Electro-optical device having controlled electro-optical segments - Patents.com

Abstract

The electro-optical device comprises a first electrode in electrical communication with a power supply circuit. A second electrode is spaced from the first electrode and in electrical communication with the power supply circuit. An electro-optic medium is disposed between the first and second electrodes. At least one third electrode is disposed between the first and second electrodes and in electrical communication with one of the first and second electrodes via a switching circuit. The switching circuit is operable to control a current through the first electrode, the electro-optic medium and the second electrode.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates generally to electro-optic devices, and more particularly to electro-optic devices having individually controlled electro-optic segments. Summary of the Invention

[0002] In one aspect of the invention, an electro-optical device includes a first electrode in electrical communication with a power supply circuit. A second electrode is spaced from the first electrode and in electrical communication with the power supply circuit. An electro-optical medium is disposed between the first and second electrodes. At least one third electrode is disposed between the first and second electrodes and in electrical communication with one of the first and second electrodes via a switching circuit. The switching circuit is operable to control a current through the first electrode, the electro-optical medium, and the second electrode.

[0003] These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art with reference to the following specification, claims, and accompanying drawings.

[0004] The invention will now be described with reference to the following drawings. [Brief description of the drawings]

[0005] [Figure 1A] FIG. 1A is a perspective view of an automobile incorporating an electro-optical device of the present disclosure.

[0006] [Figure 1B] FIG. 1B is a perspective view of an aircraft incorporating the electro-optical device of the present disclosure.

[0007] [Figure 1C] FIG. 1C is a perspective view of a building incorporating an electro-optical device of the present disclosure.

[0008] [Diagram 2] FIG. 2 is an exploded view of the electro-optical device of the present disclosure.

[0009] [Diagram 3] FIG. 3 is a cross-sectional view of the electro-optical device of FIG.

[0010] [Figure 4] FIG. 4 is a schematic diagram of the electro-optical device of FIG. 2 in electrical communication with a control circuit.

[0011] [Diagram 5] FIG. 5 is a partial perspective cross-sectional view of the switching layer of the electro-optical device of FIG.

[0012] [Figure 6] FIG. 6 is a cross-sectional view of the electro-optic device of FIG. 2 incorporating two switching layers.

[0013] [Figure 7] FIG. 7 is a schematic diagram of the electro-optical device of FIG. 6 in electrical communication with a control circuit.

[0014] [Figure 8] FIG. 8 is an exploded view of an electro-optical device according to one embodiment of the present disclosure.

[0015] [Figure 9] FIG. 9 is a top view of an electro-optic device incorporating an array of electro-optic segments.

[0016] [Figure 10] FIG. 10 is a partial cross-sectional view of the electro-optical device of FIG.

[0017] [Figure 11] FIG. 11 is a partial perspective cross-sectional view of the switching layer of the electro-optical device of FIG.

[0018] [Figure 12] FIG. 12 is a schematic diagram of an electro-optic device in electrical communication with a control circuit.

[0019] [Figure 13] FIG. 13 is a schematic diagram of the electro-optical device of FIG. 10 in electrical communication with a control circuit.

[0020] [Figure 14] FIG. 14 is a schematic diagram of an electro-optical device in electrical communication with analog components of a control circuit.

[0021] [Figure 15] FIG. 15 is a schematic diagram of a power supply circuit for an electro-optical device according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] For purposes of description herein, the terms "upper", "lower", "right", "left", "rear", "front", "vertical", "horizontal", and derivatives thereof, refer to the disclosure associated with FIG. 1A. Unless otherwise stated, the term "front" refers to a surface of the device closer to the person intended to view the device, and the term "rear" refers to a surface of the device further away from the person intended to view the device. However, it should be understood that the invention may assume various alternative orientations, unless expressly specified to the contrary. It should also be understood that the specific devices and processes illustrated in the accompanying drawings and / or described in the following specification are merely exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

[0023] The terms "including," "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements may include not only those elements, but other elements not expressly listed or inherent in such process, method, article, or apparatus. An element preceded by "comprises a..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that comprises that element, without further constraints.

[0024] As defined herein, when used with respect to electrical properties, optical properties (e.g., light transmittance), etc., "substantially" may mean within 10% of a target state (e.g., 100%) in some embodiments. In other embodiments, "substantially" may mean within 5 percent of an ideal state. In further embodiments, "substantially" may mean within 3 percent of an ideal state. In yet other embodiments, "substantially" may mean within 1 percent of an ideal state. As an example, "opaque" may have an ideal state of about 0% light transmittance, while "transparent" may have an ideal state of about 100% light transmittance.

[0025] The order in which the surfaces of sequentially arranged structural elements of an assembly (such as substrates made of glass or other translucent materials) are viewed is the order in which these surfaces are referred to in ascending order as a first surface, a second surface, a third surface, and other surfaces, if present. Thus, in general, the surfaces of structural elements (e.g., equipment) of one embodiment of the invention are labeled numerically starting with a surface that is closest to a viewer or user of the assembly, corresponding to a top or front portion of the window assembly, and ending with a surface that is distal to the user, corresponding to a bottom or rear portion of the assembly. Thus, the term "rear" refers to a position in space following something else, suggesting that one element or something is behind another element when viewed from the front of the window assembly. Similarly, the term "front" refers to a forward location or position relative to a particular element when viewed from the front of the assembly.

[0026] According to some aspects of the present disclosure, electro-optical devices with improved responsiveness are disclosed. For example, the electro-optical device may include an electro-optical element divided into multiple electro-optical segments that can be individually controlled. The individualized control may prevent and / or limit the electro-optical device from producing an iridescence effect (i.e., darkening of the periphery of the electro-optical device before darkening of the center of the electro-optical device). Furthermore, the electro-optical device of the present disclosure may provide a cost-effective construction by reducing the depth of the conductive material applied to the substrate of the electro-optical element. Furthermore, the electro-optical device may provide a reduced busbar footprint on the electrodes of the electro-optical element. These reductions may generally be due to fine control over the electrical qualities (e.g., voltage, current) applied to the electro-optical device.

[0027] The electro-optical device may also provide single-sided power connections to the electro-optical elements with individualized control. More specifically, power may be provided to individual electro-optical segments of the electro-optical device such that a high voltage (e.g., 6-10V) may be provided to the electro-optical device without damaging the components of the electro-optical device. The high voltage may be any voltage operable to power a segment of the electro-optical device (e.g., 0.7V-1.2V) and / or any voltage operable to power multiple electro-optical segments (e.g., greater than about 1V). The high voltage may not be limited to a particular range of voltages. The voltage ranges described herein are intended to be exemplary and / or non-limiting. For example, the high voltage may be a minimum threshold voltage for powering the electro-optical segments to limit power consumption of the electro-optical device. In some arrangements, the supply voltage is dynamic and / or adjustable via manual or programmatic control. Optionally, a ground or negative power rail may be provided to improve clearing performance or to allow the drive voltage to be reduced for localized regions. A high voltage can be stepped down for each electro-optical segment. A high voltage can also mitigate voltage drop problems caused by the inherent resistivity of conductive materials that may be used in electro-optical devices. Additionally, the electro-optical devices of the present disclosure can provide faster and more uniform darkening and clearing of electro-optical cells by providing an array of individually controlled electro-optical segments.

[0028] 1A-1C, various embodiments of an electro-optical device 10 are incorporated with one or more structures 12. For example, FIG. 1A illustrates an automobile 12a that employs one or more electro-optical devices 10 in the form of an interior rearview mirror 13, a window 14, and / or an exterior rearview mirror 16. FIG. 1B illustrates an aircraft 12b that employs one or more electro-optical devices 10 in the form of a window 14. FIG. 1C illustrates a building 12c that employs one or more electro-optical devices 10 in the form of a window 14.

[0029] The window 14 may be configured to provide a physical barrier between the two regions and may be operable to allow variable transmission of light between the two regions. The window 14 may take various forms, such as a building window, a vehicle windshield, a side vehicle window, a rear vehicle window, a sunroof window, etc. The exterior rearview mirror 16 may be coupled to the exterior of the automobile 12a configured to provide the viewer with a field of view capturing the rear or sides of the vehicle 12a. The interior rearview mirror 13 may be a device within the automobile configured to provide the viewer with a field of view that includes the rear exterior of the automobile 12a. The interior rearview mirror 13 and the exterior rearview mirror 16 may be variably transmissive to minimize glare.

[0030] 2-4, an electro-optical device 10 incorporating electrical switching and control components is provided. With respect to the physical structure of the electro-optical device 10, a first electrode 22 is electrically connected to a power supply circuit 24. A second electrode 26 may be spaced apart from the first electrode 22 and electrically connected to the power supply circuit 24. An electro-optical medium 28 may be disposed between the first electrode 22 and the second electrode 26. At least one third electrode 30 (e.g., an intermediate electrode 30) may be disposed between the first electrode 22 and the second electrode 26. As shown in FIG. 2, the intermediate electrode 30 may be electrically connected to one of the first electrode 22 and / or the second electrode 26 via a switching circuit 32. The switching circuit 32 may be operable to control the current through the first electrode 22, the electro-optical medium 28, and the second electrode 26. The intermediate electrode 30 may be disposed towards a first portion 33a (e.g., an upper portion) of the electro-optical device 10. The electro-optical device 10 may lack an intermediate electrode 30 disposed toward a second portion 33b (e.g., a bottom portion) of the electro-optical device 10. In such a configuration, the first portion 33a may be referred to as an "active plate" due to the individual control and / or monitoring of electrical parameters of the first portion 33a, and the second portion 33b may be referred to as a "passive plate" due to the lack of individual control and / or monitoring of electrical parameters of the second portion 33b.

[0031] The electro-optical device 10 may extend along a length L of the electro-optical device 10 between a first end 34 and a second end 36 opposite the first end 34. The electro-optical device 10 may also have a thickness T extending between a first substrate 38 and a second substrate 40 of the electro-optical device 10. An electro-optical element 42 may be disposed between the first substrate 38 and the second substrate 40 of the electro-optical device 10. The electro-optical element 42 may be generally formed from the second electrode 26, the electro-optical medium 28, and the intermediate electrode 30. The term electro-optical element may be used herein primarily to refer to the electrical characterization of the illustrated physical structure and is not intended to be limited to any particular portion of the electrodes 22, 26, 30 or the electro-optical medium 28. It is further contemplated that one or more of the electro-optical elements 42 may include, or otherwise be referred to as, an electrochromic cell.

[0032] Each of the first substrate 38 and the second substrate 40 may extend between an outer surface 44 and an inner surface 46. The electro-optic element 42 may be sandwiched between an inner surface 46 of the first substrate 38 and the second substrate 40. Electrical connectors 48 (e.g., bus bars) may be provided at one or both ends 34, 36 of the electro-optic device 10 to provide a power connection to the electro-optic device 10. The electrical connectors 48 may additionally or alternatively be positioned alongside edges 49 of the electro-optic device 10 on the first electrodes 22 and second electrodes 26.

[0033] More specifically, with reference to FIG. 3, the intermediate electrode 30 and the second electrode 26 define a cavity 50 extending therebetween for receiving the electro-optic medium 28. The electro-optic medium 28 can be an electro-optic fluid of a substantially transparent material that is electrically conductive. In at least one embodiment, the electro-optic medium 28 is an electrochromic medium that includes at least one solvent, at least one anodic material, and at least one cathodic material. Typically, the anodic and cathodic materials are both electroactive and at least one is electrochromic. The first electrode 22 and the second electrode 26 can be surface mounted to the inner surfaces 46 of the first substrate 38 and the second substrate 40, and can be solid rather than gel-like. The intermediate electrode 30 can have a similar composition (indium tin oxide (ITO)) with a thickness less than either or both of the first and second electrodes 22, 26. Although ITO is specified in this embodiment, a variety of transparent conductive materials can be used. The electro-optic medium 28 may include an electrochromic material that may change color when an electrical potential and / or current is applied across the electro-optic medium 28. By using selectively transparent materials for various components of the electro-optic device 10, the electro-optic device 10 may be selectively darkened (e.g., have controlled light transmission) in response to electrical parameters applied to the electrodes 22, 26, 30.

[0034] Continuing to refer to FIG. 3 , the cavity 50 may be sealed via one or more barriers 52, 54 disposed between the third electrode 30 and the second electrode 26. The barriers may include edge barriers 54, along with intermediate barriers 52 disposed in the cavities 50. The edge barriers 54 may be disposed along the periphery of the electro-optic device 10 to prevent the electro-optic medium 28 from leaking out of the cavities 50 and / or to prevent the electro-optic medium 28 from being exposed to atmospheric conditions. The intermediate barriers 54 may physically and / or electrically separate portions of the electro-optic medium 28 into the cavities 50. In this manner, the intermediate barriers 52 may separate the electro-optic device 10 into the electro-optic elements 42, the latter of which may be independently / individually controlled. In addition to providing improved control, the barriers 52, 54 may provide stability to the electro-optic device 10. The barriers 52, 54 may be formed of epoxy resin and may be non-conductive.

[0035] 2 and 3, the switching circuit 32 may be disposed in a switching layer 56 that interposes the intermediate electrode 30 and one or both of the first electrode 22 and the second electrode 26. As shown, the switching layer 56 may be sandwiched between the first electrode 22 and the intermediate electrode 30. Effectively, the switching layer 56 may control whether and how much power is supplied to the intermediate electrode 30 by adjusting the switching circuit 32. The switching layer 56 may have a shape and continuity similar to that of the backplane electrodes (e.g., the first electrode 22 and the second electrode 26), although the specific shape and distribution of the switching layer 56 is not limited to this shape. For example, the switching layer 56 may be web-shaped or may be formed only along the side edges 49 or the middle portion of the electro-optical element 42.

[0036] 3, a flexible circuit 58 may be provided to carry electrical signals between the electro-optical components and off-board circuitry. The flexible circuit 58 may be in electrical communication with the electro-optical device 10 via a conductive connection 60 having a plurality of conductors 62 that are electrically insulated from one another. The conductive connection 60 may include an anisotropic conductive film (ACF) having an epoxy acrylic adhesive 64 and conductive beads 66 suspended within the adhesive 64, where the adhesive 64 may be non-conductive. The beads 66 may provide electrical communication between the plurality of conductors 62 and one or more conductive traces 68 within the electro-optical device 10. For example, the electro-optical device 10 may include a conductive trace 68 disposed on or embedded within the first or second electrodes 22, 26, the switching layer 56, or another portion of the electro-optical device 10. In a more specific example, one conductive trace 68 may couple a global voltage V to the first electrode 22 or the second electrode 26 (e.g., an ITO backplane). G , and other conductive traces 68 may be formed in the switching layer 56 for connection to the switching circuitry 32. In this manner, the flexible circuit 58 may allow the electrical properties of the electro-optic device 10 to be controlled at a location remote from the electro-optic components.

[0037] 4, the electro-optical device 10 is illustrated generally with a control circuit 70 in electrical communication with the electro-optical element 42. For clarity, the electro-optical device 10 may be referred to as having a visible portion 71a (e.g., "glass") and a hidden portion 71b (e.g., a feature spaced from the window assembly or a feature disposed on the window assembly but hidden along the periphery of the window assembly). A dividing line 72 indicates one possible configuration of the location of the visible portion 71a relative to the location of the hidden portion 71b. As illustrated, the left side of the dividing line 72 may represent the hidden portion 71b and the right side of the dividing line 72 may represent the visible portion 71a. The specific locations of the various components of the electro-optical device 10 may depend on the size, shape and / or level of light opacity of each component. For example, components having transparent, semi-transparent or semi-transmissive properties may be disposed with the window assembly, while large and / or substantially opaque components may be positioned within the hidden portion 71b. In this manner, an electro-optic device 10 is provided that can be substantially transparent while being electrically controlled via external components.

[0038] The control circuit 70 generally achieves control of the electro-optical element 42 by controlling the power supply circuit 24 and / or the switching circuit 32. More specifically, the control circuit 70 may include a controller 73 that receives a voltage or current signal corresponding to the voltage or current associated with the electrodes 22, 26, 30. The controller 73 may output a control signal to the switching circuit 32 and / or the power supply circuit 24 to adjust the voltage or current applied to the electro-optical element 42. The control signal may be generated based on the voltage and current signals according to programmed instructions stored in the controller 73. For example, if the voltage between the intermediate electrode 30 and the second electrode 26 (i.e., the voltage across the electro-optical element 42) is less than a target voltage across the electro-optical element 42, the controller 73 may control the switching circuit 32 to provide a greater voltage to the intermediate electrode 30. In this manner, the voltage across the electro-optical element 42 may be increased to the target voltage. In embodiments described further herein, the controller 73 may control the switching circuit 32 to provide a greater or lesser voltage to the second electrode 26 (see at least FIG. 7).

[0039] As represented diagrammatically in FIG. 4, the electro-optical element 42 may have a first electrical approximation of a resistor R in parallel with a resistor-capacitor (RC) series circuit. Although approximated as shown in FIG. 4, the electro-optical element 42 may also have a second electrical approximation of a current source in parallel with three parallel RC circuits. The second electrical approximation may be an accurate model when the electro-optical element 42 is an electrochromic cell (EC cell). For example, an EC cell may store more charge than a parallel plate capacitor. The electrical approximation of the electro-optical element 42 may depend on the particular quality of the material used in the electro-optical medium 28 (e.g., electro-optical fluid) and the quality and / or type of material utilized in the construction of the electrodes 22, 26, 30. Additionally, the electrical characteristics of the electro-optical element 42 may be transient (e.g., dependent on the transmittance state or temperature of the electro-optical element 42). Additional factors that affect the operation of the device 10 may include the age of the electro-optical device 10 or environmental conditions (e.g., temperature differences between the interior and exterior of a vehicle). At least one temperature sensor may be provided in the electro-optical device 10 to monitor the temperature of the electro-optical device 10. As will be described in further detail, the at least one temperature sensor may include multiple temperature sensors disposed within and / or around the periphery of the electro-optical device 10. The at least one temperature sensor may include a bandgap voltage reference circuit or other circuitry operable to detect a temperature or temperature change associated with the electro-optical device 10.

[0040] 4, the electro-optical element 42 may be in communication with the power supply circuit 24 via a first node 74 and a second node 75. The power supply circuit 24 provides a global voltage V across the first node 74 and the second node 75. GThe power supply circuit 24 may be operable to apply a voltage Vcc to the power supply circuit 24 when a load (e.g., the electro-optical element 42) is in communication with both the first node 74 and the second node 75. To better control the flow of current to or from the electro-optical element 42, the switching circuit 32 may include a first switching circuit 76 electrically interposing the first node 74 and a third node 77 electrically connected to the intermediate electrode 30. In this manner, the switching circuit 32 may selectively allow current to flow between the first node 74 and the third node 77. In some embodiments described further herein, the switching circuit 32 may also include a second switching circuit 78 electrically connecting a fourth node 80 electrically connected to the second electrode 26 to the power supply circuit 24. As exemplarily shown in FIG. 4, the second switching circuit 78 may be omitted and the current through and / or the voltage across the electro-optical element 42 may be controlled by the first switching circuit 76. This configuration may generally correspond to the "passive plate" arrangement previously described.

[0041] In the illustrated exemplary embodiment, at least one first resistor 92 is shown in electrical series connection with the first node 74, and at least one second resistor 94 is shown in electrical series connection with the second node 75. Each resistor 92, 94 functions as an electrical approximation of the inherent resistance characteristic of the first and second electrodes 22, 26, respectively. In general, it is contemplated that the inherent resistance of the electrodes 22, 26 increases as the distance from the power supply circuit 24 increases. This may result in a corresponding voltage drop across the length L or width of the electro-optical device 10. For example, ITO may have a resistance of 1 ohm per square millimeter. Thus, the control circuit 70 may monitor and control electrical parameters of the electrodes (e.g., the first and second electrodes 22, 26) or areas near the electrodes to maximize the uniformity of the electro-optical device 10.

[0042] Since the controller 73 may be a digital signal controller, the control circuitry 70 may include at least one converter module 96, 98, 100, 102 for converting electrical signals from one form to another. For example, the controller 73 may be operable to output and receive digital signals, while the switching circuitry 32 and / or some portions of the control circuitry 70 may operate in response to analog signals (e.g., potentials) and / or output analog signals. The converter modules 96, 98, 100, 102 may include digital-to-analog converters (DACs) and analog-to-digital converters (ADCs). The ADCs may be used to monitor various electrical parameters associated with the electro-optical device 10. For example, the first ADC 96 may be operable to receive the measured voltage via a first feedback node 104 in electrical communication with the first electrode 22. The second ADC 98 may be operable to receive the measured voltage via a second feedback node 106 in electrical communication with the intermediate electrode 30. A first DAC 100 may be used to control the power supply circuit 24, which may include one or more DC power supplies. It is generally contemplated that any other type of power supply may be used to generate power for the electro-optical element 42, such as a current driver or a voltage driver. A second DAC 102 may be used to control the switching circuit 32 via first and second drive nodes 108, 109. The power supply circuit 24 may be configured to set a voltage, such as 0V or a negative voltage, lower than the element voltage (e.g., the voltage across the electro-optical element 42) to discharge the electro-optical element 42 and optically clear it. In this manner, the flow of current through the electro-optical element 42 may be reversed and charge may be removed from the electro-optical element 42.

[0043] The control circuit 70 may include a number of control transistors 110, 112, 114 in electrical communication with a controller 73 via an integrated circuit (IC 116). A multiplexer 118 may be interposed between the controller 73 and the control transistors 110, 112, 114. Alternatively, the multiplexer 118 may be omitted and a selection signal may be communicated directly to each of the control transistors 110, 112, 114 via one or more selection nodes 119. In the illustrated example, the IC 116 may act as a DAC by processing one or more digital signals provided by the controller 73 to generate a selection signal, which may be an analog signal, and communicating the selection signal to the multiplexer 118 via the selection node 119. The selection signal may be controlled via a shift register that allows sequential selection of each output at high frequency. The multiplexer 118 may be operable to output a control signal via at least one control node 136 to one of the plurality of control transistors 110 , 112 , 114 based on the selection signal provided by the integrated circuit 116 .

[0044] Regarding a particular embodiment of the IC 116 of the present disclosure, the integrated circuit 116 may be a gate drive circuit. The IC 116 may be a source driver IC 116 (e.g., Novatek NT39411) for directly controlling the drive transistor 120 instead of the second DAC 102. As described in more detail with reference to FIGS. 8-13, the source driver IC 116 may have multiple outputs for simultaneously driving multiple electro-optical segments. The IC 116 may be mounted on the visible portion 71a (as shown) or on the hidden portion 71b. The IC 116 may include up to or at least 2000 digital-to-analog outputs for controlling multiple electro-optical elements 42 to monitor / control multiple points along a single electro-optical element 42. For example, the IC 116 may include multiple selection nodes 119, each selection node 119 associated with one electro-optical element 42. In this manner, the IC 116 may control hundreds or thousands of electro-optical elements 42 (or hundreds or thousands of electro-optical segments as discussed with reference to FIG. 9). One output (e.g., a select signal) may control a single multiplexer 118 that can control multiple control transistors 110, 112, 114. In general, it is contemplated that one or more of the functions of the multiplexer 118 may be incorporated into the IC 116. Alternatively, the functions of one or both of the IC 116 and the multiplexer 118 may be integrated with the controller 73 such that the controller 73 may directly control the switching circuitry 32 without the need for additional components. The IC 116 may include one or more shift registers that allow the IC 116 to cycle between control of the outputs of the IC 116.

[0045] More specifically, referring to the control circuit 70 shown in FIG. 4, a first control transistor 110 may be interposed between the first feedback node 104 and the first electrode 22. This arrangement may allow selective connection between the first feedback node 104 and the second electrode 26. A second control transistor 112 may be interposed between the second feedback node 106 and the intermediate electrode 30 to selectively connect the second feedback node 106 to the intermediate electrode 30. A third control transistor 114 may be interposed between the first drive node 108 and the second drive node 109 to control the first switching circuit 76 to electrically connect the second electrode 26 to the third electrode 30. The first and second control transistors 110, 112 may be operable to transmit analog signals between the controller 73 and the first electrode 22 and between the controller 73 and the intermediate electrode 30, respectively. Additionally, the third control transistor 114 may be operable to transfer digital signals between the controller 73 and the first switching circuit 76.

[0046] One example of how the control circuit 70 controls the transparency or darkening of the electro-optic element 42 is via activating or deactivating the drive transistor 120 of the switching circuit 32. As shown, the drive transistor 120 may be interposed between the first electrode 22 and the intermediate electrode 30. When the drive transistor 120 is open (e.g., the drive transistor 120 is deactivated), the drive transistor 120 may operate as a switch that prevents current from flowing between the first electrode 22 and the intermediate electrode 30. When the switch is closed (e.g., the drive transistor 120 is activated), current may flow between the first electrode 22 and the intermediate electrode 30, darkening the electro-optic element 42. The electro-optic element 42 may become transparent when current is prevented from flowing through the electro-optic medium 28. The electro-optic element 42 may become dark when current flows through the electro-optic medium 28.

[0047] Turning now to specific aspects of the drive transistor 120, the drive transistor 120 may have a first leg 122, a second leg 124, and a third leg 126. The third leg 126 may be operable to control a current between the first leg 122 and the second leg 124. The first leg 122 may be electrically connected to the first electrode 22, and the second leg 124 may be electrically connected to the intermediate electrode 30. The drive transistor 120 may be a field effect transistor (FET) having a source terminal corresponding to the first leg 122, a drain terminal corresponding to the second leg 124, and a gate terminal corresponding to the third leg 126. The FET may be a junction field effect transistor (JFET), an organic field effect transistor (OFET), or a metal oxide semiconductor field effect transistor (MOSFET), and may be controlled in response to a voltage across the drain and source terminals. Alternatively, the drive transistor 120 may be an insulated gate bipolar transistor (IGBT). Drive transistor 120 may be a bipolar junction transistor (BJT) having a collector terminal corresponding to first leg 122, an emitter terminal corresponding to second leg 124, and a base terminal corresponding to third leg 126. The BJT may be an NPN or PNP transistor and may be controlled in response to voltages across the base and emitter terminals. Operation of drive transistor 120 may be described in terms of a current flowing through and / or a voltage corresponding to third leg 126, and references to either a "current controlled" or "voltage controlled" type of transistor are merely illustrative and non-limiting.

[0048] In some embodiments, the drive transistor 120 and / or the plurality of control transistors 110, 112, 114 are thin film transistors (TFTs) disposed within the visible portion 71a. For example, the switching layer 56 may include the drive transistor 120 and / or the plurality of control transistors 110, 112, 114. The transistors 110, 112, 114, 120 may be substantially transparent and / or may include visible metal traces interconnecting with the intermediate electrodes 30 (FIG. 5). In some embodiments, the metal traces are not visually detectable from a distance (e.g., 15-50 cm) away from the electro-optical device 10. Thus, one or more of the transistors 110, 112, 114, 120 may be provided on the visible portion 71a.

[0049] Continuing to refer to FIG. 4, the third leg 126 of the drive transistor 120 may be in electrical communication with the third control transistor 114 via the second drive node 109. In this manner, control of the drive transistor 120 may originate from the controller 73. In operation, the controller 73 may communicate a first digital signal via the first output node 130. The first digital signal may be converted to a voltage or current via the second DAC 102. The controller 73 may further be operable to communicate a second digital signal to the IC 116 via the second output node 132. The second digital signal may cause the IC 116 to output a select signal to the multiplexer 118 via the select node 119. The select signal may cause the multiplexer 118 to output a control signal to the third control transistor 114 via the control node 136. The control signal may be an analog signal operable to control the third control transistor 114 to generate a voltage on the third leg 126 of the drive transistor 120 and / or allow a current to flow from the second DAC 102 through the first and second drive nodes 108, 109 to the third leg 126 of the drive transistor 120. In this manner, the controller 73 may be operable to control the drive transistor 120 to apply a current or a voltage to the electro-optical element 42.

[0050] The voltage / current at the third leg 126 of the drive transistor 120 may cause the drive transistor 120 to allow current to flow from the first leg 122 (corresponding to the second electrode 26) to the second leg 124 (corresponding to the intermediate electrode 30). The first and second control transistors 110, 112 may operate similarly to the third control transistor 114. For example, the first control transistor 110 may operate to provide voltage and / or current measurement data to the controller 73 corresponding to the first electrode 22. The second control transistor 112 may operate to provide voltage and / or current measurement data to the controller 73 corresponding to the intermediate electrode 30. The measurement data may be a result of processing analog signals via the first and second ADCs 96, 98. According to some embodiments, the controller 73 may directly control the drive transistor 120. For example, the second DAC 102 may be operable as a simple source driver for the drive transistor 120 such that the third control transistor 114 is omitted. In general, it is contemplated that both the gate driver IC 116 and the source driver IC 116 may be used simultaneously. Either or both of the gate and source driver ICs 116 may be a display driver integrated circuit (DDIC).

[0051] A capacitor 138 may be provided in the electro-optical device 10 to maintain or hold a target voltage or target current of the electro-optical element 42. For example, the capacitor 138 may provide a sample and hold function after the electro-optical element 42 or multiple electro-optical segments are scanned and the reference voltage is monitored / measured by the control circuit 70. In one embodiment, the capacitor 138 stores an analog voltage during scanning of multiple voltages across multiple electro-optical segments and / or while the controller 73 processes the voltage data to control the DAC 102. The capacitor 138 may be interposed between the second electrode 26 and the second drive node 109 and may control the voltage and / or current between the first electrode 22 and the second drive node 109. For example, the capacitor 138 may charge and / or discharge a current based on a voltage difference between the second drive node 109 and the first electrode 22. In operation, capacitor 138 may hold the voltage at the gate terminal (i.e., third leg 126) of drive transistor 120 while multiplexer 118 cycles control of control node 136. In other words, capacitor 138 may allow drive transistor 120 to remain activated by discharging its electrical energy when the potential is removed from capacitor 138 after the analog signal at second drive node 109 is removed.

[0052] 4, the drive transistor 120 may be activated / deactivated (activated / deactivated) at a particular frequency with an average activation time, resulting in an average current or voltage on the third leg 126 at a particular rate. The controller 73, or another portion of the control circuit 70, may be operable to apply pulse width modulation (PWM) to the third leg 126 of the drive transistor 120. For example, the multiplexer 118 may be operable to pulse the third control transistor 114 on / off at a particular rate while the first drive node 108 maintains a constant signal / voltage. In this manner, the drive transistor 120 may be selectively activated at a frequency that matches or otherwise corresponds to the frequency at which the third control transistor 114 is activated. The first node 74 may provide a relatively high voltage (e.g., 0.8V to 6V) such that the duty cycle of the drive transistor 120 is operable to control the voltage applied to the intermediate electrode 30 between 0V to 6V. For example, a 50 percent duty cycle may result in a voltage of 3V being provided across drive transistor 120. However, due to the resistance of the electrodes (e.g., the ITO of the backplane (resistors 92, 94)), voltage drops may result in the same duty cycle (i.e., 50%) producing a voltage less than 3V.

[0053] In some embodiments, the drive transistor 120 may be controlled to achieve a voltage drop of 0.2-0.8V across the electro-optical element 42. To achieve this voltage drop, the resistance of the first electrode 22 and the second electrode 26 may be monitored or otherwise accounted for in the pre-programmed algorithm of the controller 73. For example, because there may be some loss of power along the ITO backplane (e.g., the first electrode 22 and the second electrode 26), the rate at which the drive transistor 120 is activated may vary depending on environmental conditions such as heat, sunlight, and / or activation of one or more other circuits of the electro-optical device 10. The update rate of the control circuit 70, i.e., the frequency at which the controller 73 receives data and generates an output, may be 10Hz in some embodiments. Individual control of the electro-optical elements 42 may allow the electro-optical elements 42 not to exceed a voltage drop threshold (e.g., 1.2V or 1.4V). The drive transistor 120 may employ amorphous silicon to limit leakage through the drive transistor 120 when light passes through the electro-optical device 10 .

[0054] Due to the resistive nature of the ITO coating, the potential corresponding to the electrodes (e.g., first, second and intermediate electrodes 22, 26, 30) may decrease as the size (e.g., length L, thickness, width, etc.) of the electro-optical device 10 increases and / or as the distance of the electro-optical device 10 from the power supply circuit 24 increases. In general, the voltage drop over distance from the power supply may be approximated by half the product of (i) the square of the distance from the electrical connector 48 (e.g., bus bar), (ii) the resistance of the ITO coating per unit distance, and (iii) the current loss per area of ​​the electro-optical element 42. Due to the exponential relationship of the voltage drop to the distance (e.g., length L) from the bus bar, increasing the distance by a factor (e.g., 2) results in a voltage drop that is the square of that factor (e.g., 4). Thus, monitoring the voltage at several points along the electrodes (eg, the first, second and intermediate electrodes 22, 26, 30) may allow the controller 73 to control each drive transistor 120 of the electro-optical element 42 individually.

[0055] In various embodiments, the controller 73 may be operable to perform various methods of controlling the current through the electro-optical element 42. The controller 73 may be operable to receive electrical feedback (e.g., voltage, current, etc.) corresponding to one or more of the first electrode 22, the second electrode 26, and the intermediate electrode 30. The controller 73 may be operable to control the switching circuit 32 via the integrated circuit 116 and / or other control circuitry 70 based on the electrical information / feedback. In particular, the controller 73 may be operable to control the drive transistor 120 to pass current therethrough to activate the electro-optical element 42. The controller 73 may further be operable to control the power supply circuit 24 based on the electrical information. As an example, the controller 73 may control the power supply circuit 24 to reverse the polarity of the power supply circuit 24 to pass current from the second electrode 26 to the first electrode 22. An example of a power inverter circuit as further described herein is shown in FIG. 15. Additionally or alternatively, the controller 73 may control the power supply circuit 24 to reduce its output voltage.

[0056] Controlling the current through the electro-optic element 42 may be a closed loop operation, in part, via feedback nodes 104, 106. By monitoring the voltage and / or current at various points within the electro-optic device 10, control of the switching circuit 32 (e.g., drive transistor 120) may be adjusted to achieve the desired characteristics of the electro-optic cell (e.g., electro-optic element 42). In embodiments incorporating at least one temperature sensor, the temperature gradient of the electro-optic device 10 may be monitored by the control circuit 70 to allow further individualized control of the electro-optic element 42 or multiple electro-optic segments. In some embodiments, the transparency of the electro-optic medium 28 may be controlled using a voltage across the electro-optic element 42 that is within the range of about 0.2 volts to about 0.8 volts. Continuing with this example, generating a 0.8 volt signal may cause the electrochromic fluid in the electro-optic medium 28 to darken, and generating a 0.2 volt signal may cause the electrochromic fluid in the electro-optic medium 28 to become transparent. Due to the size and shape of the electrodes 22, 26, 30 and the location where the voltage and / or current is applied, a gradient distribution of the electro-optic medium 28 may be provided. Additionally, as previously discussed, the thickness of the ITO may affect the resistance of the ITO and therefore the voltage and / or current across the electro-optic element 42. According to some embodiments, the thickness of the ITO may be about 1500 nm. In other configurations, the thickness of the ITO may be within a thickness range of about 100 nm to about 250 nm.

[0057] Closed loop voltage control can allow for voltage variations across the ITO layer, thereby reducing the transistor's sensitivity to light and temperature variations. In other words, changes in electrical properties (e.g., voltage) due to light or temperature variations can be detected, so that the power applied to the electro-optical element 42 can be controlled so as not to exceed a voltage or current that could damage the electro-optical element 42. In some embodiments, the drive transistor 120 can be turned off for a period of time, and the feedback nodes 104, 106 can be monitored during that period. Because no current flows through the electrodes (e.g., the first electrode 22 and the intermediate electrode 30) while the voltage across the electro-optical element 42 is monitored (except for the discharge of the capacitor 138), accurate voltage measurements can be collected.

[0058] 5, one possible location of the drive transistor 120 is generally shown with the gap (e.g., cavity 142) as shown. The drive transistor 120 and / or various electrical components of the switching circuitry may be disposed within an insulating substrate 140 of the switching layer 56. The insulating substrate 140 may define a cavity 142 for receiving the switching circuitry 32. The cavity 142 may have an open top 144 and / or an open bottom 146 thereby extending through a depth D of the insulating substrate 140. The open top 144 may expose the cavity 142 to the first electrode 22 such that a conductive material may extend between the first electrode 22 and at least a portion of the cavity 142. Similarly, the open bottom 146 may extend between the intermediate electrode 30 and at least a portion of the cavity 142. In this manner, the switching circuitry (e.g., drive transistor 120) may be in electrical communication with the second electrode 26 and the intermediate electrode 30. More specifically, the drive transistor 120 may be disposed adjacent an open top 144, and the second leg 124 of the drive transistor 120 may be disposed adjacent an open bottom 146. The insulating substrate 140 may be formed of a substantially transparent material, such as silicon dioxide.

[0059] 5, the insulating substrate 140 may include a plurality of electrode traces 160, 162, 164 for electrically connecting a portion of the cavity 142 with one or more electrical devices spaced from the electro-optical element 42. For example, the electrode traces 160, 162, 164 may be part of the control circuitry 70 and may connect from an outer surface 153 of the switching layer 56, such as an outer edge of the electro-optical device 10, to one or more of the IC 116, the controller 73, the multiplexer 118, the control transistors 110, 112, 114, etc. The plurality of electrode traces 160, 162, 164 may be completely surrounded by the insulating substrate 140 as shown, or may be disposed on the upper surface 154 and / or the lower surface 156 of the switching layer 56 (e.g., in notches extending into the insulating substrate 140). The plurality of electrode traces 160, 162, 164 may include a first electrode trace 160, a second electrode trace 162, and a third electrode trace 164, each extending along a non-intersecting path.

[0060] In one embodiment, the first electrode trace 160 may interconnect the first control transistor 110 and the second electrode 26. The second electrode trace 162 may interconnect the second control transistor 112 and the middle electrode 30. The third electrode trace 164 may interconnect the third control transistor 114 of the drive transistor 120 and the third leg 126 of the drive transistor 120. The electrode traces 160, 162, 164 may be formed of ITO or may be metal wires or metal coatings with a thin thickness (e.g., 0.1 mm to 5 mm) such that the electro-optical element 42 remains substantially transparent. Although not shown in detail, at least one temperature sensor may also be disposed within the insulating back portion 140 in the cavity 142 or a separate cavity. The electro-optical device 10 may include additional electrode traces to allow electrical signals to be transmitted from at least one temperature sensor, a voltage and / or current corresponding to a temperature reading, to the control circuit 70, for example, the at least one temperature sensor comprised of one or more TFTs to provide individual control based on a temperature gradient across the electro-optical device 10 while allowing substantial transparency of the electro-optical device 10.

[0061] 6 and 7, an electro-optic device 10 having two active plates is generally illustrated. The intermediate electrode 30 described above may include a first intermediate electrode 166 and a second intermediate electrode 168. An electro-optic medium 28 may be disposed between the first and second intermediate electrodes 166, 168. In this configuration, the pair of intermediate electrodes 166, 168 and the electro-optic medium 28 form an electro-optic element 42, rather than a single intermediate electrode 166, 168 and first or second electrode 22, 26 as shown with reference to the previous figures. As illustrated, the electro-optic device 10 may include a first switching layer 170 sandwiched between the first electrode 22 and the first intermediate electrode 166. A second switching layer 172 may be sandwiched between the second electrode 26 and the second intermediate electrode 168. Similar to the single switching layer 56, the first and second switching layers 170, 172 may include features described as part of the switching layer 56 (ie, switching circuits 76, 78, drive transistor 120, etc.).

[0062] As particularly shown in FIG. 7, the switching circuit 32 may include a first drive transistor 174 and a second drive transistor 176. The first drive transistor 174 may be operable to control an electrical connection between the first electrode 22 and the first intermediate electrode 166. The second drive transistor 176 may be operable to control an electrical connection between the second electrode 26 and the second intermediate electrode 168. The first and second switching circuits 76, 78 may be controlled via the same control circuit 70 or separate control circuits (i.e., first and second control circuits). The first and second control circuits are shown generally at 70a and 70b in FIG. 7. Although shown as separate components, the first and second control circuits 70a, 70b may be implemented as a single control device (e.g., IC 116 in FIG. 12). As an example, each of the control circuits 70a, 70b may include a combination of the aforementioned electrical components, such as IC 116, multiplexer 118, and control transistors 110, 112, 114. The first control circuit 70a and the second control circuit 70b may be independently controlled by the controller 73. In this manner, the controller 73 may control the first control circuit 70a differently than the second control circuit 70b. For example, the second drive transistor 176 may be controlled to pulse at a slower or faster rate than the first drive transistor 174, or vice versa.

[0063] Providing the second switching layer 172 may allow finer control of the potential, and therefore the current, across the electro-optical cell 42. Because the state of the electro-optical element 42 may depend on the relative voltages of the first and second intermediate electrodes 166, 168, monitoring the voltage on one or both sides of the electro-optical element 42 may allow the controller 73 to provide a more accurate response. Furthermore, the inclusion of the second drive transistor 176 may provide even greater precision in achieving the desired current or voltage change.

[0064] 8-13, various embodiments of the electro-optic device 10 are illustrated that include a plurality of intermediate electrodes 178 forming a plurality of electro-optic segments 179. The plurality of electro-optic segments 179 may be arranged in an array 180 having a plurality of rows 182 and a plurality of columns 184. Both single active plate (FIGS. 8 and 12) and dual active plate (FIGS. 10 and 13) embodiments are illustrated with a plurality of electro-optic segments 179. As described below, the electro-optic segments 179 may be referred to as individual electro-optic elements 42 or as portions of a single electro-optic element 42. For example, the intermediate barrier 52 may be omitted and the electro-optic segments 179 may operate as portions of a single electro-optic element 42 that may have individually controlled components (as shown in the figures). Alternatively, the intermediate barrier 52 may divide the electro-optic medium 28 into a plurality of portions, with one electro-optic segment 179 associated with each portion. The plurality of intermediate barriers 52 may be spaced apart at a distance different from the space between the plurality of electro-optic segments 179. In this manner, one electro-optic segment 179 may overlap two or more separate portions of electro-optic medium 28 (eg, through the overlap of electrodes 22, 26, 178).

[0065] As exemplarily illustrated in FIGS. 8 and 9 , the array 180 may comprise a 6×6 grid of 36 electro-optical segments 179 and the same or different number of drive transistors 120. In this manner, the desired transmittance of the individual portions of the electro-optical elements 42 may be controlled to create a desired shape and / or gradient of the electro-optical device 10. For example, it is generally contemplated by this disclosure that the electro-optical device 10 may include any number (e.g., tens, hundreds, millions, etc.) of electro-optical segments 179 within the single electro-optical device 10, as described above. The optical resolution of the shape formed by the electro-optical segments 179 may depend on the number of segments within the electro-optical device 10. The resolution may also depend on the size and / or spacing between the electro-optical segments 179.

[0066] The size and shape of the electro-optical segments 179 may be uniform or non-uniform. For example, some electro-optical segments 179 may be elongated and / or shaped as regular polygons (e.g., hexagons, squares), while other electro-optical segments 179 may be shaped as irregular polygons. In some cases, one or more of the electro-optical segments 179 may form a curved mark, logo, or the like. In this manner, the electro-optical device 10 may be operable to display a mark by controlling the electro-optical medium 28 to transmit light within the mark and block light outside the mark, or vice versa. Due to differences in size and / or shape of the electro-optical segments 179 / intermediate electrodes 166, 168 combined with individualized control of the drive transistors 120, specific gradients or patterns may be formed within the electro-optical device 10.

[0067] More specifically, with reference to Figures 9 and 10, multiple portions of the control circuitry 70 may be positioned on one or both of the substrates 38, 40. For example, the power circuitry 24 and / or the control circuitry 70 (e.g., one or more of the converter modules 96, 98, 100, 102) may be positioned in the hidden portion 71b along the periphery of the electro-optical device 10. The power circuitry 24 and / or the control circuitry 70 may connect to the electro-optical segments 179 via sense and drive buses (generally indicated by arrows in Figure 9). The sense and drive buses may be provided via electrode traces 160, 162, 164 as previously described. The electrode traces 160, 162, 164 may be formed in the insulating portions of the switching layer 56 between the electro-optical segments 179. In this manner, the electrode traces 160, 162, 164 remain electrically isolated from all of the electro-optical segments 179 except for the particular electro-optical segments 179 that are controlled / monitored via the control circuitry 70.

[0068] 10, a cross-sectional view of a portion of an electro-optic device 10 is illustrated showing a pair of adjacent electro-optic segments 179 (e.g., a first electro-optic segment 186 and a second electro-optic segment 188). The first and second electro-optic segments 186, 188 may be spaced apart from one another. The light transmittance of the first electro-optic segment 186 and the second electro-optic segment 188 may be individually controlled to achieve a desired pattern or rate of clearing / darkening of the electro-optic device 10. It is generally contemplated that the first electro-optic segment 186 may be in parallel with the second electro-optic segment 188. Although a dual active plate configuration is illustrated in the exemplary diagram, it is generally contemplated that the electro-optic segments 186, 188 may be part of an electro-optic device 10 having a single active plate without departing from this disclosure.

[0069] As similarly described with respect to a configuration having two intermediate electrodes 166, 168 in a single electro-optical element 42 (e.g., FIG. 6), the first switching layer 170 may be disposed between the first electrode 22 and the pair of first intermediate electrodes 166a, 166b. The first switching layer 170 may include a first switching circuit 76 for controlling the first electro-optical segment 186. The first switching layer 170 may also include a third switching circuit 190 (see FIGS. 12 and 13) for controlling the second electro-optical segment 188. Similarly, the second switching layer 172 may be disposed between the second electrode 26 and the pair of second intermediate electrodes 168a, 168b. The second switching layer 172 may include a second switching circuit 78 for controlling the first electro-optical segment 186. The second switching layer 172 may also include a fourth switching circuit 192 for controlling the second electro-optical segment 188. Each of the switching circuits 76, 78, 190, 192 may be controlled as a group or individually by employing a combination of the various electrical components previously described (e.g., controller 73, control circuit 70, multiplexer 118, control transistors 110, 112, 114, IC 116, DACs 100, 102, ADCs 96, 98, etc.) These switching circuits 76, 78, 190, 192 are shown generally in FIG.

[0070] 8 and 9, one or more electro-optical segments 179 may form an array 180 of electro-optical segments 179. Although the rows 182 and columns 184 are shown in a rectangular grid-like configuration, any shape and / or arrangement of the array 180 may be formed. For example, the array 180 may be arranged in a line having only one dimension (e.g., a single column). Alternatively, the array 180 may be irregular and / or form a grid corresponding to a mark. The array 180 shown in the figures is one non-limiting arrangement of the array 180.

[0071] Control of the electro-optical segments 179 may affect control of adjacent electro-optical segments 179. For example, when the voltage associated with the first segment 186 is adjusted, the voltage supplied to the surrounding segments (e.g., the second segment 188) may be changed as well. Thus, an oscillatory feedback loop may be achieved, since the controller 73 may be operable to sample a discrete-time feedback signal associated with the voltage of the electro-optical segments 186, 188. In other words, control of the drive transistors 174, 176 may cause a change in the voltage of the adjacent electro-optical segments 179 due to their common connection with the first and second electrodes 22, 26, and the controller 73 may utilize this response to maximize uniformity.

[0072] As previously described with respect to the single switching layer 56, the switching layers 170, 172 may include multiple electrode traces 160, 162, 164 and may define cavities 142 associated with each switching circuit 76, 78, as shown in FIG. 11. Thus, each switching layer 170, 172 may include a first set of electrode traces 194 and a first cavity 196 corresponding to the first electro-optical segment 186. Each switching layer 170, 172 may also define a second set of electrode traces 198 and a second cavity 200 corresponding to the second electro-optical segment 188. It is generally contemplated that each set of electrode traces may include additional electrode traces to allow for control and / or monitoring of the dual active plate or temperature monitoring. The first switching circuit 76 and the third switching circuit 190 may be disposed within the first cavity 196 and the second cavity 200, respectively, of the first switching layer 170. The second switching circuit 78 and the fourth switching circuit 192 may be disposed within a first cavity 196 and a second cavity 200, respectively, of the second switching layer 172.

[0073] 12 and 13, a configuration of an electro-optical device 10 having first and second electro-optical segments 186, 188 is illustrated. It is generally contemplated that any number of electro-optical segments 179 may be arranged in parallel with the electro-optical segments 186, 188, as indicated by the continuation of the nodes passing through the first electrode 22 and the second electro-optical segment 188. With reference to FIG. 12, the electro-optical device 10 is shown with a single active plate, while FIG. 13 illustrates an electro-optical device 10 having two active plates. As shown in the figures, a third control circuit 70c may be provided to control a third switching circuit 190. As shown in FIG. 13, a fourth control circuit 70d may be provided to control a fourth switching circuit 192. It is generally contemplated that each control circuit 70a, 70b, 70c, 70d may be controlled by a single IC 116 via a selection node for each control circuit. 12 and 13 illustrate the scalability of the electro-optical segment 179 within the electro-optical device 10. In general, it is contemplated that hybrid electro-optical devices 10 having dual-part and single-part active plate configurations may be constructed in accordance with aspects of the present disclosure. In other words, in some configurations, the electro-optical device 10 includes two active plates associated with a first electro-optical segment 186 and one active plate associated with a second electro-optical segment 186.

[0074] In operation, IC 116 may be used to adjust the current to each segment, and then a control loop may monitor the voltage and control drive transistors 174, 176 to the desired set point. In this manner, second DAC 102 may drive each electro-optical segment 179 continuously and directly. In a 0.5m x 1.0m window assembly (e.g., a sunroof window), up to 1,000 electro-optical segments may be provided, each with a footprint of 1 square millimeter. Thus, the resistance of the ITO backplane may significantly affect the voltage / current of each segment across the length L or width W of the electro-optical device 10. Thus, controller 73 may be configured to incorporate feedback / control of voltage and current to safely and uniformly control multiple electro-optical segments 179.

[0075] 14, one configuration of the electro-optical element 42 includes at least one op-amp 202, 204 operable to control one or more of the drive transistors 120. For example, each switching circuit (e.g., second and fourth switching circuits 78, 192) may include a first op-amp (op-amp 202) in electrical communication with a second op-amp 204 downstream of the first op-amp 202. Each op-amp 202, 204 may include an inverting input terminal 206, a non-inverting input terminal 208, and an output terminal 210 that controls an output signal based on a voltage difference between the inverting input terminal 206 and the non-inverting input terminal 208. Additionally, each op-amp 202, 204 may include two power inputs 212 to allow each op-amp 202, 204 to amplify a signal provided to the op-amp. The first op-amp 202 may be operable to receive a voltage difference between the first electrode 22 and the intermediate electrode 30. The second op-amp 204 may be operable to receive a voltage difference between the voltage of the first output 214 of the first op-amp 202 and a control signal node 215. The control signal node 215 may correspond to the first drive node 108 of the previous embodiment. A second output 216 of the second op-amp 204 may be in electrical communication with the third leg 126 of the drive transistor 120.

[0076] In operation, the voltage at the control signal node 215 may effectively control the voltage across the electro-optical segments 186, 188. For example, the power supply circuit 24 may provide a high global voltage V G (e.g., 6V). G The polarity of the Vth may be reversed to allow for faster clearing of the electro-optical device 10. Alternatively, a four-transistor H-bridge 218 may be used to drive each individual electro-optical segment 186, 188 with either polarity (FIG. 15). For example, as shown, one H-bridge 218 may be associated with each of a pair of electro-optical segments 186, 188 and / or one H-bridge 218 may be connected to the global voltage Vth. G 2. The four-transistor H-bridge 218 may be used to control the polarity of the power supply voltage Vcc of the H-bridge 218. It is contemplated that the controller 73 may be configured to activate an individually controlled transistor (e.g., first transistor 220, 222) of the H-bridge 218 to provide a non-inverted power signal to the electro-optical device 10 (e.g., individual electro-optical segments 179) when the second transistor 224, 226 of the H-bridge 218 is deactivated. Similarly, the controller 73 may be configured to activate a second transistor 224, 226 of the H-bridge 218 to provide an inverted power signal to the electro-optical device 10 when the first transistor 220, 222 is deactivated. A voltage protection circuit 228, such as the illustrated parallel diode circuit, may be incorporated into each of the transistors 220, 222, 224, 226 to prevent electrical shorting of the H-bridge 218 and / or the power supply. It is contemplated that the four-transistor H-bridge 218 may be incorporated into any of the configurations discussed above.

[0077] One electrode of each electro-optical segment 186, 188 may be connected to the first node 74 of the power supply circuit 24. The voltage at the control signal node 215 is a global voltage V across the electro-optical segments 186, 188. GThe second op-amp 204 may then output a signal based on the difference between the target voltage at the control signal node 215 and the output voltage of the first op-amp 202. The output voltage of the first op-amp 202 may be proportional to the voltage across the electro-optical segments 186, 188, such that the global voltage V G The control of the control signal node 215 may result in self-regulation (e.g., pre-configured voltage adjustment of the electro-optical segment 179). In other words, according to some embodiments, the controller 73 may not require direct feedback to achieve proper voltage control of the electro-optical element 42. In some configurations, the controller 73 may be omitted and the reference voltage provided by the control signal node 215 may be provided directly by the power supply circuit 24.

[0078] The electro-optical element 42 and the first and second substrates 38, 40 may be formed of a variety of materials. For example, the first and second substrates 38, 40 may include plastic materials. Plastics for the first and second substrates 38, 40 may include, but are not limited to, polycarbonate, polyethylene terephthalate (PET), polyester, polyimide, polyamide, acrylic, cyclic olefin, polyethylene (PE), metallocene polyethylene (mPE), polyethylene naphthalate (PEN), silicone, urethane, and various polymeric materials. The first and second substrates 38, 40 may be glass in various forms, including, but are not limited to, soda-lime float glass, borosilicate glass, boroaluminosilicate glass, or various other compositions. When using glass substrates, the first and second substrates 38, 40 may be annealed, thermally strengthened, chemically strengthened, partially strengthened, or fully strengthened. The electro-optical element 42 forming the panel (e.g., window, display, selective display, etc.) may be supported by a frame. The frame may correspond to a partial or complete frame that may be used to support a window panel as required.

[0079] The first and second substrates 38, 40 and the one or more protective layers may be adhered together by one or more laminate materials. For example, the laminate material may correspond to at least one of the following materials: polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), thermoset EVA ethylene vinyl acetate (EVA), and thermoplastic polyurethane (TPU). Specific materials are described in this disclosure and may correspond to exemplary materials that may be used as laminate materials to adhere to one or more of the first and second substrates 38, 40 and / or additional protective layers or coatings.

[0080] According to various aspects, the electro-optical element 42 may include a memory chemistry configured to retain a state of transmittance when the vehicle and window control module are inactive (e.g., not actively receiving energy from the vehicle's power source). That is, the electro-optical element 42 may be implemented as an electrochromic device having a persistent color memory configured to provide current during clearing for a substantial period of time after charging. Examples of such devices are described in U.S. Patent No. 9,964,828, entitled "ELECTROCHEMICAL ENERGY STORAGE DEVICES," the disclosure of which is incorporated herein by reference in its entirety.

[0081] The electro-optical element may correspond to an electrochromic device as described herein configured to change the transmittance of a window in response to an applied voltage through the window. Examples of control circuits and related equipment that may be configured to provide electrodes and hardware configured to control electro-optical elements are generally described in commonly assigned U.S. Pat. No. 8,547,624, entitled "VARIABLE TRANSMISSION WINDOW SYSTEM," U.S. Pat. No. 6,407,847, entitled "ELECTROCHROMIC MEDIUM HAVING A COLOR STABILITY," U.S. Pat. No. 6,239,898, entitled "ELECTROCHROMIC STRUCTURES," U.S. Pat. No. 6,597,489, entitled "ELECTRODE DESIGN FOR ELECTROCHROMIC DEVICES," and U.S. Pat. No. 5,805,330, entitled "ELECTRO-OPTIC WINDOW INCORPORATING A DISCRETE PHOTOVOLTAIC DEVICE," the entire disclosures of each of which are incorporated herein by reference.

[0082] Examples of electrochromic devices that may be used in windows are described in U.S. Pat. No. 6,433,914, entitled "COLOR-STABILIZED ELECTROCHROMIC DEVICES," U.S. Pat. No. 6,137,620, entitled "ELECTROCHROMIC MEDIA WITH CONCENTRATION-ENHANCED STABILITY, PROCESS FOR THE PREPARATION THEREOF AND USE IN ELECTROCHROMIC DEVICES," U.S. Pat. No. 5,940,201, entitled "ELECTROCHROMIC MIRROR WITH TWO THIN GLASS ELEMENTS AND A GELLED ELECTROCHROMIC MEDIUM," and U.S. Pat. No. 7,372,611, entitled "VEHICULAR REARVIEW MIRROR ELEMENTS AND ASSEMBLIES INCORPORATING THESE ELEMENTS," the entire disclosures of each of which are incorporated herein by reference. Other examples of variable transmission windows and systems for controlling them are disclosed in commonly assigned U.S. Patent No. 7,085,609, entitled "VARIABLE TRANSMISSION WINDOW CONSTRUCTIONS," and U.S. Patent No. 6,567,708, entitled "SYSTEM TO INTERCONNECT, LINK, AND CONTROL VARIABLE TRANSMISSION WINDOWS AND VARIABLE TRANSMISSION WINDOW CONSTRUCTIONS," each of which is incorporated herein by reference in its entirety. In other embodiments, the electro-optical device may include suspended particle devices, liquid crystals, or other systems that change transmittance through the application of an electrical property.

[0083] According to one aspect of the disclosure, an electro-optical device includes a first electrode in electrical communication with a power supply circuit. A second electrode is spaced apart from the first electrode and in electrical communication with the power supply circuit. An electro-optic medium is disposed between the first and second electrodes. At least one third electrode is disposed between the first and second electrodes and in electrical communication with one of the first and second electrodes via a switching circuit. The switching circuit is operable to control a current through the first electrode, the electro-optic medium, and the second electrode.

[0084] According to one aspect of the present disclosure, the device further comprises a control circuit in communication with the switching circuit and configured to control the switching circuit to regulate current through the first electrode, the electro-optic medium, and the second electrode.

[0085] According to one aspect of the present disclosure, the control circuitry is in communication with the at least one third electrode and one of the first and second electrodes to determine a voltage drop across the electro-optic medium.

[0086] According to one aspect of the disclosure, the control circuit is operable to control the switching circuit based on the voltage drop across the electro-optic medium.

[0087] According to one aspect of the disclosure, the control circuit is operable to control the power supply circuit based on the voltage drop across the electro-optic medium.

[0088] According to one embodiment of the present disclosure, the switching circuit includes a first switching circuit and a second switching circuit, and the at least one third electrode includes a first intermediate electrode corresponding to the first switching circuit and a second intermediate electrode corresponding to the second switching circuit.

[0089] According to one aspect of the present disclosure, the first switching circuit is disposed in a first switching layer interposed between the first electrode and the first intermediate electrode, and the second switching circuit is disposed in a second switching layer interposed between the second electrode and the second intermediate electrode.

[0090] According to one aspect of the disclosure, one of the first switching layer and the second switching layer includes a first transistor operable to prevent current from flowing through the electro-optic medium.

[0091] According to one embodiment of the present disclosure, the first transistor is a thin film transistor.

[0092] According to one aspect of the present disclosure, the at least one third electrode includes a third intermediate electrode parallel to the first intermediate electrode, and the first switching circuit includes a second transistor operable to inhibit the current from flowing through the electro-optic medium.

[0093] According to one aspect of the disclosure, the control circuitry is in communication with the first intermediate electrode and the second intermediate electrode to determine a voltage drop across the electro-optic medium.

[0094] According to one aspect of the disclosure, an electro-optical device includes a first electrode electrically connected to a power supply circuit. A second electrode is spaced apart from the first electrode and electrically connected to the power supply circuit. An electro-optical medium is disposed between the first and second electrodes. At least one third electrode is disposed between the first and second electrodes and electrically connected to one of the first and second electrodes via a switching circuit. A control circuit is in communication with and controls the switching circuit to control current through the first electrode, the electro-optical medium, and the second electrode.

[0095] It will be understood that any described process or step within a described process may be combined with other processes or steps disclosed to form structures within the scope of the present apparatus. The exemplary structures and processes disclosed herein are for illustrative purposes and are not to be construed as limiting.

[0096] It is also to be understood that variations and modifications may be made in the structure and methods described above without departing from the concepts of the present apparatus, and that such concepts are intended to be covered by the following claims unless expressly stated otherwise in language in those claims.

[0097] The above description is to be considered as only a description of the illustrated embodiment. Modifications of the device will occur to those skilled in the art and to those who make or use the device. Therefore, it will be understood that the embodiments shown in the drawings and the above description are merely for illustrative purposes and are not intended to limit the scope of the device, which is defined by the following claims, which are to be interpreted in accordance with the principles of patent law, including the doctrine of equivalents.

Claims

1. An electro-optical device, A first electrode electrically connected to a power supply circuit; a second electrode spaced apart from the first electrode and electrically connected to the power supply circuit; an electro-optic medium disposed between the first electrode and the second electrode; at least one third electrode disposed between the first electrode and the second electrode; a control circuit electrically connected to one of the first electrode and the second electrode; Equipped with The control circuit includes: monitoring the measured control signal of the third electrode; Adjusting a drive control signal delivered to the one of the first electrode and the second electrode based on the measured control signal to update a corresponding transmission state of the electro-optical device to a target transmittance. Electro-optical device.

2. The control circuitry further compares the measured control signal to correspond to the target transmittance of the electro-optical device for the drive control signal and adjusts the drive control signal based on the comparison.

2. The electro-optical device according to claim 1.

3. the measured control signal is indicative of a potential between the first electrode and the second electrode; The drive control signal adjusts the potential between the first electrode and the second electrode to adjust the electro-optical element to the target transmittance.

3. The electro-optical device according to claim 2.

4. the at least one third electrode is interposed between the electro-optic medium and one of the first and second electrodes and extends across at least a portion of a transmissive surface area through which light is selectively transmitted in response to the electrical signal.

4. The electro-optical device according to claim 1, wherein the first and second electrodes are arranged in a first direction.

5. The control circuit includes a switching circuit that electrically connects the at least one third electrode to the one of the first electrode and the second electrode.

5. The electro-optical device according to claim 1,

6. The switching circuit controls a current conducted through the first electrode, the electro-optic medium, and the second electrode, resulting from the drive control signal.

6. The electro-optical device according to claim 5.

7. The monitoring of the control signal includes monitoring a voltage drop from the first electrode to the second electrode across the electro-optic medium.

6. The electro-optical device according to claim 5.

8. The control circuit further controls the switching circuit based on the voltage drop across the electro-optic medium.

8. The electro-optical device according to claim 7.

9. The control circuit controls the drive control signal by controlling the power supply circuit based on the voltage drop across the electro-optic medium.

8. The electro-optical device according to claim 7.

10. the switching circuit includes a first switching circuit and a second switching circuit; The at least one third electrode includes a first intermediate electrode conductively connected to the first switching circuit and a second intermediate electrode conductively connected to the second switching circuit.

6. The electro-optical device according to claim 5.

11. the first intermediate electrode is interposed between the first electrode and the electro-optic medium; The second intermediate electrode is interposed between the second electrode and the electro-optic medium.

11. The electro-optical device according to claim 10.

12. the first switching circuit is disposed in a first switching layer interposed between the first electrode and the first intermediate electrode; The second switching circuit is disposed in a second switching layer interposed between the second electrode and the second intermediate electrode.

12. The electro-optical device according to claim 11.

13. One of the first switching layer and the second switching layer includes a first transistor operable to prevent the current from flowing through the electro-optic medium.

13. The electro-optical device according to claim 12.

14. the at least one third electrode includes a third intermediate electrode parallel to the first intermediate electrode; The first switching circuit includes a second transistor operable to inhibit the current from flowing through the electro-optic medium.

14. The electro-optical device according to claim 13.

15. The control circuit is in communication with the first intermediate electrode and the second intermediate electrode and identifies the measured control signal as a voltage drop across the electro-optic medium between the first intermediate electrode and the second intermediate electrode.

15. The electro-optical device according to claim 10,

16. 1. A method for controlling an electro-optical device, comprising: providing a drive control signal to at least one of a first electrode and a second electrode of the electro-optical device; inducing a current across an electro-optic medium between the first electrode and the second electrode; monitoring a measured control signal of at least one third electrode conductively connected to one of the first and second electrodes; adjusting the drive control signals based on the measured control signals, thereby updating a corresponding transmission state of the electro-optical device to a target transmission; A method comprising:

17. the monitoring step includes comparing the measured control signal to correspond to the target transmittance of the drive control signal; The adjusting step includes updating the drive control signal based on the comparison.

17. The method of claim 16.

18. adjusting the transmissive state to the target transmittance by controlling a switching circuit that electrically connects the at least one third electrode to the one of the first electrode and the second electrode.

18. The method of claim 16 or 17, further comprising:

19. The switching circuit controls the current conducted through the electro-optic medium from the one of the first electrode and the second electrode resulting from the drive control signal.

20. The electro-optical device according to claim 18.

20. An electro-optical device, A first electrode electrically connected to a power supply circuit; a second electrode spaced apart from the first electrode and electrically connected to the power supply circuit; an electro-optic medium disposed between the first electrode and the second electrode; at least one third electrode disposed between the first electrode and the second electrode and electrically connected to one of the first electrode and the second electrode via a switching circuit; a control circuit in communication with the switching circuit and configured to control the switching circuit to regulate current through the first electrode, the electro-optic medium, and the second electrode; 1. An electro-optic medium comprising:

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