Substrates having micro and / or nano-patterned elements for optical modulators and optical modulation

Abstract

Some embodiments are directed to a transparent substrate for use in a light modulator. The substrate has at least one drive electrode applied to a first surface of the substrate. The drive electrode may be arranged in a pattern across the substrate and may receive an electrical potential to cause modulation of an optical property of the light modulator. A patterning element is applied to the surface of the substrate to modify the phase, amplitude, and / or polarization of light interacting with the substrate.

Description

Technical Field

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

Background Art

[0002] Known optical modulators are disclosed in WO2022023180, which is incorporated herein by reference. Known optical modulators comprise a transparent or reflective substrate. A plurality of electrodes are applied to the substrate in a pattern across the substrate. A controller may apply a potential to the electrodes to obtain an electromagnetic field between the electrodes and provide electrophoretic movement of particles towards or from the electrodes.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Means for Solving the Problems

[0004] It would be advantageous to have an improved optical modulator. In particular, it would be advantageous to have an improved transparent substrate for use in an optical modulator. In an embodiment of the substrate, micro and / or nanopatterned elements are applied to the surface of the substrate. The patterned elements change the phase, amplitude, and / or polarization of light interacting with the substrate. Light interacting with the substrate includes light passing through the surface. Light interacting with the substrate may include light reflected from the substrate.

[0005] The patterned element has a shape, for example, a 2D or 3D shape parallel to the substrate, and a distribution selected to perform the desired optical modulation. The patterned element may be manufactured by patterning, which may include a process of creating nanostructures across the surface of the material, in this case the substrate. In one embodiment, the patterned element may be transparent or not. Transparent patterned elements have the advantage of a smaller reduction in transmittance, but the optical effect of the element may be smaller, for example, if the element has a small refractive index.

[0006] In addition to the patterning elements, at least one driving electrode may also be applied to the first surface of the substrate, and the driving electrode is arranged in a pattern across the substrate. The electrode is positioned to receive potential and result in modulation of the optical properties of the optical modulator. In particular, the optical modulator may have an optical layer adjacent to the substrate. Particles in the optical layer may be under the control of the electrode, for example, under electrophoretic control.

[0007] For example, metasurfaces formed by patterned elements allow for the correction of optical artifacts caused by the presence of driving electrodes on the substrate. In particular, diffraction and / or rainbowing can be reduced by adding nanoelements. For example, metasurfaces may have thin-film coatings that create an electromagnetic optical system. Typically, metasurface designs are selected or optimized, especially for electrode designs. Using the same metasurface for electrodes with different patterns may not work well.

[0008] For example, metasurfaces formed by patterned elements may allow for the introduction of optical effects, in addition to potentially correcting artifacts. These optical effects include 3D rendering, holograms, and possibly lenses with different focal points.

[0009] Metasurfaces are layers of subwavelength-scale nanostructures that can be used to design thin, optically functional devices. Various metasurface-based optical devices, also known as planar optical devices, have been realized with distinct performance characteristics.

[0010] The nanodevice may be applied to the same surface of the substrate or to the opposite surface of the substrate.

[0011] The nanodevice may be configured to reduce reflection from the substrate and therefore improve the dark state of the optical modulator, for example, by deepening the black level.

[0012] Embodiments of the subject matter disclosed herein further include methods for manufacturing a substrate, optical modulators, methods for calibrating optical modulators, methods for controlling optical modulators, and computer-readable media.

[0013] Further details, aspects, and embodiments are described by reference to the drawings, merely as examples. Elements in the drawings are shown for simplification and clarity and are not necessarily drawn according to a constant proportional scale. In the drawings, elements corresponding to elements already described may have the same reference numerals. [Brief explanation of the drawing]

[0014] [Figure 1a] This diagram schematically shows an example of a building block embodiment. [Figure 1b] This figure schematically shows an example of a substrate embodiment. [Figure 1c] This figure schematically shows an example of a substrate embodiment. [Figure 1d] This figure schematically shows an example of a substrate embodiment. [Figure 1e] This figure schematically shows an example of a substrate embodiment. [Figure 1f] This figure schematically shows an example of a substrate embodiment. [Figure 2a] This figure schematically shows an example of a substrate embodiment. [Figure 2b] This figure schematically shows an example of a substrate embodiment. [Figure 2c] It is a diagram schematically showing an example of an embodiment of a substrate. [Figure 2d] It is a diagram schematically showing an example of an embodiment of a substrate. [Figure 2e] It is a diagram schematically showing an example of an embodiment of a substrate. [Figure 2f] It is a diagram schematically showing an example of an embodiment of a substrate. [Figure 3a] It is a diagram schematically showing an example of an embodiment of an optical modulator. [Figure 3b] It is a diagram schematically showing an example of an embodiment of an optical modulator. [Figure 3c] It is a diagram schematically showing an example of an embodiment of a vehicle. [Figure 4a] It is a diagram schematically showing an embodiment of an optical modulator. [Figure 4b] It is a diagram schematically showing an embodiment of an optical modulator. [Figure 4c] It is a diagram schematically showing an embodiment of an optical modulator. [Figure 5a] It is a diagram schematically showing an example of an embodiment of an optical modulator. [Figure 5b] It is a diagram schematically showing an example of an embodiment of an optical modulator. [Figure 5c] It is a diagram schematically showing an example of an embodiment of an optical modulator. [Figure 6a] It is a diagram schematically showing an example of an embodiment of a transparent substrate for use in an optical modulator. [Figure 6b] It is a diagram schematically showing an example of an embodiment of a transparent substrate for use in an optical modulator. [Figure 6c.1] It is a diagram schematically showing an example of an embodiment of a transparent substrate for use in an optical modulator. [Figure 6c.2] It is a diagram schematically showing an example of an embodiment of a transparent substrate for use in an optical modulator. [Figure 6d.1] It is a diagram schematically showing an example of an optical modulator without a patterning element. [Figure 6d.2] It is a diagram schematically showing an example of an embodiment of an optical modulator having a patterning element. [Figure 6e.1] This figure schematically shows an example of an optical modulator having a conductive patterning element in an inactive state. [Figure 6e.2] This figure schematically shows an example of an optical modulator having an active conductive patterning element. [Figure 7a] This figure schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. [Figure 7b] This figure schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. [Figure 7c] This figure schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. [Figure 7d] This figure schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. [Figure 7e] This figure schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. [Figure 7f] This figure schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. [Figure 7g] This figure schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. [Figure 8a] This figure schematically shows an example of one embodiment of a method for manufacturing a substrate, similar to the case of the first embodiment. [Figure 8b] This figure schematically shows an example of one embodiment of a method for manufacturing an optical modulator, similar to the case of one embodiment. [Figure 8c] This figure schematically shows an example of one embodiment of a method for operating an optical modulator, similar to that in one embodiment. [Figure 9a] This figure schematically illustrates a computer-readable medium having a writable portion containing a computer program, according to an embodiment. [Figure 9b] This figure schematically illustrates a representation of a processor system according to an embodiment. [Modes for carrying out the invention]

[0015] While the subject matter of this disclosure can take many different forms, one or more specific embodiments will be shown in the drawings and described herein in detail, with the understanding that this disclosure is intended to be illustrative of the principles of the subject matter and is not intended to limit the disclosure to any particular embodiment shown and described.

[0016] In the following, for the sake of understanding, the elements of the embodiments will be described in their operating state. However, it will be clear that each element is configured to perform the function described as being performed by that element. Furthermore, the subject matter of this disclosure is not limited to the embodiments alone, but also includes all other combinations of features described herein or described in dependent claims that differ from each other.

[0017] For example, a substrate is disclosed for use in an optical modulator, particularly for use in dynamic glazing. The substrate is transparent, and at least one driving electrode is applied to the surface of the substrate, the driving electrode extending in a pattern across the surface of the first substrate. Interestingly, when in use within an optical modulator, it is advantageous to have patterned elements applied to the surface of the substrate to modify, for example, correct the light interacting with the substrate. The patterned elements are arranged in a pattern on the substrate. The pattern may be repeatable, but this is not required. The pattern is made in a pattern according to the desired modulation of the light brought about by the patterned elements. For example, multiple patterned elements on the substrate together may form a metasurface.

[0018] Many types of optical modulators exist that use such substrates. Some known optical modulators are based on the principle of electrophoresis. For example, the substrate may have multiple interdigitated drive electrodes applied to it, for example, two electrodes, each of which is arranged in a pattern across the substrate, and the multiple interdigitated drive electrodes are arranged alternately relative to each other on the substrate. Having multiple interdigitated electrodes allows for local control of the electric field and enables control of the electrophoretic movement of particles.

[0019] Electrophoretic optical modulators are described more extensively herein and are used as motivational examples. In one embodiment, the optical modulator comprises a first substrate and a second substrate. At least one of the first and second substrates may have patterning elements according to one embodiment. For example, the first and second substrates may be arranged so that their inner surfaces face each other. Using substrates according to the embodiment has the effect of reducing optical interference, for example. An optical layer is placed between the first and second substrates. A driving electrode is placed to modulate the electric field in the optical layer. The optical layer contains a fluid containing particles, which are charged or can be charged. The particles can move under the control of the electric field. For example, a controller may be configured to apply a potential to the driving electrode to obtain an electromagnetic field at the driving electrode, providing electrophoretic motion of particles toward or from one of at least one driving electrodes, resulting in modulation of the optical properties of the optical modulator.

[0020] Below, several known optical modulators are discussed, and some options in terms of technique and electrodes are shown. These known substrates can be advantageously modified by applying patterned elements. These examples also show optical modulators with varying numbers of electrodes on the substrate.

[0021] International patent applications WO2011012499(A1) (included herein by reference) and WO2011131689 (included herein by reference) disclose electrophoretic display devices, for example, light modulators in the form of e-ink displays. Pixels of the display comprise a storage electrode and a field electrode, the storage electrode located in a storage area for accumulating charged particles away from the aperture area, and the field electrode occupies a field electrode area which is at least a portion of the aperture area of ​​the pixel, and the charged particles are movable between the storage electrode and the field electrode. In one embodiment, the two electrodes are applied on a single substrate. The substrate may have patterned elements applied to its surface to modify, for example, correct light interacting with the substrate.

[0022] U.S. Patent No. 1,0921678, titled “Electrophoretic device,” which is incorporated herein by reference, describes an electrophoretic device having only one patterned electrode on one of two substrates. For example, one substrate having an electrode according to U.S. Patent No. 1,0921678 may be replaced with a substrate according to one embodiment having a single electrode. For example, one embodiment comprises a first transparent substrate having a field electrode, and a second substrate facing the first substrate having a storage electrode. The first and second substrates enclose pixels with fluid and particles. During use, the electromagnetic fields applied to the field electrode and the storage electrode provide for the movement of particles from the field electrode and the storage electrode, and vice versa. The substrate may have patterned elements applied to the surface of the substrate to modify, for example, correct the light interacting with the substrate.

[0023] U.S. Patent No. 8,054,535 (B2) (included herein by reference) and U.S. Patent No. 8,384,658 (B2) (included herein by reference) provide examples of alternatives to electrophoretic photomodulators in which one of two substrates has two patterned electrodes.

[0024] Patterned electrodes are also used in dielectrophoretic photomodulators. For example, U.S. Patent Application No. 2005185104(A1) (included herein by reference) and U.S. Patent Application No. 20180239211(A1) (included herein by reference) illustrate dielectrophoretic photomodulators having a substrate with patterned electrodes. Any of these cited electrophoretic or dielectrophoretic photomodulators may be configured by applying patterned elements to the surface of a substrate to modify, for example, correct the light interacting with the substrate.

[0025] The paper “Reversible Metal Electrodeposition Devices: An Emerging Approach to Effective Light Modulation and Thermal Management,” included by reference, also shows a substrate on which patterned electrodes are applied. The patterned electrodes may be advantageously arranged according to the embodiment.

[0026] The substrate embodiment may be used in electrochromic devices (ECDs). Electrochromic devices (ECDs) continuously but reversibly control optical properties such as optical transmission, absorption, reflection, and / or emittance by applying voltage (electrochromism). This property allows electrochromic devices to be used for applications such as smart glass, electrochromic mirrors, and electrochromic display devices.

[0027] Electrochromic devices are described, for example, in the paper "Silver grid electrodes for faster switching ITO-free electrochromic devices" by Antonio California et al., which is included herein by reference. That paper describes the preparation of electrochromic devices, in this case, ITO-free electrochromic devices.

[0028] Electrochromic devices use electrically conductive electrodes applied to a substrate. The cited paper uses a silver grid created using silver ink as the electrically conductive electrode. Electrochromic devices may contain electrochromic materials. The cited paper uses poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). In an electrochromic device, at least one driving electrode, such as an electrically conductive electrode, is applied to the substrate. The driving electrode is arranged in a pattern across the substrate. The cited paper discloses two different grid patterns, a regular hive and a regular ladder design. See Table 1 and Figure 3 of the cited paper.

[0029] In the cited paper, electrodes can be applied to a substrate by screen printing polyethylene terephthalate (PET) onto the substrate. Electrodes are typically electrically conductive materials, such as metals or metal oxides. In the cited paper, silver ink was used to screen print a grid onto the PET using a RokuPrint RP 2.2 instrument and a 180-wired mesh. Samples were allowed to dry in an oven at 130°C for 15 minutes. One or two layers of PEDOT:PSS SV3 were subsequently printed on top of these silver grids by screen printing. Patterned elements can be applied to the surface of the substrate to alter the light interacting with it, for example, to form a metasurface.

[0030] Another example of an electrochromic device is given in U.S. Patent No. 5,161,048, which is included herein by reference and has the title “Electrochromic window with metal grid counter electrode and acidic polyelectrolyte”. For example, an electrochromic device may comprise a transparent electrochromic film and an ion-conducting layer disposed between pairs of electrodes. A metal grid electrode is provided for the electrode. Figure 1 of the patent shows a metal grid according to the cited patent. To form a counter electrode, the metal grid is disposed adjacent to a second glass substrate.

[0031] For example, in an embodiment of an electrochromic device, the electrochromic device may comprise a transparent substrate, an electrically conductive electrode member, a transparent electrochromic film in contact with the electrically conductive electrode member, 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 vary depending on the embodiment.

[0032] The substrate according to the embodiment may be advantageously applied in several other technologies. For example, the optical modulator may be a dielectrophoretic optical modulator, as shown, for example, in U.S. Patent Application No. 20050185104(A1), which is included herein by reference. The substrate according to the embodiment may also be used in other electrowetting and OLED applications.

[0033] In OLEDs and electrowetting, electrodes are required on only one of multiple substrates. The substrate having the electrodes may vary depending on the embodiment.

[0034] In applications such as glazing optical modulators, both substrates are typically transparent. In other applications, such as televisions and e-readers, only one substrate may be transparent.

[0035] In one embodiment, the substrate has patterned elements applied to its surface to modify, for example, correct the light interacting with the substrate.

[0036] In Figures 1a-4c, the nanodevices are not visible in the figures.

[0037] Figure 1b schematically shows an example of one embodiment of the substrate. The substrate is particularly useful for use, for example, in optical modulators of the type described herein. Multiple inter-mating drive electrodes are applied to the substrate across it. Two electrodes are shown in Figure 1b.

[0038] An example of substrate motivation is its use in electrophoretic optical modulators. Typically, an electrophoretic optical modulator comprises at least two substrates, each of which has at least two driving electrodes. While not required, an electrophoretic optical modulator may, for example, comprise a single substrate with two electrodes and a counter substrate with one electrode. In either case, preferably, at least one of the substrates in the optical modulator is configured according to the embodiment.

[0039] An embodiment of the optical modulator comprises a first substrate and a second substrate according to the embodiment. The first and second substrates are arranged with their inner surfaces facing each other. At least one drive electrode is applied to the inner surface of the first substrate. An optical layer is placed between the first and second substrates. A controller is configured to apply a potential to at least one drive electrode that results in modulation of the optical properties of the optical modulator. One or both of the first and second substrates are transparent and / or translucent.

[0040] Many different types of optical modulators exist that use at least one driving electrode applied to a substrate. Interference is a common problem in the field of optical modulators, as light passes through the substrate. Optical layers and controllers may be configured to modulate optical properties using potential-dependent effects on the driving electrode, examples including dielectrophoretic and electrophoretic effects. For example, an optical modulator may involve the modulation of particles placed within the optical layer. The number of driving electrodes can range from one on a single substrate to multiple driving electrodes on one or both substrates.

[0041] The optical layer placed between the first and second substrates may, for example, contain particles suspended in a fluid. The controller may be configured to apply a potential to the driving electrode, causing the particles to move and thus modulating the optical properties of the optical modulator.

[0042] In embodiments, the particles include charged or chargeable particles, and the controller is configured to apply a potential to the driving electrodes to obtain an electromagnetic field that provides electrophoretic motion for the particles. In embodiments, the electromagnetic field is located between at least two driving electrodes, which are located on the same substrate or on different substrates.

[0043] In the 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, thereby enabling the particles to move under the action of dielectrophoretic force.

[0044] The controller may apply an electrical signal to one or more of the drive electrodes. Embodiments controlling the electrophoretic force may use signals including DC and / or AC signals. Embodiments controlling the electrophoretic force may use signals including DC and / or AC signals.

[0045] Figure 1b shows two drive electrodes on the same surface. The two drive electrodes are shown in Figure 1b with two different dashed line styles. For example, there may be three or more electrodes on the same surface of the substrate to facilitate finer control of the voltage difference across the substrate. The drive electrodes are applied to the same surface of the substrate. Applying electrodes to the substrate may be done by lithography, for example, using a mask that represents the electrode pattern. Electrodes may also be applied by embedding them in the substrate.

[0046] The drive electrodes are electrically connected, for example, having the same potential everywhere. The drive electrodes may include a drive bus and a main line. At a minimum, the main line is mated with the main lines of further drive electrodes. Typically, the drive electrodes extend in substantially straight lines across the substrate, while the main lines are intricate.

[0047] In an embodiment, each of the two substrates of the optical modulator has two electrodes located on its inner surface. However, as stated, multiple electrodes on one or both substrates are not required. For example, an embodiment of the optical modulator comprises a first substrate and a second substrate. For example, the first substrate may have one drive electrode, and the second substrate may not have a drive electrode. For example, the first substrate may have two drive electrodes, and the second substrate may have one drive electrode. For example, the first substrate may have two drive electrodes, and the second substrate may have two drive electrodes. For example, the first substrate may have three or more drive electrodes, and the second substrate may have two or more drive electrodes.

[0048] Optical modulators, however, where each substrate has two drive electrodes, are used as a motivational example. A substrate design featuring two drive electrodes may be configured to have a single drive electrode, for example, by connecting two drive electrodes or by removing one of multiple drive electrodes. Configuring the substrate in this way may make it suitable for use in different technologies.

[0049] Each of the multiple drive electrodes is arranged in a pattern across the substrate. The multiple drive electrodes are arranged alternately on the substrate relative to each other. Typically, a drive electrode has multiple main lines, each of which extends across the substrate. The main lines of the drive electrodes are alternating, for example, inter-mating. For example, in Figure 1b, the first drive electrode has main lines 111-114, and the second drive electrode has main lines 121-124. Each drive electrode is driven by its drive bus. Figure 1b shows two drive buses: drive bus 110 and drive bus 120. The drive electrodes also serve to connect the main lines together. For example, in Figure 1b, drive bus 110 drives and connects main lines 111-114, and drive bus 120 drives and connects main lines 121-124. There can be more than four main lines than shown in this example. The use of main lines is advantageous for reducing the length of the electrodes, but it is not necessary. While a design using only one main line per drive electrode is possible, having multiple main lines is advantageous.

[0050] Multiple main lines of the first and second electrodes are arranged alternately with respect to each other on the substrate.

[0051] Motivational applications for substrates such as substrate 100 may be applied in domestic housing, offices, greenhouses, cars, and similar applications, such as smart glazing in optical modulators. The level of transparency or reflectivity of smart glazing can be electrically adapted. For example, in smart glazing, two substrates such as substrate 100 are stacked such that the surfaces on which two electrodes are applied face each other. A fluid containing particles is enclosed between the two substrates. Embodiments of smart glazing are discussed further below. In embodiments, electrodes, for example, two or more electrodes, are applied to one surface of each substrate. For example, to facilitate the stacking of three or more substrates, one, two, or more electrodes may be present on the other surface of substrate 100.

[0052] The following embodiments illustrate examples of modulating transparency or reflectivity levels. Optical modulators may be configured for other optical effects. For example, if desired, embodiments may be modified for different levels of translucency instead of different levels of transparency. If desired, the type of particles used in embodiments may be varied, for example, for particles that absorb or reflect at different wavelengths and how specular or diffuse the reflection is. For example, in embodiments, optical modulators can modulate different levels of reflection. Particles may also emit light. Stacking multiple optical layers further increases the possibilities.

[0053] Having two sets of alternating main lines is sufficient to provide electrically configurable glazing, and the two alternating sets allow the electric field in any part of the substrate to be controlled because the two opposing electrodes boundary that part from two opposing surfaces.

[0054] Interestingly, the pattern extending across the substrate by the drive electrodes is made up of multiple repeating building blocks. As shown in Figure 1b, the drive electrodes on substrate 100 show four blocks: blocks 141, 142, 143, and 144, all of which are substantially identical. The number of building blocks may be more than four. The building blocks repeat across the substrate in both directions, for example, a first direction 191, e.g., the x-direction shown horizontally in the figure, and a second direction 192, e.g., the y-direction shown vertically in the figure. The use of building blocks is advantageous because it enables manufacturing using a stepper machine. The use of building blocks is not required.

[0055] For example, Figure 1a schematically shows an example of an embodiment of building block 140. Building block 140 comprises a plurality of inter-mating electrodes extending in at least two directions across the building block. Four electrodes: electrodes 131-134 are shown in Figure 1a. When the building block is repeated across the substrate in two directions, the electrodes within the building block will form multiple main lines of drive electrodes, for example, forming drive electrodes. Note that building blocks are typically connected in a substrate electrode design tool. Typically, a building block has five or more electrode lines. For example, within the scope of the embodiment, between eight and twelve main lines are used. The number of electrode lines can, however, be much greater. For example, a building block may have many short electrode lines near the edges, and the edges connect to lines of other building blocks when the block is repeated. Taking such short derivatives into account, the number of lines can increase to, for example, 50. Obviously, using larger building blocks may also increase the number of electrode lines. In this embodiment, the number of electrode lines within the building block is between 8 and 50, or between 8 and 25, and so on.

[0056] The drive electrodes, formed by repeating building blocks, are connected to the drive bus. Typically, electrode lines within a building block are connected to electrode lines in neighboring blocks by merging the corresponding electrode lines, although this is not required. However, connection zones connecting the corresponding electrode lines may be inserted between repeating building blocks.

[0057] This step allows multiple main lines to be connected 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.

[0058] The electrodes shown in Figure 1a are alternately marked with dashed lines in the same dashed line style as in Figure 1b. In practice, it happens in this example that certain electrodes of the building block in Figure 1a always end up either within the first drive electrode or within the second electrode, for example, as indicated by the dashed line style in this case. This, however, is not always the case. Electrodes within a building block may end up as part of the first drive electrode or as part of the second drive electrode. This can change, for example, the repeating pattern of the building block as a result of the even or odd number of electrodes within the building block.

[0059] For example, a particular pattern of repeating building blocks may be used for an optical modulator having two drive electrodes, in which alternating main lines may be assigned to the two drive electrodes. However, the same pattern of repeating building blocks may be used for an optical modulator having three drive electrodes, in which all adjacent sets of the three main lines may be assigned to the three drive electrodes.

[0060] Furthermore, although the building blocks shown in Figure 1a are rectangular, this is not required. For example, the building blocks may be rectangular. In embodiments, the building block shape(s) may form a so-called tessellation. For example, the building blocks may be triangular, hexagonal, or even a combination of planar tessellations.

[0061] As mentioned, Figures 1a and 1b are schematic. This is especially true for the depiction of electrodes. The electrodes shown in Figure 1a are straight, however, in one embodiment, electrodes on building blocks are more intricate, for example, curved. By adapting the shape of the electrodes, undesirable diffraction effects can be altered.

[0062] In embodiments, the dimmable mirror comprises an optical modulator according to the embodiment. For example, the dimmable mirror comprises a transparent substrate, an optical layer, and a reflective substrate. One or both of the substrates are according to the embodiment. The dimmable mirror may be electrophoretic. Typically, each substrate has two electrodes, but this is not required.

[0063] Figure 1c schematically shows an example of an embodiment of substrate 101. Substrate 101 is similar to substrate 100, except that the main lines formed from electrodes on the building blocks are connected to the drive bus. In Figure 1a, a connection zone is inserted between the repeating building blocks and the drive buses 110 and 120. In the connection zone, main lines belonging to the same drive electrode are connected to the same drive bus. In Figure 1c, the drive bus is directly adjacent to the building block. Part of the building block is modified to avoid the drive bus connecting to the main lines of different drive electrodes.

[0064] For example, building block 141 may be a copy of building block 140, but electrode 134 is shortened so that the main line 122 (of which line 134 is part) does not connect to bus 110. In Figure 1c, the building blocks are substantially the same, except that a disconnection is introduced in some electrodes of the building block adjacent to the drive bus to avoid connecting the main line to the drive bus. All building blocks shown in Figure 1c are thus modified, but in the embodiment, the majority of building blocks, such as those not adjacent to drive buses 110, 120, are not modified.

[0065] Figure 1d schematically shows an example of an embodiment of the substrate 102. In this embodiment, each electrode within a building block connects the same opposing side of the building block. This results in the main lines formed by the electrodes on the building block connecting opposing sides of the substrate. In such a situation, having only two drive buses, each extending along opposing sides of the substrate, is sufficient to connect and drive the drive electrodes.

[0066] However, electrodes within a building block do not need to connect opposite edges of the building block. Typically, all electrodes within a building block will connect two edges of the building block, but these two edges do not need to be opposite. The reason for this is that electrodes may be continued by the next building block. In such situations, most main lines will still connect the same two opposite edges, but this may not happen at the edges of the substrate because there are no further building blocks there to carry the electrodes forward. To allow for more complex electrode designs with respect to building blocks, main lines may connect to the drive bus from two edges, for example, two adjacent edges of the substrate at the same corner of the substrate.

[0067] 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.

[0068] The advantage of this configuration is that the drive bus can be created in the same plane. This is not necessary, however. The drive bus can be connected from all three or four sides, if desired, for example, to further increase the design freedom for the building block. Various examples are shown herein.

[0069] It should be noted that drive electrodes, such as drive buses and / or main lines, are permitted to overlap. This is possible, for example, by providing a portion of dielectric material between the electrodes. For example, such overlapping electrodes may lie partially or completely in different planes of the substrate.

[0070] For example, in an embodiment, the first drive electrode may be deposed. Then, the dielectric is locally deposed, and finally, the second drive electrode is deposed. The dielectric is arranged to cover at least several points where the first and second electrodes intersect. Vias may be used for lower first drive electrodes, for example, to connect to a lower first drive electrode. Deposing the drive electrodes may include deposing the drive bus.

[0071] Figure 1e schematically shows an example of one embodiment of the substrate 203. In Figure 1e, the building block was copied multiple times.

[0072] Building block 211 was mirrored in the y-direction to form building block 221. Building block 221 was positioned directly below building block 211. Building block 211 was mirrored in the x-direction to form building block 212. Building block 212 was positioned directly to the right of building block 211. Building block 211 was mirrored in both the x-direction and the y-direction to form building block 222. For example, the mirroring may have the edges of the building blocks as the mirroring axes.

[0073] By mirroring the building blocks, it is ensured that drive buses with the same drive electrodes end up adjacent to each other on the substrate.

[0074] Figure 1f schematically shows an example of one embodiment of the substrate 204. In the substrate 204, building blocks are repeated across the substrate in different ways. Building block 251 was mirrored in the y direction to form building block 261. Building block 261 was positioned directly below building block 251. Building block 251 was rotated, for example, by 180 degrees, through point reflection, to form building block 252. Building block 252 was positioned directly to the right of building block 251. Building block 251 was mirrored in the x direction to form building block 262.

[0075] Figures 2a-2f schematically show examples of substrates having inter-mated electrodes. These may be implemented, for example, on a substrate having two electrodes connected alternately. Figures 2a-2d may be implemented on a substrate having multiple electrodes connected, for example, in a sequence of three, four, or more electrodes.

[0076] Figures 2e and 2f show designs with two drive electrodes on the surface of the substrate. Both designs can be modified to have only a single drive electrode on the surface of the substrate, for example, by removing one of the two drive electrodes. Such a modified design could, for example, be used in an optical modulator using a substrate with a single electrode.

[0077] The designs shown can be realized in a single plane without intersecting electrodes. In particular, when these designs are connected to two drive buses, intersecting electrodes are not required. When three or more drive electrodes are used, or when more complex electrode patterns are used, electrode intersections may be used or even required. However, such intersections are possible, for example, where two electrode lines intersect, and dielectric material may be placed between the electrodes. For example, such an insulator may be deposited at the intersection site. For example, the first drive electrode lies in a first plane of the substrate, and the second drive electrode lies in a second plane of the substrate.

[0078] The two substrates according to the embodiment may be combined to form an optical modulator. The optical modulator is particularly suitable for glazing. An exemplary embodiment of the optical modulator is shown below.

[0079] Figure 3a schematically shows an embodiment of the optical modulator 10 that may be applied in smart glazing.

[0080] References are made to the patent application PCT / EP2020 / 052379, which is incorporated herein by reference and includes a favorable design for a modulator, the design of which may be further improved by including, for example, electrodes, building blocks, and / or substrates as described herein.

[0081] The optical modulator 10 can be electronically switched 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 optical modulator 10 comprises a first substrate 11 and a second substrate 12 arranged opposite each other. At least two electrodes are applied to the inner surface of the first substrate 11: electrodes 13a and 13b are shown. These at least two electrodes are collectively referred to as electrode 13. At least two electrodes are applied to the inner surface of the second substrate 12: electrodes 14a and 14b are shown. These at least two electrodes are collectively referred to as electrode 14.

[0082] The fluid 15 is provided between the substrates. The fluid contains particles 30, such as nanoparticles and / or microparticles, which are charged or can be charged. For example, particles may inherently retain charge on their surface. For example, particles may be surrounded by charged molecules.

[0083] Electrodes are positioned to drive particles 30 to move toward or away from the electrodes, depending on the applied electric field. The optical properties of the optical modulator, in particular its transparency or reflectivity, depend on the location of the particles 30 in the fluid. For example, connections may be provided to apply an electromagnetic field to the electrodes.

[0084] At least one electrode, but preferably both electrodes 13 and 14, are shown schematically in the figures, depending on the embodiment.

[0085] In the embodiment, at least one of the electrode patterns on the first substrate and the electrode pattern on the second substrate has a calculated low pixelated noise metric that contributes to diffraction. Interestingly, the electrode patterns on the substrates may not individually satisfy the boundary with respect to their pixelated noise metrics, but their combination, i.e., their superposition, may satisfy it. Since this is the pattern that will be visible when viewed through an optical modulator, a low pixelated noise metric in the superposition will also contribute to low diffraction. Appropriate limits for the patterns on the first and / or second substrates or for the superposition include: less than 6.05%, 5%, or 4%.

[0086] In the example, substrates 11 and 12 may be optically transparent outside the electrodes, typically >95% transparent at the relevant wavelengths, e.g., >99% transparent. Considering the electrodes, transparency may be much lower, e.g., 70%. The term “optical” may, where applicable, refer to wavelengths visible to the human eye (approximately 380 nm–750 nm), and, where applicable, refer to a broader range of wavelengths including infrared (approximately 750 nm–1 μm) and ultraviolet (approximately 10 nm–380 nm) and their subselections. In exemplary embodiments of the optical modulator, the substrate material is selected from glass and polymer.

[0087] In another example, one substrate, such as the lower substrate 12, may be reflective or partially reflective, while the upper substrate 11 is transparent. The optical properties of the optical modulator, in particular its reflectivity, depend on the location of the particles 30 in the fluid. When the panel is open (vertically driven), the particles will be located approximately between the opposing electrodes of the two substrates, thereby allowing the incident light to pass through the transparent upper substrate and optical layer with relatively little obstruction and be reflected or partially reflected on the lower substrate.

[0088] The distance between the first substrate and the second substrate is typically less than 30 μm, for example, 15 μm. In an exemplary embodiment of the optical modulator, the distance between the first substrate and the second substrate is less than 500 μm, preferably less than 200 μm, preferably less than 100 μm, and more preferably less than 50 μm, for example, less than 30 μm.

[0089] In the example, the modulator may be made of a flexible polymer, and the rest of the device may be made of glass. The glass may be hard glass or flexible glass. If required, a protective layer may be provided on the substrate. If two or more colors are provided, two or more layers of flexible polymer may be provided. The polymer may be polyethylene naphthalate (PEN), polyethylene terephthalate (PET) (optionally having a SiN layer), polyethylene (PE), etc. In a further example, the device may be made of at least one flexible polymer. Thus, the modulator may be attached to any surface by means of an adhesive, for example.

[0090] Particle 30 may be configured to absorb light, thereby preventing certain wavelengths from passing through. Particle 30 may reflect light; for example, the reflection may be specular, diffusive, or somewhere in between. Particles may absorb some wavelengths and reflect others. Particles may also emit light, either similarly or instead, using, for example, phosphorescence, fluorescence, or similar phenomena. Even fluids can emit light, and their emittance can be modulated by changing the location of particles.

[0091] In exemplary embodiments of the optical modulator, the size of the nanoparticles is 20–1000 nm, preferably 20–300 nm, and more preferably less than 200 nm. In exemplary embodiments of the optical modulator, the nanoparticles / microparticles include a pigment coating and may preferably include a core. In exemplary embodiments of the optical modulator, the particle coating is made from a material selected from conductive and semiconducting materials.

[0092] In an exemplary embodiment of the optical modulator, the particles are configured to absorb light having wavelengths of 10 nm–1 mm, for example, 400–800 nm, 700 nm–1 μm, and 10–400 nm, and / or to absorb a portion of light having wavelength ranges (filters) and combinations thereof that fall within 10 nm–1 mm.

[0093] In an exemplary embodiment of the optical modulator, the particles are charged or can be charged. For example, the charge on a particle is 0.1e to 10e (5*10) per particle. -7 It may be -0.1C / m2.

[0094] In an exemplary embodiment of the optical modulator, the fluid is present in amounts such as 1-1000 g / m², preferably 2-75 g / m², more preferably 20-50 g / m², for example 30-40 g / m². A major advantage of this layout is that much less fluid and similar particles can be used.

[0095] In an exemplary embodiment of the optical modulator, the particles are present in amounts such as 0.01–70 g / m², preferably 0.02–10 g / m², for example, 0.1–3 g / m².

[0096] In an exemplary embodiment of the light modulator, the particles have colors selected from cyan, magenta, and yellow, and from black and white, and in combination thereof.

[0097] In an exemplary embodiment of the optical modulator, the fluid comprises one or more surfactants, emulsifiers, polar compounds, and compounds capable of forming hydrogen bonds.

[0098] The fluid 15 may be a nonpolar fluid having a dielectric constant less than 15. In an exemplary embodiment of the optical modulator, the fluid has a relative permittivity εr less than 100, preferably less than 10, for example less than 5. In an exemplary embodiment of the optical modulator, the fluid 15 has a kinematic viscosity greater than 10 mPa·s.

[0099] Electrodes 13a, 13b and electrodes 14a, 14b are in fluid contact with the fluid. The fluid may be in direct contact with the electrodes, or indirectly, for example, the fluid may be in contact with the second medium having the electrodes through a porous layer. In embodiments, the electrodes cover about 1-30% of the substrate surface. In embodiments, the electrodes have an electrical conductivity > 1 (at 20°C). * 10 7 The materials include electrically conductive materials having a resistivity less than 100 nΩm (at 273 K; for comparison, ITO, which is typically used, has 105 nΩm), similar to S / m. In embodiments of the optical modulator, the electrodes include copper, silver, gold, aluminum, graphene, titanium, indium, and combinations thereof, preferably copper. The electrodes may be in the form of microwires embedded in a polymer-based substrate, for example, copper microwires.

[0100] A connection may be provided for applying an electromagnetic field to the electrodes, and the electromagnetic field applied to the electrodes provides the movement of nanoparticles and microparticles from the first electrode to the second electrode and vice versa. A connection may be provided for applying an electromagnetic field to the electrodes. For example, in an exemplary embodiment of the optical modulator, the current is -100 to +100 μA, preferably -30 to +30 μA, more preferably -25 to +25 μA. For example, a power supply may be electrically connected to at least two electrodes. The power supply may be configured to provide waveform power. At least one of the amplitude, frequency, and phase may be configured to provide different states within the optical modulator. For example, a controller may be adapted to the mode of power.

[0101] The optical modulator 10 may have one or more segments, each segment being a single optically switchable entity whose size may vary. The substrate at least partially encloses the volume that may be a segment.

[0102] This device may include driver circuits for changing the appearance of (individual) segments by applying an electromagnetic field. Therefore, similarly, the appearance of the optical modulator or one or more parts thereof may be altered. For example, the segments may be at least 1 mm in diameter. 2 This design may have an area of ​​[a certain size]. This design allows for stacking to enable more colors; for example, in full-color applications, stacking two or three modulators may provide most or all of the colors, respectively.

[0103] Having one or more segments allows for localized control of the optical modulator, which is advantageous for some applications but not necessary. In the case of smart glazing, the optical modulator may be used with or without segments. For example, when applied in smart glazing, transparency or reflectivity may be locally controlled, for instance, to prevent sun-patch without reducing the overall transparency or reflectivity of the window. Segments can be relatively large, for example, having a diameter of at least 1 mm or at least 1 cm.

[0104] In an exemplary embodiment of the optical modulator, the substrates (11, 12) are aligned and / or the electrodes (13, 14) are aligned. For example, electrodes 13a, 13b and electrodes 14a, 14b may be aligned so as to face each other. In aligned substrates, electrodes on different substrates will be in a line when observed in a direction perpendicular to the substrates. When the optical modulator is disassembled and the substrates are together with electrodes facing upward, the electrode patterns are each mirror images of the other.

[0105] Aligning substrates may increase the maximum transparency or reflectivity of an optical modulator, while other times, when selecting an optical modulator for more criteria, such as a range of transparency or reflectivity, it may be better not to align the two substrates or to not align them completely. Optical modulators can be stacked. For example, two stacked optical modulators may be made from three substrates, with the central substrate having electrodes on both of its surfaces. In embodiments of the optical modulator, optionally, at least one substrate 11, 12 of the first optical modulator is the same as the substrate 11, 12 of at least one second optical modulator. In the case of stacked modulators, alignment may increase the maximum transparency or reflectivity, but it may be detrimental to other considerations, such as diffraction.

[0106] Figure 3b schematically shows an example of an embodiment of the optical modulator 40. The optical modulator 40 is similar to the optical modulator 10, except that it comprises multiple optical layers, two of which are shown in the example. There may be three or more optical layers. Each optical layer is located between two substrates. The optical modulator 40 can be considered a laminate of two-substrate optical modulators, as in Figure 3a. As shown, the optical modulator 40 comprises three substrates: a first substrate 41, a second substrate 42, and a third substrate 43. There is an optical layer between substrates 41 and 42, and an optical layer between substrates 42 and 43. The optical layers may be similar to the optical layers of the optical modulator 10. The controller 46 is configured to control the current on the electrodes of the substrates. For example, in Figure 3b, the controller 46 may be electrically connected to at least 4 × 2 = 8 electrodes.

[0107] Interestingly, the particles in multiple optical layers may differ, and as a result, multiple layers may be used to control more optical properties of the optical modulator. For example, particles in different optical layers may absorb or reflect at different wavelengths, and may have different colors, for example. This can be used by the controller 46 to create different colors and / or different color intensities on the panel. For example, a 4-substrate panel may have three optical layers, each with different colored particles, for example, cyan, yellow, and magenta. By controlling the transparency or reflectivity of different colors, a broad color spectrum can be created.

[0108] The surface of a substrate facing another substrate may be supplied with two or more patterns, for example, as in the embodiment. For example, the outer substrates 41 and 43 may receive electrodes only on their inner surfaces, while the inner substrate, for example, substrate 42, may have electrodes on both sides.

[0109] Substrates 41 and 42 can both be considered embodiments of an optical modulator. Similarly, substrates 42 and 43 can both be considered embodiments of an optical modulator.

[0110] Figure 3c schematically shows an example of an embodiment of a car 20 having smart glazing for a window 21. This is a particularly advantageous embodiment because, during driving, the level of incident light can often change rapidly. Using smart glazing in a car has the advantage that the light level can be maintained at a constant level by adjusting the transparency of the car window. Furthermore, the reduced diffraction effect improves safety by reducing driver distraction. The car 20 may include a controller configured to control the transparency or reflectivity of the window 21.

[0111] Smart glazing can be used in other glazing applications where the amount of incident light is variable, such as in buildings, offices, homes, greenhouses, and skylights. A skylight is a window placed in the ceiling to allow sunlight to enter a room.

[0112] An optical modulator may have two optical states, for example, a transparent state and an opaque state or a reflective state and an unreflective state. An optical modulator, for example, optical modulator 10 or optical modulator 40, - By creating an alternating current voltage on at least one of the first and second substrates, and 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, a second optical state is switched, for example, to a non-transparent state or a non-reflective state. - By creating an alternating current voltage between the first substrate and the second substrate, and 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, the optical state is switched to a first optical state, for example, a transparent state or a reflective state. It can be configured in this way.

[0113] The electrode pattern on the first substrate is at least partially arranged in the same pattern as the second electrode on the second substrate. Typically, the electrodes face each other, but the patterns of the first and second electrodes may be shifted relative to each other.

[0114] A protective coating may be provided on at least a portion of the inner surface area of ​​at least one of the first substrate and the second substrate.

[0115] The drive signal applied to the drive electrode typically has a fluctuating voltage. For example, a power supply may operate at an AC frequency to switch between a transparent and a non-transparent state. Such a signal may have a frequency between, for example, 1-1000 Hz. A balanced electrolytic current may be obtained by continuously switching the polarity of oppositely charged electrodes on and / or between the first and second substrates.

[0116] Figures 4a-4b schematically show side views of an embodiment of an optical modulator in use. Applying an electric field to electrodes on a substrate imparts an electric force to particles. Using this effect, particles can move around, thus bringing different transparency or reflectivity states into the optical modulator. The controller can control the electric field, for example, its amplitude, frequency, and phase. In embodiments, the controller is connected to at least four electrodes: two electrodes for each substrate. However, more electrodes may be used and connected to the controller; for example, three or more electrodes may be used for a substrate to better fine-tune grayscale and drive to opaque or non-reflective states. Multiple electrodes may also be used to support multiple segments on the substrate.

[0117] Figure 4a shows an optical modulator in a state where no electric field is applied. In Figure 4a, no electric force is yet applied to the particles 30 suspended in the fluid 15.

[0118] In the configuration shown in Figure 4a, the conductive electrode pattern on the upper substrate is perfectly or substantially aligned with the conductive electrode pattern on the lower substrate. The conductive electrode pattern may be deposited on a transparent or (partially) reflective glass substrate, or embedded in a plastic substrate or the like.

[0119] Alignment between the upper and lower electrode patterns contributes to a wider range of achievable levels of transparency or reflectivity. However, alignment is not necessary, as similar effects can be obtained without alignment. A similar range of transparency or reflectivity can be obtained without alignment.

[0120] Note that in these examples, references are made to the upper and lower boards, referring to the board that is higher or lower on the page. The same board may also be referred to as, for example, the front board and the rear board, because in glazing applications, the boards are aligned vertically rather than horizontally.

[0121] Figure 4b shows an optical modulator where, for example, at time P1, a potential +V1 is applied to each microwire electrode on the upper substrate, while a negative voltage, for example -V1, is applied to each microwire electrode on the lower substrate. Therefore, 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 closer to the electrodes on the upper substrate, and the particles substantially align with the upper electrodes. As a result, if both the upper and lower substrates are transparent, the transparency of the optical modulator 10 will increase. Similarly, for example, if the upper substrate is transparent and the lower substrate is reflective, the reflectivity of the optical modulator 10 will increase. If the solution contains positively charged particles, those particles will flow closer to the electrodes on the lower substrate, and those particles will substantially align with the lower electrodes.

[0122] Similar transparency or reflectivity can be achieved when, at a second time point P2 in the ON state, the voltages of the upper and lower electrodes are reversed in contrast to time point P1. At time point P2, the voltage of each electrode on the upper substrate is supplied with a negative potential -V1, while the voltage of the aligned electrodes on the lower substrate is supplied with a positive potential. This state is similar to the state shown in Figure 4b, but the upper and lower substrates are reversed. In this configuration, the transparency or reflectivity of the optical modulator 10 is also high.

[0123] Interestingly, transparency or reflectivity can be maintained while reducing corrosion damage to the electrodes by switching between, for example, the positive potential of the electrode on the upper substrate (and the negative potential on electrode 14), shown as electrode 13 in Figure 4b, and the positive potential of the electrode on the lower substrate, shown as electrode 14 in Figure 4b. This alternating electric field can be achieved by applying an alternating potential to the upper and lower electrodes.

[0124] Applying a waveform is optional but a useful measure to increase the lifespan of the optical modulator by reducing corrosion. Corrosion can form, for example, when using copper electrodes, because copper ions dissolve in the ionic fluid on one substrate and flow to the electrode on the opposing substrate, where the copper ions deposit. By applying a waveform, the direction of copper ion transport is frequently reversed, thus reducing corrosion damage. Between two time points P1 and P2, the corrosion currents between the two substrates are balanced, or substantially balanced, for example, >95%, for example, when a corrosion rate occurs on the electrode of the upper plate, there is a balancing deposit of copper on the lower electrode between each time point P1 and vice versa at time P2. Thus, particles continuously migrate or move between the upper and lower electrodes, the optical modulator or smart window is always on, while the dynamic electrolytic current between the upper and lower electrodes is constant, and therefore the net loss of electrode material on the upper and lower electrodes is zero or negligible.

[0125] Figure 4c shows how a reduced transparency or reflectivity state can be obtained. An AC voltage is applied to the same substrate. For example, in an embodiment, as shown in Figure 8c, a potential +V2 is applied to the first electrode, and the next immediately adjacent electrode has the opposite potential -V2, and so on. This can be achieved by applying a potential +V2 to electrode 13a and the opposite potential -V2 to electrode 13b. On the opposing substrate, a potential +V2 may be applied to electrode 14a and the opposite potential -V2 to electrode 14b. For example, the electrodes may be arranged so that the electrodes on the substrate are aligned, with electrodes on the upper substrate having opposing electrodes on the lower substrate, and vice versa. For example, to reduce transparency or reflectivity, opposing electrodes may receive the same potential, while neighboring electrodes receive the opposite potential. An embodiment is shown in Figure 4c, where four electrodes are indicated by reference numerals 13a, 13b, 14a, and 14b, and the rest of the electrodes continue to alternate.

[0126] By using this AC drive cycle between the upper and lower substrates, oblique and transverse electric fields are generated between the two substrates, thereby causing random diffusion of particles and creating a closed state in the optical modulator. As a result of this configuration, particles move obliquely and transversely between the upper and lower substrates, and the diffusion of particles into the visible aperture of the optical modulator contributes to the closed opaque state of the optical modulator.

[0127] Regarding the transparent state shown in Figure 4b, the waveform may be applied to the electrodes such that, for example, the electrode shown in Figure 4b becomes negative when it has a positive potential, and vice versa. As in the case of Figure 4b, applying the waveform between electrodes 13a and 13b, and between 14a and 14b, for example, reduces corrosion damage to the electrodes.

[0128] The AC drive cycle may be performed by using a mating line configuration that combines upper and lower electrode configurations, as shown in the plan view in Figures 1a, 1b, 2a-2f, etc.

[0129] The degree to which transparency or reflectivity increases or decreases in Figures 4b and 4c depends on the voltage difference and frequency difference. By varying the voltage difference, the amount by which transparency or reflectivity increases or decreases, respectively, can be controlled. For example, a curve representing light transmittance versus voltage may be determined, for example, by measurement. To obtain a specific level of light transmittance, for example, a specific level of transparency, for example, a specific grayscale level, a corresponding voltage, such as an AC voltage, may be applied. By interpolating the signal for a transparent state or a non-transparent state, a level between transparent and non-transparent can be obtained. Similarly, a curve representing light reflectance versus voltage may be determined, for example, by measurement. To obtain a specific level of reflectivity, a corresponding voltage, such as an AC voltage, may be applied. By interpolating the signal for a reflective state or a non-reflective state, a level between reflective and non-reflective can be obtained.

[0130] Different electrode patterns may be used for optical modulators. Each electrode pattern may provide a certain range of grayscale, e.g., levels of transparency or reflectivity, that the optical modulator can achieve. However, the specific range of grayscale for any given electrode pattern may differ from that of another electrode pattern. In other words, different patterns may give an increase in transparency or reflectivity or an increase in opacity, but the precise response to the drive signal depends on many factors, including the specific pattern used. Variations in the optical properties of an optical modulator may have good resolution, for example, less than 1 mm. Note that pixilation of the optical modulator is not required to achieve different visible optical patterns in the optical modulator, e.g., a logo.

[0131] This effect can be used to embed visible images into an optical modulator by locally altering the electrode pattern on the substrate of the optical modulator. For example, different electrode patterns may locally have grayscales with a permanent grayscale offset from each other. For example, maximum transparency or reflectivity may be altered by locally changing the electrode pattern or its pitch.

[0132] The result is areas on the optical modulator having different intensities of grayscale, e.g., different grayscales, or different intensities of coloration. The areas may, however, have the same color point. In embodiments, they may switch together with the rest of the window, albeit at different speeds. For example, even when the same voltage is applied to electrodes in two different areas, they will result in different transparency states, e.g., different transmission levels, due to different electrode patterns. For example, the curve representing transmittance versus voltage may be shifted. For example, if voltage control is changed in the same way in both areas, the light transmittance in both areas may change, but by different amounts. Areas may be made less responsive to the drive signal by reducing the density of electrodes, and in particular, areas may be made not to switch at all, for example, by not applying electrodes within the area.

[0133] For example, electrode materials may include copper, aluminum, gold, and indium-tin oxide (ITO). ITO is transparent, while Cu / Al is reflective; therefore, different electrode materials may be used to obtain different appearances, regardless of the driving voltage. Similarly, different materials with different resistances will produce different electric fields. For example, ITO will have a smaller electric field even when driven by the same voltage.

[0134] An embodiment of the method for modulating light includes applying a potential to a plurality of drive electrodes applied to two opposing substrates, according to an embodiment that obtains an electromagnetic field between the plurality of drive electrodes, thereby providing electrophoretic movement of particles toward or from one of the plurality of drive electrodes, resulting in modulation of light shining through the substrates, the two opposing substrates being the same as in one embodiment.

[0135] An optical modulator comprising a first substrate according to one embodiment is disclosed herein. For example, the first substrate may be transparent and have a driving electrode and a patterning element applied thereto. The driving electrode may be configured for controlling the electrophoresis and / or dielectrophoresis of particles in the optical layer of the optical modulator.

[0136] The optical modulator may include a second substrate. The second substrate may have patterned elements or may be a conventional substrate without patterned elements. Having patterned elements in at least one substrate, for example, within the first substrate, provides control over optical diffraction and is an improvement over known optical modulators. Having two substrates, for example, a first substrate and a second substrate, having optically active elements, provides even further control.

[0137] In one embodiment, the second substrate may be non-transparent, for example, opaque. For example, such an embodiment may be used for a dynamic mirror or an e-reading system. Typically, both the first and second substrates are transparent, particularly in smart glazing applications.

[0138] Figure 5a schematically shows an example of one embodiment of the optical modulator 501. The optical modulator 501 comprises 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. Within the optical layer 524 are particles 523 that affect the optical appearance of the optical modulator. At least one drive electrode 521 is applied to the first substrate 511. The optical properties of the optical modulator can be modified by applying a potential to at least one drive electrode 521. In the example shown, at least one drive electrode 522 is also applied to the second substrate 512.

[0139] The optical modulator is shown with particles aligned to the electrodes. This typically corresponds to the most transparent state of the optical modulator. In another state of the optical modulator, particles can be dispersed through the optical layer 524. This typically corresponds to the least transparent state of the optical modulator. Depending on the properties of the particles, this could be, for example, an opaque state that absorbs light, or it could be, for example, a reflective state that reflects light.

[0140] The surface of substrate 511 or substrate 512 facing the optical layer 524 is called the first surface.

[0141] At least one drive electrode 521 is arranged in a pattern across the substrate 511. At least one electrode 521 is positioned to receive a potential, resulting in modulation of the optical properties of the optical modulator. At least one drive electrode 522 is arranged in a pattern across the substrate 512. At least one electrode 522 is positioned to receive a potential, resulting in modulation of the optical properties of the optical modulator.

[0142] In a preferred optical modulator, for example, in a preferred implementation embodiment of the optical modulator shown in Figure 5a, at least two drive electrodes are applied to a first substrate 511, and at least two drive electrodes are applied to a second substrate 512. In this preferred optical modulator, particles 523 in the optical layer 524 are charged and movable under electrophoretic force which can be modified by electrodes on the substrate.

[0143] The patterning element 541 is applied to the surface of the substrate 511 and alters the phase, amplitude, and / or polarization of light interacting with the substrate. That is, the surface of the substrate 511 is configured to have optical properties that transform the substrate into a so-called metasurface. In this case, the patterning element 541 is applied to a second surface of the substrate 511, for example, a surface opposite to the surface supporting at least one electrode 521. For example, the patterning element may be an optical element with a diameter of less than 1 micrometer parallel to the substrate. Patterning is the process of creating micro and / or nanostructures across the surface of a material called a substrate.

[0144] The patterning element 542 is applied to the surface of the substrate 512 and alters the phase, amplitude, and / or polarization of the light interacting with the substrate. That is, similarly, the substrate 512 is provided with a metasurface. In this case, the patterning element 542 is applied to a second surface of the substrate 512, for example, a surface opposite to the surface supporting at least one electrode 522. Having the patterning element 542 on the second substrate is not necessary, but it is advantageous as it provides greater control.

[0145] Micro and / or nanopatterning is a process for creating nanostructures across the surface of a material called a substrate.

[0146] The optical modulator 501 further shows spacers 531. The spacers ensure that the optical modulators remain at a desired distance from each other. For example, the spacers may be manufactured from the same material as the substrate, and several spacers may be distributed across the substrate. Spacers are optional, and instead of spacers, for example, a boundary can be placed around the substrate to keep the substrates at a specific desired distance.

[0147] For example, the advantage of placing nanoparticles on a second surface of the substrate, rather than on the same side as the surface with the driving electrodes, is that the distribution of optical elements does not interfere with the photoelectrodes, and vice versa.

[0148] Figure 5b schematically shows an example of one embodiment of the optical modulator 502. The optical modulator 502 is similar to the optical modulator 501, except that the patterning elements are located on the same side as the drive electrodes in this example. Figure 5b shows the patterning elements 543 on the first surface of the substrate 511. Figure 5b shows the patterning elements 544 on the first surface of the substrate 512.

[0149] Having the patterned element on the same side as the surface allows the patterned element to face the optical layer. This protects the patterned element from damage, such as wear.

[0150] 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 manner.

[0151] Figure 5c schematically shows an example of one embodiment of an optical modulator. The optical modulator shown in Figure 5c is the same as the optical modulator in Figure 5b, except that the position of the particles in the optical layer has been changed. This may be done by applying a control signal to a driving electrode applied to an electrode on a substrate (or more). Note that as a result, the optical effect of the patterned element may change. There are various ways to deal with this. The first option is to accept this effect. In this case, the patterned element may be optimized for the average case and / or for commonly occurring conditions, e.g., to be as transparent as possible, or as opaque as possible. The second option is to modify these effects by applying a control signal to the patterned element as well, e.g., to create a canceling effect within the patterned element.

[0152] Figure 6a schematically shows an example of one embodiment of a transparent substrate 601 for use in an optical modulator, such as optical modulator 501, optical modulator 502, or any other optical modulator according to one embodiment.

[0153] The substrate 601 schematically shows two driving electrodes: driving electrode 611 and driving electrode 612. The two driving electrodes are arranged in an interlocking pattern. Thus, local control over the electric field, and therefore local control over the electrophoretic movement of particles, can be exercised across the substrate. Metasurfaces are also applicable in other types of optical modulators.

[0154] Figure 6a shows the patterned elements. The patterned elements are arranged in a pattern across the substrate according to a specific optical effect desired. Figure 6a also shows a vertical section line 631. Optical modulators 501 and 502 may be considered as cross-sections along line 631. Note that spacer 531 is not shown in Figure 6a.

[0155] For example, the patterned elements shown in Figures 6a, 5a, 5b, and elsewhere are two- or three-dimensional objects with nanometric geometric shapes. Typically, the patterned elements protrude from the surface. The shape and distribution of the patterned elements alter the optical properties of the substrate. This is sometimes called a metasurface. The optical properties of a metasurface can be calculated using optical simulation software.

[0156] The patterned elements on the substrate may have multiple different sizes, different shapes, and / or different materials. For example, the patterned elements may be obtained by shifting a two-dimensional shape away from the substrate surface parallel to the substrate to become three-dimensional. For example, the two-dimensional shape may be polygonal, circular, elliptical, and similar. The shape of the patterned elements may vary in three dimensions. The patterned elements may be cylindrical, elongated, and / or curved.

[0157] The patterned elements may extend from the surface and have a height of less than 1000 nanometers, preferably between 100 nanometers and 1000 nanometers, for example, a height of 600 nanometers.

[0158] For example, an optical modulator may be configured for use within a defined spectral range, such as visible light. The patterning element may be transparent within the defined spectral range, for example, transparent to visible light. The spectral range for visible light may be defined as 400-750 nm. The patterning element may be used to configure the spectral characteristics of the optical modulator.

[0159] The patterned element may have total transmittance within a defined spectral range greater than a threshold, for example, at least 70% or at least 80%. The total transmittance of the patterned element may be within the range [x-5, x+5], where x is the total transmittance of the substrate.

[0160] Interestingly, the patterned element does not need to be transparent. In one embodiment, the patterned element has total transmittance within a spectral range of at most 10%.

[0161] The spectral range may include infrared light having wavelengths between, for example, 750 nanometers and 1000 or 1500 nanometers. The spectral range may also include visible and infrared light having wavelengths between, for example, 400 nanometers and 1000 or 1500 nanometers.

[0162] Patterning elements are placed in the path of light passing through the substrate and optical layer. Since the patterning elements optically affect the light, they influence the optical properties of the optical modulator. Therefore, the optical properties of the optical modulator can be modified by shaping and / or configuring the pattern of the patterning elements. For example, patterning elements can alter the wavefront of light reflected from or transmitted through the substrate.

[0163] Figure 6b schematically shows an example of one embodiment of a transparent substrate 602 for use in an optical modulator. The diagram in Figure 6b is from above. In Figure 6b, patterned elements are visible, one of which has reference numeral 622. Figure 6b follows a constant proportional scale, with a virtual scale of 1 micrometer indicated by reference numeral 632. The shown patterned elements may be embodied in a transparent cylinder. A top circular view of the cylindrical pattern is seen in Figure 6b. The pattern shown in Figure 6b is detailed, and in one embodiment, the pattern extends across the substrate. Further details regarding the cylindrical pattern may 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, along with information on size and bandwidth.

[0164] Instead of a cylinder, the patterning element may have various other shapes. For example, the top view of the patterning element may 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 describes a generalized version of Snell's law that enables better control of optical manipulation. A metasurface may be designed such that the theoretical predictions given by the generalized Snell's law agree well with experimental data.

[0165] Metasurfaces may be fabricated using various CMOS fabrication techniques. The paper "Large-area metasurface on CMOS-compatible fabrication platform: driving flat optics from lab to fab," included herein by reference, discusses large-area, mass-producible, and low-cost metasurfaces that can be fabricated using commonly used semiconductor techniques, for example, by lithography steppers and scanners.

[0166] Examples of methods for manufacturing metasurfaces are 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 the said paper shows the fabrication process for a dielectric metasurface.

[0167] Figure 6c.1 schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. Figure 6c.2 schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. Figure 6c.1 shows a side view. Figure 6c.1 shows a top view of the same configuration as shown in Figure 6c.1. The figure shows a substrate having two of the patterned elements.

[0168] A patterned element has a 2D diameter, defined as the maximum diameter in a two-dimensional cross-section parallel to the substrate of the nanoelement. For example, the 2D diameter is the longest distance between any two points on the patterned element, and the two points are limited to being in the same plane parallel to the substrate. The 2D diameter is shown in the figure with reference number 662.

[0169] A patterned element has a height defined as the maximum extension of the patterned element from the substrate, measured perpendicular to the substrate. The heights of two patterned elements are indicated by reference digit 661. Furthermore, the distance to the next nearest element is indicated by digit 663.

[0170] In one embodiment, the 2D diameter, height, and nearest distance are related to the target frequency at which the patterning element is active.

[0171] 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.

[0172] 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.

[0173] A patterned element may have a longer dimension if another dimension is shorter. For example, in one embodiment, a patterned element has at least two discontinuous edges, and the shortest distance between two points on each discontinuous edge is at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers. For example, a patterned element may be a polygon, for example, a rectangle. A rectangle may have short edges, for example, less than the indicated range, while other edges may be long, for example, longer than 2 microns.

[0174] For example, in one embodiment, the patterned element extends in at least two directions. For example, the two directions may form an angle between 30 and 150 degrees, between 60 and 120 degrees, for example, about 90 degrees. For each direction, the longest distance, for example, the longest distance between two points on the same patterned element, may be identified. 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 nanoelement may be an ellipse that is longer than it is wide.

[0175] In one embodiment, the size of the patterned elements or the distance between them may vary. For example, in one embodiment, different optical effects may be desired at different locations on the optical modulator. For instance, in signage, a holographic effect may be desired not everywhere, but only in a portion of the optical modulator. Therefore, small and large patterned elements, and small or large distances between objects, may be mixed within the optical modulator.

[0176] 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.

[0177] In one embodiment, the 2D diameter, height, and nearest distance are all at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers.

[0178] The height of the patterned elements may be uniform; for example, a patterned element may have a flat top parallel to the substrate. The left patterned element in Figure 6c.1 has a uniform height. The height of the patterned elements may be uniform across the substrate; for example, all patterned elements may have the same height. The two patterned elements in Figure 6c.1 have the same height.

[0179] The height of the patterned element is typically much smaller than the height of the substrate, e.g., its thickness, although the patterned element may also be applied to thinner substrates. For example, in one embodiment, the substrate has a thickness of 10 microns or more, while the patterned element has a height of, for example, less than 1 micron. For example, the substrate may be a plastic film. The thickness of the substrate may be at least 10 times the height of the patterned element. The ratio is, however, typically higher. In one embodiment, the thickness of the substrate may be, for example, at least 100 times or at least 1000 times the height of the patterned element.

[0180] Figures 6d.1 and 6d.2 show the function of the metasurface in relation to the optical modulator.

[0181] Figure 6d.1 schematically shows an example of an optical modulator 643 without a patterning element.

[0182] The primary wavefront 642 incident on the optical modulator is shown. For example, the optical modulator may be smart glass, and the primary wavefront 642 may come from ambient light, such as sunlight. The optical modulator 643, shown only schematically, may be of the type shown in Figures 4a-4c and 5a-5b, but without the patterning element that creates a metasurface on the optical modulator. A cross-section of the driving electrodes arranged in a pattern on the substrate is shown for the optical modulator 643, in which case the electrodes are arranged on both substrates.

[0183] The electrode pattern has a distortion effect on the wavefront after the wavefront passes through the optical modulator 643. The distorted wavefront 644 is shown in Figure 6d.1. The distortion is visible in optical artifacts such as the rainbow effect and diffraction. The distortion can also be calculated, for example, using generalized Snell's law.

[0184] Figure 6d.2 schematically shows an example of one embodiment of an optical modulator 653 having a patterned element. The optical modulator in Figure 6d.2 is the same as the optical modulator in Figure 6d.1, except that it includes a patterned element that forms a metasurface according to one embodiment.

[0185] The primary wavefront 642 incident on the optical modulator is shown. The optical modulator 644 uses the same driving electrodes as in Figure 6d.1, but includes a patterning element extending across the substrate to form a metasurface on the optical modulator. One patterning element is indicated by reference numeral 655. In this example, the patterning element is applied to one side of each substrate, in this case the side facing the optical layer of the optical modulator 653. As shown herein, the metasurface may be formed on the side facing away from the optical layer, or similarly, and the metasurface may be formed on only one substrate or on three or more substrates.

[0186] In addition to the influence of the driving electrode, the nanopatterned element has an effect on the wavefront. The element may be selected to correct the wavefront, and Figure 6d.2 shows the corrected wavefront 654.

[0187] The pattern elements were selected using a computerized selection algorithm. The algorithm calculates the effect on the first wavefront 642 based on the combination of the driving electrode and the pattern elements. The location and / or shape of the pattern elements are modified over multiple iterations to minimize a loss function that includes one or more loss terms.

[0188] The loss term used in this case includes a distance term between the outgoing wavefront and the normal principal incident wavefront. That is, all optical changes in the wavefront are minimized. For example, the minimization may be for a specific optical frequency, or for multiple frequencies representing, for example, visible sunlight. For example, the minimization may be for various angles of light. The severity of optical artifacts may depend on the properties of the light, such as its direction and frequency(s). A design that works well overall may be selected by simulating a range of conditions.

[0189] Therefore, multiple candidate designs may be simulated under a range of conditions, for example, different lighting conditions. The design is selected from the multiple candidate designs that have a preferred simulation result, for example, the lowest mean loss across the conditions.

[0190] Any additional or alternative loss terms that may be used directly assess the severity of known artifacts, such as the rainbow effect and diffraction. Minimizing these loss terms allows the optical modulator to have an effect on the light, but the distracting element is reduced. Optimization may be performed using hill-climbing techniques such as simulated annealing.

[0191] To reduce computation time, in one embodiment, the pattern of the patterned element forming the metasurface may be optimized for small areas, such as building blocks, and this may be repeated across the substrate.

[0192] To reduce computation time, in one embodiment, the patterned elements are selected from a predetermined set, for example, using a set of cylindrical or inverted V-shaped (chevron-shaped) elements of a limited number of sizes. Optimizing the metasurface can now be simplified to selecting from a limited number of sizes and element locations. Thus, optimization does not need to consider the entire range of possible sizes. Further reductions in computation time may be achieved by restricting the element locations to a predetermined grid. Further reductions in computation time may be achieved by restricting the possible rotations of the elements to a limited number of predetermined sizes. The latter optimization is not applicable to rotationally symmetric elements, such as cylinders, but can be used for polygonal shapes, such as inverted V-shaped elements.

[0193] Optimization may involve optimizing the electrode placement along with the patterning elements. In this case, the loss term may include losses specific to the electrodes, such as how well the optical modulator works, e.g., the speed and uniformity of state transitions.

[0194] In Figure 6d.2, the optimization aims to reduce the influence of the electrodes on the wavefront. However, this is not necessary, and the optimization may instead aim to introduce any desired modification to the wavefront. For example, in one embodiment, the patterning element is configured to modify the wavefront 642 of the light passing through the substrate to generate a holographic image.

[0195] Patterned elements, e.g., subwavelength-scale geometric structures, can be tuned to produce a wide range of optical functions. Topology optimization may be used, for example, with freeform metasurfaces, to create a pattern of a patterned element that gives a desired optical response. For example, topology optimization may use a local gradient-based optimizer, for example, using the adjoint variables method. The local gradient-based topology optimizer obtains an initial device design to approach the desired optical response and then iteratively improves it through perturbations, e.g., small changes to the geometric layout of the metasurface and / or patterned element. Advantageously, the perturbations may be obtained using the adjoint variables method. This approach enables the creation of advanced metasurfaces with capabilities exceeding those of existing design methods.

[0196] For example, gradient-based optimization may use the adjoint variable method. In this approach, 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 minor adjustments to the design to improve the system's performance. The objective function may include strain parameters, e.g., diffraction and rainbowing, uniformity, and possibly a target grayscale. The optimization may be combined with one or more particle distributions, such as those produced by driving electrodes, as shown in Figures 5a–5c.

[0197] Topological optimization is further discussed in J. Fan's "Metagrating Topology Optimization," which is incorporated by reference.

[0198] Patterns on patterned elements, such as metasurfaces, may be used for various purposes. A key application is to compensate for the optical effects of electrodes. Like patterned elements, driving electrodes also affect the optical effects of optical modulators. Patterned elements can compensate for optical aberrations generated by the driving electrodes, for example, by creating the opposite optical effect compared to the optical effect created by the driving electrodes of the modulator. For example, a common problem with the type of substrate 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-2f undergo diffraction to different degrees. For example, pattern 2f has much better properties in this respect than, for example, the pattern in Figure 2b. Nevertheless, in both cases, adding patterned elements helps to reduce the rainbow effect.

[0199] Patterning elements can be configured to compensate for various optical artifacts of an optical modulator. Optical artifacts can be one or more of the following groups: diffraction, refraction, scattering, and perturbation of light as it passes through or reflects from the substrate. The diffraction effect induced by the driving electrode can be reduced by arranging the patterning elements to create equal but opposite distortions.

[0200] In one embodiment, the patterned element is configured to reduce, for example, minimize, light reflection. Thus, the opaque state of the optical modulator appears as a deeper black because the reflection is reduced.

[0201] In one embodiment, the patterning element is configured to focus incident light into the optical layer of the optical modulator. This reduces artifacts. For example, in an optical modulator comprising a first substrate and an optical layer and a second substrate, the patterning element on the first substrate and / or the second substrate may be positioned to focus incident light, for example, light incident on the first substrate and / or the second substrate from outside the optical modulator into the optical layer.

[0202] Patterned elements may provide optical wavelength control, filtering light passing through the substrate according to its wavelength. The optical effects provided by patterned elements may differ for light of different wavelengths. Patterned elements may provide optical polarization control, manipulating linear or circular polarization. For example, polarization may be affected by having a patterned element that is not rotationally symmetric. For instance, a rectangular, non-square object will affect polarization.

[0203] In one embodiment, the patterned element is fixed. For example, the element may be applied onto a substrate from a fixed material of a predetermined shape. For example, the element is passive. This is, however, not required. In one embodiment, the patterned element introduces optical distortion that depends on external factors, e.g., temperature, pressure, and / or electric field. For example, the patterned element may include a phase-change material. For example, the patterned element has a controllable shape. For example, U.S. Patent Application No. 2021333575(A1) (incorporated by reference) discloses a reversible phase-change material suitable for incorporation into a metalens.

[0204] For example, in one embodiment, the nanoelement may be electrically controlled and / or temperature-controlled, preferably independently of the electrodes. Preferably, the nanoelement may be controlled independently.

[0205] In one embodiment of an optical modulator, there is an interaction between the temperature of the optical modulator and the phase change of the metasurface caused by the temperature.

[0206] The temperature of the optical modulator may be modified by various means, such as heating elements, such as heating wires or microheating elements. The paper "Modeling and fabrication of Pt micro-heaters built on alumina Substrate" by Goran Miskovic describes a microheating element on a glass-coated substrate, which is incorporated herein by reference.

[0207] By changing the shape of the patterned element, superior control can be obtained compared to the method of wavefront modification by the optical modulator. For example, a patterned element having a changeable shape may be arranged in different shapes, for example, in the operational use of the optical modulator. This allows for changes in the phase, amplitude, and / or polarization of light interacting with the substrate, for example. For example, in one embodiment, the patterned element includes a phase-change material having optical distortion dependent on external factors, such as temperature, pressure, and / or electric field.

[0208] Figure 6e.1 schematically shows an example of an optical modulator having a conductive patterning element in an inactive state. Figure 6e.2 schematically shows an example of an optical modulator having a conductive patterning element in an active state. The substrates in these figures may be used, for example, as one of the substrates in an optical modulator of the type shown in any of the figures from Figures 3a to 5b, such as an electrophoretic optical modulator.

[0209] The patterned element is applied to a substrate shown from above in the plan view. The patterned element is shown as a rectangle. The patterned element is transparent, for example, transparent to visible light or transparent in the target spectrum. As a result, the patterned element has reduced optical effects; for example, the patterned element may form a metasurface, but the effect may be relatively small. In particular, the patterned element may have a refractive index close to that of the substrate to further reduce optical effects.

[0210] In one embodiment, a substrate, for example, a first substrate, is used in a light modulator configured such that particles can be aligned with patterning elements. This may be done by placing a driving electrode near or beneath the patterning elements, but a particularly advantageous way to do this is by using conductive patterning elements. The conductive patterning elements may be supplied with a potential so that particles can be moved toward the conductive patterning elements, for example, using electrophoretic force. For example, a second substrate may have conductive patterning elements aligned with the elements of the first substrate. For example, the elements of the second substrate may be arranged in a pattern that is mirrored with respect to the pattern on the first substrate.

[0211] By applying an electric potential to the conductive patterned element, charged particles align with the conductive patterned element. The effect is shown in Figure 6e.2. Previously, the patterned element was transparent and had a small optical modulation effect, but through the aligned particles, the transparency is reduced and the optical effect of the patterned element is increased. Thus, a metasurface is created, and its effect can be increased or decreased as desired.

[0212] Conductive patterning elements may be electrically controlled from the same driving electrodes used in the optical modulator to modulate light. Conductive patterning elements may be electrically controlled from driving electrodes specifically applied for conductive patterning elements.

[0213] Therefore, in one embodiment, the patterning element may be conductive and may be arranged to modulate particles, such as light-absorbing particles, such as particles that absorb light in a target spectrum, such as visible light. The optical properties of the patterning element are modulated. The patterning element may include ITO, for example, patches of ITO.

[0214] In one embodiment, all or some of the patterned elements on the substrate are transparent and electrically conductive patterned elements. For example, they may be transparent according to the absorption range targeted by the optical modulator and / or the substrate. For example, the optical 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.

[0215] Furthermore, the optical parameters of these patterned elements may be close to the optical parameters of the substrate, particularly the refractive index. For example, the patterned elements may have a refractive index within 10% of the refractive index of the substrate.

[0216] The conductive patterning element is configured to interact with particles in the optical layer of the optical modulator.

[0217] The patterning elements are configured to receive potentials and provide control over optical modulation in the optical modulator. For example, the patterning elements may be individually electrically addressable, for example, in a matrix addressing scheme. The patterning elements may be applied to the first surface in a regular grid covering at least a portion of the first surface, for example, in a regular grid as part of a matrix addressing scheme. Matrix addressing may use separate electrodes from the driving electrodes. For example, the optical modulator may be pixelated, with rows and columns addressing the patterning elements and, optionally, the driving electrodes. This allows for localized adaptation of optical effects and, optionally, transparency.

[0218] The optical modulator is configured to control the grayscale of the modulator by modulating the position of particles within the optical layer. This may be done by applying a control signal, such as an electrical control signal, to electrodes on a substrate. For example, in one embodiment, two substrates each have at least two electrodes, and charged particles in the optical layer between the two substrates can be controlled, thus obtaining a controllable grayscale. For example, the signal may be an AC signal.

[0219] In one embodiment, the optical effect of the patterned element may be modulated within an optical modulator. For example, the patterned element may be modulated by changing the temperature in a pattern that includes a phase-change material. For example, the patterned element may be conductive, and as a result, light-absorbing particles in the optical layer may accumulate near the patterned element.

[0220] The optical modulator may be configured to control itself 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 a desired grayscale level set within the modulator, for example, set by the user.

[0221] For example, the signal may be obtained in the calibration phase before the operation phase. For example, the optical modulator may be installed at its final destination, for example, in the form of smart glazing. A sensor, for example, a camera, may be positioned to observe the effect of the optical modulator. Sensor measurements may be used to modify the first and / or second control signals to reduce the occurrence of undesirable phenomena, such as diffraction and rainbowing. For example, in the calibration phase, the optical modulator may be driven over a range of the first and second control signals. Sensor measurements, for example, images, are recorded for various signals. From the sensor measurements, optical parameters, in particular, grayscale, for example, the transparency level of the optical modulator, and distortion values, for example, the observed amount of diffraction and / or rainbowing, are derived.

[0222] In one embodiment, information regarding the direction of incident light, such as sunlight, may be obtained from a GPS sensor, for example, as part of a satnav device. This is particularly useful in vehicles, such as those with smart glass. This information may be obtained dynamically during operational use.

[0223] In one embodiment, for example, information regarding the orientation of the glass may be obtained by applying a sensor to the glass during the calibration phase. The sensor may be fixed, for example, as part of a smart glass package, or it may be temporary. In particular, orientation information may be obtained by placing a smartphone in close contact with the glass. For example, an application on the smartphone may transfer the orientation information to the smart glass, for example, a controller of an optical modulator.

[0224] Directional information is useful because the control signals for patterning elements may depend on the current angle of light.

[0225] The algorithm may be applied to sensor values ​​and calibration control signals, for example, to derive a model about an optical modulator from sensor measurements, the model predicting the optical effect of the optical modulator and its current control signal. The model or algorithm may be computational, applying physical laws such as Snell's Law, but advantageously, it may instead be a machine learning model. For example, a neural network may be trained to predict the optical effect from the control signal and possibly other sensor values—the optical modulator may be equipped with sensors such as temperature and light sensors. From sensor values ​​showing the effect of a particular control signal, the algorithm learns which control signal to use to obtain a particular effect. After the calibration period, the camera may be removed. In one embodiment, the system may continue to learn and further optimize the model using, for example, user feedback or sensor measurements. Similarly, relatively slow changes in the environment will be automatically taken into account. The optical modulator may be manufactured independently of the environment in which it will ultimately be installed and operate, while still obtaining precise optical control. The control of the metasurface may depend on the angle and intensity of the incident light.

[0226] Therefore, the first and second control signals can be stored and / or derived when needed. Appropriate control signals can be derived based on current sensor values, such as current temperature and / or current light level or angle.

[0227] One embodiment of a method for calibrating an optical modulator includes the following: - Installing an optical modulator, for example, by installing an optical modulator. The optical modulator may be installed in a fixed location, for example, as smart glass in a building, for example, in an office. The optical modulator may be installed in a non-fixed location, for example, as smart glass in a vehicle, for example, inside a car. - Obtain information regarding the distortion and / or transparency of the optical modulator from an image sensor observing the optical modulator. For example, the image sensor may be a temporary image sensor installed to obtain information regarding the optical effects of the optical modulator. For example, the image sensor may be a camera installed in front of the optical modulator during the calibration phase. For example, the camera may be placed on a tripod. For example, the image sensor may be placed inside a room in a building where the glass is placed. For example, the image sensor may be placed inside a vehicle where the glass is placed. If the optical modulator is not fixed, it may be moved during the calibration phase or part thereof, for example, by driving the vehicle in which the optical modulator is installed, possibly while recording directional information. - To drive control signals for controlling the optical modulator during the operating phase.

[0228] During the calibration phase, multiple control signals may be applied to the drive electrodes and / or pattern elements. The image sensor may observe the effect. The effect may be summarized in distortion and transparency values, e.g., grayscale values. Control signals that provide a desired effect, e.g., specific transparency and low distortion, may be stored. New control signals may be derived from stored control signals, for example, by interpolation. A machine learning-capable model may be trained to predict the effect of the optical modulator from the control signals. Favorable control signals may be derived by trying multiple control signals in the trained model, for example, by selecting a control signal with desired parameters.

[0229] In one embodiment, the calibration method further includes obtaining information about the orientation of the optical modulator from an orientation sensor applied to the optical modulator. For example, the orientation sensor may be shared with a GPS device, such as a satnav device or a smartphone. The orientation sensor may be standalone. The orientation sensor may be temporary, for example, applied only during the calibration phase. In one embodiment, the optical modulator includes an orientation sensor.

[0230] The orientation sensor and image sensor may be configured to provide sensor data to the optical modulator controller, for example, measured values, and for example, image and / or orientation information.

[0231] After the calibration phase, the optical modulator may be controlled. Methods for controlling the optical modulator may include applying a potential to a driving electrode to modulate the electromagnetic field within the optical layer, thereby providing electrophoresis and / or dielectrophoresis of particles within the optical layer and modulating the light passing through the substrate. For example, the control signal applied to the driving electrode may be a control signal stored during the calibration phase. Patterning elements applied to the surface of the optical modulator can alter the phase, amplitude, and / or polarization of the light passing through the substrate.

[0232] The patterned elements may be passive, for example, they may not be configured to receive control signals. In one embodiment, the patterned elements are active, for example, configured to receive control signals and modulate their optical effects. For example, the patterned elements may include a phase-change material having optical distortions dependent on external factors, such as temperature, pressure, and / or electric fields, and the method includes modulating the external factors to modulate the optical distortions. The patterned elements may be conductive, and their optical effects may be configured to be modulated through particles selectively placed on top of the patterned elements. The control method may include modulating external factors, for example, applying control signals to modulate the optical distortions. The control signals may be stored in the calibration phase or derived from the calibration phase.

[0233] Patterned elements may be combined with coatings and applied to various surfaces of the substrate due to various advantages. Figures 7a–7g all show substrates for use in an optical modulator. The substrates in the figures assume that ambient light is above the figure and the optical layer is below the substrate. Only in Figure 7a is a surface configured to face the optical layer schematically indicated by reference numeral 712, while Figures 7b–7g have the same orientation. The lower substrate can be obtained from any of the figures in Figures 7a–7g by mirroring it along the horizontal axis.

[0234] Figure 7a schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. The figure shows the transparent substrate 711.

[0235] The substrate 711 has two surfaces, the first of which is configured to face the optical layer of the optical modulator, and this surface of the substrate is indicated by reference numeral 712.

[0236] Starting with substrate 711, a layer having patterned elements is applied to a first surface of substrate 711. One patterned element is indicated by reference numeral 745. The patterned elements are arranged to change the phase, amplitude, and / or polarization of light interacting with the substrate. The light interacting with the substrate includes light passing through the surface and / or light reflected from the surface. For example, the patterned elements may be arranged to form a metasurface.

[0237] In this example, the patterned elements are coated with coating 751 for patterned elements. Coatings used in optical modulators are typically transparent. Protective coating 751 prevents physical damage to the nanoelements.

[0238] The substrate 711 has at least one drive electrode applied to the substrate 711 on a first surface. One electrode has reference numeral 721. All of the electrodes shown may form part of a single connected electrode. In a preferred electrophoretic optical modulator, at least two mated electrodes are applied. The electrodes may be used to modulate the optical properties of the optical modulator.

[0239] In this example, starting with the substrate, the coating with patterned elements is applied following the pattern of the driving electrodes. In this example, the coating is not applied to the electrodes. In this configuration, the electrodes make fluid contact with the optical layer. In this configuration, the patterning of the nanoelements and electrodes can be determined independently of each other's locations.

[0240] Figure 7b schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. The substrate is the same as the substrate in Figure 7a, except that a coating 752 for the drive electrodes is applied in this example. In this configuration, the electrodes do not make direct fluidic contact with the optical layer. Both coatings 751 and 752 are typically nonconductive and transparent.

[0241] The protective coating 752 prevents direct contact between contaminants such as sand grains, fibers, pebbles, lumps, and particles present in the optical layer and within the electrodes. These contaminants can be formed in various ways, such as by aggregation of smaller particles, electrostatics, or trapping between electrodes. These contaminants may cause short circuits between electrodes on opposing substrates, between adjacent electrodes on the same substrate, and physical damage to the electrodes themselves, or any combination thereof. In one embodiment, the protective coating prevents both physical damage to the electrodes and short circuits between electrodes.

[0242] Figure 7c schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. The substrate is similar to the substrate in Figure 7a, except that both the nanoelements and electrodes are applied to the substrate in the same layer in this example. This configuration is thinner compared to, for example, Figure 7b. The selection of the location for the nanoelements here depends on the electrodes; for example, the nanoelements cannot be positioned where the electrodes are positioned. A combination coating 753 for the driving electrodes and patterning element coating is applied to both the nanoelements and the electrodes.

[0243] Figure 7d schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. In this example, the nanoelements and electrodes are applied to opposing surfaces of the substrate 711. The nanoelements are applied to a second surface of the substrate 711, oriented away from the optical layer. The electrodes are applied to a first surface of the substrate 711, oriented towards the optical layer.

[0244] In this example, coating 751 is applied to the patterned element, but no coating is applied to the electrodes.

[0245] Figure 7e schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. This substrate is similar to that in Figure 7d, except that the coating 752 for the drive electrodes is also applied to the first surface.

[0246] Figure 7f schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. In this example, the patterned elements are applied to both surfaces of the substrate. In Figure 7f, the first layer of nanoelements, the substrate 711, the second layer of nanoelements in coating 751, and the driving electrodes in coating 752 are shown in that order. In one embodiment, coating 751 is also applied to the second surface of the substrate.

[0247] Figure 7g schematically shows an example of one embodiment of a transparent substrate for use in an optical modulator. Figure 7g is similar to Figure 7f, except that the coating is not applied to the electrodes. Coating 751 may be further applied to a second surface, for example, to protect nanodevices.

[0248] In some embodiments, protective coatings, e.g., coatings 751, 752, and / or 753, provide the device with additional optical functions. In some embodiments, this is an independent optical function. In some embodiments, this is an optical function that works in conjunction with the electro-optical effect of the device. These can be, for example, reflective, anti-reflective, diffuse, and / or anti-diffraction effects for all wavelengths of light, or for parts 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 produce significant optical refraction. For example, a protective coating made of silicon nitride with an optical refractive index of 3 may be combined with a fluid solvent having an optical refractive index of less than 2. The refractive index difference will induce refraction of incident light, a change in the direction of light, according to Snell's law. The optical modulator can then direct the incident light in a specific direction designed for it. This effect, combined with the specific shape and topography of the patterned protective coating, can refract light in multiple directions and thus increase light diffusion or haze. Similarly, different protective coatings can be applied from the same substrate or different substrates to enhance specific light paths or diffusion.

[0249] For example, more information regarding coatings for protecting electrodes is referenced in PCT / EP2022 / 066713 of the same applicant, but similar coatings may be applied to nanodevices.

[0250] Depending on the selected material or combination of materials, the protective coating may be applied using various techniques known in this 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, slit coating, and combinations thereof.

[0251] Figure 8a schematically shows an example of one embodiment of the method 810 for manufacturing a substrate, similar to that of the first embodiment. Method 810 is - Provide a substrate 811, - Applying the drive electrodes to the first surface of the substrate 812, and arranging the substrate for the optical modulator 812, - Applying a patterned element to the surface of a substrate 813, including arranging a substrate having a metasurface, wherein the surface to which the patterned element is applied may be a first surface or a second surface of the substrate opposite to the first surface. Applying 812 and 813 may be performed simultaneously. Applying the patterned element 813 may be performed before applying 812.

[0252] Figure 8b schematically shows an example of one embodiment of method 820 for manufacturing an optical modulator, similar to that of one embodiment. Method 820 includes the following: - One embodiment provides, for example, a first substrate and a second substrate according to method 810 821. The second substrate may or may not have electrodes and / or patterned elements applied to the second substrate. - Applying an optical layer between the first substrate and the second substrate 822, - To seal the surfaces of the first substrate and the second substrate.

[0253] Figure 8c schematically shows an example of one embodiment of method 830 for operating the optical modulator, similar to that of one embodiment. Method 830 includes the following: - Applying an electric potential to the driving electrode 831 modulates the electromagnetic field within the optical layer, providing electrophoresis and / or dielectrophoresis of particles within the optical layer, and modulating the light passing through the substrate, 831, - Changing the phase, amplitude, and / or polarization of light passing through the substrate by a patterned element applied to the surface of the substrate 832.

[0254] The patterned element may optionally include a phase-change material having optical strain that depends on external factors, such as temperature, pressure, and / or electric field. Method 830 may optionally further include modulating the external factors to modulate the optical strain.

[0255] The following list of numbered clauses is an example, each contemplated. They are examples of embodiments.

[0256] substrate Clause 1. A transparent substrate for use in an optical modulator, - A micro and / or nano-patterned element is applied to the surface of a substrate, comprising at least one driving electrode (111-114, 121-124) applied to the first surface of the substrate, the driving electrode being arranged in a pattern across the substrate, the electrode being positioned to receive potential, resulting in modulation of the optical properties of the optical modulator, the micro and / or nano-patterned element being applied to the surface of the substrate, and changing the phase, amplitude, and / or polarization of light interacting with the substrate.

[0257] Article 2. - The patterned element has its maximum diameter in a two-dimensional cross-section parallel to the substrate of the nanoelement, and the diameter is at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers, and / or - The minimum distance between the two patterning elements is at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers, and / or - The substrate according to Clause 1, wherein the minimum distance between two patterned elements is at least 100 nanometers, 200 nanometers, or 400 nanometers.

[0258] Clause 3. The patterned element forms a metasurface, and the substrate according to Clause 1 or 2.

[0259] Clause 3.1. The patterned element on the substrate has a plurality of different sizes, different shapes, and / or different materials, and the substrate according to any one of Clauses 1 to 3.

[0260] Clause 4. The patterned element extends from the surface and has a height less than 1000 nanometers, preferably a height between 100 nanometers and 1000 nanometers, and the substrate according to any one of Clauses 1 to 3.1.

[0261] Clause 5. The patterned element is applied to the first substrate and / or the patterned element is applied to the second substrate facing the first substrate, and the substrate according to any one of Clauses 1 to 4.

[0262] Clause 6. The patterned element is configured to compensate for the optical artifacts of the optical modulator, and the substrate according to any one of Clauses 1 to 5.

[0263] Clause 7. The optical artifact is any one of light diffraction, refraction, light scattering, and perturbation when light passes through or is reflected from the substrate, and the substrate according to Clause 6.

[0264] Clause 8. The patterned element is configured to create an opposite diffraction effect compared to the diffraction effect created by the drive electrode of the modulator, and the substrate according to any one of Clauses 1 to 7.

[0265] Clause 9. The patterned element provides wavelength control of light passing through the substrate by filtering it according to wavelength, and the substrate according to any one of Clauses 1 to 8.

[0266] Clause 10. The patterned element changes the wavefront of light passing through the substrate and generates a holographic image, and the substrate according to any one of Clauses 1 to 9.

[0267] Clause 11. A substrate according to any one of Clauses 1 to 10, wherein the patterning element modifies the wavefront of light reflected through the substrate and compensates for optical aberrations generated by the driving electrode.

[0268] Clause 12. A substrate according to any one of Clauses 1 to 11, wherein the patterned element provides optical polarization control that manipulates linear or circular polarization.

[0269] Clause 12.1. A substrate according to any one of Clauses 1 to 12, wherein the patterned elements are passive, e.g., not controllable by external factors, or active, e.g., controllable by external factors.

[0270] Clause 13. A substrate according to any one of Clauses 1 to 12.1, including a controllable shape element configured to provide control over changes in the phase, amplitude, and / or polarization of light interacting with the substrate.

[0271] Clause 14. A substrate according to any one of Clauses 1 to 13, wherein the optical modulator is configured for use within a specified spectral range, and the patterning element has a total transmittance of at most 10% within the spectral range.

[0272] Clause 15. A substrate according to any one of Clauses 1 to 14, wherein the patterned element includes a phase-change material having optical distortion dependent on external factors, e.g., temperature, pressure, and / or electric field.

[0273] Clause 16. A substrate for use in an optical modulator as described in any one of Clauses 1 to 15, wherein the pattern of drive electrodes across the substrate comprises a plurality of repeating building blocks.

[0274] Article 15. - The building blocks are repeated across the substrate in at least two directions, and / or - A substrate according to any one of the clauses 1 to 16, wherein multiple different building blocks are repeated across the substrate in one or two directions.

[0275] Clause 16. At least one driving bus is arranged on the substrate for each driving electrode of at least one driving electrode to drive the driving electrode. - At least one driving bus is arranged on the surface of the substrate for each driving electrode to drive the driving electrode, and / or - The driving bus is only arranged on the surface of the substrate, and / or - The driving bus is arranged between building blocks covering the substrate. The substrate according to any one of Clauses 1 to 15.

[0276] Clause 17. The substrate according to any one of Clauses 1 to 16, wherein the substrate is non-rectangular.

[0277] Clause 18. A substrate for use in an optical modulator according to any one of Clauses 1 to 17, wherein at least one driving electrode comprises a plurality of driving electrodes. - The plurality of driving electrodes (111 - 114, 121 - 124) are interlocked with each other. Each of the plurality of driving electrodes is arranged in a pattern across the substrate. The plurality of interlocked driving electrodes are arranged alternately with respect to each other on the substrate. The pattern of the plurality of driving electrodes across the substrate comprises a plurality of repeating building blocks. Substrate.

[0278] Clause 19. The building block is - Comprising a plurality of interlocked electrodes extending in at least two directions across the building block. The interlocked electrodes within the building block form a driving electrode for at least one electrode within the plurality of interlocked electrodes within the building block. The maximum length between any two points on the electrode measured along the electrode within the building block is at least twice the length of the diagonal of the building block unit. Substrate for use in an optical modulator according to Clause 18.

[0279] Clause 20. At least one driving electrode comprises a plurality of driving electrodes. - The nearest distance from any point on the substrate to the first drive electrode and the nearest distance to the second drive electrode are less than a threshold, and / or - The sum of the nearest distance from any point on the substrate to the first drive electrode and the nearest distance to the second drive electrode is less than the first threshold and / or greater than the second threshold and / or - The distance from a point on the first drive electrode to a point on the second drive electrode is at least the second threshold, and / or - A substrate for use in an optical modulator as described in any one of Clauses 18 to 19, wherein the horizontal and / or vertical size of the building block is at least 10 times the sum of the electrode line width and the electrode distance.

[0280] 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, wherein an optical layer extends between the first substrate and the second substrate, and the optical properties of the optical modulator are modifiable by applying a potential to at least the driving electrode.

[0281] Article 22. An optical modulator, - A first substrate and a second substrate, wherein at least one of the first substrate and the second substrate is provided with a patterned element, for example, according to one embodiment, according to clauses 1 to 20, and at least one of the first substrate and the second substrate is arranged with their inner surfaces facing each other, the first substrate is transparent, and at least one driving electrode is applied to the inner surface of the first substrate, the driving electrode extends in a pattern across the inner surface of the first substrate and the second substrate. - An optical layer containing a fluid containing particles, disposed between a first substrate and a second substrate. - A controller configured to apply a potential to at least one driving electrode to obtain an electromagnetic field, provide the movement of particles toward or away from the driving electrode, and result in modulation of the optical properties of the optical modulator. An optical modulator equipped with the following features.

[0282] Clause 23. The optical modulator according to Clause 21 or 22, wherein at least one driving electrode comprises an ITO electrode.

[0283] Clause 24. An optical modulator as described in any one of Clauses 21 to 23, wherein the particles are charged or can be charged, and the controller is configured to apply a potential to a driving electrode to obtain an electromagnetic field, provide electrophoretic movement of the particles toward the driving electrode, and result in modulation of the optical properties of the optical modulator.

[0284] Clause 24.1. An optical modulator according to any one of Clauses 21 to 24, wherein a plurality of mutually mated drive electrodes are arranged across the inner surfaces of a first substrate and a second substrate, and a controller is configured to apply an electrical signal to the plurality of electrodes to obtain an electric field between the plurality of electrodes, provide electrophoretic transfer of particles, and result in modulation of the optical properties of the optical modulator.

[0285] Clause 24.2. Optical modulators, - By creating an alternating current voltage on at least one of the first substrate and the second substrate, and 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 substrate is switched to an opaque state. - An optical modulator according to any one of clauses 21 to 24.1, configured to switch to a transparent state by creating an alternating voltage between a first substrate and a second substrate and applying an alternating current between a first electrode on the first substrate and a first electrode on the second substrate, and / or between a second electrode on the first substrate and a second electrode on the second substrate.

[0286] Clause 24.3. Optical modulators as described in Clauses 21 to 24.2, wherein the electrical signal is an AC signal.

[0287] Clause 24.4. A light modulator as described in any one of Clauses 21 to 24.3, wherein the particles are charged or can be charged, and the particles move by electrophoretic force.

[0288] Clause 25. A light modulator as described in any one of Clauses 21 to 24.4, wherein the particles are charged or can be charged, and the particles move by electrophoretic force.

[0289] Clause 26. An optical modulator according to any one of Clauses 21 to 25, wherein the driving electrode is a line electrode, for example, the line electrode extends along a longitudinal direction and along a transverse direction, and the extension is at least 10 times, more preferably at least 100 times, longer in the longitudinal direction than the transverse extension in at least a local portion of the line electrode.

[0290] Article 27. - Transparent state and non-transparent state, and / or, - Having both a reflective state and a non-reflective state, An optical modulator according to any one of clauses 21 to 26, wherein the optical modulator is configured to switch between states by modulating a current between one or more drive electrodes applied on a first substrate and one or more drive electrodes optionally applied on a second substrate.

[0291] Article 28. - An electrical signal is provided as alternating current (AC) at one or more electrodes, or - An optical modulator according to any one of the clauses 21 to 27, wherein an electrical signal is provided as direct current (DC) at one or more electrodes, and the voltage is periodically inverted.

[0292] Clause 29. An optical modulator as described in any one of Clauses 21 to 28, wherein the first substrate and the second substrate are transparent.

[0293] Clause 30. An optical modulator according to any one of Clauses 21 to 29, 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.

[0294] Clause 31. One or more electrodes comprise multiple interlaced mesh electrodes, - An optical modulator according to any one of the clauses 21 to 30, wherein multiple interlaced mesh electrodes extend in a two-dimensional pattern across a first substrate and across a second substrate, and two of the multiple mesh electrodes on the substrate intersect at multiple intersections spread across the substrate.

[0295] Article 32. - The particles are nanoparticles and / or microparticles, and / or - The particles are configured to absorb light. - A light modulator according to any one of the clauses 21 to 31, wherein the particles are pigment particles.

[0296] Clause 33. An optical modulator according to any one of Clauses 21 to 32, wherein at least two electrodes include an electrically conductive material having a resistivity of less than 100 nΩm at 273 K.

[0297] Clause 34. An optical modulator according to any one of Clauses 21 to 33, wherein the electrode is in fluid contact with the fluid, or the electrode is separated from the fluid by, for example, a coating.

[0298] Clause 35. An optical modulator as described in any one of Clauses 21 to 34, wherein the electrodes applied to the substrate cover 1-30% of the substrate surface.

[0299] Clause 36. An optical modulator as described in any one of Clauses 21 to 35, wherein the potential operates at an AC frequency of 10–100 Hz to switch to a transparent state and / or at an AC frequency of less than 1 Hz to switch to a non-transparent state.

[0300] Clause 37. An optical modulator according to any one of Clauses 21 to 36, wherein the size of the nanoparticles is 10-1000 nm, preferably 100-500 nm.

[0301] Clause 38. An optical modulator according to any one of Clauses 21 to 37, wherein the particles are configured to absorb light having a wavelength of 10 nm to 1 micron.

[0302] Clause 39. An optical modulator according to any one of Clauses 21 to 38, wherein the distance between the first substrate and the second substrate is less than 500 μm.

[0303] Clause 40. An optical modulator as described in any one of Clauses 21 to 39, wherein the kinematic viscosity of the fluid is 500 mPa·s or less.

[0304] Clause 41. The fluid has a relative permittivity ε less than 100. r An optical modulator having any one of the clauses 21 to 40.

[0305] method Article 42. A method for modulating light, A method for modulating light, comprising applying a potential to one or more driving electrodes applied to one or two opposing substrates, thereby obtaining an electromagnetic field between the driving electrodes, providing electrophoretic movement of particles toward or from one of the plurality of driving electrodes, and resulting in modulation of light shining through the substrates, wherein at least one or both of the two opposing substrates are as described in any of the preceding paragraphs.

[0306] A method for modulating light as described in Clause 42, comprising using a two-phase alternating current having a potential between -220V and +220V and a current between -100μA and +100μA.

[0307] Clause 44. A temporary or non-temporary computer-readable medium containing data representing an instruction, wherein, when executed by a processor system, the instruction causes the processor system to perform the actions described in Clause 42 or 43.

[0308] Figure 9a shows a computer-readable medium 1000 having a writable portion 1010 containing a computer program 1020, and similarly, a computer-readable medium 1001 having a writable portion containing a computer program. The computer program 1020 includes, in one embodiment, instructions for 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 as a physical mark on the computer-readable medium 1000 or by magnetization of the computer-readable medium 1000. However, other suitable embodiments are conceivable. Furthermore, while the computer-readable medium 1000 is shown here as an optical disc, it will be recognized that the computer-readable medium 1000 may be any suitable computer-readable medium such as a hard disk, solid memory, flash memory, etc., and may be non-recordable or recordable. The computer program 1020 includes instructions for causing the processor system to perform the optical modulator method.

[0309] Figure 9b shows a schematic diagram of a processor system 1140 according to an embodiment of a controller for an optical modulator. The processor system comprises one or more integrated circuits 1110. The architecture of one or more integrated circuits 1110 is schematically shown in Figure 9b. Circuit 1110 includes a processing unit 1120, e.g., a CPU, for executing computer program components for performing the method according to the embodiment and / or implementing its module or unit. Circuit 1110 includes a memory 1122 for storing programming code, data, etc. Part of the memory 1122 may be read-only. Circuit 1110 may include communication elements 1126, e.g., an antenna, a connector, or both, and similar. Circuit 1110 may include a dedicated integrated circuit 1124 for performing some or all of the processing defined in the method. The processor 1120, memory 1122, dedicated IC 1124, and communication elements 1126 may be connected to each other via an interconnect 1130, e.g., a bus. The processor system 1110 may be configured for contact and / or contactless communication using antennas and / or connectors, respectively.

[0310] For example, in an embodiment, the processor system 1140, for example, the device, may comprise a processor circuit and a memory circuit, the processor being configured to execute software stored in the memory circuit. For example, the processor circuit may be an Intel Core i7 processor, an ARM Cortex-R8, etc. In an embodiment, the processor circuit may be an ARM Cortex-M0. The memory circuit may be a ROM circuit or non-volatile memory, such as flash memory. The memory circuit may be volatile memory, such as SRAM memory. In the latter case, the device may comprise a non-volatile software interface, such as a hard drive or a network interface, configured to provide software.

[0311] For example, a controller for an optical modulator that controls the voltage applied to an electrode may include a processor circuit, or similarly, or instead, a state machine.

[0312] It should be noted that the embodiments described above are illustrative rather than limiting to the subject matter disclosed herein, and that many alternative embodiments can be designed by those skilled in the art.

[0313] In a claim, no reference sign placed between parentheses shall be construed as limiting the claim. The use of the verb “comprise” and its conjugations shall not preclude the existence of elements or steps other than those stated in the claim. The article “a” or “an” preceding an element shall not preclude the existence of multiple such elements. Expressions such as “at least one of” preceding a list of elements shall represent a selection of all or any subset of the elements from the list. For example, the expression “at least one of A, B, and C” should be understood as including only A, only B, only C, both A and B, both A and C, both B and C, or all of A, B, and C. The subject matter disclosed herein may be implemented by hardware comprising several distinct elements and by a appropriately programmed computer. In a device claim enumerating several parts, some of these parts may be embodied by one of the same items of hardware. The mere fact that certain strategies are cited in different dependent claims does not indicate that combinations of these strategies cannot be used to one's advantage.

[0314] In the claims, references in parentheses refer to reference numerals or formulas of embodiments in the drawings illustrating embodiments, and thus enhance the understanding of the claims. These references shall not be construed as limiting the claims.

[0315] Explanation of Reference Numbers The following list of references and abbreviations is provided to facilitate the interpretation of the drawings and shall not be construed as limiting the claims. [Explanation of Symbols]

[0316] 10 Optical modulator 11. First substrate 12 Second substrate 13, 13a, 13b electrode 14, 14a, 14b electrode 15 Fluid 16 Controllers 30 particles 20 cars 21 Optical modulator 40 Optical modulators 41 First substrate 42 Second substrate 43 Third substrate 46 controllers 100-102 circuit board 111-114 Main line 121-124 Main Line 131-134 Mutually mated electrodes 140 Building Blocks 141-144 Building Blocks 110, 120 drive bus 110', 120' drive bus 119, 129 connection zones 191, 192 direction 203-204 circuit board 211-222 Building Blocks 251-262 Building Blocks 501, 502 Optical modulators 511, 512 Transparent substrate 521, 522 drive electrodes 523 particles 524 Optical layer 531 Spacer 541, 542, 543, 544 Patterned elements 601, 602 circuit boards 611,612 drive electrodes 621, 622 Patterned elements 631 Virtual Disconnection Line 632 virtual scale, 1 micrometer 642 First wavefront 643 Optical modulator 644 Distorted wavefront 645 Drive electrode 653 Optical modulator 654 Corrected wavefront 655 Patterned elements 661 Height 662 diameter 663 Distance between objects 711 Transparent substrate 712 Optical layer surface 721 Drive electrode 745, 746 Patterned Layers 751, 752, 753 Coating 1000, 1001 Computer-readable media 1010 Writable portion 1020 Computer Programs 1110 Integrated circuits (multiple possible) 1120 Processing Units 1122 memory 1124 Dedicated Integrated Circuit 1126 Communication elements 1130 Interconnect 1140 Processor System

Claims

1. A transparent substrate for use in an optical modulator, - A substrate comprising at least two driving electrodes (111-114, 121-124) applied to a first surface of the substrate, the at least two driving electrodes mating with each other, the driving electrodes arranged in a pattern across the substrate, the electrodes positioned to receive potentials and cause modulation of the optical properties of the optical modulator, nano and / or micropatterning elements applied to the surface of the substrate and changing the phase, amplitude, and / or polarization of light interacting with the substrate, the patterning elements positioned to compensate for optical artifacts of the optical modulator caused by the driving electrodes, the optical artifact being one of diffraction, refraction, light scattering, or perturbation of light as light passes through or is reflected from the substrate.

2. - The patterned element has its maximum diameter in a two-dimensional cross-section parallel to the substrate, and the diameter is 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, at most 500 nanometers, and / or - The minimum distance between the two patterned elements is at least 10 nanometers, at least 50 nanometers, at least 100 nanometers, 200 nanometers, or 400 nanometers. - The substrate according to claim 1, wherein the patterned element has at least two non-contiguous edges, and the shortest distance between two points on each non-contiguous edge is at most 2 micrometers, at most 1 micrometer, or at most 500 nanometers.

3. The substrate according to claim 1, wherein the patterned elements form a meta-surface.

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

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

6. The substrate according to claim 1, wherein the patterned elements are configured to produce a diffraction effect opposite to that produced by the driving electrodes of the optical modulator.

7. The substrate according to claim 1, wherein the patterned elements provide optical wavelength control by filtering light passing through the substrate according to its wavelength.

8. The substrate according to claim 1, wherein a patterning element changes the wavefront of light passing through the substrate to generate a holographic image.

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

10. The substrate according to claim 1, wherein the patterned elements provide optical polarization control that manipulates linear or circular polarization.

11. The substrate according to claim 1, comprising a patterned element having a controllable shape, configured to provide control over changes in the phase, amplitude, and / or polarization of light interacting with the substrate.

12. The substrate according to claim 1, wherein the optical modulator is configured for use within a defined spectral range including visible light and infrared light, and the patterning element has a total transmittance of at most 10% within a defined spectral range.

13. The substrate according to claim 1, wherein the patterned elements include a phase-change material having optical distortion dependent on temperature, pressure, and / or electric field.

14. The substrate according to claim 1, wherein the patterning elements on the substrate include transparent and electrically conductive patterning elements, and the patterning elements are configured to receive potential and provide control over optical modulation in the optical modulator.

15. The substrate according to claim 14, wherein the patterning element is configured to interact with particles in the optical layer of the optical modulator.

16. The substrate according to claim 14, wherein the patterned elements are individually electrically addressable.

17. The substrate according to claim 16, wherein the patterning element is applied to the first surface in a regular grid covering at least a portion of the first surface.

18. A method for manufacturing a substrate as described in claim 1, - To provide a circuit board, - Applying at least two drive electrodes to the first surface of the substrate, wherein at least two drive electrodes are mated to each other. - Applying patterned elements to the surface of a substrate. Methods that include...

19. An optical modulator comprising a first substrate as described 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 by applying a potential to at least one of at least two driving electrodes.

20. The optical modulator according to claim 19, wherein the optical layer comprises charged particles, the patterning element on the first substrate comprises a transparent, electrically conductive patterning element, and the optical modulator is configured to apply a potential to the conductive patterning element to align the charged particles to the conductive patterning element, and thus modulate the optical properties of the patterning element.

21. The optical modulator according to claim 19, wherein the patterning element is configured to focus light incident on the first substrate within the optical layer.

22. A method for calibrating an optical modulator according to claim 19, - To provide the aforementioned optical modulator, - Obtain information regarding the distortion and / or transparency of the optical modulator from an image sensor observing the optical modulator. - To derive control signals for controlling the optical modulator during the operating phase. Methods that include...

23. - Obtain information regarding the orientation of the optical modulator from the orientation sensor applied to the optical modulator. The method according to claim 22, further comprising:

24. A method for controlling an optical modulator, the optical modulator according to claim 19, comprising applying a potential to at least one of at least two driving electrodes to modulate an electromagnetic field in an optical layer, providing electrophoresis and / or dielectrophoresis of particles in the optical layer, and resulting in modulation of light passing through a substrate, wherein the phase, amplitude, and / or polarization of the light passing through the substrate are further modified by a patterning element applied to the surface of the substrate.

25. A method for controlling an optical modulator according to claim 24, wherein the patterning element comprises a phase-change material having optical distortion dependent on temperature, pressure, and / or an electric field, and / or the patterning element is conductive and has optical distortion dependent on an external factor including electric potential, the method comprising modulating the external factor to modulate the optical distortion.

26. A non-temporary computer-readable medium (1000) including data (1020) representing an instruction, wherein when the instruction is executed by the processor system, it causes the processor system to perform any one of the methods according to claims 22 to 25.

Images