is incorporated herein by reference. This patent discloses an electrophoresis apparatus having a patterned electrode on only one of two substrates. For example, the substrate with one electrode according to US 10,921,678 can be replaced by a substrate including a single electrode according to one embodiment. For example, one embodiment includes a first transparent substrate having a field electrode and a second substrate having an accumulation electrode opposite the first substrate. The first and second substrates encapsulate pixels with fluid and particles. In use, an electromagnetic field applied to the field electrode and the accumulation electrode provides the movement of particles away from and away from the field electrode and the accumulation electrode, and vice versa. The substrate may have patterned elements applied to the surface of the substrate to modify (e.g., correct) the light interacting with the substrate.

[0021] U.S. Patent 8,054,535B2 (which is incorporated herein by reference) and U.S. Patent 8,384,658B2 (which is incorporated herein by reference) illustrate alternative examples of electrophoretic light modulators in which one of the two substrates has two patterned electrodes.

[0022] Patterned electrodes are also used in dielectric electrophoretic modulators. For example, U.S. Patent Application US2005185104A1 (which is incorporated herein by reference) and U.S. Patent Application US20180239211A1 (which is incorporated herein by reference) disclose dielectric electrophoretic modulators having a substrate containing patterned electrodes. Either of these referenced electrophoretic modulators or dielectric electrophoretic modulators can be adapted by applying patterned elements to the surface of the substrate to modify (e.g., correct) the light interacting with the substrate.

[0023] The paper "Reversible Metal Electrodeposition Devices: An Emerging Approach to Effective Light Modulation and Thermal Management" is included by reference, and also illustrates a substrate on which patterned electrodes are applied. The patterned electrodes can be advantageously configured according to one embodiment.

[0024] One embodiment of the substrate can be used in an electrochromic device (ECD). An electrochromic device (ECD) controls optical properties (electrochromicity) such as optical transmission, optical absorption, optical reflectivity, and / or optical emissivity in a continuous but reversible manner when a voltage is applied. This property enables the electrochromic device to be used in applications such as smart glass, electrochromic mirrors, and electrochromic display devices.

[0025] For example, electrochromic devices have been described in the paper "Silver grid electrodes for faster switching ITO-free electrochromic devices" by António California et al., which is incorporated herein by reference. That paper describes the fabrication of electrochromic devices in which ITO is not present.

[0026] Electrochromic devices utilize conductive electrodes applied to a substrate. The cited paper uses a silver grid made of silver ink as the conductive electrodes. Electrochromic devices may include electrochromic materials. The cited paper uses poly(3,4-ethylenedioxythiophene)polystyrene sulfonate (PEDOT:PSS). In an electrochromic device, at least one driving electrode (e.g., a conductive electrode) is applied to the substrate. The driving electrode is configured across the substrate in a pattern. The cited paper discloses two different grid patterns: a regular honeycomb design and a regular trapezoidal design. See Table 1 and Figure 3 of the cited paper.

[0027] Electrodes can be applied to a substrate by screen printing, in the case of polyethylene terephthalate (PET) in the cited paper. Typically, the electrodes are conductive materials, such as metals or metal oxides. In the cited paper, a RokuPrint RP 2.2 device and a 180-degree wire grid were used to screen print a grid on PET using silver ink. The sample was allowed to dry in an oven at 130°C for 15 minutes. One or two PEDOT:PSS SV3 layers were then screen-printed on top of these silver grids. Patterned elements can be applied to the surface of the substrate, thereby altering the light interacting with the substrate, for example, thus forming a metasurface.

[0028] Another example of an electrochromic device is given in U.S. Patent 5,161,048 entitled "Electrochromic window with metal grid counter electrode and acidic polyelectrolyte," which is incorporated herein by reference. For example, an electrochromic device may include a transparent electrochromic film and an ion-conducting layer disposed between a pair of electrodes. A metal grid electrode is provided for these electrodes. Figure 1 of this patent illustrates the metal grid according to the referenced patent. To form a counter electrode, the metal grid is disposed adjacent to a second glass substrate.

[0029] For example, in one embodiment of an electrochromic device, the electrochromic device may include a transparent substrate, a conductive electrode component, a transparent electrochromic film in contact with the conductive electrode component, an ion-conducting polymer in contact with the electrochromic film, and a patterned conductive electrode in contact with the ion-conducting polymer. The patterned conductive electrode may be according to one embodiment.

[0030] The substrate according to one embodiment can be advantageously applied in several other technologies. For example, the light modulator can be a dielectric photomodulator, such as the dielectric photomodulator shown in US20050185104 A1, which is incorporated herein by reference. The substrate as described in one embodiment can also be used in other electrowetting applications and OLED applications.

[0031] In OLEDs and electrowetting, electrodes are required only on one of the substrates. The substrate having electrodes may be according to one embodiment.

[0032] Typically, in applications using light modulators for glass windows, both substrates are transparent. In other applications (e.g., televisions, e-readers, etc.), only one substrate may be transparent.

[0033] In one embodiment, the substrate has patterned elements applied to the surface of the substrate to modify (e.g., correct) the light interacting with the substrate.

[0034] In Figures 1a to 4c, the nano-element system is not visible in these figures.

[0035] [picture] [1b] An example of one embodiment of the substrate is schematically shown. This substrate is particularly useful in optical modulators (e.g., the type of optical modulator described herein). A plurality of interleaved drive electrodes are applied to the substrate across the substrate. Two types of electrodes are shown in Figure 1b.

[0036] The excitation example of the substrate is used in an electrophoretic light modulator. Typically, an electrophoretic light modulator comprises at least two substrates, each substrate having at least two drive electrodes; however, this is not mandatory. For example, an electrophoretic light modulator may include a single substrate having two electrodes and an opposing substrate having one electrode. In any case, preferably, at least one of these substrates in the light modulator is according to an embodiment.

[0037] One embodiment of an optical modulator includes a first substrate and a second substrate according to an embodiment. The first substrate and the second substrate are configured to face each other from the inside. At least one driving electrode is applied to the inside of the first substrate. An optical layer is disposed between the first substrate and the second substrate. A controller is configured to apply a potential to the at least one driving electrode, thereby modulating the optical properties of the optical modulator. One or both of the first substrate and the second substrate are transparent and / or translucent.

[0038] There are many different types of optical modulators that use at least one driving electrode applied to a substrate. Interference is a common problem in the field of optical modulators when light is transmitted through the substrate. Optical layers and controllers can be configured to modulate optical properties using effects that depend on the potential on the driving electrode; examples include dielectrophoresis and electrophoresis. For instance, optical modulation can include the modulation of particles disposed in the optical layer. The number of driving electrodes can range from one driving electrode on a single substrate to multiple driving electrodes on one or two substrates.

[0039] The optical layer disposed between the first substrate and the second substrate may include particles, such as particles suspended in a fluid. The controller may be configured to apply a potential to the drive electrodes, thereby causing the particles to move and thus modulating the optical properties of the optical modulator.

[0040] In one embodiment, the particles include charged or rechargeable particles, and the controller is configured to apply a potential to the driving electrodes to obtain an electromagnetic field, thereby providing electrophoretic movement of the particles. In another embodiment, the electromagnetic field is configured between at least two driving electrodes disposed on the same substrate or on different substrates.

[0041] In one embodiment, the particles include dielectric particles, and the controller is configured to apply a potential to the driving electrode to apply an electric field gradient to the particles, such that the particles can move under the action of dielectric force.

[0042] The controller can apply electrical signals to one or more of the driving electrodes. Embodiments of controlling the dielectrophoresis force can use signals including DC and / or AC signals.

[0043] Figure 1b shows two driving electrodes on the same surface. These two driving electrodes are indicated in Figure 1b by two different dashed line patterns. More than two electrodes may exist on the same side of the substrate, for example, to facilitate finer-grained control of voltage differences across the substrate. These driving electrodes are applied to the same side of the substrate. The electrodes can be applied to the substrate in the form of photolithography (e.g., using a photomask representing an electrode pattern). Electrodes can also be applied by embedding them into the substrate.

[0044] The drive electrodes are electrically connected, for example, having the same potential at various locations. The drive electrodes may include drive buses and main lines. At least, these main lines are interleaved with the main lines of another drive electrode. Typically, these drive electrodes extend across the substrate along substantially straight lines, while the main lines are spiral.

[0045] In one embodiment, each of the two substrates of the optical modulator has two electrodes disposed on its inner surface. However, as mentioned, it is not necessary to have multiple electrodes on one or more substrates. For example, one embodiment of the optical modulator includes a first substrate and a second substrate. For example, the first substrate may include one driving electrode, and the second substrate may not include a driving electrode. For example, the first substrate may include two driving electrodes, and the second substrate may include one driving electrode. For example, the first substrate may include two driving electrodes, and the second substrate may include two driving electrodes. For example, the first substrate may include more than two driving electrodes, and the second substrate may include two or more driving electrodes.

[0046] However, an optical modulator comprising two drive electrodes in each substrate is used as an excitation example. For example, by connecting the two drive electrodes or by removing one of the drive electrodes, a substrate design characterized by two drive electrodes can be adapted to have a single drive electrode. Adapting the substrate in this way allows it to be used in different technologies.

[0047] Each of a plurality of driving electrodes is configured in a pattern across the substrate. The driving electrodes are arranged alternately on the substrate relative to each other. Typically, the driving electrodes comprise multiple main lines, each extending across the substrate. The main lines of the driving electrodes alternate (e.g., interlaced). For example, in FIG1b, the first driving electrode comprises main lines 111 to 114, and the second driving electrode comprises main lines 121 to 124. Each of these driving electrodes is driven by its own driving bus. FIG1b shows two driving buses: driving bus 110 and driving bus 120. These driving electrodes also serve to connect the main lines together. For example, in FIG1b, driving bus 110 drives and connects main lines 111 to 114; and driving bus 120 drives and connects main lines 121 to 124. More main lines than the four shown in this example may exist. Using several main lines is advantageous because it shortens the length of the electrodes, but it is not necessary. Although having multiple main lines is advantageous, it is possible to design each drive electrode to use only one main line.

[0048] Multiple main lines of the first and second electrodes are arranged alternately on the substrate.

[0049] The excitatory application of a substrate (such as substrate 100) is in smart windows (e.g., light modulators), which can be used in homes, offices, greenhouses, automobiles, and the like. The transparency and reflectivity levels of the smart window can be electrically adjusted. For example, in a smart window, two substrates (such as substrate 100) are stacked such that the sides on which two electrodes are applied face each other. A fluid containing particles is encapsulated between the two substrates. Embodiments of smart windows will be discussed further below. In one embodiment, electrodes (e.g., two or more electrodes) are applied to one surface of each substrate. One, two, or more electrodes may also be present on the other surface of substrate 100, for example, to facilitate the stacking of three or more substrates.

[0050] The following embodiments illustrate examples of modulating transparency or reflectivity levels. The optical modulator can be adapted to other optical effects. For example, embodiments may be modified to use different translucency levels rather than different transparency levels, where desired. The types of particles used in an embodiment may differ, for example, particles that absorb or reflect different wavelengths and particles with different degrees of specular or diffuse reflection. For example, in one embodiment, the optical modulator can modulate different reflection levels. Particles may also emit light. Stacking multiple optical layers further increases the possibilities.

[0051] Having two sets of alternating main lines is sufficient to provide electrically adjustable glass windows; due to the two sets of alternating main lines, the electric field at any part of the substrate can be controlled, because the two opposing electrodes are connected to the portions from the two opposite sides.

[0052] Interestingly, the pattern in which the driving electrodes extend across the substrate is formed by multiple repeating building blocks. As shown in Figure 1b, the driving electrodes on substrate 100 exhibit four substantially identical blocks: blocks 141, 142, 143, and 144. The number of building blocks may be greater than four. These building blocks repeat across the substrate in two directions (e.g., a first direction 191 shown horizontally in the figure, e.g., the x-direction, and a second direction 192 shown vertically in the figure, e.g., the y-direction)). The use of building blocks is advantageous because it allows for manufacturing using a stepper machine; however, the use of building blocks is not mandatory.

[0053] For example, [picture] [1a] An example of one embodiment of a building block 140 is schematically shown. The building block 140 includes a plurality of interleaved electrodes extending across the building block in at least two directions. Four electrodes are shown in FIG1a: electrodes 131 to 134. When these building blocks are repeated across the substrate in two directions, the electrodes in the building blocks will form driving electrodes, for example, multiple main lines forming driving electrodes. It should be noted that these building blocks are typically connected in a substrate electrode design tool. Typically, a building block includes more than four electrode lines. For example, in a series of embodiments, 8 to 12 main lines are used. However, the number of electrode lines can be much higher. For example, the building block may include a number of short electrode lines near the edge, which connect to lines of other building blocks when the block is repeated. Taking into account these short branches, the number of lines can be increased to 50. Obviously, the number of electrode lines can also be increased when using larger building blocks. In one embodiment, the number of electrode lines in the construction block is between 8 and 50, or between 8 and 25, etc.

[0054] The drive electrodes formed by repeated construction blocks are connected to the drive bus. Typically, the electrode lines in a construction block are connected to the electrode lines in an adjacent block by merging corresponding electrode lines; although this is not always necessary, connection bands connecting corresponding electrode lines can be inserted between repeated construction blocks.

[0055] This step connects multiple main lines together, thus forming a single drive electrode. Figure 1b shows two connection zones 119 and 129, where main lines belonging to the same drive electrode are connected to drive bus 110 and drive bus 120, respectively.

[0056] The electrodes shown in Figure 1a are alternately drawn with dashed lines in the same dashed line pattern as in Figure 1b. In practice, in this example, a particular electrode in the construction block of Figure 1a will always end in either the first driving electrode or the second electrode, for example, as indicated by the dashed line pattern in this case. However, this is not always the case. An electrode in the construction block may end as part of the first driving electrode or as part of the second driving electrode. This can be changed, for example, due to the parity of the number of electrodes in the construction block, the repeating pattern of the construction block, etc.

[0057] For example, a specific pattern of repeating building blocks can be used in an optical modulator with two drive electrodes, where alternating main lines can be assigned to the two drive electrodes. However, the same pattern of repeating building blocks can be used in an optical modulator with three drive electrodes, where each subsequent set of three main lines can be assigned to the three drive electrodes.

[0058] Furthermore, the building blocks shown in Figure 1a are square, but this is not mandatory. For example, the building blocks can be rectangular. In one embodiment, the shapes of (a number of) building blocks can form a so-called checkerboard arrangement. For example, the building blocks can be a combination of triangles, hexagons, or even planar filled shapes.

[0059] As described, Figures 1a and 1b are schematic diagrams. This is especially true for the depiction of the electrodes. As shown in Figure 1a, the electrodes are straight; however, in one embodiment, the electrodes on the construction block are more spiraled (e.g., more curved). By adjusting the shape of the electrodes, undesirable diffraction effects can be altered.

[0060] In one embodiment, the dimming mirror includes a light modulator according to one embodiment. For example, the dimming mirror includes a transparent substrate, an optical layer, and a reflective substrate. One or both of the substrates are according to one embodiment. The dimming mirror may be electrophoretic. Typically, each substrate has two electrodes, but this is not mandatory.

[0061] [picture] [1c] An example of one embodiment of substrate 101 is schematically shown. Substrate 101 is similar to substrate 100, except that the main lines formed by the electrodes on the building blocks are connected to the drive buses. In FIG. 1b, connecting bands are inserted between the repeating building blocks and the drive buses 110 and 120. In the connecting bands, main lines belonging to the same drive electrode are connected to the same drive bus. In FIG. 1c, the drive buses are directly adjacent to the building blocks. To avoid connecting the drive buses to the main lines of different drive electrodes, some parts of the building blocks are modified.

[0062] For example, construction block 141 may be a copy of construction block 140, but electrode 134 is shortened so that main line 122 (of which line 134 is a part) is not connected to bus 110. In FIG. 1c, the construction blocks are substantially the same except for introducing disconnections in some electrodes of the construction blocks immediately adjacent to the drive bus to avoid connecting the main line to the drive bus. Although all construction blocks shown in FIG. 1c are modified in this manner, in one embodiment most construction blocks (e.g., construction blocks not adjacent to drive buses 110, 120) are not modified.

[0063] [picture] [1d] An example of one embodiment of a substrate 102 is schematically shown. In one embodiment, electrodes in a construction block are each connected to the same opposite side of the construction block. This results in a main line formed by the electrodes on the construction block connecting the opposite sides of the substrate. In this case, only two drive buses (e.g., each extending along the opposite side of the substrate) are sufficient to connect and drive the drive electrodes.

[0064] However, it is not necessary for electrodes in a building block to connect to opposite sides of the building block. Although typically all electrodes in a building block will connect to both sides of the building block, these two sides do not need to be opposite. This is because the electrodes can be continued from the next building block. In this case, most main lines will still connect to the same two opposite sides, but this may not be the case at the edges of the substrate, because there are no other building blocks there to advance the electrodes forward. To allow for more complex electrode designs on the building blocks, main lines can be connected to drive buses from two sides (e.g., the two sides of the substrate adjacent to the same corner of the substrate).

[0065] Figure 1d shows a drive bus 110' extending along two sides of the substrate and a drive bus 120' extending along the other two sides of the substrate.

[0066] The advantage of this configuration is that the drive buses can be made in the same plane, although this is not mandatory. Ideally, the drive buses can be connected from three or all four sides to, for example, further increase the design freedom of the building blocks. Various examples are given in this article.

[0067] It should be noted that overlapping of drive electrodes (e.g., drive buses) and / or main lines is permitted. This is possible, for example, by introducing a portion of dielectric material between the electrodes. For instance, these overlapping electrodes may be partially or completely located in different planes of the substrate.

[0068] For example, in one embodiment, a first driving electrode may be deposited. Then, a dielectric layer is locally deposited, and finally, a second driving electrode is deposited. The dielectric layer is configured to at least cover the points where the first and second electrodes intersect. Vias may be used for the first driving electrode, for example, to connect to the first driving electrode. The deposited driving electrode may include a deposited driving bus.

[0069] [picture] [1e] An example of one embodiment of the substrate 203 is shown schematically. In FIG1e, the construction blocks have been copied multiple times.

[0070] Mirror construction block 211 along the y-direction to form construction block 221. Place construction block 221 directly at the bottom of construction block 211. Mirror construction block 211 along the x-direction to form construction block 212. Place construction block 212 directly to the right of construction block 211. Mirror construction block 211 along both the x and y directions to form construction block 222. For example, mirroring can use one side of the construction block as the mirror axis.

[0071] By constructing the blocks in a mirrored manner, it is ensured that the drive buses of the same drive electrode are close to each other on the substrate.

[0072] [picture] [1f] An example of one embodiment of substrate 204 is schematically shown. In substrate 204, building blocks are repeated across the substrate in different ways. Building block 251 is mirrored along the y-direction to form building block 261. Building block 261 is disposed directly at the bottom of building block 251. Building block 251 is point-reflected (e.g., rotated 180 degrees) to form building block 252. Building block 252 is disposed directly to the right of building block 251. Building block 251 is mirrored along the x-direction to form building block 262.

[0073] [picture] [2a] [To the image] [2f] Schematic examples of substrates having interleaved electrodes are shown. Such examples can be embodied on substrates having two electrodes, for example, by means of alternatingly connected electrodes. Figures 2a to 2d can also be embodied on substrates having multiple electrodes, for example, by means of a sequence of three or four or more electrodes connected together.

[0074] Figures 2e and 2f illustrate designs with two driving electrodes on the surface of the substrate. Each design can be modified to have only a single driving electrode on the surface of the substrate, for example, by removing one of the two driving electrodes. For instance, this modified design can be used in an optical modulator using a substrate with a single electrode.

[0075] The demonstrated designs can be implemented in a single plane without intersecting electrodes. Specifically, if such designs are connected to two drive buses, intersecting electrodes are not required. When using more than two drive electrodes, or if using more complex electrode patterns, electrode intersections may be used, or even necessary. However, such intersections are possible, for example, at the location where two electrode lines intersect, a dielectric material can be disposed between the electrodes. For example, an insulator can be deposited at the intersection location. For example, the first drive electrode is located in a first plane of the substrate, and the second drive electrode is located in a second plane of the substrate.

[0076] According to one embodiment, two substrates can be combined to form a light modulator. This light modulator is particularly suitable for glass windows. Exemplary embodiments of the light modulator will be shown below.

[0077] [picture] [3a] Schematic illustration of one embodiment of a light modulator 10, which can be applied to a smart window.

[0078] Reference is made to patent application PCT / EP2020 / 052379, which is incorporated herein by reference; this application includes advantageous designs of optical modulators that can be further improved, for example, by including electrodes, building blocks and / or substrates as explained herein.

[0079] The light modulator 10 can electronically switch between a transparent state and a non-transparent state, and vice versa, or between a reflective state and a non-reflective state, and vice versa. The light modulator 10 includes a first substrate 11 and a second substrate 12 arranged opposite to each other. At least two electrodes are applied to the inner side of the first substrate 11: shown as electrodes 13a and 13b. These at least two electrodes are collectively referred to as electrode 13. At least two electrodes are applied to the inner side of the second substrate 12: shown as electrodes 14a and 14b. These at least two electrodes are collectively referred to as electrode 14.

[0080] A fluid 15 is provided between the substrates. The fluid includes particles 30, such as nanoparticles and / or microparticles, wherein these particles are charged or rechargeable. For example, the particles may inherently carry a charge on their surface. For example, the particles may be surrounded by charged molecules.

[0081] The electrodes are configured to drive particle 30 toward or away from the electrodes, depending on the applied electric field. The optical properties of the light modulator (especially transparency or reflectivity) depend on the position of particle 30 in the fluid. For example, a connector may be provided to apply an electromagnetic field to the electrodes.

[0082] Although two electrodes 13 and 14 are schematically shown in the figures, at least one, but preferably both electrodes 13 and 14 are according to an embodiment.

[0083] In one embodiment, at least one of the electrode patterns on the first substrate and the electrode patterns on the second substrate has a low computational pixelation noise metric, which contributes to low diffraction. Interestingly, the electrode patterns on the substrates may not individually meet their pixelation noise metric limits, but the combination of such electrode patterns (i.e., their superposition) may. Since this pattern is invisible when viewed through an optical modulator, the low pixelation noise metric in the superposition also contributes to low diffraction. Suitable limits for the patterns on the first and / or second substrates or the superposition include: less than 6.05%, 5%, or 4%.

[0084] In one example, apart from the electrodes, substrates 11 and 12 may be optically transparent, typically with a transparency >95% at the relevant wavelength, such as >99%. The transparency may be much lower, for example, 70%, considering the electrodes. The term "optical" may, where appropriate, refer to wavelengths visible to the human eye (about 380 nm to about 750 nm), and may refer to a broader range of wavelengths, including, where appropriate, infrared (about 750 nm to about 1 µm) and ultraviolet (about 10 nm to about 380 nm) and subselectively thereof. In an exemplary embodiment of the optical modulator, the substrate material is selected from glass and polymers.

[0085] In another example, when the top substrate 11 is transparent, one substrate (such as the bottom substrate 12) may be reflective or partially reflective. The optical properties of the light modulator (especially the reflectivity) depend on the position of the particles 30 in the fluid. When the panel is in the open state (vertically driven), the particles will be mostly located between the opposing electrodes of the two substrates, allowing incident light to pass relatively unobstructed through the transparent top substrate and optical layer, and to be reflected or partially reflected on the bottom substrate.

[0086] Typically, the distance between the first substrate and the second substrate is 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, more preferably less than 100 µm, and even more preferably less than 50 µm, such as less than 30 µm.

[0087] In one example, the modulator may be housed in a flexible polymer, and the remainder of the device may be housed in glass. The glass may be rigid or flexible. If necessary, a protective layer may be provided on the substrate. If more than one color is available, more than one flexible polymer layer may be provided. The polymer may be polyethylene naphthalate (PEN), polyethylene terephthalate (PET) (with a SiN layer, depending on the case), polyethylene (PE), etc. In yet another example, the device may be housed in at least one flexible polymer. Thus, the modulator can be attached to any surface, for example, by using an adhesive.

[0088] Particle 30 can be adapted to absorb light, thereby preventing the passage of certain wavelengths. Particle 30 can reflect light; for example, reflection can be specular reflection, diffuse reflection, or something in between. Particles can absorb certain wavelengths and reflect others. Particles can also, or alternatively, emit light using phosphorescence, fluorescence, or similar methods. Even fluids can emit light, with the emissivity modulated by changing the position of the particles.

[0089] In one exemplary embodiment of the light modulator, the size of the nanoparticles ranges from 20 nm to 1000 nm, preferably from 20 nm to 300 nm, and more preferably less than 200 nm. In one exemplary embodiment of the light modulator, the nanoparticles / microparticles may include a coating on a pigment, and preferably include a core. In one exemplary embodiment of the light modulator, the particle coating is made of a material selected from conductive and semiconductive materials.

[0090] In one exemplary embodiment of the optical modulator, the particles are adapted to absorb light with wavelengths from 10 nm to 1 mm (such as 400 nm to 800 nm, 700 nm to 1 µm and 10 nm to 400 nm), and / or adapted to absorb (filter) a portion of light and combinations thereof with wavelengths in the range of 10 nm to 1 mm.

[0091] In one exemplary embodiment of the optical modulator, the particles are charged or rechargeable. For example, the charge on the particles may be 0.1e to 10e per particle (5*10-7-0.1 C / m2).

[0092] In one exemplary embodiment of the optical modulator, the fluid volume is from 1 g / m² to 1000 g / m², preferably from 2 g / m² to 75 g / m², more preferably from 20 g / m² to 50 g / m², such as from 30 g / m² to 40 g / m². A significant advantage is that, with this arrangement, much less fluid and, equally much fewer particles, can be used.

[0093] In one exemplary embodiment of the optical modulator, the particle amount is from 0.01 g / m² to 70 g / m², preferably from 0.02 g / m² to 10 g / m², such as from 0.1 g / m² to 3 g / m².

[0094] In one exemplary embodiment of the optical modulator, the particles have colors selected from cyan, magenta, and yellow, and from black and white, and combinations thereof.

[0095] In one exemplary embodiment of the optical modulator, the fluid includes one or more of a surfactant, an emulsifier, a polar compound, and a compound capable of forming hydrogen bonds.

[0096] Fluid 15 may be a nonpolar fluid with a dielectric constant less than 15. In one exemplary embodiment of the optical modulator, the fluid has a relative constant εr of less than 100, preferably less than 10, such as less than 5. In one exemplary embodiment of the optical modulator, fluid 15 has a dynamic viscosity greater than 10 mPa·s.

[0097] Electrodes 13a, 13b and 14a, 14b are in fluid contact with a fluid. The fluid may be in direct or indirect contact with the electrodes; for example, the fluid may contact the second medium having the electrodes through a porous layer. In one embodiment, the electrodes cover approximately 1% to 30% of the substrate surface. In one embodiment, the electrodes comprise a conductive material having a resistivity of less than 100 nΩm at 273 K (for comparison, commonly used ITO has 105 nΩm), which is similar to a conductivity of >1*107 S / m at 20°C. In one embodiment of the optical modulator, the electrodes comprise copper, silver, gold, aluminum, graphene, titanium, indium, and combinations thereof, preferably copper. The electrodes may be in the form of microfilaments embedded in a polymer-based substrate; for example, copper microfilaments.

[0098] A connector for applying an electromagnetic field to electrodes, wherein the electromagnetic field applied to the electrodes facilitates the movement of nano- and micron-sized particles from a first electrode to a second electrode, and vice versa. A connector for applying an electromagnetic field to electrodes can be provided. For example, in an exemplary embodiment of an optical modulator, the current is between -100 µA and +100 µA, preferably between -30 µA and +30 µA, and more preferably between -25 µA and +25 µA. For example, a power supply can be electrically connected to at least two electrodes. The power supply can be adapted to provide waveform power. At least one of the amplitude, frequency, and phase can be adjusted to provide different states in the optical modulator. For example, a controller can adapt the state of the power.

[0099] The optical modulator 10 may include one or more segments, each segment being a single optically switchable entity, and the segments may be of different sizes. A substrate encapsulates a volume, which may at least partially constitute one segment.

[0100] This device may include driver circuitry for altering the appearance of (individual) segments by applying an electromagnetic field. This can also alter the appearance of a light modulator or one or more portions thereof. For example, a segment may have an area of ​​at least 1 mm². This design allows for stacking to accommodate more colors; for example, for full-color applications, a stack of two or three modulators can provide most or all of the colors respectively.

[0101] Having one or more sections allows for localized control of the light modulator; this is advantageous for some applications, but not essential. For smart windows, the light modulator can be used segmented or unsegmented. For example, when applied to smart windows, transparency or reflectivity can be locally controlled to, for instance, block sunspots without reducing the overall transparency or reflectivity of the window. The sections can be relatively large, for example, having a diameter of at least 1 mm or at least 1 cm, etc.

[0102] In one exemplary embodiment of the optical modulator, substrates (11, 12) are aligned, and / or electrodes (13, 14) are aligned. For example, electrodes 13a, 13b and electrodes 14a, 14b may be aligned relative to each other. In the aligned substrates, when viewed along a direction orthogonal to the substrates, the electrodes on different substrates are positioned one in front of the other. When the optical modulator is disassembled and all substrates are provided with upward-facing electrodes, the electrode patterns are mirror images of each other.

[0103] Aligning the substrates can increase the maximum transparency or reflectivity of the light modulator. On the other hand, when selecting a light modulator based on a wider range of criteria than just transparency or reflectivity, misalignment or incomplete alignment of the two substrates may be preferable. Light modulators can be stacked. For example, two stacked light modulators can be made from three substrates, with the middle substrate having electrodes on both of its surfaces. In one embodiment of the light modulator, depending on the situation, one of the substrates 11 and 12 of the first light modulator is the same as the substrate 11 or 12 of at least one second light modulator. For stacked modulators, alignment can also increase maximum transparency or reflectivity, but this may be detrimental to other considerations, such as diffraction.

[0104] [picture] [3b] One embodiment of the optical modulator 40 is schematically shown. The optical modulator 40 is similar to the optical modulator 10 except that it includes multiple optical layers; in the example shown, it has two optical layers. More than two optical layers may exist. Each optical layer is disposed between two substrates. The optical modulator 40 can be viewed as a stack of dual-substrate type optical modulators as shown in FIG3a. As shown, the optical modulator 40 includes three substrates: a first substrate 41, a second substrate 42, and a third substrate 43. Optical layers are located between substrates 41 and 42, and between substrates 42 and 43. These optical layers may be similar to those in the optical modulator 10. A controller 46 is configured to control the current on the electrodes of the substrates. For example, in FIG3b, the controller 46 may be electrically connected to at least 4 by 2 equals 8 electrodes.

[0105] Interestingly, the particles in multiple optical layers can be different, allowing multiple layers to be used to control more optical properties of the light modulator. For example, particles in different optical layers can absorb or reflect different wavelengths, thus having different colors. This can be used by controller 46 to form different colors and / or different color intensities on the panel. For example, a quad-substrate panel can have three optical layers containing particles of different colors (e.g., cyan, yellow, and magenta). By controlling the transparency or reflectivity of different colors, a wide color spectrum can be formed.

[0106] For example, in one embodiment, the surface of the substrate facing another substrate may have two or more patterns. For instance, outer substrates 41 and 43 may receive electrodes only on the inner side, while the inner substrate (e.g., substrate 42) may have electrodes on both sides.

[0107] Substrates 41 and 42 can be considered together as one embodiment of an optical modulator. Similarly, substrates 42 and 43 can be considered together as one embodiment of an optical modulator.

[0108] [picture] [3c] An example of an embodiment of a car 20 having a smart glass window serving as window 21 is schematically shown. This is a particularly advantageous embodiment because the level of incident light can be changed frequently and rapidly while driving. Using a smart glass window in a car has the advantages that the light level can be maintained at a constant level by adjusting the transparency of the car window. Furthermore, it improves safety by reducing driver distraction due to reduced diffraction effects. The car 20 may include a controller configured to control the transparency or reflectivity of window 21.

[0109] Smart windows can also be used in other window applications, especially those with variable light input (e.g., buildings, offices, residences, greenhouses, skylights). Skylights are windows installed in the ceiling to allow sunlight into the room.

[0110] An optical modulator can have two optical states, such as a transparent state and a non-transparent state, or a reflective state and a non-reflective state. An optical modulator (e.g., optical modulator 10 or optical modulator 40) can be configured to: - A second optical state (e.g., a non-transparent state or a non-reflective state) is switched by forming an alternating voltage on at least one of the first and second substrates, and by applying an alternating current between at least the first and second electrodes on the first substrate and / or between the first and second electrodes on the second substrate. - A first optical state (e.g., transparent state or reflective state) is switched by forming an alternating voltage between the first substrate and the second substrate, applying an alternating current between the first electrode on the first substrate and the first electrode on the second substrate, and / or applying an alternating current between the second electrode on the first substrate and the second electrode on the second substrate.

[0111] The electrode pattern on the first substrate is configured to have at least partially the same pattern as the second electrode on the second substrate. Typically, these electrodes are opposite to each other, but the patterns of the first and second electrodes may also be shifted relative to each other.

[0112] A protective coating may be provided on at least a portion of the inner surface region of at least one of the first substrate and the second substrate.

[0113] The drive signal applied to the drive electrode typically has a varying voltage. For example, the power supply can operate at an AC frequency to switch between a transparent state and a non-transparent state. This signal can have a frequency, for example, between 1 Hz and 1000 Hz. By continuously switching the polarities of electrodes with opposite charges on the first substrate and the second substrate and / or between the first substrate and the second substrate, a balanced electrolytic current can be obtained.

[0114] [picture] [4a] [To the image] [4b] A side view schematically illustrates one embodiment of an optical modulator in use. An electric field is applied to electrodes on the substrate, causing particles to become electrically charged. Using this effect, particles can move around, and thus different transparency or reflectivity states can be formed in the optical modulator. A controller can control the electric field, for example, its amplitude, frequency, and phase. In one embodiment, the controller is connected to at least four electrodes: two electrodes per substrate. However, more electrodes can be used with and connected to the controller; for example, the substrate can use more than two electrodes to better fine-tune grayscale and drive to a non-transparent or non-reflective state. Multiple electrodes can also be used to support multiple segments on the substrate.

[0115] [picture] [4a] Showing an optical modulator without an applied electric field. In Figure 4a, no electricity has been applied to the particles 30 suspended in the fluid 15.

[0116] In the configuration shown in Figure 4a, the conductive electrode pattern disposed on the top substrate is completely or substantially aligned with the conductive electrode pattern on the bottom substrate. The conductive electrode pattern may be deposited on a transparent glass substrate or a (partially) reflective glass substrate, or may be embedded in a plastic substrate, etc.

[0117] Alignment between the top and bottom electrode patterns helps achieve a wider range of achievable transparency or reflectance levels. However, alignment is not mandatory, as a similar effect can be obtained without alignment. A certain range of transparency or reflectance can also be achieved without alignment.

[0118] It should be noted that in these examples, the terms "top substrate" and "bottom substrate" are used to refer to the higher or lower substrate on the page. For example, the same substrate can also refer to the front substrate and the rear substrate, because in glass window applications, the substrates are aligned vertically rather than horizontally.

[0119] [picture] [4b] An optical modulator is shown in which, for example at example P1, a potential of +V1 is applied to each microfilament electrode on the top substrate, and a negative voltage (e.g., -V1) is applied to each microfilament electrode on the bottom substrate. Thus, in this case, the same positive potential is applied to all electrodes 13, and the same negative potential is applied to electrode 14. The potential difference causes negatively charged particles to flow to the vicinity of the electrodes on the top substrate, wherein these particles will substantially align with the top electrodes. Thus, if both the top and bottom substrates are transparent, the transparency of the optical modulator 10 will increase. Similarly, if, for example, the top substrate is transparent and the bottom substrate is reflective, the reflectivity of the optical modulator 10 will increase. If the solution contains positively charged particles, these positively charged particles will flow to the vicinity of the electrodes on the bottom substrate, wherein these particles will substantially align with the bottom electrodes.

[0120] In the second example P2 of the ON state, compared to example P1, reversing the voltages of the top and bottom electrodes achieves a similar level of transparency or reflectivity. In example P2, each electrode on the top substrate now has a negative potential -V1, while the aligned electrode on the bottom substrate has a positive potential. This state is similar to that shown in Figure 4b, but the top and bottom substrates are reversed. In this configuration, the transparency or reflectivity of the light modulator 10 is also high.

[0121] Interestingly, by switching between the positive potential at the electrodes on the top substrate (e.g., the negative potential on electrode 13 (and electrode 14) shown in Figure 4b) and the positive potential at the electrodes on the bottom substrate (e.g., electrode 14 shown in Figure 4b), transparency or reflectivity can be maintained while reducing corrosion damage to the electrodes. This alternating electric field can be achieved by applying alternating potentials to the top and bottom electrodes.

[0122] Applying a waveform is optional, but it is a useful measure to extend the life of the optical modulator by reducing corrosion. For example, corrosion can occur when copper electrodes are used because copper ions dissolve in an ionic fluid on one substrate and flow to the electrode on the opposite substrate, where they deposit. By applying a waveform, the direction of copper ion transport can be frequently reversed, thus reducing corrosion damage. Between examples P1 and P2, the corrosion current between the two substrates is balanced or substantially balanced (e.g., >95%). For example, as the corrosion rate of the top electrode occurs, the copper deposition on the bottom electrode reaches equilibrium between each time point in example P1, and vice versa in example P2. Therefore, particles continuously change or migrate between the top and bottom electrodes, and the optical modulator or smart window is always on, while the dynamic electrolytic current between the top and bottom electrodes is constant. Therefore, there is no net loss or negligible net loss of electrode material on the top and bottom substrates.

[0123] [picture] [4c] This illustrates a method for achieving a reduced transparency state or a reduced reflectivity state. An alternating current voltage is applied to the same substrate. For example, in one embodiment, a potential +V2 is applied to the first electrode, and the next immediately following electrode has an opposite potential -V2, etc., as shown in FIG8c. This can be achieved by applying a potential +V2 to electrode 13a and an opposite potential -V2 to electrode 13b. On opposing substrates, a potential +V2 can be applied to electrode 14a and an opposite potential -V2 to electrode 14b. For example, these electrodes can be configured such that electrodes on the substrates are aligned; electrodes on the top substrate have electrodes opposite to those on the bottom substrate, and vice versa. For example, to reduce transparency or reflectivity, opposing electrodes can receive the same potential, while adjacent electrodes receive opposite potentials. FIG4c shows an embodiment where four electrodes are indicated by element symbols 13a, 13b, 14a, and 14b, and the remaining electrodes continue to alternate.

[0124] By using this AC drive cycle between the top and bottom substrates, a diagonal and lateral electric field is generated between the two substrates, causing disordered particle diffusion, thereby forming the off state of the light modulator. Due to this configuration, particles migrate diagonally and laterally between the top and bottom substrates, and the diffusion of particles into the visible aperture of the light modulator contributes to the off, opaque state of the light modulator.

[0125] For the transparent state shown in Figure 4b, a waveform can be applied to the electrodes, for example, to change the positive potential of the electrodes shown in Figure 4b to a negative potential, and vice versa. As shown in Figure 4b, for example, a waveform is applied between electrodes 13a and 13b and between electrodes 14a and 14b to reduce corrosion damage to the electrodes.

[0126] The AC drive cycle can be implemented by using the staggered line configuration of the top and bottom electrode configurations shown in the planar diagrams of Figures 1a, 1b, 2a to 2f, etc.

[0127] The degree to which transparency or reflectivity increases or decreases in Figures 4b and 4c depends on the voltage difference and frequency difference. By changing the voltage difference, the amount by which transparency or reflectivity increases or decreases can be controlled. For example, a curve representing the relationship between light transmission and voltage can be determined (e.g., measured). To obtain a specific light transmission level (e.g., a specific transparency, e.g., a specific grayscale level), a corresponding voltage (e.g., AC voltage) can be applied. By interpolating the signal into a transparent state or into a non-transparent state, a level between transparent and non-transparent can be obtained. Similarly, a curve representing the relationship between light reflection and voltage can be determined (e.g., measured). To obtain a specific reflectivity level, a corresponding voltage (e.g., AC voltage) can be applied. By interpolating the signal into a reflective state or into a non-reflective state, a level between reflective and non-reflective can be obtained.

[0128] Optical modulators can use different electrode patterns. Each of these electrode patterns can provide a certain range of grayscale (e.g., transparency or reflectance levels) achievable by the optical modulator. However, the grayscale range for a particular electrode pattern may differ from that of another electrode pattern. In other words, although different patterns provide increased transparency or reflectance or increased opacity, the accurate response to a drive signal depends on many factors, including the specific pattern used. Variations in the optical properties of the optical modulator can have fine resolution, for example, less than 1 mm. It should be noted that pixelation of the optical modulator is not required to achieve the different optical patterns (e.g., markings) visible within the optical modulator.

[0129] This effect can be used to embed visible images into an optical modulator by locally altering the electrode pattern on the substrate of the modulator. For example, due to different electrode patterns, gray levels with permanent offsets relative to each other can be locally created. For example, by locally changing the electrode pattern or its spacing, maximum transparency or reflectivity can be altered.

[0130] Therefore, regions on the light modulator have different grayscale intensities, for example, different grayscale levels or different color intensities. However, the region may have the same color point. In one embodiment, these regions may switch together with the rest of the window, but at different rates. For example, due to different electrode patterns, even if the same voltage is applied to the electrodes in two different regions, these electrode patterns result in different transparency states, for example, different transmission levels. For example, the curve representing the relationship between transmission and voltage can be shifted. For example, if the voltage control is changed in the same way in both regions, the light transmission in the two regions can be changed, but by different amounts. By reducing the electrode density, a region can also be made less responsive to the drive signal; specifically, for example, by not applying electrodes to a region, that region can be made not to switch at all.

[0131] For example, electrode materials can be copper, aluminum, gold, indium tin oxide (ITO), etc. ITO is transparent, while Cu / Al is reflective; therefore, different electrode materials can achieve different appearances, regardless of voltage driving. Similarly, different materials with different resistances will produce different electric fields. For example, even with the same voltage driving, ITO has a smaller electric field.

[0132] One embodiment of the method for modulating light includes applying a potential to a plurality of driving electrodes applied to two opposing substrates according to one embodiment to obtain an electromagnetic field between the plurality of driving electrodes, thereby providing electrophoretic movement of particles toward or away from one of the plurality of driving electrodes, thereby causing modulation of light passing through the substrates, wherein the two opposing substrates are as in one embodiment.

[0133] This document describes an optical modulator including a first substrate according to one embodiment. For example, the first substrate may be transparent and has driving electrodes and patterned elements applied to it. The driving electrodes may be configured for electrophoretic and / or dielectrophoretic control of particles in the optical layer of the optical modulator.

[0134] The optical modulator may include a second substrate. The second substrate may also have patterned elements, or it may be a conventional substrate without patterned elements. Having patterned elements in at least one substrate (e.g., a first substrate) provides control over light diffraction and is an improvement over known optical modulators. Furthermore, both substrates (e.g., a first substrate and a second substrate) may have optically active elements to provide additional control.

[0135] In one embodiment, the second substrate may be non-transparent, for example, opaque. This embodiment could be used, for example, in a dynamic mirror or electronic reading system. Typically, particularly in smart window applications, both the first and second substrates are transparent.

[0136] [picture] [5a] An example of one embodiment of an optical modulator 501 is schematically shown. The optical modulator 501 includes a first transparent substrate 511 and a second transparent substrate 512. An optical layer 524 extends between the first transparent substrate 511 and the second transparent substrate 512. Particles 523 are present in the optical layer 524, and these particles affect the optical appearance of the optical modulator. At least one driving electrode 521 is applied on the first substrate 511. The optical properties of the optical modulator can be modified by applying a potential to the at least one driving electrode 521. In the illustrated example, at least one driving electrode 522 is also applied on the second substrate 512.

[0137] The optical modulator is shown in a state where the particles and electrodes are aligned. This state typically corresponds to the most transparent state of the optical modulator. In another state of the optical modulator, the particles can be dispersed throughout the optical layer 524. This state typically corresponds to the most opaque state of the optical modulator. Depending on the properties of the particles, this state can be opaque, for example, absorbing light, or it can be reflective, for example, reflecting light.

[0138] The surface of substrate 511 or 512 facing optical layer 524 is referred to as the first surface.

[0139] At least one driving electrode 521 is configured in a pattern across substrate 511. At least one electrode 521 is configured to receive a potential, thereby modulating the optical properties of the light modulator. At least one driving electrode 522 is configured in a pattern across substrate 512. At least one electrode 522 is configured to receive a potential, thereby modulating the optical properties of the light modulator.

[0140] In a preferred optical modulator, for example, in a preferred embodiment of the optical modulator shown in FIG. 5a, at least two driving electrodes are applied to a first substrate 511 and at least two driving electrodes are applied to a second substrate 512. In this preferred optical modulator, the particles 523 in the optical layer 524 are charged and can move under the control of an electrophoretic force, which can be modified by electrodes on the substrate.

[0141] Patterning element 541 is applied to the surface of substrate 511, thereby altering the phase, amplitude, and / or polarization of light interacting with the substrate. That is, the surface of substrate 511 is configured to possess optical properties that transform the substrate into a so-called metasurface. In this case, patterning element 541 is applied to a second surface of substrate 511 (e.g., the surface opposite to the surface carrying at least one electrode 521). For example, the patterning element may be an optical element with a diameter less than one micrometer parallel to the substrate. Patterning is a process of creating micrometer and / or nanometer structures across the surface of a material (referred to as a substrate).

[0142] Patterning elements 542 are applied to the surface of substrate 512, thereby altering the phase, amplitude, and / or polarization of light interacting with the substrate. That is, substrate 512 also has a metasurface. In this case, patterning elements 542 are applied to a second surface of substrate 512 (e.g., the surface opposite to the surface carrying at least one electrode 522). While having patterning elements 542 on a second substrate is advantageous, as it provides more control, it is not mandatory.

[0143] Micron-patterning and / or nano-patterning are processes that create nanostructures across the surface of a material (called a substrate).

[0144] The optical modulator 501 further illustrates a spacer 531. This spacer ensures that the optical modulators are held at a desired distance from each other. For example, the spacer may be made of the same material as the substrate, and several spacers may be distributed across the substrate. The spacer is optional; for example, instead of spacers, a boundary may be configured around the substrate to hold the substrate at a specific desired distance.

[0145] The advantage of distributing nanoparticles on a second surface of the substrate (e.g., on a side other than the surface with the driving electrode) is that the distribution of optical elements does not interfere with the photoelectrode, and vice versa.

[0146] [picture] [5b] An example of one embodiment of the light modulator 502 is schematically shown. Except that, in this example, the patterned elements are configured to be the same size as the driving electrodes, the light modulator 502 is similar to the light modulator 501. FIG. 5b shows a patterned element 543 on a first surface of substrate 511. FIG. 5b shows a patterned element 544 on a first surface of substrate 512.

[0147] Having patterned elements on the same side as the surface allows the patterned elements to face the optical layer. This protects the patterned elements from damage (e.g., abrasion).

[0148] In the example shown in Figure 5b, both substrates are provided with patterned elements, but it is not necessary for both substrates to be provided in this way.

[0149] Figure 5c schematically illustrates one example of an embodiment of an optical modulator. Except for the change in the position of the particles within the optical layer, the optical modulator shown in Figure 5c is identical to the optical modulator in Figure 5b. This can be achieved by applying a control signal to a drive electrode applied to an electrode on the substrate. It should be noted that the optical effects of the patterned elements can therefore vary. Various methods exist to handle this effect. A first option is to accept the effect. In this case, the patterned elements can be optimized for average and / or frequently occurring conditions (e.g., most transparent, least transparent). A second option is to also apply a control signal to the patterned elements to modify their effect, for example, to create a counteracting effect within the patterned elements.

[0150] [picture] [6a] Schematic illustration of one example of an embodiment of a transparent substrate 601 used in an optical modulator (e.g., optical modulator 501, optical modulator 502 or any other optical modulator according to an embodiment).

[0151] Substrate 601 schematically shows two driving electrodes: driving electrode 611 and driving electrode 612. These two driving electrodes are arranged in an interleaved pattern. Therefore, localized control of the electric field can be applied across the substrate, and thus localized control of the electrophoretic movement of particles can be applied. The metasurface can also be applied in other types of optical modulators.

[0152] Figure 6a shows patterned elements. Patterned elements are arranged in a pattern across the substrate according to the desired specific optical effect. A virtual cut line 631 is also shown in Figure 6a. Optical modulators 501 and 502 can be considered as cross-sections obtained across line 631. Note that spacer 531 is not shown in Figure 6a.

[0153] For example, the patterned elements shown in Figures 6a, 5a, 5b, and elsewhere are two-dimensional or three-dimensional objects with nano-geometry. Typically, the patterned elements protrude from the surface. The shape and distribution of the patterned elements alter the optical properties of the substrate. Sometimes, this is referred to as a metasurface. The optical properties of metasurfaces can be calculated using optical simulation software.

[0154] Patterned elements on a substrate can have various sizes, shapes, and / or materials. For example, a patterned element can be obtained by displacing a two-dimensional shape parallel to the substrate surface away from the substrate surface into a third dimension. For example, the two-dimensional shape can be a polygon, a circle, an ellipse, and the like. The shape of the patterned element can vary in the third dimension. The patterned element can be cylindrical, elongated, and / or curved.

[0155] The patterned element can extend from the surface and have a height of less than 1,000 nanometers, preferably between 100 nanometers and 1,000 nanometers (e.g., 600 nanometers).

[0156] For example, an optical modulator can be configured for use within a defined spectral range (such as the visible light range). The patterned element can be transparent within the defined spectral range, for example, transparent to visible light. The visible light spectral range can be defined as 400 nm to 750 nm. The patterned element can be used to configure the spectral properties of the optical modulator.

[0157] The total transmittance of the patterned element within a defined spectral range may be higher than a threshold value, for example, at least 70%, or at least 80%. The total transmittance of the patterned element may be in the range [x-5, x+5], where x represents the total transmittance of the substrate.

[0158] Interestingly, the patterned elements do not need to be transparent. In one embodiment, the total transmittance of the patterned elements across the spectral range is at most 10%.

[0159] The spectral range may include infrared light, for example, infrared light with wavelengths between 750 nm and 1000 nm or 1500 nm. The spectral range may also include visible light and infrared light, for example, visible light and infrared light with wavelengths between 400 nm and 1000 nm or 1500 nm.

[0160] Patterned elements are placed in the path of light passing through the substrate and optical layer. Since the patterned elements optically influence the light, they affect the optical properties of the light modulator. Therefore, by configuring the shape and / or pattern of the patterned elements, the optical properties of the light modulator can be modified. For example, the patterned elements can alter the wavefront of light reflected from or transmitted through the substrate.

[0161] [picture] [6b] A schematic illustration shows one example of an embodiment of a transparent substrate 602 used in an optical modulator. The view in FIG. 6b is from top. Patterned elements are visible in FIG. 6b; one of the patterned elements has element symbol 622. FIG. 6b is too large to show; element symbol 632 represents a virtual scale of 1 micrometer. The patterned elements shown can be represented by transparent cylinders. A top circular view of the cylindrical pattern is visible in FIG. 6b. The pattern shown in FIG. 6b is a detail; in one embodiment, the pattern extends across the substrate. Further details about the cylindrical pattern can be found in the paper "Flat optics with dispersion-engineered Metasurfaces" by Wei Ting Chen et al., which is incorporated herein by reference. Table 1 of the latter paper also shows various materials suitable for metasurfaces and information on their size and bandwidth.

[0162] Instead of cylinders, patterned elements can have a variety of other shapes. For example, the top view of a patterned element can be V-shaped, as shown in the paper "Broadband Light Bending with Plasmonic Nanoantennas" by Xingjie Ni et al., which is incorporated herein by reference. This paper also explains a generalized version of Snell's law that allows for better control of light manipulation. Such metasurfaces can be designed where the theoretical predictions given by the generalized Snell's law match experimental data very well.

[0163] Various CMOS fabrication techniques can be used to fabricate metasurfaces. The paper "Large-area metasurface on CMOS-compatible fabrication platform: driving flat optics from lab to fab" by Nanxi Li et al. is included here by reference. This paper discusses low-cost, large-area metasurfaces that can be mass-produced using common semiconductor techniques (e.g., using lithography steppers and scanners).

[0164] One example of a method for fabricating metasurfaces is given in the paper "High efficiency dielectric metasurfaces at visible wavelengths" by Robert C. Devlin et al., which is incorporated herein by reference. For example, Figure 2 of that paper illustrates the fabrication process of a dielectric metasurface.

[0165] [picture] [6c.1] Schematic illustration of one example of an embodiment of a transparent substrate used in an optical modulator. [picture] [6c.2] An example of one embodiment of a transparent substrate used in an optical modulator is schematically shown. FIG. 6c.1 shows a side view. FIG. 6c.2 shows a top view of the same configuration shown in FIG. 6c.1. The figures show a substrate having both of its patterned elements.

[0166] The patterned element has a 2D diameter, which is defined as the maximum diameter in a two-dimensional cross-section of the substrate parallel to the nano-element. For example, the 2D diameter is the maximum distance between any two points of the patterned element, where the two points are restricted to being located in the same plane parallel to the substrate. The 2D diameter is indicated in these figures using element symbol 662.

[0167] The patterned element has a height defined as the maximum extension of the patterned element from the substrate as measured in a direction perpendicular to the substrate. The height of two patterned elements is indicated by element symbol 661. Furthermore, the distance to the next nearest element is indicated by element symbol 663.

[0168] In one embodiment, the 2D diameter, height, and closest distance are related to the target frequency of the patterned element.

[0169] For example, in one embodiment, the 2D diameter is at most 10 micrometers, at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers.

[0170] For example, in one embodiment, the minimum distance between two patterned elements is at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers. For example, in one embodiment, the minimum distance between two patterned elements is at least 10 nanometers, at least 50 nanometers, at least 100 nanometers, 200 nanometers, or 400 nanometers.

[0171] If another dimension of the patterned element is smaller, the patterned element is allowed to have a longer dimension. For example, in one embodiment, the patterned element has at least two discontinuous edges, and the minimum distance between two points on each of these discontinuous edges is at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers. For example, the patterned element can be polygonal, such as a rectangle. The rectangle can have short edges, for example, below the indicated range, while the other edges can be longer, for example, longer than 2 micrometers.

[0172] For example, in one embodiment, the patterned element extends along at least two directions. These two directions may form angles between 30 and 150 degrees, between 60 and 120 degrees, or, for example, approximately 90 degrees. For each direction, the longest distance can be identified, for example, the longest distance between two points within the same patterned element. In one embodiment, the shorter of the two distances is at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers. For example, the nano-element may be an ellipse with a length greater than its width.

[0173] In one embodiment, the size of the patterned elements or the distances between them may vary. For example, in one embodiment, different positions of the light modulator may yield different optical effects. For instance, in a signboard, a holographic effect may be desired in one portion of the light modulator, but not in all portions. Therefore, small and large patterned elements, small or large distances between objects may be mixed within the light modulator.

[0174] For example, in one embodiment, the height is at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers, preferably between 100 nanometers and 1000 nanometers.

[0175] In one embodiment, the 2D diameter, height, and closest distance are all at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers.

[0176] The height of patterned elements can be uniform; for example, a patterned element can have a flat top parallel to the substrate. The patterned element on the left in Figure 6c.1 has a uniform height. Across the substrate, the height of patterned elements can also be uniform; for example, all patterned elements have the same height. The two patterned elements in Figure 6c.1 have the same height.

[0177] Typically, the height of the patterned element is much smaller than the height (e.g., thickness) of the substrate, although the patterned element can also be applied to a thin substrate. For example, in one embodiment, the substrate has a thickness of 10 micrometers or more, while the patterned element has a height of, for example, less than one micrometer. For example, the substrate can be a plastic film. The thickness of the substrate can be at least 10 times the height of the patterned element. However, this ratio is usually higher. For example, in one embodiment, the thickness of the substrate can be at least 100 times or at least 1000 times the height of the patterned element.

[0178] Figures 6d.1 and 6d.2 illustrate the function of the super-surface in the context of the optical modulator.

[0179] [picture] [6d.1] Schematic illustration of an example of an optical modulator 643 without patterned elements.

[0180] A main wavefront 642 is shown projected onto a light modulator. For example, the light modulator may be smart glass, and the main wavefront 642 may be derived from ambient light (e.g., sunlight). A light modulator 643, schematically indicated only, may be of the type shown in Figures 4a-4c and 5a-5b, but without patterned elements forming a metasurface on the light modulator. A cross-section of drive electrodes arranged in a pattern spanning across substrates is shown in the light modulator 643; in this case, the electrodes are disposed on two substrates.

[0181] After the wavefront passes through the optical modulator 643, the electrode pattern has a distorting effect on the wavefront. The distorted wavefront 644 is shown in Figure 6d.1. This distortion is visible in optical artifacts such as rainbow effects and diffraction. This distortion can also be calculated (e.g., using the generalized Snell's law).

[0182] [picture] [6d.2] Schematic illustration of one embodiment of a light modulator 653 having patterned elements. Except that the light modulator of FIG. 6d.2 includes patterned elements forming a metasurface according to an embodiment, this light modulator is similar to the light modulator of FIG. 6d.1.

[0183] A main wavefront 642 is shown projected onto an optical modulator. The optical modulator 653 uses the same drive electrodes as in FIG. 6d.1, but includes patterned elements extending across the substrate for forming a metasurface on the optical modulator. A patterned element is shown using element symbol 655. In this example, the patterned elements are applied on one side of each substrate, in this case, on the side facing the optical layer of the optical modulator 653. As shown herein, alternatively or additionally, the metasurface may be formed on a surface opposite to the optical layer; the metasurface may be formed on only one substrate, or on more than two substrates.

[0184] In addition to the influence of the driving electrode on the wavefront, the nanopatterned element also has an effect on the wavefront. This element can be selected to correct the wavefront; Figure 6d.2 shows the corrected wavefront 654.

[0185] The patterned elements are selected using a computerized selection algorithm. This algorithm calculates the effect of the combination of driving electrodes and patterned elements on the main wavefront 642. The position and / or shape of the patterned elements are modified in multiple iterations to minimize the loss function, which includes one or more loss terms.

[0186] The loss term used in this case includes the distance term between the outgoing wavefront and the regular main incoming wavefront. That is, minimizing any optical variations in the wavefront. For example, minimization can be applied to a specific light frequency or multiple frequencies, such as the frequency of visible sunlight. For example, minimization can be applied to various angles of light. The severity of optical artifacts can depend on the properties of the light, such as its direction and frequency. By performing simulations under a range of conditions, a generally effective design can be selected.

[0187] Therefore, multiple candidate designs can be simulated for a range of conditions (e.g., different lighting conditions). From these candidate designs, one design is selected, for example, the design with the lowest average loss under these conditions.

[0188] The loss term can be used, either alternatively or as a means, to directly assess the severity of known artifacts (e.g., rainbow effects and diffraction). Minimizing this loss term allows the light modulator to influence the light while reducing distracting elements. Optimization can be achieved using hill-climbing techniques, such as simulated annealing.

[0189] To reduce computation time, in one embodiment, the pattern of the patterned elements forming the metasurface can be optimized for smaller areas (e.g., construction blocks) that can be repeated on the substrate.

[0190] To reduce computation time, in one embodiment, the patterned elements are selected from a predetermined set, for example, using a finite number of cylindrical or V-shaped elements of various sizes. Optimizing the metasurface can then be simplified to selecting from a finite number of elements of various sizes and positions. Therefore, optimization does not need to consider all possible size ranges. Computation time can be further reduced by constraining the position of the elements to a predetermined grid. Computation time can be further reduced by constraining the possible rotations of the elements to a finite number of predetermined sizes. The latter optimization is not suitable for rotationally symmetric elements (e.g., cylinders), but can be used for polygonal shapes (e.g., V-shaped elements).

[0191] Optimization can also be performed on the positions of the electrodes and patterned elements. In this case, the loss term may also include electrode-specific losses, such as the operation of the optical modulator, for example, the speed and uniformity of state transitions.

[0192] In Figure 6d.2, optimization aims to reduce the influence of the electrodes on the wavefront. However, this is not mandatory; alternatively, optimization can be intended to introduce any desired changes to the wavefront. For example, in one embodiment, patterned elements are configured to alter the wavefront 642 of light passing through the substrate to generate a holographic image.

[0193] Patterned elements (e.g., subwavelength-scale geometries) can be customized to produce a wide range of optical functions. For example, to generate a metasurface design, the patterned elements can be patterned to optimize the topology of the desired optical response, for example, using a free-form metasurface. For instance, topology optimization can use a local gradient-based optimizer, for example, using an adjoint variable method. A local gradient-based topology optimizer takes an initial device design and iteratively refines it through perturbations (e.g., small changes to the geometry of the metasurface and / or patterned elements) to approximate the desired optical response. Advantageously, the adjoint variable method can be used to obtain the perturbations. This method allows for the formation of advanced metasurfaces with the ability to surpass existing design methods.

[0194] For example, gradient-based optimization can use the adjoint variable method. In this method, a set of adjoint variables is introduced and used to calculate the gradient of the objective function with respect to the design variables. This gradient information is then used to make small adjustments to the design to improve system performance. The objective function may include distortion parameters, such as diffraction and rainbow, uniformity, and possible target grayscale. Optimization can be combined with one or more particle distributions (such as those generated using driving electrodes, as shown in Figures 5a to 5c).

[0195] Topology optimization is further discussed in J. Fan’s “Metagrating Topology Optimization”, which is incorporated herein by reference.

[0196] Patterned elements (e.g., metasurfaces) can be used for various purposes. One important application is to correct the optical effects of electrodes. Like patterned elements, driving electrodes affect the optical effects of optical modulators. Compared to the optical effects formed by the driving electrodes of the modulator, patterned elements can create the opposite optical effects, for example, compensating for optical aberrations generated by the driving electrodes. For example, a common problem with substrates of the type shown in Figure 6a is diffraction, sometimes called the rainbow effect. Patterned elements can counteract the diffraction caused by the electrodes. The patterns shown in Figures 2a to 2f undergo different degrees of diffraction. For example, in this respect, pattern 2f has better properties compared to the pattern in Figure 2b. Nevertheless, in both cases, adding patterned elements helps reduce the rainbow effect.

[0197] Patterned elements can be configured to compensate for various optical artifacts in an optical modulator. Optical artifacts can be one or more of the following groups: diffraction, refraction, scattering, and disturbance of light as it passes through or is reflected from the substrate. The diffraction effect caused by the drive electrodes can be reduced by arranging patterned elements to form equal but opposite distortions.

[0198] In one embodiment, the patterned elements are configured to reduce (e.g., minimize) light reflection. In this way, due to the reduced reflection, the opaque state of the light modulator is perceived as a deeper black.

[0199] In one embodiment, patterned elements are configured to focus incident light within the optical layer of the light modulator. This reduces artifacts. For example, in a light modulator including a first substrate, an optical layer, and a second substrate, patterned elements on the first and / or second substrates may be configured to focus incident light (e.g., light incident from outside the light modulator onto the first and / or second substrates) within the optical layer.

[0200] Patterned elements can provide wavelength control to filter light passing through a substrate according to wavelength. The optical effects provided by patterned elements can vary for different wavelengths of light. Patterned elements can provide polarization control to manipulate linear or circular polarization. For example, polarization can be influenced by patterned elements with non-rotational symmetry; for instance, rectangular or non-square objects can affect polarization.

[0201] In one embodiment, the patterned elements are fixed. For example, these elements may be applied to a substrate in a predetermined shape by a fixed material. For example, these elements are passive. However, this is not mandatory. In one embodiment, the patterned elements introduce optical distortions that depend on external factors such as temperature, pressure, and / or electric fields. For example, the patterned elements may include a phase-changing material. For example, the patterned elements have a controllable shape. For example, patent application US2021333575A1 (incorporated by reference) discloses reversible phase-changing materials suitable for incorporation into a superlens.

[0202] For example, in one embodiment, the nano-element can preferably be electrically controlled independently of the electrodes, and / or can be controlled by temperature. Preferably, the nano-element can be controlled independently.

[0203] In one embodiment of the optical modulator, there is an interaction between the temperature of the optical modulator and the phase transition of the metasurface caused by the temperature.

[0204] The temperature in an optical modulator can be changed by various components (e.g., heating elements, such as heating wires, micro-heating elements). Goran Miskovic’s paper “Modeling and fabrication of Pt micro-heaters built on alumina Substrate” illustrates micro-heating elements on a glass-coated substrate; this paper is incorporated herein by reference.

[0205] By changing the shape of the patterned element, the way an optical modulator modulates the wavefront can be controlled. For example, in the operation of an optical modulator, a patterned element with a variable shape can be configured in different shapes. For example, this allows for changes in the phase, amplitude, and / or polarization of light interacting with the substrate. For example, in one embodiment, the patterned element includes a phase-changing material having optical distortion that depends on external factors such as temperature, pressure, and / or electric field.

[0206] [picture] [6e.1] Schematic illustration of an example of an optical modulator with conductive patterned elements in an inactive state. Figure [6e.2] Schematic illustration of an example of an optical modulator in which conductive patterned elements are in operation. The substrate of these figures can be used as one of the substrates in an optical modulator (e.g., an electrophoretic optical modulator of the type shown in any of Figures 3a to 5b).

[0207] Patterned elements are applied to a substrate, shown here in a top plan view. The patterned elements are shown as rectangles. The patterned elements are transparent, for example, transparent to visible light, or transparent in the target spectrum. Therefore, the patterned elements have reduced optical effects; for example, these patterned elements can form a metasurface, but the effect can be relatively small. Specifically, the patterned elements can be configured to have a refractive index close to that of the substrate to further reduce optical effects.

[0208] In one embodiment, a substrate (e.g., a first substrate) is used in an optical modulator configured such that particles can be aligned with patterned elements. This can be achieved by placing electrodes close to the patterned elements or by placing drive electrodes below the patterned elements, but a particularly advantageous way to achieve this is by using conductive patterned elements. The conductive patterned elements can be provided with a potential, for example, by using electrophoretic forces to allow particles to move toward the conductive patterned elements. For example, a second substrate may have conductive patterned elements aligned with elements on the first substrate. For example, the elements on the second substrate may be arranged in a pattern that is mirrored relative to the pattern in the first substrate.

[0209] By applying a potential to a conductive patterned element, charged particles are aligned with the conductive patterned element. This effect is shown in Figure 6e.2. Although the previous patterned element was transparent and had a small optical modulation effect, the transparency is reduced and the optical effect of the patterned element is increased by the aligned particles. In this way, a metasurface is formed, and its effect can be increased or decreased as desired.

[0210] The conductive patterned element can be electrically controlled to modulate light using the same driving electrodes used in an optical modulator. Alternatively, the conductive patterned element can be electrically controlled using driving electrodes specifically applied to the conductive patterned element.

[0211] Therefore, in one embodiment, the patterning element may be conductive and configured to modulate particles, such as light-absorbing particles, for example, particles that absorb light in a target spectrum (e.g., visible light). The optical properties of the patterning element are modulated. The patterning element may include ITO, for example, an ITO sheet.

[0212] In one embodiment, all or part of the patterned elements on the substrate are transparent and conductive patterned elements. For example, these patterned elements may be transparent depending on the absorption range targeted by the light modulator and / or the substrate. For example, the light modulator may be configured for use within a defined spectral range (such as visible light). The patterned elements may be transparent within the defined spectral range, for example, transparent to visible light.

[0213] Furthermore, the optical parameters of these patterned elements can be close to those of the substrate, especially the refractive index. For example, the refractive index of the patterned elements can be within 10% of the refractive index of the substrate.

[0214] Conductive patterned elements are configured to interact with particles in the optical layer of the optical modulator.

[0215] Patterned elements are configured to receive potentials to provide control over optical modulation in an optical modulator. For example, the patterned elements may be individually electrically addressable, e.g., in a column-row addressing scheme. A regular grid (e.g., a regular grid as part of a column-row addressing scheme) covering at least a portion of a first surface may be applied to the first surface. Column-row addressing may use separate electrodes, rather than drive electrodes. For example, the optical modulator may be pixelated, with the patterned elements and, where appropriate, the drive electrodes, both column- and row-addressed. This allows for localized adaptation of optical effects and, where appropriate, localized adaptation of transparency.

[0216] The optical modulator is configured to control its grayscale by modulating the position of particles in the optical layer. This can be achieved by applying a control signal (e.g., an electrical control signal) to electrodes on the substrate. For example, in one embodiment, each of the two substrates has at least two electrodes, allowing control over charged particles in the optical layer between the two substrates, thus obtaining a controllable grayscale. For example, the signal could be an AC signal.

[0217] In one embodiment, the optical effect of the patterned element can also be modulation in an optical modulator. For example, the patterned element can be modulated by changing, for example, the temperature of the pattern including the phase-changing material. For example, the patterned element can be conductive, allowing light-absorbing particles in the optical layer to accumulate near the patterned element.

[0218] The optical modulator can be configured to control the optical modulator by applying a first control signal to the drive electrode and a second control signal to the patterning element. In one embodiment, the second control signal to the patterning element depends on the desired gray level set within the modulator (e.g., set by the user).

[0219] For example, these signals can be obtained before the operation phase but during the calibration phase. For example, the light modulator may be mounted at its final destination, for example, in the form of a smart window. Sensors (e.g., cameras) can be configured to observe the effects of the light modulator. Sensor measurements can be used to modify the first and / or second control signals to reduce the occurrence of undesirable phenomena (e.g., diffraction, rainbows). For example, during the calibration phase, the light modulator can be driven within the range of the first and second control signals. Sensor measurements, for example, images, are recorded for various signals. Optical parameters are derived from these sensor measurements, specifically, the grayscale (e.g., transparency level) and distortion values ​​(e.g., observed diffraction and / or rainbow amount) of the light modulator.

[0220] In one embodiment, information about the direction of incident light (e.g., sunlight) can be obtained, for example, by a GPS sensor that is part of a satellite navigation device. This is particularly useful in automobiles (e.g., automobiles with smart glass). This information can be obtained dynamically during operation.

[0221] In one embodiment, information regarding glass orientation, such as during a calibration phase, can be obtained by applying a sensor to the glass. This sensor can be fixed, for example, as part of the smart glass package. However, it can also be temporary. Specifically, orientation information can be obtained by placing a smartphone flat on the glass. For example, the smartphone's application can forward the orientation information to the controller of the smart glass (e.g., a light modulator).

[0222] Directional information is useful because the control signals used for patterned elements can depend on the current angle of light.

[0223] Algorithms can be applied to sensor values ​​and calibration control signals, for example, to derive a model of an optical modulator from self-sensor measurements, which predicts the optical effects of the optical modulator and its current control signal. This model or algorithm can be computational (e.g., applying physical laws such as Snell's law), but is advantageously alternatively a machine learning model. For example, a neural network can be trained to predict the optical effects from control signals and possibly other sensor values—the optical modulator may be equipped with sensors such as temperature and light sensors. Based on sensor values ​​demonstrating the effect of a particular control signal, the algorithm learns which control signal to use to obtain a specific effect. After a calibration period, the camera can be removed. In one embodiment, the system can continue to learn and (e.g., using user feedback or sensor measurements) further optimize the model. Furthermore, relatively slow changes in the environment will be automatically taken into account. The optical modulator can be manufactured independently of the environment in which it is ultimately installed and operated, while still achieving fine optical control. Control of the metasurface can depend on the angle and intensity of the incident light.

[0224] Therefore, the first and second control signals can be stored and / or exported when needed. Appropriate control signals can be exported depending on the current sensor values ​​(e.g., current temperature and / or current light level or angle).

[0225] One embodiment of a method for calibrating an optical modulator includes: - Provide light modulators, for example, install light modulators. Light modulators can be installed in fixed locations, such as as smart glass in buildings (e.g., offices). Light modulators can also be installed in non-fixed locations, such as as smart glass in vehicles (e.g., cars). - Information about the distortion and / or transparency of the light modulator is obtained from an image sensor that observes the light modulator. For example, the image sensor may be a temporary image sensor installed to obtain information about the optical effects of the light modulator. For example, the image sensor may be a camera placed in front of the light modulator during the calibration phase. For example, the camera may be mounted on a tripod. For example, the image sensor may be placed inside the interior of a building with glass. For example, the image sensor may be placed inside a vehicle with glass. If the light modulator is not fixed, orientation information may be recorded simultaneously during the calibration phase, for example, by moving the light modulator or a portion thereof while driving a vehicle in which the light modulator is mounted. - Export the control signals used to control the optical modulator during the operation phase.

[0226] During the calibration phase, multiple control signals can be applied to the driving electrodes and / or the patterning elements. The image sensor can observe the effects. These effects can be summarized by distortion values ​​and transparency values ​​(e.g., grayscale values). Control signals that provide the desired effect (e.g., specific transparency and low distortion) can be stored. For example, new control signals can be derived from stored control signals by interpolation. A machine-learnable model can be trained to predict the effects of the optical modulator based on the control signals. A favorable control signal can be derived by trying multiple control signals in the trained model, for example, selecting a control signal with the desired parameters.

[0227] In one embodiment, the calibration method further includes obtaining information about the orientation of the light modulator from an orientation sensor applied to the light modulator. For example, the orientation sensor may be shared with a GPS device (e.g., a satellite navigation device or a smartphone). The orientation sensor may also be independent. The orientation sensor may be temporary, for example, applied only during the calibration phase. In one embodiment, the light modulator includes the orientation sensor.

[0228] Orientation sensors and image sensors can be configured to provide sensor data, such as measurements, for example, information about images and / or orientation, to the controller of the light modulator.

[0229] Following the calibration phase, the light modulator can be controlled. Methods for controlling the light modulator may include applying a potential to the driving electrodes to modulate the electromagnetic field in the optical layer, thereby providing electrophoretic and / or dielectrophoretic movement of particles in the optical layer, resulting in modulation of light passing through the substrate. For example, the control signal applied to the driving electrodes may be a control signal stored during the calibration phase. Patterned elements applied to the surface of the light modulator can alter the phase, amplitude, and / or polarization of light passing through the substrate.

[0230] The patterned element may be passive, for example, not configured to receive control signals. In one embodiment, the patterned element is active, for example, configured to receive control signals to modulate its optical effects. For example, the patterned element may include a phase-changing material having optical distortion dependent on external factors such as temperature, pressure, and / or electric fields, the method including modulating the external factors to modulate the optical distortion. The patterned element may be conductive and configured to modulate its optical effects through particles selectively disposed on top of the patterned element. The control method may include modulating external factors (e.g., applying a control signal) to modulate the optical distortion. The control signal may be stored in or derived from a calibration phase.

[0231] Patterned elements can be combined with coatings and applied to various surfaces of the substrate to provide various advantages. Figures 7a through 7g all show substrates used in optical modulators. The substrates in these figures assume ambient light is above the image and the optical layer is below the substrate. Only in Figure 7a is the side configured to be oriented towards the optical layer schematically indicated by element symbol 712, but Figures 7b through 7g are oriented in the same manner. The bottom substrate can be obtained from any of Figures 7a through 7g by mirroring the substrate in the horizontal axis.

[0232] [picture] [7a] This figure schematically illustrates one example of an embodiment of a transparent substrate used in an optical modulator. The figure shows a transparent substrate 711.

[0233] The substrate 711 has two surfaces; the first surface is configured to be oriented toward the optical layer of the light modulator; this side of the substrate is indicated by element symbol 712.

[0234] Starting from substrate 711, a layer having patterned elements is applied to a first surface of substrate 711. A patterned element is indicated by element symbol 745. The patterned element is configured to modify the phase, amplitude, and / or polarization of light interacting with the substrate. Light interacting with the substrate includes light passing through the surface and / or light reflected from the surface. For example, the patterned element may be configured to form a metasurface.

[0235] In this example, the patterned element is coated in a coating 751 for the patterned element. Typically, coatings used in optical modulators are transparent. The protective coating 751 prevents damage to the nano-element.

[0236] The substrate 711 has at least one driving electrode applied thereto on its first surface. One electrode is labeled 721. The electrodes shown may all be formed as a single connected electrode portion. In a preferred electrophoretic optical modulator, at least two interleaved electrodes are applied. The electrodes can be used to modulate the optical properties of the optical modulator.

[0237] In this example, a coating with patterned elements is applied starting from the substrate, followed by the application of a pattern for the driving electrodes. In this example, no coating is applied to the electrodes. In this configuration, the electrodes are in fluid contact with the optical layer. In this configuration, the patterning of the nano-elements and electrodes can be determined independently of their respective positions.

[0238] [picture] [7b] This schematically illustrates one example of an embodiment of a transparent substrate used in an optical modulator. The substrate is similar to that of FIG. 7a, except that a coating 752 for driving electrodes has been applied in this example. In this configuration, the electrodes are not in direct fluid contact with the optical layer. Typically, both coatings 751 and 752 are non-conductive and transparent.

[0239] The protective coating 752 prevents contaminants (such as particles, fibers, stones, blocks, grains, etc.) present in the optical layer from directly contacting the electrodes. These contaminants can form in various ways (e.g., through the aggregation of smaller particles, static electricity, trapping between electrodes, etc.). These contaminants can cause short circuits between electrodes on opposing substrates, between adjacent electrodes on the same substrate, and can damage the electrodes themselves or any combination of electrodes. In one embodiment, the protective coating prevents both physical damage to the electrodes and short circuits between the electrodes.

[0240] [picture] [7c] Schematic illustration of one example of an embodiment of a transparent substrate for use in an optical modulator. The substrate is similar to that of FIG. 7a, except that in this example both the nano-elements and electrodes are applied to the substrate in the same layer. For example, this configuration is thinner compared to FIG. 7b. The location of the nano-elements is now selected based on the electrodes; for example, the nano-elements cannot be positioned where electrodes are located. A combined coating 753 for driving electrodes and patterning element coatings is applied to both the nano-elements and electrodes.

[0241] [picture] [7d] This schematically illustrates one example of an embodiment of a transparent substrate used in an optical modulator. In this example, nano-elements and electrodes are applied to opposite surfaces of substrate 711. Nano-elements are applied to a second surface of substrate 711, facing away from the optical layer. Electrodes are applied to a first surface of substrate 711, facing the optical layer.

[0242] In this example, a coating 751 is applied for patterning elements, but no coating is applied to the electrodes.

[0243] [picture] [7e] Schematic illustration of one example of an embodiment of a transparent substrate used in an optical modulator. This substrate is similar to that of FIG. 7d, except that a coating 752 for driving electrodes is also applied to the first surface.

[0244] [picture] [7f] This schematically illustrates one example of an embodiment of a transparent substrate used in an optical modulator. In this example, patterned elements are applied to both surfaces of the substrate. Figure 7f sequentially shows a first layer of nano-elements, substrate 711, a second layer of nano-elements in coating 751, and a driving electrode in coating 752. In one embodiment, coating 751 is also applied to the second surface of the substrate.

[0245] [picture] [7g] Schematic illustration of one example of an embodiment of a transparent substrate used in an optical modulator. FIG7g is similar to FIG7f except that the coating is not applied to the electrodes. Coating 751 may additionally be applied to a second surface, for example, to protect nano-elements.

[0246] In some embodiments, the protective coating (e.g., coatings 751, 752, and / or 753) provides additional optical functionality to the device. In some embodiments, this functionality is a standalone optical function. In some embodiments, this functionality is an optical function that works in conjunction with the electro-optical effects of the device. For example, such electro-optical effects may be reflection, anti-reflection, diffraction, and / or diffraction effects for all wavelengths of light or for a portion of the electromagnetic spectrum (such as UV, visible, and / or IR). The protective coating material may be selected to have a refractive index sufficiently different from that of the fluid solvent to generate significant light refraction. For example, a protective coating made of silicon nitride with an optical refractive index of 3 may be combined with a fluid solvent with an optical refractive index less than 2. The difference in refractive index will induce the refraction of incoming light, resulting in a change in the direction of light following Snell's law. The light modulator can then direct the incoming light to a designed specific direction. This effect may be combined with a specific shape and morphology of a patterned protective coating to refract light in multiple directions and thus increase light diffusion or turbidity. Similarly, different protective coatings from the same substrate or from different substrates can enhance a specific light path or diffusion.

[0247] See PCT / EP2022 / 066713 of the same applicant for more information on coatings, for example, used to protect electrodes; however, similar coatings can be applied to nano-devices.

[0248] Depending on the materials or combinations of materials chosen, 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 coating, dip coating, spray coating, inkjet printing, slot coating, and combinations thereof) can be used to apply protective coatings.

[0249] [picture] [8a] Schematic illustration of one example of an embodiment of a method 810 for manufacturing a substrate as described in one embodiment. Method 810 includes: - Provide 811 substrate - Applying a driving electrode 812 to the first surface of the substrate to configure the substrate of the light modulator. - A patterning element is applied to the surface of a substrate by means of patterning element 813, thereby configuring the substrate to have a super-surface; the surface on which the patterning element is applied may be a first surface of the substrate or a second surface opposite to the first surface. Applications 812 and 813 may be performed simultaneously. The application of the patterning element (813) may be performed before the application of (812).

[0250] [picture] [8b] This schematically illustrates one example of an embodiment of a method 820 for manufacturing an optical modulator as described in one embodiment. Method 820 includes: - Provided 821 a first substrate and a second substrate according to an embodiment (e.g., according to method 810). The second substrate may or may not have electrodes and / or patterned elements applied to the electrodes. - An 822 optical layer is applied between the first substrate and the second substrate. - Seal the sides of the first substrate and the second substrate of 823.

[0251] [picture] [8c] This schematically illustrates one example of an embodiment of a method 830 for operating an optical modulator as described in one embodiment. Method 830 includes: - Applying a potential of 831 to the driving electrode modulates the electromagnetic field in the optical layer, thereby enabling electrophoretic and / or dielectrophoretic movement of particles in the optical layer, which in turn modulates the light passing through the substrate. - The phase, amplitude, and / or polarization of light passing through the substrate are altered by patterned elements applied to the surface of the substrate.

[0252] Where appropriate, the patterned element may include a phase-changing material having optical distortion that depends on external factors such as temperature, pressure, and / or electric field. Where appropriate, method 830 may further include modulating the external factors to modulate the optical distortion.

[0253] The following list of numbered clauses is an example, and each clause has been considered. These clauses are examples of embodiments.

[0254] [Substrate] [ ] Clause 1. A transparent substrate for use in an optical modulator, the substrate comprising: - At least one driving electrode (111-114, 121-124) is applied to a first surface of the substrate, the driving electrode is configured across the substrate in a pattern, the electrode is configured to receive a potential, thereby causing the optical properties of the light modulator to be modulated, wherein micron and / or nano-patterned elements are applied to the surface of the substrate, thereby changing the phase, amplitude and / or polarization of light interacting with the substrate.

[0255] Clause 2. As in Clause 1, wherein - The patterned elements have a maximum diameter in a two-dimensional cross-section parallel to the substrate of the nano-elements, the diameter being at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers, and / or - The minimum distance between two patterned elements is at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers, and / or - The minimum distance between two patterned elements is at least 100 nanometers, 200 nanometers, or 400 nanometers.

[0256] Clause 3. The substrate as described in Clause 1 or 2, wherein the patterned elements form a metasurface.

[0257] Clause 3.1. The substrate as described in any of the preceding clauses, wherein the patterned elements on the substrate have a plurality of different sizes, different shapes and / or different materials.

[0258] Clause 4. The substrate of any of the preceding clauses, wherein the patterned elements extend from the surface and have a height of less than 1,000 nanometers, preferably between 100 nanometers and 1,000 nanometers.

[0259] Clause 5. The substrate as described in any of the preceding clauses, wherein the patterned elements are applied to the first surface, and / or wherein the patterned elements are applied to a second surface opposite to the first surface.

[0260] Clause 6. The substrate as described in any of the preceding clauses, wherein the patterned elements are configured to compensate for the optical artifacts of the light modulator.

[0261] Clause 7. The substrate of Clause 6, wherein the optical artifact is any of the following: diffraction, refraction, scattering, or disturbance of light when passing through or reflected from the substrate.

[0262] Clause 8. The substrate as described in any of the preceding clauses, wherein the patterned elements are configured to form a diffraction effect opposite to that formed by the driving electrodes of the modulator.

[0263] Clause 9. The substrate as described in any of the preceding clauses, wherein the patterned elements provide wavelength control to filter light passing through the substrate according to the wavelength.

[0264] Clause 10. A substrate as described in any of the preceding clauses, wherein the patterned elements alter the wavefront of light passing through the substrate to generate a holographic image.

[0265] Clause 11. The substrate as described in any of the preceding clauses, wherein the patterned elements alter the wavefront of light reflected through the substrate and compensate for optical aberrations generated by the driving electrodes.

[0266] Clause 12. The substrate as described in any of the preceding clauses, wherein the patterned elements provide optical polarization control to manipulate linear or circular polarization.

[0267] Clause 12.1 The substrate as described in any of the preceding clauses, wherein the patterned elements are passive (e.g., not controllable by external factors) or active (e.g., controllable by external factors).

[0268] Clause 13. A substrate as described in any of the preceding clauses, wherein the patterned elements include elements with controllable shapes, the elements being configured to provide control over the changes in the phase, amplitude and / or polarization of light interacting with the substrate.

[0269] Clause 14. The substrate of any of the preceding clauses, wherein the light modulator is configured for use in a defined spectral range, wherein the total transmittance of the patterned elements in the spectral range is at most 10%.

[0270] Clause 15. The substrate as described in any of the preceding clauses, wherein the patterned elements include a phase-changing material having optical distortion dependent on external factors such as temperature, pressure and / or electric field.

[0271] Clause 16. A substrate for use in an optical modulator as described in any of Clauses 1 to 15, wherein the driving electrode across the pattern of the substrate comprises a plurality of repeating construction blocks.

[0272] Clause 15. The substrate as described in any of the preceding clauses, wherein - A construction block is repeated across the substrate in at least two directions, and / or - Multiple different building blocks are repeated across the substrate in one or two directions.

[0273] Clause 16. The substrate as described in any of the preceding clauses, wherein at least one drive bus is disposed on the substrate for each of the at least one drive electrode to drive the drive electrode, wherein... - For each driving electrode, at least one driving bus is disposed on one side of the substrate to drive the driving electrode, and / or - These drive buses are configured only on this side of the substrate, and / or - These drive buses are configured between the building blocks covering the substrate.

[0274] Clause 17. The substrate as described in any of the preceding clauses, wherein the substrate is non-rectangular.

[0275] Clause 18. A substrate for use in an optical modulator as described in any of the preceding clauses, wherein the at least one driving electrode comprises a plurality of driving electrodes. - The plurality of driving electrodes (111-114, 121-124) are staggered, each of the plurality of driving electrodes is arranged in a pattern across the substrate, the plurality of staggered driving electrodes are arranged alternately relative to each other on the substrate, and the pattern of the plurality of driving electrodes across the substrate includes a plurality of repeating construction blocks.

[0276] Clause 19. As in Clause 18, a substrate used in an optical modulator, wherein the building block includes - The plurality of interleaved electrodes extend across the building block in at least two directions, the interleaved electrodes in the building block forming the driving electrodes, and the maximum length between any two points on the electrode along the electrode on the building block for at least one of the plurality of interleaved electrodes in the building block is at least twice the length of the diagonal of the building block unit.

[0277] Clause 20. A substrate for use in an optical modulator as described in any of the preceding clauses, wherein the at least one driving electrode comprises a plurality of driving electrodes, wherein - The nearest distance from any point on the substrate to the first driving electrode and to the second driving electrode is less than the threshold value, and / or - The sum of the nearest distances from any point on the substrate to the first driving electrode and to the second driving electrode is less than a first threshold value and / or less than a second threshold value, and / or - The distance from a point on the first driving electrode to a point on the second driving electrode is at least a second threshold value, and / or - The horizontal and / or vertical size of the constructed block is at least 10 times the sum of the electrode line width and the electrode distance.

[0278] [Optical modulator] [ ] Clause 21. An optical modulator comprising a first substrate and a second substrate as described in any one of Clauses 1 to 20, an optical layer extending between the first substrate and the second substrate, wherein the optical properties of the optical modulator can be modified at least by applying a potential to the driving electrode.

[0279] Clause 22. An optical modulator comprising: - A first substrate and a second substrate, at least one of which (e.g., according to one embodiment, or according to clauses 1 to 20) is provided with patterned elements, at least one of which is configured with its inner sides facing each other, the first substrate being transparent, and at least one driving electrode being applied to the inner side of the first substrate, the driving electrode extending in a pattern across the inner side of the first substrate. - An optical layer comprising a fluid having particles, disposed between the first substrate and the second substrate. - A controller configured to apply a potential to the at least one drive electrode to obtain an electromagnetic field, thereby providing movement of the particles toward or away from the drive electrode, thereby modulating the optical properties of the optical modulator.

[0280] Clause 23. An optical modulator as described in any of the preceding clauses, wherein at least one drive electrode comprises an ITO electrode.

[0281] Clause 24. An optical modulator as described in any of the preceding clauses, wherein the particles are charged or rechargeable, and the controller is configured to apply a potential to the drive electrode to obtain an electromagnetic field, thereby providing electrophoretic movement of the particles toward or away from the drive electrode, thereby causing the optical properties of the optical modulator to be modulated.

[0282] Clause 24.1. An optical modulator as described in any of Clauses 21 to 24, wherein a plurality of interleaved drive electrodes are arranged across the inner side of each of the first substrate and the second substrate, and a controller is configured to apply electrical signals to the plurality of electrodes to obtain an electric field between the plurality of electrodes, thereby providing electrophoretic movement of the particles, thereby causing the optical properties of the optical modulator to be modulated.

[0283] Clause 24.2 The optical modulator as described in any of Clauses 21 to 24.1, wherein the optical modulator is configured to... - The non-transparent state is switched by forming an alternating voltage on at least one of the first substrate and the second substrate, and by applying an alternating current between at least the first electrode and the second electrode on the first substrate and / or between the first electrode and the second electrode on the second substrate. - The transparent state is switched by forming an alternating voltage between the first substrate and the second substrate, applying an alternating current between the first electrode on the first substrate and the first electrode on the second substrate, and / or between the second electrode on the first substrate and the second electrode on the second substrate.

[0284] Clause 24.3 The optical modulator as described in Clauses 21 to 24.2, wherein the electrical signal is an AC signal.

[0285] Clause 24.4 An optical modulator as described in any of the preceding clauses, wherein the particles are charged or rechargeable, and wherein the particles move due to electrophoretic forces.

[0286] Clause 25. An optical modulator as described in any of the preceding clauses, wherein the particles are charged or rechargeable, and wherein the particles move due to electrophoretic forces.

[0287] Clause 26. An optical modulator as described in any of the preceding clauses, wherein the driving electrode is a linear electrode, for example, wherein the linear electrode extends along a longitudinal direction and along a transverse direction, and at least in a local portion of the linear electrode, the extension along the longitudinal direction is at least 10 times longer, and more preferably at least 100 times longer, than the extension along the transverse direction.

[0288] Clause 27. The optical modulator as described in any of the preceding clauses has - Transparent and opaque states, and / or - Reflective and non-reflective states The optical modulator is configured to switch between states by modulating the current applied between one or more driving electrodes on the first substrate and, as appropriate, between one or more driving electrodes on the second substrate.

[0289] Clause 28. The optical modulator as described in any of the preceding clauses, wherein - An electrical signal is provided in one or more electrodes using alternating current (AC), or - An electrical signal is provided in one or more electrodes with a direct current (DC), wherein the voltage is periodically reversed.

[0290] Clause 29. An optical modulator as described in any of the preceding clauses, wherein the first substrate and the second substrate are transparent.

[0291] Clause 30. An optical modulator as described in any of the preceding clauses, wherein one of the first substrate and the second substrate is transparent and one of the first substrate and the second substrate is reflective or partially reflective.

[0292] Clause 31. An optical modulator as described in any of the preceding clauses, wherein the one or more electrodes comprise a plurality of interleaved mesh electrodes. - Multiple interlaced mesh electrodes extend in a two-dimensional pattern across the first substrate and across the second substrate, and two mesh electrodes on the substrate intersect at multiple intersection points distributed on the substrate.

[0293] Clause 32. The optical modulator as described in any of the preceding clauses, wherein - These particles are nanoparticles and / or microparticles, and / or These particles are adapted to absorb light. These particles are pigment particles.

[0294] Clause 33. An optical modulator as described in any of the preceding clauses, wherein the at least two electrodes comprise a conductive material with a resistivity of less than 100 nΩm at 273 K.

[0295] Clause 34. An optical modulator as described in any of the preceding clauses, wherein the electrodes are in contact with the fluid or wherein the electrodes (e.g., by means of a coating) are separated from the fluid.

[0296] Clause 35. An optical modulator as described in any of the preceding clauses, wherein the electrodes applied to the substrate cover 1% to 30% of the substrate surface.

[0297] Clause 36. The optical modulator as described in any of the preceding clauses, wherein the potential operates at an AC frequency of 10 Hz to 100 Hz for switching to a transparent state, and / or operates at an AC frequency of less than 1 Hz for switching to a non-transparent state.

[0298] Clause 37. An optical modulator as described in any of the preceding clauses, wherein the size of the nanoparticles is from 10 nm to 1000 nm, preferably from 100 nm to 500 nm.

[0299] Clause 38. A light modulator as described in any of the preceding clauses, wherein the particles are adapted to absorb light with wavelengths from 10 nm to 1 micrometer.

[0300] Clause 39. An optical modulator as described in any of the preceding clauses, wherein the distance between the first substrate and the second substrate is less than 500 µm.

[0301] Clause 40. The optical modulator as described in any of the preceding clauses, wherein the dynamic viscosity of the fluid is 500 mPa·s or less.

[0302] Clause 41. An optical modulator as described in any of the preceding clauses, wherein the relative constant εr of the fluid is less than 100.

[0303] [method] [ ] Clause 42. A method for modulating light, the method comprising: - Applying a potential to one or more driving electrodes of one or two opposing substrates to obtain an electromagnetic field between the driving electrodes, thereby providing electrophoretic movement of the particles toward or away from one of the driving electrodes, thereby causing modulation of light passing through the substrates, wherein at least one or both of the two opposing substrates are as described in any of the preceding clauses.

[0304] Clause 43. The method of modulating light as described in Clause 42 includes using an alternating current having two phases, wherein the potential is between -220 V and +220 V and the current is between -100 µA and +100 µA.

[0305] Clause 44. A temporary or non-temporary computer-readable medium comprising data representing instructions that, when executed by a processor system, cause the processor system to perform the methods of Clause 42 or 43.

[0306] [picture] [9a] Showing a computer-readable medium 1000 having a writable portion 1010 including a computer program 1020 and a computer-readable medium 1001 also having a writable portion including a computer program. According to one embodiment, the computer program 1020 includes instructions for causing a processor system to operate an optical modulator. For example, the processor system may be connected to an optical 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 suitable embodiments are contemplated. Furthermore, it will be understood that although the computer-readable medium 1000 is shown herein as an optical disc, the computer-readable medium 1000 may be any suitable 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 a processor system to perform the optical modulator method.

[0307] [picture] [9b] A schematic representation of a processor system 1140 according to one embodiment of a controller for an optical modulator is shown. The processor system includes one or more integrated circuits 1110. The architecture of the one or more integrated circuits 1110 is schematically shown in FIG. 9b. Circuit 1110 includes a processing unit 1120 (e.g., CPU) for running computer program components to perform a method according to an embodiment and / or implement its modules or units. Circuit 1110 includes memory 1122 for storing program code, data, etc. A portion of memory 1122 may be read-only. Circuit 1110 may include communication elements 1126, such as an antenna, connector, or both and the like. Circuit 1110 may include dedicated integrated circuit 1124 for performing part or all of the processing defined in the method. Processor 1120, memory 1122, dedicated IC 1124 and communication elements 1126 may be interconnected with each other via interconnects 1130 (e.g., buses). The processor system 1140 can be configured to use antennas and / or connectors for contact communication and / or contactless communication.

[0308] For example, in one embodiment, the processor system 1140 (e.g., the device) may include processor circuitry and memory circuitry, the processor being configured to execute software stored in the memory circuitry. For example, the processor circuitry may be an Intel Core i7 processor, an ARM Cortex-R8, etc. In one embodiment, the processor circuitry may be an ARM Cortex M0. The memory circuitry may be ROM circuitry or non-volatile memory, such as flash memory. The memory circuitry may also be volatile memory, such as SRAM memory. In the latter case, the device may include a non-volatile software interface configured to provide software, such as a hard drive, a network interface, etc.

[0309] A controller for use in an optical modulator (e.g., for controlling the voltage applied to the electrodes) may include processor circuitry, but may or alternatively include a state machine.

[0310] It should be noted that the embodiments mentioned above are illustrative and not limiting of the subject matter disclosed herein, and those skilled in the art will be able to design many alternative embodiments.

[0311] In the scope of a patent application, no element symbol placed in parentheses shall be construed as limiting the scope of the patent application. The use of the verb "comprise" and its inflections does not exclude the presence of elements or steps other than those described in a technical solution. 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" preceding a list of elements indicate the selection of all or any subset of elements from that list. For example, the expression "at least one of A, B, and C" should be understood to include only A, only B, only C, both A and B, both A and C, both B and C, or all A, B, and C. The subject matter currently disclosed can be implemented by hardware comprising several distinct elements and by a suitably programmed computer. In a device technical solution enumerating several parts, several of these parts can be embodied by one and the same hardware item. The fact that a particular measure is referenced in different subsidiary technical solutions does not itself indicate that one combination of such measures cannot be used advantageously.

[0312] In the scope of the patent application, the symbols in parentheses refer to element symbols in the drawings of illustrative embodiments or formulas of embodiments, thereby increasing the understandability of the technical solution. These symbols should not be interpreted as limiting the technical solution.

[0313] 10: Optical modulator 11: First substrate / substrate / top substrate 12: Second substrate / substrate / bottom substrate 13: Electrode 13a: Electrode 13b: Electrode 14: Electrode 14a: Electrode 14b: Electrode 15: Fluid 16: Controller 20: Cars 21: Light modulator / window 30: Particles 40: Optical modulator 41: First substrate / substrate / outer substrate 42: Second substrate / substrate 43: Third substrate / substrate / outer substrate 46: Controller 100:Substrate 101:Substrate 102:Substrate 110: Drive bus 110': Drive bus 111-114: Main line / drive electrode 119: Connecting Zone 120: Drive bus 120': Drive bus 121-124: Main line / drive electrode 129: Connecting Zone 131: Interleaved Electrode / Electrode 132: Interleaved Electrode 133: Interleaved Electrode 134: Interleaved Electrode / Electrode / Wire 140: Constructing Blocks 141: Constructing blocks / blocks 142: Constructing blocks / blocks 143: Constructing blocks / blocks 144: Constructing blocks / blocks 191: Direction / First Direction 192: Direction / Second Direction 203:Substrate 204:Substrate 211: Constructing Blocks 212: Constructing Blocks 221: Constructing Blocks 222: Constructing Blocks 251: Constructing Blocks 252: Constructing Blocks 261: Constructing Blocks 262: Constructing Blocks 501: Optical Modulator 502: Optical modulator 511: Transparent substrate / First transparent substrate / First substrate / Substrate 512: Transparent substrate / Second transparent substrate / Second substrate / Substrate 521: Driving electrode / electrode 522: Driving electrode / electrode 523: Particle 524: Optical layer 531: Spacer 541: Patterned element 542: Patterned element 543: Patterned Elements 544: Patterned Components 601: Substrate / Transparent substrate 602: Substrate / Transparent substrate 611: Driving electrode 612: Driving electrode 621: Patterned element 622: Patterned element 631: Virtual Cutting Line / Line 632: Virtual scale, 1 micrometer 642: Main wavefront / wavefront 643: Optical modulator 644: Transverse Twisted Wavefront 645: Driving electrode 653: Optical modulator 654: Corrected wavefront 655: Patterned element 661: Height 662: Diameter 663: Distance between objects 711:Transparent substrate / substrate 712: Optical layer side / side 721: Driving electrode / electrode 745: Patterned Components 746: Patterned Components 751: Coating / Protective Coating 752: Coating / Protective Coating 753: Coating / Combined Coating 810: Method 811: Steps / Provided 812: Steps / Application 813: Steps / Application 820: Method 821: Steps / Provided 822: Steps / Application 823: Steps / Sealing 830: Method 831: Steps / Application 832: Steps / Changes 1000: Computer-readable media 1001: Computer-readable media 1010: Writable portion 1020: Computer Programs / Data 1110: Integrated circuits / circuits 1120: Processing Unit / Processor 1122: Memory 1124: Dedicated Integrated Circuit 1126: Communication Components 1130: Interconnector 1140: Processor System

Claims

1. A transparent substrate for use in an optical modulator, the substrate including at least one driving electrode (111-114, 121-124) applied to a first surface of the substrate, the driving electrode being patterned across the substrate and configured to receive a potential, thereby modulating the optical properties of the optical modulator, wherein nano- and / or micro-patterned elements are applied to the surface of the substrate to alter the phase, amplitude, and / or polarization of light interacting with the substrate, wherein the patterned elements on the substrate include transparent and conductive patterned elements, the patterned elements being configured to receive a potential to provide control over the optical modulation in the optical modulator, and wherein the patterned elements are individually electrically addressable.

2. The substrate of claim 1, wherein the patterned elements have a maximum diameter in a two-dimensional cross-section parallel to the substrate, the diameter being at most 10 micrometers, at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers, and / or the minimum distance between two patterned elements is at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers, and / or the minimum distance between two patterned elements is at least 10 nanometers, at least 50 nanometers, at least 100 nanometers, 200 nanometers, or 400 nanometers, the patterned elements having at least two discontinuous edges, the minimum distance between two points on each of the discontinuous edges being at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers.

3. The substrate of claim 1, wherein the patterned elements form a metasurface.

4. The substrate of claim 1, wherein the patterned elements extend from the surface and have a maximum height in a direction perpendicular to the substrate, the height being at most 2 micrometers, at most 1 micrometer or at most 500 nanometers, preferably between 100 nanometers and 1000 nanometers.

5. The substrate of claim 1, wherein the patterned elements are applied to the first surface, and / or wherein the patterned elements are applied to a second surface opposite to the first surface.

6. The substrate of claim 1, wherein the patterned elements are configured to compensate for optical artifacts of the light modulator caused by the driving electrodes.

7. The substrate of claim 6, wherein the optical artifact is any of the following: diffraction, refraction, scattering, or disturbance of light when passing through or reflected from the substrate.

8. The substrate of claim 1, wherein the patterned elements are configured to form a diffraction effect opposite to that formed by the driving electrodes of the modulator.

9. The substrate of claim 1, wherein the patterned elements provide optical wavelength control to filter light passing through the substrate according to the wavelength.

10. The substrate of claim 1, wherein the patterned elements alter the wavefront of light passing through the substrate to generate a holographic image.

11. The substrate of claim 1, wherein the patterned elements alter the wavefront of light reflected through the substrate and compensate for optical aberrations generated by the driving electrodes.

12. The substrate of claim 1, wherein the patterned elements provide optical polarization control to manipulate linear or circular polarization.

13. The substrate of claim 1, wherein the patterned elements include elements with controllable shapes, the elements being configured to provide control over the changes in the phase, amplitude and / or polarization of light interacting with the substrate.

14. The substrate of claim 1, wherein the light modulator is configured for use in a defined spectral range including visible light and / or infrared light, wherein the total transmittance of the patterned elements in the defined spectral range is at most 10%.

15. The substrate of claim 1, wherein the patterned elements include a phase-changing material having optical distortion that depends on external factors such as temperature, pressure and / or electric field.

16. The substrate of claim 1, wherein the patterned elements are configured to interact with particles in the optical layer of the light modulator.

17. The substrate of claim 1, wherein the patterned elements are applied to the first surface in the form of a regular grid covering at least a portion of the first surface.

18. A method of manufacturing a substrate as claimed in claim 1, the method comprising providing the substrate, applying the driving electrode to a first surface of the substrate, and applying the patterned elements to a surface of the substrate.

19. An optical modulator comprising a first substrate as claimed in claim 1, a second substrate, and an optical layer extending between the first substrate and the second substrate, wherein the optical properties of the optical modulator can be modified at least by applying a potential to the driving electrode.

20. The optical modulator of claim 19, wherein the optical layer includes charged particles, the patterned elements on the first substrate include transparent and conductive patterned elements, and the optical modulator is configured to apply a potential to the conductive patterned elements, thereby causing the charged particles to align with the conductive patterned elements, thus modulating the optical properties of the patterned elements.

21. The light modulator of claim 19, wherein the patterned elements are configured to focus light incident on the first substrate into the optical layer.

22. A method for calibrating an optical modulator as claimed in claim 19, the method comprising providing the optical modulator, obtaining information about the distortion and / or transparency of the optical modulator from an image sensor viewing the optical modulator, and deriving a control signal for controlling the optical modulator during an operation phase.

23. The method of claim 22, further comprising obtaining information about the orientation of the light modulator from an orientation sensor applied to the light modulator.

24. A method for controlling an optical modulator, the optical modulator being the optical modulator of claim 19, the method comprising applying a potential to a driving electrode to modulate an electromagnetic field in an optical layer, thereby providing electrophoretic and / or dielectric migration of particles in the optical layer, thereby causing modulation of light passing through the substrates, wherein the phase, amplitude and / or polarization of the light passing through the substrates is further altered by patterned elements applied to the surface of the substrates.

25. The method of controlling an optical modulator as claimed in claim 24, wherein the patterned elements include a phase-changing material having optical distortion dependent on external factors such as temperature, pressure and / or electric field, and / or wherein the patterned elements are conductive and have optical distortion dependent on external factors including potential, the method comprising modulating the external factors to modulate the optical distortion.

26. A non-transitory computer-readable medium (1000), the transient or non-transitory computer-readable medium including data (1020) representing instructions that, when executed by a processor system, cause the processor system to perform any of the methods described in claims 22 to 25.

Images