Patent ID: 12189161

DEFINITIONS

As used herein, the term “contrast” means a fraction of transmission through the WGP of the predominantly transmitted polarization (e.g. Tp) divided by a fraction of transmission through the WGP of an opposite polarization (e.g. Ts). For example, contrast=Tp/Ts.

As used herein, the term “longitudinal dimension” means a longest dimension of the polarization structures12parallel to the first side11of the substrate11.

As used herein, the term “metal atoms” includes both true metals as well as metalloids, such as for example silicon and germanium.

As used herein, the term “nanometer-sized” means dimensions of ≤1000 nm.

As used herein, the term “nanoparticles” means particles with a width or diameter of ≤1000 nm. The nanoparticles can have a width or diameter of ≤500 nm, ≤100 nm, ≤50 nm, or ≤10 nm if explicitly so stated in the claims. The aforementioned width or diameter can be a largest width or diameter of all the nanoparticles if explicitly so stated in the claims. The nanoparticles can also have a width or diameter of ≥0.1 nm, ≥1 nm, or ≥5 nm if explicitly so stated in the claims. The aforementioned width or diameter can be a smallest width or diameter of all the nanoparticles if explicitly so stated in the claims.

As used herein, the term “nm” means nanometer(s) and the term “mm” means millimeter(s).

As used herein, the terms “on”, “located on”, “located at”, and “located over” mean located directly on or located over with some other solid material between. The terms “located directly on”, “adjoin”, “adjoins”, and “adjoining” mean direct and immediate contact with no other solid material between.

As used herein, the term “perpendicular” means exactly perpendicular or within 20 degrees of exactly perpendicular.

As used herein, the term “pixels” means different regions of an optical device with intentionally different optical properties.

As used herein, the term “parallel” means exactly parallel, parallel within normal manufacturing tolerances, or nearly parallel, such that any deviation from exactly parallel would have negligible effect for ordinary use of the device.

As used herein, the term “rpm” means revolutions per minute.

Materials used in optical structures can absorb some light, reflect some light, and transmit some light. The following definitions distinguish between materials that are primarily absorptive, primarily reflective, or primarily transparent. Each material can be considered to be absorptive, reflective, or transparent in a specific wavelength range (e.g. ultraviolet, visible, or infrared spectrum) and can have a different property in a different wavelength range. Thus, whether a material is absorptive, reflective, or transparent is dependent on the intended wavelength range of use. Materials are divided into absorptive, reflective, and transparent based on reflectance R, the real part of the refractive index n, and the imaginary part of the refractive index/extinction coefficient k. Equation 1 is used to determine the reflectance R of the interface between air and a uniform slab of the material at normal incidence:

R=(n-1)2+k2(n+1)2+k2Equation⁢1

Unless explicitly specified otherwise herein, materials with k≤0.1 in the specified wavelength range are “transparent” materials, materials with k>0.1 and R≤0.6 in the specified wavelength range are “absorptive” materials, and materials with k>0.1 and R>0.6 in the specified wavelength range are “reflective” materials.

DETAILED DESCRIPTION

First Method—Cover Layer34/44on Overcoat Layer14

As illustrated inFIGS.1-9, a first method of making a polarizer can comprise some or all of the following steps, which can be performed in the following order. There may be additional steps not described below. These additional steps may be before, between, or after those described.

As illustrated inFIG.1, one step10in the first method can include providing a polarization device15on a substrate11. The substrate11can be transparent. The polarization device15can include objects or materials arranged in a pattern for polarization of light. For example, the polarization device15can be an array of parallel wires as the polarization structures12as shown inFIG.2, polarization structures12extending in different directions such as is shown inFIGS.19-21, or a film polarizer.

An overcoat layer14can be applied or located on a surface15of the polarization device15farthest from the substrate11. The overcoat layer14can be a single layer of a single material or can be multiple layers of different materials. The overcoat layer14can be sputtered onto the polarization device15, applied by atomic layer deposition, or other method. The overcoat layer14can be applied as described in patent publication US 2010/0103517.

If the polarization device15includes an array of wires with channels13between adjacent wires, the overcoat layer14can extend into the channels13and can fill the channels13. Alternatively, the channels13can be free of the overcoat layer14. The channels13can be partially filled with the overcoat layer14, such as for example ≥10% filled, ≥25% filled, or ≥40% filled, and can be ≤60% filled, ≤80% filled, or ≤90% filled.

A schematic perspective-view of a polarizer20is illustrated inFIG.2, with elongated wires on a substrate11, in accordance with an embodiment of the present invention. The polarization structures12of the various embodiments described herein can be similarly elongated. As used herein, the term “elongated” means that a length L12of the wires is substantially greater than wire width W12or wire thickness Th12(e.g. L12can be ≥10 times, ≥100 times, ≥1000 times, or ≥10,000 times larger than wire width W12and/or wire thickness Th12). For example, L12can be ≥1 mm or ≥10 mm, W12can be ≤200 nm or ≤100 nm, and Th12can be ≤500 nm or ≤1000 nm.

As illustrated inFIG.3, another step30in the first method can be applying an uncured cover layer34to an outer surface14sof the overcoat layer14farthest from the polarization device15. Step30can follow step10.

As illustrated inFIG.5, the substrate11can be a first substrate11a. The first method can further comprise step50, placing a second substrate11bonto the uncured cover layer34. Step50can follow step30.

As illustrated inFIGS.7-8, other steps70and80in the first method can include imprinting a pattern of structures84in the uncured cover layer34. A stamp55can imprint the structures84in the uncured cover layer34. The structures84can be sized and shaped to reduce reflection of incident light, to increase heat transfer away from the polarizer, or both. For example, the structures84can be shaped like ribs or pillars to increase surface area for heat transfer, to reduce reflection, or both. Steps70and80can follow step30.

As illustrated inFIGS.4,6, and9, steps40,60, and90respectively in the first method can include curing (i.e. causing a chemical reaction in) the uncured cover layer34to form a cured cover layer44. Characteristics of the uncured cover layer34, characteristics of the cured cover layer44, and curing are described below in the Added Features Applicable to All Methods section. Step40can follow step30, step60can follow step50, and step90can follow step80.

If the polarization device15includes channels13between adjacent polarization structures12, it can be difficult to manufacture the overcoat layer14with sufficient integrity to keep the uncured cover layer34, and thus also the cured cover layer44, out of the channels13. If the uncured cover layer34enters only some of the channels13, tensile forces in the uncured cover layer34, in the cured cover layer44, or both can cause polarization structures12to topple, thus impairing polarization. Also, polarization will not be uniform across the polarizer if the cured cover layer44is in only some of the channels13.

One way to keep the uncured cover layer34out of the channels13is to select chemistry of the uncured cover layer34that is repellant with respect to chemistry of all of, or at least the outer surface14sof, the overcoat layer14. A material for the overcoat layer14or for the outer surface14sof the overcoat layer14can have a relatively low surface energy and a solvent of the uncured cover layer34can have a relatively high surface tension. The surface tension of the uncured cover layer34can be greater than the surface energy of the outer surface14sof the overcoat layer14. For example, if the uncured cover layer34includes water as a solvent, then the outer surface14of the overcoat layer14can include a hydrophobic coating. Another way to keep the uncured cover layer34out of the channels13is to use larger nanoparticles.

Proper selection of chemistry of the uncured cover layer34and of the outer surface14s, and large nanoparticle size, can result in channels13between adjacent polarization structures12that are free of the uncured cover layer34and free of the cured cover layer44, or that are nearly free of the uncured cover layer34and the cured cover layer44. For example, ≥98%, ≥99%, or ≥99.9% of a total volume of the channels13can be free of the uncured cover layer34and the cured cover layer44.

A polarizer made from the first method can have some or all of the following characteristics: high contrast (e.g. Tp/Ts), ability to endure a high temperature, resistant to physical damage, and relatively easy to manufacture.

Second Method—Fill Layer134/144in Channels13

As illustrated inFIGS.10a-17, a second method of making a polarizer can comprise some or all of the following steps, which can be performed in the following order. There may be additional steps not described below. These additional steps may be before, between, or after those described.

As illustrated inFIG.10a, one step10in the second method can be providing a polarizer. The polarizer can include polarization structures12on a substrate11. The substrate11can be transparent. The polarization structures12can be arranged in a pattern for polarization of light. For example, the polarization structures12can be an array of parallel, elongated wires with channels13between adjacent wires. Alternately, the polarization structures12can extend in different directions as described below and shown inFIGS.19-21. The polarization structures12can have a proximal end12pcloser to the substrate11and a distal end12dfarther from the substrate11. The polarization structures12can include materials for polarization of light.

As illustrated inFIG.10b, polarizer100bis shown with the polarization structures12comprising an array of wires, each wire including a reflective wire102and an absorptive rib101. On polarizer100b, the reflective wire102is sandwiched between the absorptive rib101and the substrate11. An opposite order, with the absorptive rib101sandwiched between the reflective wire102and the substrate11, is within the scope of the inventions herein. The polarization structures12of any of the methods described herein can include a reflective wire102and an absorptive rib101, however, this embodiment might be particularly suited to the second method if the cured cover layer44is used as a heat sink or for heat transfer of heat away from the polarization structures12.

As illustrated inFIG.11a, another step110ain the second method can be applying an uncured fill layer134on top of the polarization structures12and extending into channels13between the polarization structures12. Step110acan follow step100a. Step110acan use polarizer100b.

As illustrated inFIG.11b, another step110bin the second method can be applying an uncured fill layer134in channels13between the polarization structures12but not on top of the polarization structures12. Step110bcan follow step100a. Step110bcan use polarizer100b.

As illustrated inFIGS.14-15, other steps140and150in the second method can include imprinting a pattern of structures84in the uncured fill layer134. A stamp55can be used to imprint the structures84. The structures84can be sized and shaped to reduce reflection of incident light, to increase heat transfer away from the polarizer, or both. For example, the structures84can be shaped like ribs or pillars to increase surface area for heat transfer, to reduce reflection, or both. Steps140and150can follow step110.

As illustrated inFIG.16, the substrate11can be a first substrate11a. The second method can further comprise step160, placing a second substrate11bonto the uncured fill layer134. Step160can follow step110.

As illustrated inFIGS.12a,12b,15, and17, steps120a,120b,150, and170respectively in the second method can include curing (i.e. causing a chemical reaction in) the uncured fill layer134to form a cured fill layer144. Characteristics of the uncured fill layer134, characteristics of the cured fill layer144, and curing are described below in the Added Features Applicable to All Methods section. Step120acan follow step110a, step120bcan follow step110b, step150can follow step140, and step170can follow step160.

In the second method, complete, or nearly complete, filling the channels13with the cured fill layer144can be a consideration for optical properties of the polarizer and can be a consideration for structural support of the polarization structures12. For example, the cured fill layer144can fill ≥75%, ≥90%, ≥95%, or ≥98% of the channels13.

Filling the channels with the uncured fill layer134facilitates filling the channels with the cured fill layer144. One way to help fill the channels13is to select chemistry of the uncured fill layer134that is attractive with respect to chemistry of an outer surface of the polarization structures12. For example, the uncured fill layer134can be primarily an aqueous solution and the outer surface of the polarization structures12can be hydrophilic, such as an oxide. A material for the outer surface of the polarization structures12can have a relatively high surface energy and a solvent of the uncured fill layer134can have a relatively low surface tension. The surface energy of the outer surface of the polarization structures12can be greater than the surface tension of the uncured fill layer134. For example, the surface energy of the surface of the polarization structures12can be two times greater than, five times greater than, or ten times greater than the surface tension of the uncured fill layer134. For example, if the uncured fill layer134includes water as a solvent, then the outer surface of the polarization structures12can include a hydrophilic coating. Another way to help fill the channels13with the uncured fill layer134is to use smaller nanoparticles.

A polarizer made from the second method can have some or all of the following characteristics: high contrast (e.g. Tp/Ts), ability to endure a high temperature, resistant to physical damage, and be relatively easy to manufacture. This embodiment can be particularly helpful for high temperature endurance due to the cured fill layer144in the channels13—the cured fill layer144can be an effective heat sink or heat transfer path to draw heat away from the polarization structures12.

Third Method—Imprintable Layer184and Printed Layer204

As illustrated inFIGS.18-21, a third method of making a polarizer can comprise some or all of the following steps, which can be performed in the following order. There may be additional steps not described below. These additional steps may be before, between, or after those described.

As illustrated inFIG.18, one step180in the third method can include providing a substrate11that is transparent. An uncured imprintable layer184can be applied to a first side11of the substrate11. As illustrated inFIGS.18-19, steps180and190in the third method can include imprinting a pattern of polarization structures12in the uncured imprintable layer184.

As illustrated inFIG.20, another step200in the method can include curing (i.e. causing a chemical reaction in) the uncured imprintable layer184to form a cured printed layer204. Characteristics of the uncured imprintable layer184, characteristics of the cured printed layer204, and curing are described below in the Added Features Applicable to All Methods section. Step200can follow step190.

Characteristics of the polarization structures12are shown inFIGS.19-21and can include the following: A longitudinal dimension L of some of the polarization structures12can extend in a first direction D1. A longitudinal dimension L of other of the polarization structures12can extend in a second direction D2. The first direction D1and the second direction D2can be parallel to the first side11rof the substrate11. The first direction D1can be a different direction from the second direction D2. The first direction D1can be perpendicular to the second direction D2. A longitudinal dimension L of some of the polarization structures12can extend in at least three different directions or at least four different directions.

The polarization structures12can have a width W that is perpendicular to the longitudinal dimension L and parallel to the first side11fof the substrate11. The width W of at least some of the polarization structures12extending in the first direction D1and a width W of at least some of the polarization structures12extending in the second direction D2can be ≤100 nm, ≤500 nm, or ≤1000 nm.

The polarization structures12can have multiple, different thicknesses Th. The thickness Th is a dimension perpendicular to the first side11fof the substrate11. For example, the polarization structures can have a ≥two, ≥three, ≥four, or ≥five different thicknesses Th. Each of these different thicknesses Th can differ from each other, such as for example by ≥5 nm, ≥10 nm, ≥20 nm, or ≥40 nm and/or by ≤60 nm, ≤120 nm, or ≤500 nm.

The substrate11and the polarization structures12can be made of the same material. For example, the substrate11and the polarization structures12can both be dielectric. A material composition of the substrate11and of the polarization structures12can be or can include glass.

One distinct characteristic of the polarizer of the third method is the ability to transmit ≥50% of incident unpolarized light as a single polarization. For example, this polarizer can transmit ≥50%, ≥60%, ≥70%, or ≥80%, of incident light as a single polarization.

Examples of an extinction ratio of the polarizer of the third method can be ≥2, ≥3, ≥5, or ≥10. The extinction ratio means an amount of incident light transmitted as a predominantly-transmitted polarization divided by an amount of the incident light transmitted as an opposite polarization.

A polarizer made from the third method can have a high percent transmission of one polarization and can be relatively easy to manufacture.

Fourth Method—Backside Layer234/244

As illustrated inFIGS.22-24, a fourth method of making a polarizer can comprise some or all of the following steps, which can be performed in the following order. There may be additional steps not described below. These additional steps may be before, between, or after those described.

As illustrated inFIG.22, one step220in the fourth method can include providing a polarizer with a substrate11having a first side11fand a second side11sopposite of the first side11f. The substrate11can be transparent. A polarization device15can be located on the first side11fof the substrate11. The polarization device15can include objects or materials arranged in a pattern for polarization of light. The polarization device15can be any described herein or other type of polarizer.

As illustrated inFIGS.22-23, steps220and230in the fourth method can include applying an uncured backside layer234to the second side11sof the substrate11and imprinting a pattern of structures84in the uncured backside layer234. A stamp55can be used to imprint the structures84. The structures84can be sized and shaped to reduce reflection of incident light, to increase heat transfer away from the polarizer, or both. For example, the structures84can be shaped like ribs or pillars to increase surface area for heat transfer, to reduce reflection, or both.

As illustrated inFIG.24, another step240in the fourth method can include curing (i.e. causing a chemical reaction in) the uncured backside layer234to form a cured backside layer244. Characteristics of the uncured backside layer234, characteristics of the cured backside layer244, and curing are described below in the Added Features Applicable to All Methods section. Step240can follow step230.

A polarizer made from the fourth method can have some or all of the following characteristics: a high percent transmission of one polarization, ability to endure a high temperature due to the imprinted structures84, and relatively easy to manufacture.

Fifth Method—Thin Films251/261

As illustrated inFIGS.25-35, a fifth method of making a polarizer can comprise some or all of the following steps, which can be performed in the following order. There may be additional steps not described below. These additional steps may be before, between, or after those described.

As illustrated inFIGS.25,29, and33, the method can comprise applying an uncured thin film251on a substrate11. As illustrated inFIGS.26,30, and34, another step in the fifth method can include curing (i.e. causing a chemical reaction in) the uncured thin film251to form a cured thin film261. Characteristics of the uncured thin film251, characteristics of the cured thin film261, and curing are described below in the Added Features Applicable to All Methods section.

As illustrated inFIGS.27and33, the method can further comprise applying a reflective thin film272on the substrate11. As illustrated in FIGS.28a,28b,31,32, and35, the method can also include etching the reflective thin film, and also etching the cured thin film(s)261in some embodiments, to form polarization structures12.

As illustrated inFIG.25, the uncured thin film251can be a lower uncured thin film251Lapplied on the substrate11before applying the reflective thin film272. As illustrated inFIG.26, the lower uncured thin film251Lcan be cured to form a lower cured thin film261L. As illustrated inFIG.27, the reflective thin film272can be applied on the lower cured thin film261L. As illustrated inFIG.28a, the reflective thin film272can be etched to form polarization structures12, which can consist of reflective thin film polarization structures282.

As illustrated inFIG.28b, the lower cured thin film261Land the reflective thin film272can be etched to form polarization structures12including reflective thin film polarization structures282and lower cured thin film polarization structures281L. The lower cured thin film polarization structures281Lcan be sandwiched between the reflective thin film polarization structures282and the substrate11. Each lower cured thin film polarization structure281Lcan be aligned with a corresponding reflective thin film polarization structure282.

As illustrated inFIG.29, step290can follow step270, and an upper uncured thin film251Ucan be applied on the reflective thin film272. As illustrated inFIG.30, the upper uncured thin film251Ucan be cured to form an upper cured thin film261U. As illustrated inFIG.31, the upper cured thin film261Uand the reflective thin film272can be etched to form polarization structures12including upper cured thin film polarization structures281Uand reflective thin film polarization structures282. As illustrated inFIG.32, the upper cured thin film261U, the reflective thin film272, and the lower cured thin film261Lcan be etched to form polarization structures12including upper cured thin film polarization structures281U, reflective thin film polarization structures282, and lower cured thin film polarization structures281L. The reflective thin film polarization structures282can be sandwiched between the upper cured thin film polarization structures281Uand the lower cured thin film polarization structures281L. Each lower cured thin film polarization structure281L, reflective thin film polarization structure282, and upper cured thin film polarization structure281Ucan be aligned together.

As illustrated inFIG.33, the uncured thin film251can be an upper uncured thin film251Uand the reflective thin film272can be applied on the substrate11before applying the upper uncured thin film251U. As illustrated inFIG.34, the upper uncured thin film251Ucan be cured to form an upper cured thin film261U. As illustrated inFIG.35, the upper cured thin film261Uand the reflective thin film272can be etched to form polarization structures12including upper cured thin film polarization structures281Uand reflective thin film polarization structures282. The reflective thin film polarization structures282can be sandwiched between the upper cured thin film polarization structures281Uand the substrate11. Each upper cured thin film polarization structure281Ucan be aligned with a corresponding reflective thin film polarization structure282.

Added Features Applicable to all Methods

In the following discussion, the uncured cover layer34, the uncured fill layer134, the uncured imprintable layer184, the uncured backside layer234, the uncured thin film(s)251will be referred to as an uncured layer. In the following discussion, the cured cover layer44, the cured fill layer144, the cured printed layer204, the cured backside layer244, and the cured thin film(s)261will be referred to as a cured layer.

In one aspect, the uncured layer can be a liquid with solid inorganic nanoparticles dispersed throughout a continuous phase. Curing, or causing a chemical reaction in, the uncured layer can include forming the uncured layer into a solid, interconnecting network of the inorganic nanoparticles, defining a cured layer.

In another aspect, the uncured layer can be a colloidal suspension including a dispersed phase and a continuous phase. Curing, or causing a chemical reaction in, the colloidal suspension can include removing the continuous phase to form a solid, defining the cured layer. The solid can be inorganic.

The inorganic nanoparticles, the dispersed phase, or both can include some metal atoms bonded to organic moieties. In one aspect, each metal atom can be bonded to no more than one organic moiety. Examples of the organic moieties include —CH3and —CH2CH3. Consequently, the cured layer can include embedded organic moieties. These embedded organic moieties can be useful for changing properties of the cured layer, such as changing its optical properties and hardness.

In another embodiment, the uncured layer can be a solution including molecules in a solvent. The solvent can include water and an organic liquid. The molecules can include metal atoms bonded to reactive groups R1. Each reactive-group can be, independently, —Cl, —OR2, —OCOR2, or —N(R2)2, where R2is an alkyl group. The alkyl group has at least one carbon atom, but can be small, such as for example with ≤2 carbon atoms, ≤3 carbon atoms, ≤5 carbon atoms, or ≤10 carbon atoms. For example, the alkyl group can be —CH3or —CH2CH3. The solid inorganic nanoparticles referred to above can include the metal atoms described in this paragraph.

In certain embodiments, all bonds, or all except one of the bonds, of each of the metal atoms, can be to these reactive groups. For example, these molecules can be (CH3)Si(R1)3, Si(R1)4, Al(R1)3, (CH3)Al(R1)2, (CH3)Ti(R1)3, Ti(R1)4, or combinations thereof. Curing, or causing a chemical reaction in, the solution can include reacting the molecules to form a solid, defining the cured layer, with the metal atoms interconnected with each other. The solid can be inorganic. In one embodiment, the molecules can have a relatively small molecular weight, such as for example ≥70 g/mol, ≥80 g/mol, ≥90 g/mol, ≥100 g/mol, or ≥110 g/mol and ≤125 g/mol, ≤150 g/mol, ≤175 g/mol, or ≤200 g/mol.

Forming the uncured layer into the cured layer can include evaporation of at least some liquid. In one embodiment, all liquid initially in the uncured layer either reacts to form a solid (the cured layer) or is evaporated. Forming the uncured layer into the cured layer can include use of ultraviolet light, heat or both. Integrity of the cured layer can be improved by curing at a relatively low temperature, such as for example ≥30° C., ≥50° C., or ≥100° C. and ≤150° C., ≤200° C., ≤250° C., or ≤300° C.

The uncured layer, the cured layer, or both can have a low index of refraction for improved optical performance. This can be particularly beneficial for embodiments with cured layer in the channels13between the polarization structures12. For example, the index of refraction of uncured layer, the cured layer, or both can be ≤1.1, ≤1.2, ≤1.3, or ≤1.4. In one embodiment, the index of refraction of uncured layer, the cured layer, or both can be ≥1.0.

One way of achieving this low index of refraction is to include small voids or cavities in the cured layer. These small voids, filled with air, lower the overall index of refraction of the cured layer. For example, the cured layer can include silicon dioxide, with an index of refraction of around 1.4-1.5, but with the voids, the overall index of refraction can be <1.4. These voids can be formed by use of a solvent in the uncured layer which has larger molecules. For example, a solvent in the uncured layer can have a molecular weight of ≥70 g/mol, ≥80 g/mol, ≥90 g/mol, ≥100 g/mol, or ≥110 g/mol. As another example, a chemical in this solvent can have a large number of atoms, such as for example ≥15 atoms, ≥20 atoms, or ≥25 atoms. It can be a consideration for this solvent to not have too high of a molecular weight so that it can be sufficiently volatile. Therefore, this solvent can have a molecular weight of ≤125 g/mol, ≤150 g/mol, ≤175 g/mol, ≤200 g/mol, or ≤300 g/mol. This solvent can also have ≤30 atoms, ≤50 atoms, or ≤75 atoms. Further, this solvent can have a structure which occupies larger space, such as an aryl molecule or otherwise a molecule with double bonds. For example, the uncured layer can include benzene or xylene.

The inorganic nanoparticles, solid resulting from removing the continuous phase, and the metal atoms noted above can comprise aluminum, titanium, silicon, germanium, tin, lead, zirconium, or combinations thereof. The cured layer can include aluminum oxide, titanium oxide, silicon oxide, germanium oxide, tin oxide, lead oxide, zirconium oxide, or combinations thereof. Aluminum oxide can be particularly useful if a major function of the cured layer is heat transfer away from the polarization structures12. Silicon dioxide can be particularly useful due to its low index of refraction. Titanium dioxide can be particularly useful due to its high index of refraction.

The inorganic nanoparticles can be sized for keeping them out of the channels13. For example ≥90%, ≥95%, or ≥99% of the inorganic nanoparticles can have a diameter of ≥1 nm, ≥10 nm, or ≥50 nm. Alternatively, the inorganic nanoparticles can be sized for optimal filling the channels13. For example ≥90%, ≥95%, or ≥99% of the inorganic nanoparticles can have a diameter of ≤2 nm, ≤1 nm, or ≤0.5 nm.

As illustrated inFIGS.7-9,13-15,18-20, and22-24, and as described above, the method can include imprinting a pattern of structures. As illustrated inFIG.36, such imprinting can also include step360, imprinting separate pixels. AlthoughFIG.36shows different pixels with different wire direction with respect to each other, the pixels can differ in other ways with respect to each other.

As illustrated inFIGS.37-38, any of the methods above can further comprise sputter deposition of a thin film375onto the uncured layer, the cured layer, or both, represented by reference numbers374and384, respectively. The thin film375can be any material with desired optical properties, properties for protection of the polarizer, or both. The thin film265can be a dielectric. Sputter deposition of the thin film375can reduce voids in the uncured layer374, the cured layer384, or both; therefore this sputter deposition step is particularly useful for embodiments in which it is desirable for the uncured layer374and the cured layer384to fill the channels13.

The following can be used to improve applying the uncured layer, and forming the uncured layer into the cured layer, in any of the methods described above. The following steps can be performed in the following order: spin coating an uncured layer onto the polarization device or substrate11, defining a first spin coat; baking the polarizer or coated substrate11, defining a first bake; spin coating an uncured layer onto the first spin coat, defining a second spin coat; then baking the polarizer or coated substrate11, defining a second bake. The spin coating and baking steps can be repeated a third time, a fourth time, or more times. Uniformity of cured layer can be improved by multiple repeats of these spin coating and baking steps, but cost also increases with each repeat. Therefore, uniformity specifications can be weighed against cost in deciding the number of repeats, if any.

Time of each spin coat depends on desired thickness and on the spin coater. Example times include ≥2 seconds, ≥4 seconds, or ≥6 seconds and ≤10 seconds, ≤20 seconds, or ≤30 seconds for each spin coat.

Examples of speed of the first spin coat, the second spin coat, or additional spin coatings include ≥100 rpm, ≥500 rpm, ≥1000 rpm, or ≥1500 rpm and ≤2500 rpm, ≤3000 rpm, ≤4000 rpm, or ≤8000 rpm. Examples of temperature of the first bake, the second bake, or other bakes include ≥30° C., ≥50° C., ≥100° C., or ≥150° C. and ≤250° C., ≤300° C., or ≤400° C.

The uncured layer, the cured layer, or both can be relatively thick by the chemistry and methods of application described herein. For example, an average thickness Th of the layer, minimum thickness Thminof the layer, maximum thickness Thmaxof the layer can have the following values as specified in the claims: ≥10 nm, ≥50 nm, ≥100 nm, ≥200 nm and ≤300 nm, ≤600 nm, or ≤1000 nm.

The methods can be combined. For example, the overcoat layer14and the cured cover layer44can be applied on the polarizers shown inFIGS.10a-15or18-35and as described above. The cured fill layer144can be formed on top of the polarization structures12and extending into channels13between the polarization structures12shown inFIGS.18-21and25-35and as described above. The cured backside layer244can be formed on the second side11sof the substrate11of any of the polarizers described herein, as shown inFIGS.22-24and as described above. The cured thin film(s)251, the cured thin film polarization structures281, or both can be used with the any of the polarizers shown in the figures and described herein.