Cationic gettering in liquid crystal NCAP and PDLC films

Abstract

An electro-optical modulator is disclosed. The electro-optical modulator comprises a modulator material film layer. The modulator material film layer includes a polymer matrix. Liquid crystals and gettering molecules are dispersed within the polymer matrix. The liquid crystal is configured to modulate light transmittance through the electro-optical modulator. The gettering molecules capture or coordinate with cationic impurities present within the polymer matrix. The switching of the device at modulated low frequencies is improved and the switching voltage of the device is reduced by the defaulting of the cationic impurities. So far, three types of gettering molecules are proved to be effective: an inorganic ion trap (ammonium dihydrogen phosphate), an organic cation trap (EDTA) and an organic ion extraction agent (nicotinic acid). The amount of gettering molecules may be from 0.01 to 1.0 weight percent of the polymer matrix.

Description

Technical Field

[0001] The present invention relates generally to electro-optics, and more particularly to polymer dispersed liquid crystal materials for electro-optical applications. Background Art

[0002] Electro-optic modulators using liquid crystals, especially in the form of NCAP or PDLC films, for modulation are used to test the conductivity of thin film transistors and interconnects of flat panel displays (FPDs) under manufacturing. The presence of metal cations in the detection layer of the modulator, originating from changes in introduced raw material chemicals or formulation marginalities, may adversely affect modulator performance by affecting dielectric properties. In particular, metal cations may migrate within the electro-optic modulator in response to an electric field. The migration of cations may cause the cations to electrostatically shield the liquid crystal of the electro-optic modulator. Therefore, it would be advantageous to provide a device, system, and method that eliminate the disadvantages described above. Summary of the invention

[0003] According to one or more illustrative embodiments of the present disclosure, an electro-optic modulator is disclosed. In one illustrative embodiment, the electro-optic modulator includes a polymer matrix. In another illustrative embodiment, the electro-optic modulator includes liquid crystal molecules dispersed in the polymer matrix. In another illustrative embodiment, the electro-optic modulator includes a getter molecule dispersed in the polymer matrix. In another illustrative embodiment, the getter molecule and the polymer matrix are each soluble in a solvent. In another illustrative embodiment, the getter molecule is insoluble in the liquid crystal molecule. In another illustrative embodiment, each of the getter molecules includes a cation and an anion configured to getter one or more cationic impurities of the polymer matrix.

[0004] According to one or more embodiments of the present disclosure, an imaging system is disclosed. In one illustrative embodiment, the imaging system includes an illumination source configured to generate illumination. In another illustrative embodiment, the imaging system includes a support for a sample. In another illustrative embodiment, the imaging system includes an electro-optic modulator disposed in the path of illumination from the illumination source and separated from the sample by an air gap. In another illustrative embodiment, the electro-optic modulator includes a polymer matrix. In another illustrative embodiment, the electro-optic modulator includes liquid crystal molecules dispersed in the polymer matrix. In another illustrative embodiment, the electro-optic modulator includes a getter molecule dispersed in the polymer matrix. In another illustrative embodiment, the getter molecule and the polymer matrix are each soluble in a solvent. In another illustrative embodiment, the getter molecule is insoluble in the liquid crystal molecule. In another illustrative embodiment, each of the getter molecules includes a cation configured to getter one or more cationic impurities of the polymer matrix and its counter anion. In another illustrative embodiment, the getter molecule may include a chelating interaction. In another illustrative embodiment, the imaging system includes a detector for generating an image of at least a portion of the sample.

[0005] According to one or more embodiments of the present disclosure, a method for manufacturing an electro-optic modulator is disclosed. In one illustrative embodiment, the method includes adding a getter molecule to a solution including polymer molecules dissolved in a solvent. In another illustrative embodiment, the method includes adding a liquid crystal to the solution. In another illustrative embodiment, the method includes emulsifying the liquid crystal in the solution to disperse the liquid crystal, thereby forming a mixture. In another illustrative embodiment, the method includes coating a substrate with the mixture to form a film. In another illustrative embodiment, the method includes drying the film. In another illustrative embodiment, the film includes a polymer matrix formed by polymer molecules. In another illustrative embodiment, the film includes liquid crystal molecules dispersed in the polymer matrix. In another illustrative embodiment, the film includes the getter molecule dispersed in the polymer matrix. In another illustrative embodiment, the getter molecule is soluble in the solvent. In another illustrative embodiment, the getter molecule is insoluble in the liquid crystal molecule. In another illustrative embodiment, each of the getter molecules includes an anion configured to getter one or more cationic impurities of the polymer matrix.

[0006] According to one or more embodiments of the present disclosure, a polymeric composition is disclosed. In one illustrative embodiment, the polymeric composition includes a polymer matrix formed by cross-linking a plurality of molecules. In another illustrative embodiment, the polymeric composition includes a gettering molecule dispersed in the polymer matrix. In another illustrative embodiment, the gettering molecule and the polymer matrix are each soluble in a solvent. In another illustrative embodiment, the solvent is water. In another illustrative embodiment, the gettering molecule includes a cation and an anion configured to getter one or more cationic impurities disposed in the polymer matrix. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The advantages of the present disclosure may be better understood by those skilled in the art with reference to the accompanying drawings, in which:

[0008] Figure 1A A cross-sectional view of an electro-optic modulator according to one or more embodiments of the present disclosure is shown.

[0009] Figure 1B Plots of transmittance versus voltage are shown for electro-optic modulators with and without the disclosed gettering molecules according to one or more embodiments of the present disclosure.

[0010] Figure 2 A flow chart of a method for manufacturing an electro-optic modulator according to one or more embodiments of the present disclosure is shown.

[0011] Figure 3 A simplified diagram of an imaging system is shown in accordance with one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0012] The present disclosure has been specifically shown and described with respect to certain embodiments and specific features thereof. The embodiments set forth herein should be considered illustrative rather than restrictive. It should be apparent to one of ordinary skill in the art that various changes and modifications may be made to form and detail without departing from the spirit and scope of the present disclosure. Reference will now be made in detail to the disclosed subject matter, which is illustrated in the accompanying drawings.

[0013] The polymer matrix of an electro-optic modulator based on a nematic curve alignment phase (NCAP) or a polymer dispersed liquid crystal (PDLC) film may include cations or cationic impurities. Cationic impurities may be present in the polymer matrix depending on the manner in which the polymer raw material or polymer matrix is ​​prepared. For example, the polymer matrix may be formed by dissolving water-soluble polymer molecules in water to form an aqueous solution. The aqueous solution may be weakly alkaline (e.g., between pH 7.5 and pH 9). Fluctuations in the cationic content of the aqueous solution may vary based on several factors, such as, but not limited to, the raw material chemicals or formulation margins introduced to prepare the polymer matrix. The polymer matrix may include any type of cations, such as, but not limited to, metal cations. For example, the metal cations may include sodium, potassium, magnesium, calcium, etc. The cations may be electromigrated within the polymer matrix. For example, potassium ions in the polymer matrix may be electromigrated and drift in response to an electric field. By migrating, the potassium cations may electromagnetically shield the liquid crystals dispersed in the polymer matrix. Electromagnetic shielding may affect the switching characteristics of the electro-optic modulator, which is undesirable. In particular, the switching characteristics of electro-optic modulators may be suboptimal in certain pulse modes due to sodium or potassium cation contamination. Thus, excessive ion contamination in the polymer matrix of electro-optic modulators has been shown to degrade the switching performance with respect to both the on-voltage and the response to changes in the frequency of the electric field. Various getter molecules may be used as a solution to mitigate the effects of ions.

[0014] Embodiments of the present disclosure are generally directed to an electro-optic modulator that includes one or more getter molecules for capturing cationic impurities present in a polymer matrix of the electro-optic modulator. The getter molecules can getter metal cations present in the polymer matrix, such as (but not limited to) potassium cations. The getter molecules can also include high solubility and / or reactivity with the polymer matrix, especially when the polymer matrix is ​​in an aqueous solution, for the gettering of metal cations. The getter molecules can also be selected to minimize pH changes in the aqueous solution. The anions of the getter molecules can getter, capture or otherwise collect cationic impurities present and migrating within the polymer matrix. Upon further consideration, the getter molecules can include one or more cations (e.g., ammonium) that passivate one or more dangling bond electron trap states or other interstitial states that conduct by hopping. Passivating the electron trap states can reduce electrostatic screening of one or more liquid crystal (LC) molecules dispersed in the polymer matrix, thereby reducing the threshold field and / or hysteresis effect required to switch the liquid crystal. The reduction in the threshold field can improve the switching performance of the liquid crystal and can reduce the turn-on voltage required for liquid crystal alignment. The getter molecule may also have low solubility in the liquid crystal. The electro-optic modulator may be a component of an imaging system, also referred to as an automated optical inspection (AOI) system, a voltage imaging optical system (VIOS), an array inspector, etc. Process improvements for optical inspection may similarly be improved by reducing the turn-on voltage. Embodiments of the present disclosure also relate to methods of forming an electro-optic modulator.

[0015] Electro-optic modulators are generally described in: U.S. Pat. No. 6,151,153, issued on November 21, 2000, entitled MODULATOR TRANSFER PROCESS AND ASSEMBLY; U.S. Pat. No. 6,211,991, issued on April 3, 2001, entitled MODULATOR MANUFACTURING PROCESS AND DEVICE; U.S. Pat. No. 6,866,887, issued on March 15, 2005, entitled METHOD FOR MANUFACTURING PDLC-BASED ELECTRO-OPTIC MODULATOR USING SPINCOATING; U.S. Pat. No. 6,866,887, issued on March 15, 2005, entitled SCRATCH AND MAR RESISTANT PDLC MODULATOR; No. 7,099,067, entitled “MODULATOR WITH IMPROVEDSENSITIVITY AND LIFETIME,” issued on August 29, 2006; No. 7,817,333, entitled “MODULATOR WITH IMPROVEDSENSITIVITY AND LIFETIME,” issued on October 19, 2010; and No. 8,801,964, entitled “ENCAPSULATED POLYMER NETWORK LIQUIDCRYSTAL MATERIAL, DEVICE AND APPLICATIONS,” issued on August 12, 2014, each of which is incorporated herein by reference in its entirety.

[0016] Figure 1A A cross-sectional view of an electro-optic modulator 100 is depicted according to one or more embodiments of the present disclosure, the electro-optic modulator including an ionic gettering material added to a polymer matrix of the electro-optic modulator 100. The electro-optic modulator 100 may include one or more layers, such as, but not limited to, a modulator material layer 108. The modulator material layer 108 may include a polymer matrix, liquid crystal droplets, and gettering molecules. The polymer matrix may include cations or other cationic impurities that increase the drive voltage required to switch the liquid crystals dispersed therein. The gettering molecules may be dispersed within the polymer matrix to getter the cations, thereby reducing the switching voltage. The gettering molecules may include one or more properties, such as, but not limited to, the ability to disperse within the polymer matrix, solubility in water or a host solvent, insolubility in liquid crystal molecules, and / or the ability to getter (i.e., capture) cations. Many such gettering molecules are contemplated and described herein.

[0017] In an embodiment, the modulator material layer 108 may include one or more of the getter molecules. The getter molecules may include one or more anions to getter or otherwise chelate cationic impurities from the matrix. In order to getter the cationic impurities, the getter molecules may generally include anions. For example, the getter molecules may include anions and cations that migrate in response to an electric field. The anions may then be free to getter the cationic impurities (e.g., potassium or other metal cations) of the polymer matrix. In this regard, the cationic impurities are immobilized and the charge is neutralized. For example, the anions of the getter molecules may include any of the following: phosphate, carboxylate, sulfate, carbonate, thiosulfate, sulfite, acetate, borate, etc. By way of another example, the cations may include any of hydrogen, ammonium, hydronium, alkyl, etc. Therefore, adding getter molecules to the modulator material layer 108 of the electro-optic modulator may reduce the voltage required to switch the liquid crystal of the modulator material layer 108. The getter molecules may then provide improved switching characteristics of the polymer containing cationic impurities. It is contemplated that the reduced voltage may be attributable to the cation of the getter molecule passivating one or more electron trap states, although this is not intended to be limiting.

[0018] In an embodiment, the cation comprises an organic group. In an embodiment, the organic group comprises a compound or group comprising two carbon atoms bonded together, wherein at least one carbon atom is bonded to at least one of hydrogen and / or halogen. In addition, a carbon atom may be bonded to at least one nitrogen atom by a single bond or a double bond. The organic group may comprise any suitable organic group, such as (but not limited to) n-butyl, n-propyl or isopropyl. Isopropyl p-toluenesulfonate, n-butyl acetate are examples of cation-anion combinations that can remove defects in metal cations.

[0019] In an embodiment, the polymer matrix and the getter molecule are soluble in a common solvent. For example, the solvent may include water, which forms an aqueous solution, although this is not intended to be limiting. The getter molecule may be water soluble by including a polar molecule that is soluble in an aqueous solution (e.g., including polymer molecules and water) to ionize and form an anion. The anion may include a negative charge for electrostatic coupling with a cation present in the polymer matrix. In addition, by being water soluble, the getter molecule may be dispersed in the polymer matrix, such as during liquid crystal emulsification. For example, the NCAP film may be formed from an aqueous solution.

[0020] In embodiments, the gettering molecule may be compatible with polymer molecules used to form the polymer matrix, such as, but not limited to, polyvinyl alcohol (PVA), polyurethane, or polyacrylate. The gettering molecule may also be compatible with one or more additives, such as, but not limited to, surfactants used to formulate the polymer matrix. In embodiments, the gettering molecule does not substantially change the pH of the aqueous solution. In this regard, the polymer molecules dissolved in the aqueous solution may include a pH between pH 7.5 and pH 9. By not affecting the pH of the aqueous solution, the crosslinking of the polymer molecules forming the polymer matrix may similarly not be affected.

[0021] In an embodiment, the getter molecule is insoluble in the liquid crystal material. By being insoluble in the liquid crystal material, the getter molecule can avoid interfering with the switching of the liquid crystal or acting as an interfacial agent. By not acting as an interfacial agent, the getter molecule can have minimal effect on the anchoring or friction between the polymer matrix and the liquid crystal. In addition, the getter molecule is dispersed in the polymer matrix rather than the liquid crystal. In some embodiments, the getter can enhance the hardness of the polymer matrix. For example, the NCAP film can be harder when the getter is present in the film.

[0022] It is contemplated that a variety of decontamination molecules may be configured to decontaminate one or more cations of a polymer matrix. Decontamination molecules may generally include a variety of organic or inorganic compounds. Cationic abstraction may be performed by one or more classes of decontamination molecules, such as, but not limited to, inorganic salts with cation reactivity, organic compounds with cation extraction capabilities, or organic compounds with cation extraction properties.

[0023] In an embodiment, the decontamination molecule may include one or more organic or inorganic acids and / or salts thereof. The decontamination molecule may include a cation that can be displaced from an anion. The anion can then decontaminate cationic impurities of the polymer matrix. The decontamination molecule can be selected based on the pKa value. The pKa is a measure of acidity and provides an estimate of the stability of the anion formed in an aqueous solution. For example, the decontamination molecule may include any of the chemical substances provided in Table 1, and may further include a cation selected from one of hydrogen, ammonium, hydronium, or an organic group.

[0024] Table 1

[0025]

[0026] In some examples, the pKa value provides a basis for selecting a decontamination molecule. The decontamination molecule may be selected to have a pKa value that is not too low and thus does not substantially lower the pH of the solution and similarly interfere with crosslinking. The decontamination molecule may be selected to have a pKa value that is not too high and thus does not cause insufficient dissociation or otherwise provide sufficient impurity decontamination. The concentration may also be selected so as not to significantly change the pH so that crosslinking of the polymer is not significantly hindered. For example, the decontamination molecule may be selected to have a pKa between 0 and 3, such as nicotinic acid, ammonium dihydrogen phosphate, or ethylenediaminetetraacetic acid (EDTA), although this is not intended to be limiting. Solubility and chemical compatibility may also provide a basis for selecting a decontamination molecule to avoid phase separation or further aggregation of the polymer in solution. The degree of ionization and the equilibrium constant (Ka) of the ionization may also provide a basis for selecting the cation of the chemical. In this regard, a buffer solution may be composed of a compound (or mixture) for pH control and based on ionic strength.

[0027] In an embodiment, the defect removal molecule includes a phosphate group. The phosphate group can be considered to ensure sufficient crosslinking by taking into account the overall pH of the formulation, including phosphate ([PO4] 3- ), hydrogen phosphate ([HPO4] 2- ), dihydrogen phosphate ([H2PO4] 1- ) or phosphoric acid (H3PO4). Similarly, the defect removal molecule may include cations such as, but not limited to, hydrogen, ammonium, or hydronium, and phosphate ([PO4] 3- ), hydrogen phosphate ([HPO4] 2- ), dihydrogen phosphate ([H2PO4] 1- )

[0028] For example, the defect removal molecule may include diammonium phosphate. The diammonium phosphate may include a molecule according to the following formula:

[0029]

[0030] Ammonium dihydrogen phosphate has been experimentally successful as a decontamination molecule. When ammonium dihydrogen phosphate is added to NCAP or PDLC films, the dihydrogen phosphate moiety can decontaminate cationic impurities. Although ammonium is a cation, it has been experimentally determined that ammonium does not adversely affect the switching characteristics, but instead improves the switching characteristics. It is considered that the improvement in switching behavior can be attributed to ammonium passivating one or more dangling bonds or other interstitial states. For example, the NCAP or PDLC film may include one or more dangling bonds (e.g., with unsaturated valence) or other interstitial states that can be conducted by jumping. Dangling bonds may improperly hinder conduction and charging. Therefore, ammonium can improve the conduction and charging capabilities of the NCAP or PDLC film by passivation, but this is not intended to be limiting.

[0031] Upon further consideration, the defect removal molecule may include a sulfonic acid or a sulfonate thereof. The sulfonic acid may include a sulfonic acid according to the following formula, wherein R is an organic group:

[0032]

[0033] Sulfonic acid can be included in a variety of chemical substances, such as (but not limited to) polystyrene sulfonic acid or its polystyrene sulfonate. Polystyrene sulfonate can include according to the following formula:

[0034]

[0035] Amberlite resins may be based on the polystyrene sulfonic acid or a salt thereof. Polystyrene sulfonates may typically include one or more cations such as, but not limited to, hydrogen, ammonium, or hydronium. For example, the getter molecule may include ammonium polystyrene sulfonate.

[0036] In an embodiment, the decontamination molecule includes a carboxylic acid group. The decontamination molecule including the carboxylic acid group is soluble in water (e.g., an aqueous solution including a polymer) and can remove cationic impurities from a polymer matrix. The carboxylic acid group can be an organic acid containing a carboxyl group attached to an R-group. Carboxylates can also be used as decontamination molecules. The carboxylate can include a carboxylate group attached to an R-group. The carboxylate group can include M, wherein M is selected from one of hydrogen, ammonium, or hydronium. The carboxylate can include a formula according to the following:

[0037]

[0038] In an embodiment, the decontamination molecule may include one or more organic compounds with cation extraction capabilities. Chelating agents are a class of compounds that reactively remove metal ions. Chelating agents may include anions that are reactive with cationic impurities of a polymer matrix or coordinate with cations when the reagent does not have anions. For example, chelating agents may include, but are not limited to, ethylenediaminetetraacetic acid (EDTA) or its salts. EDTA may include a multidentate structure for ion extraction. The multidentate structure may include four carboxylic acid groups and / or carboxylate groups, each of which may be used as a cation receptor site for extracting or removing cationic impurities. Therefore, one or more of the carboxylic acid groups and / or carboxylate groups may serve as an organic decontamination agent for potassium or other cationic impurities of a polymer matrix. In addition, EDTA may include suitable water miscibility and sufficient purity. EDTA may include according to the following formula:

[0039]

[0040] In an embodiment, the defect removal molecule may include one or more organic compounds having cation extraction capabilities. Ionophores are a class of molecules used in medicine for ion transport. There are many such ionophores, such as (but not limited to) valinomycin. valinomycin can be used as an ionophore for potassium. valinomycin can include a formula according to the following:

[0041]

[0042] The ionophore may also include nicotinic acid or a salt thereof. It has been experimentally determined that nicotinic acid acts as a getter molecule for potassium ions in a polymer matrix. Nicotinic acid may include a carboxylic acid group that may act as an organic ion extractant for potassium or other cationic impurities of the polymer matrix. Similarly, a salt of nicotinic acid may include a carboxylate group. For example, nicotinic acid may include a formula according to:

[0043]

[0044] In an embodiment, an amount of a getter molecule is added to the polymer matrix. The amount may be selected based on the level of cationic impurities present in the aqueous solution. For example, between 0.01 and 1.0% of the polymer matrix may be added to the aqueous solution. The getter molecule may be added during the initial stages of electro-optic modulator formulation, such as, but not limited to, before adding the liquid crystal to the aqueous solution.

[0045] Therefore, the modulator material layer 108 may include one or more of a polymer matrix, a liquid crystal, and one or more getter molecules. In an embodiment, in addition to the modulator material layer 108, the electro-optic modulator 100 may also include one or more films, layers, or coatings. For example, the electro-optic modulator 100 may include one or more of the following: a hard coating 102, a plastic film 104, a dielectric mirror film 106, a modulator material layer 108, a transparent conductive layer 110, a plastic film 112, an optical adhesive 114, a glass substrate 116, and / or an anti-reflective coating 118. The electro-optic modulator 100 may therefore include one or more film layers that allow transmission of light. The light transmittance passing through the modulator material layer 108 may also change according to the magnitude of the electric field felt by the liquid crystal of the modulator material layer 108. Upon further consideration, the electro-optic modulator is not intended to be limited to the films, layers, or coatings described above.

[0046] The modulator material layer 108 (also referred to as a sensor layer, liquid crystal layer, polymer matrix layer, etc.) may be applied to the glass substrate 116 by a variety of methods such as, but not limited to, direct coating or lamination. An embodiment made with a lamination process includes first coating a plastic film 112 (e.g., polyethylene terephthalate (PET), also known as Mylar) having a transparent conductive layer 110 with the modulator material layer. The transparent conductive layer 110 may generally include any material that is optically transparent and conductive to act as an electrode, such as, but not limited to, indium tin oxide (ITO). The modulator material layer 108 may include a NCAP blend or a PDLC blend. The plastic film 112 and similarly the transparent conductive layer 110 and modulator material layer 108 may be laminated to the glass substrate 116 by an optical adhesive 114. A dielectric mirror film 106 (or pellicle) may be formed on the plastic film 104 and then added to the modulator material layer 108 of the assembly stack. The dielectric mirror coating may be deposited by physical vapor deposition or a similar process. In an embodiment, a vacuum assisted attachment process is used. The dielectric mirror film 106 may be capacitively coupled to the sample to induce a local voltage. The local voltage may then cause the liquid crystal in the modulator material layer 108 to align. An anti-reflective coating 118 may be applied to the bottom surface of the glass substrate 116. Similarly, a hard coating 102 may be cured on the plastic film 104. The hard coating 102 may include a main hard coating and a thinner lubricant layer.

[0047] View now Figure 1B , a graph 101 of transmittance versus voltage is depicted according to one or more embodiments of the present disclosure. Graph 101 depicts the normalized transmittance of the electro-optic modulator 100 as a function of voltage without and with getter molecules. Curve 103 represents a reference VT curve obtained from an electro-optic modulator that does not contain getter molecules in the NCAP film. Curve 105 represents a VT curve obtained from an electro-optic modulator that includes a 0.2% getter molecule concentration in the NCAP film. As shown in graph 101, the presence of getter molecules in the electro-optic modulator enables sufficient transmittance to be achieved at a voltage lower than that required in the non-getter case.

[0048] Figure 2 Flowchart showing steps performed in a method 200 for manufacturing an electro-optic modulator according to one or more embodiments of the present disclosure. In the case of the electro-optic modulator 100, the embodiments and enabling techniques previously described herein should be interpreted as being applicable to the method 200. However, it should be further noted that the method 200 is not limited to the architecture of the electro-optic modulator 100.

[0049] In step 210, a gettering molecule is added to a solution of polymer molecules dissolved in a solvent. For example, the polymer dissolved in the solvent may be polyvinyl alcohol (PVA) or a carbamate dissolved in water to form an aqueous solution. It is further contemplated that the solvent may be another solvent used in the formulation of the PDLC film, such as, but not limited to, a solvent used for latex polymers, monomers, etc. The solution may be a homogeneous solution. In an embodiment, the gettering molecule may be any of the gettering molecules previously described herein. For example, the gettering molecule may include a variety of formulations, such as, but not limited to, nicotinic acid or another nicotinic acid salt (e.g., ammonium nicotinate), ethylenediaminetetraacetic acid (EDTA) or another ethylenediaminetetraacetic acid salt (e.g., ammonium ethylenediaminetetraacetate), iminodisuccinic acid, polyaspartic acid, valinomycin, dihydrogen phosphate (e.g., diammonium phosphate), and / or polystyrene sulfonic acid or another polystyrene sulfonate salt (e.g., ammonium polystyrene sulfonate). The gettering molecule may also be insoluble in the liquid crystal. The gettering molecule may be added based on the relative weight of the gettering molecule to the polymer molecule. For example, the getter molecule comprises 0.01 to 1.0 weight percent of the polymer molecule.

[0050] In step 220, liquid crystals are added to the aqueous solution to form a mixture. The combination of the liquid crystal and the aqueous solution may be a two-phase mixture. In this regard, the liquid crystal may be relatively immiscible with the aqueous solution. The liquid crystal may include any liquid crystal composite material, such as, but not limited to, an NCAP material (e.g., a water-soluble polymer-based NCAP material or a latex polymer-based NCAP) or a PDLC material. The liquid crystal may form droplets that may include several molecules of the liquid crystal material.

[0051] In step 230, the liquid crystal material is emulsified within the polymer material. By emulsifying the liquid crystal material, the electrical properties of the liquid crystal material can be improved. The liquid crystal can form smaller droplets (about 1 to 10 microns in size) dispersed within the polymer material. When no electric field is applied, the liquid crystal molecules can be randomly oriented within the droplets. The liquid crystal / polymer material can be emulsified in any manner, such as (but not limited to) using mechanical force through a high-speed blade.

[0052] In step 240, the emulsified mixture is applied to the substrate. The emulsified mixture may be applied in a thin coating (about ten microns thick). For example, the thin coating may be applied by a spin coating process or the like.

[0053] In step 250, the film is dried. By drying the film, the water in the thin coating is evaporated. After the water evaporates, the liquid crystal remains dispersed in the polymer matrix. The liquid crystal molecules can be anchored to the polymer matrix. The degree of anchoring depends on the liquid crystal molecules and the polymer chemistry. When an electric field is applied in the liquid crystal material, the liquid crystal molecules and / or droplets can be aligned at least partially along the direction of the electric field. In order for the alignment to occur, the liquid crystal molecules and / or droplets overcome anchoring and / or friction with the polymer at the attachment location.

[0054] In an embodiment, the getter molecules may also be dispersed within the polymer matrix after the water evaporates. The getter molecules also getter cationic contamination that may be present within the polymer matrix. By getting rid of cationic contamination, electromagnetic shielding of the liquid crystal molecules may be reduced. Thus, the switching voltage of the membrane may be improved compared to an electro-optic modulator that does not contain the getter molecules. After the membrane is cured, the getter molecules may be present in the polymer matrix and easily collect nearby stray cations, effectively inhibiting the migration of the cations and neutralizing their charge. The ions are then no longer able to move under the AC electric field during modulator operation, where the effect is more pronounced as the frequency decreases, and the liquid crystal cannot be electrostatically shielded from switching.

[0055] It is further contemplated that each of the embodiments of the methods described above may include any other steps of any other method described herein. For example, it is contemplated that the gettering molecule may be added to the aqueous solution before, simultaneously with, or after the liquid crystal is added to the aqueous solution.

[0056] Figure 3 A conceptual view of an imaging system 300 is depicted according to one or more embodiments of the present disclosure. For the purposes of the present disclosure, the term 'imaging system' may be interchanged with the term 'imaging tool'. The imaging system 300 may generally include any type of imaging tool that is suitable, such as (but not limited to) voltage imaging. Voltage imaging may be used to detect and measure defects in a flat-panel thin-film transistor (TFT) array. The performance of the TFT array is generally simulated as if the TFT array were assembled into a TFT unit, and then the characteristics of the TFT array are measured by indirectly measuring the actual voltage distribution on the panel using an electro-optic modulator (e.g., electro-optic modulator 100), or so-called voltage imaging. Voltage imaging may be performed by the imaging system 300. The imaging system 300 may include one or more components for inspecting the TFT array or other samples.

[0057] Electro-optic modulator 100 can be advantageously used for a variety of imaging tasks, such as modulating the light source of imaging system 300 to assist in detecting one or more defects of sample 311, such as, but not limited to, a thin film transistor (TFT) array, a liquid crystal display (LCD) panel, and the like. The TFT array can be formed on a substrate, such as, but not limited to, a transparent thin glass plate. The TFT array can include one or more printed layers. The printed layers can be formed on the substrate by a variety of processes, such as, but not limited to, one or more material deposition steps, one or more photolithography steps, one or more etching steps, and the like. Fabrication can occur in stages, where materials, such as, for example, indium tin oxide (ITO), and the like, are deposited over previous layers or on a glass substrate according to a process pattern. During fabrication, the printed layers are fabricated within selected tolerances to properly construct the final device. The printed layers may exhibit defects that exceed the selected tolerances. Features of the TFT array can be measured by imaging system 300 to detect defects.

[0058] In an embodiment, the imaging system 300 includes an illumination source 306 to generate illumination 308. The illumination 308 may include one or more selected wavelengths of light, including, but not limited to, vacuum ultraviolet radiation (VUV), deep ultraviolet radiation (DUV), ultraviolet (UV) radiation, visible radiation, or infrared (IR) radiation. The illumination source 306 may further generate the illumination 308 to include any selected range of wavelengths. In an embodiment, the illumination source 306 may include a spectrally tunable illumination source to generate the illumination 308 having a tunable spectrum.

[0059] In an embodiment, the illumination source 306 directs illumination 308 to the sample 311 through an illumination path 309. The illumination path 309 may include one or more lenses 312 or additional illumination optical components 314 suitable for modifying and / or adjusting the illumination 308. For example, the one or more illumination optical components 314 may include, but are not limited to, one or more polarizers, one or more filters, one or more beam splitters, one or more diffusers, one or more homogenizers, one or more apodizers, one or more light straighteners, one or more gobos (e.g., mechanical gobos, electro-optic gobos, acousto-optic gobos, etc.), one or more aperture stops, and / or one or more field stops.

[0060] In an embodiment, the imaging system 300 includes an electro-optic modulator 100. The electro-optic modulator 100 can modulate one or more characteristics of the illumination 308. During operation, light is transmitted through a portion of the electro-optic modulator 100, and defects can be detected by observing changes in the reflected light or the transmitted light. The electro-optic modulator 100 can be placed at a selected number of microns (e.g., between 5 microns and 75 microns) above the surface of a sample 311 (e.g., a TFT array), and a voltage bias is applied in an indium tin oxide (hereinafter referred to as "ITO") layer transparent electrode on the surface of the electro-optic modulator 100. In addition, the electro-optic modulator 100 is capacitively coupled to the sample 311 so that the electric field associated with the sample 311 is sensed by one or more layers of the electro-optic modulator 100 (e.g., a layer including liquid crystal). The intensity of the incident light transmitted through the liquid crystal of the electro-optic modulator varies (i.e., modulated) based on the intensity of the electric field felt by the liquid crystal. For example, in the region where the normal pixels are located, a local voltage potential is applied (e.g., capacitive coupling between sample 311 and electro-optic modulator 100), thereby making one or more films of electro-optic modulator 100 locally translucent. In the locally translucent region, light from light source 306 is transmitted through electro-optic modulator 100 and reflected from sample 311 to be transmitted to collection path 322 (e.g., for capture by detector 304). By way of another example, in the region without an applied voltage potential (e.g., no capacitive coupling), one or more films of electro-optic modulator 100 remain locally opaque. In the case where electro-optic modulator 100 is locally opaque, light from light source 306 is scattered or otherwise prevented from being transmitted to sample 311. Therefore, a transmittance-voltage (TV) curve can be determined by applying a voltage. The intrinsic switching voltage of electro-optic modulator 100 can correspond to the voltage across electro-optic modulator 100 at which the light transmittance through electro-optic modulator 100 has the greatest sensitivity to voltage changes. For example, the switching voltage may correspond to an electric field strength at which a given percentage of the liquid crystal molecules are substantially aligned with the electric field, thereby allowing light transmission.

[0061] In an embodiment, sample 311 includes a thin film transistor (TFT) array. For example, sample 311 may include pixel elements disposed between inactive regions. Sample stage 318 may include any device suitable for positioning sample 311 within imaging system 300.

[0062] In an embodiment, the detector 304 is configured to capture radiation (e.g., sample light 320) that emanates from the sample 311 through a collection path 322. For example, the collection path 322 may include (but need not include) the electro-optic modulator 100, a collection lens (e.g., an objective lens), or one or more additional collection path lenses 324. In this regard, the detector 304 may receive radiation that is reflected or scattered from the sample 311 (e.g., by specular reflection, diffuse reflection, etc.) or generated by the sample 311 (e.g., luminescence associated with absorption of the illumination 308, etc.).

[0063] The system 300 may include, but is not limited to, a controller 303. The controller 303 may include one or more processors and memory, and may include or be coupled to a user interface 310.

[0064] The collection path 322 may further include any number of collection optical components 326 to direct and / or modify the illumination collected by the electro-optic modulator 100, including, but not limited to, one or more collection path lenses 324, one or more filters, one or more polarizers, or one or more blocks. In addition, the collection path 322 may include a field stop to control the spatial extent of the sample imaged onto the detector 304, or an aperture stop to control the angular extent of the illumination from the sample used to produce the image on the detector 304. In another embodiment, the collection path 322 includes an aperture stop located in a plane conjugate to the back focal plane of the optical element to provide telecentric imaging of the sample. In an embodiment, the imaging system 300 includes a beam splitter 328, which is oriented so that the electro-optic modulator 100 can simultaneously direct the illumination 308 to the sample 311 and collect radiation diverging from the sample 311.

[0065] The detector 304 may include any type of optical detector suitable for measuring the illumination received from the sample 311. For example, the detector 304 may include, but is not limited to, a CCD detector, a TDI detector, a photomultiplier tube (PMT), a photoavalanche diode (APD), a complementary metal oxide semiconductor (CMOS) sensor, etc. In another embodiment, the detector 304 may include a spectral detector suitable for identifying the wavelength of light emitted from the sample 311.

[0066] In an embodiment, the controller 303 is communicatively coupled to the detector 304. The controller 303 may include one or more processors configured to perform any of the various process steps. In an embodiment, the controller 303 is configured to generate and provide one or more control signals configured to make one or more adjustments to one or more processing tools based on the image signal 313 from the detector 304.

[0067] The one or more processors of the controller 303 may include any processor or processing element known in the art. For the purposes of the present disclosure, the term "processor" or "processing element" may be broadly defined to encompass any device having one or more processing or logic elements (e.g., one or more microprocessor devices, one or more application specific integrated circuit (ASIC) devices, one or more field programmable gate arrays (FPGAs), or one or more digital signal processors (DSPs)). In this sense, the one or more processors may include any device configured to execute algorithms and / or instructions (e.g., program instructions stored in a memory). In one embodiment, the one or more processors may be embodied as a desktop computer, a mainframe computer system, a workstation, an image computer, a parallel processor, a networked computer, or any other computer system configured to execute a program configured to operate or operate with the imaging system 300, as described throughout the present disclosure. In addition, different subsystems of the system 300 may include processors or logic elements suitable for performing at least a portion of the steps described in the present disclosure. Therefore, the above description should not be construed as limiting the embodiments of the present disclosure, but only as an illustration. Additionally, the steps described throughout the present disclosure may be performed by a single controller or, alternatively, multiple controllers. Additionally, the controller 303 may include one or more controllers housed in a common housing or multiple housings. In this manner, any controller or combination of controllers may be separately packaged as a module suitable for integration into the imaging system 300. Additionally, the controller 303 may analyze the data received from the detector 304 and feed the data to additional components within the imaging system 300 or external to the imaging system 300.

[0068] The memory medium may include any storage medium known in the art suitable for storing program instructions that can be executed by the associated one or more processors. For example, the memory medium may include a non-transitory memory medium. By way of another example, the memory medium may include, but is not limited to, a read-only memory (ROM), a random access memory (RAM), a magnetic or optical memory device (e.g., a disk), a tape, a solid-state hard drive, etc. It should be further noted that the memory medium may be housed in a common controller housing with one or more processors. In one embodiment, the memory medium may be remotely located relative to the physical location of the one or more processors and the controller. For example, one or more processors of the controller 303 may access a remote memory (e.g., a server) that may be accessed through a network (e.g., the Internet, an intranet, etc.).

[0069] In an embodiment, the user interface 310 is communicatively coupled to the controller 303. In an embodiment, the user interface 310 may include, but is not limited to, one or more desktop computers, laptop computers, tablet computers, etc. In an embodiment, the user interface 310 includes a display for displaying data of the system 300 to the user. The display of the user interface 310 may include any display known in the art. For example, the display may include, but is not limited to, a liquid crystal display (LCD), a display based on an organic light emitting diode (OLED), or a CRT display. Those skilled in the art will recognize that any display device capable of being integrated with the user interface 310 is suitable for implementation in the present disclosure. In an embodiment, the user may enter a selection and / or instruction through a user input device of the user interface 310 in response to the data displayed to the user.

[0070] Generally speaking, refer again Figures 1A to 3 , while the getter molecules have been described as being added to an electro-optic modulator of an imaging system, this is not intended to be a limitation of the present disclosure. Upon further consideration, the getter molecules may be added to a variety of water-based polymers. By adding the getter molecules to the water-based polymers, the dielectric properties of the water-based polymers may be improved. For example, current leakage or dielectric loss of the water-based polymers may be a concern. By adding the getter molecules, the dielectric properties of the water-based polymers, such as capacitance, may be improved. Thus, the getter molecules may address issues associated with free cations, such as capacitance or fouling. The water-based polymers may include a variety of beneficial applications, such as smart window technology, sensors or other nematic curved alignment phase liquid crystal (NCAP) films. In solvent-based systems, polymer dispersed liquid crystal (PDLC) films, polymer stabilized liquid crystals (PSLC) may be similarly improved.

[0071] Defect removal can be beneficial in a variety of polymeric compositions. The polymeric composition may include a polymer matrix formed by crosslinking a plurality of polymer molecules. The polymeric composition may also include defect removal molecules dispersed within the polymer matrix. The defect removal molecules and the polymer matrix may each be soluble in a solvent, such as, but not limited to, water. Each of the defect removal molecules may include a cation and an anion. The anion may be configured to remove defects from one or more cationic impurities disposed within the polymer matrix. In an embodiment, the defect removal molecule comprises 0.01 to 1.0 weight percent of the polymer matrix, although this is not intended to be limiting. In an embodiment, the anion comprises at least one of phosphate, carboxylate, sulfate, carbonate, thiosulfate, sulfite, acetate, or borate. In an embodiment, the cation is one of hydrogen, ammonium, hydronium, or an organic group. In an embodiment, the plurality of defect removal molecules is at least one of nicotinic acid, nicotinate, ethylenediaminetetraacetic acid (EDTA), ammonium dihydrogen phosphate, polystyrene sulfonic acid, polystyrene sulfonate, or valinomycin. The defect removal molecule may include a pKa value between 0 and 3, although this is not intended to be limiting.

[0072] The modulator material layer may include a polymer matrix and liquid crystals dispersed within the polymer matrix. The intrinsic switching voltage of the liquid crystal may correspond to the voltage in the modulator material layer at which the light transmittance through the electro-optic modulator has the greatest sensitivity to voltage changes. The sensitivity may be improved by reducing the intrinsic switching voltage of the liquid crystal material. The operating voltage and sensitivity of the liquid crystal material may be related to one or more factors, such as (but not limited to) the properties of the liquid crystal, the properties of the polymer matrix, the liquid crystal droplet size distribution in the polymer matrix, and / or the interface properties between the polymer matrix and the liquid crystal.

[0073] The modulator material layer may include one or more classes of materials. Liquid crystal / polymer composite materials may generally be divided into the class of polymer dispersed liquid crystal (PDLC) materials and the class of nematic curved alignment phase liquid crystal (NCAP) materials. Each of the PDLC materials and NCAP materials may generally include liquid crystal droplets dispersed within a polymer matrix.

[0074] PDLC materials or films can be manufactured in a variety of ways. For example, PDLC materials can be manufactured by solvent-induced phase separation (SIPS). The SIPS process can include dissolving liquid crystal (LC) and polymer in a common solvent and then evaporating the solvent to form LC droplets. It is also possible to select a decontamination molecule so that it is soluble in a common solvent. In some examples, the solvent is water, although this is not intended to be limiting. To further improve the mechanical properties (e.g., toughness) of the final PDLC film, a cross-linkable polymer is generally used. By way of another example, PDLC materials can be manufactured by polymerization-induced phase separation (PIPS). The PIPS process can include mixing LC and prepolymers (and / or monomers) and applying radiation (e.g., ultraviolet light) to the mixture. The PIPS process can also include a mixture of a catalyst, LC, and a prepolymer, and then heating to form a PDLC film. By way of another example, PDLC materials can be manufactured by thermally induced phase separation (TIPS). The TIPS process can include heating a mixture of a polymer and LC until the mixture becomes uniform. Then the LC is separated from the polymer during the cooling process.

[0075] NCAP materials or films can be used to make very large area light valves and displays. NCAP materials or films are typically water-based and can be further divided into multiple subcategories. For example, one subcategory of NCAP materials includes water-soluble polymers, such as polyvinyl alcohol (PVA) or urethane. Water-soluble polymers can be moisture-sensitive due to the hydrophilic properties of water-soluble polymers. By way of another example, one subcategory of NCAP materials includes latex-based materials. Latex-based materials include water-insoluble polymers. Latex particles can be dispersed in water together with liquid crystals. These latex particles can "fuse" into a continuous polymer phase that is irreversible once the water is removed. Some applications using latex-based NCAPs have long-term electro-optical stability.

[0076] The liquid crystal material may include any liquid crystal material. For example, the liquid crystal may include, but is not limited to, one or more of the following: nematic liquid crystal, ferroelectric liquid crystal, blue phase liquid crystal, a mixture of liquid crystal and dichroic dye, cholesteric liquid crystal, etc. For dichroic dyes and liquid crystal mixtures, the dichroic dye may absorb light in the off state and transmit light in the on state, which will improve the light transmission voltage sensitivity by using a slope corresponding to the s-curve with a higher light intensity. The liquid crystal material may be substantially hydrophobic so that droplets of the liquid crystal material can be formed from the emulsion, and so that the prepolymer and the photoinitiator can be substantially soluble in the liquid crystal droplets. The prepolymer and the photoinitiator may be substantially hydrophobic so that the liquid crystal droplets of the emulsion include a majority of the photoinitiator and the prepolymer mixture.

[0077] The polymer matrix material may include any polymer material. For example, the polymer matrix material may include, but is not limited to, one or more water-based polymers, such as polyvinyl alcohol (PVA) or urethane; or a water-based latex, such as Neorez R-967 (manufactured by NeoResins, a division of DSM). The amount of the polymer matrix material may correspond to the strength and stiffness of the sensor material. The weight ratio of the liquid crystal material to the polymer matrix material may be in the range of, for example, about 50 / 50 to about 80 / 20. Increasing the amount of the polymer matrix material may increase the strength and operating voltage of the sensor material. The polymer matrix may be soluble in water to form an aqueous mixture. During the formation of the modulator material layer 108, one or more surfactants (e.g., wetting agents) may be added to the aqueous mixture. The surfactant may improve the ability of the modulator material layer 108 to expand due to reduced surface tension.

[0078] As used throughout this disclosure, the term "sample" generally refers to a substrate formed of a semiconductor or non-semiconductor material (e.g., thin film glass, etc.). For example, the semiconductor or non-semiconductor material may include, but is not limited to, single crystal silicon, gallium arsenide, indium phosphide, or glass material. The sample may include one or more layers. For example, the layer may include, but is not limited to, a resist (including a photoresist), a dielectric material, a conductive material, and a semiconductor material. Many different types of such layers are known in the art, and the term sample as used herein is intended to cover samples on which all types of such layers may be formed. One or more layers formed on the sample may be patterned or unpatterned. For example, a sample may include a plurality of dies, each of which has repeatable patterned features. The formation and processing of the material layers may ultimately produce a complete device. Many different types of devices may be formed on the sample, and the term sample as used herein is intended to cover samples on which any type of device known in the art is manufactured. In addition, for the purposes of this disclosure, the terms sample and wafer should be interpreted as interchangeable. Additionally, for the purposes of this disclosure, the terms patterning device, mask, and reticle should be interpreted interchangeably.

[0079] Upon further consideration, each of the embodiments of the method described above may include any other steps of any other method described herein. In addition, each of the embodiments of the method described above may be performed by any of the systems described herein.

[0080] Those skilled in the art will recognize that the components, operations, devices, objects, and accompanying discussions described herein are used as examples for the sake of conceptual clarity, and various configuration modifications are contemplated. Therefore, as used herein, the specific examples and accompanying discussions set forth are intended to represent their more general class. In general, the use of any specific example is intended to represent its class, and the failure to include specific components, operations, devices, and objects should not be considered limiting.

[0081] As used herein, directional terms such as "top", "bottom", "above", "below", "upper", "upward", "lower", "downward", and "downward" are intended to provide relative positions for descriptive purposes and are not intended to specify absolute reference coordinates. Various modifications to the described embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments.

[0082] With respect to the use of substantially any plural and / or singular terms herein, those skilled in the art may interpret the plural as singular and / or the singular as plural as appropriate to the context and / or application. For clarity, various singular / plural arrangements are not explicitly set forth herein.

[0083] The subject matter described herein sometimes depicts different components contained in or connected to other components. It should be understood that the depicted architecture is only exemplary, and many other architectures that achieve the same functionality can actually be implemented. In a conceptual sense, any arrangement of components that achieve the same functionality is effectively "associated" to achieve the desired functionality. Therefore, any two components combined to achieve a specific functionality herein can be considered to be "associated" with each other so that the desired functionality is achieved, regardless of the architecture or intermediate components. Similarly, any two components so associated can also be considered to be "connected" or "coupled" to each other to achieve the desired functionality, and any two components that can be so associated can also be considered to be "coupleable" to each other to achieve the desired functionality. Specific examples that can be coupled include (but are not limited to) physically matable and / or physically interactive components, and / or wirelessly interactive and / or wirelessly interactive components, and / or logically interactive and / or logically interactive components.

[0084] In addition, it should be understood that the present invention is defined by the appended claims. It should be understood by those skilled in the art that, in general, the terms used herein and particularly in the appended claims (e.g., the body of the appended claims) are generally intended to be "open" terms (e.g., the term "including" should be interpreted as "including (but not limited to)", the term "having" should be interpreted as "at least having", the term "includes" should be interpreted as "including (but not limited to)", etc.). It should be further understood by those skilled in the art that if it is intended to specify a specific number of the introduced technical solution descriptions, then the intention will be clearly stated in the technical solution, and the intention does not exist in the absence of the description. For example, as an aid to understanding, the following appended claims may contain the use of the introductory phrases "at least one" and "one or more" to introduce the technical solution descriptions. However, the use of the phrase should not be understood to imply that the introduction of a claim by the indefinite article "a" or "an" limits any particular claim containing the introduced claim to inventions containing only one of the claims, even when the same claim includes the introductory phrase "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" are typically interpreted as meaning "at least one" or "one or more"); the same applies to the use of definite articles to introduce a claim. Furthermore, even if a specific number of introduced claims is explicitly recited, those skilled in the art will recognize that the recitation is typically interpreted as meaning at least the recited number (e.g., the unmodified recitation of "two claims" in the absence of other modifiers typically means at least two claims or two or more claims). Furthermore, where conventional language similar to “at least one of A, B, and C, etc.” is used, generally speaking, the structure is intended to be understood by those skilled in the art for the meaning of the conventional language (e.g., “a system having at least one of A, B, and C” would include, but is not limited to, systems having A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). Where conventional language similar to “at least one of A, B, or C, etc.” is used, generally speaking, the structure is intended to be understood by those skilled in the art for the meaning of the conventional language (e.g., “a system having at least one of A, B, or C” would include, but is not limited to, systems having A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.).Those skilled in the art will further understand that, whether in the description, claims or drawings, virtually any disjunctive word and / or phrase presenting two or more alternative terms should be understood to contemplate the possibility of including one of the terms, any one of the terms, or both of the terms. For example, the phrase "A or B" should be understood to include the possibility of "A" or "B" or "A and B".

[0085] It is believed that the present disclosure and its many attendant advantages will be understood from the foregoing description, and it is apparent that various changes may be made to the form, construction and arrangement of components without departing from the disclosed subject matter or sacrificing all of its substantial advantages. The described form is illustrative only, and the following claims are intended to cover and include such changes. Furthermore, it should be understood that the invention is defined by the appended claims.

Claims

1. An electro-optic modulator, comprising: a polymer matrix, which is formed by cross-linking a plurality of polymer molecules; a plurality of liquid crystal molecules dispersed in the polymer matrix; and a plurality of getter molecules dispersed within the polymer matrix, wherein the plurality of getter molecules and the polymer matrix are each soluble in a solvent, wherein the plurality of getter molecules are insoluble in the plurality of liquid crystal molecules, wherein each of the plurality of getter molecules comprises a cation and an anion configured to getter one or more cationic impurities disposed within the polymer matrix.

2. The electro-optic modulator of claim 1, wherein the solvent comprises water, wherein the electro-optic modulator comprises a nematic curve alignment phase (NCAP) film, wherein the plurality of getter molecules comprises a pKa value between 0 and 3. The electro-optic modulator of claim 1 , wherein the anion comprises a carboxylate group.

4. The electro-optic modulator of claim 3, wherein the plurality of getter molecules comprise one of nicotinic acid or a nicotinic acid salt.

5. The electro-optic modulator of claim 3, wherein the plurality of getter molecules comprises ethylenediaminetetraacetic acid (EDTA).

6. The electro-optic modulator of claim 1, wherein the anion comprises a phosphate group.

7. The electro-optic modulator of claim 6, wherein the plurality of getter molecules comprise dihydrogen phosphate.

8. The electro-optic modulator of claim 7, wherein the plurality of getter molecules comprises diammonium phosphate.

9. The electro-optic modulator of claim 1, wherein the anion comprises a sulfonate group.

10. The electro-optic modulator of claim 9, wherein the plurality of getter molecules comprises one of polystyrene sulfonic acid or polystyrene sulfonate.

11. The electro-optic modulator of claim 1, wherein the plurality of getter molecules contain a chelating agent.

12. The electro-optic modulator of claim 1, wherein the plurality of defect-gettering molecules comprises valinomycin.

13. The electro-optic modulator of claim 1, wherein the plurality of getter molecules comprise 0.01 to 1.0 weight percent of the polymer matrix.

14. The electro-optic modulator of claim 1, wherein the polymer matrix, the plurality of liquid crystal molecules, and the plurality of getter molecules form a modulator material layer.

15. The electro-optic modulator of claim 14, further comprising a glass substrate, wherein the modulator material layer is one of a direct coating on the glass substrate or a stack of layers on the glass substrate.

16. The electro-optic modulator of claim 15, further comprising a dielectric mirror film laminated on top of the modulator material layer, wherein the plurality of liquid crystal molecules are configured to align for selectively modulating light in response to receiving a voltage through the dielectric mirror film.

17. The electro-optic modulator of claim 1, wherein the anion comprises at least one of phosphate, carboxylate, sulfate, carbonate, thiosulfate, sulfite, acetate, or borate.

18. The electro-optic modulator of claim 1, wherein the cation is one of hydrogen, ammonium, hydronium, or an organic radical.

19. The electro-optic modulator of claim 18, wherein the ammonium is configured to passivate trap states of the polymer matrix, thereby reducing a threshold field or hysteresis for switching the plurality of liquid crystals.

20. An imaging system comprising: an illumination source configured to generate illumination; a support for the sample; an electro-optic modulator disposed in a path of the illumination from the illumination source and separated from the sample by an air gap, wherein the electro-optic modulator comprises: polymer matrix; a plurality of liquid crystal molecules dispersed in the polymer matrix; and a plurality of getter molecules dispersed within the polymer matrix, wherein the plurality of getter molecules and the polymer matrix are each soluble in a solvent, wherein the plurality of getter molecules are insoluble in the plurality of liquid crystal molecules, wherein each of the plurality of getter molecules comprises a cation and an anion configured to getter one or more cationic impurities of the polymer matrix; as well as A detector is used to generate an image of at least a portion of the sample.

21. A method of manufacturing an electro-optic modulator, the method comprising: adding a plurality of defect-removing molecules to a solution including a plurality of polymer molecules dissolved in a solvent; adding a plurality of liquid crystal molecules to the solution; emulsifying the plurality of liquid crystal molecules in the solution to disperse the plurality of liquid crystal molecules, thereby forming a mixture; coating a substrate with the mixture to form a film; and and drying the film, wherein the film comprises: a polymer matrix formed by the plurality of polymer molecules; The plurality of liquid crystal molecules are dispersed in the polymer matrix; and The plurality of defect-getter molecules are dispersed in the polymer matrix, wherein the plurality of defect-getter molecules are soluble in the solvent, wherein the plurality of defect-getter molecules are insoluble in the plurality of liquid crystal molecules, wherein each of the plurality of defect-getter molecules comprises a cation and an anion configured to getter one or more cationic impurities of the polymer matrix.

22. A polymeric composition comprising: a polymer matrix formed by cross-linking a plurality of polymer molecules; and a plurality of defect-getting molecules dispersed within the polymer matrix, wherein the plurality of defect-getting molecules and the polymer matrix are each soluble in a solvent, wherein the solvent comprises water, wherein each of the plurality of defect-getting molecules comprises a cation and an anion configured to get rid of one or more cationic impurities disposed within the polymer matrix.

23. The polymeric composition of claim 22, wherein the anion comprises at least one of: phosphate, carboxylate, sulfate, carbonate, thiosulfate, sulfite, acetate, or borate; wherein The cation includes at least one of hydrogen, ammonium, hydronium, or an organic group.

24. The polymeric composition of claim 23, wherein the plurality of defect-removing molecules comprises at least one of nicotinic acid, a nicotinic acid salt, ethylenediaminetetraacetic acid (EDTA), diammonium phosphate, polystyrene sulfonic acid, a polystyrene sulfonate, or valinomycin.

25. The polymeric composition of claim 24, wherein the plurality of gettering molecules comprise 0.01 to 1.0 weight percent of the polymer matrix.

26. The polymeric composition of claim 22, wherein the plurality of gettering molecules comprises a pKa value between 0 and 3.

Images