Glazing unit with light modulator and temperature regulating layer

Abstract

Some embodiments are directed to a glazing unit. The glazing unit includes a light modulator, and a liquid-filled, temperature regulating layer, the temperature regulating layer being arranged against the light modulator, outside of the optical layer, and extending across the surface of the first or second substrate, the temperature regulating layer being arranged for cooling and / or heating of the light modulator.

Description

TECHNICAL FIELD

[0001] The presently disclosed subject matter relates to a glazing unit.BACKGROUND

[0002] A known glazing unit is described in the article "Vacuum glazing: Current performance and future prospects," by Philip C. Eames. The known glazing unit comprises an insulating layer, in this case a low-pressure layer. The article explains that vacuum glazing is similar to double glazing in which the gas-filled space is evacuated to low pressure, thus reducing the levels of convection and gaseous conduction to negligible values.

[0003] The known vacuum glazing is assembled from two glass sheets, cut to the required dimensions. In one of the sheets an evacuation tube is installed, which is attached during manufacture to an evacuation system. After evacuation, the evacuation tube is sealed.

[0004] The known glazing units have several shortcomings. In particular, when used in a building facade, the known glazing cannot adjust for incoming solar radiation.SUMMARY

[0005] It would be advantageous to have an improved glazing unit. A glazing unit is described that comprises a light modulator, and a liquid-filled, temperature regulating layer.

[0006] The light modulator may comprise a first substrate and a second substrate, the first and second substrates being arranged with inner sides opposite to each other, one or more driving electrodes being applied to the inner side of the first substrate, and an optical layer between the first and second substrates, the one or more driving electrodes being configured to cause modulation of optical properties of the optical layer.

[0007] The temperature regulating layer may be arranged against the light modulator, outside of the optical layer, and extending across a surface of the light modulator. The temperature regulating layer may be arranged for cooling and / or for heating of the light modulator.

[0008] In an embodiment, the glazing unit comprises an insulating layer. The insulating layer is preferably a low-pressure layer.BRIEF DESCRIPTION OF DRAWINGS

[0009] Further details, aspects, and embodiments will be described, by way of example only, with reference to the drawings. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. In the figures, elements which correspond to elements already described may have the same reference numerals. In the drawings, Figure 1a schematically shows an example of an embodiment of light modulator with temperature regulating layer, Figure 1b schematically shows an example of an embodiment of light modulator with temperature regulating layer, Figure 1c schematically shows an example of an embodiment of light modulator with temperature regulating layer, Figure 1d schematically shows an example of an embodiment of light modulator with temperature regulating layer, Figure 1e schematically shows an example of an embodiment of light modulator with temperature regulating layer, Figure 2a schematically shows an example of an embodiment of a glazing unit, Figure 2b schematically shows an example of an embodiment of a glazing unit, Figure 3 schematically shows an example of an embodiment of a glazing unit, Figure 4 schematically shows an example of an embodiment of a glazing unit, Figure 5 schematically shows an example of an embodiment of method of manufacturing a light modulator system and / or a glazing unit. Figure 6a schematically shows an example of an embodiment of a building block, Figure 6b schematically shows an example of an embodiment of a substrate, Figures 7a-7f schematically show an example of an embodiment of a substrate, Figure 8a schematically shows an example of an embodiment of a light modulator, Figure 8b schematically shows an example of an embodiment of a light modulator, Figure 8c schematically shows an example of an embodiment of a car, Figures 9a-9c schematically show an embodiment of a light modulator, Figure 10 schematically shows an example of an embodiment of a method for making vacuum insulated glass, Reference signs list

[0010] The following list of references and abbreviations corresponds to the figures, and is provided for facilitating the interpretation of the drawings and shall not be construed as limiting the claims. 100-104a light modulator with liquid cooling 110a light modulator 111a first substrate 112a second substrate 113one or more driving electrodes 114an optical layer 121a first glazing substrate 122a second glazing substrate 130temperature regulating layer 131a first substrate 132a second substrate 140an insulating layer, e.g., a low pressure layer 151an optical layer spacer 152an insulating layer spacer, e.g., a low pressure layer spacer 153a temperature regulating layer spacer 160a controller 161a temperature sensor 162an outside sensor 163an inside sensor 170a thermoelectric element 171a heat sink 172liquid exchange mechanism 173a frame 191an outside side 192an inside side 200-201a glazing unit 300a glazing unit 400a glazing unit 401a sunshade 410a pivot 600a substrate 611-614a main line 621-624a main line 631-634interdigitated electrodes 640a building block 641-644a building block 610, 620a driving bus 619, 629a connecting zone 691, 692a direction 10a light modulator 11a first substrate 12a second substrate 13, 13a, 13belectrodes 14, 14a, 14belectrodes 15a fluid 16a controller 18a spacer 30particles 20a car 21a light modulator 40a light modulator 41a first substrate 42a second substrate 43a third substrate 46a controller DESCRIPTION OF EMBODIMENTS

[0011] While the presently disclosed subject matter is susceptible of embodiment in many different forms, there are shown in the drawings and will herein be described in detail one or more specific embodiments, with the understanding that the present disclosure is to be considered as exemplary of the principles of the presently disclosed subject matter and not intended to limit it to the specific embodiments shown and described.

[0012] In the following, for the sake of understanding, elements of embodiments are described in operation. However, it will be apparent that the respective elements are arranged to perform the functions being described as performed by them.

[0013] Further, the subject matter that is presently disclosed is not limited to the embodiments only, but also includes every other combination of features described herein or recited in mutually different dependent claims.

[0014] Figure 1a schematically shows an example of an embodiment of a light modulator system 100 comprising a temperature regulating layer 130 and a light modulator 110.

[0015] The light modulator is suitable for integration into a glazing unit, e.g., by combining the light modulator with a temperature insulating layer. Such integration is advantageous but not necessary. For example, the temperature insulating layer may be a low-pressure layer. For example, the temperature insulating layer may be another type of insulating layer, e.g., as used in double glazing, such as a gas-filled layer, e.g., filled with argon and / or krypton, which provides improved thermal insulation by reducing heat transfer. The temperature insulating layer has lower thermal conductivity compared to air, thereby enhancing the overall energy efficiency of the glazing unit.

[0016] Light modulator system 100 may be any light modulator, e.g., as described herein. In particular, the light modulator system 100 comprises an optical layer. The optical properties of the optical layer may be modulated electrically, e.g., by one or more driving electrodes arranged in or near the optical layer. For example, the driving electrodes may be arranged to modulate an electric field inside the optical layer, causing modulation of the optical properties. Light passing through the light modulator will be affected by the optical layer and its optical properties as configured electrically, e.g., through the one or more driving electrodes.

[0017] Typically, the optical state of the light modulator can be varied between more transparent and less transparent states. Often, grayscale control between these two states is possible. There are various other optical properties for which the light modulator could be configured, e.g., more or less reflective states.

[0018] In an embodiment, the light modulator has multiple segments that are independently and electrically controllable, meaning they have independently and electrically controllable optical properties. For example, one segment may have different transparency or reflectivity compared to another segment.

[0019] A liquid-filled temperature regulating layer is arranged next to the light modulator. The temperature regulating layer is positioned against the light modulator outside of the optical layer and extends across a surface of light modulator 110.

[0020] Both the optical layer and the temperature regulating layer are each arranged between two substrates, one of which may be shared between the two layers. The substrates are typically transparent.

[0021] The temperature regulating layer may be arranged for cooling the light modulator. Heat may build up in the light modulator, e.g., due to transitions between different optical states of the light modulator or from sunlight impinging on the light modulator. Especially if the light modulator is in a less transparent state, e.g., a more opaque state, the energy from sunlight may increase heat inside the light modulator. Excessive heat, especially if prolonged, can have detrimental effects, e.g., reduced lifespan of the optical modulator. For example, the temperature regulating layer may be configured to transfer heat away from the light modulator.

[0022] Furthermore, the temperature regulating layer may be used to increase the temperature of the light modulator. Typically, a light modulator does not function well if its temperature is too low. The temperature regulating layer may be configured to transfer heat to the light modulator, in particular its optical layer, for improved functioning. For example, a light modulator placed in a region with low ambient temperatures is beneficially heated to improve functioning.

[0023] In a further advantageous embodiment, the temperature regulating layer selectively lowers and / or increases the temperature. Transitions in the optical layer, e.g., for a particle-based optical layer, proceed faster at a higher temperature. Especially diffusion of particles, e.g., as needed for decreasing transparency, proceeds faster at higher temperatures. Accordingly, the temperature regulating layer may be configured to increase the temperature in the optical layer, e.g., by transferring heat towards it or by cooling it less before and / or during an optical state transition, in particular a transition to a less transparent state.

[0024] Preferably, the refractive index of the temperature regulating layer is tuned to the refractive index of the light modulator, e.g., of the substrates enclosing the light modulator. For example, the temperature regulating layer may have a refractive index within ±0.03 of the refractive index of the light modulator, e.g., its substrates, preferably within ±0.02, more preferably ±0.01.

[0025] The temperature regulating layer is filled with a liquid, preferably a liquid with high thermal conductivity. For example, the liquid may have a thermal conductivity of at least 0.1 W / (m K) at 25°C, preferably at least 0.2 W / (m K) at 25°C. For example, the liquid may comprise a glycol-based compound.

[0026] Reference is made to European patent applications EP24177302.7 and EP24194098.0, which describe vacuum-insulated glass and methods for making vacuum-insulated glass. The vacuum-insulated glass method can be used to prepare a heat-regulating window by replacing the vacuum between the substrates with a high heat conductive liquid.

[0027] There are several ways to use a temperature regulating layer. In a first example, the temperature regulating layer is passive. Heat from the light modulator is absorbed in the temperature regulating layer, where it diffuses. When the light modulator is in a state that does not produce heat, the light modulator and temperature regulating layer will both dissipate heat to the environment. In this way, heat regulation takes place while no external communication between the temperature regulating layer and the environment is needed. Additionally, the temperature regulating layer diffuses local heat generated on the window. For example, when the sun is shining partially on a window, surface temperature difference of the glass may create cracks and defects due to strong temperature change in short distances. By reducing temperature difference across the glazing unit, the temperature regulating layer may limit or even eliminate such effects.

[0028] A second example is shown in Figure 1b. Figure 1b schematically shows an example of an embodiment of light modulator system 101 comprising a temperature regulating layer 130 and a light modulator 110.

[0029] In a second example, the temperature regulating layer is also sealed without liquid exchange. However, the temperature regulating layer is in contact with a heat sink 171. For example, the heat sink 171 may be in contact around the perimeter of the light modulator and temperature regulating layer. The heat sink 171 may also contact the perimeter of the light modulator. For example, the heat sink 171 may be integrated into a frame, e.g., a frame of a glazing unit.

[0030] Heat from the light modulator is absorbed in the temperature regulating layer, where it diffuses. The temperature regulating layer is connected to the heat sink, which will also absorb the heat. The heat sink may further release heat to the environment.

[0031] The heat sink is typically used to extract heat from the system but could also be used to heat the temperature regulating layer if needed; for example, to increase temperature before or during optical transitions.

[0032] Heat sink 171 is a passive component that dissipates heat in the temperature regulating layer, e.g., generated by the light modulator or absorbed from the sun into the surrounding environment. The heat sink comprises a material with high thermal conductivity, such as metal, e.g., aluminum or copper, to transfer heat away from the device.

[0033] The heat sink may have surface elements that increase the surface area for heat dissipation through convection, e.g., fins and / or ridges.

[0034] The heat sink may be combined with active cooling to enhance cooling efficiency, e.g., air-cooling, e.g., fans; liquid-cooling. For example, the active cooling may cool the heat sink and / or surface elements. Alternatively, active heating may heat the heat sink and / or surface elements. Active heating may use instead or in addition, an integrated heating element, e.g., heating electrodes arranged on a surface of a substrate of the light modulator system, in particular on a surface facing the temperature regulating layer, and / or a surface facing the optical layer.

[0035] In a third example, the temperature regulating layer exchanges liquid with the environment. Figure 1c schematically shows an example of an embodiment of light modulator system 102 comprising a temperature regulating layer 130 and a light modulator 110. The temperature regulating layer is connected to a liquid exchange mechanism 172. In this embodiment, the temperature regulating layer is not only responsible for absorbing and diffusing heat from the light modulator but also actively engages in heat exchange with the environment through a liquid exchange mechanism 172.

[0036] The temperature regulating layer is connected to a liquid exchange mechanism 172, which allows for the flow of liquid into and out of the temperature regulating layer. This setup allows quick, precise, and dynamic regulation of the temperature within the layer by directly exchanging heated liquid with cooler liquid from the environment or vice versa, depending on the thermal requirements of the system.

[0037] For example, liquid exchange mechanism 172 may comprise a valve, e.g., multiple valves. The valve can control the circulation of liquid. For example, a first valve may allow liquid to flow into the temperature regulating layer, while a second valve may control liquid flowing out of the temperature regulating layer. There may be multiple first valves and multiple second valves. The valves are convenient but optional. For example, the valves make connecting and disconnecting to a pump more convenient.

[0038] A pump may be operatively connected to the temperature regulating layer through liquid exchange mechanism 172, e.g., connecting to said valves. The pump is configured to circulate the liquid within the temperature regulating layer, enhancing the heat transfer process. By actively circulating the liquid, the system can more effectively dissipate heat from the light modulator. For example, when the liquid is outside of the temperature regulating layer, it can be actively heated or cooled as desired. This allows for quick and precise modulation of the temperature in the temperature regulating layer and, from there, in the light modulator.

[0039] The temperature regulating layer may form a chamber for the liquid from which liquid exchange is done through mechanism 172. In an embodiment, the temperature regulating layer includes channels or microchannels through which the liquid flows. These channels facilitate efficient heat transfer by maximizing the surface area contact between the liquid and the material of the temperature regulating layer.

[0040] One application of the temperature regulating layer is to cool the light modulator. Another application of the temperature regulating layer is to heat the light modulator, especially before or during optical transitions, most especially for a transition to a more opaque state, e.g., wherein particles in the optical layer disperse. Accordingly, the temperature regulating layer may be configured to heat the light modulator. After the transition is complete, the temperature regulating layer may cool the light modulator. This helps maintain the stability of the light modulator, e.g., the time during which the light modulator's optical state is stable without actively electrically controlling the light modulator.

[0041] For example, a controller may be operatively connected to the temperature regulating layer. The controller is configured to monitor the temperature of the light modulator and adjust the temperature of the liquid in the temperature regulating layer. The temperature of the light modulator may be measured directly, e.g., through a sensor integrated with the light modulator. The light modulator temperature may also be obtained from a virtual sensor, e.g., a temperature estimate obtained from a model that takes as input various other measurements, e.g., that may be easier to obtain, e.g., one or more of: ambient temperature outside, ambient temperature inside, solar irradiance, solar hours, previous use of the light modulator, etc. For example, the model could be a neural network; even a small neural network will work.

[0042] The liquid in the temperature regulating layer may be heated by environmental conditions, external sources of heat, and / or directly by an heating system integrated in the glazing unit, e.g., on a substrate, such as a substrate of the temperature regulating layer. For example, integrated heating may be done by current passing through electrodes on a surface of the substrate; for example, the heating electrodes may be arranged across a surface of the temperature regulating layer. Heating may also be performed by passing a current through driving electrodes of the light modulator. In the latter case the temperature regulating layer help diffusing the additional heat.

[0043] The controller is configured to maintain the light modulator temperature within a predetermined temperature range by selectively heating or cooling the liquid in the temperature regulating layer. For example, one of the embodiments of Figures 1b and 1c may be used for active temperature control of the temperature regulating layer. The predetermined temperature may depend on the intended use of the light modulator. For example, if the light modulator is about to or is undergoing an optical state transition, a higher temperature may be maintained than when the light modulator is stable.

[0044] In an embodiment, the light modulator comprises an anti-reflective coating, e.g., applied to the temperature regulating layer.

[0045] Figure 1d schematically shows an example of an embodiment of light modulator system 103 comprising a temperature regulating layer 130 and a light modulator 110.

[0046] Light modulator 110 comprises a first substrate 111 and a second substrate 112. The first and second substrates are arranged with their inner sides opposite to each other. An optical layer 114 is arranged between the first and second substrates. In this example, light modulator optical layer 114 comprises a fluid, e.g., a liquid that comprises particles.

[0047] One or more driving electrodes 113 are applied on the inner side of first substrate 111 and the inner side of second substrate 112. The light modulator is configured to apply an electric potential to the one or more driving electrodes, causing modulation of an electric field in the optical layer. This, in turn, causes electrophoretic and / or dielectrophoretic movement of the particles in the optical layer, leading to modulation of light passing through the substrates.

[0048] In the example shown two electrodes applied on substrate 111: electrodes 113.1 and 113.2 The two electrodes may each contain multiple electrode lines, e.g., main lines, or fingers, and alternate on the substrate. In the example shown two electrodes applied on substrate 112: electrodes 113.3 and 113.4 The two electrodes may each contain multiple electrode lines, e.g., main lines, or fingers, and alternate on the substrate. A four electrode design, with at least two electrodes per substrate is advantageous, but designs with various numbers of electrodes are possible.

[0049] Next to light modulator 110, a temperature regulating layer 130 is arranged. Temperature regulating layer 130 is enclosed between two substrates. Shown are first substrate 131 and second substrate 132, between which extends temperature regulating layer 130. As shown, first substrate 131 is adjacent to second substrate 112.

[0050] Using two substrates for temperature regulating layer 130 is convenient as it allows for the manufacture of the temperature regulating layer separately from the light modulator.

[0051] Also shown in light modulator system 103 are optical layer spacers 151. Depending on the area and thickness of the optical layer 114 and the thickness of substrates 111 and 112, optical layer spacers 151 may be included in the design to keep the light modulator flat. Although not shown in Figure 1d, spacers may also be included in the temperature regulating layer.

[0052] For example, spacers may be applied onto substrates 131, 132, 112, and / or 111 by various processes, e.g., using photolithography, before assembling the light modulator system. Spacers may be included in each of the layers shown herein.

[0053] In an embodiment, multiple spacers are arranged in the optical layer as well as in the temperature regulating layer. In an embodiment, at least part of the multiple spacers arranged in the optical layer may be aligned with at least part of the multiple spacers arranged in the temperature regulating layer. This arrangement increases the mechanical integrity of the light modulator system. In fact, all of the optical layer spacers may align with a temperature layer spacer, although this is not necessary.

[0054] The light modulator system may be further mechanically protected by an insulating layer, such as a low-pressure layer, and glazing substrates.

[0055] The light modulator system temperature may be homogenized and / or kept at a desired level by heating or cooling the temperature regulating layer.

[0056] A thermoelectric material may be included between first substrate 111 and second substrate 112 in the optical layer. The thermoelectric material is configured to generate electricity from heat.

[0057] Figure 1e schematically shows an example of an embodiment of light modulator system 104 with a temperature regulating layer.

[0058] Light modulator system 104 comprises a light modulator 110. Light modulator 110 comprises an optical layer 114 enclosed between a first substrate 111 and a second substrate 112. Light modulator system 104 comprises a temperature regulating layer 130 enclosed between two substrates. The two substrates of the temperature regulating layer have a substrate in common with the light modulator.

[0059] In this case, the optical layer is enclosed between substrates 111 and 112. The temperature regulating layer 130 is enclosed between substrates 112 and 132. Thus, one less substrate can be used. This reduces costs and increases the effectiveness of the temperature regulating layer 130. This arrangement can be manufactured, for example, by stacking the substrates as could be done in an LCD machine.

[0060] Shown in Figure 1e is a temperature sensor 161 integrated into the temperature regulating layer. Alternatively, or in addition, temperature sensor 161 may be integrated into the optical layer itself. Communication with sensor 161 may be through electrode lines on the substrate on which the sensor is applied, in this example, on substrate 112.

[0061] Having only one substrate between the temperature regulating layer increases the accuracy of sensor 161. Sensor 161 may be integrated into the other light modulator systems shown herein and in glazing units as well.

[0062] Figure 2a schematically shows an example of an embodiment of a glazing unit 200.

[0063] Glazing unit 200 comprises a light modulator system, including a light modulator 110 and a temperature regulating layer 130. For example, the light modulator system may be as shown with respect to Figures 1a-1e. Glazing unit 200 comprises an insulating layer 140, preferably a low-pressure layer.

[0064] In the example shown, temperature regulating layer 130 is arranged between light modulator 110 and insulating layer 140. Insulating layer 140 is arranged on a side of light modulator 110 adjacent to temperature regulating layer 130, wherein the low-pressure layer extends across the surface of temperature regulating layer 130.

[0065] The glazing unit itself is enclosed between a first glazing substrate 121 and a second glazing substrate 122.

[0066] For example, glazing unit 200 may comprise, in order: a first glazing substrate 121, a light modulator 110, a temperature regulating layer 130, an insulating layer 140, e.g., a low-pressure layer, and a second glazing substrate 122. Although not separately shown in Figure 2a, there may be additional substrates. For example, there may be a substrate between light modulator 110 and first glazing substrate 121. Similarly, there may be a substrate between insulating layer 140 and second glazing substrate 122.

[0067] In an embodiment of a glazing unit organized according to Figure 2b that has spacers in insulating layer 140 as well as in regulating layer 130, it is beneficial not to align these spacers with each other, to avoid creating a conduit for transmitting heat.

[0068] Figure 2b schematically shows an example of an embodiment of a glazing unit 201. Figure 2b differs from Figure 2a in an alternative arrangement of temperature regulating layer 130. In the example shown, light modulator 110 is between temperature regulating layer 130 and insulating layer 140. Insulating layer 140, e.g., a low-pressure layer, is arranged on a side of light modulator 110 opposite to temperature regulating layer 130. Insulating layer 140 extends across a surface of a substrate of light modulator 110 which is not in contact with temperature regulating layer 130.

[0069] The glazing unit itself is enclosed between a first glazing substrate 121 and a second glazing substrate 122.

[0070] For example, glazing unit 201 may comprise, in order: a first glazing substrate 121, a temperature regulating layer 130, a light modulator 110, an insulating layer 140, e.g., a low-pressure layer, and a second glazing substrate 122. Although not separately shown in Figure 2b, there may be additional substrates. For example, there may be a substrate between temperature regulating layer 130 and first glazing substrate 121. For example, there may be a substrate between insulating layer 140 and second glazing substrate 122.

[0071] Note that light modulator 110 may share a substrate with temperature regulating layer 130, e.g., as shown in Figure 1e, and may share a substrate with insulating layer 140. Such sharing of substrates is also possible in Figure 2a, between light modulator 110 and temperature regulating layer 130, and between temperature regulating layer 130 and insulating layer 140.

[0072] Preferably, insulating layer 140 is a low-pressure layer, also known as vacuum insulated glass (VIG). In an embodiment, the low-pressure layer has a pressure of at most 1 Pa, or at most 0.1 Pa, or at most 0.05 Pa.

[0073] The low-pressure layer reduces heat conduction across the cell gap between its enclosing substrates. By sealing a low-pressure layer between two substrates a thermal barrier is created that reduces heat conduction between the substrates. Vacuum insulated glass is useful in applications requiring thermal insulation, such as in energy-efficient windows for buildings and temperature-controlled environments in vehicles, e.g., cars.

[0074] In an embodiment of a glazing unit organized according to Figure 2b that has spacers in insulating layer 140 as well as in light modulator 110, it is beneficial not to align these spacers with each other, to avoid creating a conduit for transmitting heat.

[0075] Either option shown in Figures 2a and 2b provides heat management for light modulator 110. However, placing temperature regulating layer 130 between light modulator 110 and insulating layer 140 can be slightly more advantageous, since heat dissipation between light modulator 110 and insulating layer 140 will likely be worse than that of dissipation between light modulator 110 and glazing substrate 121.

[0076] In embodiments according to figures 2a or 2b, the temperature regulating layer has the further effect of reducing temperature difference across the glazing unit. In figure 2b, this effect is particularly advantageous, since temperature regulating layer 130 is next to glazing substrate 121, which is arranged to face to the outside, e.g., to the sun. Temperature regulating layer 130 is not only effective in regulating light modulator 110, but also glazing substrate 121. For example, glazing substrate 121, and possibly also glazing substrate 122 may be laminated glass. Laminated glass is particular vulnerable to temperature differences and benefits particularly from temperature regulating layer 130.

[0077] For example, laminated glass comprises multiple layers of glass, possibly with an interlayer, e.g., a plastic interlayer, e.g., a synthetic resin, specifically a thermoplastic, e.g., polyvinyl butyral (PVB). The interlayer may be sandwiched between glass layers.

[0078] Figure 3 schematically shows an example of an embodiment of a glazing unit 300.

[0079] Glazing unit 300 comprises a light modulator 110, a temperature regulating layer 130, and an insulating layer 140. Glazing unit 300 follows the organization of Figure 2a, but could be changed to that of Figure 2b. If glazing unit 300 is employed in the facade of a building, then 191 may denote the outside part, e.g., the part facing the sun, and 192 facing the inside, e.g., a room, an office, or the like.

[0080] Glazing unit 300 comprises, in order: - - a glazing substrate 121 - - a light modulator 110; light modulator 110 may be according to a light modulator as shown herein, possibly the light modulator of Figure 1d. The optical layer 114 of light modulator 110 may comprise spacers. - - a temperature regulating layer 130. Note that temperature regulating layer 130 is enclosed by its own substrates 131 and 132 in this example. However, either one of substrates 131 or 132, or both, could be removed from the design. Temperature regulating layer 130 also contains an optional sensor. As shown, temperature regulating layer 130 is connected to a heat sink 171. Heat sink 171 is optional or could be replaced by liquid exchange mechanism 172. - - an insulating layer 140. Insulating layer 140 is preferably a low-pressure layer. In the example shown, insulating layer 140 comprises spacers. Insulating layer 140 also comprises an optional thermoelectric element 170. Note that there is only one substrate shown between temperature regulating layer 130 and insulating layer 140. For example, this could be achieved by manufacturing these two layers together. Alternatively, an additional substrate may be included between these layers. - a glazing substrate 122

[0081] Optionally, a substrate may be introduced between glazing substrate 122 and the insulating layer. In this way it can be avoided that the glazing substrates are introduced into a low-pressure chamber. Typically, glazing substrate 121 and 122 provide mechanical stability to the glazing unit; for example, glazing substrate 121 and / or 122 may be thicker than substrates 111, 112, 131, and 132. Note that one of substrates 112 and 131 may be omitted. Also a substrate may be introduced between substrate 132 and the insulating layer 140.

[0082] Glazing unit 300 may comprise a frame 173 surrounding at least light modulator 110 and temperature regulating layer 130, and preferably insulating layer 140. Part of the frame is shown. Heat sink 171 may be integrated within the frame and thermally coupled to temperature regulating layer 130. Heat sink 171 may be configured to dissipate heat from temperature regulating layer 130 to the surrounding environment.

[0083] Optionally, one or more thermoelectric elements may be integrated within the frame and thermally coupled to temperature regulating layer 130. The thermoelectric elements are configured to harvest heat from temperature regulating layer 130 and convert the harvested heat into electrical energy.

[0084] In this embodiment, optical layer 114, temperature regulating layer 130, and insulating layer 140 may each contain spacers. Spacers are shown in optical layer 114 and insulating layer 140.

[0085] The multiple spacers arranged in the optical layer between the first and second substrates, and the multiple spacers arranged in insulating layer 140, are aligned, at least in part.

[0086] If spacers are included in temperature regulating layer 130, then it is beneficial to avoid aligning them with the spacers in insulating layer 140. Figure 3a shows a temperature regulating layer spacer 153, although there could be multiple. Note that temperature regulating layer spacer 153 is not aligned with insulating layer spacers 152.

[0087] In Figure 3a, a thermoelectric material is included between substrates 132 and 122. The thermoelectric material is configured to generate electricity from heat.

[0088] For both insulating layer 140 and temperature regulating layer 130, the spacers can be aligned with respect to some of the spacers of light modulator 110.

[0089] Light modulator 110, temperature regulating layer 130, and insulating layer 140 are mechanically protected by the glazing substrates.

[0090] Glazing unit 300 includes or may be associated with an outside sensor 162. For example, sensor 162 may measure, e.g., incident solar radiation or ambient temperature. Glazing unit 300 may include a temperature sensor 161, and an inside sensor 163. Inside sensor 163 may, for example, be located in an office or room or the like. Inside sensor 163 may be a temperature sensor. A controller 160, which may be operatively coupled to glazing unit 300, may receive input from any one of sensors 161, 162, 163. Controller 160 may further receive information on the state of light modulator 110, e.g., by measuring a current between driving electrodes in light modulator 110. Controller 160 may further have information regarding a current optical state of light modulator 110 and a desired state of light modulator 110.

[0091] Controller 160 receives information regarding the state of the glazing unit, e.g., one or more of the information described above, and may use this information to compute, or look up, an operating temperature for light modulator 110, and modulate temperature regulating layer 130 to reach the operating temperature.

[0092] For example, before and / or during an optical transition, the operating temperature may be increased; after the optical transition is complete, the operating temperature may be decreased.

[0093] In an embodiment, glazing unit 300 may comprise a matrix of temperature sensors distributed across glazing unit 300. The temperature sensor matrix comprises multiple sensors. The matrix is configured to monitor the temperature at multiple locations across the glazing unit, preferably in or close to the light modulator. For example, the matrix may be incorporated in the optical layer, the temperature regulating layer, and / or the insulating layer. In an embodiment, a temperature sensor, and in particular, the temperature sensor may be combined with spacers. The integration of these sensors within the glazing unit's structure, including possible integration with spacers, enables precise temperature management across the glazing system. This is important as there may be significant temperature differences across the glazing unit, e.g., because it may be partially shaded.

[0094] There are various ways to combine a temperature sensor with a spacer, e.g., inside an optical layer, or any of the other layers. The spacer could be a photo spacer, e.g., created using photolithography, or other deposition processes. The spacer is preferably transparent. The temperature may be a thin-film temperature sensor which may be embedded directly into or onto the body of the spacer. For example, the sensor could be a resistive temperature detector (RTD), thermistor, or a miniature thermocouple. The temperature sensor can be placed at the center or along the edges of the space. Positioning it at the center would ensure it measures the temperature of the spacer material itself, which will be in thermal contact with the surrounding medium in the optical layer. For additional data on temperature, temperature sensor could be positioned at a variety of locations, e.g., at an edge and / or at the center of a spacer; temperature sensors could be included in multiple layers. The latter provided data on heat conduction within the glazing unit. For example, if the spacer acts as a thermal bridge between two substrates, the sensor may provide real-time data on temperature gradients across the optical layer.

[0095] Conductive traces may be integrated into the spacer design, from where they connect to a controller. Conductive transparent oxides (such as ITO) could be used for wiring if transparency is critical. The embedded sensors could be connected to the controller via micro-wires or through wireless communication from the glazing unit to the controller.

[0096] The sensor may be powered by the same circuitry driving the light modulator, or by harvesting energy from ambient light or thermal differences.

[0097] The temperature data collected by the sensor matrix is transmitted to controller 160, which is operatively connected to the sensors. The controller receives multiple temperature readings and utilizes this information to adjust the temperature regulating layer and / or the light modulator. For instance, by dynamically controlling the temperature regulating layer, the controller can prevent localized overheating or undercooling, thus preserving the structural and optical integrity of the glazing unit.

[0098] In an embodiment, glazing unit 300 comprises multiple areas with independently controllable optical properties, also referred to as segments. The controller uses the temperature data from the sensor matrix to independently adjust the optical states of these areas. This capability is advantageous for example, where varying sunlight exposure or internal temperatures require differential treatment across the glazing unit.

[0099] Alternatively, or in addition, the temperature regulating layer comprises multiple areas with are independently temperature controllable. The controller uses the temperature data from the sensor matrix to independently adjust the cooling and / or heating of these areas.

[0100] The controller may be programmed to detect daily temperature cycles and anticipate these variations in its control algorithms. By predicting temperature changes based on historical data and / or current sensor readings, the system can preemptively adjust the temperature regulating layer to maintain consistent temperature.

[0101] In an embodiment, glazing unit 300 comprises a backup energy storage. The glazing unit may be configured to initiate cooling via the temperature regulating layer if the matrix of temperature sensors detects that the temperature exceeds a predetermined limit using the backup energy storage for power if needed. The backup energy storage may be charged through various means, including thermoelectric elements, photovoltaic elements, or the electrical grid. This feature protects the light modulator and the overall system from potential damage due to overheating, even in case of power shortages. The substrates used in a glazing unit and / or light modulator are typically transparent. For example, the substrates may be made from glass and / or plastic. Although, for a light modulator system, one or more of the substrate may be non-transparent, e.g., in an electrically controllable mirror, etc.

[0102] Glazing substrate 121 and / or Glazing substrate 122 may be made of glass. Various types of glass are possible, e.g., float glass, tempered glass, laminated glass, etc. Glazing substrate 121 and / or Glazing substrate 122 may be made of plastic, e.g., polycarbonate, acrylic, ETFE, etc.

[0103] The embodiment shown is double glazing, e.g., having two glazing substrates which enclose an insulating layer, e.g., insulating layer 140. In an embodiment, single glazing could be make, e.g., by omitting glazing substrate 121. This single glazing embodiment provides thermal insulation in a very thin glazing unit. Note that a disadvantage is that substrate 111 may provide less mechanical integrity than glazing substrate 121.

[0104] The embodiment shown may be extended to triple glazing and further. For example, below substrate 122, a further insulating layer(s) and a further glazing substrate(s) may be included.

[0105] Figure 4 schematically shows an example of an embodiment of a glazing unit 400. For example, the glazing unit may be organized as in Figure 3. The glazing unit further comprises a sunshade 401. The sunshade may optionally comprise a pivot 410 around which sunshade 401 may be turned, possibly under control of a controller such as controller 160. The sunshade is arranged to shadow one or more edges along the side of the window frame. This is beneficial, for example, if the temperature regulating layer is provided with a heat sink in the frame of the glazing unit. By shading the edges, it is avoided that the heat sink temperature increases due to solar radiation, or at least this is reduced.

[0106] The sunshades are also applicable if the light modulator comprises multiple segments, wherein at least part of the multiple segments have edges along a side of the window frame.

[0107] Figure 5 schematically shows an example of an embodiment of a method (500) for making a light modulator system. The method refers to light modulator system 104 shown in Figure 1e, but is applicable to other light modulator systems.

[0108] Method 500 comprises: providing 501 a heat conductive liquid on a second substrate 132 for the temperature regulating layer, pressing 502 a second substrate 112 shared between the temperature regulating layer and the light modulator against second substrate 132 for the temperature regulating layer, thus forming a temperature regulating layer; optionally, a sensor 161 may be applied to second substrate 112, optionally, before the pressing, a sealant is applied along a perimeter of second substrate 132 and / or second substrate 112, to contain the heat conductive liquid in the temperature regulating layer. The sealant may be a glue, e.g., a UV or pressure-activated glue, etc. providing 503 an optical layer on second substrate 112, pressing a first substrate 111 against second substrate 112, thus forming an optical layer, optionally, before the pressing, a sealant is applied along a perimeter of second substrate 112 and / or first substrate 111, to contain the optical layer. The sealant may be a glue, e.g., a UV or pressure-activated glue, etc.

[0109] Applying a sealant is optional. Instead of a sealant, various other ways of holding the substrates together may be used. For example, the substrates may be kept together with external means, e.g., a framework, glass solder, and the like.

[0110] To create insulating layer 140, in the form of a low-pressure layer, the following method may be followed: Introducing 504 a substrate 122 and system 104 into a low-pressure chamber, pressing substrate 122 and system 104 onto each other, optionally, before the pressing, a sealant is applied along a perimeter of substrate 122 and / or system 104 to contain the low-pressure layer; the sealant may be a glue, e.g., a UV or pressure-activated glue, etc.

[0111] An advantage of using a low-pressure chamber for making the low-pressure layer is that no evacuation port is needed.

[0112] As explained in European patent applications EP24177302.7 and EP24194098.0, it is advantageous to apply a barrier to substrate 122 and / or system 104 to contain the sealant and to avoid the sealant being pushed inside the insulating layer due to atmospheric pressure before the sealant has hardened.

[0113] A light modulator system as in an embodiment may be advantageously combined with a light modulator in various ways. Below various types of light modulators are discussed than can be combined with a temperature regulating layer, and / or may be included in vacuum insulated glass.

[0114] Dynamic glazing, also known as smart glazing, may comprise a system wherein the transparency or optical properties of a glazing material are altered in response to an external electrical input. This system may allow for active control over light and heat transmission, thereby enhancing energy efficiency and user comfort in various architectural or vehicular applications. Advantageously, the dynamic glazing is combined with a low-pressure layer.

[0115] A low-pressure layer is very advantageous as in this way a very thin glazing unit may be obtained; it is not necessary though, a low-pressure layer may be replaced with any conventional insulating layer, e.g., as used in conventional glazing units.

[0116] Figures 6a-9c provide various examples of the electrode system on the first and second substrate and how they may be implemented or used in a light modulator.

[0117] Some of the known light modulators which may be provided with a temperature regulating layer and / or a low-pressure layer are based on the electrophoretic principle. For example, the substrate may comprise multiple interdigitated electrodes applied to the substrate, e.g., two electrodes, each of the multiple electrodes being arranged in a pattern across the substrate, the multiple interdigitated electrodes being arranged alternatingly with respect to each other on the substrate. Having multiple interdigitated electrodes allows local control over the electric field enabling electrophoretic control of particles.

[0118] Electrophoretic light modulators are explained more extensively herein and are used as the motivating example. In an embodiment, a light modulator comprises a first substrate and a second substrate. At least one of the first and second substrates may be according to an embodiment and may be provided with temperature regulating layer and / or a low-pressure layer. For example, the first and second substrates may be arranged with inner sides opposite to each other, using a substrate according to an embodiment. An optical layer is arranged between the first and second substrates. The electrode is arranged to modulate an electrical field in the optical layer. The optical layer comprises a fluid, e.g., liquid, comprising particles, wherein the particles are electrically charged or chargeable. The particles may be moved under control of the electrical field. For example, a controller may be configured to apply an electric potential to the electrode to obtain an electric field at the electrode providing electrophoretic movement of the particles towards or from one of the at least one electrode causing modulation of the optical properties of the light modulator. For example, optical properties may include a transition between a high-transparent state and a low-transparent state or vice versa. Note that a transition may also alter thermal properties of the light modulator.

[0119] Below a number of known light modulators are reviewed, showing some of the options in technology and electrodes. These known light modulators can advantageously be combined with temperature regulating layer and / or a low-pressure layer, optionally sharing a substrate between the vacuum-insulated part and light modulator part.

[0120] These examples also show light modulators with varying numbers of electrodes on a substrate.

[0121] International patent applications WO2011012499 A1 (included herein by reference) and WO2011131689 (included herein by reference) disclose light modulators in the form of electrophoretic display devices, e.g., e-Ink displays. A pixel of the display comprises an accumulation electrode and a field electrode, the accumulation electrode being arranged at a storage area for accumulating charged particles away from an aperture area, and the field electrode occupying a field-electrode area being at least a part of an aperture area of the pixel, the charged particles being movable between the accumulation electrode and the field electrode. In an embodiment, two electrodes are applied on a single substrate. These electrophoretic display devices may be provided with temperature regulating layer and / or a low-pressure layer, e.g., arranged in parallel to the electrophoretic display device. The electrophoretic display devices, temperature regulating layer, and / or low-pressure layer advantageously may share a common substrate, although this is not necessary.

[0122] US patent 10921678 with title 'Electrophoretic device', included herein by reference, shows an electrophoretic device having only one patterned electrode on one of two substrates. For example, the one substrate with an electrode according to US 10921678 may be replaced with a substrate according to an embodiment comprising one single electrode. For example, an embodiment comprises a first transparent substrate with a field electrode and a second substrate opposite the first substrate, with an accumulation electrode. The first substrate and the second substrate enclose a pixel with a fluid and particles. In use, an applied electric field to the field electrode and the accumulation electrode provides movement of the particles from the field electrode to the accumulation electrode and vice versa. Any of these cited electrophoretic or dielectrophoretic light modulators may be adapted by including a temperature regulating layer and / or one or more low-pressure layers according to an embodiment.

[0123] US patent 8054535B2 (included herein by reference) and US patent 8384659b2 (included herein by reference) show alternative examples of electrophoretic light modulators in one of two substrates having two patterned electrodes.

[0124] Patterned electrodes are also used in dielectrophoretic light modulators. For example, US patent application US2005185104A1 (included herein by reference) and US20180239211A1 (included herein by reference) show dielectrophoretic light modulators having a substrate with a patterned electrode. Any of these cited electrophoretic or dielectrophoretic light modulators may be adapted by including a temperature regulating layer and / or one or more low-pressure layers areas according to an embodiment.

[0125] The paper "Reversible Metal Electrodeposition Devices: An Emerging Approach to Effective Light Modulation and Thermal Management," included by reference, also shows a substrate on which a patterned electrode is applied. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0126] An embodiment of a substrate may be used in an electrochromic device (ECD). An electrochromic device (ECD) controls optical properties such as optical transmission, absorption, reflectance, and / or emittance in a continual but reversible manner on application of voltage (electrochromism). This property enables an electrochromic device to be used for applications like smart glass, electrochromic mirrors, and electrochromic display devices. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0127] An electrochromic device is described, e.g., in the paper "Silver grid electrodes for faster switching ITO free electrochromic devices" by António Califórnia et al., included herein by reference. The paper describes the preparation of an electrochromic device, in this case, one which is ITO-free. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0128] An electrochromic device uses electrically conductive electrodes applied on a substrate. The cited paper uses silver grids, made using silver ink, as electrically conductive electrodes. An electrochromic device may comprise an electrochromic material. The cited paper uses poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). In an electrochromic device, at least one electrode, e.g., the electrically conductive electrode, is applied to a substrate. The electrode being arranged in a pattern across the substrate. The cited paper discloses two different grid patterns: a regular hive and a regular ladder design. See table 1 and figure 3 of the cited paper. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0129] Electrodes may be applied to a substrate by screen-printing on a substrate, in the case of the cited paper, polyethylene terephthalate (PET). The electrodes are typically an electrically conductive material, e.g., a metal or metal oxide. In the cited paper, silver ink was used to screen print the grids on PET using a RokuPrint RP 2.2 equipment and a 180 wired mesh. The samples were allowed to dry in an oven at 130°C for 15 min. On top of these silver grids, one or two layers of PEDOT:PSS SV3 were posteriorly printed by screen printing. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0130] Another example of an electrochromic device is given in US patent 5161048, with title "Electrochromic window with metal grid counter electrode and acidic polyelectrolyte", included herein by reference. For example, an electrochromic device may comprise a transparent electrochromic film and an ion-conductive layer disposed between a pair of electrodes. The metal grid electrode is used for the electrodes. Figure 1 of the patent shows a metal grid according to the cited patent. To form the counter electrode, a metal grid is disposed adjacent to the second glass substrate.

[0131] For example, in an embodiment of an electrochromic device, the electrochromic device may comprise a transparent substrate, an electroconductive electrode member, a transparent electrochromic film in contact with said electroconductive electrode member, an ion-conductive polymer in contact with said electrochromic film; and a patterned conductive electrode in contact with said ion-conductive polymer. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0132] A substrate according to an embodiment can be beneficially applied in several other technologies. For example, the light modulator may be a dielectrophoretic light modulator, e.g., as shown in US20050185104 A1, included herein by reference. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0133] A substrate as in an embodiment may also be used in other electrowetting and OLED applications. In OLED and electrowetting, electrodes are needed on only one of the substrates. The substrate with electrodes may be according to an embodiment including a low-pressure layer and / or a temperature regulating layer.

[0134] Yet other dynamic glass technologies may be used.

[0135] For example, an optical layer for a light modulator, e.g., in dynamic glazing, may use LCD (Liquid Crystal Display) technology. For example, the optical layer may comprise liquid crystal molecules that can be aligned to control the amount of light passing through the display. When an electric current is applied to the liquid crystal molecules, they change their alignment and modify the way that light passes through the material. The optical layer with LCD material may be placed between two layers of glass or plastic and connected to an electrical circuit. By controlling the electric current applied to the LCD material, the amount of light passing through the glazing may be adjusted. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0136] An optical layer for a light modulator, e.g., in dynamic glazing, may use Suspended Particle Device (SPD) technology. The optical layer may comprise particles suspended within a thin film or laminate. By applying an electrical current to the SPD film, the particles align and modify the amount of light passing through the material, allowing for dynamic control of the glazing. When the electrical current is turned off, the suspended particles randomize and allow more light to pass through, creating a clear or transparent effect. When the electrical current is turned on, the particles align and absorb more light, creating a darker or tinted effect. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0137] In an application of a light modulator system for glazing, both substrates are typically transparent. In other applications, e.g., in television, e-readers, etc., only one substrate may be transparent.

[0138] Figure 6b schematically shows an example of an embodiment of a substrate. The substrate is particularly useful for use in a light modulator, e.g., of a kind described herein. Across the substrate, an electrode system is applied in the form of multiple interdigitated electrodes. Shown in figure 6b are two interdigitated electrodes.

[0139] The motivating example use of the substrate is in an electrophoretic light modulator. Typically, an electrophoretic light modulator comprises at least two substrates, each having at least two electrodes at each of the substrates; this is not necessary though, for example, an electrophoretic light modulator may comprise a single substrate with 2 electrodes and an opposite substrate with 1 electrode. In any case, preferably, at least one of the substrates in the light modulator is according to an embodiment.

[0140] An embodiment of a light modulator comprises a first substrate according to an embodiment and a second substrate. The first and second substrates are arranged with inner sides opposite to each other. At least one electrode is applied to the inner side of the first substrate. An optical layer is arranged between the first and second substrates. A controller is configured to apply an electric potential to the at least one electrode causing modulation of the optical properties of the light modulator. One or both of the first and second substrates are transparent and / or translucent.

[0141] There are many different kinds of light modulators that use at least one electrode applied to a substrate. The optical layer and controller may be arranged to modulate optical properties using effects that depend on the potential on the electrode; examples include the dielectrophoretic effect and the electrophoretic effect. For example, optical modulation may comprise the modulation of particles arranged in the optical layer. The number of electrodes may range from one on a single substrate, to multiple electrodes on one or both substrates.

[0142] The optical layer arranged between the first and second substrates may comprise particles, e.g., suspended in a fluid. The controller may be configured to apply an electric potential to the electrodes causing the particles to move thus modulating the optical properties of the light modulator.

[0143] In an embodiment, the particles comprise electrically charged or chargeable particles, and the controller is configured to apply an electric potential to the electrode to obtain an electric field providing electrophoretic movement of the particles. In an embodiment, the electric field is arranged between at least two electrodes arranged on the same substrate or arranged on different substrates.

[0144] In an embodiment, the particles comprise dielectric particles, and the controller is configured to apply an electric potential to the electrode to apply an electric field gradient to the particles enabling the particles to be moved under the action of dielectrophoretic forces.

[0145] The controller may apply an electric signal to one or more of the electrodes. Embodiments that control dielectrophoretic forces may use a signal that comprises a DC signal and / or an AC signal. Embodiments that control electrophoretic forces may use a signal that comprises a DC signal and / or an AC signal.

[0146] Shown in figure 6b are two electrodes on the same surface. The two electrodes are indicated in figure 6b in two different dashing styles. There could be more than two electrodes on the same side of the substrate, e.g., to facilitate more fine-grained control of voltage differences across the substrate. The electrodes are applied to a same side of the substrate. Applying electrodes to a substrate may be done lithographically, e.g., using a mask representing the electrode(s) pattern. Electrodes may also be applied by embedding them in the substrate.

[0147] An electrode is electrically connected, e.g., has the same electric potential everywhere. An electrode may comprise a driving bus and main lines. At least, the main lines are interdigitated with main lines of a further electrode. Typically, the electrodes extend in a substantially straight line across the substrate, while the main lines are convoluted.

[0148] In an embodiment, the two substrates of a light modulator each have two electrodes arranged at their inner surface. Though, as mentioned, multiple electrodes on one or both substrates are not needed. For example, an embodiment of a light modulator comprises a first substrate and a second substrate. For example, the first substrate may comprise one electrode, the second substrate may not comprise electrodes. For example, the first substrate may comprise two electrodes, the second substrate may comprise one electrode. For example, the first substrate may comprise two electrodes, the second substrate may comprise two electrodes. For example, the first substrate may comprise more than two electrodes, the second substrate may comprise two or more electrodes.

[0149] Light modulators, wherein each substrate comprises two electrodes are used as a motivating example, though. Designs of substrates featuring two electrodes may be adapted to have a single electrode, e.g., by connecting the two electrodes, or by removing one of the electrodes. Adapting a substrate in such a manner may make it suitable for use in different technologies.

[0150] Each of the multiple electrodes is arranged in a pattern across the substrate. The multiple electrodes are arranged alternatingly with respect to each other on the substrate. Typically, an electrode comprises multiple main lines, that each stretch across the substrate. The main lines of the electrodes alternate, e.g., interdigitate. For example, in figure 6b the first electrode comprises main lines 611-614, and the second electrode comprises main lines 621-624. The electrodes are each driven by its driving bus. Figure 6b shows two driving buses: driving bus 610 and driving bus 620. The electrodes also serve to connect the main lines together. For example, in figure 6b, the driving bus 610 drives and connects main lines 611-614; and the driving bus 620 drives and connects main lines 621-624. There can be more main lines than the four shown in this example. The use of main lines is advantageous as it reduces the length of the electrodes, but it is not necessary. A design using only one main line per electrode is not impossible, though having multiple is advantageous.

[0151] The driving buses may be adapted to form a contact area to enable electrical connection to at least the one or more driving electrodes applied on the first substrate, e.g., a connection from outside the light modulator. This is not necessary, and a separate contact area, e.g., additional to driving buses 610 and 620 may be provided in an embodiment.

[0152] The multiple main lines of the first and second electrodes are arranged alternatingly with respect to each other on the substrate.

[0153] In this example, there are no other connections between the main lines of an electrode than through the common driving bus. In an embodiment, an electrode comprises a mesh electrode, that is, it may have additional electrical connections added between electrode lines of the same electrode. This increases the reliability of the electrode. Such additional connections typically cross an electrode line of another electrode, which may be resolved by placing the additional electrical connection in part on a different level with respect to the substrate than the electrode line being crossed. For example, one may place the entire electrodes at a different level than another electrode. In this way, additional connections may be placed without short circuits arising.

[0154] A motivating application for a substrate such as substrate 600 is in smart glazing, e.g., a light modulator, which may be applied in domestic housing, offices, greenhouses, cars, and the like. The level of transparency or reflectivity of the smart glazing can be adapted electrically. For example, in smart glazing, two substrates such as substrate 600 would be stacked so that the sides on which the two electrodes are applied face each other. A fluid with particles is enclosed between the two substrates. Smart-glazing embodiments are further discussed below. In an embodiment, electrodes, e.g., two or more electrodes are applied to one surface of each substrate. There could also be one, two, or more electrodes on the other surface of substrate 600, e.g., to facilitate stacking of three or more substrates. For example, substrate 600 may be used for substrate 360 and one of substrates 310 and 320.

[0155] Some embodiments below show examples of modulating a transparency or reflectivity level. Light modulators may be adapted for other optical effects. For example, if desired, embodiments could be modified to different levels of translucency instead of different levels of transparency. If desired, the type of particle that is used in an embodiment can be varied, e.g., to particles that differ in which wavelengths they absorb or reflect, and how specular or diffuse the reflection is. For example, in an embodiment, a light modulator can modulate different levels of reflection. Particles can also emit light. Stacking multiple optical layers further increases the possibilities.

[0156] Having two sets of alternating main lines is sufficient to provide electrically adaptable glazing; due to the alternating two sets, the electric field at any part of the substrate can be controlled as two opposite electrodes border the part from two opposing sides.

[0157] Interestingly, the pattern in which the electrodes stretch across the substrate may be created by multiple repeated building blocks. Shown in figure 6b, the electrodes on substrate 600 show four blocks: blocks 641, 642, 643, and 644 which are all substantially the same. The number of building blocks may be larger than four. The building blocks repeat in both directions across the substrate, e.g., a first direction 691, e.g., an x-direction, shown horizontally in the figure, and a second direction 692, e.g., a y-direction, shown vertically in the figure. Using building blocks is advantageous as it allows manufacture using a stepper machine; using building blocks is not necessary.

[0158] For example, figure 6a schematically shows an example of an embodiment of a building block 640. Building block 640 comprises multiple interdigitated electrodes extending in at least 2 directions across the building block. Shown in figure 6a are four electrodes: electrode 631-634. When the building blocks are repeated across a substrate in two directions, the electrodes in the building block will form the electrodes, e.g., form the multiple main lines of the electrodes.

[0159] The electrodes that are formed by repeating building blocks are connected to the driving buses. Typically, electrode lines in a building block are connected to electrode lines in neighboring blocks by merging corresponding electrode lines; this is not necessary though, between repeated building blocks, connection zones can be inserted that connect corresponding electrode lines.

[0160] This step can connect up multiple main lines together, thus forming a single electrode. Figure 6b shows two connecting zones 619 and 629 in which the main lines belonging to the same electrode are connected to driving bus 610 and driving bus 620, respectively.

[0161] Figures 7a-7f schematically show examples of substrates with interdigitated electrodes. These may be embodied on a substrate with two electrodes, e.g., by alternatingly connected electrodes. Figures 7a-7d may also be embodied on a substrate with multiple electrodes, e.g., by connecting in sequences of 3 or 4 or more electrodes.

[0162] Figures 7e and 7f show designs with two electrodes on the surface of the substrate. Either design could be modified to have only a single electrode on the surface of the substrate, e.g., by removing one of the two electrodes. For example, such a modified design could be used in a light modulator that uses a substrate with a single electrode.

[0163] The designs shown can be realized in a single plane, without having crossing electrodes. In particular, if these designs are connected to two driving buses, no crossing electrodes are needed. When more than two electrodes are used, or if more complicated electrode patterns are used, then crossing of the electrodes may be used, or may even become necessary. Such crossings are possible however for example, at the location where two electrode lines cross, a dielectric material may be arranged between the electrodes. For example, such an insulator may be deposited at the crossing location. For example, a first electrode is in a first plane of the substrate and a second electrode is in a second plane of the substrate.

[0164] Two substrates according to an embodiment may be combined to form a light modulator. The light modulator is particularly suited to glazing. An exemplary embodiment of a light modulator is shown below.

[0165] Figure 8a schematically shows an embodiment of a light modulator 10, which may be applied in smart glazing.

[0166] Reference is made to patent application PCT / EP2020 / 052379, which is included herein by reference; this application comprises advantageous designs for light modulators, which may be further improved, e.g., by including electrodes, building blocks, and / or substrates as explained herein.

[0167] Light modulator 10 can be switched electronically between a transparent state and a non-transparent state and vice versa, or between a non-reflective state and a reflective state and vice versa. Light modulator 10 comprises a first substrate 11 and a second substrate 12 arranged opposite to each other. On an inner side of first substrate 11, at least two electrodes are applied: shown are electrodes 13a, 13b. These at least two electrodes are together referred to as electrodes 13. On an inner side of second substrate 12, at least two electrodes are applied: shown are electrodes 14a, 14b. These at least two electrodes are together referred to as electrodes 14. One or more of substrates 11 and 12 may be provided with one or more contact areas to enable electrical connection to at least the one or more electrodes applied on the substrate(s).

[0168] A fluid 15 is provided between said substrates. The fluid comprises particles 30, e.g., nanoparticles and / or microparticles, wherein the particles are electrically charged or chargeable. For example, particles may carry a charge on their surface intrinsically. For example, the particle may be surrounded by a charged molecule. The fluid may be a liquid.

[0169] The electrodes are arranged for driving particles 30 to move towards or away from electrodes, depending on the electric field applied. The optical properties, in particular the transparency or reflectivity of the light modulator, depend on the location of particles 30 in the fluid. For example, a connection may be provided for applying an electric field to the electrodes.

[0170] At least one, but preferably both electrodes 13 and 14 are according to an embodiment, though they are shown schematically in the figures.

[0171] In an example, substrate 11 and substrate 12 may be optically transparent outside of the electrodes, typically >95% transparent at relevant wavelengths, such as >99% transparent. Taking electrodes into account, transparency can be much lower, e.g., 70%. The term "optical" may relate to wavelengths visible to a human eye (about 380 nm- about 750 nm), where applicable, and may relate to a broader range of wavelengths, including infrared (about 750 nm - 1 µm) and ultraviolet (about 10 nm-380 nm), and sub-selections thereof, where applicable. In an exemplary embodiment of the light modulator, a substrate material is selected from glass, and polymer.

[0172] In another example, one substrate, such as a bottom substrate 12, may be reflective or partially reflective, while the top substrate 11 is transparent. The optical properties, in particular the reflectivity of the light modulator, depend on the location of particles 30 in the fluid. When the panel is in the open state (vertical drive), the particles will mostly be located between opposite electrodes of the two substrates, such that incident light can pass through the transparent top substrate and the optical layer relatively unhindered and is reflected or partially reflected on the bottom substrate.

[0173] The distance between the first and second substrates is typically smaller than 30 µm, such as 15 µm. In an exemplary embodiment of the light modulator a distance between the first and second substrates is smaller than 500 µm, preferably smaller than 200 µm, preferably less than 100 µm, even more preferably less than 50 µm, such as less than 30 µm.

[0174] In an example, the modulator may be provided in a flexible polymer, and the remainder of the device may be provided in glass. The glass may be rigid glass or flexible glass. If required, a protection layer may be provided on the substrate. If more than one color is provided, more than one layer of flexible polymer may be provided. The polymer may be polyethylene naphthalate (PEN), polyethylene terephthalate (PET) (optionally having a SiN layer), polyethylene (PE), etc. In a further example, the device may be provided in at least one flexible polymer. As such, the modulator may be attached to any surface, such as by using an adhesive.

[0175] Particles 30 may be adapted to absorb light and thereby prevent certain wavelengths from passing through. Particles 30 may reflect light; for example, the reflection may be specular, diffusive, or in between. A particle may absorb some wavelengths and reflect others. Particles may also or instead emit light, e.g., using phosphorescence, fluorescence, or the like. Even the fluid may emit light, whose emittance is modulated by changing the location of particles.

[0176] In an exemplary embodiment of the light modulator, a size of the nanoparticles is from 20-1000 nm, preferably 20-300 nm, more preferably smaller than 200 nm. In an exemplary embodiment of the light modulator, the nanoparticles / microparticles may comprise a coating on a pigment, and preferably comprise a core. In an exemplary embodiment of the light modulator, the coating of the particles is made from a material selected from conducting and semiconducting materials.

[0177] In an exemplary embodiment of the light modulator, the particles are adapted to absorb light with a wavelength of 10 nm-1 mm, such as 400-800 nm, 700 nm to 1 µm, and 10-400 nm, and / or are adapted to absorb a part of the light with a wavelength-range falling within 10 nm-1 mm (filter), and combinations thereof.

[0178] In an exemplary embodiment of the light modulator, the particles are electrically charged or chargeable. For example, a charge on the particles may be 0.1e to 10e per particle (5*10 -7< -0.1C / m 2< ).

[0179] In an exemplary embodiment of the light modulator, the fluid is present in an amount of 1-1000 g / m 2< , preferably 2-75 g / m 2< , more preferably 20-50 g / m 2< , such as 30-40 g / m 2< . It is a big advantage that with the present layout much less fluid, and likewise particles, can be used.

[0180] In an exemplary embodiment of the light modulator, the particles are present in an amount of 0.01-70 g / m^2, preferably 0.02-10 g / m^2, such as 0.1-3 g / m^2.

[0181] In an exemplary embodiment of the light modulator, the particles have a color selected from cyan, magenta, and yellow, and from black and white, and combinations thereof.

[0182] The light modulator can be also configured to only, or primarily, modulate non-visible light such as UV or near-IR, e.g., respectively in the range of about 10 nm-380 nm, and in the range of about 750 nm - 1 µm.

[0183] In an exemplary embodiment of the light modulator, the fluid comprises one or more of a surfactant, an emulsifier, a polar compound, and a compound capable of forming a hydrogen bond.

[0184] Fluid 15 may be an apolar fluid with a dielectric constant less than 15. In an exemplary embodiment of the light modulator, the fluid has a relative permittivity εr of less than 100, preferably less than 10, such as less than 5. In an exemplary embodiment of the light modulator, fluid 15 has a dynamic viscosity of above 10 mPa.s.

[0185] Electrodes 13a, 13b and electrodes 14a, 14b are in fluidic contact with the fluid. The fluid may be in direct contact with the electrodes, or indirectly, e.g., the fluid may contact a second medium with the electrode, such as through a porous layer. In an embodiment, the electrodes cover about 1-30% of the substrate surface. In an embodiment, the electrodes comprise an electrically conducting material with a resistivity of less than 100 nS2m (at 273K; for comparison, typically used ITO has 105 nS2m), which is similar to an electrical conductivity >1*10 7< S / m at 20°C).

[0186] In an embodiment of the light modulator, electrodes comprise copper, silver, gold, aluminum, graphene, titanium, indium, and combinations thereof, preferably copper. The electrodes may be in the form of microwires embedded in a polymer-based substrate; for example, copper microwires.

[0187] A connection for applying an electric field to the electrodes, wherein the applied electric field to the electrodes provides movement of the nano- and microparticles from a first electrode to a second electrode and vice versa. A connection for applying an electric field to the electrodes may be provided. For example, in an exemplary embodiment of the light modulator, an electrical current is between -100 to +100 µA, preferably -30 to +30 µA, more preferably -25 to +25 µA. For example, a power provider may be in electrical connection with the at least two electrodes. The power provider may be adapted to provide a waveform power. At least one of amplitude, frequency, and phase may be adaptable to provide different states in the light modulator. For example, these aspects of the power may be adapted by a controller 16. The controller 16 may be connected to one or more contact areas of the light modulator.

[0188] Light modulator 10 may comprise one or more segments, a segment being a single optically switchable entity, which may vary in size. The substrates enclose a volume, which may be a segment, at least partly.

[0189] The present device may comprise a driver circuit for changing the appearance of (individual) segments by applying an electric field. As such also the appearance of the light modulator, or one or more parts thereof, may be changed. For example, a segment may have an area of at least 1 mm 2< . The present design allows for stacking to allow for more colors; e.g., for full-color applications, a stack of two or three modulators could provide most or all colors, respectively.

[0190] Having one or more segments allows the light modulator to be controlled locally; this is advantageous for some applications but not necessary. For smart glazing, a light modulator may be used with or without segments. For example, applied in smart glazing, transparency or reflectivity may be controlled locally, e.g., to block a sun-patch without reducing transparency or reflectivity in the whole window. Segments may be relatively large, e.g., having a diameter of at least 1 mm, or at least 1 cm, etc.

[0191] In an exemplary embodiment of the light 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 to be opposite each other. In aligned substrates, electrodes on different substrates fall behind each other when viewed in a direction orthogonal to the substrates. When the light modulator is disassembled, and the substrates are both arranged with electrodes face-up, then the electrode patterns are each other's mirror image.

[0192] Aligning substrates may increase the maximum transparency or reflectivity of the light modulator. On the other hand, when selecting a light modulator for more criteria than the range of transparency or reflectivity, etc., it may be better not to align or not fully align the two substrates. Light modulators can be stacked. For example, two stacked light modulators can be made from three substrates, wherein the middle one has electrodes on both its surfaces. In an embodiment of the light modulator, optionally at least one substrate 11,12 of a first light modulator is the same as a substrate 11,12 of at least one second light modulator. For stacked modulators, alignment may also increase maximum transparency or reflectivity, but it may be detrimental to other considerations, e.g., diffraction.

[0193] Figure 8b schematically shows an example of an embodiment of a light modulator 40. Light modulator 40 is similar to light modulator 10, except that it comprises multiple optical layers; in the example as shown, two optical layers. There may be more than two optical layers. Each optical layer is arranged between two substrates. Light modulator 40 can be regarded as a stack of two-substrate light modulators as in figure 8a. As shown, light modulator 40 comprises three substrates: first substrate 41, second substrate 42, and third substrate 43. Between substrates 41 and 42 is an optical layer, and between substrates 42 and 43 is an optical layer. The optical layers may be similar to those in light modulator 10. A controller 46 is configured to control the electrical current on the electrodes of the substrates. For example, in figure 8b, controller 46 may be electrically connected to at least 4 times 2 equals 8 electrodes.

[0194] Interestingly, the particles in the multiple optical layers may be different so that the multiple layers may be used to control more optical properties of the light modulator. For example, particles in different optical layers may absorb or reflect at different wavelengths, e.g., may have a different color. This can be used to create different colors and / or different color intensities on the panel by controller 46. For example, a four-substrate panel may have three optical layers with different color particles, e.g., cyan, yellow, and magenta, respectively. By controlling the transparency or reflectivity for the different colors, a wide color spectrum may be created.

[0195] The surfaces of the substrates that face another substrate may be supplied with two or more patterns, e.g., as in an embodiment. For example, the outer substrates 41 and 43 may receive electrodes only on an inner side, while the inner substrate, e.g., substrate 42, may have electrodes on both sides.

[0196] Substrates 41 and 42 may together be regarded as an embodiment of a light modulator. Likewise, substrates 42 and 43 may together be regarded as an embodiment of a light modulator. One or more of substrates 41, 42, and 43 may be provided with a contact area to connect to the electrodes.

[0197] Figure 8c schematically shows an example of an embodiment of a car 20 having smart glazing for windows 21. This is a particularly advantageous embodiment since, while driving, the level of incident lighting can change often and rapidly. Using smart glazing in a car has the advantage that light levels can be maintained at a constant level by adjusting the transparency of the car windows. Moreover, the reduced diffraction effect improves safety as it reduces driver distraction. Car 20 may comprise a controller configured for controlling the transparency or reflectivity of windows 21. Smart glazing can also be used in other glazing applications, especially where the amount of incident light is variable, e.g., buildings, offices, houses, greenhouses, and skylights. Skylights are windows arranged in the ceiling to allow sunlight to enter the room.

[0198] The light modulator may have two optical states, e.g., a transparent state and a non-transparent state, or a non-reflective state and a reflective state. The light modulator, e.g., light modulator 10 or light modulator 40, may be configured to switch to the second optical state, e.g., the non-transparent state or to the reflective state by creating an alternating voltage on at least one of the first and second substrates, applying an alternating current between at least a first electrode and a second electrode on the first substrate and / or between a first electrode and a second electrode on the second substrate, and switch to the first optical state, e.g., the transparent state or to the non-reflective state by creating an alternating voltage between the first and second substrate, applying an alternating current between a first electrode on the first substrate and a first electrode on the second substrate, and / or between a second electrode on the first substrate and a second electrode on the second substrate.

[0199] The light modulator may also demonstrates multiple intermediate transparency states between the 2 optical states. For example, the light modulator may support a gray scale of transparency states between a maximally transparent and maximally opaque state. The same holds for other optical properties, e.g., intermediate reflective properties.

[0200] The electrode pattern on the first substrate is arranged at least in part in the same pattern as a second electrode on the second substrate. Typically, the electrodes oppose each other, but the pattern of the first electrode and second electrode may also be shifted with respect to each other.

[0201] A protective coating may be provided on at least a part of the inner surface area of at least one of the first substrate and the second substrate. A driving signal applied to electrodes typically has a varying voltage. For example, a power provider may be operated at an AC frequency for switching to a transparent state or to a non-transparent state. Such a signal may have a frequency between, say, 1-1000 Hz. A balanced electrolysis current may be obtained by continuously switching the polarity of oppositely charged electrodes on the first and on the second substrates and / or between the first and the second substrates.

[0202] Figures 9a-9b schematically show a side view of an embodiment of a light modulator in use. In this figure, only the electrodes are shown.

[0203] Applying an electric field to the electrodes on the substrates causes an electrical force on the particles. Using this effect, the particles can be moved around, and so different transparency or reflectivity states can be caused in the light modulator. A controller may control the electric field, e.g., its amplitude, frequency, and phase. In an embodiment, the controller is connected to at least four electrodes: two for each substrate. But more electrodes may be used and connected to the controller; for example, more than 2 electrodes may be used for a substrate to better fine-tune grayscaling and driving to a non-transparent or reflective state. Multiple electrodes may also be used to support multiple segments on the substrate.

[0204] Figure 9a shows the light modulator without an electric field being applied. No electric force is yet applied on particles 30 suspended in fluid 15, in figure 9a.

[0205] In the configuration shown in figure 9a, a conducting electrode pattern, arranged on the top substrate, is completely or substantially aligned with a conducting electrode pattern on the bottom substrate. The conducting electrode pattern may be deposited on a transparent or (partially) reflective glass substrate or may be embedded in a plastic substrate, etc.

[0206] Alignment between the top-electrode pattern and the bottom electrode pattern contributes to a wider range of achievable levels of transparency or reflectivity. However, alignment is not needed, as similar effects can be obtained without alignment. Without alignment, a range of transparency or reflectivity is likewise obtained.

[0207] Note that in these examples, reference is made to the top substrate and the bottom substrate to refer to the substrate that is higher or lower on the page. The same substrates could also be referred to, e.g., as the front substrate and back substrate, since in a glazing application, the substrates would be aligned vertically rather than horizontally.

[0208] Figure 9b shows the light modulator wherein, say at an instance P1, a potential +V1 is applied to each microwire electrode on the top substrate, while a negative voltage, say -V1, is applied to each microwire electrode of 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 electrodes 14. The difference in potential causes negatively charged particles to flow to the vicinity of the electrodes of the top substrate, where the particles will substantially align with the top electrodes. As a result, if both the top and bottom substrates are transparent, the transparency of light modulator 10 will increase. Likewise, if, e.g., the top substrate is transparent and the bottom substrate is reflective, the reflectivity of light modulator 10 will increase. If the solution contains positively charged particles, they will flow to the vicinity of the electrodes of the bottom substrate, where those particles will substantially align with the bottom electrodes.

[0209] A similar transparency can be achieved when in a second instance, P2, of the on-state, the voltages of the top electrodes and bottom electrodes are reversed in contrast to the instance of P1. In the instance P2, the voltage of each electrode on the top substrate is now supplied with a negative potential -V1 while the voltages of the aligned electrodes of the bottom substrate are supplied with a positive potential. This state is similar to the state shown in figure 9b, but with top and bottom substrates reversed. In this configuration, the transparency of light modulator 10 is also high. If reflective particles are used, then reflectivity is low.

[0210] Interestingly, by switching between a positive potential at electrodes at the top substrate, e.g., as shown as electrodes 13 in figure 9b (and a negative potential on electrodes 14), and a positive potential at electrodes at the bottom substrate, e.g., as shown as electrodes 14 in figure 9b, the transparency or non-reflectivity can be maintained, while decreasing corrosion damage to the electrodes. This alternating electric field can be achieved by applying alternating electric potentials to the top and bottom electrodes.

[0211] Applying an AC waveform is optional, but it is a useful measure to increase the lifetime of the light modulator by reducing corrosion. Corrosion can form, for example, when using copper electrodes, since copper ions dissolve in an ionic fluid at one substrate and flow to electrodes on the opposite substrate, where they deposit. By applying a waveform, the direction of copper ion transport is frequently reversed, thus reducing corrosion damage. Between the two instances P1 and P2, the corrosion current between the two substrates is balanced or substantially, e.g., >95%, balanced, e.g., as corrosion rate of an electrode of the top plate occurs, there is a balancing deposition of copper on the bottom electrode between each instance of time, P1, and vice versa in instance P2. Therefore, the particles are transitioning or migrating continuously between top and bottom electrodes, and the light modulator or smart window is always in the on-state while the dynamic electrolysis current between the top and bottom electrodes is constant, thus there is no or a negligible net loss of electrode material on the top and bottom substrates.

[0212] Figure 9c shows how a state of decreased transparency or increased reflectivity can be obtained. An alternating voltage is applied on the same substrate. For example, in an embodiment, a potential +V2 is applied to a first electrode and the next immediate neighboring electrode has an opposite potential -V2 etc., as shown in fig. 8c. This can be obtained by applying the potential +V2 to electrode 13a and the opposite potential -V2 to electrode 13b. On the opposite substrate, the potential +V2 may be applied to electrode 14a and the opposite potential -V2 to electrode 14b. For example, the electrodes may be arranged so that the electrodes on the substrates are aligned; an electrode on the top substrate having an opposite electrode on the bottom substrate, and vice versa. For example, to decrease transparency or increase reflectivity, the opposite electrode may receive the same potential, while neighboring electrodes receive an opposite potential. An embodiment is shown in figure 9c, wherein four electrodes are indicated with the reference numbers 13a, 13b, 14a, and 14b, and the rest of the electrodes continue to alternate.

[0213] By using this AC drive cycle between top and bottom substrates, diagonal and lateral electric fields are generated between the two substrates thereby causing haphazard diffusion of the particles, thereby creating the closed state of the light modulator. As a result of this configuration, the particles migrate diagonally and laterally between the top and bottom substrates and diffusion of particles into the visible aperture of the light modulator contributes to the closed, opaque state of the light modulator.

[0214] As for the transparent state shown in figure 9b, a waveform may be applied to the electrodes, e.g., so that electrodes that are shown in figure 9b with a positive potential become negative and vice versa. As in figure 9b, applying a waveform, e.g., between electrodes 13a and 13b and between 14a and 14b reduces corrosion damage to the electrodes.

[0215] The AC drive cycle may be implemented by using an interdigitated line configuration combining the top and bottom electrode configuration shown in plan view in figures 6a, 6b, 7a-7f, etc.

[0216] The extent to which transparency or reflectivity is increased or decreased in figures 9b and 9c depends on the voltage and frequencies difference. By varying the voltage difference, the amount by which the transparency or reflectivity increases, respectively, decreases, is controlled. For example, a curve representing light transmission versus voltage may be determined, e.g., measured. To obtain a particular level of light transmission, e.g., a particular transparency, e.g., a particular grayscale level, the corresponding voltage, e.g., AC voltage may be applied. By interpolating the signals for a transparent or for a non-transparent state, levels in between transparent and non-transparent may be obtained. Likewise, a curve representing light reflection versus voltage may be determined, e.g., measured. To obtain a particular level of reflectivity, the corresponding voltage, e.g., AC voltage may be applied. By interpolating the signals for a reflective or for a non-reflective state, levels in between reflective and non-reflective may be obtained.

[0217] Different electrode patterns may be used for a light modulator. The electrode patterns may each provide a range of grayscales, e.g., levels of transparency or reflectivity, that the light modulator can attain. However, the particular range of grayscale for any particular electrode pattern may be different from another electrode pattern. In other words, although different patterns give an increased transparency or reflectivity or an increased opacity, the exact response to a drive signal depends on many factors, including the particular pattern that is used. The variations in the optical properties of a light modulator may have a fine resolution, e.g., below 1 mm. Note that no pixelation of the light modulator is needed to achieve different optical patterns, e.g., logos, visible in the light modulator.

[0218] This effect may be used to embed visible images in the light modulator by locally changing the electrode pattern on the substrates of a light modulator. For example, one may locally have grayscales that have a permanent offset in grayscale relative to each other, because of a different electrode pattern. For example, by locally changing the electrode pattern or its pitch, the maximum transparency or reflectivity can be altered.

[0219] The result is an area on the light modulator which has a different intensity of grayscale, e.g., a different grayscale, or of coloring. The area may have the same color point, though. In an embodiment, they may switch together with the rest of the window, although at a different rate. For example, even if the same voltage is applied to the electrodes in two different areas, they cause a different transparency state, e.g., different transmission level, due to different electrode patterns. For example, a curve representing transmission versus voltage may be shifted. For example, if voltage control is changed in the same way in both areas, then in both areas light transmission may change, but with a different amount. An area may also be made less responsive to a drive signal by reducing the density of electrodes; in particular, an area may be made not to switch at all, e.g., by not applying electrodes in the area.

[0220] For example, the electrode material may be copper, aluminum, gold, indium-tin oxide (ITO), etc. ITO is transparent while Cu / Al is reflective, thus using a different electrode material, a different appearance may be obtained, irrespective of the voltage driving. Likewise, different materials with different resistance will give rise to a different electric field. For example, ITO will have a smaller electric field, even though driven with the same voltage.

[0221] An embodiment of a method of modulating light comprises applying an electric potential to multiple electrodes applied to two opposing substrates according to an embodiment to obtain an electric field between the multiple electrodes providing electrophoretic movement of the particles towards or from one of the multiple electrodes causing modulation of light shining through the substrates, wherein the two opposing substrates are as in an embodiment.

[0222] Various modes of operation are supported by an embodiment of a four-electrode light modulator system.Horizontal drive

[0223] Horizontal drive is a mode in which lateral electric fields are created along the substrate. The light modulator may apply an alternating voltage on the interdigitated electrodes to cause the particles in the optical layer to move parallel to the substrate, thus decreasing transparency.Vertical drive

[0224] Vertical drive is a mode in which particles are aligned orthogonally to the substrates. Electrodes opposite to each other on opposite substrates receive a different voltage.Maintaining a grayscale

[0225] The light modulator drive system may apply 0 voltage on the electrodes most of the time, but if the grayscale is dropping due to the particles dispersing, then briefly the electrodes and may be driven as in vertical drive.

[0226] In all three modes, the driving may use DC or AC signals. Preferably, AC signals are used.

[0227] Figure 10 schematically shows an example of an embodiment of a method 700 for making vacuum insulated glass. Method 700 comprises providing (701) a first substrate, the first substrate having a sealant barrier applied around a perimeter of a surface of the first substrate, providing (702) a second substrate having a surface, applying (703) a sealant on the surface of the first or second substrate, introducing (704) the first and second substrate into a low-pressure chamber, pressing the first and second substrate onto each other, the surfaces of the first and second substrate facing each other, wherein, after the pressing, the sealant has been applied around the perimeter of the surface of the first and second substrate outside the sealant barrier thus sealing a low-pressure layer extending between the first and second substrate, wherein the sealant barrier maintains an integrity of the sealant after the sealant is exposed to atmospheric pressure outside the low-pressure chamber.

[0228] After the low-pressure layer has been established, e.g., using method 700, further layers may be applied, including, a temperature regulating layer and / or a light modulator. These further layers do not necessarily need to use a low-pressure chamber, although this is possible.

[0229] The following clauses represent embodiments.

[0230] Clause 1. A glazing unit, the glazing unit comprising a light modulator, the light modulator comprising a first substrate and a second substrate, the first and second substrates being arranged with inner sides opposite to each other, one or more driving electrodes being applied to the inner side of the first substrate, and an optical layer between the first and second substrates, the one or more driving electrodes being configured to cause modulation of optical properties of the optical layer, a liquid-filled, temperature regulating layer, the temperature regulating layer being arranged against the light modulator, outside of the optical layer, and extending across the surface of the first or second substrate, the temperature regulating layer being arranged for cooling and / or heating of the light modulator.

[0231] Clause 2. The glazing unit of Clause 1, wherein the temperature regulating layer is enclosed between two substrates, the two substrates of the temperature regulating layer having a substrate in common with the light modulator.

[0232] Clause 3. The glazing unit of any one of the preceding clauses, further comprising: a controller operatively connected to the temperature regulating layer, the controller being configured to monitor a temperature of the light modulator and adjust a temperature of the liquid in the temperature regulating layer, the controller being configured to maintain the light modulator temperature within a predetermined temperature range by selectively heating or cooling the liquid in the temperature regulating layer.

[0233] Clause 4. The glazing unit of Clause 3, wherein the controller is further configured to adjust the temperature of the liquid in the temperature regulating layer based on at least one of: ambient temperature, incident solar radiation, and desired optical state of the light modulator.

[0234] Clause 5. The glazing unit of any one of the preceding clauses, wherein the temperature regulating layer is configured to heat the light modulator during optical state transitions of the optical layer, thereby accelerating the transition process.

[0235] Clause 6. The glazing unit of any one of the preceding clauses comprising a low-pressure layer, wherein the low-pressure layer is arranged on a side of the light modulator opposite to the temperature regulating layer, wherein the low-pressure layer extends across the surface of the first or second substrate not in contact with the temperature regulating layer, or the low-pressure layer is arranged on a side of the light modulator adjacent to the temperature regulating layer, wherein the low-pressure layer extends across the surface of the temperature regulating layer.

[0236] Clause 7. The glazing unit of any one of the preceding clauses comprising in order: a first glazing substrate, the light modulator, the temperature regulating layer, the low-pressure layer and a second glazing substrate.

[0237] Clause 8. The glazing unit of Clause 6 or 7, wherein multiple spacers are arranged in the optical layer between the first and second substrates, and multiple spacers are arranged in the low-pressure layer, at least part of the multiple spacers arranged in the optical layer being aligned with at least part of the multiple spacers arranged in the low-pressure layer. Clause 9. The glazing unit of any one of the preceding clauses, wherein multiple spacers are arranged in the optical layer between the first and second substrates, and multiple spacers are arranged in the temperature regulating layer, at least part of the multiple spacers arranged in the optical layer being aligned with at least part of the multiple spacers arranged in the temperature regulating layer.

[0238] Clause 10. The glazing unit according to any one of the preceding clauses, wherein the temperature regulating layer has a refractive index within ±0.03 of the refractive index of the first and / or second substrates, preferable within ±0.02, more preferable ±0.01.

[0239] Clause 11. The glazing unit of any one of the preceding clauses, wherein the liquid in the temperature regulating layer comprises at least one of: a glycol-based compound, and a high thermal conductivity liquid, wherein the high thermal conductivity liquid has a thermal conductivity of at least 0.1 W / (m·K) at 25°C, preferably at least 0.2 W / (m K) at 25°C.

[0240] Clause 12. The glazing unit of any one of the preceding clauses, comprising a frame surrounding at least the light modulator and the temperature regulating layer, wherein a heat sink is integrated within the frame and thermally coupled to the temperature regulating layer, the heat sink being configured to dissipate heat from the temperature regulating layer to the surrounding environment, and / or one or more thermoelectric elements integrated within the frame and thermally coupled to the temperature regulating layer, the one or more thermoelectric elements being configured to harvest heat from the temperature regulating layer and convert the harvested heat into electrical energy.

[0241] Clause 13. The glazing unit of any one of the preceding clauses, wherein the light modulator further comprises an anti-reflective coating applied to the temperature regulating layer.

[0242] Clause 14. The glazing unit of any one of the preceding clauses, further comprising a pump operatively connected to the temperature regulating layer and configured to circulate the liquid within the temperature regulating layer to enhance heat transfer. Clause 15. The glazing unit of any one of the preceding clauses, wherein the unit is integrated into a window frame, wherein the window frame comprises a sunshade arranged to shadow one or more edges of the light modulator from the sun.

[0243] Clause 16. The glazing unit of any one of the preceding clauses, wherein the light modulator has multiple segments, the multiple segments being independently, electrically controllable.

[0244] Clause 17. The glazing unit as in the combination of Clause 15 and Clause 16, wherein at least part of the multiple segments have edges along a side of the window frame, the sunshade being arranged to shadow one or more edges along the side of the window frame.

[0245] Clause 18. The glazing unit of any one of the preceding clauses, wherein the temperature regulating layer comprises channels or microchannels through which the liquid flows.

[0246] Clause 19. The glazing unit of any one of the preceding clauses, wherein the temperature regulating layer comprises a valve to circulate liquid in and out of the glazing unit.

[0247] Clause 20. The glazing unit of any one of the preceding clauses, wherein the optical layer comprises a fluid, e.g., a liquid, that comprises particles, wherein the light modulator is configured to apply an electric potential to the one or more driving electrodes causing modulation of an electric field in the optical layer providing electrophoretic and / or dielectrophoretic movement of the particles in the optical layer causing modulation of light passing through the substrates.

[0248] Clause 21. A glazing unit as in any one of the preceding clauses, wherein a thermoelectric material is distributed between the first substrate and / or the second substrate in the optical layer and / or in a low-pressure layer comprised in the glazing unit, the thermoelectric material being configured to generate electricity from heat.

[0249] Clause 22. A glazing unit as in any one of the preceding clauses, comprising a low-pressure layer, enclosed between a first substrate and a second substrate.

[0250] Clause 23. A glazing unit as in any one of the preceding clauses, comprising a first substrate, the first substrate having a sealant barrier applied around a perimeter of a surface of the first substrate, a second substrate having a surface, the first and second substrate being arranged against each other, with a sealant on the surface of the first and second substrate, the surfaces of the first and second substrate facing each other, wherein the sealant is applied around the perimeter of the surface of the first substrate outside the sealant barrier thus sealing a low-pressure layer extending between the first and second substrate.

[0251] Clause 24. A glazing unit of Clause 23, wherein the sealant barrier determines a cell gap between the first and second substrate, or the sealant barrier cooperates with a further sealant barrier on the second substrate, the sealant barrier and further sealant barrier aligning after the pressing and together determining a cell gap between the first and second substrate.

[0252] Clause 25. A glazing unit as in any one of Clauses 22-24 wherein the low-pressure layer reduces heat conduction across the cell gap between the first and second substrate.

[0253] Clause 26. A glazing unit as in any one of Clauses 22-25, wherein the low-pressure layer has a pressure of at most 1 Pa, or at most 0.1 Pa, or at most 0.05 Pa.

[0254] Clause 27. A glazing unit as in any one of Clauses 23-26, wherein the sealant binds the first and second substrate together.

[0255] Clause 28. A glazing unit as in any one of clauses 22-27, wherein further spacers are arranged between the first and second substrates, e.g., wherein photo spacers are arranged across the surface of the first substrate.

[0256] Clause 29. A glazing unit as in any one of Clauses 22-28, wherein the cell gap is at most 50 mm, or at most 1 mm, or at most 0.5 mm, or at most 0.1 mm, or at most 0.01 mm, and / or the cell gap is at least 1 micron and at most 500 micron, preferably, at least 20 micron and at most 100 micron, preferably, at least 20 micron and at most 50 micron, a sealant barrier width is at least 40% and at most 200% of the cell gap, preferably, at least 75% and at most 125% of the cell gap.

[0257] Clause 30. A glazing unit as in any one of Clauses 22-29, wherein the light modulator is arranged in parallel to the low-pressure layer. The light modulator and low-pressure layer may share a substrate.

[0258] Clause 31. A glazing unit as in any one of preceding clauses, wherein the first substrate and / or the second substrate of the light modulator comprise a photovoltaic system or a display.

[0259] Clause 32. A glazing unit as in any one of Clauses 22-31, comprising a further seal applied around the glazing unit and / or the light modulator, for example, wherein the further seal comprises glass solder, and / or the further seal comprises a thermoplastic adhesive, and / or the further seal is obtained by melting together the substrates of the light modulator and the one or more insulating substrate at their perimeters.

[0260] Clause 33. A glazing unit as in any one of the preceding clauses, wherein at least one driving bus is arranged on a substrate of the light modulator for each driving electrode. For example, at least one driving bus is arranged at a side of the substrate for each driving electrode to drive the driving electrode, and / or the driving busses are only arranged at the side of the substrate, and / or

[0261] Clause 34. A glazing unit as in Clause 33, wherein one or more driving electrodes is isolated from the edges of the substrate, a via being connected to the isolated driving electrode from a surface of the substrate opposite the driving electrode for powering the isolated driving electrode and / or connecting the isolated driving electrode to another part of the driving electrode on the substrate.

[0262] Clause 35. A glazing unit as in any one of the preceding clauses, which is non-rectangular. For example, the substrates of the glazing unit may be non-rectangular.

[0263] Clause 36. A glazing unit as in any one of the preceding clauses, wherein the one or more driving electrodes are multiple driving electrodes, the multiple driving electrodes (111-114,121-124) being interdigitated, each of the multiple driving electrodes being arranged in a pattern across the substrate, the multiple interdigitated driving electrodes being arranged alternatingly with respect to each other on the substrate. For example, the pattern of multiple driving electrodes across the substrate may comprise multiple repeated building blocks. For example, the building block may comprise multiple interdigitated electrodes extending in at least 2 directions across the building block, the interdigitated electrodes in the building block forming the driving electrodes.

[0264] Clause 37. A glazing unit as in any one of the preceding clauses, connected or connectable to a controller configured to apply an electric potential to the one or more driving electrodes causing modulation of the optical properties of the light modulator.

[0265] Clause 38. A glazing unit as in any one of the preceding clauses, wherein at least three electrodes are applied to at least one of the first substrate and the second substrate of the light modulator, or at least three electrodes are applied to both the first substrate and the second substrate of the light modulator.

[0266] Clause 39. A glazing unit as in any one of the preceding clauses, wherein a distance between subsequent main-lines of the one or more driving electrodes in the first substrate is larger than a distance between subsequent main-lines of the one or more driving in the second substrate.

[0267] Clause 40. A glazing unit as in any one of the preceding clauses, wherein the light modulator has a transparent state and a non-transparent state, or having a reflective state and a non-reflective state, the light modulator being configured to switch to the non-transparent state or to the non-reflective state by creating an alternating voltage on at least one of the first and second substrates, applying an alternating current between at least a first electrode and a second electrode on the first substrate and / or between a first electrode and a second electrode on the second substrate, switch to the transparent state or to the reflective state by creating an alternating voltage between the first and second substrate, applying an alternating current between a first electrode on the first substrate and a first electrode on the second substrate, and / or between a second electrode on the first substrate and a second electrode on the second substrate.

[0268] Clause 41. A glazing unit as in any of the preceding clauses, comprising at least one current sensing circuit connected to an electrode of the one or more electrodes on a substrate, the current sensing circuit being configured to measure a current in the electrode to which it is connected; the glazing unit being connected to a controller configured to receive at least one current sensing signal from the at least one current sensing circuit indicating a current in the connected electrode, determine driving signals for the one or more driving electrodes from the at least one current sensing signals and from a target transparency or reflectivity, and apply an electric potential to the one or more driving electrodes according to a driving signal to obtain an electric field between the one or more driving electrodes, wherein the electric field provides electrophoretic movement of the particles towards or from one of the one or more driving electrodes.

[0269] Clause 42. A glazing unit as in Clause 41, wherein the driving signal is provided as an alternating current (AC) in the one or more driving electrodes such that a substantially balanced electrolysis current is obtained.

[0270] Clause 43. A glazing unit as in any one of Clauses 41-42, wherein the driving signal is provided as a direct current (DC) in the one or more driving electrodes, wherein the voltage is periodically reversed to such extent that a substantially balanced electrolysis current is obtained.

[0271] Clause 44. A glazing unit as in any one of Clauses 41-43, comprising multiple current sensing circuits, each electrode being connected to a corresponding one of the multiple current sensing circuits.

[0272] Clause 45. A glazing unit as in any one of Clauses 41-44,wherein the controller is configured to determine a transparency or a reflectivity level of the light modulator from the at least one current sensing signals.

[0273] Clause 46. A glazing unit as in any one of the preceding clauses, wherein the one or more driving electrodes comprise multiple interlaced mesh electrodes extending in a two-dimensional pattern across the first substrate and across the second substrate, two mesh electrodes of the multiple mesh electrodes on a substrate crossing at a plurality of crossing points spread across the substrate.

[0274] Clause 47. A glazing unit as in Clause 46 wherein at least two mesh electrodes on a substrate each comprise multiple main lines extending in a first direction across the substrate, the multiple main lines of the at least two mesh electrodes being arranged alternatingly with respect to each other on the substrate, each of the at least two mesh electrodes comprising multiple interconnecting lines electrically connecting the main lines of said mesh electrode together, multiple main lines of the mesh electrode being connected to other main lines of the mesh electrode through multiple interconnections, an interconnecting line crossing with another mesh electrode forming a crossing point.

[0275] Clause 48. A glazing unit as in Clause 47, wherein a number of the main lines in the electrode comprise at least two interconnecting lines, wherein said number is at least two, at least 10, at least half of the number of main lines, at least 90% of the main lines, or substantially all main lines, and / or a main line is connected to at least 2, at least 4, at least 8, or at least 16 interconnection lines, and / or a main line is connected to an interconnection within distance of the edge of the substrate, the distance being less than 10% of the length of the main line.

[0276] Clause 49. A glazing unit as in any one of Clause 46-48, wherein one or more of the main lines and / or interconnecting lines are straight, or are wavy.

[0277] Clause 50. A glazing unit as in any one of the preceding clauses, wherein wherein at least a part of the inner surface area of at least one of the first substrate and the second substrate of the light modulator is provided with a protective coating.

[0278] Clause 51. A glazing unit as in Clause 50, wherein the protective coating is applied to substantially the entire surface of the one or more driving electrodes

[0279] Clause 52. A glazing unit as in any one of the preceding clauses, wherein the light modulator is an electrophoretic modulator. For example, configured for switching between a transparent state and a non-transparent state and vice versa.

[0280] Clause 53. A glazing unit as in any one of the preceding clauses, wherein the light modulator comprises a connection for applying an electric field to the one or more electrodes, wherein the applied electric field to the one or more electrodes provides movement of nano- and microparticles from a first electrode to a second electrode and vice versa, wherein the one or more electrodes comprise an electrical conducting material with a resistivity of less than 100 nS2m at 273 K, wherein the glazing unit is connected to a power provider in electrical connection with the at least two electrodes, wherein the power provider is adapted to provide a waveform AC power, wherein at least one of amplitude, frequency, and phase is adaptable.

[0281] Clause 54. A glazing unit as in any one of the preceding clauses, wherein the one or more driving electrodes comprise at least two electrodes forming an interdigitated pattern. For example, wherein the interdigitated pattern is a regular 2-dimensional pattern. For example, each finger of the interdigitated pattern comprising at least one waveform shape. For example, wherein the waveform shape has an amplitude A and a width W, and wherein fingers are at a distance d from one and another.

[0282] Clause 55. A glazing unit as in any one of the preceding clauses, wherein the one or more driving electrodes are in fluidic contact with the fluid

[0283] Clause 56. A glazing unit as in any one of the preceding clauses, wherein the one or more electrodes cover 1-30% of the substrate surface.

[0284] Clause 57. A glazing unit as in any one of the preceding clauses, wherein a power provider is operated at an AC frequency for switching to a transparent state of 10-100 Hz, and / or a power provider is operated at an AC frequency for switching to a non-transparent state of less than 1 Hz, such as 30-500 mHz, and / or wherein, within one switching cycle, the power provider is operated at an AC frequency for switching to a transparent state of 10-100 Hz, in combination with the power provider initially being operated at a positive or negative voltage when switching to a transparent state and in combination with the power provider being finally operated at a negative or positive voltage when switching to a non-transparent state, and / or wherein the power provider is adapted to provide pulses and to refrain from providing pulses during intervals, and / or wherein the power provider is adapted to provide a variation in amplitude of 5-100% of a maximum amplitude, and / or wherein a balanced electrolysis current is obtained by continuously switching the polarity of oppositely charged electrodes on the first and on the second substrates and / or between the first and the second substrates.

[0285] Clause 58. A glazing unit as in any one of the preceding clauses, wherein optical layer comprises a fluid, which is an apolar fluid with a dielectric constant less than 15, such as branched or unbranched C8-C60 alkanes, branched or unbranched C8-C60 alkenes, branched or unbranched C6-C60 alcohols, branched or unbranched C6-C60 alkanols, branched or unbranched C8-C60 ketones, branched or unbranched C8-C60 aldehydes, silicon oils, and combinations thereof, and / or the dynamic viscosity of the fluid is 500 mPa.s or less, preferably 50 mPa.s or less, such as less than 1 mPa.s, and / or the fluid has a relative permittivity εr of less than 100, preferably less than 10, and / or the fluid comprises counter ions for compensating a charge on the particles, and / or the fluid comprises counter ions for compensating a charge on the particles selected form sulfate, chloride, bromide, and / or combinations thereof, and / or the fluid comprises one or more of a surfactant, an emulsifier, a polar compound, and a compound capable of forming a hydrogen bond.

[0286] Clause 59. A glazing unit as in any one of the preceding clauses, wherein a size of the nanoparticles is from 20-1000 nm, and / or the particles are adapted to absorb or reflect light with a wavelength of 10 nm-1 micron, and / or a coating of the particles is made from a conducting material and / or a semiconducting material, and / or the particles comprise a magnetic material.

[0287] Clause 60. A glazing unit as in any one of the preceding clauses, wherein a distance between the substrates is maintained at a distance of less than 500 µm using one or more spacers, and / or the optical modulator is flexible, the substrate comprising a flexible material, e.g., flexible glass or a flexible polymer, and / or the substrates have a thickness of 0.01 mm - 2 mm, preferably 0.025 mm 1 mm, such as 0.05-0.5 mm.

[0288] Clause 61. A glazing unit as in any one of the preceding clauses, comprising a stack of light modulators, wherein a number of light modulators is from 2-10, preferably 3-5, and wherein optionally at least one substrate (13,14) of a first light modulator is the same as a substrate (13,14) of at least one second light modulator.

[0289] Clause 62. A glazing unit as in any one of the preceding clauses comprising multiple areas, the multiple areas being independently addressed and / or optically switchable, and / or a driver circuit for changing the appearance of individual areas by applying differing electric fields to control one or more appearance selected from haze, contrast, warm / cold effect, complementary contrast, simultaneous contrast, saturation, intensity.

[0290] Clause 63. A light modulator system, the light modulator system comprising a light modulator, the light modulator comprising a first substrate and a second substrate, the first and second substrates being arranged with inner sides opposite to each other, one or more driving electrodes being applied to the inner side of the first substrate, and an optical layer between the first and second substrates, the one or more driving electrodes being configured to cause modulation of optical properties of the optical layer, a liquid-filled, temperature regulating layer, the temperature regulating layer being arranged against the light modulator, outside of the optical layer, and extending across the surface of the first or second substrate, the temperature regulating layer being arranged for cooling and / or heating of the light modulator.

[0291] Clause 64. A light modulator system as in any one of the preceding clauses or part thereof.

[0292] Clause 65. The glazing unit of any one of the preceding Clauses, further comprising a matrix of temperature sensors distributed across the glazing unit, the matrix of temperature sensors being configured to monitor the temperature at multiple locations across the glazing unit. For example, temperature sensors may be integrated in one or more of the optical layer, temperature regulating layer, and insulating layer.

[0293] Clause 66. The glazing unit of Clause 65, wherein the temperature sensors are integrated with spacers within the glazing unit.

[0294] Clause 67. The glazing unit of Clause 65 or 66, wherein the controller is operatively connected to the matrix of temperature sensors and is configured to receive multiple temperature sensor values and use these values to control the temperature regulating layer and / or the light modulator.

[0295] Clause 68. The glazing unit of any one of the preceding Clauses, wherein the glazing unit comprises multiple areas, the optical properties of the multiple areas being independently and electrically controllable.

[0296] Clause 69. The glazing unit of the combination of Clause 65 and Clause 68, wherein the controller is configured to use multiple temperature values from the matrix of temperature sensors to control the optical properties of the multiple areas independently.

[0297] Clause 70. The glazing unit of any one of Clauses 65-69, wherein the controller is configured to use data from the matrix of temperature sensors to detect daily cycles in temperature across the glazing unit and to anticipate these cycles in controlling the temperature regulating layer.

[0298] Clause 71. The glazing unit of any one of the preceding Clauses, comprising a backup energy storage, wherein the controller is configured to initiate cooling via the temperature regulating layer if the temperature detected by the matrix of temperature sensors exceeds a predetermined limit, using energy from the backup energy storage. For example, the backup energy storage may be charged through a thermoelectric element, a photovoltaic element, etc. the backup energy storage may be charged through the electrical grid.

[0299] Clause 72. The glazing unit of any of the preceding Clauses, wherein heating electrodes are arranged on a surface of a substrate of the light modulator system, in particular on a surface facing the temperature regulating layer, and / or a surface facing the optical layer. Heating the glazing unit, e.g., the temperature regulating layer, and / or the optical layer may comprise conducting a current through the heating electrodes. The heating electrodes may form a loop, allowing current to enter and leave the heating electrodes.

[0300] It should be noted that the above-mentioned embodiments illustrate rather than limit the presently disclosed subject matter, and that those skilled in the art will be able to design many alternative embodiments.

[0301] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb 'comprise' and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements. Expressions such as "at least one of' when preceding a list of elements represent a selection of all or of any subset of elements from the list. For example, the expression, "at least one of A, B, and C" should be understood as including only A, only B, only C, both A and B, both A and C, both B and C, or all of A, B, and C. The presently disclosed subject matter may be implemented by hardware comprising several distinct elements, and by a suitably programmed computer. In the device claim enumerating several parts, several of these parts may be embodied by one and 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 advantage.

[0302] In the claims references in parentheses refer to reference signs in drawings of exemplifying embodiments or to formulas of embodiments, thus increasing the intelligibility of the claim. These references shall not be construed as limiting the claim.

Examples

Embodiment Construction

[0011]While the presently disclosed subject matter is susceptible of embodiment in many different forms, there are shown in the drawings and will herein be described in detail one or more specific embodiments, with the understanding that the present disclosure is to be considered as exemplary of the principles of the presently disclosed subject matter and not intended to limit it to the specific embodiments shown and described.

[0012]In the following, for the sake of understanding, elements of embodiments are described in operation. However, it will be apparent that the respective elements are arranged to perform the functions being described as performed by them.

[0013]Further, the subject matter that is presently disclosed is not limited to the embodiments only, but also includes every other combination of features described herein or recited in mutually different dependent claims.

[0014]Figure 1a schematically shows an example of an embodiment of a light modulator system 100 compris...

TECHNICAL FIELD

[0001] The presently disclosed subject matter relates to a glazing unit.BACKGROUND

[0002] A known glazing unit is described in the article "Vacuum glazing: Current performance and future prospects," by Philip C. Eames. The known glazing unit comprises an insulating layer, in this case a low-pressure layer. The article explains that vacuum glazing is similar to double glazing in which the gas-filled space is evacuated to low pressure, thus reducing the levels of convection and gaseous conduction to negligible values.

[0003] The known vacuum glazing is assembled from two glass sheets, cut to the required dimensions. In one of the sheets an evacuation tube is installed, which is attached during manufacture to an evacuation system. After evacuation, the evacuation tube is sealed.

[0004] The known glazing units have several shortcomings. In particular, when used in a building facade, the known glazing cannot adjust for incoming solar radiation.SUMMARY

[0005] It would be advantageous to have an improved glazing unit. A glazing unit is described that comprises a light modulator, and a liquid-filled, temperature regulating layer.

[0006] The light modulator may comprise a first substrate and a second substrate, the first and second substrates being arranged with inner sides opposite to each other, one or more driving electrodes being applied to the inner side of the first substrate, and an optical layer between the first and second substrates, the one or more driving electrodes being configured to cause modulation of optical properties of the optical layer.

[0007] The temperature regulating layer may be arranged against the light modulator, outside of the optical layer, and extending across a surface of the light modulator. The temperature regulating layer may be arranged for cooling and / or for heating of the light modulator.

[0008] In an embodiment, the glazing unit comprises an insulating layer. The insulating layer is preferably a low-pressure layer.BRIEF DESCRIPTION OF DRAWINGS

[0009] Further details, aspects, and embodiments will be described, by way of example only, with reference to the drawings. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. In the figures, elements which correspond to elements already described may have the same reference numerals. In the drawings, Figure 1a schematically shows an example of an embodiment of light modulator with temperature regulating layer, Figure 1b schematically shows an example of an embodiment of light modulator with temperature regulating layer, Figure 1c schematically shows an example of an embodiment of light modulator with temperature regulating layer, Figure 1d schematically shows an example of an embodiment of light modulator with temperature regulating layer, Figure 1e schematically shows an example of an embodiment of light modulator with temperature regulating layer, Figure 2a schematically shows an example of an embodiment of a glazing unit, Figure 2b schematically shows an example of an embodiment of a glazing unit, Figure 3 schematically shows an example of an embodiment of a glazing unit, Figure 4 schematically shows an example of an embodiment of a glazing unit, Figure 5 schematically shows an example of an embodiment of method of manufacturing a light modulator system and / or a glazing unit. Figure 6a schematically shows an example of an embodiment of a building block, Figure 6b schematically shows an example of an embodiment of a substrate, Figures 7a-7f schematically show an example of an embodiment of a substrate, Figure 8a schematically shows an example of an embodiment of a light modulator, Figure 8b schematically shows an example of an embodiment of a light modulator, Figure 8c schematically shows an example of an embodiment of a car, Figures 9a-9c schematically show an embodiment of a light modulator, Figure 10 schematically shows an example of an embodiment of a method for making vacuum insulated glass, Reference signs list

[0010] The following list of references and abbreviations corresponds to the figures, and is provided for facilitating the interpretation of the drawings and shall not be construed as limiting the claims. 100-104a light modulator with liquid cooling 110a light modulator 111a first substrate 112a second substrate 113one or more driving electrodes 114an optical layer 121a first glazing substrate 122a second glazing substrate 130temperature regulating layer 131a first substrate 132a second substrate 140an insulating layer, e.g., a low pressure layer 151an optical layer spacer 152an insulating layer spacer, e.g., a low pressure layer spacer 153a temperature regulating layer spacer 160a controller 161a temperature sensor 162an outside sensor 163an inside sensor 170a thermoelectric element 171a heat sink 172liquid exchange mechanism 173a frame 191an outside side 192an inside side 200-201a glazing unit 300a glazing unit 400a glazing unit 401a sunshade 410a pivot 600a substrate 611-614a main line 621-624a main line 631-634interdigitated electrodes 640a building block 641-644a building block 610, 620a driving bus 619, 629a connecting zone 691, 692a direction 10a light modulator 11a first substrate 12a second substrate 13, 13a, 13belectrodes 14, 14a, 14belectrodes 15a fluid 16a controller 18a spacer 30particles 20a car 21a light modulator 40a light modulator 41a first substrate 42a second substrate 43a third substrate 46a controller DESCRIPTION OF EMBODIMENTS

[0011] While the presently disclosed subject matter is susceptible of embodiment in many different forms, there are shown in the drawings and will herein be described in detail one or more specific embodiments, with the understanding that the present disclosure is to be considered as exemplary of the principles of the presently disclosed subject matter and not intended to limit it to the specific embodiments shown and described.

[0012] In the following, for the sake of understanding, elements of embodiments are described in operation. However, it will be apparent that the respective elements are arranged to perform the functions being described as performed by them.

[0013] Further, the subject matter that is presently disclosed is not limited to the embodiments only, but also includes every other combination of features described herein or recited in mutually different dependent claims.

[0014] Figure 1a schematically shows an example of an embodiment of a light modulator system 100 comprising a temperature regulating layer 130 and a light modulator 110.

[0015] The light modulator is suitable for integration into a glazing unit, e.g., by combining the light modulator with a temperature insulating layer. Such integration is advantageous but not necessary. For example, the temperature insulating layer may be a low-pressure layer. For example, the temperature insulating layer may be another type of insulating layer, e.g., as used in double glazing, such as a gas-filled layer, e.g., filled with argon and / or krypton, which provides improved thermal insulation by reducing heat transfer. The temperature insulating layer has lower thermal conductivity compared to air, thereby enhancing the overall energy efficiency of the glazing unit.

[0016] Light modulator system 100 may be any light modulator, e.g., as described herein. In particular, the light modulator system 100 comprises an optical layer. The optical properties of the optical layer may be modulated electrically, e.g., by one or more driving electrodes arranged in or near the optical layer. For example, the driving electrodes may be arranged to modulate an electric field inside the optical layer, causing modulation of the optical properties. Light passing through the light modulator will be affected by the optical layer and its optical properties as configured electrically, e.g., through the one or more driving electrodes.

[0017] Typically, the optical state of the light modulator can be varied between more transparent and less transparent states. Often, grayscale control between these two states is possible. There are various other optical properties for which the light modulator could be configured, e.g., more or less reflective states.

[0018] In an embodiment, the light modulator has multiple segments that are independently and electrically controllable, meaning they have independently and electrically controllable optical properties. For example, one segment may have different transparency or reflectivity compared to another segment.

[0019] A liquid-filled temperature regulating layer is arranged next to the light modulator. The temperature regulating layer is positioned against the light modulator outside of the optical layer and extends across a surface of light modulator 110.

[0020] Both the optical layer and the temperature regulating layer are each arranged between two substrates, one of which may be shared between the two layers. The substrates are typically transparent.

[0021] The temperature regulating layer may be arranged for cooling the light modulator. Heat may build up in the light modulator, e.g., due to transitions between different optical states of the light modulator or from sunlight impinging on the light modulator. Especially if the light modulator is in a less transparent state, e.g., a more opaque state, the energy from sunlight may increase heat inside the light modulator. Excessive heat, especially if prolonged, can have detrimental effects, e.g., reduced lifespan of the optical modulator. For example, the temperature regulating layer may be configured to transfer heat away from the light modulator.

[0022] Furthermore, the temperature regulating layer may be used to increase the temperature of the light modulator. Typically, a light modulator does not function well if its temperature is too low. The temperature regulating layer may be configured to transfer heat to the light modulator, in particular its optical layer, for improved functioning. For example, a light modulator placed in a region with low ambient temperatures is beneficially heated to improve functioning.

[0023] In a further advantageous embodiment, the temperature regulating layer selectively lowers and / or increases the temperature. Transitions in the optical layer, e.g., for a particle-based optical layer, proceed faster at a higher temperature. Especially diffusion of particles, e.g., as needed for decreasing transparency, proceeds faster at higher temperatures. Accordingly, the temperature regulating layer may be configured to increase the temperature in the optical layer, e.g., by transferring heat towards it or by cooling it less before and / or during an optical state transition, in particular a transition to a less transparent state.

[0024] Preferably, the refractive index of the temperature regulating layer is tuned to the refractive index of the light modulator, e.g., of the substrates enclosing the light modulator. For example, the temperature regulating layer may have a refractive index within ±0.03 of the refractive index of the light modulator, e.g., its substrates, preferably within ±0.02, more preferably ±0.01.

[0025] The temperature regulating layer is filled with a liquid, preferably a liquid with high thermal conductivity. For example, the liquid may have a thermal conductivity of at least 0.1 W / (m K) at 25°C, preferably at least 0.2 W / (m K) at 25°C. For example, the liquid may comprise a glycol-based compound.

[0026] Reference is made to European patent applications EP24177302.7 and EP24194098.0, which describe vacuum-insulated glass and methods for making vacuum-insulated glass. The vacuum-insulated glass method can be used to prepare a heat-regulating window by replacing the vacuum between the substrates with a high heat conductive liquid.

[0027] There are several ways to use a temperature regulating layer. In a first example, the temperature regulating layer is passive. Heat from the light modulator is absorbed in the temperature regulating layer, where it diffuses. When the light modulator is in a state that does not produce heat, the light modulator and temperature regulating layer will both dissipate heat to the environment. In this way, heat regulation takes place while no external communication between the temperature regulating layer and the environment is needed. Additionally, the temperature regulating layer diffuses local heat generated on the window. For example, when the sun is shining partially on a window, surface temperature difference of the glass may create cracks and defects due to strong temperature change in short distances. By reducing temperature difference across the glazing unit, the temperature regulating layer may limit or even eliminate such effects.

[0028] A second example is shown in Figure 1b. Figure 1b schematically shows an example of an embodiment of light modulator system 101 comprising a temperature regulating layer 130 and a light modulator 110.

[0029] In a second example, the temperature regulating layer is also sealed without liquid exchange. However, the temperature regulating layer is in contact with a heat sink 171. For example, the heat sink 171 may be in contact around the perimeter of the light modulator and temperature regulating layer. The heat sink 171 may also contact the perimeter of the light modulator. For example, the heat sink 171 may be integrated into a frame, e.g., a frame of a glazing unit.

[0030] Heat from the light modulator is absorbed in the temperature regulating layer, where it diffuses. The temperature regulating layer is connected to the heat sink, which will also absorb the heat. The heat sink may further release heat to the environment.

[0031] The heat sink is typically used to extract heat from the system but could also be used to heat the temperature regulating layer if needed; for example, to increase temperature before or during optical transitions.

[0032] Heat sink 171 is a passive component that dissipates heat in the temperature regulating layer, e.g., generated by the light modulator or absorbed from the sun into the surrounding environment. The heat sink comprises a material with high thermal conductivity, such as metal, e.g., aluminum or copper, to transfer heat away from the device.

[0033] The heat sink may have surface elements that increase the surface area for heat dissipation through convection, e.g., fins and / or ridges.

[0034] The heat sink may be combined with active cooling to enhance cooling efficiency, e.g., air-cooling, e.g., fans; liquid-cooling. For example, the active cooling may cool the heat sink and / or surface elements. Alternatively, active heating may heat the heat sink and / or surface elements. Active heating may use instead or in addition, an integrated heating element, e.g., heating electrodes arranged on a surface of a substrate of the light modulator system, in particular on a surface facing the temperature regulating layer, and / or a surface facing the optical layer.

[0035] In a third example, the temperature regulating layer exchanges liquid with the environment. Figure 1c schematically shows an example of an embodiment of light modulator system 102 comprising a temperature regulating layer 130 and a light modulator 110. The temperature regulating layer is connected to a liquid exchange mechanism 172. In this embodiment, the temperature regulating layer is not only responsible for absorbing and diffusing heat from the light modulator but also actively engages in heat exchange with the environment through a liquid exchange mechanism 172.

[0036] The temperature regulating layer is connected to a liquid exchange mechanism 172, which allows for the flow of liquid into and out of the temperature regulating layer. This setup allows quick, precise, and dynamic regulation of the temperature within the layer by directly exchanging heated liquid with cooler liquid from the environment or vice versa, depending on the thermal requirements of the system.

[0037] For example, liquid exchange mechanism 172 may comprise a valve, e.g., multiple valves. The valve can control the circulation of liquid. For example, a first valve may allow liquid to flow into the temperature regulating layer, while a second valve may control liquid flowing out of the temperature regulating layer. There may be multiple first valves and multiple second valves. The valves are convenient but optional. For example, the valves make connecting and disconnecting to a pump more convenient.

[0038] A pump may be operatively connected to the temperature regulating layer through liquid exchange mechanism 172, e.g., connecting to said valves. The pump is configured to circulate the liquid within the temperature regulating layer, enhancing the heat transfer process. By actively circulating the liquid, the system can more effectively dissipate heat from the light modulator. For example, when the liquid is outside of the temperature regulating layer, it can be actively heated or cooled as desired. This allows for quick and precise modulation of the temperature in the temperature regulating layer and, from there, in the light modulator.

[0039] The temperature regulating layer may form a chamber for the liquid from which liquid exchange is done through mechanism 172. In an embodiment, the temperature regulating layer includes channels or microchannels through which the liquid flows. These channels facilitate efficient heat transfer by maximizing the surface area contact between the liquid and the material of the temperature regulating layer.

[0040] One application of the temperature regulating layer is to cool the light modulator. Another application of the temperature regulating layer is to heat the light modulator, especially before or during optical transitions, most especially for a transition to a more opaque state, e.g., wherein particles in the optical layer disperse. Accordingly, the temperature regulating layer may be configured to heat the light modulator. After the transition is complete, the temperature regulating layer may cool the light modulator. This helps maintain the stability of the light modulator, e.g., the time during which the light modulator's optical state is stable without actively electrically controlling the light modulator.

[0041] For example, a controller may be operatively connected to the temperature regulating layer. The controller is configured to monitor the temperature of the light modulator and adjust the temperature of the liquid in the temperature regulating layer. The temperature of the light modulator may be measured directly, e.g., through a sensor integrated with the light modulator. The light modulator temperature may also be obtained from a virtual sensor, e.g., a temperature estimate obtained from a model that takes as input various other measurements, e.g., that may be easier to obtain, e.g., one or more of: ambient temperature outside, ambient temperature inside, solar irradiance, solar hours, previous use of the light modulator, etc. For example, the model could be a neural network; even a small neural network will work.

[0042] The liquid in the temperature regulating layer may be heated by environmental conditions, external sources of heat, and / or directly by an heating system integrated in the glazing unit, e.g., on a substrate, such as a substrate of the temperature regulating layer. For example, integrated heating may be done by current passing through electrodes on a surface of the substrate; for example, the heating electrodes may be arranged across a surface of the temperature regulating layer. Heating may also be performed by passing a current through driving electrodes of the light modulator. In the latter case the temperature regulating layer help diffusing the additional heat.

[0043] The controller is configured to maintain the light modulator temperature within a predetermined temperature range by selectively heating or cooling the liquid in the temperature regulating layer. For example, one of the embodiments of Figures 1b and 1c may be used for active temperature control of the temperature regulating layer. The predetermined temperature may depend on the intended use of the light modulator. For example, if the light modulator is about to or is undergoing an optical state transition, a higher temperature may be maintained than when the light modulator is stable.

[0044] In an embodiment, the light modulator comprises an anti-reflective coating, e.g., applied to the temperature regulating layer.

[0045] Figure 1d schematically shows an example of an embodiment of light modulator system 103 comprising a temperature regulating layer 130 and a light modulator 110.

[0046] Light modulator 110 comprises a first substrate 111 and a second substrate 112. The first and second substrates are arranged with their inner sides opposite to each other. An optical layer 114 is arranged between the first and second substrates. In this example, light modulator optical layer 114 comprises a fluid, e.g., a liquid that comprises particles.

[0047] One or more driving electrodes 113 are applied on the inner side of first substrate 111 and the inner side of second substrate 112. The light modulator is configured to apply an electric potential to the one or more driving electrodes, causing modulation of an electric field in the optical layer. This, in turn, causes electrophoretic and / or dielectrophoretic movement of the particles in the optical layer, leading to modulation of light passing through the substrates.

[0048] In the example shown two electrodes applied on substrate 111: electrodes 113.1 and 113.2 The two electrodes may each contain multiple electrode lines, e.g., main lines, or fingers, and alternate on the substrate. In the example shown two electrodes applied on substrate 112: electrodes 113.3 and 113.4 The two electrodes may each contain multiple electrode lines, e.g., main lines, or fingers, and alternate on the substrate. A four electrode design, with at least two electrodes per substrate is advantageous, but designs with various numbers of electrodes are possible.

[0049] Next to light modulator 110, a temperature regulating layer 130 is arranged. Temperature regulating layer 130 is enclosed between two substrates. Shown are first substrate 131 and second substrate 132, between which extends temperature regulating layer 130. As shown, first substrate 131 is adjacent to second substrate 112.

[0050] Using two substrates for temperature regulating layer 130 is convenient as it allows for the manufacture of the temperature regulating layer separately from the light modulator.

[0051] Also shown in light modulator system 103 are optical layer spacers 151. Depending on the area and thickness of the optical layer 114 and the thickness of substrates 111 and 112, optical layer spacers 151 may be included in the design to keep the light modulator flat. Although not shown in Figure 1d, spacers may also be included in the temperature regulating layer.

[0052] For example, spacers may be applied onto substrates 131, 132, 112, and / or 111 by various processes, e.g., using photolithography, before assembling the light modulator system. Spacers may be included in each of the layers shown herein.

[0053] In an embodiment, multiple spacers are arranged in the optical layer as well as in the temperature regulating layer. In an embodiment, at least part of the multiple spacers arranged in the optical layer may be aligned with at least part of the multiple spacers arranged in the temperature regulating layer. This arrangement increases the mechanical integrity of the light modulator system. In fact, all of the optical layer spacers may align with a temperature layer spacer, although this is not necessary.

[0054] The light modulator system may be further mechanically protected by an insulating layer, such as a low-pressure layer, and glazing substrates.

[0055] The light modulator system temperature may be homogenized and / or kept at a desired level by heating or cooling the temperature regulating layer.

[0056] A thermoelectric material may be included between first substrate 111 and second substrate 112 in the optical layer. The thermoelectric material is configured to generate electricity from heat.

[0057] Figure 1e schematically shows an example of an embodiment of light modulator system 104 with a temperature regulating layer.

[0058] Light modulator system 104 comprises a light modulator 110. Light modulator 110 comprises an optical layer 114 enclosed between a first substrate 111 and a second substrate 112. Light modulator system 104 comprises a temperature regulating layer 130 enclosed between two substrates. The two substrates of the temperature regulating layer have a substrate in common with the light modulator.

[0059] In this case, the optical layer is enclosed between substrates 111 and 112. The temperature regulating layer 130 is enclosed between substrates 112 and 132. Thus, one less substrate can be used. This reduces costs and increases the effectiveness of the temperature regulating layer 130. This arrangement can be manufactured, for example, by stacking the substrates as could be done in an LCD machine.

[0060] Shown in Figure 1e is a temperature sensor 161 integrated into the temperature regulating layer. Alternatively, or in addition, temperature sensor 161 may be integrated into the optical layer itself. Communication with sensor 161 may be through electrode lines on the substrate on which the sensor is applied, in this example, on substrate 112.

[0061] Having only one substrate between the temperature regulating layer increases the accuracy of sensor 161. Sensor 161 may be integrated into the other light modulator systems shown herein and in glazing units as well.

[0062] Figure 2a schematically shows an example of an embodiment of a glazing unit 200.

[0063] Glazing unit 200 comprises a light modulator system, including a light modulator 110 and a temperature regulating layer 130. For example, the light modulator system may be as shown with respect to Figures 1a-1e. Glazing unit 200 comprises an insulating layer 140, preferably a low-pressure layer.

[0064] In the example shown, temperature regulating layer 130 is arranged between light modulator 110 and insulating layer 140. Insulating layer 140 is arranged on a side of light modulator 110 adjacent to temperature regulating layer 130, wherein the low-pressure layer extends across the surface of temperature regulating layer 130.

[0065] The glazing unit itself is enclosed between a first glazing substrate 121 and a second glazing substrate 122.

[0066] For example, glazing unit 200 may comprise, in order: a first glazing substrate 121, a light modulator 110, a temperature regulating layer 130, an insulating layer 140, e.g., a low-pressure layer, and a second glazing substrate 122. Although not separately shown in Figure 2a, there may be additional substrates. For example, there may be a substrate between light modulator 110 and first glazing substrate 121. Similarly, there may be a substrate between insulating layer 140 and second glazing substrate 122.

[0067] In an embodiment of a glazing unit organized according to Figure 2b that has spacers in insulating layer 140 as well as in regulating layer 130, it is beneficial not to align these spacers with each other, to avoid creating a conduit for transmitting heat.

[0068] Figure 2b schematically shows an example of an embodiment of a glazing unit 201. Figure 2b differs from Figure 2a in an alternative arrangement of temperature regulating layer 130. In the example shown, light modulator 110 is between temperature regulating layer 130 and insulating layer 140. Insulating layer 140, e.g., a low-pressure layer, is arranged on a side of light modulator 110 opposite to temperature regulating layer 130. Insulating layer 140 extends across a surface of a substrate of light modulator 110 which is not in contact with temperature regulating layer 130.

[0069] The glazing unit itself is enclosed between a first glazing substrate 121 and a second glazing substrate 122.

[0070] For example, glazing unit 201 may comprise, in order: a first glazing substrate 121, a temperature regulating layer 130, a light modulator 110, an insulating layer 140, e.g., a low-pressure layer, and a second glazing substrate 122. Although not separately shown in Figure 2b, there may be additional substrates. For example, there may be a substrate between temperature regulating layer 130 and first glazing substrate 121. For example, there may be a substrate between insulating layer 140 and second glazing substrate 122.

[0071] Note that light modulator 110 may share a substrate with temperature regulating layer 130, e.g., as shown in Figure 1e, and may share a substrate with insulating layer 140. Such sharing of substrates is also possible in Figure 2a, between light modulator 110 and temperature regulating layer 130, and between temperature regulating layer 130 and insulating layer 140.

[0072] Preferably, insulating layer 140 is a low-pressure layer, also known as vacuum insulated glass (VIG). In an embodiment, the low-pressure layer has a pressure of at most 1 Pa, or at most 0.1 Pa, or at most 0.05 Pa.

[0073] The low-pressure layer reduces heat conduction across the cell gap between its enclosing substrates. By sealing a low-pressure layer between two substrates a thermal barrier is created that reduces heat conduction between the substrates. Vacuum insulated glass is useful in applications requiring thermal insulation, such as in energy-efficient windows for buildings and temperature-controlled environments in vehicles, e.g., cars.

[0074] In an embodiment of a glazing unit organized according to Figure 2b that has spacers in insulating layer 140 as well as in light modulator 110, it is beneficial not to align these spacers with each other, to avoid creating a conduit for transmitting heat.

[0075] Either option shown in Figures 2a and 2b provides heat management for light modulator 110. However, placing temperature regulating layer 130 between light modulator 110 and insulating layer 140 can be slightly more advantageous, since heat dissipation between light modulator 110 and insulating layer 140 will likely be worse than that of dissipation between light modulator 110 and glazing substrate 121.

[0076] In embodiments according to figures 2a or 2b, the temperature regulating layer has the further effect of reducing temperature difference across the glazing unit. In figure 2b, this effect is particularly advantageous, since temperature regulating layer 130 is next to glazing substrate 121, which is arranged to face to the outside, e.g., to the sun. Temperature regulating layer 130 is not only effective in regulating light modulator 110, but also glazing substrate 121. For example, glazing substrate 121, and possibly also glazing substrate 122 may be laminated glass. Laminated glass is particular vulnerable to temperature differences and benefits particularly from temperature regulating layer 130.

[0077] For example, laminated glass comprises multiple layers of glass, possibly with an interlayer, e.g., a plastic interlayer, e.g., a synthetic resin, specifically a thermoplastic, e.g., polyvinyl butyral (PVB). The interlayer may be sandwiched between glass layers.

[0078] Figure 3 schematically shows an example of an embodiment of a glazing unit 300.

[0079] Glazing unit 300 comprises a light modulator 110, a temperature regulating layer 130, and an insulating layer 140. Glazing unit 300 follows the organization of Figure 2a, but could be changed to that of Figure 2b. If glazing unit 300 is employed in the facade of a building, then 191 may denote the outside part, e.g., the part facing the sun, and 192 facing the inside, e.g., a room, an office, or the like.

[0080] Glazing unit 300 comprises, in order: - - a glazing substrate 121 - - a light modulator 110; light modulator 110 may be according to a light modulator as shown herein, possibly the light modulator of Figure 1d. The optical layer 114 of light modulator 110 may comprise spacers. - - a temperature regulating layer 130. Note that temperature regulating layer 130 is enclosed by its own substrates 131 and 132 in this example. However, either one of substrates 131 or 132, or both, could be removed from the design. Temperature regulating layer 130 also contains an optional sensor. As shown, temperature regulating layer 130 is connected to a heat sink 171. Heat sink 171 is optional or could be replaced by liquid exchange mechanism 172. - - an insulating layer 140. Insulating layer 140 is preferably a low-pressure layer. In the example shown, insulating layer 140 comprises spacers. Insulating layer 140 also comprises an optional thermoelectric element 170. Note that there is only one substrate shown between temperature regulating layer 130 and insulating layer 140. For example, this could be achieved by manufacturing these two layers together. Alternatively, an additional substrate may be included between these layers. - a glazing substrate 122

[0081] Optionally, a substrate may be introduced between glazing substrate 122 and the insulating layer. In this way it can be avoided that the glazing substrates are introduced into a low-pressure chamber. Typically, glazing substrate 121 and 122 provide mechanical stability to the glazing unit; for example, glazing substrate 121 and / or 122 may be thicker than substrates 111, 112, 131, and 132. Note that one of substrates 112 and 131 may be omitted. Also a substrate may be introduced between substrate 132 and the insulating layer 140.

[0082] Glazing unit 300 may comprise a frame 173 surrounding at least light modulator 110 and temperature regulating layer 130, and preferably insulating layer 140. Part of the frame is shown. Heat sink 171 may be integrated within the frame and thermally coupled to temperature regulating layer 130. Heat sink 171 may be configured to dissipate heat from temperature regulating layer 130 to the surrounding environment.

[0083] Optionally, one or more thermoelectric elements may be integrated within the frame and thermally coupled to temperature regulating layer 130. The thermoelectric elements are configured to harvest heat from temperature regulating layer 130 and convert the harvested heat into electrical energy.

[0084] In this embodiment, optical layer 114, temperature regulating layer 130, and insulating layer 140 may each contain spacers. Spacers are shown in optical layer 114 and insulating layer 140.

[0085] The multiple spacers arranged in the optical layer between the first and second substrates, and the multiple spacers arranged in insulating layer 140, are aligned, at least in part.

[0086] If spacers are included in temperature regulating layer 130, then it is beneficial to avoid aligning them with the spacers in insulating layer 140. Figure 3a shows a temperature regulating layer spacer 153, although there could be multiple. Note that temperature regulating layer spacer 153 is not aligned with insulating layer spacers 152.

[0087] In Figure 3a, a thermoelectric material is included between substrates 132 and 122. The thermoelectric material is configured to generate electricity from heat.

[0088] For both insulating layer 140 and temperature regulating layer 130, the spacers can be aligned with respect to some of the spacers of light modulator 110.

[0089] Light modulator 110, temperature regulating layer 130, and insulating layer 140 are mechanically protected by the glazing substrates.

[0090] Glazing unit 300 includes or may be associated with an outside sensor 162. For example, sensor 162 may measure, e.g., incident solar radiation or ambient temperature. Glazing unit 300 may include a temperature sensor 161, and an inside sensor 163. Inside sensor 163 may, for example, be located in an office or room or the like. Inside sensor 163 may be a temperature sensor. A controller 160, which may be operatively coupled to glazing unit 300, may receive input from any one of sensors 161, 162, 163. Controller 160 may further receive information on the state of light modulator 110, e.g., by measuring a current between driving electrodes in light modulator 110. Controller 160 may further have information regarding a current optical state of light modulator 110 and a desired state of light modulator 110.

[0091] Controller 160 receives information regarding the state of the glazing unit, e.g., one or more of the information described above, and may use this information to compute, or look up, an operating temperature for light modulator 110, and modulate temperature regulating layer 130 to reach the operating temperature.

[0092] For example, before and / or during an optical transition, the operating temperature may be increased; after the optical transition is complete, the operating temperature may be decreased.

[0093] In an embodiment, glazing unit 300 may comprise a matrix of temperature sensors distributed across glazing unit 300. The temperature sensor matrix comprises multiple sensors. The matrix is configured to monitor the temperature at multiple locations across the glazing unit, preferably in or close to the light modulator. For example, the matrix may be incorporated in the optical layer, the temperature regulating layer, and / or the insulating layer. In an embodiment, a temperature sensor, and in particular, the temperature sensor may be combined with spacers. The integration of these sensors within the glazing unit's structure, including possible integration with spacers, enables precise temperature management across the glazing system. This is important as there may be significant temperature differences across the glazing unit, e.g., because it may be partially shaded.

[0094] There are various ways to combine a temperature sensor with a spacer, e.g., inside an optical layer, or any of the other layers. The spacer could be a photo spacer, e.g., created using photolithography, or other deposition processes. The spacer is preferably transparent. The temperature may be a thin-film temperature sensor which may be embedded directly into or onto the body of the spacer. For example, the sensor could be a resistive temperature detector (RTD), thermistor, or a miniature thermocouple. The temperature sensor can be placed at the center or along the edges of the space. Positioning it at the center would ensure it measures the temperature of the spacer material itself, which will be in thermal contact with the surrounding medium in the optical layer. For additional data on temperature, temperature sensor could be positioned at a variety of locations, e.g., at an edge and / or at the center of a spacer; temperature sensors could be included in multiple layers. The latter provided data on heat conduction within the glazing unit. For example, if the spacer acts as a thermal bridge between two substrates, the sensor may provide real-time data on temperature gradients across the optical layer.

[0095] Conductive traces may be integrated into the spacer design, from where they connect to a controller. Conductive transparent oxides (such as ITO) could be used for wiring if transparency is critical. The embedded sensors could be connected to the controller via micro-wires or through wireless communication from the glazing unit to the controller.

[0096] The sensor may be powered by the same circuitry driving the light modulator, or by harvesting energy from ambient light or thermal differences.

[0097] The temperature data collected by the sensor matrix is transmitted to controller 160, which is operatively connected to the sensors. The controller receives multiple temperature readings and utilizes this information to adjust the temperature regulating layer and / or the light modulator. For instance, by dynamically controlling the temperature regulating layer, the controller can prevent localized overheating or undercooling, thus preserving the structural and optical integrity of the glazing unit.

[0098] In an embodiment, glazing unit 300 comprises multiple areas with independently controllable optical properties, also referred to as segments. The controller uses the temperature data from the sensor matrix to independently adjust the optical states of these areas. This capability is advantageous for example, where varying sunlight exposure or internal temperatures require differential treatment across the glazing unit.

[0099] Alternatively, or in addition, the temperature regulating layer comprises multiple areas with are independently temperature controllable. The controller uses the temperature data from the sensor matrix to independently adjust the cooling and / or heating of these areas.

[0100] The controller may be programmed to detect daily temperature cycles and anticipate these variations in its control algorithms. By predicting temperature changes based on historical data and / or current sensor readings, the system can preemptively adjust the temperature regulating layer to maintain consistent temperature.

[0101] In an embodiment, glazing unit 300 comprises a backup energy storage. The glazing unit may be configured to initiate cooling via the temperature regulating layer if the matrix of temperature sensors detects that the temperature exceeds a predetermined limit using the backup energy storage for power if needed. The backup energy storage may be charged through various means, including thermoelectric elements, photovoltaic elements, or the electrical grid. This feature protects the light modulator and the overall system from potential damage due to overheating, even in case of power shortages. The substrates used in a glazing unit and / or light modulator are typically transparent. For example, the substrates may be made from glass and / or plastic. Although, for a light modulator system, one or more of the substrate may be non-transparent, e.g., in an electrically controllable mirror, etc.

[0102] Glazing substrate 121 and / or Glazing substrate 122 may be made of glass. Various types of glass are possible, e.g., float glass, tempered glass, laminated glass, etc. Glazing substrate 121 and / or Glazing substrate 122 may be made of plastic, e.g., polycarbonate, acrylic, ETFE, etc.

[0103] The embodiment shown is double glazing, e.g., having two glazing substrates which enclose an insulating layer, e.g., insulating layer 140. In an embodiment, single glazing could be make, e.g., by omitting glazing substrate 121. This single glazing embodiment provides thermal insulation in a very thin glazing unit. Note that a disadvantage is that substrate 111 may provide less mechanical integrity than glazing substrate 121.

[0104] The embodiment shown may be extended to triple glazing and further. For example, below substrate 122, a further insulating layer(s) and a further glazing substrate(s) may be included.

[0105] Figure 4 schematically shows an example of an embodiment of a glazing unit 400. For example, the glazing unit may be organized as in Figure 3. The glazing unit further comprises a sunshade 401. The sunshade may optionally comprise a pivot 410 around which sunshade 401 may be turned, possibly under control of a controller such as controller 160. The sunshade is arranged to shadow one or more edges along the side of the window frame. This is beneficial, for example, if the temperature regulating layer is provided with a heat sink in the frame of the glazing unit. By shading the edges, it is avoided that the heat sink temperature increases due to solar radiation, or at least this is reduced.

[0106] The sunshades are also applicable if the light modulator comprises multiple segments, wherein at least part of the multiple segments have edges along a side of the window frame.

[0107] Figure 5 schematically shows an example of an embodiment of a method (500) for making a light modulator system. The method refers to light modulator system 104 shown in Figure 1e, but is applicable to other light modulator systems.

[0108] Method 500 comprises: providing 501 a heat conductive liquid on a second substrate 132 for the temperature regulating layer, pressing 502 a second substrate 112 shared between the temperature regulating layer and the light modulator against second substrate 132 for the temperature regulating layer, thus forming a temperature regulating layer; optionally, a sensor 161 may be applied to second substrate 112, optionally, before the pressing, a sealant is applied along a perimeter of second substrate 132 and / or second substrate 112, to contain the heat conductive liquid in the temperature regulating layer. The sealant may be a glue, e.g., a UV or pressure-activated glue, etc. providing 503 an optical layer on second substrate 112, pressing a first substrate 111 against second substrate 112, thus forming an optical layer, optionally, before the pressing, a sealant is applied along a perimeter of second substrate 112 and / or first substrate 111, to contain the optical layer. The sealant may be a glue, e.g., a UV or pressure-activated glue, etc.

[0109] Applying a sealant is optional. Instead of a sealant, various other ways of holding the substrates together may be used. For example, the substrates may be kept together with external means, e.g., a framework, glass solder, and the like.

[0110] To create insulating layer 140, in the form of a low-pressure layer, the following method may be followed: Introducing 504 a substrate 122 and system 104 into a low-pressure chamber, pressing substrate 122 and system 104 onto each other, optionally, before the pressing, a sealant is applied along a perimeter of substrate 122 and / or system 104 to contain the low-pressure layer; the sealant may be a glue, e.g., a UV or pressure-activated glue, etc.

[0111] An advantage of using a low-pressure chamber for making the low-pressure layer is that no evacuation port is needed.

[0112] As explained in European patent applications EP24177302.7 and EP24194098.0, it is advantageous to apply a barrier to substrate 122 and / or system 104 to contain the sealant and to avoid the sealant being pushed inside the insulating layer due to atmospheric pressure before the sealant has hardened.

[0113] A light modulator system as in an embodiment may be advantageously combined with a light modulator in various ways. Below various types of light modulators are discussed than can be combined with a temperature regulating layer, and / or may be included in vacuum insulated glass.

[0114] Dynamic glazing, also known as smart glazing, may comprise a system wherein the transparency or optical properties of a glazing material are altered in response to an external electrical input. This system may allow for active control over light and heat transmission, thereby enhancing energy efficiency and user comfort in various architectural or vehicular applications. Advantageously, the dynamic glazing is combined with a low-pressure layer.

[0115] A low-pressure layer is very advantageous as in this way a very thin glazing unit may be obtained; it is not necessary though, a low-pressure layer may be replaced with any conventional insulating layer, e.g., as used in conventional glazing units.

[0116] Figures 6a-9c provide various examples of the electrode system on the first and second substrate and how they may be implemented or used in a light modulator.

[0117] Some of the known light modulators which may be provided with a temperature regulating layer and / or a low-pressure layer are based on the electrophoretic principle. For example, the substrate may comprise multiple interdigitated electrodes applied to the substrate, e.g., two electrodes, each of the multiple electrodes being arranged in a pattern across the substrate, the multiple interdigitated electrodes being arranged alternatingly with respect to each other on the substrate. Having multiple interdigitated electrodes allows local control over the electric field enabling electrophoretic control of particles.

[0118] Electrophoretic light modulators are explained more extensively herein and are used as the motivating example. In an embodiment, a light modulator comprises a first substrate and a second substrate. At least one of the first and second substrates may be according to an embodiment and may be provided with temperature regulating layer and / or a low-pressure layer. For example, the first and second substrates may be arranged with inner sides opposite to each other, using a substrate according to an embodiment. An optical layer is arranged between the first and second substrates. The electrode is arranged to modulate an electrical field in the optical layer. The optical layer comprises a fluid, e.g., liquid, comprising particles, wherein the particles are electrically charged or chargeable. The particles may be moved under control of the electrical field. For example, a controller may be configured to apply an electric potential to the electrode to obtain an electric field at the electrode providing electrophoretic movement of the particles towards or from one of the at least one electrode causing modulation of the optical properties of the light modulator. For example, optical properties may include a transition between a high-transparent state and a low-transparent state or vice versa. Note that a transition may also alter thermal properties of the light modulator.

[0119] Below a number of known light modulators are reviewed, showing some of the options in technology and electrodes. These known light modulators can advantageously be combined with temperature regulating layer and / or a low-pressure layer, optionally sharing a substrate between the vacuum-insulated part and light modulator part.

[0120] These examples also show light modulators with varying numbers of electrodes on a substrate.

[0121] International patent applications WO2011012499 A1 (included herein by reference) and WO2011131689 (included herein by reference) disclose light modulators in the form of electrophoretic display devices, e.g., e-Ink displays. A pixel of the display comprises an accumulation electrode and a field electrode, the accumulation electrode being arranged at a storage area for accumulating charged particles away from an aperture area, and the field electrode occupying a field-electrode area being at least a part of an aperture area of the pixel, the charged particles being movable between the accumulation electrode and the field electrode. In an embodiment, two electrodes are applied on a single substrate. These electrophoretic display devices may be provided with temperature regulating layer and / or a low-pressure layer, e.g., arranged in parallel to the electrophoretic display device. The electrophoretic display devices, temperature regulating layer, and / or low-pressure layer advantageously may share a common substrate, although this is not necessary.

[0122] US patent 10921678 with title 'Electrophoretic device', included herein by reference, shows an electrophoretic device having only one patterned electrode on one of two substrates. For example, the one substrate with an electrode according to US 10921678 may be replaced with a substrate according to an embodiment comprising one single electrode. For example, an embodiment comprises a first transparent substrate with a field electrode and a second substrate opposite the first substrate, with an accumulation electrode. The first substrate and the second substrate enclose a pixel with a fluid and particles. In use, an applied electric field to the field electrode and the accumulation electrode provides movement of the particles from the field electrode to the accumulation electrode and vice versa. Any of these cited electrophoretic or dielectrophoretic light modulators may be adapted by including a temperature regulating layer and / or one or more low-pressure layers according to an embodiment.

[0123] US patent 8054535B2 (included herein by reference) and US patent 8384659b2 (included herein by reference) show alternative examples of electrophoretic light modulators in one of two substrates having two patterned electrodes.

[0124] Patterned electrodes are also used in dielectrophoretic light modulators. For example, US patent application US2005185104A1 (included herein by reference) and US20180239211A1 (included herein by reference) show dielectrophoretic light modulators having a substrate with a patterned electrode. Any of these cited electrophoretic or dielectrophoretic light modulators may be adapted by including a temperature regulating layer and / or one or more low-pressure layers areas according to an embodiment.

[0125] The paper "Reversible Metal Electrodeposition Devices: An Emerging Approach to Effective Light Modulation and Thermal Management," included by reference, also shows a substrate on which a patterned electrode is applied. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0126] An embodiment of a substrate may be used in an electrochromic device (ECD). An electrochromic device (ECD) controls optical properties such as optical transmission, absorption, reflectance, and / or emittance in a continual but reversible manner on application of voltage (electrochromism). This property enables an electrochromic device to be used for applications like smart glass, electrochromic mirrors, and electrochromic display devices. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0127] An electrochromic device is described, e.g., in the paper "Silver grid electrodes for faster switching ITO free electrochromic devices" by António Califórnia et al., included herein by reference. The paper describes the preparation of an electrochromic device, in this case, one which is ITO-free. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0128] An electrochromic device uses electrically conductive electrodes applied on a substrate. The cited paper uses silver grids, made using silver ink, as electrically conductive electrodes. An electrochromic device may comprise an electrochromic material. The cited paper uses poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). In an electrochromic device, at least one electrode, e.g., the electrically conductive electrode, is applied to a substrate. The electrode being arranged in a pattern across the substrate. The cited paper discloses two different grid patterns: a regular hive and a regular ladder design. See table 1 and figure 3 of the cited paper. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0129] Electrodes may be applied to a substrate by screen-printing on a substrate, in the case of the cited paper, polyethylene terephthalate (PET). The electrodes are typically an electrically conductive material, e.g., a metal or metal oxide. In the cited paper, silver ink was used to screen print the grids on PET using a RokuPrint RP 2.2 equipment and a 180 wired mesh. The samples were allowed to dry in an oven at 130°C for 15 min. On top of these silver grids, one or two layers of PEDOT:PSS SV3 were posteriorly printed by screen printing. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0130] Another example of an electrochromic device is given in US patent 5161048, with title "Electrochromic window with metal grid counter electrode and acidic polyelectrolyte", included herein by reference. For example, an electrochromic device may comprise a transparent electrochromic film and an ion-conductive layer disposed between a pair of electrodes. The metal grid electrode is used for the electrodes. Figure 1 of the patent shows a metal grid according to the cited patent. To form the counter electrode, a metal grid is disposed adjacent to the second glass substrate.

[0131] For example, in an embodiment of an electrochromic device, the electrochromic device may comprise a transparent substrate, an electroconductive electrode member, a transparent electrochromic film in contact with said electroconductive electrode member, an ion-conductive polymer in contact with said electrochromic film; and a patterned conductive electrode in contact with said ion-conductive polymer. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0132] A substrate according to an embodiment can be beneficially applied in several other technologies. For example, the light modulator may be a dielectrophoretic light modulator, e.g., as shown in US20050185104 A1, included herein by reference. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0133] A substrate as in an embodiment may also be used in other electrowetting and OLED applications. In OLED and electrowetting, electrodes are needed on only one of the substrates. The substrate with electrodes may be according to an embodiment including a low-pressure layer and / or a temperature regulating layer.

[0134] Yet other dynamic glass technologies may be used.

[0135] For example, an optical layer for a light modulator, e.g., in dynamic glazing, may use LCD (Liquid Crystal Display) technology. For example, the optical layer may comprise liquid crystal molecules that can be aligned to control the amount of light passing through the display. When an electric current is applied to the liquid crystal molecules, they change their alignment and modify the way that light passes through the material. The optical layer with LCD material may be placed between two layers of glass or plastic and connected to an electrical circuit. By controlling the electric current applied to the LCD material, the amount of light passing through the glazing may be adjusted. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0136] An optical layer for a light modulator, e.g., in dynamic glazing, may use Suspended Particle Device (SPD) technology. The optical layer may comprise particles suspended within a thin film or laminate. By applying an electrical current to the SPD film, the particles align and modify the amount of light passing through the material, allowing for dynamic control of the glazing. When the electrical current is turned off, the suspended particles randomize and allow more light to pass through, creating a clear or transparent effect. When the electrical current is turned on, the particles align and absorb more light, creating a darker or tinted effect. A temperature regulating layer and / or a low-pressure layer according to an embodiment may be included herein.

[0137] In an application of a light modulator system for glazing, both substrates are typically transparent. In other applications, e.g., in television, e-readers, etc., only one substrate may be transparent.

[0138] Figure 6b schematically shows an example of an embodiment of a substrate. The substrate is particularly useful for use in a light modulator, e.g., of a kind described herein. Across the substrate, an electrode system is applied in the form of multiple interdigitated electrodes. Shown in figure 6b are two interdigitated electrodes.

[0139] The motivating example use of the substrate is in an electrophoretic light modulator. Typically, an electrophoretic light modulator comprises at least two substrates, each having at least two electrodes at each of the substrates; this is not necessary though, for example, an electrophoretic light modulator may comprise a single substrate with 2 electrodes and an opposite substrate with 1 electrode. In any case, preferably, at least one of the substrates in the light modulator is according to an embodiment.

[0140] An embodiment of a light modulator comprises a first substrate according to an embodiment and a second substrate. The first and second substrates are arranged with inner sides opposite to each other. At least one electrode is applied to the inner side of the first substrate. An optical layer is arranged between the first and second substrates. A controller is configured to apply an electric potential to the at least one electrode causing modulation of the optical properties of the light modulator. One or both of the first and second substrates are transparent and / or translucent.

[0141] There are many different kinds of light modulators that use at least one electrode applied to a substrate. The optical layer and controller may be arranged to modulate optical properties using effects that depend on the potential on the electrode; examples include the dielectrophoretic effect and the electrophoretic effect. For example, optical modulation may comprise the modulation of particles arranged in the optical layer. The number of electrodes may range from one on a single substrate, to multiple electrodes on one or both substrates.

[0142] The optical layer arranged between the first and second substrates may comprise particles, e.g., suspended in a fluid. The controller may be configured to apply an electric potential to the electrodes causing the particles to move thus modulating the optical properties of the light modulator.

[0143] In an embodiment, the particles comprise electrically charged or chargeable particles, and the controller is configured to apply an electric potential to the electrode to obtain an electric field providing electrophoretic movement of the particles. In an embodiment, the electric field is arranged between at least two electrodes arranged on the same substrate or arranged on different substrates.

[0144] In an embodiment, the particles comprise dielectric particles, and the controller is configured to apply an electric potential to the electrode to apply an electric field gradient to the particles enabling the particles to be moved under the action of dielectrophoretic forces.

[0145] The controller may apply an electric signal to one or more of the electrodes. Embodiments that control dielectrophoretic forces may use a signal that comprises a DC signal and / or an AC signal. Embodiments that control electrophoretic forces may use a signal that comprises a DC signal and / or an AC signal.

[0146] Shown in figure 6b are two electrodes on the same surface. The two electrodes are indicated in figure 6b in two different dashing styles. There could be more than two electrodes on the same side of the substrate, e.g., to facilitate more fine-grained control of voltage differences across the substrate. The electrodes are applied to a same side of the substrate. Applying electrodes to a substrate may be done lithographically, e.g., using a mask representing the electrode(s) pattern. Electrodes may also be applied by embedding them in the substrate.

[0147] An electrode is electrically connected, e.g., has the same electric potential everywhere. An electrode may comprise a driving bus and main lines. At least, the main lines are interdigitated with main lines of a further electrode. Typically, the electrodes extend in a substantially straight line across the substrate, while the main lines are convoluted.

[0148] In an embodiment, the two substrates of a light modulator each have two electrodes arranged at their inner surface. Though, as mentioned, multiple electrodes on one or both substrates are not needed. For example, an embodiment of a light modulator comprises a first substrate and a second substrate. For example, the first substrate may comprise one electrode, the second substrate may not comprise electrodes. For example, the first substrate may comprise two electrodes, the second substrate may comprise one electrode. For example, the first substrate may comprise two electrodes, the second substrate may comprise two electrodes. For example, the first substrate may comprise more than two electrodes, the second substrate may comprise two or more electrodes.

[0149] Light modulators, wherein each substrate comprises two electrodes are used as a motivating example, though. Designs of substrates featuring two electrodes may be adapted to have a single electrode, e.g., by connecting the two electrodes, or by removing one of the electrodes. Adapting a substrate in such a manner may make it suitable for use in different technologies.

[0150] Each of the multiple electrodes is arranged in a pattern across the substrate. The multiple electrodes are arranged alternatingly with respect to each other on the substrate. Typically, an electrode comprises multiple main lines, that each stretch across the substrate. The main lines of the electrodes alternate, e.g., interdigitate. For example, in figure 6b the first electrode comprises main lines 611-614, and the second electrode comprises main lines 621-624. The electrodes are each driven by its driving bus. Figure 6b shows two driving buses: driving bus 610 and driving bus 620. The electrodes also serve to connect the main lines together. For example, in figure 6b, the driving bus 610 drives and connects main lines 611-614; and the driving bus 620 drives and connects main lines 621-624. There can be more main lines than the four shown in this example. The use of main lines is advantageous as it reduces the length of the electrodes, but it is not necessary. A design using only one main line per electrode is not impossible, though having multiple is advantageous.

[0151] The driving buses may be adapted to form a contact area to enable electrical connection to at least the one or more driving electrodes applied on the first substrate, e.g., a connection from outside the light modulator. This is not necessary, and a separate contact area, e.g., additional to driving buses 610 and 620 may be provided in an embodiment.

[0152] The multiple main lines of the first and second electrodes are arranged alternatingly with respect to each other on the substrate.

[0153] In this example, there are no other connections between the main lines of an electrode than through the common driving bus. In an embodiment, an electrode comprises a mesh electrode, that is, it may have additional electrical connections added between electrode lines of the same electrode. This increases the reliability of the electrode. Such additional connections typically cross an electrode line of another electrode, which may be resolved by placing the additional electrical connection in part on a different level with respect to the substrate than the electrode line being crossed. For example, one may place the entire electrodes at a different level than another electrode. In this way, additional connections may be placed without short circuits arising.

[0154] A motivating application for a substrate such as substrate 600 is in smart glazing, e.g., a light modulator, which may be applied in domestic housing, offices, greenhouses, cars, and the like. The level of transparency or reflectivity of the smart glazing can be adapted electrically. For example, in smart glazing, two substrates such as substrate 600 would be stacked so that the sides on which the two electrodes are applied face each other. A fluid with particles is enclosed between the two substrates. Smart-glazing embodiments are further discussed below. In an embodiment, electrodes, e.g., two or more electrodes are applied to one surface of each substrate. There could also be one, two, or more electrodes on the other surface of substrate 600, e.g., to facilitate stacking of three or more substrates. For example, substrate 600 may be used for substrate 360 and one of substrates 310 and 320.

[0155] Some embodiments below show examples of modulating a transparency or reflectivity level. Light modulators may be adapted for other optical effects. For example, if desired, embodiments could be modified to different levels of translucency instead of different levels of transparency. If desired, the type of particle that is used in an embodiment can be varied, e.g., to particles that differ in which wavelengths they absorb or reflect, and how specular or diffuse the reflection is. For example, in an embodiment, a light modulator can modulate different levels of reflection. Particles can also emit light. Stacking multiple optical layers further increases the possibilities.

[0156] Having two sets of alternating main lines is sufficient to provide electrically adaptable glazing; due to the alternating two sets, the electric field at any part of the substrate can be controlled as two opposite electrodes border the part from two opposing sides.

[0157] Interestingly, the pattern in which the electrodes stretch across the substrate may be created by multiple repeated building blocks. Shown in figure 6b, the electrodes on substrate 600 show four blocks: blocks 641, 642, 643, and 644 which are all substantially the same. The number of building blocks may be larger than four. The building blocks repeat in both directions across the substrate, e.g., a first direction 691, e.g., an x-direction, shown horizontally in the figure, and a second direction 692, e.g., a y-direction, shown vertically in the figure. Using building blocks is advantageous as it allows manufacture using a stepper machine; using building blocks is not necessary.

[0158] For example, figure 6a schematically shows an example of an embodiment of a building block 640. Building block 640 comprises multiple interdigitated electrodes extending in at least 2 directions across the building block. Shown in figure 6a are four electrodes: electrode 631-634. When the building blocks are repeated across a substrate in two directions, the electrodes in the building block will form the electrodes, e.g., form the multiple main lines of the electrodes.

[0159] The electrodes that are formed by repeating building blocks are connected to the driving buses. Typically, electrode lines in a building block are connected to electrode lines in neighboring blocks by merging corresponding electrode lines; this is not necessary though, between repeated building blocks, connection zones can be inserted that connect corresponding electrode lines.

[0160] This step can connect up multiple main lines together, thus forming a single electrode. Figure 6b shows two connecting zones 619 and 629 in which the main lines belonging to the same electrode are connected to driving bus 610 and driving bus 620, respectively.

[0161] Figures 7a-7f schematically show examples of substrates with interdigitated electrodes. These may be embodied on a substrate with two electrodes, e.g., by alternatingly connected electrodes. Figures 7a-7d may also be embodied on a substrate with multiple electrodes, e.g., by connecting in sequences of 3 or 4 or more electrodes.

[0162] Figures 7e and 7f show designs with two electrodes on the surface of the substrate. Either design could be modified to have only a single electrode on the surface of the substrate, e.g., by removing one of the two electrodes. For example, such a modified design could be used in a light modulator that uses a substrate with a single electrode.

[0163] The designs shown can be realized in a single plane, without having crossing electrodes. In particular, if these designs are connected to two driving buses, no crossing electrodes are needed. When more than two electrodes are used, or if more complicated electrode patterns are used, then crossing of the electrodes may be used, or may even become necessary. Such crossings are possible however for example, at the location where two electrode lines cross, a dielectric material may be arranged between the electrodes. For example, such an insulator may be deposited at the crossing location. For example, a first electrode is in a first plane of the substrate and a second electrode is in a second plane of the substrate.

[0164] Two substrates according to an embodiment may be combined to form a light modulator. The light modulator is particularly suited to glazing. An exemplary embodiment of a light modulator is shown below.

[0165] Figure 8a schematically shows an embodiment of a light modulator 10, which may be applied in smart glazing.

[0166] Reference is made to patent application PCT / EP2020 / 052379, which is included herein by reference; this application comprises advantageous designs for light modulators, which may be further improved, e.g., by including electrodes, building blocks, and / or substrates as explained herein.

[0167] Light modulator 10 can be switched electronically between a transparent state and a non-transparent state and vice versa, or between a non-reflective state and a reflective state and vice versa. Light modulator 10 comprises a first substrate 11 and a second substrate 12 arranged opposite to each other. On an inner side of first substrate 11, at least two electrodes are applied: shown are electrodes 13a, 13b. These at least two electrodes are together referred to as electrodes 13. On an inner side of second substrate 12, at least two electrodes are applied: shown are electrodes 14a, 14b. These at least two electrodes are together referred to as electrodes 14. One or more of substrates 11 and 12 may be provided with one or more contact areas to enable electrical connection to at least the one or more electrodes applied on the substrate(s).

[0168] A fluid 15 is provided between said substrates. The fluid comprises particles 30, e.g., nanoparticles and / or microparticles, wherein the particles are electrically charged or chargeable. For example, particles may carry a charge on their surface intrinsically. For example, the particle may be surrounded by a charged molecule. The fluid may be a liquid.

[0169] The electrodes are arranged for driving particles 30 to move towards or away from electrodes, depending on the electric field applied. The optical properties, in particular the transparency or reflectivity of the light modulator, depend on the location of particles 30 in the fluid. For example, a connection may be provided for applying an electric field to the electrodes.

[0170] At least one, but preferably both electrodes 13 and 14 are according to an embodiment, though they are shown schematically in the figures.

[0171] In an example, substrate 11 and substrate 12 may be optically transparent outside of the electrodes, typically >95% transparent at relevant wavelengths, such as >99% transparent. Taking electrodes into account, transparency can be much lower, e.g., 70%. The term "optical" may relate to wavelengths visible to a human eye (about 380 nm- about 750 nm), where applicable, and may relate to a broader range of wavelengths, including infrared (about 750 nm - 1 µm) and ultraviolet (about 10 nm-380 nm), and sub-selections thereof, where applicable. In an exemplary embodiment of the light modulator, a substrate material is selected from glass, and polymer.

[0172] In another example, one substrate, such as a bottom substrate 12, may be reflective or partially reflective, while the top substrate 11 is transparent. The optical properties, in particular the reflectivity of the light modulator, depend on the location of particles 30 in the fluid. When the panel is in the open state (vertical drive), the particles will mostly be located between opposite electrodes of the two substrates, such that incident light can pass through the transparent top substrate and the optical layer relatively unhindered and is reflected or partially reflected on the bottom substrate.

[0173] The distance between the first and second substrates is typically smaller than 30 µm, such as 15 µm. In an exemplary embodiment of the light modulator a distance between the first and second substrates is smaller than 500 µm, preferably smaller than 200 µm, preferably less than 100 µm, even more preferably less than 50 µm, such as less than 30 µm.

[0174] In an example, the modulator may be provided in a flexible polymer, and the remainder of the device may be provided in glass. The glass may be rigid glass or flexible glass. If required, a protection layer may be provided on the substrate. If more than one color is provided, more than one layer of flexible polymer may be provided. The polymer may be polyethylene naphthalate (PEN), polyethylene terephthalate (PET) (optionally having a SiN layer), polyethylene (PE), etc. In a further example, the device may be provided in at least one flexible polymer. As such, the modulator may be attached to any surface, such as by using an adhesive.

[0175] Particles 30 may be adapted to absorb light and thereby prevent certain wavelengths from passing through. Particles 30 may reflect light; for example, the reflection may be specular, diffusive, or in between. A particle may absorb some wavelengths and reflect others. Particles may also or instead emit light, e.g., using phosphorescence, fluorescence, or the like. Even the fluid may emit light, whose emittance is modulated by changing the location of particles.

[0176] In an exemplary embodiment of the light modulator, a size of the nanoparticles is from 20-1000 nm, preferably 20-300 nm, more preferably smaller than 200 nm. In an exemplary embodiment of the light modulator, the nanoparticles / microparticles may comprise a coating on a pigment, and preferably comprise a core. In an exemplary embodiment of the light modulator, the coating of the particles is made from a material selected from conducting and semiconducting materials.

[0177] In an exemplary embodiment of the light modulator, the particles are adapted to absorb light with a wavelength of 10 nm-1 mm, such as 400-800 nm, 700 nm to 1 µm, and 10-400 nm, and / or are adapted to absorb a part of the light with a wavelength-range falling within 10 nm-1 mm (filter), and combinations thereof.

[0178] In an exemplary embodiment of the light modulator, the particles are electrically charged or chargeable. For example, a charge on the particles may be 0.1e to 10e per particle (5*10 -7< -0.1C / m 2< ).

[0179] In an exemplary embodiment of the light modulator, the fluid is present in an amount of 1-1000 g / m 2< , preferably 2-75 g / m 2< , more preferably 20-50 g / m 2< , such as 30-40 g / m 2< . It is a big advantage that with the present layout much less fluid, and likewise particles, can be used.

[0180] In an exemplary embodiment of the light modulator, the particles are present in an amount of 0.01-70 g / m^2, preferably 0.02-10 g / m^2, such as 0.1-3 g / m^2.

[0181] In an exemplary embodiment of the light modulator, the particles have a color selected from cyan, magenta, and yellow, and from black and white, and combinations thereof.

[0182] The light modulator can be also configured to only, or primarily, modulate non-visible light such as UV or near-IR, e.g., respectively in the range of about 10 nm-380 nm, and in the range of about 750 nm - 1 µm.

[0183] In an exemplary embodiment of the light modulator, the fluid comprises one or more of a surfactant, an emulsifier, a polar compound, and a compound capable of forming a hydrogen bond.

[0184] Fluid 15 may be an apolar fluid with a dielectric constant less than 15. In an exemplary embodiment of the light modulator, the fluid has a relative permittivity εr of less than 100, preferably less than 10, such as less than 5. In an exemplary embodiment of the light modulator, fluid 15 has a dynamic viscosity of above 10 mPa.s.

[0185] Electrodes 13a, 13b and electrodes 14a, 14b are in fluidic contact with the fluid. The fluid may be in direct contact with the electrodes, or indirectly, e.g., the fluid may contact a second medium with the electrode, such as through a porous layer. In an embodiment, the electrodes cover about 1-30% of the substrate surface. In an embodiment, the electrodes comprise an electrically conducting material with a resistivity of less than 100 nS2m (at 273K; for comparison, typically used ITO has 105 nS2m), which is similar to an electrical conductivity >1*10 7< S / m at 20°C).

[0186] In an embodiment of the light modulator, electrodes comprise copper, silver, gold, aluminum, graphene, titanium, indium, and combinations thereof, preferably copper. The electrodes may be in the form of microwires embedded in a polymer-based substrate; for example, copper microwires.

[0187] A connection for applying an electric field to the electrodes, wherein the applied electric field to the electrodes provides movement of the nano- and microparticles from a first electrode to a second electrode and vice versa. A connection for applying an electric field to the electrodes may be provided. For example, in an exemplary embodiment of the light modulator, an electrical current is between -100 to +100 µA, preferably -30 to +30 µA, more preferably -25 to +25 µA. For example, a power provider may be in electrical connection with the at least two electrodes. The power provider may be adapted to provide a waveform power. At least one of amplitude, frequency, and phase may be adaptable to provide different states in the light modulator. For example, these aspects of the power may be adapted by a controller 16. The controller 16 may be connected to one or more contact areas of the light modulator.

[0188] Light modulator 10 may comprise one or more segments, a segment being a single optically switchable entity, which may vary in size. The substrates enclose a volume, which may be a segment, at least partly.

[0189] The present device may comprise a driver circuit for changing the appearance of (individual) segments by applying an electric field. As such also the appearance of the light modulator, or one or more parts thereof, may be changed. For example, a segment may have an area of at least 1 mm 2< . The present design allows for stacking to allow for more colors; e.g., for full-color applications, a stack of two or three modulators could provide most or all colors, respectively.

[0190] Having one or more segments allows the light modulator to be controlled locally; this is advantageous for some applications but not necessary. For smart glazing, a light modulator may be used with or without segments. For example, applied in smart glazing, transparency or reflectivity may be controlled locally, e.g., to block a sun-patch without reducing transparency or reflectivity in the whole window. Segments may be relatively large, e.g., having a diameter of at least 1 mm, or at least 1 cm, etc.

[0191] In an exemplary embodiment of the light 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 to be opposite each other. In aligned substrates, electrodes on different substrates fall behind each other when viewed in a direction orthogonal to the substrates. When the light modulator is disassembled, and the substrates are both arranged with electrodes face-up, then the electrode patterns are each other's mirror image.

[0192] Aligning substrates may increase the maximum transparency or reflectivity of the light modulator. On the other hand, when selecting a light modulator for more criteria than the range of transparency or reflectivity, etc., it may be better not to align or not fully align the two substrates. Light modulators can be stacked. For example, two stacked light modulators can be made from three substrates, wherein the middle one has electrodes on both its surfaces. In an embodiment of the light modulator, optionally at least one substrate 11,12 of a first light modulator is the same as a substrate 11,12 of at least one second light modulator. For stacked modulators, alignment may also increase maximum transparency or reflectivity, but it may be detrimental to other considerations, e.g., diffraction.

[0193] Figure 8b schematically shows an example of an embodiment of a light modulator 40. Light modulator 40 is similar to light modulator 10, except that it comprises multiple optical layers; in the example as shown, two optical layers. There may be more than two optical layers. Each optical layer is arranged between two substrates. Light modulator 40 can be regarded as a stack of two-substrate light modulators as in figure 8a. As shown, light modulator 40 comprises three substrates: first substrate 41, second substrate 42, and third substrate 43. Between substrates 41 and 42 is an optical layer, and between substrates 42 and 43 is an optical layer. The optical layers may be similar to those in light modulator 10. A controller 46 is configured to control the electrical current on the electrodes of the substrates. For example, in figure 8b, controller 46 may be electrically connected to at least 4 times 2 equals 8 electrodes.

[0194] Interestingly, the particles in the multiple optical layers may be different so that the multiple layers may be used to control more optical properties of the light modulator. For example, particles in different optical layers may absorb or reflect at different wavelengths, e.g., may have a different color. This can be used to create different colors and / or different color intensities on the panel by controller 46. For example, a four-substrate panel may have three optical layers with different color particles, e.g., cyan, yellow, and magenta, respectively. By controlling the transparency or reflectivity for the different colors, a wide color spectrum may be created.

[0195] The surfaces of the substrates that face another substrate may be supplied with two or more patterns, e.g., as in an embodiment. For example, the outer substrates 41 and 43 may receive electrodes only on an inner side, while the inner substrate, e.g., substrate 42, may have electrodes on both sides.

[0196] Substrates 41 and 42 may together be regarded as an embodiment of a light modulator. Likewise, substrates 42 and 43 may together be regarded as an embodiment of a light modulator. One or more of substrates 41, 42, and 43 may be provided with a contact area to connect to the electrodes.

[0197] Figure 8c schematically shows an example of an embodiment of a car 20 having smart glazing for windows 21. This is a particularly advantageous embodiment since, while driving, the level of incident lighting can change often and rapidly. Using smart glazing in a car has the advantage that light levels can be maintained at a constant level by adjusting the transparency of the car windows. Moreover, the reduced diffraction effect improves safety as it reduces driver distraction. Car 20 may comprise a controller configured for controlling the transparency or reflectivity of windows 21. Smart glazing can also be used in other glazing applications, especially where the amount of incident light is variable, e.g., buildings, offices, houses, greenhouses, and skylights. Skylights are windows arranged in the ceiling to allow sunlight to enter the room.

[0198] The light modulator may have two optical states, e.g., a transparent state and a non-transparent state, or a non-reflective state and a reflective state. The light modulator, e.g., light modulator 10 or light modulator 40, may be configured to switch to the second optical state, e.g., the non-transparent state or to the reflective state by creating an alternating voltage on at least one of the first and second substrates, applying an alternating current between at least a first electrode and a second electrode on the first substrate and / or between a first electrode and a second electrode on the second substrate, and switch to the first optical state, e.g., the transparent state or to the non-reflective state by creating an alternating voltage between the first and second substrate, applying an alternating current between a first electrode on the first substrate and a first electrode on the second substrate, and / or between a second electrode on the first substrate and a second electrode on the second substrate.

[0199] The light modulator may also demonstrates multiple intermediate transparency states between the 2 optical states. For example, the light modulator may support a gray scale of transparency states between a maximally transparent and maximally opaque state. The same holds for other optical properties, e.g., intermediate reflective properties.

[0200] The electrode pattern on the first substrate is arranged at least in part in the same pattern as a second electrode on the second substrate. Typically, the electrodes oppose each other, but the pattern of the first electrode and second electrode may also be shifted with respect to each other.

[0201] A protective coating may be provided on at least a part of the inner surface area of at least one of the first substrate and the second substrate. A driving signal applied to electrodes typically has a varying voltage. For example, a power provider may be operated at an AC frequency for switching to a transparent state or to a non-transparent state. Such a signal may have a frequency between, say, 1-1000 Hz. A balanced electrolysis current may be obtained by continuously switching the polarity of oppositely charged electrodes on the first and on the second substrates and / or between the first and the second substrates.

[0202] Figures 9a-9b schematically show a side view of an embodiment of a light modulator in use. In this figure, only the electrodes are shown.

[0203] Applying an electric field to the electrodes on the substrates causes an electrical force on the particles. Using this effect, the particles can be moved around, and so different transparency or reflectivity states can be caused in the light modulator. A controller may control the electric field, e.g., its amplitude, frequency, and phase. In an embodiment, the controller is connected to at least four electrodes: two for each substrate. But more electrodes may be used and connected to the controller; for example, more than 2 electrodes may be used for a substrate to better fine-tune grayscaling and driving to a non-transparent or reflective state. Multiple electrodes may also be used to support multiple segments on the substrate.

[0204] Figure 9a shows the light modulator without an electric field being applied. No electric force is yet applied on particles 30 suspended in fluid 15, in figure 9a.

[0205] In the configuration shown in figure 9a, a conducting electrode pattern, arranged on the top substrate, is completely or substantially aligned with a conducting electrode pattern on the bottom substrate. The conducting electrode pattern may be deposited on a transparent or (partially) reflective glass substrate or may be embedded in a plastic substrate, etc.

[0206] Alignment between the top-electrode pattern and the bottom electrode pattern contributes to a wider range of achievable levels of transparency or reflectivity. However, alignment is not needed, as similar effects can be obtained without alignment. Without alignment, a range of transparency or reflectivity is likewise obtained.

[0207] Note that in these examples, reference is made to the top substrate and the bottom substrate to refer to the substrate that is higher or lower on the page. The same substrates could also be referred to, e.g., as the front substrate and back substrate, since in a glazing application, the substrates would be aligned vertically rather than horizontally.

[0208] Figure 9b shows the light modulator wherein, say at an instance P1, a potential +V1 is applied to each microwire electrode on the top substrate, while a negative voltage, say -V1, is applied to each microwire electrode of 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 electrodes 14. The difference in potential causes negatively charged particles to flow to the vicinity of the electrodes of the top substrate, where the particles will substantially align with the top electrodes. As a result, if both the top and bottom substrates are transparent, the transparency of light modulator 10 will increase. Likewise, if, e.g., the top substrate is transparent and the bottom substrate is reflective, the reflectivity of light modulator 10 will increase. If the solution contains positively charged particles, they will flow to the vicinity of the electrodes of the bottom substrate, where those particles will substantially align with the bottom electrodes.

[0209] A similar transparency can be achieved when in a second instance, P2, of the on-state, the voltages of the top electrodes and bottom electrodes are reversed in contrast to the instance of P1. In the instance P2, the voltage of each electrode on the top substrate is now supplied with a negative potential -V1 while the voltages of the aligned electrodes of the bottom substrate are supplied with a positive potential. This state is similar to the state shown in figure 9b, but with top and bottom substrates reversed. In this configuration, the transparency of light modulator 10 is also high. If reflective particles are used, then reflectivity is low.

[0210] Interestingly, by switching between a positive potential at electrodes at the top substrate, e.g., as shown as electrodes 13 in figure 9b (and a negative potential on electrodes 14), and a positive potential at electrodes at the bottom substrate, e.g., as shown as electrodes 14 in figure 9b, the transparency or non-reflectivity can be maintained, while decreasing corrosion damage to the electrodes. This alternating electric field can be achieved by applying alternating electric potentials to the top and bottom electrodes.

[0211] Applying an AC waveform is optional, but it is a useful measure to increase the lifetime of the light modulator by reducing corrosion. Corrosion can form, for example, when using copper electrodes, since copper ions dissolve in an ionic fluid at one substrate and flow to electrodes on the opposite substrate, where they deposit. By applying a waveform, the direction of copper ion transport is frequently reversed, thus reducing corrosion damage. Between the two instances P1 and P2, the corrosion current between the two substrates is balanced or substantially, e.g., >95%, balanced, e.g., as corrosion rate of an electrode of the top plate occurs, there is a balancing deposition of copper on the bottom electrode between each instance of time, P1, and vice versa in instance P2. Therefore, the particles are transitioning or migrating continuously between top and bottom electrodes, and the light modulator or smart window is always in the on-state while the dynamic electrolysis current between the top and bottom electrodes is constant, thus there is no or a negligible net loss of electrode material on the top and bottom substrates.

[0212] Figure 9c shows how a state of decreased transparency or increased reflectivity can be obtained. An alternating voltage is applied on the same substrate. For example, in an embodiment, a potential +V2 is applied to a first electrode and the next immediate neighboring electrode has an opposite potential -V2 etc., as shown in fig. 8c. This can be obtained by applying the potential +V2 to electrode 13a and the opposite potential -V2 to electrode 13b. On the opposite substrate, the potential +V2 may be applied to electrode 14a and the opposite potential -V2 to electrode 14b. For example, the electrodes may be arranged so that the electrodes on the substrates are aligned; an electrode on the top substrate having an opposite electrode on the bottom substrate, and vice versa. For example, to decrease transparency or increase reflectivity, the opposite electrode may receive the same potential, while neighboring electrodes receive an opposite potential. An embodiment is shown in figure 9c, wherein four electrodes are indicated with the reference numbers 13a, 13b, 14a, and 14b, and the rest of the electrodes continue to alternate.

[0213] By using this AC drive cycle between top and bottom substrates, diagonal and lateral electric fields are generated between the two substrates thereby causing haphazard diffusion of the particles, thereby creating the closed state of the light modulator. As a result of this configuration, the particles migrate diagonally and laterally between the top and bottom substrates and diffusion of particles into the visible aperture of the light modulator contributes to the closed, opaque state of the light modulator.

[0214] As for the transparent state shown in figure 9b, a waveform may be applied to the electrodes, e.g., so that electrodes that are shown in figure 9b with a positive potential become negative and vice versa. As in figure 9b, applying a waveform, e.g., between electrodes 13a and 13b and between 14a and 14b reduces corrosion damage to the electrodes.

[0215] The AC drive cycle may be implemented by using an interdigitated line configuration combining the top and bottom electrode configuration shown in plan view in figures 6a, 6b, 7a-7f, etc.

[0216] The extent to which transparency or reflectivity is increased or decreased in figures 9b and 9c depends on the voltage and frequencies difference. By varying the voltage difference, the amount by which the transparency or reflectivity increases, respectively, decreases, is controlled. For example, a curve representing light transmission versus voltage may be determined, e.g., measured. To obtain a particular level of light transmission, e.g., a particular transparency, e.g., a particular grayscale level, the corresponding voltage, e.g., AC voltage may be applied. By interpolating the signals for a transparent or for a non-transparent state, levels in between transparent and non-transparent may be obtained. Likewise, a curve representing light reflection versus voltage may be determined, e.g., measured. To obtain a particular level of reflectivity, the corresponding voltage, e.g., AC voltage may be applied. By interpolating the signals for a reflective or for a non-reflective state, levels in between reflective and non-reflective may be obtained.

[0217] Different electrode patterns may be used for a light modulator. The electrode patterns may each provide a range of grayscales, e.g., levels of transparency or reflectivity, that the light modulator can attain. However, the particular range of grayscale for any particular electrode pattern may be different from another electrode pattern. In other words, although different patterns give an increased transparency or reflectivity or an increased opacity, the exact response to a drive signal depends on many factors, including the particular pattern that is used. The variations in the optical properties of a light modulator may have a fine resolution, e.g., below 1 mm. Note that no pixelation of the light modulator is needed to achieve different optical patterns, e.g., logos, visible in the light modulator.

[0218] This effect may be used to embed visible images in the light modulator by locally changing the electrode pattern on the substrates of a light modulator. For example, one may locally have grayscales that have a permanent offset in grayscale relative to each other, because of a different electrode pattern. For example, by locally changing the electrode pattern or its pitch, the maximum transparency or reflectivity can be altered.

[0219] The result is an area on the light modulator which has a different intensity of grayscale, e.g., a different grayscale, or of coloring. The area may have the same color point, though. In an embodiment, they may switch together with the rest of the window, although at a different rate. For example, even if the same voltage is applied to the electrodes in two different areas, they cause a different transparency state, e.g., different transmission level, due to different electrode patterns. For example, a curve representing transmission versus voltage may be shifted. For example, if voltage control is changed in the same way in both areas, then in both areas light transmission may change, but with a different amount. An area may also be made less responsive to a drive signal by reducing the density of electrodes; in particular, an area may be made not to switch at all, e.g., by not applying electrodes in the area.

[0220] For example, the electrode material may be copper, aluminum, gold, indium-tin oxide (ITO), etc. ITO is transparent while Cu / Al is reflective, thus using a different electrode material, a different appearance may be obtained, irrespective of the voltage driving. Likewise, different materials with different resistance will give rise to a different electric field. For example, ITO will have a smaller electric field, even though driven with the same voltage.

[0221] An embodiment of a method of modulating light comprises applying an electric potential to multiple electrodes applied to two opposing substrates according to an embodiment to obtain an electric field between the multiple electrodes providing electrophoretic movement of the particles towards or from one of the multiple electrodes causing modulation of light shining through the substrates, wherein the two opposing substrates are as in an embodiment.

[0222] Various modes of operation are supported by an embodiment of a four-electrode light modulator system.Horizontal drive

[0223] Horizontal drive is a mode in which lateral electric fields are created along the substrate. The light modulator may apply an alternating voltage on the interdigitated electrodes to cause the particles in the optical layer to move parallel to the substrate, thus decreasing transparency.Vertical drive

[0224] Vertical drive is a mode in which particles are aligned orthogonally to the substrates. Electrodes opposite to each other on opposite substrates receive a different voltage.Maintaining a grayscale

[0225] The light modulator drive system may apply 0 voltage on the electrodes most of the time, but if the grayscale is dropping due to the particles dispersing, then briefly the electrodes and may be driven as in vertical drive.

[0226] In all three modes, the driving may use DC or AC signals. Preferably, AC signals are used.

[0227] Figure 10 schematically shows an example of an embodiment of a method 700 for making vacuum insulated glass. Method 700 comprises providing (701) a first substrate, the first substrate having a sealant barrier applied around a perimeter of a surface of the first substrate, providing (702) a second substrate having a surface, applying (703) a sealant on the surface of the first or second substrate, introducing (704) the first and second substrate into a low-pressure chamber, pressing the first and second substrate onto each other, the surfaces of the first and second substrate facing each other, wherein, after the pressing, the sealant has been applied around the perimeter of the surface of the first and second substrate outside the sealant barrier thus sealing a low-pressure layer extending between the first and second substrate, wherein the sealant barrier maintains an integrity of the sealant after the sealant is exposed to atmospheric pressure outside the low-pressure chamber.

[0228] After the low-pressure layer has been established, e.g., using method 700, further layers may be applied, including, a temperature regulating layer and / or a light modulator. These further layers do not necessarily need to use a low-pressure chamber, although this is possible.

[0229] The following clauses represent embodiments.

[0230] Clause 1. A glazing unit, the glazing unit comprising a light modulator, the light modulator comprising a first substrate and a second substrate, the first and second substrates being arranged with inner sides opposite to each other, one or more driving electrodes being applied to the inner side of the first substrate, and an optical layer between the first and second substrates, the one or more driving electrodes being configured to cause modulation of optical properties of the optical layer, a liquid-filled, temperature regulating layer, the temperature regulating layer being arranged against the light modulator, outside of the optical layer, and extending across the surface of the first or second substrate, the temperature regulating layer being arranged for cooling and / or heating of the light modulator.

[0231] Clause 2. The glazing unit of Clause 1, wherein the temperature regulating layer is enclosed between two substrates, the two substrates of the temperature regulating layer having a substrate in common with the light modulator.

[0232] Clause 3. The glazing unit of any one of the preceding clauses, further comprising: a controller operatively connected to the temperature regulating layer, the controller being configured to monitor a temperature of the light modulator and adjust a temperature of the liquid in the temperature regulating layer, the controller being configured to maintain the light modulator temperature within a predetermined temperature range by selectively heating or cooling the liquid in the temperature regulating layer.

[0233] Clause 4. The glazing unit of Clause 3, wherein the controller is further configured to adjust the temperature of the liquid in the temperature regulating layer based on at least one of: ambient temperature, incident solar radiation, and desired optical state of the light modulator.

[0234] Clause 5. The glazing unit of any one of the preceding clauses, wherein the temperature regulating layer is configured to heat the light modulator during optical state transitions of the optical layer, thereby accelerating the transition process.

[0235] Clause 6. The glazing unit of any one of the preceding clauses comprising a low-pressure layer, wherein the low-pressure layer is arranged on a side of the light modulator opposite to the temperature regulating layer, wherein the low-pressure layer extends across the surface of the first or second substrate not in contact with the temperature regulating layer, or the low-pressure layer is arranged on a side of the light modulator adjacent to the temperature regulating layer, wherein the low-pressure layer extends across the surface of the temperature regulating layer.

[0236] Clause 7. The glazing unit of any one of the preceding clauses comprising in order: a first glazing substrate, the light modulator, the temperature regulating layer, the low-pressure layer and a second glazing substrate.

[0237] Clause 8. The glazing unit of Clause 6 or 7, wherein multiple spacers are arranged in the optical layer between the first and second substrates, and multiple spacers are arranged in the low-pressure layer, at least part of the multiple spacers arranged in the optical layer being aligned with at least part of the multiple spacers arranged in the low-pressure layer. Clause 9. The glazing unit of any one of the preceding clauses, wherein multiple spacers are arranged in the optical layer between the first and second substrates, and multiple spacers are arranged in the temperature regulating layer, at least part of the multiple spacers arranged in the optical layer being aligned with at least part of the multiple spacers arranged in the temperature regulating layer.

[0238] Clause 10. The glazing unit according to any one of the preceding clauses, wherein the temperature regulating layer has a refractive index within ±0.03 of the refractive index of the first and / or second substrates, preferable within ±0.02, more preferable ±0.01.

[0239] Clause 11. The glazing unit of any one of the preceding clauses, wherein the liquid in the temperature regulating layer comprises at least one of: a glycol-based compound, and a high thermal conductivity liquid, wherein the high thermal conductivity liquid has a thermal conductivity of at least 0.1 W / (m·K) at 25°C, preferably at least 0.2 W / (m K) at 25°C.

[0240] Clause 12. The glazing unit of any one of the preceding clauses, comprising a frame surrounding at least the light modulator and the temperature regulating layer, wherein a heat sink is integrated within the frame and thermally coupled to the temperature regulating layer, the heat sink being configured to dissipate heat from the temperature regulating layer to the surrounding environment, and / or one or more thermoelectric elements integrated within the frame and thermally coupled to the temperature regulating layer, the one or more thermoelectric elements being configured to harvest heat from the temperature regulating layer and convert the harvested heat into electrical energy.

[0241] Clause 13. The glazing unit of any one of the preceding clauses, wherein the light modulator further comprises an anti-reflective coating applied to the temperature regulating layer.

[0242] Clause 14. The glazing unit of any one of the preceding clauses, further comprising a pump operatively connected to the temperature regulating layer and configured to circulate the liquid within the temperature regulating layer to enhance heat transfer. Clause 15. The glazing unit of any one of the preceding clauses, wherein the unit is integrated into a window frame, wherein the window frame comprises a sunshade arranged to shadow one or more edges of the light modulator from the sun.

[0243] Clause 16. The glazing unit of any one of the preceding clauses, wherein the light modulator has multiple segments, the multiple segments being independently, electrically controllable.

[0244] Clause 17. The glazing unit as in the combination of Clause 15 and Clause 16, wherein at least part of the multiple segments have edges along a side of the window frame, the sunshade being arranged to shadow one or more edges along the side of the window frame.

[0245] Clause 18. The glazing unit of any one of the preceding clauses, wherein the temperature regulating layer comprises channels or microchannels through which the liquid flows.

[0246] Clause 19. The glazing unit of any one of the preceding clauses, wherein the temperature regulating layer comprises a valve to circulate liquid in and out of the glazing unit.

[0247] Clause 20. The glazing unit of any one of the preceding clauses, wherein the optical layer comprises a fluid, e.g., a liquid, that comprises particles, wherein the light modulator is configured to apply an electric potential to the one or more driving electrodes causing modulation of an electric field in the optical layer providing electrophoretic and / or dielectrophoretic movement of the particles in the optical layer causing modulation of light passing through the substrates.

[0248] Clause 21. A glazing unit as in any one of the preceding clauses, wherein a thermoelectric material is distributed between the first substrate and / or the second substrate in the optical layer and / or in a low-pressure layer comprised in the glazing unit, the thermoelectric material being configured to generate electricity from heat.

[0249] Clause 22. A glazing unit as in any one of the preceding clauses, comprising a low-pressure layer, enclosed between a first substrate and a second substrate.

[0250] Clause 23. A glazing unit as in any one of the preceding clauses, comprising a first substrate, the first substrate having a sealant barrier applied around a perimeter of a surface of the first substrate, a second substrate having a surface, the first and second substrate being arranged against each other, with a sealant on the surface of the first and second substrate, the surfaces of the first and second substrate facing each other, wherein the sealant is applied around the perimeter of the surface of the first substrate outside the sealant barrier thus sealing a low-pressure layer extending between the first and second substrate.

[0251] Clause 24. A glazing unit of Clause 23, wherein the sealant barrier determines a cell gap between the first and second substrate, or the sealant barrier cooperates with a further sealant barrier on the second substrate, the sealant barrier and further sealant barrier aligning after the pressing and together determining a cell gap between the first and second substrate.

[0252] Clause 25. A glazing unit as in any one of Clauses 22-24 wherein the low-pressure layer reduces heat conduction across the cell gap between the first and second substrate.

[0253] Clause 26. A glazing unit as in any one of Clauses 22-25, wherein the low-pressure layer has a pressure of at most 1 Pa, or at most 0.1 Pa, or at most 0.05 Pa.

[0254] Clause 27. A glazing unit as in any one of Clauses 23-26, wherein the sealant binds the first and second substrate together.

[0255] Clause 28. A glazing unit as in any one of clauses 22-27, wherein further spacers are arranged between the first and second substrates, e.g., wherein photo spacers are arranged across the surface of the first substrate.

[0256] Clause 29. A glazing unit as in any one of Clauses 22-28, wherein the cell gap is at most 50 mm, or at most 1 mm, or at most 0.5 mm, or at most 0.1 mm, or at most 0.01 mm, and / or the cell gap is at least 1 micron and at most 500 micron, preferably, at least 20 micron and at most 100 micron, preferably, at least 20 micron and at most 50 micron, a sealant barrier width is at least 40% and at most 200% of the cell gap, preferably, at least 75% and at most 125% of the cell gap.

[0257] Clause 30. A glazing unit as in any one of Clauses 22-29, wherein the light modulator is arranged in parallel to the low-pressure layer. The light modulator and low-pressure layer may share a substrate.

[0258] Clause 31. A glazing unit as in any one of preceding clauses, wherein the first substrate and / or the second substrate of the light modulator comprise a photovoltaic system or a display.

[0259] Clause 32. A glazing unit as in any one of Clauses 22-31, comprising a further seal applied around the glazing unit and / or the light modulator, for example, wherein the further seal comprises glass solder, and / or the further seal comprises a thermoplastic adhesive, and / or the further seal is obtained by melting together the substrates of the light modulator and the one or more insulating substrate at their perimeters.

[0260] Clause 33. A glazing unit as in any one of the preceding clauses, wherein at least one driving bus is arranged on a substrate of the light modulator for each driving electrode. For example, at least one driving bus is arranged at a side of the substrate for each driving electrode to drive the driving electrode, and / or the driving busses are only arranged at the side of the substrate, and / or

[0261] Clause 34. A glazing unit as in Clause 33, wherein one or more driving electrodes is isolated from the edges of the substrate, a via being connected to the isolated driving electrode from a surface of the substrate opposite the driving electrode for powering the isolated driving electrode and / or connecting the isolated driving electrode to another part of the driving electrode on the substrate.

[0262] Clause 35. A glazing unit as in any one of the preceding clauses, which is non-rectangular. For example, the substrates of the glazing unit may be non-rectangular.

[0263] Clause 36. A glazing unit as in any one of the preceding clauses, wherein the one or more driving electrodes are multiple driving electrodes, the multiple driving electrodes (111-114,121-124) being interdigitated, each of the multiple driving electrodes being arranged in a pattern across the substrate, the multiple interdigitated driving electrodes being arranged alternatingly with respect to each other on the substrate. For example, the pattern of multiple driving electrodes across the substrate may comprise multiple repeated building blocks. For example, the building block may comprise multiple interdigitated electrodes extending in at least 2 directions across the building block, the interdigitated electrodes in the building block forming the driving electrodes.

[0264] Clause 37. A glazing unit as in any one of the preceding clauses, connected or connectable to a controller configured to apply an electric potential to the one or more driving electrodes causing modulation of the optical properties of the light modulator.

[0265] Clause 38. A glazing unit as in any one of the preceding clauses, wherein at least three electrodes are applied to at least one of the first substrate and the second substrate of the light modulator, or at least three electrodes are applied to both the first substrate and the second substrate of the light modulator.

[0266] Clause 39. A glazing unit as in any one of the preceding clauses, wherein a distance between subsequent main-lines of the one or more driving electrodes in the first substrate is larger than a distance between subsequent main-lines of the one or more driving in the second substrate.

[0267] Clause 40. A glazing unit as in any one of the preceding clauses, wherein the light modulator has a transparent state and a non-transparent state, or having a reflective state and a non-reflective state, the light modulator being configured to switch to the non-transparent state or to the non-reflective state by creating an alternating voltage on at least one of the first and second substrates, applying an alternating current between at least a first electrode and a second electrode on the first substrate and / or between a first electrode and a second electrode on the second substrate, switch to the transparent state or to the reflective state by creating an alternating voltage between the first and second substrate, applying an alternating current between a first electrode on the first substrate and a first electrode on the second substrate, and / or between a second electrode on the first substrate and a second electrode on the second substrate.

[0268] Clause 41. A glazing unit as in any of the preceding clauses, comprising at least one current sensing circuit connected to an electrode of the one or more electrodes on a substrate, the current sensing circuit being configured to measure a current in the electrode to which it is connected; the glazing unit being connected to a controller configured to receive at least one current sensing signal from the at least one current sensing circuit indicating a current in the connected electrode, determine driving signals for the one or more driving electrodes from the at least one current sensing signals and from a target transparency or reflectivity, and apply an electric potential to the one or more driving electrodes according to a driving signal to obtain an electric field between the one or more driving electrodes, wherein the electric field provides electrophoretic movement of the particles towards or from one of the one or more driving electrodes.

[0269] Clause 42. A glazing unit as in Clause 41, wherein the driving signal is provided as an alternating current (AC) in the one or more driving electrodes such that a substantially balanced electrolysis current is obtained.

[0270] Clause 43. A glazing unit as in any one of Clauses 41-42, wherein the driving signal is provided as a direct current (DC) in the one or more driving electrodes, wherein the voltage is periodically reversed to such extent that a substantially balanced electrolysis current is obtained.

[0271] Clause 44. A glazing unit as in any one of Clauses 41-43, comprising multiple current sensing circuits, each electrode being connected to a corresponding one of the multiple current sensing circuits.

[0272] Clause 45. A glazing unit as in any one of Clauses 41-44,wherein the controller is configured to determine a transparency or a reflectivity level of the light modulator from the at least one current sensing signals.

[0273] Clause 46. A glazing unit as in any one of the preceding clauses, wherein the one or more driving electrodes comprise multiple interlaced mesh electrodes extending in a two-dimensional pattern across the first substrate and across the second substrate, two mesh electrodes of the multiple mesh electrodes on a substrate crossing at a plurality of crossing points spread across the substrate.

[0274] Clause 47. A glazing unit as in Clause 46 wherein at least two mesh electrodes on a substrate each comprise multiple main lines extending in a first direction across the substrate, the multiple main lines of the at least two mesh electrodes being arranged alternatingly with respect to each other on the substrate, each of the at least two mesh electrodes comprising multiple interconnecting lines electrically connecting the main lines of said mesh electrode together, multiple main lines of the mesh electrode being connected to other main lines of the mesh electrode through multiple interconnections, an interconnecting line crossing with another mesh electrode forming a crossing point.

[0275] Clause 48. A glazing unit as in Clause 47, wherein a number of the main lines in the electrode comprise at least two interconnecting lines, wherein said number is at least two, at least 10, at least half of the number of main lines, at least 90% of the main lines, or substantially all main lines, and / or a main line is connected to at least 2, at least 4, at least 8, or at least 16 interconnection lines, and / or a main line is connected to an interconnection within distance of the edge of the substrate, the distance being less than 10% of the length of the main line.

[0276] Clause 49. A glazing unit as in any one of Clause 46-48, wherein one or more of the main lines and / or interconnecting lines are straight, or are wavy.

[0277] Clause 50. A glazing unit as in any one of the preceding clauses, wherein wherein at least a part of the inner surface area of at least one of the first substrate and the second substrate of the light modulator is provided with a protective coating.

[0278] Clause 51. A glazing unit as in Clause 50, wherein the protective coating is applied to substantially the entire surface of the one or more driving electrodes

[0279] Clause 52. A glazing unit as in any one of the preceding clauses, wherein the light modulator is an electrophoretic modulator. For example, configured for switching between a transparent state and a non-transparent state and vice versa.

[0280] Clause 53. A glazing unit as in any one of the preceding clauses, wherein the light modulator comprises a connection for applying an electric field to the one or more electrodes, wherein the applied electric field to the one or more electrodes provides movement of nano- and microparticles from a first electrode to a second electrode and vice versa, wherein the one or more electrodes comprise an electrical conducting material with a resistivity of less than 100 nS2m at 273 K, wherein the glazing unit is connected to a power provider in electrical connection with the at least two electrodes, wherein the power provider is adapted to provide a waveform AC power, wherein at least one of amplitude, frequency, and phase is adaptable.

[0281] Clause 54. A glazing unit as in any one of the preceding clauses, wherein the one or more driving electrodes comprise at least two electrodes forming an interdigitated pattern. For example, wherein the interdigitated pattern is a regular 2-dimensional pattern. For example, each finger of the interdigitated pattern comprising at least one waveform shape. For example, wherein the waveform shape has an amplitude A and a width W, and wherein fingers are at a distance d from one and another.

[0282] Clause 55. A glazing unit as in any one of the preceding clauses, wherein the one or more driving electrodes are in fluidic contact with the fluid

[0283] Clause 56. A glazing unit as in any one of the preceding clauses, wherein the one or more electrodes cover 1-30% of the substrate surface.

[0284] Clause 57. A glazing unit as in any one of the preceding clauses, wherein a power provider is operated at an AC frequency for switching to a transparent state of 10-100 Hz, and / or a power provider is operated at an AC frequency for switching to a non-transparent state of less than 1 Hz, such as 30-500 mHz, and / or wherein, within one switching cycle, the power provider is operated at an AC frequency for switching to a transparent state of 10-100 Hz, in combination with the power provider initially being operated at a positive or negative voltage when switching to a transparent state and in combination with the power provider being finally operated at a negative or positive voltage when switching to a non-transparent state, and / or wherein the power provider is adapted to provide pulses and to refrain from providing pulses during intervals, and / or wherein the power provider is adapted to provide a variation in amplitude of 5-100% of a maximum amplitude, and / or wherein a balanced electrolysis current is obtained by continuously switching the polarity of oppositely charged electrodes on the first and on the second substrates and / or between the first and the second substrates.

[0285] Clause 58. A glazing unit as in any one of the preceding clauses, wherein optical layer comprises a fluid, which is an apolar fluid with a dielectric constant less than 15, such as branched or unbranched C8-C60 alkanes, branched or unbranched C8-C60 alkenes, branched or unbranched C6-C60 alcohols, branched or unbranched C6-C60 alkanols, branched or unbranched C8-C60 ketones, branched or unbranched C8-C60 aldehydes, silicon oils, and combinations thereof, and / or the dynamic viscosity of the fluid is 500 mPa.s or less, preferably 50 mPa.s or less, such as less than 1 mPa.s, and / or the fluid has a relative permittivity εr of less than 100, preferably less than 10, and / or the fluid comprises counter ions for compensating a charge on the particles, and / or the fluid comprises counter ions for compensating a charge on the particles selected form sulfate, chloride, bromide, and / or combinations thereof, and / or the fluid comprises one or more of a surfactant, an emulsifier, a polar compound, and a compound capable of forming a hydrogen bond.

[0286] Clause 59. A glazing unit as in any one of the preceding clauses, wherein a size of the nanoparticles is from 20-1000 nm, and / or the particles are adapted to absorb or reflect light with a wavelength of 10 nm-1 micron, and / or a coating of the particles is made from a conducting material and / or a semiconducting material, and / or the particles comprise a magnetic material.

[0287] Clause 60. A glazing unit as in any one of the preceding clauses, wherein a distance between the substrates is maintained at a distance of less than 500 µm using one or more spacers, and / or the optical modulator is flexible, the substrate comprising a flexible material, e.g., flexible glass or a flexible polymer, and / or the substrates have a thickness of 0.01 mm - 2 mm, preferably 0.025 mm 1 mm, such as 0.05-0.5 mm.

[0288] Clause 61. A glazing unit as in any one of the preceding clauses, comprising a stack of light modulators, wherein a number of light modulators is from 2-10, preferably 3-5, and wherein optionally at least one substrate (13,14) of a first light modulator is the same as a substrate (13,14) of at least one second light modulator.

[0289] Clause 62. A glazing unit as in any one of the preceding clauses comprising multiple areas, the multiple areas being independently addressed and / or optically switchable, and / or a driver circuit for changing the appearance of individual areas by applying differing electric fields to control one or more appearance selected from haze, contrast, warm / cold effect, complementary contrast, simultaneous contrast, saturation, intensity.

[0290] Clause 63. A light modulator system, the light modulator system comprising a light modulator, the light modulator comprising a first substrate and a second substrate, the first and second substrates being arranged with inner sides opposite to each other, one or more driving electrodes being applied to the inner side of the first substrate, and an optical layer between the first and second substrates, the one or more driving electrodes being configured to cause modulation of optical properties of the optical layer, a liquid-filled, temperature regulating layer, the temperature regulating layer being arranged against the light modulator, outside of the optical layer, and extending across the surface of the first or second substrate, the temperature regulating layer being arranged for cooling and / or heating of the light modulator.

[0291] Clause 64. A light modulator system as in any one of the preceding clauses or part thereof.

[0292] Clause 65. The glazing unit of any one of the preceding Clauses, further comprising a matrix of temperature sensors distributed across the glazing unit, the matrix of temperature sensors being configured to monitor the temperature at multiple locations across the glazing unit. For example, temperature sensors may be integrated in one or more of the optical layer, temperature regulating layer, and insulating layer.

[0293] Clause 66. The glazing unit of Clause 65, wherein the temperature sensors are integrated with spacers within the glazing unit.

[0294] Clause 67. The glazing unit of Clause 65 or 66, wherein the controller is operatively connected to the matrix of temperature sensors and is configured to receive multiple temperature sensor values and use these values to control the temperature regulating layer and / or the light modulator.

[0295] Clause 68. The glazing unit of any one of the preceding Clauses, wherein the glazing unit comprises multiple areas, the optical properties of the multiple areas being independently and electrically controllable.

[0296] Clause 69. The glazing unit of the combination of Clause 65 and Clause 68, wherein the controller is configured to use multiple temperature values from the matrix of temperature sensors to control the optical properties of the multiple areas independently.

[0297] Clause 70. The glazing unit of any one of Clauses 65-69, wherein the controller is configured to use data from the matrix of temperature sensors to detect daily cycles in temperature across the glazing unit and to anticipate these cycles in controlling the temperature regulating layer.

[0298] Clause 71. The glazing unit of any one of the preceding Clauses, comprising a backup energy storage, wherein the controller is configured to initiate cooling via the temperature regulating layer if the temperature detected by the matrix of temperature sensors exceeds a predetermined limit, using energy from the backup energy storage. For example, the backup energy storage may be charged through a thermoelectric element, a photovoltaic element, etc. the backup energy storage may be charged through the electrical grid.

[0299] Clause 72. The glazing unit of any of the preceding Clauses, wherein heating electrodes are arranged on a surface of a substrate of the light modulator system, in particular on a surface facing the temperature regulating layer, and / or a surface facing the optical layer. Heating the glazing unit, e.g., the temperature regulating layer, and / or the optical layer may comprise conducting a current through the heating electrodes. The heating electrodes may form a loop, allowing current to enter and leave the heating electrodes.

[0300] It should be noted that the above-mentioned embodiments illustrate rather than limit the presently disclosed subject matter, and that those skilled in the art will be able to design many alternative embodiments.

[0301] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb 'comprise' and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements. Expressions such as "at least one of' when preceding a list of elements represent a selection of all or of any subset of elements from the list. For example, the expression, "at least one of A, B, and C" should be understood as including only A, only B, only C, both A and B, both A and C, both B and C, or all of A, B, and C. The presently disclosed subject matter may be implemented by hardware comprising several distinct elements, and by a suitably programmed computer. In the device claim enumerating several parts, several of these parts may be embodied by one and 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 advantage.

[0302] In the claims references in parentheses refer to reference signs in drawings of exemplifying embodiments or to formulas of embodiments, thus increasing the intelligibility of the claim. These references shall not be construed as limiting the claim.

Examples

Embodiment Construction

[0011]While the presently disclosed subject matter is susceptible of embodiment in many different forms, there are shown in the drawings and will herein be described in detail one or more specific embodiments, with the understanding that the present disclosure is to be considered as exemplary of the principles of the presently disclosed subject matter and not intended to limit it to the specific embodiments shown and described.

[0012]In the following, for the sake of understanding, elements of embodiments are described in operation. However, it will be apparent that the respective elements are arranged to perform the functions being described as performed by them.

[0013]Further, the subject matter that is presently disclosed is not limited to the embodiments only, but also includes every other combination of features described herein or recited in mutually different dependent claims.

[0014]Figure 1a schematically shows an example of an embodiment of a light modulator system 100 compris...

Claims

1. A glazing unit, the glazing unit comprising - a light modulator, the light modulator comprising - a first substrate and a second substrate, the first and second substrates being arranged with inner sides opposite to each other, one or more driving electrodes being applied to the inner side of the first substrate, and - an optical layer between the first and second substrates, the one or more driving electrodes being configured to cause modulation of optical properties of the optical layer, - a liquid-filled, temperature regulating layer, the temperature regulating layer being arranged against the light modulator, outside of the optical layer, and extending across the surface of the first or second substrate, the temperature regulating layer being arranged for cooling and / or heating of the light modulator.

2. The glazing unit of Claim 1, wherein the temperature regulating layer is enclosed between two substrates, the two substrates of the temperature regulating layer having a substrate in common with the light modulator.

3. The glazing unit of any one of the preceding claims, further comprising: a controller operatively connected to the temperature regulating layer, the controller being configured to monitor a temperature of the light modulator and adjust a temperature of the liquid in the temperature regulating layer, the controller being configured to maintain the light modulator temperature within a predetermined temperature range by selectively heating or cooling the liquid in the temperature regulating layer.

4. The glazing unit of Claim 3, wherein the controller is further configured to adjust the temperature of the liquid in the temperature regulating layer based on at least one of: ambient temperature, incident solar radiation, and desired optical state of the light modulator.

5. The glazing unit of any one of the preceding claims, wherein the temperature regulating layer is configured to heat the light modulator during optical state transitions of the optical layer, thereby accelerating the transition process.

6. The glazing unit of any one of the preceding claims comprising an insulating layer, wherein - the insulating layer is arranged on a side of the light modulator opposite to the temperature regulating layer, wherein the insulating layer extends across the surface of the first or second substrate not in contact with the temperature regulating layer, or - the insulating layer is arranged on a side of the light modulator adjacent to the temperature regulating layer, wherein the insulating layer extends across the surface of the temperature regulating layer.

7. The glazing unit of any one of the preceding claims comprising in order: a first glazing substrate, the light modulator, the temperature regulating layer, the insulating layer and a second glazing substrate.

8. The glazing unit of Claim 6 or 7, wherein the insulating layer is a low-pressure layer.

9. The glazing unit of Claim 8, wherein multiple spacers are arranged in the optical layer between the first and second substrates, and multiple spacers are arranged in the low-pressure layer, at least part of the multiple spacers arranged in the optical layer being aligned with at least part of the multiple spacers arranged in the low-pressure layer.

10. The glazing unit of any one of the preceding claims, wherein multiple spacers are arranged in the optical layer between the first and second substrates, and multiple spacers are arranged in the temperature regulating layer, at least part of the multiple spacers arranged in the optical layer being aligned with at least part of the multiple spacers arranged in the temperature regulating layer.

11. The glazing unit according to any one of the preceding claims, wherein the temperature regulating layer has a refractive index within ±0.03 of the refractive index of the first and / or second substrates, preferable within ±0.02, more preferable ±0.01.

12. The glazing unit of any one of the preceding claims, wherein the liquid in the temperature regulating layer comprises at least one of: - a glycol-based compound, and - a high thermal conductivity liquid, wherein the high thermal conductivity liquid has a thermal conductivity of at least 0.1 W / (m·K) at 25°C, preferably at least 0.2 W / (m·K) at 25°C.

13. The glazing unit of any one of the preceding claims, comprising a frame surrounding at least the light modulator and the temperature regulating layer, wherein - a heat sink is integrated within the frame and thermally coupled to the temperature regulating layer, the heat sink being configured to dissipate heat from the temperature regulating layer to the surrounding environment, and / or - one or more thermoelectric elements integrated within the frame and thermally coupled to the temperature regulating layer, the one or more thermoelectric elements being configured to harvest heat from the temperature regulating layer and convert the harvested heat into electrical energy.

14. The glazing unit of any one of the preceding claims, wherein the light modulator further comprises an anti-reflective coating applied to the temperature regulating layer.

15. The glazing unit of any one of the preceding claims, further comprising a pump operatively connected to the temperature regulating layer and configured to circulate the liquid within the temperature regulating layer to enhance heat transfer.

16. The glazing unit of any one of the preceding claims, wherein the unit is integrated into a window frame, wherein the window frame comprises a sunshade arranged to shadow one or more edges of the light modulator from the sun.

17. The glazing unit of any one of the preceding claims, wherein the light modulator has multiple segments, the multiple segments being independently, electrically controllable.

18. The glazing unit as in the combination of Claim 16 and Claim 17, wherein at least part of the multiple segments have edges along a side of the window frame, the sunshade being arranged to shadow one or more edges along the side of the window frame.

19. The glazing unit of any one of the preceding claims, wherein the temperature regulating layer comprises channels or microchannels through which the liquid flows.

20. The glazing unit of any one of the preceding claims, wherein the temperature regulating layer comprises a valve to circulate liquid in and out of the glazing unit.

21. The glazing unit of any one of the preceding claims, wherein the optical layer comprises a fluid that comprises particles, wherein the light modulator is configured to apply an electric potential to the one or more driving electrodes causing modulation of an electric field in the optical layer providing electrophoretic and / or dielectrophoretic movement of the particles in the optical layer causing modulation of light passing through the substrates.

22. A glazing unit as in any one of the preceding claims, wherein a thermoelectric material is distributed between the first substrate and / or the second substrate in the optical layer and / or in an insulating layer comprised in the glazing unit, the thermoelectric material being configured to generate electricity from heat.

Images