Liquid Crystal Reconfigurable Intelligent Surface Device

Abstract

Apparatus and methods are described for liquid crystal (LC) reconfigurable intelligent surface (RIS) substrate designs and materials. In one example, an LC RIS device includes a first metal layer and a second metal layer, each of which is deposited within a glass substrate. The first metal layer has a first size, and the second metal layer has a second size, the first size and the second size being different. The device further includes an LC layer disposed between the first metal layer and the second metal layer. In one example, the first metal layer includes a plurality of columns, each of which includes a first plurality of LC active layers. In one example, the second metal layer includes a plurality of rows, each of which includes a second plurality of LC active layers.

Description

Description of Related Applications

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Patent Application No. 63 / 405008, filed September 9, 2022, the contents of which are relied upon and incorporated herein by reference in their entirety. [Technical Field]

[0002] The present disclosure relates generally to reconfigurable intelligent surface (RIS) devices, and more particularly to liquid crystal RIS diode devices. [Background technology]

[0003] Millimeter-wave (mm-wave) frequency bands are increasingly being utilized for various applications, such as communications, including 5G and 6G wireless communications. mm-wave communications can offer advantages over previous communications technologies, including faster communication speeds, shorter communication latency, and greater capacity. For example, mm-wave communications can operate in the 30-300 GHz frequency range. However, transmitting and receiving wireless signals within the mm-wave band presents challenges due to, for example, propagation loss, penetration loss, and return loss, which can degrade link performance budgets.

[0004] To address these challenges, some systems utilize high-gain phased-array antennas. However, the additional gain provided by high-gain phased-array antennas can have drawbacks. For example, the antennas can become saturated as the number of array elements increases. Furthermore, high-gain phased-array antennas increase system losses and are gain-limited when utilized in devices with limited space to accommodate the antenna, such as mobile devices.

[0005] More recently, the use of reconfigurable intelligent surface (RIS) devices has been proposed to improve propagation path conditions between base stations and mobile devices in 5G and new radio (NR) communication systems, for example. RISs can involve the use of subwavelength resonators that adaptively reflect, transmit, absorb, and convert the polarization of incident waves, consuming less power. For example, active RISs are millimeter-wave devices that can control signal reflectivity in desired directions. Furthermore, RISs can be manufactured at lower cost due to the generally lower cost components. Summary of the Invention

[0006] Embodiments disclosed herein broadly relate to liquid crystal (LC) reconfigurable intelligent surface (RIS) substrate devices. In some embodiments, the devices can include a layered orthogonal voltage bias structure capable of providing two-dimensional electromagnetic waves. In some embodiments, the devices can provide better control over the active region where LC molecules switch (e.g., tilt) with a bias voltage. For example, the device can include an LC cell including an LC layer, a first electrode, and a second electrode (e.g., a ground electrode), where, based on the design of the LC cell, the LC layer rotates the LC only in the desired active region. Among other advantages, RIS devices can operate more efficiently than conventional devices. Additionally, RIS devices can be utilized in a variety of applications. For example, RIS devices can be utilized in wireless communication systems, such as 5G, NR, and 6G wireless communication systems (e.g., millimeter wave band networks), to provide two-dimensional beamforming, such as beam forwarding and backwarding. Furthermore, the RIS devices can be less expensive to manufacture than conventional RIS devices. Those skilled in the art with the benefit of these disclosures will recognize other benefits as well.

[0007] In one example, a unit cell device includes parallel metal layers deposited within a glass material and an LC layer disposed between the metal layers. The metal layers may be in a repeating pattern (e.g., a repeating array). The unit cell device can resonate near an operating frequency band. The metal layers can be used as bias voltage lines, where the alignment of the LCs within the LC layer is achieved by the bias voltage between the metal layers. Therefore, the LC alignment can be changed based on the bias voltage, resulting in a variation in the dielectric constant (e.g., epsilon), which can range from 1 to 100 for the LC material. This variable epsilon can enable a variety of frequency responses for the unit cell device.

[0008] For example, the unit cell device can include a first metal layer (e.g., a top metal layer) laterally offset from a second metal layer (e.g., a bottom metal layer), where the first metal layer and the second metal layer are deposited within a glass material. The first metal layer can include columns, each column including a first plurality of LC active layers. Further, the columns can be electrically disconnected from one another. For example, each of the columns can be electrically connected to a power source (e.g., a bias power source). The second metal layer can include rows, each row including a second plurality of LC active layers. Each row can be electrically disconnected from every other row. In one example, each of the first plurality of LC active layers is laterally offset from a corresponding one of the second plurality of LC active layers. The unit cell device also includes an LC layer between the first metal layer and the second metal layer.

[0009] In some examples, the rows of the second metal layer are electrically connected to a ground (e.g., a common ground). In other examples, the rows of the second metal layer are electrically connected to a power supply.

[0010] In one example, the columns of the first metal layer are electrically connected to ground while the rows of the second metal layer are electrically connected to a power supply. In another example, the columns of the first metal layer are electrically connected to a power supply while the rows of the second metal layer are electrically connected to ground. In yet another example, each of the columns of the first metal layer and the rows of the second metal layer are electrically connected to a power supply.

[0011] In one example, the unit cell device includes parallel metal layers deposited within a glass material and a liquid crystal (LC) layer disposed between the metal layers. Each of the parallel metal layers can function as an electrode. For example, the parallel metal layers can include a first metal layer and a second metal layer, where the first metal layer is electrically connected to a power source and the second metal layer is electrically connected to ground. In one example, the first metal layer and the second metal layer have the same size. For example, the first metal layer and the second metal layer can have the same width and length (e.g., in a rectangular example). In one example, the first metal layer has a larger size than the second metal layer. For example, the first metal layer can have an area that is a certain percentage (e.g., 10%) larger than the second metal layer. In another example, the first metal layer has a smaller size than the second metal layer. For example, the first metal layer can have an area that is a certain percentage (e.g., 10%) smaller than the second metal layer. In one example, the first metal layer can have the same size as the glass material, while the second metal layer has a smaller size than the glass material.

[0012] In some embodiments, the unit cell device includes a first metal layer and a second metal layer, each of the first metal layer and the second metal layer being deposited within a glass material, the first metal layer having a first size, the second metal layer having a second size, the first size and the second size being different, and an LC layer disposed between the first metal layer and the second metal layer.

[0013] In some embodiments, the unit cell device includes a first metal layer and a second metal layer deposited within a glass substrate, the first metal layer being laterally offset from the second metal layer. The first metal layer includes a plurality of columns, each of the plurality of columns including a first plurality of LC active layers. The second metal layer includes a plurality of rows, each of the plurality of rows including a second plurality of LC active layers. The unit cell device further includes an LC layer deposited between the first metal layer and the second metal layer.

[0014] In one example, a method, such as by an apparatus with one or more processors executing instructions, includes depositing a metal material on a first glass substrate to form a first metal layer having a first size. The method can also include depositing an LC material on the first metal layer to form an LC layer. Further, the method can also include depositing a metal material on the LC layer to form a second metal layer having a second size different from the first size. The method can also include depositing a second glass substrate on the second metal layer.

[0015] In one example, a method, such as by an apparatus with one or more processors executing instructions, includes depositing a metal material on a first glass substrate to form a first metal layer including a first plurality of LC active layers. The method can also include depositing an LC material on the first metal layer to form an LC layer. Further, the method can also include depositing a metal material on the LC layer to form a second metal layer including a second plurality of LC active layers. The method can also include depositing a second glass substrate on the second metal layer.

[0016] In some embodiments, a non-transitory computer-readable medium stores instructions that, when executed by one or more processors, cause an apparatus to perform a method including depositing a metal material on a first glass substrate to form a first metal layer having a first size. The method can also include depositing an LC layer on the first metal layer to form an LC layer. Further, the method can also include depositing a metal material on the LC layer to form a second metal layer having a second size different from the first size. The method can also include depositing a second glass substrate on the second metal layer.

[0017] In some embodiments, a non-transitory computer-readable medium stores instructions that, when executed by one or more processors, cause an apparatus to perform a method including depositing a metal material on a first glass substrate to form a first metal layer including a first plurality of LC active layers. The method can also include depositing an LC material on the first metal layer to form an LC layer. Further, the method can also include depositing a metal material on the LC layer to form a second metal layer including a second plurality of LC active layers. The method can also include depositing a second glass substrate on the second metal layer. [Brief explanation of the drawings]

[0018] The foregoing summary and the following detailed description of illustrative embodiments may be read in conjunction with the accompanying drawings, which illustrate some of the illustrative embodiments described herein. As explained further below, the claims are not limited to the illustrative embodiments. For clarity and readability, the drawings may omit the illustration of certain features. [Figure 1A] Diagram showing some example devices [Figure 1B] Diagram showing some example devices [Figure 2A] Figure 1 shows alignment of liquid crystals in a device according to some examples. [Figure 2B]Figure 1 shows alignment of liquid crystals in a device according to some examples. [Figure 2C] Figure 1 shows alignment of liquid crystals in a device according to some examples. [Figure 3] Phase and permittivity chart with some examples [Figure 4A] Diagram showing some example devices [Figure 4B] FIG. 4B illustrates a frequency response corresponding to the device of FIG. 4A, according to some examples. [Figure 5A] Diagram showing some example devices [Figure 5B] FIG. 5B illustrates a frequency response corresponding to the device of FIG. 5A, according to some examples. [Figure 6A] Diagram showing some example devices [Figure 6B] FIG. 6B illustrates a frequency response corresponding to the device of FIG. 6A according to some examples. [Figure 7A] Diagram showing some example devices [Figure 7B] FIG. 7B illustrates a frequency response corresponding to the device of FIG. 7A, according to some examples. [Figure 8A] Figure 1 shows the electric field distribution of some example devices. [Figure 8B] 1 illustrates switching of liquid crystals in devices according to some examples. [Figure 9A] Diagram showing some example devices [Figure 9B] Diagram showing some example devices [Figure 9C] Diagram showing some example device configurations [Figure 9D] Diagram showing some example device configurations [Figure 9E] Diagram showing some example device configurations [Figure 9F] Diagram showing some example device configurations [Figure 10A] Diagram showing some example devices [Figure 10B] Diagram showing some example tilt angles [Figure 10C] Diagram showing some example tilt angles [Figure 11A] Diagram showing devices in some example configurations [Figure 11B] Diagram showing devices in some example configurations [Figure 11C] Diagram showing devices in some example configurations [Figure 11D] Diagram showing devices in some example configurations [Figure 11E] FIG. 11B illustrates the tilt angles of the devices of FIGS. 11A, 11B, 11C, and 11D according to some examples. [Figure 12A] Diagram showing devices in some example configurations [Figure 12B] Diagram showing devices in some example configurations [Figure 12C] Diagram showing devices in some example configurations [Figure 13A] Diagram showing some example devices [Figure 13B] Diagram showing some example devices DETAILED DESCRIPTION OF THE INVENTION

[0019] This application discloses illustrative (i.e., example) embodiments. The disclosure is not limited to the illustrative embodiments. Accordingly, many implementations of the claims will vary from the illustrative embodiments. Various modifications can be made to the claims without departing from the spirit and scope of the disclosure. The claims are intended to cover implementations with such modifications.

[0020] At times, directional terms (e.g., front, back, top, bottom, left, right, etc.) may be used in this application to provide context for the reader when viewing the drawings. However, the claims are not limited to the orientation shown in the drawings. Any absolute terms (e.g., high, low, etc.) may be understood to disclose the corresponding relative terms (e.g., higher, lower, etc.). Additionally, although the illustrative examples set forth herein may refer to a reconfigurable intelligent surface (RIS) device with a liquid crystal (LC) layer, the illustrative embodiments may also include other types of suitable semiconductor devices.

[0021] 1A and 1B illustrate a RIS device 100, such as an LC RIS unit cell. The RIS device 100 includes a first glass substrate 102, a second glass substrate 104, a first metal layer 110, a second metal layer 120, and an LC layer 130. The first metal layer 110 includes a plurality of metal columns 112, each including a first plurality of LC active layers 114. Similarly, the second metal layer 120 includes a plurality of metal rows 122, each including a second plurality of LC active layers 124. The first metal layer 110 is laterally offset (i.e., a cell gap) from the second metal layer 120. In some examples, the cell gap is in the range of 3 to 500 micrometers. In some examples, the cell gap is in the range of 10 to 200 micrometers. In some examples, the cell gap is in the range of 5 to 200 micrometers. For example, the first metal layer 110 may be laterally offset from and parallel to the second metal layer 120. Additionally, the LC layer 130 may be comprised of an LC material deposited between the first metal layer 110 and the second metal layer 120. Examples of LC materials may include dual frequency LC, cholesteric LC, smectic LC, blue phase LC, ferroelectric LC, nematic LC, discotic LC, thermotropic LC, and lyotropic LC.

[0022] As shown, each of the first plurality of LC active layers 114 may be laterally offset from a corresponding one of the second plurality of LC active layers 124. LC material from LC layer 130 is deposited between each of the first plurality of LC active layers 114 and a corresponding one of the second plurality of LC active layers 124. Additionally, each of the first plurality of LC active layers 114 and a corresponding one of the second plurality of LC active layers 124 may function as an electrode and provide a bias voltage to the LC material deposited therebetween.

[0023] For example, each of the plurality of metal columns 112 of the first metal layer 110 can be electrically connected to a power source (e.g., a DC bias line) to supply a voltage to each of the first plurality of LC active layers 114. In some examples, each of the plurality of metal columns 112 is electrically connected to the same power source. In some examples, at least two of the plurality of metal columns 112 are electrically connected to different power sources. Therefore, each of the plurality of metal columns 112 can supply the same or different voltages to each of the corresponding first plurality of LC active layers 114.

[0024] Similarly, each of the plurality of metal rows 122 of the second metal layer 120 may be electrically connected to a power source or to ground. In some examples, each of the plurality of metal rows 122 is electrically connected to the same power source or ground. In some examples, at least two of the plurality of metal rows 122 are electrically connected to different power sources. Therefore, each of the plurality of metal rows 122 can supply the same or different voltages to each of the corresponding second plurality of LC active layers 124.

[0025] The metal columns 112 of the first metal layer 110 and the metal rows 122 of the second metal layer 120 provide orthogonal bias voltage lines to corresponding portions of the LC layer 130. Therefore, each of the first plurality of LC active layers 114 and a corresponding one of the second plurality of LC active layers 124 can form an LC active area therebetween. For example, each of the first plurality of LC active layers 114 and a corresponding one of the second plurality of LC active layers 124 can provide a bias voltage to the LC material therebetween, thereby shifting the corresponding LC. By providing different voltages to the metal columns 112 of the first metal layer 110 and the metal rows 122 of the second metal layer 120, a single RIS 100 can provide various voltage differences between each of the first plurality of LC active layers 114 and a corresponding one of the second plurality of LC active layers 124.

[0026] In one application, by providing a varying voltage difference between each of the first plurality of LC active layers 114 and a corresponding one of the second plurality of LC active layers 124, RIS device 100 can provide two-dimensional beamforming in a wireless communication system, such as a 5G, NR, or 6G wireless communication system. Furthermore, although RIS device 100 is generally depicted as a rectangular unit cell, RIS device 100 may have any suitable shape, such as a circular, elliptical, pentagonal, hexagonal, etc. Furthermore, as shown in FIG. 1B, RIS device 100 may optionally include a third metal layer 140 electrically connected to ground.

[0027] 2A, 2B, and 2C illustrate three modes of operation in which a bias voltage-based LC shift alignment is imparted across one of the first plurality of LC active layers 114 and a corresponding one of the second plurality of LC active layers 124. The alignment shift results in a change in the dielectric constant of the LC. In this example, a power supply 204 is electrically connected to each of the LC active layers 114, 124, thereby providing a bias voltage across the LC layer 130. In FIG. 2A, no voltage is applied (e.g., the power supply 204 is off), and therefore the LC 201 is parallel to the LC active layers 114, 124 (e.g., zero tilt). In FIG. 2B, the power supply 204 is turned on, providing a first voltage across the LC active layers 114, 124. In response, at least some of the LC 201 tilt (e.g., to a corresponding first angle). 2C, the voltage provided by the power supply 204 is increased to provide a second voltage across the LC active layers 114, 124. In response, at least some of the LCs 201 tilt further (e.g., to a corresponding second angle greater than the first angle). In some cases, the distance from one of the first plurality of LC active layers 114 to a corresponding one of the second plurality of LC active layers 124 (as shown as "h" in FIG. 2C) can be in the range of 10 to 200 micrometers. In some examples, the distance can be in the range of 10 to 200 micrometers. In some examples, the distance can be in the range of 5 to 200 micrometers.

[0028] FIG. 3 includes a chart 300 showing approximated epsilon 302, calculated epsilon 304, approximated phase 306, and calculated phase 308 for a bias voltage 310, such as the bias voltage provided by the LC active layers 114, 124 of FIGS. 2A, 2B, and 2C. The calculated epsilon values ​​indicate the effective epsilon of the LC calculated by a numerical method based on its molecular structure while varying the bias voltage. The approximated values ​​show how the calculated epsilon values ​​change as a function of bias voltage. Generally, as the bias voltage 310 increases, the approximated and calculated epsilons 302, 304 increase, while the approximated and calculated phases 306, 308 decrease. As can be seen from chart 300, at higher bias voltages 310 (e.g., above 25 V), the approximated and calculated epsilons 302, 304 increase at a slower rate than at lower bias voltages 310 (e.g., below 25 V). Similarly, the approximate and calculated phases 306, 308 decrease at a lower rate at higher bias voltages 310 than at lower bias voltages 310.

[0029] 4A illustrates a RIS device 400 including a first glass substrate 402, a second glass substrate 404, a first metal layer 410, a second metal layer 420, and an LC layer 430. The first metal layer 410 includes a plurality of metal columns 412, each including a first plurality of LC active layers 414. Similarly, the second metal layer 420 includes a plurality of metal rows 422, each including a second plurality of LC active layers 424. While five metal columns 412 and five metal rows 422 are shown, the RIS device 400 may have any suitable number of metal columns 412 (e.g., 1, 3, 7, 10, etc.) and any suitable number of metal rows 422 (e.g., 1, 3, 7, 10, etc.). In some examples, the number of metal columns 412 and the number of metal rows 422 are the same. In some examples, the number of metal columns 412 and the number of metal rows 422 are different.

[0030] 4A, the first metal layer 410 is laterally offset from the second metal layer 420. For example, the first metal layer 410 may be laterally offset from and parallel to the second metal layer 420. Additionally, the LC layer 430 may be comprised of an LC material deposited between the first metal layer 410 and the second metal layer 420.

[0031] In this example, each of the multiple metal columns 412 in the first metal layer 410 is electrically connected to a corresponding power supply 415. For example, the first metal column 412A is electrically connected to the first power supply 415A. Furthermore, the second metal column 412B is electrically connected to the second power supply 415B, the third metal column 412C is electrically connected to the third power supply 415C, the fourth metal column 412D is electrically connected to the fourth power supply 415D, and the fifth metal column 412E is electrically connected to the fifth power supply 415E. Each of the power supplies 415A, 415B, 415C, 415D, and 415E can supply the same or different voltages as the others. Furthermore, in this example, each of the multiple metal rows 422 in the second metal layer 420 is electrically connected to ground 417. Therefore, each of the first plurality of LC active layers 414 and a corresponding one of the second plurality of LC active layers 424 supplies a bias voltage across a corresponding portion (e.g., LC active area) of the LC layer 430, where the bias voltage may vary across the plurality of metal columns 412 of the first metal layer 410.

[0032] FIG. 4B shows a diagram 450 identifying frequency responses corresponding to each of the plurality of metal columns 412 of the first metal layer 410. For example, assume that each of the power supplies 415A, 415B, 415C, 415D, and 415E provides a corresponding voltage that is different from the others. Therefore, the first metal column 412A can enable a first frequency response 452A, the second metal column 412B can enable a second frequency response 452B, and the third metal column 412C can enable a third frequency response 452C, the fourth metal column 412D can enable a fourth frequency response 452D, and the fifth metal column 412E can enable a fifth frequency response 452E. Therefore, the RIS device 400 can provide different frequency responses across the plurality of metal columns 412 (e.g., different frequency responses along the “Y” direction of the RIS device 400).

[0033] 5A illustrates a RIS device 400 having different bias voltages across multiple metal rows 422 in the second metal layer 420. In this example, each of the multiple metal columns 412 in the first metal layer 410 is electrically connected to ground 417. However, the multiple metal rows 422 in the second metal layer 420 are electrically connected to corresponding power supplies 415. For example, the first metal row 422A is electrically connected to a first power supply 415A. Furthermore, the second metal row 422B is electrically connected to a second power supply 415B, the third metal row 422C is electrically connected to a third power supply 415C, the fourth metal row 422D is electrically connected to a fourth power supply 415D, and the fifth metal row 422E is electrically connected to a fifth power supply 415E. Each of the power supplies 415A, 415B, 415C, 415D, and 415E can supply the same or a different voltage than the others. Therefore, each of the first plurality of LC active layers 414 and a corresponding one of the second plurality of LC active layers 424 supplies a bias voltage across a corresponding portion (e.g., LC active area) of the LC layer 430, where the bias voltage may vary across the plurality of metal rows 422 of the second metal layer 420.

[0034] FIG. 5B shows a diagram 460 identifying frequency responses corresponding to each of the multiple metal rows 422 of the second metal layer 420. For example, assume that each of the power supplies 415A, 415B, 415C, 415D, and 415E provides a corresponding voltage that is different from the others. Therefore, the first metal row 422A can enable a first frequency response 462A, and the second metal row 422B can enable a second frequency response 462B. Furthermore, the third metal row 422C can enable a third frequency response 462C, the fourth metal row 422D can enable a fourth frequency response 462D, and the fifth metal row 422E can enable a fifth frequency response 462E. Therefore, the RIS device 400 can provide different frequency responses across the multiple metal rows 422 (e.g., different frequency responses along the “X” direction of the RIS device 400).

[0035] 6A illustrates a RIS device 400 in which bias voltages are different between the plurality of metal columns 412 in the first metal layer 410 and the plurality of metal rows 422 in the second metal layer 420. Specifically, in this example, the plurality of metal rows 422 in the second metal layer 420 are electrically connected to corresponding power supplies 415, as shown in FIG. 5A. Furthermore, each of the plurality of metal columns 412 in the first metal layer 410 is electrically connected to a corresponding power supply 475. For example, the first metal column 412A is electrically connected to a sixth power supply 475A. Furthermore, the second metal column 412B is electrically connected to a seventh power supply 475B, the third metal column 412C is electrically connected to an eighth power supply 475C, the fourth metal column 412D is electrically connected to a ninth power supply 475D, and the fifth metal column 412E is electrically connected to a tenth power supply 475E. Each of the power supplies 415A, 415B, 415C, 415D, 415E, 475A, 475B, 475C, 475D, and 475E can supply the same or a different voltage than the others.

[0036] Thus, each of the first plurality of LC active layers 414 and a corresponding one of the second plurality of LC active layers 424 provides a bias voltage across a corresponding portion (e.g., LC active area) of the LC layer 430, where the bias voltage may vary across the plurality of metal columns 412 of the first metal layer 410 and the plurality of metal rows 422 of the second metal layer 420. For example, each of the first plurality of LC active layers 414 and a corresponding one of the second plurality of LC active layers 424 may provide a bias voltage across the corresponding portion of the LC layer 430, thereby enabling a frequency response that may differ from the frequency response enabled by others of the first plurality of LC active layers 414 and corresponding ones of the second plurality of LC active layers 424. In some examples, the same bias voltage may be provided between two or more of the first plurality of LC active layers 414 and corresponding ones of the second plurality of LC active layers 424. In one example, each of the first plurality of LC active layers 414 and a corresponding one of the second plurality of LC active layers 424 is provided with a different bias voltage than the others.

[0037] 6B shows a diagram 470 identifying the frequency responses corresponding to each of the first plurality of LC active layers 414 and a corresponding one of the second plurality of LC active layers 424. For example, in this example, up to 25 different frequency responses may be provided by the RIS device 400. Thus, in this example, the RIS device 400 may provide different frequency responses across the multiple metal columns 412 (e.g., different frequency responses along the "Y" direction of the RIS device 400) as well as different frequency responses across the multiple metal rows 422 (e.g., different frequency responses along the "X" direction of the RIS device 400).

[0038] 7A and 7B show a RIS device 700 including a first glass substrate 702, a second glass substrate 704, a first metal layer 709, a second metal layer 719, and an LC layer 730. The first metal layer 709 includes a first metal column 710 and a second metal column 712. Similarly, the second metal layer 719 includes a first metal row 720 and a second metal row 722. The first metal layer 709 is laterally offset from the second metal layer 719. For example, the first metal layer 709 may be laterally offset from and parallel to the second metal layer 719. Furthermore, the LC layer 730 may consist of an LC layer deposited between the first metal layer 709 and the second metal layer 719.

[0039] In this example, a first power supply 715A is electrically connected to a first metal column 710 of a first metal layer 709, and a second power supply 715B is electrically connected to a second metal column 712 of the first metal layer 709. Similarly, a third power supply 725A is electrically connected to a first metal row 720 of a second metal layer 719, and a fourth power supply 725B is electrically connected to a second metal row 722 of the second metal layer 719.

[0040] RIS device 700, in this example, can provide up to four bias voltages across corresponding portions of LC layer 730. For example, a first bias voltage can be provided between first metal column 710 of first metal layer 709 and first metal row 720 of second metal layer 719 (e.g., based on voltages provided by power supplies 715A and 725A). Additionally, a second bias voltage can be provided between first metal column 710 of first metal layer 709 and second metal row 722 of second metal layer 719 (e.g., based on voltages provided by power supplies 715A and 725B). Similarly, a third bias voltage can be provided between second metal column 712 of first metal layer 709 and first metal row 720 of second metal layer 719 (e.g., based on voltages provided by power supplies 715B and 725A). Additionally, a fourth bias voltage can be provided between second metal column 712 of first metal layer 709 and second metal row 722 of second metal layer 719 (e.g., based on the voltages provided by power supplies 715B and 725B). Thus, RIS device 700 can provide up to four different frequency responses based on four bias voltages in this example.

[0041] As can be seen, each of the first metal column 710, second metal column 712, first metal row 720, and second metal row 722 is electrically connected to a corresponding power supply, although in some examples, one or more of the first metal column 710, second metal column 712, first metal row 720, and second metal row 722 are electrically connected to ground. Additionally, as shown in FIG. 7B, the RIS device 700 can optionally include a third metal layer 740 electrically connected to ground.

[0042] 8A and 8B show that the LC aligns (e.g., tilts) when under a bias voltage and located in an "active area" (e.g., an LC switching area), but does not align when not located in the "active area." Active RIS devices may include a frequency selective surface (FSS) layer and an LC layer for phase adjustment. The FSS layer reflects a desired frequency band, and the LC layer can be used to control beam steering. In some embodiments, the LC in the LC layer rotates in the unit cell of the FSS area of ​​the RIS device based on the design of the ground electrode of the LC unit cell.

[0043] For example, FIG. 8A is an image 800 showing the electric field distribution on a passive frequency selective surface (FSS) device 802 under radio frequency (RF) wave incidence. This electric field distribution appears across most of the unit cell 804 of the passive FSS device 802. FIG. 8B shows a RIS device 850 with a glass substrate 852, a unit cell 854 (e.g., to which a voltage can be applied by electrodes), and LCs 860 and 862. The LC 862 is within the LC active area of ​​the unit cell 854, while the LC 860 is not. The first drawing (i.e., the drawing on the left) shows the RIS device 850 with the bias voltage in the “off” state (e.g., no voltage applied), while the second drawing (i.e., the drawing on the right) shows the RIS device 850 with the bias voltage in the “on” state (e.g., voltage applied). As can be seen, LC 862 is in an unaligned state when the bias voltage is "off" and is in an aligned state when the bias voltage is "on." However, LC 860 remains in an unaligned state regardless of whether the bias voltage is "on" or "off."

[0044] 9A and 9B illustrate a device 900 (e.g., an LC unit cell), with FIG. 9A showing a three-dimensional view of device 900 and FIG. 9B showing a side view thereof. Device 900 includes a first bias voltage electrode 902, a second bias voltage electrode 904, and an LC layer 910 disposed between the first electrode 902 and the second electrode 904. Device 900 may further include a first glass substrate 920 (e.g., a top glass substrate) and a second glass substrate 922 (e.g., a bottom glass substrate), as shown in FIG. 9B. The first glass substrate 920 and the second glass substrate 922 can surround (e.g., enclose) the first electrode 902 and the second electrode 904. In some examples, the sizes (e.g., areas) of the first electrode 902 and the second electrode 904 can be the same or substantially the same (e.g., within 1%). In some examples, the first electrode 902 and the second electrode 904 may be different sizes.

[0045] For example, Figures 9C, 9D, 9E, and 9F show various configurations of device 900. In Figure 9C, the second electrode 904 is the same size (or substantially the same size) as the second glass substrate 922. In this example, the first electrode 902 may be smaller than or substantially the same size as the second electrode 904.

[0046] 9D , the second electrode 904 has a larger size than the first electrode 902. For example, the second electrode 904 may have a size that is 10% larger than the first electrode 902. In some examples, the second electrode 904 may have a size that is in the range of 5% to 25% larger than the first electrode 902. In some examples, the second electrode 904 may have a size that is in the range of 25% to 50% larger than the first electrode 902. Furthermore, the second electrode 904 may have a size that is the same as or smaller than the size of the first electrode 902.

[0047] 9E, the second electrode 904 has the same or substantially the same size as the first electrode 902. In addition, the second electrode 904 and the first electrode 902 each have a size that is the same as or smaller than the size of the second glass substrate 922. In one example, the second electrode 904 and the first electrode 902 each have a size in the range of 30% to 70% of the size of the second glass substrate 922.

[0048] 9F , the second electrode 904 has a smaller size than the first electrode 902. For example, the second electrode 904 may have a size that is 10% smaller than the first electrode 902. In some examples, the second electrode 904 may have a size that is 5% to 25% smaller than the first electrode 902. In some examples, the second electrode 904 may have a size that is 25% to 50% smaller than the first electrode 902. Furthermore, the first electrode 902 may have a size that is the same as or smaller than the size of the second glass substrate 922.

[0049] 9C, 9D, 9E, and 9F, the first glass substrate 920 may be the same or substantially the same size as the second glass substrate 922. Additionally, although the device 900 is shown as a cube, other shapes and forms are contemplated, such as a rectangle, a prism, a sphere, a pyramid, and a cylinder.

[0050] When a bias voltage is applied between the first electrode 902 and the second electrode 904 (e.g., for any of the configurations of Figures 9C, 9D, 9E, and 9F), at least some of the LCs in the LC layer 910 shift to an aligned state. For example, Figure 10B shows a tilt angle 1006 of LC 1004. Initially, with no bias voltage applied, the LC may have a tilt angle of, for example, 2 degrees. Once a bias voltage is applied, some LCs, such as LC 1004, may "tilt" from an initial position (e.g., 2 degrees) to a final position (e.g., 90 degrees). The tilted LCs will depend on the configuration of device 900.

[0051] For example, Figure 10A shows a cross-sectional view 1002 of device 900, and Figure 10C shows a chart 1010 identifying the tilt angles of the LC within the portion of the LC layer 910 identified at the cross-sectional view 1002 in various device 900 configurations corresponding to Figures 9C, 9D, 9E, and 9F. The tilt angles correspond to the LC from an initial position 950 at the cross-sectional view 1002 to a final position 952 at the cross-sectional view 1002. Chart 1010 shows that the device 900 configuration of Figure 9F, in which the second electrode 904 has a smaller size (e.g., 10% smaller) than the first electrode 902, does not tilt the LC outside the area of ​​the first electrode 902 as much as the other device 900 configurations.

[0052] 11A, 11B, 11C, and 11D show a device 1100 configured as described with respect to FIGS. 9C, 9D, 9E, and 9F, respectively. Each of FIGS. 11A, 11B, 11C, and 11D further shows an LC 1101 (e.g., a portion of the LC layer between the electrodes) within the active area 1102 of the device 1100, as well as an LC 1105 outside the active area 1102. FIG. 11A shows the LC active area 1102 of the device 1100 when in the configuration described with respect to FIG. 9C (e.g., the second electrode 904 is the same or substantially the same size as the second glass substrate 922 and is larger than the first electrode 902). FIG. 11B shows the LC active area 1102 of the device 1100 when in the configuration described with respect to FIG. 9D (e.g., the second electrode 904 has a size larger (e.g., 10%) than the first electrode 902). Figure 11C shows the LC active area 1102 of the device 1100 when in the configuration described with respect to Figure 9E (e.g., the second electrode 904 has the same or substantially the same size as the first electrode 902). Additionally, Figure 11D shows the LC active area 1102 of the device 1100 when in the configuration described with respect to Figure 9F (e.g., the second electrode 904 has a smaller (e.g., 10%) size than the first electrode 902).

[0053] 11A, 11B, and 11C further show areas 1120 of LCs 1105 where corresponding LCs 1105 align outside of their respective LC active areas 1102 when the corresponding LC active areas 1102 are under a bias voltage. For example, when a bias voltage is applied to the LC active areas 1102 in FIG. 11A (when the device 1100 is in the configuration of FIG. 9C ), the LCs 1105 in the areas 1120 tend to tilt (e.g., their tilt angles increase from their initial angles). Similarly, FIGS. 11B and 11C also identify the LCs 1105 in the areas 1120 that tend to tilt when a bias voltage is applied in the corresponding configuration. However, in FIG. 11D , none of the LCs 1105 outside the LC active areas 1102 tend to tilt when a bias voltage is applied. Instead, only the LCs 1101 within the LC active areas 1102 tend to tilt when a bias voltage is applied.

[0054] 11E shows a chart 1150 illustrating the tilt angles in the central region of the corresponding LC active area 1102 of device 1100 for various bias voltages in each of the configurations of FIGS. 11A, 11B, 11C, and 11D. As can be seen, there is no significant difference in these tilt angles between the various electrode configurations (e.g., the various ground electrode configurations of FIGS. 9C, 9D, 9E, and 9F).

[0055] FIG. 12A shows a device 1200 (e.g., an LC unit cell) including a first voltage source 1202 (e.g., a bias electrode), a second electrode 1204 (e.g., a ground electrode), and an LC layer 1210 disposed between the first electrode 1202 and the second electrode 1204. The device 1200 further includes a first glass substrate 1206 (e.g., a top glass substrate) and a second glass substrate 1208 (e.g., a bottom glass substrate). The first glass substrate 1206 and the second glass substrate 1208 can surround (e.g., enclose) the first electrode 1202 and the second electrode 1204. In this example, the first electrode 1202 and the second electrode 1204 are different in size, as described herein. The size of the second electrode 1204, which may be, for example, a ground electrode, can be smaller than the size of the first electrode 1202. FIG. 12A also shows the LC active area 1215, which includes the portion of the LC layer 1210 disposed between an area of ​​the first electrode 1202 and an area of ​​the second electrode 1204.

[0056] 12A and 12B show two types of LC configurations for a device 1200. For example, FIG. 12B shows a left view and a right view. Each of these views shows a device 1200 with an LC 1212 outside the LC active area 1215 and an LC 1214 inside the LC active area 1215. In the left view, no voltage is applied across the LC layer 1210. Therefore, in this example, the LC 1212 and LC 1214 are initially in a homogeneous orientation (e.g., parallel to the first glass substrate 1206 and the second glass substrate 1208). In the right view, a power supply 1220 is electrically connected to the first electrode 1202 and the second electrode 1204. In this example, the electrical connection from the power supply 1220 to the second electrode 1204 is a ground connection. The power supply 1220 can provide a bias voltage across the LC active area 1215. In this example, when the power supply 1220 is turned on, the LC 1214 tilts 90 degrees (e.g., becomes perpendicular to the first glass substrate 1206 and the second glass substrate 1208). However, the LC 1212 does not tilt, at least because the second electrode 1204 has a size smaller than the size of the first electrode 1202.

[0057] FIG. 12C also shows a left and right view. Each of these views also shows a device 1200 with an LC 1212 outside the LC active area 1215 and an LC 1214 within the LC active area 1215. In the left view, no voltage is applied across the LC layer 1210. However, in this example, the LC 1212 and LC 1214 are initially in a homeotropic alignment (e.g., perpendicular to the first glass substrate 1206 and the second glass substrate 1208). In the right view, a power supply 1220 is electrically connected to the first electrode 1202 and the second electrode 1204, and the electrical connection from the power supply 1220 to the second electrode 1204 is a ground connection. The power supply 1220 can provide a bias voltage across the LC active area 1215. In this example, when the power supply 1220 is turned on, the LC 1214 tilts 90 degrees (e.g., becomes parallel to the first glass substrate 1206 and the second glass substrate 1208). However, the LC 1212 does not tilt, at least because the second electrode 1204 has a size smaller than the size of the first electrode 1202.

[0058] Under certain circumstances, when transparent active RIS devices are exposed to sunlight (e.g., over extended periods of time), material degradation can cause reliability issues. For mm-wave applications, LC molecules with long side chains specifically designed for large retardation in the mm-wave band can be utilized. These long side chains in the molecules can be affected by extended exposure to external light, such as sunlight. As a result of exposure, the switching characteristics of these devices are affected. For example, the switching characteristics can deteriorate, causing the color of the device (e.g., when used in LCD applications) to change. To protect against these potential light exposures, the embodiments described herein can include one or more of a light filter substrate and a light-absorbing material.

[0059] For example, FIG. 13A shows a device 1300 including a first glass substrate 1302, a second glass substrate 1304, and an LC layer 1306 deposited between the first and second glass substrates 1302 and 1304. Each of the first and second glass substrates 1302 and 1304 may be made of low-loss glass, for example, with an FSS pattern. Additionally, an optical filter substrate 1310 is deposited on the first glass substrate 1302 to protect it from light exposure. The side of the device 1300 having the optical filter substrate 1310 would be the side facing a potential light source (e.g., the outside of the LCD panel). The optical filter substrate 1310 may include, for example, a UV / IR filter or film made of UV / IR-absorbing dyes, a UV filter material such as polyester or metal oxide, or any other suitable material.

[0060] In some examples, in addition to or instead of the light filter substrate, the device can include a light-absorbing material in the LC layer. For example, FIG. 13B shows a device 1350 that also includes a first glass substrate 1302, a second glass substrate 1304, and an LC layer 1306 deposited between the first glass substrate 1302 and the second glass substrate 1304. Additionally, the device 1350 also includes a light filter substrate 1310 deposited on the first glass substrate 1302 to protect it from light exposure. The LC layer 1306 in this example includes a light-absorbing and / or scattering material 1320. The light-absorbing and / or scattering material 1320 may include, for example, a UV / IR-absorbing dye, a UV stabilizer, benzophenone, p-aminobenzoic acid (PABA), 4-tert-butyl-4′-methoxydibenzoylmethane (avobenzone), or ethylhexyl methoxycinnamate (EHMC). Examples of UV scattering materials would include titanium oxide (TiO2) and zinc oxide (ZnO).

[0061] Illustrative Embodiments In some embodiments, the unit cell device includes a first metal layer and a second metal layer, each of which is deposited within a glass substrate, the first metal layer having a first size and the second metal layer having a second size, the first size and the second size being different, and an LC layer disposed between the first metal layer and the second metal layer.

[0062] In some embodiments, the second size is smaller than the first size, hi some embodiments, the second size is at least 10% smaller than the first size.

[0063] In some embodiments, the first metal layer includes a plurality of columns and the second metal layer includes a plurality of rows. In some embodiments, each of the plurality of columns is electrically connected to a power source. In some embodiments, each of the plurality of rows is connected to ground. In some embodiments, each of the plurality of rows is connected to a power source. In some embodiments, each of the plurality of columns includes a first plurality of LC active layers and each of the plurality of rows includes a second plurality of LC active layers. In some embodiments, each of the first plurality of LC active layers is laterally offset from one of the second plurality of LC active layers.

[0064] In some embodiments, the first metal layer is connected to at least one power supply and the second metal layer is connected to ground.

[0065] In some embodiments, the glass substrate comprises a first glass substrate portion and a second glass substrate portion, a first metal layer disposed between the first glass substrate portion and the liquid crystal layer, a second metal layer disposed between the liquid crystal layer and the second glass substrate portion, the device further comprising a third metal layer, and the second glass substrate portion disposed between the second metal layer and the third metal layer.

[0066] In some embodiments, the device includes an optical filter substrate deposited on a glass substrate.

[0067] In some embodiments, the liquid crystal layer comprises a light absorbing material.

[0068] In some embodiments, the device includes a plurality of LC active areas between a first metal layer and a second metal layer, wherein liquid crystals of the liquid crystal layer within the plurality of LC active areas tilt when a bias voltage is applied between the first metal layer and the second metal layer, and in some embodiments, liquid crystals of the liquid crystal layer outside the plurality of LC active areas do not tilt when a bias voltage is applied between the first metal layer and the second metal layer.

[0069] In some embodiments, the unit cell device includes a first metal layer and a second metal layer deposited within a glass substrate, the first metal layer being laterally offset from the second metal layer. The first metal layer includes a plurality of columns, each of the plurality of columns including a first plurality of LC active layers. The second metal layer includes a plurality of rows, each of the plurality of rows including a second plurality of LC active layers. The unit cell device further includes an LC layer deposited between the first metal layer and the second metal layer.

[0070] In one example, a method, such as by an apparatus (e.g., a pick-and-place apparatus) having one or more processors executing instructions, includes depositing a metal material on a first glass substrate to form a first metal layer having a first size. The method may also include depositing an LC material on the first metal layer to form an LC layer. Further, the method may also include depositing a metal material on the LC layer to form a second metal layer having a second size different from the first size. The method may also include depositing a second glass substrate on the second metal layer.

[0071] In one example, a method, such as by an apparatus (e.g., a pick-and-place apparatus) having one or more processors executing instructions, includes depositing a metal material on a first glass substrate to form a first metal layer having a first plurality of LC active layers. The method may also include depositing an LC material on the first metal layer to form an LC layer. Further, the method may also include depositing a metal material on the LC layer to form a second metal layer having a second plurality of LC active layers. The method may also include depositing a second glass substrate on the second metal layer.

[0072] In some embodiments, a non-transitory computer-readable medium stores instructions that, when executed by one or more processors, cause an apparatus, such as a pick-and-place apparatus, to perform a method including depositing a metal material on a first glass substrate to form a first metal layer having a first size. The method can also include depositing an LC layer on the first metal layer to form an LC layer. Further, the method can also include depositing a metal material on the LC layer to form a second metal layer having a second size different from the first size. The method can also include depositing a second glass substrate on the second metal layer.

[0073] In some embodiments, a non-transitory computer-readable medium stores instructions that, when executed by one or more processors, cause an apparatus, such as a pick-and-place apparatus, to perform a method including depositing a metal material on a first glass substrate to form a first metal layer including a first plurality of LC active layers. The method can also include depositing an LC material on the first metal layer to form an LC layer. Further, the method can also include depositing a metal material on the LC layer to form a second metal layer including a second plurality of LC active layers. The method can also include depositing a second glass substrate on the second metal layer.

[0074] Although a method is described above, it will be appreciated that many other ways of performing the acts associated with the method may be used. For example, the order of some operations may be changed, and some of the operations described may be optional.

[0075] Additionally, the methods and systems described herein may be embodied, at least to some extent, in the form of computer-implemented processes and apparatuses for practicing those processes. The disclosed methods may also be embodied, at least to some extent, in the form of a tangible, non-transitory, machine-readable storage medium encoded with computer program code. For example, the method steps may be embodied in hardware, in executable instructions (e.g., software) executed by a processor, or in a combination of the two. Examples of such media may include RAM, ROM, CD-ROM, DVD-ROM, BD-ROM, a hard disk drive, a flash memory, or any other non-transitory, machine-readable storage medium. When computer program code is loaded into a computer and executed, the computer becomes an apparatus for practicing the method. The method may also be embodied, at least to some extent, in a computer into which the computer program code is loaded and executed, thereby making the computer a dedicated computer for practicing the method. When implemented on a general-purpose processor, the computer program code segments configure the processor to create specific logic circuits. Alternatively, the method may be embodied, at least to some extent, in an application-specific integrated circuit for performing the method.

[0076] The foregoing description has been presented for the purposes of illustrating, explaining, and describing embodiments of the present disclosure. Modifications and adaptations to these embodiments will become apparent to those skilled in the art and may be made without departing from the scope or spirit of the present disclosure.

[0077] Preferred embodiments of the present invention will be described below in detail.

[0078] Embodiment 1 On the device, Glass substrate, a first metal layer and a second metal layer, each of the first metal layer and the second metal layer being deposited within the glass substrate, the first metal layer having a first size and the second metal layer having a second size, the first size being different from the second size; and a liquid crystal layer disposed between the first metal layer and the second metal layer; A device with.

[0079] Embodiment 2 the first metal layer includes a plurality of columns; 2. The device of embodiment 1, wherein the second metal layer comprises a plurality of rows, and the plurality of columns are perpendicular to the plurality of rows.

[0080] Embodiment 3 3. The device of embodiment 2, wherein each of the plurality of strings is electrically connected to a first power source.

[0081] Embodiment 4 4. The device of embodiment 3, wherein each of the plurality of rows is connected to ground.

[0082] Embodiment 5 4. The device of embodiment 3, wherein each of the plurality of rows is connected to a second power supply.

[0083] Embodiment 6 3. The device of embodiment 2, wherein each of the plurality of columns comprises a first plurality of LC active layers and each of the plurality of rows comprises a second plurality of LC active layers.

[0084] Embodiment 7 7. The device of embodiment 6, wherein each one of the first plurality of LC active layers is laterally offset from one of the second plurality of LC active layers.

[0085] Embodiment 8 2. The device of embodiment 1, wherein the second size is smaller than the first size.

[0086] Embodiment 9 6. The device of embodiment 5, wherein the second size is at least 10% smaller than the first size.

[0087] Embodiment 10 2. The device of embodiment 1, wherein the first metal layer is connected to a power supply and the second metal layer is connected to ground.

[0088] Embodiment 11 10. The device of claim 1, wherein the glass substrate comprises a first glass substrate portion and a second glass substrate portion, the first metal layer being disposed between the first glass substrate portion and the liquid crystal layer, the second metal layer being disposed between the liquid crystal layer and the second glass substrate portion, and the device comprises a third metal layer, the second glass substrate portion being disposed between the second metal layer and the third metal layer.

[0089] Embodiment 12 10. The device of embodiment 1, comprising an optical filter substrate deposited on the glass substrate.

[0090] Embodiment 13 10. The device of embodiment 1, wherein the liquid crystal layer comprises a light-absorbing material.

[0091] Embodiment 14 2. The device of claim 1, comprising a plurality of LC active layers between the first metal layer and the second metal layer, wherein liquid crystals in the liquid crystal layer within the plurality of LC active layers tilt when a bias voltage is applied between the first metal layer and the second metal layer.

[0092] Embodiment 15 15. The device of claim 14, wherein the liquid crystals in the liquid crystal layer outside the plurality of LC active layers do not tilt when a bias voltage is applied between the first metal layer and the second metal layer.

[0093] Embodiment 16 On the device, Glass substrate, a first metal layer and a second metal layer, each of the first metal layer and the second metal layer deposited within the glass substrate, the first metal layer including a plurality of columns and the second metal layer including a plurality of rows, each of the plurality of columns and each of the plurality of rows electrically connected to a first power supply and a second power supply, respectively; a liquid crystal layer disposed between the first metal layer and the second metal layer; A device with.

[0094] Embodiment 17 17. The device of embodiment 16, wherein each of the plurality of columns includes a first plurality of LC active layers and each of the plurality of rows includes a second plurality of LC active layers, each of the first plurality of LC active layers being laterally offset from one of the second plurality of LC active layers.

[0095] Embodiment 18 depositing a metal material on a first glass substrate to form a first metal layer having a first size; depositing a liquid crystal (LC) material onto the first metal layer to form an LC layer; depositing the metal material on the LC layer to form a second metal layer having a second size different from the first size; and depositing a second glass substrate on the second metal layer; A method comprising:

[0096] Embodiment 19 the first metal layer includes a plurality of columns; 19. The method of embodiment 18, wherein the second metal layer comprises a plurality of rows.

[0097] Embodiment 20 20. The method of embodiment 19, wherein each of the plurality of columns comprises a first plurality of LC active layers and each of the plurality of rows comprises a second plurality of LC active layers. [Explanation of symbols]

[0098] 100, 400, 700, 850 RIS devices 102, 402, 702, 920, 1206, 1302 First glass substrate 104, 404, 704, 922, 1208, 1304 Second glass substrate 110, 410, 709 First metal layer 112, 412, 412A-E, 710, 712 Multiple metal rows 114, 414 first plurality of LC active layers 120, 420, 719 Second metal layer 122, 422, 422A-E, 720, 722 Multiple metal rows 124, 424 Second multiple LC active layers 130, 430, 730, 910, 1210, 1306 LC layer 140, 740 Third metal layer 201, 860, 862, 1101, 1105, 1212, 1214 LC 204, 415A~415E, 475A~E, 715A~B, 725A~B, 1220 power supply 417 Earth 802 Passive FSS Device 850, 900, 1100, 1200, 1300, 1350 devices 852 Glass substrate 854 unit cell 902 first bias voltage electrode 904 Second bias voltage electrode 1102, 1215 LC active area 1120 area 1202 First electrode 1204 Second electrode 1310 Optical filter substrate 1320 Light-absorbing materials

Claims

1. On the device, Glass substrate, a first metal layer and a second metal layer, each of the first metal layer and the second metal layer being deposited within the glass substrate, the first metal layer having a first size and the second metal layer having a second size, the first size being different from the second size; and a liquid crystal layer disposed between the first metal layer and the second metal layer; A device with.

2. the first metal layer includes a plurality of columns; The device of claim 1 , wherein said second metal layer comprises a plurality of rows, and said plurality of columns are perpendicular to said plurality of rows.

3. The device of claim 2 , wherein each of the plurality of strings is electrically connected to a first power supply.

4. 4. The device of claim 3, wherein each of said plurality of rows is connected to ground.

5. The device of claim 3 , wherein each of the plurality of rows is connected to a second power supply.

6. The device of claim 2 , wherein each of the plurality of columns includes a first plurality of LC active layers and each of the plurality of rows includes a second plurality of LC active layers.

7. The device of claim 6 , wherein each one of the first plurality of LC active layers is laterally offset from one of the second plurality of LC active layers.

8. The device of claim 1 , wherein the second size is smaller than the first size.

9. The device of claim 5 , wherein the second size is at least 10% smaller than the first size.

10. 2. The device of claim 1, wherein the first metal layer is connected to a power supply and the second metal layer is connected to ground.

11. 10. The device of claim 1, wherein the glass substrate comprises a first glass substrate portion and a second glass substrate portion, the first metal layer is disposed between the first glass substrate portion and the liquid crystal layer, the second metal layer is disposed between the liquid crystal layer and the second glass substrate portion, and the device comprises a third metal layer, the second glass substrate portion is disposed between the second metal layer and the third metal layer.

12. The device of claim 1 further comprising an optical filter substrate disposed on said glass substrate.

13. The device of claim 1 , wherein the liquid crystal layer comprises a light-absorbing material.

14. 2. The device of claim 1, further comprising a plurality of LC active layers between the first metal layer and the second metal layer, wherein when a bias voltage is applied between the first metal layer and the second metal layer, the liquid crystal of the liquid crystal layer within the plurality of LC active layers tilts.

15. 15. The device of claim 14, wherein liquid crystals in the liquid crystal layer outside the plurality of LC active layers do not tilt when a bias voltage is applied between the first metal layer and the second metal layer.

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