Optical modulator, optical modulator method and smart glass

Abstract

Some embodiments relate to an optical modulator comprising a transparent substrate, or a transparent substrate and a reflective or partially reflective substrate, a plurality of electrodes applied to the substrate in a pattern across the substrate. A controller can apply an electric potential to the electrodes to obtain an electromagnetic field between the electrodes to provide electrophoretic movement of particles toward or away from the electrodes.

Description

Technical Field

[0001] The subject matter of this disclosure relates to an optical modulator, an optical modulator method, and a computer-readable medium. Background Technology

[0002] U.S. Patent Application No. 11 / 041579, Publication No. US20050185104 A1, entitled "Optically Active Glass," discloses known optically active glasses, which are incorporated herein by reference.

[0003] A known system comprises two parallel plates made of a transparent, reflective, or partially reflective material (such as glass or plastic). An internal volume defined between the plates is subdivided into multiple small, independent volumes or individual units, which are filled with a dielectric liquid. This liquid contains particulate suspensions of the dielectric material. The facing surfaces of the two plates carry electrodes facing each other. The electrodes are connected to a power source associated with a control device.

[0004] The electrodes of each plate are formed by pairs of interlaced comb-like structures. The electrodes of two interlaced comb-like structures can withstand voltages of the same or opposite polarities. With an appropriate voltage applied to the electrodes, particles can concentrate at different locations between the electrodes, giving the system a transparent or opaque appearance.

[0005] One known drawback of the system is that its optical state is unknown to the driver. This state can be approximated to some extent by tracking the duration of some driving signals applied, but this method is of low accuracy. Furthermore, if the panel is in a closed state, particularly for a period of time, then the panel's state is unknown. Summary of the Invention

[0006] An improved optical modulator would be advantageous. An optical modulator is provided, comprising at least one current sensing circuit connected to electrodes on a substrate. The current sensing circuit is configured to measure the current in the connected electrodes. A controller determines, at least from the current measured by the current sensing circuit, a drive signal for the electrodes to achieve or maintain a target transparency or target reflectivity. Interestingly, the position of charged or rechargeable particles in the optical modulator alters the optical properties of the modulator and the current in the electrodes. Information about the former can be obtained by measuring the current in the electrodes. In one embodiment, at least one current sensing circuit is provided, for example, for at least two electrodes (particularly adjacent electrodes) on the same substrate, or for two opposing electrodes on opposite substrates. In one embodiment, all electrodes have corresponding current sensing circuits.

[0007] For example, the current in the electrodes can be measured periodically to adapt the drive signal to changes in the transparency or reflectivity of the light modulator.

[0008] Light modulators are also known as optical modulators. They provide transparent or reflective panels whose transparency or reflectivity can be modified. In one embodiment, the color or color intensity can be altered. Light modulators can be used as lids, for example, for containers (e.g., closets, cabinets, etc.). A particularly advantageous application is in smart glazing. Smart glass is also known as smart windows.

[0009] In each embodiment, at least two electrodes are present on each substrate, but more than two electrodes may be present. For example, at least three electrodes may be applied to at least one of the first and second substrates. For example, in one embodiment, two electrodes may be applied to the first substrate and three electrodes may be applied to the second substrate. In one embodiment, at least three electrodes are applied to each substrate. At least two current sensing circuits may be applied to the at least three electrodes.

[0010] Systems with one substrate having at least two electrodes and another substrate having at least three electrodes offer various advantages. For example, light modulators can be driven to reduce the so-called curtain effect. The curtain effect occurs during window closure (i.e., moving to a dark, opaque, or blackout state), where it appears as if a curtain is drawn between the electrodes. The curtain effect is a disadvantage because it is noticeably distracting and also increases diffraction. Electrodes on the side with three electrodes can be closer together than on the side with two electrodes, for example, less than 50 micrometers, more preferably less than 40 micrometers, for example, 35 micrometers. This means a stronger electric field. Consequently, the closing speed is faster, and the curtain effect is reduced. Using a 2+2 electrode panel, moving the electrodes closer together will result in a decrease in maximum transparency or reflectivity, but this can be avoided when the additional electrodes are available. When open, some of the additional electrodes may be unused, so the loss of maximum transparency or reflectivity is minimal. Additional electrodes on the substrate (e.g., more than two electrodes) can be configured not to attract particles when the panel is open, but to attract particles when the panel is closed.

[0011] Another aspect of the invention is a building that includes a light modulator according to one embodiment. Another aspect of the invention is a vehicle that includes a light modulator according to one embodiment. For example, the vehicle and / or building may include a light modulator and a controller configured to control the transparency or reflectivity of the light modulator by controlling the voltage on the electrodes of the light modulator. The controller is electrically connected to or can be connected to the light modulator.

[0012] Light modulators and smart glass are electronic devices, for example, that can be powered by a power source under the control of a controller. For instance, the controller can instruct the power source to apply specific waveforms to specific electrodes to achieve various transparency or reflectivity effects, or the absence of these effects.

[0013] One embodiment of the method may be implemented on a computer as a computer-implemented method, or in dedicated hardware, or a combination of both. Executable code for one embodiment of the method may be stored on a computer program product. Embodiments of the computer program product include storage devices, optical storage devices, integrated circuits, servers, online software, etc. Preferably, the computer program product includes non-transitory program code stored on a computer-readable medium for executing one embodiment of the method when the program product is executed on a computer.

[0014] In one embodiment, the computer program includes computer program code that, when run on a computer, is adapted to perform all or part of the steps of one embodiment of the method. Preferably, the computer program is contained on a computer-readable medium. Attached Figure Description

[0015] Further details, aspects, and embodiments will be described with reference to the accompanying drawings by way of example only. Elements in the drawings are illustrated for simplicity and clarity and are not necessarily drawn to scale. In the drawings, elements corresponding to those already described may have the same reference numerals. In the drawings,

[0016] Figure 1 An embodiment of one implementation of an optical modulator is schematically illustrated;

[0017] Figure 2a An embodiment of one implementation of the substrate is illustrated schematically;

[0018] Figure 2b An embodiment of one implementation of the substrate is illustrated schematically;

[0019] Figure 3a An embodiment of one implementation of the controller is illustrated schematically;

[0020] Figure 3b An embodiment of one implementation of the controller is illustrated schematically;

[0021] Figure 4a An embodiment of one implementation of a current sensing circuit is schematically shown;

[0022] Figure 4bAn embodiment of one implementation of a current sensing circuit is schematically shown;

[0023] Figure 5a and Figure 5b An embodiment of one implementation of turning on the optical modulator is schematically shown;

[0024] Figure 6a and Figure 6b An embodiment of one implementation of turning off the optical modulator is schematically shown;

[0025] Figure 7 An embodiment of one implementation of controlling an optical modulator is schematically illustrated;

[0026] Figure 8 An embodiment of one implementation of controlling an optical modulator is schematically illustrated;

[0027] Figure 9a An embodiment of one implementation of an optical modulator is schematically illustrated;

[0028] Figure 9b An embodiment of one implementation of an optical modulator is schematically illustrated;

[0029] Figure 9c An embodiment of one implementation of a car is illustrated schematically;

[0030] Figures 10a to 10c An embodiment of an optical modulator is schematically illustrated;

[0031] Figure 11 An embodiment of one implementation of a method for controlling an optical modulator is schematically illustrated;

[0032] Figure 12a A computer-readable medium having a writable portion comprising a computer program according to one embodiment is illustrated schematically.

[0033] Figure 12b A representation of a processor system according to one embodiment is shown schematically.

[0034] Figure 1 , Figures 2a to 6b , Figures 9a to 10c , Figures 12a to 12b List of reference numerals in the attached figures

[0035] The following list of reference numerals and abbreviations is provided to facilitate the interpretation of the drawings and should not be construed as limiting the claims.

[0036] 10. Optical modulator

[0037] 11 First substrate

[0038] 12 Second substrate

[0039] Electrodes 13, 13a, and 13b

[0040] Electrodes 14, 14a, and 14b

[0041] 15. Fluid

[0042] 16 Controllers

[0043] 30 pieces

[0044] 20 cars

[0045] 21 Optical modulator

[0046] 40 Optical modulator

[0047] 41 First substrate

[0048] 42 Second substrate

[0049] 43 Third substrate

[0050] 46 Controller

[0051] 100 optical modulator

[0052] 101-104 electrodes

[0053] 111, 112 substrate

[0054] 113 Optical layer

[0055] 121-124 Drive circuit

[0056] 131-134 Current sensing circuit

[0057] 141-144 Current sensing signal circuit

[0058] 150 controller

[0059] 200 substrates

[0060] 201 First Direction

[0061] 202 Second Direction

[0062] 210 First Electrode

[0063] Main Line 211-213

[0064] 220 Second Electrode

[0065] Main Line 221-223

[0066] 310 Controller

[0067] 330 processor system

[0068] 340 storage

[0069] 350 interface

[0070] 361 Calibration Unit

[0071] 370 Control Unit

[0072] 371 Target Transparent Unit

[0073] 381 driver

[0074] 382 Current Sensing Interface

[0075] 383 sensor interface

[0076] 390 Optical Modulator Panel

[0077] 391 Sensors

[0078] 401 Resistor

[0079] 411 Current sensing circuit

[0080] 422 Current Signal

[0081] 431, 432 buffers

[0082] 440 Programmable Gain Amplifier

[0083] 441 Current signal

[0084] 442 Gain Signal

[0085] 511-514 Drive Signals

[0086] 611-614 Drive Signals

[0087] 1000 computer-readable media

[0088] 1010 writable portion

[0089] 1020 Computer Program

[0090] 1110 Integrated Circuits

[0091] 1120 Processing Unit

[0092] 1122 Memory

[0093] 1124 Application-Specific Integrated Circuit

[0094] 1126 Communication Components

[0095] 1130 Interconnect

[0096] 1140 Processor System Detailed Implementation Plan

[0097] While the subject matter of this disclosure allows for many different forms of implementation, one or more specific implementations are shown in the accompanying drawings and will be described in detail herein. It should be understood that this disclosure should be regarded as an exemplary principle of the subject matter of this disclosure and is not intended to limit it to the specific implementations shown and described.

[0098] In the following description, for ease of understanding, elements of the embodiments are described in operation. However, it will be apparent, however, that the corresponding elements are arranged to perform the functions described as being performed by them. Furthermore, the subject matter of this disclosure is not limited to the embodiments, but includes every other combination of features described herein or recited in mutually different dependent claims.

[0099] Figure 1 An embodiment of one implementation of the optical modulator 100 is schematically shown.

[0100] The optical modulator 100 includes a first substrate 111 and a second substrate 112. The first substrate and the second substrate are arranged so that their inner sides face each other.

[0101] Multiple electrodes are applied to the inner side of each of the first and second substrates. Electrodes 101 and 102 located on the inner side of substrate 111, and electrodes 103 and 104 located on the inner side of substrate 112 are shown in cross-section. Each of the multiple electrodes is arranged in a pattern spanning the substrates. An embodiment of this pattern is given below. Figure 1 In the diagram, two electrodes are shown on two substrates. An optical modulator can have more than two substrates, and each substrate can have more than two electrodes. Having more than two electrodes increases the switching speed and improves the driving of the optical modulator.

[0102] Typically, multi-electrode substrates are vertically aligned with one other multi-electrode substrate, but this is not mandatory. For example, offset placement can be used to reduce parallax effects. Additional substrates may be stacked above or below substrates 111 or 112.

[0103] Between substrates 111 and 112 is an optical layer 113. The optical layer comprises a fluid in which particles are suspended. The particles are charged or rechargeable and adapted to absorb or reflect light. The reflection can be diffuse or specular, or somewhere in between. If multiple optical layers are present, for example, using three or more substrates, the particles in the different layers may have different optical properties, such as absorbing or reflecting light at different wavelengths.

[0104] An electric potential (e.g., voltage) can be applied to the electrodes via a drive circuit. For example... Figure 1As shown: Electrodes 101-104 are electrically connected to drive lines 121-124, respectively. Drive lines 121-124 can be connected to a controller 150, which is configured to apply a specific voltage to the drive lines. The potential causes electrophoretic motion of the particles, which in turn affects the optical properties of the light modulator 100, such as its transparency or reflectivity.

[0105] Many parameters of an optical modulator can be modified to suit the needs of an application. For example, some applications require very dark, opaque solutions, while others require very transparent, non-dark solutions. Energy efficiency is important for some applications, but less so for others. Some applications require rapid switching, while others require high stability. These requirements can often be met, for example, by selecting appropriate fluid, particle, electrode, and substrate sizes. Driving such a wide variety of panels presents challenges, which are mitigated by current sensing. In one implementation, the hardware of a single controller design can be used for multiple panel types. Current measurement allows the controller to adapt the drive signal to the panel.

[0106] The optical modulator 100 includes at least one current sensing circuit connected to an electrode on a substrate. The current sensing circuit measures the current in the electrode to which it is connected. The amount of current passing through the electrode depends on the position of particles in the fluid relative to the electrode. Therefore, measuring the current in the electrode indicates the number of particles near that electrode. The position of the particles indicates the optical state of the optical modulator. Therefore, having only one circuit sensing circuit is preferable to having no circuit sensing circuit, but more circuit sensing circuits can be placed to obtain more information from the panel. Advantageously, for example, there are at least two circuit sensing signals in adjacent electrodes on the same substrate or in opposing electrodes on opposing substrates, because in this case, the current between the two electrodes can be calculated from the measured current. Even more preferably, as shown, the circuit sensing circuit is connected to each electrode of each substrate. Figure 1 As shown: Current sensing circuits 131-134 are respectively connected to drive lines 121-124. For example, the current sensing circuit may be part of a controller driving the optical module. The current sensing circuit may be part of one or more substrates. For example, the optical panel may include current sensing circuits between substrates (e.g., in the optical layer and electrically connected to electrodes).

[0107] A current sensing circuit generates a current sensing signal, which is transmitted to a controller 150 (e.g., via corresponding current sensing signal lines 141-144). The controller 150 is configured to receive at least one current sensing signal from at least one current sensing circuit. Figure 1As shown: Controller 150 is configured to receive current sensing signals from current sensing circuits 131-134. The current sensing circuits may be part of controller 150, in which case the current sensing signal lines may also be located within controller 150. The controller is configured to determine appropriate drive signals for the electrodes from at least the received current sensing signals. The drive signals may indicate potentials to be applied to multiple electrodes. For example, the potentials to be applied to multiple electrodes may include multiple potentials or a single potential.

[0108] A substrate (e.g., substrates 111-112), an optical layer (e.g., layer 113), electrodes (e.g., electrodes 101-104), and a portion of a possible driving circuit (e.g., lines 121-124) together constitute the panel portion of the optical modulator 100. The controller 150 may be integrated with the panel, but may also be connected to the panel via wires or the like.

[0109] Figure 2a An embodiment of one implementation of the substrate 200 is schematically shown. At least two electrodes are arranged in a pattern spanning the surface of the substrate 200. Figure 2a The diagram shows two electrodes on the same surface: a first electrode 210 and a second electrode 220. More than two electrodes may exist on the same side of the substrate, for example, to facilitate finer control. For example, multiple electrodes may be used to facilitate pixelation of the substrate (e.g., for a pixelated light modulator). An embodiment with two electrodes is shown below, but additional electrodes can be added, for example, by replicating a similar structure near each other.

[0110] The first electrode 210 and the second electrode 220 are applied to the same side of the substrate. These two electrodes are arranged in a pattern spanning the substrate. One, two, or more electrodes may also be present on the other surface of the substrate 200, for example, to facilitate the stacking of three or more substrates. Applying electrodes to the substrate can be accomplished by lithography (e.g., using a mask representing the electrode pattern). Electrodes can also be applied by embedding them into the substrate.

[0111] The first electrode 210 and the second electrode 220 each include multiple main circuits. For example... Figure 2aAs shown, the first electrode 210 includes main lines 211, 212, and 213, and the second electrode 220 includes main lines 221, 222, and 223. Typically, each electrode will include more than three lines. The main lines extend across the substrate. The multiple main lines of the first and second electrodes are arranged alternately relative to each other on the substrate. The main lines extend across the substrate in a first direction 201. When viewed in a second direction 202, the main lines from different multiples meet alternately, for example, a first multiple from the first electrode and a second multiple from the second electrode meet respectively. The first and second directions form an angle with each other, typically substantially perpendicular. The first and second directions may each be parallel to one side of the substrate, but this is not required.

[0112] An exciting application of substrates such as substrate 200 is in smart glass (e.g., light modulators), which can be used in homes, offices, greenhouses, automobiles, etc. The level of transparency or reflectivity of the smart glass can be electrically adapted. For example, in smart glass, two substrates such as substrate 200 are stacked such that the sides to which the two electrodes are applied face each other. A fluid containing particles is confined between the two substrates. In one embodiment, electrodes (e.g., two or more electrodes) are applied to one surface of each substrate. One, two, or more electrodes may also be present on the other surface of substrate 200, for example, to facilitate the stacking of three or more substrates.

[0113] Having two sets of alternating main circuits is sufficient to provide electrically adaptable glass; due to the alternating sets, the electric field at any part of the substrate can be controlled, as two opposing electrodes intersect the part from two opposing sides.

[0114] Figure 2b Two embodiments of an implementation of a substrate having an electrode pattern according to one embodiment are schematically shown. Figure 2b The embodiments shown are to scale and can be extended to (e.g., according to an interdigital pattern) a complete electrode pattern. As one example, Figure 2b This demonstrates how the basic patterns of multiple main lines can be extended using various features. For example, in Figure 2b In this process, branching patterns are connected to the main line. While such branching is not mandatory, it reduces diffraction. Another possible extension is to include waves within the main line.

[0115] Figure 2b An embodiment of one implementation of a substrate arranged for two or three electrodes is schematically shown. Figure 2b The letters 'a' and 'b' on the left indicate which main lines belong to the same electrode. All lines marked 'a' are electrically connected, although this is not explicitly stated in the original text. Figure 2b The details of the electrode pattern shown are not presented; similarly, the main circuit of 'b' is also not shown. Figure 2b The letters 'a', 'b', and 'c' on the right indicate which main circuits belong to the same electrode. All circuits marked with the same letter are electrically connected. Circuits marked with different letters are not electrically connected. Figure 5b The two substrates on the left can be combined to form a 2+2 electrode optical modulator. Figure 5b The two substrates on the right can be combined to form a 3+3 electrode optical modulator.

[0116] Figure 3a An embodiment of one implementation of the controller 310 is illustrated schematically. For example, Figure 3a The controller 310 can be used to control an optical modulator, for example, Figure 1 The optical modulator shown is illustrated. Controller 310 can be used with controller 150. Controller 310 may include processor system 330, storage 340, and communication interface 350. Storage 340 includes local memory, such as a local hard disk drive or electronic storage. Storage 340 may also include non-local storage, such as cloud storage. In the latter case, storage 340 may include a storage interface with the non-local storage.

[0117] Controller 310 (e.g., communication interface 350) is configured to communicate with an optical modulator for controlling the optical modulator. Communication with the optical modulator may include wires, for example, for driving panels and receiving sensor signals (including current sensing signals). In controller 310, communication interface 350 may be used to send or receive analog and / or digital data. For example, communication interface 350 may be configured for one or more of the following protocols: UART, SPI, I2C, CAN, etc.

[0118] For example, the drive and sensing signals can be analog. For example, the sensing signal can be digital, for example, converted to digital. The drive signal can be digital and converted to the actual voltage level locally at the optical modulator.

[0119] The controller 310 can communicate with other systems, external storage, input devices, output devices, and / or one or more sensors via a computer network. The computer network can be the Internet, an intranet, a LAN, a WLAN, etc. The controller includes a connectivity interface arranged to communicate externally as needed. For example, the connectivity interface can include connectors, such as wired connectors (e.g., Ethernet connectors, optical connectors, etc.) or wireless connectors (e.g., antennas, such as Wi-Fi, 4G, or 5G antennas).

[0120] The execution of controller 310 can be implemented in a processor system (e.g., one or more processor circuits, such as a microprocessor, one embodiment of which is shown herein). Controller 310 may include multiple processors that may be distributed in different locations. For example, controller 310 may use cloud computing. Controller 310 may also, or alternatively, include a state machine.

[0121] Figure 3b A functional unit is shown, which may be a functional unit of a processor system. For example, Figure 3b These can be used as blueprints for the possible functional organization of a processor system. In these diagrams, the processor circuitry is not shown separately from these units. For example, Figure 3b The functional units shown may be implemented, in whole or in part, by computer instructions stored at the controller 310 (e.g., in the electronic memory of the controller 310) and executable by the microprocessor of the controller 310. In a hybrid implementation, the functional units are implemented partly in hardware (e.g., as a coprocessor) and partly in software stored and executed on the controller 310.

[0122] Figure 3b An embodiment of one implementation of the controller 310 is schematically illustrated. The controller 310 is configured to control an optical modulator panel 390. The optical modulator panel 390 includes a plurality of substrates, each having a corresponding plurality of electrodes and at least one optical layer enclosed between the substrates.

[0123] The optical modulator panel 390 can be, for example, about Figure 1 or Figures 9a-9c The embodiments described above. One or more current sensing circuits may be included in the controller 310; alternatively, the current sensing circuits may be included in the optical modulator panel 390. Preferably, the optical modulator panel 390 or the controller 310 includes multiple current sensing circuits, for example, each electrode in the optical modulator panel 390 has a current sensing circuit. Figure 3b An optional sensor 391 that works in conjunction with panel 390 is also shown. Sensor 391 may include additional sensors, such as a temperature sensor or a light sensor, as further explained herein.

[0124] Controller 310 includes driver 381. Driver 381 is configured to apply a potential to electrodes on the substrate of light modulator panel 390 according to a drive signal to obtain an electromagnetic field between the electrodes. This electromagnetic field provides electrophoretic motion of particles in light modulator panel 390 toward or away from the electrodes. For example, the drive signal may be applied directly to the electrodes. For example, the drive signal may be indicative; for example, driver 381 may amplify the drive signal before applying it to the electrodes. Driver 381 may be connected to a power supply. Driver 381 may be local to panel 390 and not included in controller 310.

[0125] The controller 310 includes a current sensing interface 382 configured to receive at least one current sensing signal from at least one current sensing circuit, the at least one current sensing signal indicating the current in a connected electrode. For example, the current sensing interface 382 can receive current sensing signals from all electrodes on all substrates. For example, when the current interface 382 is connected to... Figure 1 In the illustrated optical modulator, current interface 382 can receive current sensing signals from electrodes 101-104. In one embodiment, the current sensing circuitry is integrated with driver 381, and interface 382 can receive current sensing signals from driver 381. The current sensing signals can be analog or digital; they can be converted from analog to digital, for example, at interface 382, ​​at the current sensing circuitry, etc.

[0126] Optionally, the controller 310 includes a sensor interface 383 configured to receive sensor signals from a sensor 391. The sensor 391 may be arranged on, within, or near a panel 390. Multiple sensors may be present.

[0127] Controller 310 may optionally include calibration unit 361. For example, panel 390 may be calibrated during manufacturing, or even another but similar panel may be calibrated. However, better results are obtained if calibration unit 361 is present in controller 310. One advantage of having calibration unit 361 in controller 310 is that recalibration can be performed locally. This is an advantage because the response of optical modulator panel 390 may change over time.

[0128] The calibration unit 361 is configured to determine the response of the light modulator panel 390 upon receiving a drive signal. For example, the calibration unit 361 can drive the panel 390 to a known state and measure the current in the electrodes in that known state. The known state can be obtained using a sensor 391; for example, a transparency sensor can be arranged on the panel 390 to measure the panel's transparency. However, in the absence of a transparency sensor, the known state can be obtained by applying a potential to the electrodes to drive the light modulator to its maximum or minimum transparency. After applying the potential for a time interval (e.g., a predetermined time interval selected to allow the panel 390 time to reach maximum or minimum transparency), a current sensing signal can be obtained from multiple current sensing circuits. Therefore, when the panel 390 is in a known state, the current in the electrodes can be obtained. Similarly, in another embodiment, a reflectivity sensor can be arranged on the panel 390 to measure the panel's reflectivity. After applying an electric potential for a time interval (e.g., a predetermined time interval, selected to allow the panel 390 time to reach maximum or minimum reflectivity), a current sensing signal can be obtained from multiple current sensing circuits.

[0129] During use, after calibration, the drive signal can be determined from the current sensing signal obtained during the use phase and the current sensing signal of the known state obtained during the early calibration phase, as well as from, for example, the target transparency or the target reflectivity.

[0130] When panel 390 is in a known state, the calibration value of the current in the electrodes can advantageously be obtained locally, for example, after panel 390 has been installed. For example, panel 390 could be smart glass in a building or vehicle. Significantly, calibration unit 361 allows for recalibration. For example, controller 310 can be configured to calibrate the light panel 390 under various conditions, such as when the light modulator is first turned on, when the light modulator is turned on after a threshold time has elapsed since it was turned off, when measuring a current that is out of range, or when the target transparency or target reflectivity level is not reached within a threshold time.

[0131] The controller 310 includes a control unit 370. The control unit 370 is configured to determine the drive signal of the electrode from at least one current sensing signal and from the target transparency or target reflectivity.

[0132] In one implementation, the drive signal indicates alternating current (AC) in the electrodes. The amplitude, frequency, or bias of the drive signal may differ for different operations; for example, the amplitude, frequency, or bias may differ when the panel 390 is closed, open, or being measured.

[0133] Typically, the drive signal will indicate alternating current. Although the drive signal may contain elements of DC bias, it is preferred to be balanced to avoid corrosion of the electrode material. For example, if panel 390 has been driven DC for a first time interval, it is preferably driven with the opposite polarity thereafter for a second time interval; the lengths of the first and second intervals, or the voltages applied during the time intervals, do not need to be the same. To avoid electrode corrosion, the length of the time intervals and the voltages applied during the time intervals are chosen such that the loss and gain of the electrode material are balanced. For example, in an exemplary embodiment, one might drive for a period of time, for example, with 1 volt DC; later, the voltage might be 0.6 volt DC with the opposite polarity and for different durations. Balancing the current with an AC drive signal is easier.

[0134] The control unit 370 can be configured to determine the transparency or reflectivity level of the light modulator from at least one current sensing signal. The current value between specific electrodes can be calculated from the current signal of each electrode, for example, as the difference between measured current values. The calculated current between the electrodes indicates the number of particles between them. If the particles are mostly between electrodes on the same substrate, the panel is opaque. If the particles are mostly between opposing electrodes on two substrates and both substrates are transparent, the panel is transparent. If the particles are mostly between opposing electrodes on two substrates and one of the substrates is reflective, the panel is reflective. If one of the substrates is partially reflective, an intermediate state can be obtained.

[0135] For example, consider the current measurements of electrodes 101-104 as I1, I2, I3, and I4. The state of the panel can be calculated as f(I1, I2, I3, I4, h), where f is a function and h is available additional information, such as temperature. In one embodiment, multiple functions f are calculated. i The latter can be used when certain functions have low precision for certain states, for example, when the function is close to zero, or when a particular function can be used to drive a specific state or range of states.

[0136] The current between electrodes 101 and 102 can be calculated as: I 12 =abs(I1-I2). The current between electrodes 101 and 103 can be calculated as: I 13 =abs(I1-I3). For example, the current between current groups can also be calculated as I. 12 and I 34 The sum of, or any other mathematical combination.

[0137] When the current between electrodes on the same substrate is high, for example, if I 12If the current is very high, the panel will be opaque. When the current between the electrodes on the substrate is very high, for example, if I... 13 The panel is highly reflective; if both substrates are transparent, the panel is transparent; if one of the substrates (e.g., the bottom substrate) is reflective, the panel is reflective. An intermediate state can be achieved if one of the substrates is partially reflective. Either value (e.g., I0) can be used. 12 Or I 13 This is used to determine the optical state of panel 390. There is an advantage to determining both simultaneously. When panel 390 is turned on (e.g., when driven to increase the transparency or reflectivity of panel 390, also known as vertical drive), one can primarily use I... 13 Because I 12 As the panel expands and becomes smaller, the precision decreases. Similarly, when driving the panel to reduce transparency or reflectivity (also known as horizontal driving), one can primarily use I... 12 .

[0138] Note that diagonal drive can also be performed, which will cause the particles to be centered. In this case, the current will be equal. Diagonal drive disperses the particles quickly and is a good method for closing panels. Diagonal drive can be used, for example, to close panels. The diagonal current can be calculated as I. 14 =abs(I1-I4). In one embodiment, diagonal driving is used in conjunction with vertical or lateral driving and electrode configuration, wherein the first substrate and the second substrate each include two electrodes. In one embodiment, diagonal driving is used in conjunction with electrode configuration, wherein at least three electrodes are applied to at least one of the first substrate and the second substrate.

[0139] The absolute value function (abs) facilitates the calculation of current, but it is not practically necessary when careful to measure current with the correct polarity. The current between current groups can also be calculated, for example, as I. 12 and I 34 The sum of, or any other mathematical combination.

[0140] Therefore, the state of panel 390 can be determined from the current between the electrodes, which in turn can be calculated from the current on the electrodes. The current between the electrodes depends on the position of charged particles in the optical layer (e.g., in a dielectric fluid), and the position of these particles directly affects the transparency or reflectivity level of the light modulator. An indication of the transparency or reflectivity state of panel 390 can be obtained by calculating the currents between the electrodes in the vertical, horizontal, diagonal, and / or combinations thereof. In the embodiment given above, the horizontal, vertical, and diagonal currents are calculated. However, any intermediate combination between these three directions can be used. When driving transparency or reflectivity towards a similar combination of electrode currents, it is advantageous to use a different electrode combination as the calculated current because this improves accuracy.

[0141] The calculated current between the electrodes can be directly used to calculate the drive signal. For example, the control unit 370 can drive the panel 390 to open, causing I... 13 Reaching a specific value. Later, it can be directed towards I again. 13 The same value is used to drive the panel. For example, this can be used to ensure that the same level of transparency or reflectivity is achieved on different days. In this case, the calibration value is not strictly necessary.

[0142] However, when calibration values ​​are available, one can calculate the current between the electrodes under known conditions, and the current in any intermediate state, and drive it towards them. Furthermore, calibration values ​​allow driving towards the same transparency or reflectivity in different situations, even if the panel's response has changed, for example, due to aging or temperature variations.

[0143] For example, one can calculate I during calibration for two known states (e.g., completely dark and completely transparent, or completely dark and completely reflective). 13 To achieve a specific intermediate level of transparency or reflectivity, such as x% transparency or reflectivity, one can direct the current value between the electrodes to x% of the calibrated value (e.g., I). 13 ) drive. If calibration is performed only for the fully transparent state, one can assume that for the fully closed state I 13 The value is 0, and the same applies to other values. However, it is preferable to calibrate using two known states.

[0144] In other words, during calibration, the minimum and maximum values ​​of the current between the two electrodes are obtained. During use, after calibration, the current between the electrodes can serve as an indicator of the panel's transparency or reflectivity. For example, entering a dark state corresponds to this specific low current, entering a transparent or reflective state corresponds to this high current, and so on. When driving towards an intermediate current, grayscale levels can be used. Target transparency or reflectivity (e.g., target percentage) can be translated into a target current between specific electrodes.

[0145] To establish a specific voltage or maximum amplitude for the AC signal, known dynamic feedback control algorithms can be used, such as closed-loop algorithms known from control theory. For example, the controller can repeat the following loop:

[0146] 1. By interpolating between calibration currents, the target transparency or target reflectivity is converted into the target current between electrodes;

[0147] 2. Apply a drive signal to the electrodes in panel 390 and maintain it for a time interval;

[0148] 3. Use a current sensing circuit to measure the current in the electrodes;

[0149] 4. Calculate the current between the electrodes, for example, the horizontal current and / or the vertical current;

[0150] 5. Compare the calculated current with the target current, modify the drive signal according to the dynamic feedback algorithm, and then proceed to step 2.

[0151] If the algorithm described above is applied to the current calculated from the calibration value, the algorithm will drive panel 390 toward the calibration state (e.g., fully transparent, fully reflective, or fully opaque). However, if the algorithm is applied to an intermediate current between calibration currents, the algorithm will drive panel 390 toward an intermediate state between calibration states (e.g., an intermediate state between fully transparent, fully reflective, or fully opaque).

[0152] The drive signal can vary along multiple dimensions. A typical choice is voltage (e.g., peak voltage), but other elements that can be changed, either additionally or alternatively, are the duty cycle, bias, waveform shape, or AC frequency. For example, using the duty cycle can be advantageous for reducing the power consumption of the device. Another embodiment is that the transition time between two intermediate device states can also be affected by using frequency. The drive can also include subsequent drives of multiple segments to generate subsequent electric field orientation.

[0153] In one implementation, the drive panel 390 typically applies different drive signals to different electrodes. Therefore, variations in electrode manufacturing must be taken into account. For example, given any three electrodes, the drive signals for them may be different.

[0154] In a variant of the algorithm described above, the electrode used to calculate the target current and drive it toward that target current is selected from the direction in which the panel is driven or may be driven. For example, using I... 13 Perform vertical drive using I 12Horizontal driving, and so on. One can even use a calculated current (say, I'), which is specific to a particular transparency or reflectivity. For example, panel 390 can first be driven towards the desired state using a known calibration state, after which I' can be calculated. In the future, the value of I' can be used for driving. The value of I' can be a linear combination of measured currents.

[0155] In one embodiment, more than two calibration states are used, for example, more states than just full darkness and full transparency or full reflection. This can be accomplished using a transparency sensor or a reflectivity sensor. For example, panel 390 can be driven to various states between full darkness and full transparency, where transparency can be measured by a transparency sensor and the current in the electrodes can be measured. Similarly, in another embodiment, panel 390 can be driven to various states between full darkness and full reflection, where reflectivity can be measured by a reflectivity sensor and the current in the electrodes can be measured. In one embodiment, a combination of a transparency sensor and a reflectivity sensor is applied. Therefore, even more precise actuation can be obtained. For example, one can calculate the current between the electrodes in the calibration state and drive towards the intermediate position during use, represented by the intermediate current.

[0156] The controller 310 may include a target transparency unit 371 configured to set a target transparency. For example, the target transparency may be set directly by the user, such as 75% gray. The target transparency is obtained from user input and / or from a sensor signal from a light sensor. For example, the target transparency may be calculated from a light sensor (e.g., an ambient light sensor, possibly in conjunction with an external light sensor). The light sensor may be in sensor 391; the light sensing signal may be received at interface 383. The target transparency may be expressed as, for example, a percentage between minimum and maximum transparency. The target transparency may be expressed as a target current. The light sensor is optional; for example, the target transparency may be obtained directly from user input, a schedule, etc.

[0157] If calibration is used, the light modulator can have two phases: a calibration phase and a usage phase. The calibration phase may include one or more cycles of driving and measuring current toward a known state; two or four cycles. The calibration phase may also include measuring sensor values. The usage phase may include multiple cycles with a driving section and a measuring section, in which the panel is driven toward a target transparency or target reflectivity in the driving section, and current and / or other sensor values ​​are measured in the measuring section. Instead of driving toward a target transparency or target reflectivity, the panel may remain at the target transparency or target reflectivity.

[0158] To accurately measure the current in the electrodes, the controller 310 (e.g., control unit 370 or drive unit 381) can temporarily drive all electrodes with a measurement signal. For example, the measurement signal can be the same for different measurement operations. For example, the measurement signal can be a constant signal, and can be the same for all electrodes, or at least for all electrodes connected to the same optical layer.

[0159] A measurement signal is applied during the measurement duration. A current sensing signal is received during this duration. When the measurement duration ends, normal panel operation can be resumed; for example, a potential can be applied to the electrodes according to a drive signal.

[0160] For example, the measurement signal can be an AC signal with certain specific maximum amplitudes. When the measurement signal is applied, multiple measurement samples can be obtained, for example, when the measurement signal is at its peak amplitude (e.g., peak maximum and / or peak minimum). In this way, multiple samples can be obtained, which can be averaged, summed, or any other mathematical combination to improve accuracy. As an exemplary embodiment, the AC signal might be 15 volts, with 10 samples taken at +15 volts and 10 samples taken at -15 volts. These numbers depend on the specific application and panel size, etc. The number of samples can be more or less, for example, 100 or more or less, the voltage can be different, and so on. In one embodiment, the potential is a constant AC signal, and all electrodes are simultaneously or continuously driven by the constant AC signal to evaluate the current of all electrodes during the measurement duration. In another embodiment, the potential is a varying AC signal, and all electrodes are simultaneously or continuously driven by the varying AC signal to evaluate the current of all electrodes during the measurement duration. The frequency of the measurement signal can be the same as the frequency used for driving, but this is not required. For example, one could take 100 Hz or 50 Hz, and so on. Similarly, these are all examples. Additionally, for the measurement signal, DC neutral is preferred to avoid corrosion.

[0161] During measurement, the position of the particles may change due to the voltage applied to the electrodes. This can be avoided by maintaining a short measurement duration and / or a low measurement amplitude. One advantage of measuring at a relatively high frequency is that multiple samples can be obtained in a short period of time. For example, fewer than 50 samples can be measured at a time; for example, the measurement frequency can be at least 50 Hz.

[0162] The peak amplitude during measurement may be lower than during drive. As an example, the measurement voltage could be 10 volts, while the drive voltage could be 20 volts. However, these are merely example values ​​and depend on many choices, particularly the size of the panel. The advantage of a lower measurement voltage is that it will cause less disturbance to the particle position. This is not necessary, as the peak amplitude during measurement may be higher than during drive. The drive voltage can be reduced while maintaining or approaching the target's transparency or reflectivity, allowing for a relatively higher measurement amplitude.

[0163] Preferably, the measurement duration is very short to avoid changing the position of the particles. Additionally, the current may change during the measurement, which can also be avoided by maintaining a short measurement duration. The degree of shortness of the measurement duration depends on, for example, the speed at which the particles move in the fluid. In one embodiment, the measurement duration is less than, for example, 100 ms, preferably less than 20 ms, such as 16 ms. Using more advanced current sensing circuitry, the current sensing duration can be significantly reduced, for example, to less than 1 ms.

[0164] Measurements can be repeated after a certain amount of time has elapsed. The frequency of repeated measurements depends on many factors. For example, for optical layers with high stability, which have reached their desired transparency or reflectivity, measurements can be repeated after several hours. For faster optical layers, especially during the drive toward the target transparency or reflectivity, measurements can be repeated more frequently, for example, every 100 ms. In one implementation, the drive or hold time is at least five times the measurement time.

[0165] Interestingly, a counter drive signal can be applied after the measurement signal to correct for distortions caused by the measurement. This is unnecessary because normal drive also corrects for particle position, but this feature reduces distortions that the measurement might introduce. For example, if the measurement signal has a lower potential compared to the signal currently used to achieve transparency at the same frequency, the potential of the drive signal can be amplified after the measurement to compensate for the lower measurement signal applied previously.

[0166] During use, the controller is configured to periodically measure the current in the electrodes. The frequency of measurement depends on the application, whether the panel has reached and maintained the desired target transparency or reflectivity, or whether it is actively driven toward the target transparency or reflectivity. For example, measurements could be taken every 100 ms, or once per second. However, for slow-moving optical layers and panels that are being maintained, the measurement frequency may be much lower, for example, as low as once per hour.

[0167] When the target transparency or reflectivity of the optical modulator reaches or falls within a threshold value, the control unit can reduce the amplitude or duty cycle of the potential applied to the electrodes, and / or change the current measurement period. For example, the measurement period can be temporarily increased when the energy in the drive decreases (e.g., when approaching the target). This has the advantage of reducing overshoot.

[0168] Various additional sensors 391 may be mounted on, within, or near the panel 390. For example, one or more temperature sensors may be configured to measure at least one of the external temperature, the internal temperature, and the fluid temperature in the optical layer.

[0169] The higher the temperature of the optical layer, the faster the particles will move. The control unit 370 can be adapted in various ways. For example, current can be measured more frequently because the panel 390 may respond more quickly to changes in the drive signal. Similarly, the drive frequency may increase if the temperature rises. In one embodiment, a lower AC frequency is used when the panel is closed than when it is open. Slower frequencies may increase if the temperature rises. Since the risk of corrosion damage in the electrodes increases with temperature, a more balanced drive is important, which can be achieved with a higher frequency. The relationship between temperature and the measurement or drive frequency can be a function, a lookup table, etc. For example, in one embodiment, the light modulator includes a temperature sensor configured to measure at least one of, for example, an external temperature, an internal temperature, and the temperature of the fluid in the optical layer. For example, the external temperature could be the exterior of a building or car with the light modulator in its outer wall. The controller can be configured to receive the temperature signal from the temperature sensor and determine the drive signal based on that temperature signal. For example, at higher temperatures, a slower but more balanced drive algorithm can be used to achieve its goal, thus avoiding corrosion damage that may occur at higher temperatures.

[0170] For example, a dynamic feedback algorithm can be used, where the feedback parameters depend on temperature. These parameters can be obtained from the temperature, for example, through a lookup table. The feedback control system can have a control function to map a target (e.g., a transparency target, or a current target) to a drive signal (e.g., the potential of multiple electrodes). One embodiment of the feedback control system is a negative feedback system. One embodiment of the control function is a proportional-integral-derivative (PID) control function. The control function can have one or more feedback parameters, such as a so-called gain parameter, that determine how the measured sensed signal changes (e.g., how quickly) the drive signal.

[0171] When determining the drive signal, other parameters of the drive can also be changed, such as by using different sequences of drive signals (e.g., obtained from memory), or by using different parameters (e.g., feedback parameters) in a dynamic feedback algorithm (e.g., an adaptive control loop). For example, the response of an optical modulator may differ as it ages. The controller can compensate for this in the drive.

[0172] The controller can use control algorithms (e.g., dynamic feedback control algorithms, or adaptive control algorithms) to determine the potentials of multiple electrodes, for example, translating a transparency or reflectivity target into a drive signal. The control algorithm can run on a processor system; for example, the software implementing the control algorithm can be stored in electronic memory and executed by one or more microprocessors. Generally, control algorithms (especially dynamic feedback control algorithms) can vary in many ways. For example, the control algorithm can use current-sensing signals to adapt to the drive signal. For example, the current-sensing signal can include (e.g., between electrodes on the same substrate) a horizontal signal, (e.g., between electrodes on opposing substrates) a vertical signal, or both, to control the drive signal. Using current-sensing signals can improve the accuracy of the light modulator, for example, the degree to which a target transparency or reflectivity is achieved. The drive signal typically includes potentials applied to multiple electrodes; however, further parameters can be tuned (e.g., dynamically tuned) to achieve the target. These parameters include (e.g., in addition to potentials) one or more frequencies of the signal applied to the electrodes, and the direction of the electric field. Using more parameters can enable the optical modulator to achieve more precise grayscale values, or change the transition time between two grayscale values, for example, shortening or lengthening the transition time as needed.

[0173] The control algorithm can selectively switch to a lower power consumption mode; for example, when in a lower power consumption mode, the control algorithm can modify the drive signals of multiple electrodes at a lower frequency, for example, at longer time intervals, to reduce power consumption.

[0174] Control algorithms (e.g., dynamic feedback algorithms) can execute different drive schedules depending on the situation. For example, in one implementation, the drive signal can be determined based on the age of the optical modulator. The controller can be configured to maintain the age of the optical modulator. For example, the age can include the amount of time the optical modulator is turned on. A more accurate age can include the amount of time the optical modulator is driven toward a target (e.g., relative to maintaining the target). For example, the control algorithm can be modified to take into account (e.g., changes over time) changes in minimum and maximum calibration currents to recalculate the gray level corresponding to the current target.

[0175] For example, a control algorithm can alter target transparency by interpreting user input and / or sensor signals. In one implementation, target transparency and / or target reflectivity can be set according to a schedule. For example, the user can set the execution with the controller. For instance, the schedule can instruct the controller to have lower transparency around midday when the sun is high, but higher transparency in the afternoon when the sun is low. For instance, the schedule can instruct the controller to increase transparency when the car is moving (especially if traveling at speeds above a threshold), but decrease transparency when the car is parked or traveling at speeds below a threshold.

[0176] The control algorithm can set (e.g., select) the frequency of current measurement, the duration of current measurement, and / or the frequency of the measurement signal. This can be for one or more purposes, such as reducing corrosion, reducing power consumption, reducing transparency transitions, and / or adapting to temperature changes.

[0177] In one embodiment, the controller is configured to temporarily drive electrodes, such as one or more, or all or all of the electrodes connected to the same optical layer, with a measurement signal. The frequency of the measurement signal (which may be an AC signal) may be at least 50 Hz and / or at most 100 Hz. In another embodiment, the frequency of the drive signal (which may also be an AC signal) may be at least 50 Hz and / or at most 100 Hz.

[0178] Figure 4a An embodiment of one implementation of the current sensing circuit 411 is schematically shown. Driving line 121 for electrode 101 is shown. Resistor 401 is included in driving line 121. The current sensing circuit 411 measures the voltage drop across resistor 401 as an indicator of the current through resistor 401. Current signal 422 is transmitted to a controller, such as controller 150 or controller 310, etc.

[0179] Figure 4b An embodiment of one implementation of the current sensing circuit is schematically illustrated. Shown are buffers 431 and 432, one end of which is connected to either side of resistor 401, and the other end of which is connected to the input of programmable gain amplifier 440. The buffers may be precision rail-to-rail input-output opamps, preferably with low current bias.

[0180] Programmable gain amplifier 440 is configured to receive gain signal 442; in this case, it is four-bit, providing 16 different gain settings. Programmable gain amplifier 440 generates a current signal as an output, for example, the voltage drop across resistor 401 as output 441. In this case, output 441 is a differential output (indicating the difference between output signals representing the current through resistor 401), which is not mandatory, although convenient. Current signal 441 can be transmitted to a controller.

[0181] In one implementation, the current sensing circuit can measure current over a wide range, for example, between 10nA and 100mA. This is useful, for example, if the controller is used for different types of panels. Different panel types and sizes have different current requirements. Furthermore, as noted, some currents may become very small during operation. This can be overcome by switching to different currents between other electrodes, but it can also be mitigated by programmable gain. The gain can be used to configure the controller for different panels. Advantageously, the same hardware can be reconfigured for different types of panels.

[0182] Output 441 can be a voltage difference. For example, the current can be calculated from the voltage difference, resistor value R, gain, and reference voltage Vref. For example, in one implementation, I = (output voltage difference) / (R * GAIN * Vref). The reference voltage can be related to the reference voltage of the controller's analog-to-digital converter (ADC).

[0183] Figure 5a and Figure 5b An embodiment of one implementation of an optical modulator is schematically shown. Figure 5b The diagram shows the drive signals; drive signals 511-514 correspond to electrodes 101-104. Figure 5a The diagram shows the field lines, along which the particles move. Under AC drive, the particles in the liquid of the optical layer will bounce between the two substrates.

[0184] Figure 6a and Figure 6b An embodiment of one implementation of turning off the optical modulator is illustrated schematically. Figure 6b The diagram shows the drive signals; drive signals 611-614 correspond to electrodes 101-104. Figure 6a The diagram shows the field lines, which the particles move according to. Under AC drive, the particles in the liquid of the optical layer will bounce between the two electrodes on the same substrate.

[0185] exist Figure 5b and Figure 6bIn the case shown, all maximum amplitudes of all electrodes are equal. In one embodiment, some signals have slightly higher amplitudes, while some signals may have slightly lower amplitudes; one example of this embodiment is... Figure 5c As shown in the diagram. Furthermore, the drive signal will change over time, for example, with changes in parameters such as light, temperature, or target transparency or reflectivity. Additionally, the drive signal may also change when the panel has reached a specific target transparency or reflectivity and only needs to maintain it.

[0186] Figure 7 An embodiment of one implementation of a method 700 for controlling an optical modulator is schematically shown.

[0187] In section 710, the system is calibrated. Calibration can be performed, for example, when the system is first turned on, after a long period of inactivity, or when the system detects values ​​outside its range. For example, the measured current exceeds the range observed during calibration. In section 720, the current at each electrode in the optical modulator panel is measured.

[0188] In part 730, internal and external light levels are measured, for example, using an inverse logarithmic scale to define the target transparency of the light modulator panel; for example, light sensors can be applied to both sides of the panel. For example, for a window with smart glass, the light level inside the room and the light level outside the room and outside the window can be measured.

[0189] In addition to light levels, the temperature sensor can measure external temperature, internal temperature, and / or the temperature of liquids inside the panel.

[0190] The temperature of the liquid can affect the panel's performance. For example, the drive frequency and current measurement interval may change. The current measurement interval is a time interval after which a portion of the 720's current measurements are repeated.

[0191] In section 740, the output to the light modulator panel is calculated from measured current, illumination level, and temperature. For example, a grayscale table can be defined, which the controller can use to define the panel. These can be used as setpoints for a feedback algorithm. The table can also be used as a selection table that a user (e.g., with a device connected to the system) can choose from. The user device can be wired or wireless, such as a button, mobile phone, etc. In section 750, the electrodes are driven based on the calculated output.

[0192] Typically, a drive signal is calculated for each electrode of the panel. Furthermore, different target transparency or target reflectivity, or transitions between different transparency or reflectivity, may require different drive signals. The voltage, frequency, and duty cycle of the drive signal for each electrode may differ to drive towards the target transparency or target reflectivity.

[0193] In section 760, new input may be detected, such as new target transparency from the user, or desired ambient light level, or new sensor values, for example, from a light sensor or temperature sensor. In section 770, it is determined whether new calibration is needed, or preferably, for example, if a value out of range is detected. Values ​​out of range may include large temperature variations, exceeding thresholds, failure to reach target transparency or target reflectivity levels in a timely manner, and so on.

[0194] If the panel is not driven, the system can enter sleep mode. Figure 7 The implementation scheme described herein is one example and can be varied in many ways, as also noted herein. For example, using a light sensor or a temperature sensor is optional. For example, instead of an AC signal, a balanced DC drive can be used, and so on.

[0195] Figure 8 An embodiment of a control method 800 for an optical modulator panel is schematically illustrated. Control 800 includes:

[0196] Calibration 810 involves measuring the current in the electrodes under more than one known state of the panel. Calibration 810 may include determining the maximum and minimum values ​​for additional parameters, such as panel performance, positive voltage, negative voltage and reference voltage, temperature offset, light offset, grayscale selection offset, user input offset, etc. Calibration can be performed at the factory before use, or alternatively, at the customer's site. Calibration can be repeated, in whole or in part, when the system is turned on, restarted, reset, timed out, periodically, etc.

[0197] Obtain sensor values ​​820. For example, obtaining sensor values ​​could include obtaining the external temperature, room temperature, and the internal temperature of the optical layer. The temperature of the optical layer affects the state of the panel. Measuring the temperature of the optical layer allows the control algorithm to react to the temperature. Sensor values ​​could also include external ambient light and room ambient light. For example, this could be used to maintain a stable room ambient light.

[0198] Set the target transparency to 830. The target transparency can be calculated from the room's ambient light level. It can also be set directly by the user through the user interface.

[0199] Drive panel 840. The panel can be driven for a period of time. In the first iteration, this may be the initial drive signal. The initial drive signal can be the default drive signal. The initial drive signal can depend on the calculated actual transparency level.

[0200] The current measuring device 850 can measure the current in the electrodes after a period of driving. This may include setting a measurement signal on the electrodes. The current measuring device 850 is interchangeable with the drive device 840.

[0201] Adapted drive signal 860. The drive algorithm (e.g., a control algorithm such as a closed-loop feedback algorithm) can modify the drive signal so that a portion of the current measured at 850 will converge toward a calculated current corresponding to the target transparency. The calculated current can be obtained by interpolating the current measured during calibration.

[0202] The following is an exemplary implementation of an optical modulator.

[0203] Figure 9a An embodiment of the light modulator 10 is schematically shown, which can be applied in smart glass.

[0204] Reference is made to patent application PCT / EP2020 / 052379, which is incorporated herein by reference; the application includes an advantageous design of an optical modulator that can be further improved, for example, by including electrodes and / or branches, as explained herein.

[0205] The optical modulator 10 can electronically switch between a transparent state and an opaque state, and vice versa, or between a reflective state and an opaque state, and vice versa. The optical modulator 10 includes a first substrate 11 and a second substrate 12, which are arranged opposite to each other. At least two electrodes are applied on the inner side 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 on the inner side of the second substrate 12: electrodes 14a and 14b are shown. These at least two electrodes are collectively referred to as electrode 14. A current sensing circuit can be installed in electrodes 13a and 13b, and 14a and 14b.

[0206] A fluid 15 is provided between the substrates. This fluid includes particles 30, such as nanoparticles and / or microparticles, wherein the particles are charged or rechargeable. Electrodes are arranged to drive the particles 30 toward or away from the electrodes, depending on the applied electric field. Optical properties (particularly the transparency of the light modulator) depend on the position of the particles 30 in the fluid. For example, connectors may be provided for applying an electromagnetic field to the electrodes. The illustrated controller 16 is configured to receive a current sensing signal and generate drive signals for electrodes 13 and 14.

[0207] In one embodiment, substrates 11 and 12 may be optically transparent, external to the electrodes, and typically >95% transparent, such as >99% transparent, at the relevant wavelengths. The term "optical" may refer to wavelengths visible to the human eye (about 380 nm to about 750 nm) (where applicable), and may refer to a wider range of wavelengths including infrared (about 750 nm to 150 nm) and ultraviolet (about 10 nm to 380 nm), and sub-selections thereof (where applicable). In one exemplary embodiment of the optical modulator, the substrate material is selected from glass and polymers.

[0208] In another embodiment, one substrate (such as bottom substrate 12) may be reflective or partially reflective, while top substrate 11 is transparent. Optical properties (particularly the reflectivity of the light modulator) depend on the position of the particles 30 in the fluid. When the panel is in the open state (vertically driven), the particles will be mostly located between the opposing electrodes of the two substrates, allowing incident light to pass relatively unimpeded through the transparent top substrate and optical layer, and to be reflected or partially reflected on the bottom substrate.

[0209] 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 even more preferably less than 50 μm, such as less than 30 μm.

[0210] In one embodiment, the modulator may be provided as a flexible polymer, while the remainder of the device may be provided as glass. The glass may be rigid or flexible. A protective layer may be provided on the substrate if desired. If more than one color is provided, more than one flexible polymer layer may be provided. The polymer may be polyethylene naphthalate (PEN), polyethylene terephthalate (PET) (optionally having a SiN layer), polyethylene (PE), etc. In another embodiment, the device may be provided as at least one flexible polymer. Therefore, the modulator can be attached to any surface, such as by using an adhesive.

[0211] Particle 30 may be adapted to absorb light, thereby preventing certain wavelengths of light from passing through. Particle 30 may reflect light; for example, the reflection may be specular reflection, diffuse reflection, or something in between. The particle may absorb certain wavelengths while reflecting others.

[0212] In one exemplary embodiment of the optical modulator, the nanoparticles have a size of 20-1000 nm, preferably 20 nm-300 nm, and more preferably less than 200 nm. In one exemplary embodiment of the optical modulator, the nanoparticles / microparticles may comprise a coating on a pigment, preferably comprising a core. In one exemplary embodiment of the optical modulator, the coating on the particles is made of a material selected from conductive and semiconductive materials.

[0213] In one exemplary embodiment of the optical modulator, the particles are adapted to absorb light with wavelengths of 10 nm to 1 mm, such as light with wavelengths of 400 nm to 800 nm, 700 nm to 10 nm, and 10 nm to 400 nm, and / or to absorb a portion of light with wavelengths falling within the 10 nm to 1 mm range (filter), and combinations thereof.

[0214] In one exemplary embodiment of the optical modulator, the particles are charged or rechargeable. For example, the charge on the particles can be 0.1e to 10e per particle (5*10). -7 -0.1C / m2). For example, suitable embodiments of such particles are provided in US 4680103 A, which is incorporated herein by reference.

[0215] In one exemplary embodiment of the optical modulator, the fluid is present in an amount of 1-1000 g / m², preferably 2-75 g / m², more preferably 20-50 g / m², such as 30-40 g / m². A significant advantage is that, in the layout of the present invention, much less fluid can be used, and similarly, much less particles can be used.

[0216] In one exemplary embodiment of the optical modulator, the particles are present in amounts of 0.01-70 g / m², preferably 0.02-10 g / m², such as 0.1-3 g / m².

[0217] In one exemplary embodiment of the light modulator, the color of the particles is selected from cyan, magenta, and yellow, as well as black and white, and combinations thereof.

[0218] In one exemplary embodiment of the optical modulator, the fluid includes one or more of a surfactant, an emulsifier, a polar compound, and a compound capable of forming hydrogen bonds.

[0219] Fluid 15 may be a nonpolar fluid with a dielectric constant less than 15. In one exemplary embodiment of the optical modulator, the relative dielectric constant ε of the fluid is not less than 100, preferably less than 10, such as less than 5. In one exemplary embodiment of the optical modulator, the dynamic viscosity of fluid 15 is greater than 10 mPa·s.

[0220] Electrodes 13a, 13b and electrodes 14a, 14b are in fluid contact with a fluid. The fluid can contact the electrodes directly or indirectly, for example, through a second medium (such as through a porous layer). In one embodiment, the electrodes cover about 1-30% of the substrate surface. In one embodiment, the electrodes comprise a conductive material with a surface resistivity of less than 10,000 ohms / square (Ω square), preferably less than 100, more preferably less than 10, and more preferably less than 10. In one embodiment of the optical modulator, one or more electrodes comprise one or more metals selected from copper, silver, gold, aluminum, graphene, titanium, and indium, preferably copper. The electrodes can be in the form of microwires embedded in a polymer-based substrate; for example, copper microwires.

[0221] Connectors are used to apply electromagnetic fields to electrodes, wherein the electromagnetic fields applied to the electrodes provide motion of nanoparticles and microparticles from a first electrode to a second electrode and vice versa. Connectors for applying electromagnetic fields to electrodes can be provided. For example, in an exemplary embodiment of the optical modulator, the current is between -100 μA and +100 μA, preferably between -30 μA and +30 μA, more preferably between -25 μA and +25 μA. For example, a power supply can be electrically connected to at least two electrodes. The power supply can be adapted to provide waveform power. At least one of amplitude, frequency, and phase is adaptable to provide different states in the optical modulator. For example, aspects of the power supply can be adapted by a controller.

[0222] The light modulator 10 may include one or more pixels, typically multiple pixels, where a pixel is a single optically switchable entity of varying sizes. A substrate at least partially encloses a volume, which may be a pixel. This design allows for stacking to allow for more colors; for example, for full-color applications, a stack of two or three modulators may provide most or all of the colors respectively. The device may include driving circuitry for altering the appearance of a (single) pixel by applying an electromagnetic field. Therefore, the appearance of the light modulator, or one or more portions thereof, can also be altered.

[0223] In one exemplary embodiment of the light modulator, the light modulator comprises less than one pixel per mm². Having one or more pixels allows the light modulator to be locally controlled; this is advantageous for some applications but not essential. For smart glass, the light modulator may or may not use pixels. For example, when applied in smart glass, transparency or reflectivity can be locally controlled, for instance, to block sunlight spots without reducing the overall transparency or reflectivity of the window.

[0224] In one exemplary embodiment of the optical modulator, substrates (11, 12) are aligned, and / or electrodes (13, 14) are aligned. For example, electrodes 13a, 13b and electrodes 14a, 14b may be aligned so that they are opposite each other. In the aligned substrates, when viewed from a direction orthogonal to the substrates, the electrodes on the different substrates will fall behind each other. When the optical modulator is disassembled, the substrates are all arranged with their electrode surfaces facing upwards, so the electrode patterns are mirror images of each other.

[0225] Aligning the substrates can increase the maximum transparency or reflectivity of the optical modulator. On the other hand, when the criteria for selecting the optical modulator are more extensive than a range such as transparency or reflectivity, it may be better to misalign or not perfectly align the two substrates. Optical modulators can be stacked. For example, two stacked optical modulators can be made from three substrates, with the middle substrate having electrodes on both of its surfaces. In one embodiment of the optical modulator, optionally, at least one substrate 11, 12 of the first optical modulator is identical to substrate 11, 12 of at least one second optical modulator. Furthermore, for stacked modulators, alignment can increase maximum transparency or reflectivity but may be detrimental to other considerations, such as diffraction.

[0226] Figure 9b An embodiment of one implementation of the optical modulator 40 is schematically shown. The optical modulator 40 is similar to the optical modulator 10, except that it includes multiple optical layers; in the illustrated embodiment, there are two optical layers. More than two optical layers may be present. Each optical layer is disposed between two substrates. The optical modulator 40 can be considered as follows: Figure 9a The two substrate optical modulators are stacked. As shown, the optical modulator 40 includes three substrates: a first substrate 41, a second substrate 42, and a third substrate 43. An optical layer is located between substrates 41 and 42, and another optical layer is located between substrates 42 and 43. These optical layers may be similar to those in the optical modulator 10. A controller 46 is configured to control the current on the electrodes of the substrates. For example, in… Figure 9b In this configuration, the controller 46 can be electrically connected to at least 4 by 2 equals 8 electrodes.

[0227] Interestingly, the particles in multiple optical layers can be different, allowing multiple optical layers to be used to control more optical properties of the light modulator. For example, particles in different optical layers can absorb or reflect at different wavelengths, and thus can have different colors. This can be used by controller 46 to generate different colors and / or different color intensities on the panel. For example, a panel with four substrates can have three optical layers with particles of different colors, such as cyan, yellow, and magenta, respectively. By controlling the transparency or reflectivity of different colors, a wide color gamut can be produced.

[0228] For example, in one embodiment, the surfaces of other substrates facing one substrate may be provided with two or more patterns. For example, outer substrates 41 and 43 may receive electrodes only on their inner sides, while inner substrates (e.g., substrate 42) may have electrodes on both sides.

[0229] Substrates 41 and 42 can be considered together as one embodiment of an optical modulator. Similarly, substrates 42 and 43 can be considered together as one embodiment of an optical modulator.

[0230] Figure 9c An embodiment of an automobile 20 having smart glass for window 21 is schematically illustrated. This is a particularly advantageous embodiment because the level of incident light can change frequently and rapidly while driving. The advantage of using smart glass in an automobile is that the light level can be maintained at a constant level by adjusting the transparency of the windows. Furthermore, improved driving can enhance safety due to the more precise transparency of the windows. For example, when windows darken, they are less likely to darken excessively, or vice versa. The automobile 20 may include a controller configured to control the transparency of window 21.

[0231] Smart glass can also be used in other glass applications, particularly where the amount of incident light is variable, such as in buildings, offices, houses, greenhouses, and skylights. Skylights are windows installed in the ceiling to allow sunlight into a room.

[0232] Figures 10a-10b A side view of one embodiment of an optical modulator in use is schematically shown. Applying an electric field to electrodes on a substrate generates an electrodynamic force on particles. Utilizing this effect, the particles can move around, thus creating different states of transparency or reflectivity within the optical modulator. A controller can control the electric field, for example, its amplitude, frequency, and phase. In one embodiment, the controller is connected to at least four electrodes: two per substrate. However, more electrodes can be used and connected to the controller; for example, the substrate can use more than two electrodes to achieve greater control over grayscale or to obtain specific optical patterns.

[0233] Figure 10a An optical modulator without an applied electric field is shown. Figure 10a In the process, no electrodynamic force has yet been applied to the particles 30 suspended in the fluid 15.

[0234] exist Figure 10a In the configuration shown, the conductive electrode patterns arranged on the top substrate are fully or substantially aligned with the conductive electrode patterns on the bottom substrate to obtain the desired electrode configuration. The conductive electrode patterns can be deposited on transparent, reflective, or partially reflective substrates, or embedded in plastic substrates, etc.

[0235] Alignment between the top and bottom electrode patterns contributes to a wider range of achievable transparency or reflectivity levels. However, alignment is unnecessary, as a similar effect can be obtained without alignment. A certain range of transparency or reflectivity can also be achieved without alignment.

[0236] It should be noted that in these embodiments, the references to the top substrate and bottom substrate refer to the substrate higher or lower on the page. The same substrates may also be referred to as, for example, the front substrate and the rear substrate, because in glass applications, the substrates are aligned vertically rather than horizontally.

[0237] Figure 10b A light modulator is illustrated in which, for example in example P1, a potential of +V1 is applied to each electrode on the top substrate, while a negative voltage (e.g., -V1) is applied to each electrode on the bottom substrate. Thus, in this case, the same positive potential is applied to all electrodes 13, and the same negative potential is applied to electrode 14. The potential difference causes negatively charged particles to flow towards the vicinity of the electrodes on the top substrate, where these particles will substantially align with the top electrodes. If the solution contains positively charged particles, they will flow towards the vicinity of the electrodes on the bottom substrate, where these particles will substantially align with the bottom electrodes. Therefore, if both the top and bottom substrates are transparent, the transparency of the light modulator 10 will increase. Similarly, if, for example, the top substrate is transparent and the bottom substrate is reflective, the reflectivity of the light modulator 10 will increase. A similar transparency or reflectivity can be achieved when, in a second example P2 in the power-on state, the voltages of the top and bottom electrodes are opposite to those in example P1. In example P2, the voltage of each electrode on the top substrate is now supplied with a negative potential -V1, while the voltage of the alignment electrode on the bottom substrate is supplied with a positive potential. This state is similar to... Figure 10b The state shown is reversed for the top and bottom substrates. Additionally, in this configuration, the light modulator 10 has high transparency or reflectivity.

[0238] Similarly, electrodes 13 and 14 are processed such that, under high time variations (AC signals) from P1 to P2, the particles will align within the electric field lines between the electrodes (without needing to reach the electrode positions). Therefore, if both the top and bottom substrates are transparent, the transparency of the light modulator 10 will increase. Likewise, if, for example, the top substrate is transparent and the bottom substrate is reflective, the reflectivity of the light modulator 10 will increase.

[0239] Interestingly, by using a positive potential at the electrodes of the top substrate (e.g., as...) Figure 10bThe negative potential at electrode 13 (and electrode 14) and the positive potential at the electrode on the bottom substrate (e.g., as shown) Figure 10b The continuous switching between electrode 14 (shown as an example) and the negative potential on electrode 13 can maintain transparency or reflectivity while reducing corrosion damage to the electrodes. This alternating electric field can be achieved by applying alternating potentials to the top and bottom electrodes.

[0240] Applying a waveform is optional, but it is a useful measure to increase the lifetime of an optical modulator by reducing corrosion. For example, when using copper electrodes, corrosion may occur because copper ions dissolve in the ion fluid of one substrate and flow to the copper electrode on the opposite substrate, where they deposit. By applying a waveform, the transport direction of copper ions is often reversed, thereby reducing corrosion damage. Between two instances P1 and P2, the corrosion current between the two substrates is balanced or substantially (e.g., >95%) balanced; for example, as corrosion occurs at the top electrode, a balanced copper deposition exists on the bottom electrode between each instance P1 and, conversely, between instances P2. Therefore, particles constantly change or migrate between the top and bottom electrodes, the optical modulator or smart window is always open, and the dynamic electrolytic current between the top and bottom electrodes is constant, so there is no net loss or negligible net loss of copper electrode material on the top and bottom substrates.

[0241] Figure 10c This illustrates how a state of reduced transparency or reflectivity can be achieved by applying an alternating voltage to the same substrate. For example, in one embodiment, a potential of +V2 is applied to the first electrode, and the next adjacent electrode has an opposite potential of -V2, etc. Figure 10c As shown. This can be achieved by applying a potential +V2 to electrode 13a and an opposite potential -V2 to electrode 13b. On opposing substrates, a potential +V2 can be applied to electrode 14a, and an opposite potential -V2 to electrode 14b. For example, the electrodes can be arranged such that electrodes on the substrates are aligned; the electrode on the top substrate has an electrode opposite to the electrode on the bottom substrate, and vice versa. For example, to reduce transparency or reflectivity, opposing electrodes can receive the same potential, while adjacent electrodes receive an opposite potential. One embodiment is as follows. Figure 10c As shown, four electrodes are indicated by reference numerals 13a, 13b, 14a, and 14b, while the remaining electrodes continue to alternate.

[0242] By using this AC drive cycle between the top and bottom substrates, a diagonal and lateral electric field is generated between the two substrates, resulting in the random diffusion of particles and thus producing the off state of the optical modulator. As a result of this configuration, the particles migrate diagonally and laterally between the top and bottom substrates, diffusing into the visible light aperture of the optical modulator, contributing to the off, opaque state of the optical modulator.

[0243] As for Figure 10b The transparent state shown allows for the application of waveforms to the electrodes, for example, to make... Figure 10b The diagram shows an electrode with a positive potential becoming a negative potential, and vice versa. For example... Figure 10b In this process, for example, applying a waveform between electrodes 13a and 13b and between electrodes 14a and 14b can reduce corrosion damage to the electrodes.

[0244] AC-driven loops can be implemented using interdigitated line configurations, for example, by combining... Figure 2a or Figure 2b The top and bottom electrode configurations are shown in the plan view.

[0245] Figure 10b and Figure 10c The degree to which transparency or reflectivity increases or decreases depends on the amplitude (voltage), frequency, and bias difference of the electrical signal. By changing the amplitude difference, the amount by which transparency or reflectivity increases or decreases, respectively, can be controlled. For example, a curve representing light transmission versus voltage can be determined (e.g., measured). To obtain a specific level of light transmission (e.g., a specific level of transparency, such as a specific grayscale level), a corresponding voltage (e.g., AC voltage) can be applied. By interpolating the signal in the transparent or opaque state, the level between transparency and opacity can be obtained. Similarly, a curve representing light reflection versus voltage can be determined (e.g., measured). To obtain a specific level of reflectivity, a corresponding voltage (e.g., AC voltage) can be applied. By interpolating the signal in the reflective or non-reflective state, the level between reflectivity and non-reflectivity can be obtained.

[0246] Figure 11 An embodiment of a method 900 for controlling an optical modulator according to one embodiment is illustrated schematically. The method can be implemented by a computer. The method includes:

[0247] - Receive (910) at least one current sensing signal from at least one current sensing circuit, the at least one current sensing signal indicating the current in the corresponding electrode;

[0248] - Determine the driving signal of the (920) electrode from at least one current sensing signal and from the target transparency;

[0249] - A drive signal is transmitted (930) to an optical modulator to apply a potential to a plurality of electrodes according to the drive signal, thereby obtaining an electromagnetic field between the plurality of electrodes, wherein the electromagnetic field provides electrophoretic motion of particles toward or away from one of the plurality of electrodes.

[0250] Many different ways of performing this method are possible, as will be apparent to those skilled in the art. For example, the steps can be performed in the order shown, but the order of the steps can be changed, or some steps can be performed in parallel. Furthermore, other method steps can be inserted between the steps. The inserted steps may represent an improvement to the method described herein, or they may be unrelated to the method. For example, some steps may be performed at least partially in parallel. Moreover, a given step may not be fully completed before the next step begins.

[0251] Implementations of this method can be executed using software comprising instructions that cause a processor system to execute method 900. The software may include only those steps taken by a specific sub-entity of the system. The software may be stored on a suitable storage medium (e.g., hard disk, floppy disk, memory, optical disk, etc.). The software may be transmitted as a signal over wires or wirelessly or using a data network (e.g., the Internet). The software may be available for download and / or remote use on a server. Implementations of this method can also be executed using a bitstream configured to configure programmable logic (e.g., a field-programmable gate array (FPGA)) to execute the method.

[0252] It will be understood that the subject matter of this disclosure also extends to computer programs suitable for implementing the subject matter of this disclosure, particularly computer programs on or in a carrier. The program may be source code, object code, intermediate source code, and object code in the form of partially compiled code, or any other form suitable for implementing one embodiment of the method. One embodiment relating to a computer program product includes computer-executable instructions corresponding to each processing step of at least one of the elaborated methods. These instructions may be subdivided into subroutines and / or stored in one or more files that may be statically or dynamically linked. Another embodiment relating to a computer program product includes computer-executable instructions corresponding to each device, unit, and / or component of at least one of the elaborated systems and / or products.

[0253] Figure 12aA computer-readable medium 1000 is shown having a writable portion 1010 including a computer program 1020 comprising instructions for causing a processor system to execute an optical modulator method according to one embodiment. The computer program 1020 may be included on the computer-readable medium 1000 as a physical label or by magnetization of the computer-readable medium 1000. However, any other suitable embodiments are contemplated. Furthermore, it will be understood that although the computer-readable medium 1000 is shown herein as an optical disc, the computer-readable medium 1000 may be any suitable computer-readable medium, such as a hard disk, solid-state storage, flash memory, etc., and may be non-recordable or recordable. The computer program 1020 includes instructions for causing a processor system to execute an optical modulator method.

[0254] Figure 12b A processor system 1140 for a controller of an optical modulator, according to one embodiment, is shown schematically. The processor system includes one or more integrated circuits 1110. Figure 12b The diagram schematically illustrates the structure of one or more integrated circuits 1110. Circuit 1110 includes a processing unit 1120 (e.g., a CPU) for running computer program components to perform a method according to one embodiment and / or implement its modules or units. Circuit 1110 includes a memory 1122 for storing programming code, data, etc. A portion of the memory 1122 may be read-only. Circuit 1110 may include a communication element 1126, such as an antenna, a connector, or both or the like. Circuit 1110 may include an application-specific integrated circuit 1124 for performing some or all of the processing defined in the method. Processor 1120, memory 1122, application-specific integrated circuit 1124, and communication element 1126 may be interconnected with each other via interconnect 1130 (e.g., a bus). Processor system 1110 may be arranged for contact communication and / or contactless communication, using an antenna and / or a connector, respectively.

[0255] For example, in one embodiment, the processor system 1140, for instance, may include processor circuitry and storage circuitry, the processor being configured to execute software stored in the storage circuitry. For example, the processor circuitry may be an Intel Core i7 processor, an ARM Cortex-R8, etc. In one embodiment, the processor circuitry may be an ARM Cortex M0. The memory circuitry may be ROM circuitry or non-volatile memory, such as flash memory. Alternatively, the memory circuitry may be volatile memory, such as SRAM memory. In the latter case, the device may include a non-volatile software interface (e.g., a hard disk, a network interface, etc.) configured to provide software.

[0256] A controller for an optical modulator (e.g., controlling the voltage applied to the electrodes) may include processor circuitry, but may also include or alternatively include a state machine.

[0257] The following numbered clauses include conceivable and non-limiting embodiments:

[0258] Clause 1. An electrophoretic light modulator, comprising: an electrically adaptable glass, said glass comprising:

[0259] A first substrate and a second substrate are arranged with their inner sides facing each other. A plurality of electrodes are applied to the inner sides of each of the first substrate and the second substrate, each of the plurality of electrodes being arranged in a transverse pattern across the substrate. Applying a potential to the plurality of electrodes causes an electromagnetic field to be generated between the plurality of electrodes. Each of the plurality of electrodes includes:

[0260] Multiple main lines, the multiple main lines extending across the substrate in a first direction, the multiple main lines of the multiple electrodes being arranged alternately relative to each other on the substrate;

[0261] An optical layer enclosed between a first substrate and a second substrate, the optical layer comprising:

[0262] A fluid enclosed between a first substrate and a second substrate, the fluid comprising particles, wherein the particles are charged and wherein the particles are adapted to absorb or reflect light, wherein an electromagnetic field between a plurality of electrodes provides electrophoretic motion of the particles toward or away from one of the plurality of electrodes;

[0263] At least one current sensing circuit is connected to one of a plurality of electrodes, the current sensing circuit being configured to measure current in the connected electrode; and a controller comprising a controller system configured to:

[0264] Receive at least one current sensing signal from at least one current sensing circuit, the at least one current sensing signal indicating the current in the connected electrode;

[0265] The driving signals for the plurality of electrodes are determined from the at least one current sensing signal and from the target transparency or target reflectivity; and

[0266] A potential is applied to the plurality of electrodes according to the driving signal.

[0267] Clause 2. An electrophoretic light modulator as described in Clause 1, wherein the fluid includes a dielectric fluid.

[0268] Clause 3. An electrophoretic optical modulator as described in Clause 1 or 2, wherein the fluid comprises a nonpolar fluid with a dielectric constant less than 15.

[0269] Clause 4. An electrophoretic light modulator as described in any one of Clauses 1 to 3, wherein the particles comprise pigment particles containing inorganic pigments.

[0270] Clause 5. An electrophoretic light modulator as described in Clause 4, wherein the inorganic pigment comprises titanium dioxide, aluminum oxide, silicon dioxide, or mixtures thereof.

[0271] Clause 6. An electrophoretic light modulator as described in Clause 4 and / or Clause 5, wherein the pigment particles are positively or negatively charged.

[0272] Clause 7. A method for electrophoretic light modulator, comprising: providing a light modulator, the light modulator comprising: electrically adaptable glass, the glass comprising:

[0273] A first substrate and a second substrate are arranged with their inner sides facing each other. A plurality of electrodes are applied to the inner sides of each of the first substrate and the second substrate, each of the plurality of electrodes being arranged in a transverse pattern across the substrate. Applying a potential to the plurality of electrodes causes an electromagnetic field to be generated between the plurality of electrodes. Each of the plurality of electrodes includes:

[0274] Multiple main lines, the multiple main lines extending across the substrate in a first direction, the multiple main lines of the multiple electrodes being arranged alternately relative to each other on the substrate;

[0275] An optical layer enclosed between a first substrate and a second substrate, the optical layer comprising:

[0276] A fluid enclosed between a first substrate and a second substrate, the fluid comprising particles, wherein the particles are charged and wherein the particles are adapted to absorb or reflect light, wherein an electromagnetic field between a plurality of electrodes provides electrophoretic motion of the particles toward or away from one of the plurality of electrodes;

[0277] At least one current sensing circuit is connected to one of a plurality of electrodes, the current sensing circuit being configured to measure the current in the connected electrode;

[0278] Receive at least one current sensing signal from at least one current sensing circuit, the at least one current sensing signal indicating the current in the corresponding electrode;

[0279] The driving signal for the electrode is determined from the at least one current sensing signal and from the target transparency or target reflectivity; and

[0280] The drive signal is transmitted to the optical modulator to apply a potential to the plurality of electrodes according to the drive signal.

[0281] It should be noted that the embodiments mentioned above are illustrative and not limiting of the subject matter of this disclosure, and those skilled in the art can devise many alternative embodiments.

[0282] In the claims, any reference numerals enclosed in parentheses shall not be construed as limiting the claims. The use of the verb “comprise” and its variations does not exclude the presence of elements or steps other than those recited in the claims. The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. When an expression such as “at least one” precedes a list of elements, it indicates the selection of all elements or any subset thereof from the list. For example, the expression “at least one of A, B, and C” should be understood to include only A, only B, only C, both A and B, both A and C, both B and C, or all of A, B, and C. The subject matter of this disclosure can be implemented by hardware comprising several different elements, as well as by a suitably programmed computer. In device claims enumerating several parts, several of these parts can be implemented by the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to exert an advantage.

[0283] In the claims, the marks enclosed in parentheses refer to reference symbols in the figures of exemplary embodiments or formulas of embodiments, thereby improving the comprehensibility of the claims. These marks should not be construed as limiting the claims.

Claims

1. An electrophoretic light modulator, the electrophoretic light modulator comprising smart glass for a window, the smart glass comprising: A first substrate and a second substrate are arranged with their inner sides facing each other. A plurality of electrodes are applied to the inner sides of each of the first and second substrates. Each of the plurality of electrodes on the first and second substrates is arranged in an interdigital pattern across the substrates. Applying a potential to the plurality of electrodes causes an electromagnetic field to be generated between the plurality of electrodes. Each of the plurality of electrodes includes: Multiple main lines, the multiple main lines extending across the substrate in a first direction, the multiple main lines of the multiple electrodes being arranged alternately relative to each other on the substrate; An optical layer, the optical layer being between a first substrate and a second substrate, the optical layer comprising: a fluid comprising particles, wherein the particles are charged or rechargeable and wherein the particles are adapted to absorb or reflect light, wherein an electromagnetic field between the plurality of electrodes provides electrophoretic motion of the particles toward or away from one of the plurality of electrodes; At least one current sensing circuit is connected to one of the plurality of electrodes, the current sensing circuit being configured to measure the current in the electrode to which it is connected when driven by a measurement signal temporarily applied during the measurement duration, wherein the measurement signal is an AC signal with a frequency of at most 100 Hz; and A controller configured to: receive at least one current sensing signal from at least one current sensing circuit during the measurement duration, the at least one current sensing signal indicating current in connected electrodes; determine drive signals for the plurality of electrodes from the at least one current sensing signal and from target transparency or target reflectivity; and apply the potential to the plurality of electrodes according to the drive signals when the measurement duration ends.

2. The electrophoretic light modulator according to claim 1, wherein the driving signal is provided in the form of alternating current (AC) in the plurality of electrodes to obtain a substantially balanced electrolytic current.

3. The electrophoretic light modulator of claim 1, wherein the driving signal is provided in the form of direct current (DC) in the plurality of electrodes, wherein the voltage is periodically reversed to obtain a substantially balanced electrolytic current.

4. The electrophoretic light modulator according to claim 1 or 2, wherein the first substrate and the second substrate are transparent.

5. The electrophoretic light modulator according to claim 1 or 2, 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.

6. The electrophoretic optical modulator according to claim 1 or 2, comprising a plurality of current sensing circuits, each electrode being connected to a corresponding one of the plurality of current sensing circuits.

7. The electrophoretic optical modulator according to claim 1 or 2, wherein the controller is configured to: The transparency or reflectivity level of the optical modulator is determined from the at least one current sensing signal.

8. The electrophoretic optical modulator according to claim 1 or 2, wherein the controller is configured to: During the measurement duration, a potential is applied to at least one electrode according to the measurement potential; During the measurement duration, at least one current sensing signal is received from at least one current sensing circuit connected to the electrode; and After measuring the duration, a potential is applied to the electrodes according to the drive signal.

9. The electrophoretic optical modulator of claim 8, wherein the potential is a constant AC signal, and all electrodes are simultaneously or continuously driven by the constant AC signal to evaluate the current on all electrodes during the measurement duration.

10. The electrophoretic optical modulator according to claim 1 or 2, wherein the controller is configured to periodically measure the current in the electrodes.

11. The electrophoretic optical modulator of claim 10, comprising a temperature sensor configured to measure at least one of an external temperature, an internal temperature, and a fluid temperature in an optical layer, wherein the controller is configured to receive a temperature signal from the temperature sensor and to determine a current measurement period from the temperature signal.

12. The electrophoretic optical modulator according to claim 1 or 2, wherein the controller is configured to determine a drive signal for each electrode, and the drive signals for at least three of the plurality of electrodes on the first and second substrates are different, resulting in different potentials being applied to the at least three electrodes simultaneously.

13. The electrophoretic optical modulator according to claim 1 or 2, wherein the controller is configured to perform calibration of the optical modulator, the calibration comprising: A potential is applied to multiple electrodes to drive the optical modulator to achieve maximum transparency, and / or minimum transparency, and / or maximum reflectivity, and / or minimum reflectivity; as well as At least one current sensing signal is received from the at least one current sensing circuit, the current sensing signal corresponding to maximum transparency, and / or minimum transparency, and / or maximum reflectivity, and / or minimum reflectivity.

14. The electrophoretic light modulator of claim 13, wherein, in the use phase after calibration, the driving signal is determined from at least one current sensing signal obtained in the use phase, at least one current sensing signal obtained in the calibration, and from the target transparency or target reflectivity.

15. The electrophoretic light modulator of claim 13, wherein the controller is configured to calibrate at least one of the following: first turning on the light modulator, turning on the light modulator after the light modulator has been off for more than a threshold time, measuring an out-of-range current, or failing to reach a transparency or reflectivity level within a threshold time.

16. The electrophoretic optical modulator according to claim 1 or 2, wherein determining the drive signal includes determining one or more of the voltage, AC frequency, bias voltage, waveform shape and duty cycle of each electrode.

17. The electrophoretic light modulator according to claim 1 or 2, wherein the target transparency or target reflectivity is obtained from user input and / or from sensor signals of the light sensor.

18. The electrophoretic light modulator according to claim 1 or 2, wherein the controller is configured to, when the target transparency or target reflectivity of the light modulator reaches a threshold of target transparency or target reflectivity or is within a threshold of target transparency or target reflectivity, Reduce the magnitude or duty cycle of the potential applied to the electrode; and / or Change the current measurement period.

19. The electrophoretic optical modulator according to claim 1 or 2, wherein: The controller is configured to maintain the usage time of the optical modulator and further determine a drive signal based on the usage time; and / or The optical modulator includes a temperature sensor configured to measure at least one of an external temperature, an internal temperature, and a fluid temperature in the optical layer, and the controller is configured to receive a temperature signal from the temperature sensor and further determine a drive signal based on the temperature signal.

20. The electrophoretic optical modulator according to claim 1 or 2, wherein the driving signal is determined according to a dynamic feedback control algorithm.

21. A method for electrophoretic optical modulator, comprising: A light modulator is provided, the light modulator comprising smart glass for a window, the smart glass comprising: A first substrate and a second substrate are arranged with their inner sides facing each other. A plurality of electrodes are applied to the inner side of each of the first substrate and the second substrate. Each of the plurality of electrodes on the first substrate and the second substrate is arranged in an interdigital pattern across the substrate. Applying a potential to the plurality of electrodes causes an electromagnetic field to be generated between the plurality of electrodes. Each of the plurality of electrodes includes a plurality of main lines that extend across the substrate in a first direction. The plurality of main lines of the plurality of electrodes are arranged alternately relative to each other on the substrate. An optical layer, situated between a first substrate and a second substrate, comprising: a fluid comprising particles, wherein the particles are charged or rechargeable and wherein the particles are adapted to absorb or reflect light, wherein an electromagnetic field between the plurality of electrodes provides electrophoretic motion of the particles toward or away from one of the plurality of electrodes. At least one current sensing circuit is connected to one of the plurality of electrodes, the current sensing circuit being configured to measure the current in the electrode to which it is connected when driven by a measurement signal temporarily applied during the measurement duration, wherein the measurement signal is an AC signal with a frequency of up to 100 Hz. During the measurement duration, at least one current sensing signal is received from at least one current sensing circuit, the at least one current sensing signal indicating the current in the corresponding electrode; a drive signal for the electrode is determined from the at least one current sensing signal and from the target transparency or target reflectivity; and when the measurement duration ends, the drive signal is transmitted to the optical modulator for applying a potential to the plurality of electrodes according to the drive signal.

22. A temporary or non-temporary computer-readable medium comprising data representing instructions that, when executed by a processor system, cause the processor system to perform the method of claim 21.

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