Light control film with random nanostructured etch stop

Abstract

A light control film includes a structured first major surface and a second major surface opposite thereto. The first major surface includes alternating first and second facets. Each of the first facets forms an average angle of less than 90 degrees with the second major surface. Each of the second facets forms an average angle greater than 60 degrees with the second major surface. Each of the first facets is etched to form a first nanostructured facet. Each of the first nanostructured facets includes nanopillars disposed across at least 70% of the first nanostructured facets. A coating layer coated on the first and second facets is conformal with the nanopillars of the first nanostructured facet and has an average thickness greater than 5 nm and less than 200 nm. The capping layer coated on the portion of the coating layer corresponding to the second facet has an average thickness greater than 0.05 [mu] m.

Description

SUMMARY OF THE INVENTION

[0001] In some aspects of the present specification, a light control film is provided. The light control film includes a structured first major surface and a second major surface opposite thereto. The structured first major surface includes a plurality of alternating first facets and second facets. Each first facet in the first facets forms an average first angle with the second major surface that is less than about 90 degrees, and each second facet in the second facets forms an average second angle with the second major surface that is greater than about 60 degrees. At least each of the plurality of first facets is etched to form a plurality of first nanostructured facets. Each first nanostructured facet in the first nanostructured facets includes a plurality of nanocolumns disposed across at least 70% of the first nanostructured facet. The nanocolumns in the plurality of nanocolumns have different heights and aspect ratios. A coating layer is coated substantially conformally on the first facets and the second facets so as to be at least substantially conformal with the nanocolumns of the first nanostructured facets. The coating layer has an average thickness greater than about 5 nm and less than about 200 nm. A covering layer is coated substantially conformally on a portion of the coating layer corresponding to the second facets and covers at least 70% of the portion of the coating layer. The covering layer has an average thickness greater than about 0.05 microns.

[0002] In some aspects of the present specification, a light control film is provided. The light control film includes a light transmissive body having a structured first major surface and an opposite second major surface. The structured first major surface includes a plurality of alternating first facets and second facets. Each first facet in the first facets forms an average first angle with the second major surface that is less than about 90 degrees, and each second facet in the second facets forms an average second angle with the second major surface that is greater than about 60 degrees. At least each of the plurality of first facets includes a plurality of nanocolumns disposed across at least 70% of the first facet, and at least some of the nanocolumns have an aspect ratio greater than 1.5. A coating layer is coated substantially conformally on the first facets and the second facets so as to be at least substantially conformal with the nanocolumns of the first facets. A covering layer is coated substantially conformally on a portion of the coating layer corresponding to the second facets and covers at least 70% of the portion of the coating layer. A planarizing outer coating conformally covers the structured first major surface and substantially planarizes the structured first major surface. The minimum average peel strength between the planarizing outer coating and the coating layer is greater than about 20 g / in. For at least one visible wavelength in the visible wavelength range extending from about 420 nm to about 680 nm, the magnitude of the difference between the refractive index of the light transmissive body and the planarizing outer coating is greater than about 0.05. For light incident on the light control film from a CIE standard light source D65, the light control film has an optical haze of less than about 30%.

[0003] In some aspects of the present specification, a light control film is provided. The light control film includes a light transmissive body having a structured first major surface that includes a plurality of alternating first facets and second facets. The angle formed between adjacent first and second facets is greater than about 5 degrees and less than about 150 degrees. A first coating layer is substantially conformally coated on the first and second facets and has an average thickness greater than about 5 nm and less than about 200 nm. A cover layer is substantially conformally coated on the coating layer portion corresponding to the second facet and covers at least 70% of the coating layer portion. A planarizing overcoat conformally covers the structured first major surface and substantially planarizes the structured first major surface. The light control film further includes a second coating layer disposed between the cover layer and the planarizing overcoat, the second coating layer having an average thickness less than about 200 nm. The first coating layer and the second coating layer comprise the same inorganic material.

[0004] In some aspects of the present specification, a light control film is provided. The light control film includes a light transmissive body having a structured first major surface that includes a plurality of alternating first facets and second facets. The angle formed between adjacent first facets is greater than about 5 degrees. At least some of the first facets are nanostructured and include a plurality of nanocolumns disposed across them. A coating layer is substantially conformally coated on at least some of the nanostructured first facets so as to be substantially conformal with at least the nanocolumns of the nanostructured first facets. The coating layer has an average thickness less than about 200 nm. A planarizing overcoat conformally covers the structured first major surface and substantially planarizes the structured first major surface; at a plurality of spaced-apart locations along at least the nanostructured first facet, elongated portions of the planarizing overcoat penetrate the nanostructured facet and into the light transmissive body.

[0005] In some aspects of the present specification, a method of fabricating a light control film is provided. The method of fabricating the light control film includes the following steps: (a) providing a light transmissive body having a structured first major surface and an opposing second major surface, the structured first major surface including a plurality of alternating first facets and second facets, each first facet in the first facets forming an average first angle with the second major surface that is less than about 90 degrees, and each second facet in the second facets forming an average second angle with the second major surface that is greater than about 60 degrees; (b) etching the structured first major surface such that each first facet in the first facets has a plurality of nanocolumns disposed across at least 70% of the first facet, at least some of the nanocolumns having an aspect ratio greater than 1.5; (c) depositing a first material to form a coating layer that coats the first facets and the second facets substantially conformally, so as to be substantially conformal with at least the nanocolumns of the first facets; (d) conformally depositing a light absorbing layer on the coating layer; and (e) selectively removing substantially at least 70% of the light absorbing layer from the first facets while substantially leaving at least 70% of the light absorbing layer on the second facets. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1A and Figure 1B A side view of a light control film according to an embodiment of the present specification is provided;

[0007] Figure 2 is a side view of a light control film according to an alternative embodiment of the present specification;

[0008] Figure 3 An alternative view of a light control film according to an embodiment of the present specification is provided;

[0009] Figure 4A and Figure 4B illustrates an embodiment of a display system featuring a light control film according to an embodiment of the present specification;

[0010] Figure 5 includes a close-up image of a light control film layer shown in detail according to an embodiment of the present specification;

[0011] Figure 6 includes an image of a light control film showing nanocolumn features according to an embodiment of the present specification;

[0012] Figure 7 is an image of a light control film according to an embodiment of the present specification, showing an elongated portion of a planarized outer coating penetrating a nanostructured facet;

[0013] Figure 8 is another image of a light control film according to an embodiment of the present specification, showing an elongated portion penetrating a nanostructured facet;

[0014] Figure 9 Details of a method for preparing a light-controlled film according to an embodiment of the present specification are shown; and

[0015] Figure 10 A view of a light-controlled film and a substrate for peel strength testing according to an embodiment of the present specification is provided. DETAILED DESCRIPTION

[0016] Reference is made in the following description to the accompanying drawings, which form a part of the present disclosure and in which various embodiments are shown by way of illustration. The drawings are not necessarily to scale. It is to be understood that other embodiments may be conceived and effected without departing from the scope or spirit of the present specification. Accordingly, the following detailed description should not be taken in a limiting sense.

[0017] Etch stop layers are commonly used in the semiconductor industry to precisely control the depth of a reactive ion etching (RIE) process. These layers are typically smooth, continuous layers deposited by various vacuum processes, including physical vapor deposition (PVD), plasma-enhanced chemical vapor deposition (PECVD), and atomic layer deposition (ALD). The chemistry of the etch stop is selected to obtain a high etch selectivity in the layer being etched. The most common choice is an inorganic thin layer.

[0018] The smooth inorganic surface serves as an etch stop layer, allowing the RIE process to selectively remove the material layer without etching into the underlying surface, which could add additional unwanted haze. However, in applications where backfill resin is required, these smooth inorganic etch stop layers do not promote good adhesion.

[0019] Etch stop layers can also be used in optical films that require patterning. In these cases, the thickness and optical constants of the etch stop layer also need to be considered. It is important to maintain a thin layer when using an etch stop layer with any significant difference in extinction coefficient or refractive index from the adjacent layer. For these purposes, SiO2, TiO2, and AlO2 all provide excellent choices. In these applications, the etch stop surface maintains a minimum roughness to provide a minimum thickness requirement and has little additional haze. However, it is difficult to bond the smooth inorganic layer during the casting and curing processes.

[0020] A method of producing a light control film described herein combines small random nanostructures with a continuous inorganic layer to significantly improve adhesion to an overlying resin and significantly add haze. The method and resulting articles perform well on substrates (such as Fresnel lenses) with varying angles and aspect ratios. However, these varying angles and aspect ratios receive different free radical and ion fluxes during plasma treatment, which can make it difficult to achieve nanostructures smaller than typical haze formation sizes while still maintaining good etch stop performance on all facets.

[0021] According to some aspects of the present specification, a light control film having a nanostructured etch stop surface can provide robust etch stop performance, low haze, and improved adhesion to an overlying resin. In some embodiments, the light control film can have a structured first major surface and a second major surface opposite thereto. In some embodiments, the structured first major surface can include a plurality of alternating first facets and second facets (e.g., alternating facets of a Fresnel lens). In some embodiments, each first facet of the first facets can form an average first angle q1 with the second major surface that is less than about 90 degrees, or less than about 85 degrees, or less than about 80 degrees, or less than about 75 degrees, or less than about 70 degrees, or less than about 65 degrees, or less than about 60 degrees, or less than about 55 degrees, or less than about 50 degrees, or less than about 45 degrees, or less than about 40 degrees, or less than about 35 degrees, or less than about 30 degrees, or less than about 25 degrees, or less than about 20 degrees, or less than about 15 degrees, or less than about 10 degrees, or less than about 5 degrees, or less than 3 degrees, or less than 1 degree. In some embodiments, each second facet of the second facets can form an average second angle θ2 with the second major surface that is greater than about 60 degrees, or greater than about 65 degrees, or greater than about 70 degrees, or greater than about 75 degrees, or greater than about 80 degrees, or greater than about 85 degrees, or greater than about 90 degrees, or greater than about 95 degrees, or greater than about 96 degrees, or greater than about 97 degrees, or greater than about 98 degrees, or greater than about 99 degrees.

[0022] In some embodiments, at least each of the plurality of first facets can be etched to form a plurality of first nanostructured facets. In some embodiments, each first nanostructured facet of the first nanostructured facets can include a plurality of features (e.g., nanocolumns) disposed across at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95% of the first nanostructured facet. In some embodiments, each of the features can have a different height and aspect ratio (e.g., ratio of height to width). In some embodiments, at least one of the first facets can not be etched and can not include any nanocolumns.

[0023] In some embodiments, a coating layer (e.g., an etch stop layer) may be coated substantially conformally on the first facet and the second facet to be substantially conformal with at least the nanocolumns of the first nanostructured facet. In some embodiments, the coating layer may have an average thickness greater than about 5 nm, or greater than about 7.5 nm, or greater than about 10 nm, or greater than about 12.5 nm, or greater than about 15 nm, or greater than about 17.5 nm, or greater than about 20 nm, and less than about 200 nm, or less than about 180 nm, or less than about 160 nm, or less than about 150 nm, or less than about 140 nm, or less than about 120 nm, or less than about 100 nm, or less than about 90 nm, or less than about 80 nm, or less than about 70 nm, or less than about 60 nm, or less than about 50 nm, or less than about 40 nm, or less than about 30 nm, or less than about 20 nm.

[0024] In some embodiments, a capping layer (e.g., a light absorbing layer) may be coated substantially conformally on the portion of the coating layer corresponding to the second facet and cover at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95% of the coating layer portion. In some embodiments, the capping layer may have an average thickness greater than about 0.05 microns, or greater than about 0.1 microns, or greater than about 0.15 microns, or greater than about 0.2 microns, or greater than about 0.25 microns, or greater than about 0.3 microns, or greater than about 0.35 microns, or greater than about 0.4 microns, or greater than about 0.45 microns, or greater than about 0.5 microns, or greater than about 0.55 microns, or greater than about 0.6 microns, or greater than about 0.65 microns, or greater than about 0.7 microns, or greater than about 0.75 microns, or greater than about 1.0 microns, or greater than about 1.25 microns, or greater than about 1.5 microns, or greater than about 2 microns, or greater than about 2.5 microns, or greater than about 3 microns.

[0025] In some embodiments, the capping layer may be deposited by layer-by-layer (LbL) deposition (sometimes referred to as LbL coating, LbL assembly, or LbL self-assembly). This coating method is based on the sequential self-limiting adsorption of materials with complementary groups and can thus provide a substantially conformal coating on a structured surface. The most common complementary functional groups are positively charged (e.g., amine) and negatively charged (e.g., carboxylic acid, sulfonic acid, phosphonic acid) groups. Typical materials include polyelectrolyte polymers and / or nanoparticles, such as surface-modified pigments (e.g., carbon black) or metal oxides. More details regarding LbL coating of microstructured surfaces and then selective removal of the coating via reactive ion etching (RIE) are provided in WO2019118685 (Schmidt et al.), which is incorporated herein by reference.

[0026] In some embodiments, at least 50%, or at least 60%, or at least 70%, or at least 80%, or at least 90% of the first facets of the structured first major surface may be curved. In some embodiments, at least 50%, or at least 60%, or at least 70%, or at least 80%, or at least 90% of the first facets may be substantially planar.

[0027] In some embodiments, the nanocolumns may have a height in the range of from about 1 nm to about 1000 nm (e.g., between about 20 nm and about 500 nm). In some embodiments, the nanocolumns may have a width in the range of from about 1 nm to about 1000 nm (e.g., between about 5 nm and about 100 nm). In some embodiments, the shape of the nanocolumns may be undercut, trapezoidal, inverted trapezoidal, or pyramidal or any other suitable shape. In some embodiments, at least one of the nanocolumns of at least one of the first nanostructured facets may have an aspect ratio greater than about 1.5, or greater than about 2, or greater than about 3, or greater than about 4, or greater than about 5, or greater than about 10, or greater than about 15.

[0028] In some embodiments, the overcoat layer may cover at most 40%, or at most 35%, or at most 30%, or at most 25%, or at most 20%, or at most 15%, or at most 10%, or at most 5% of the coating layer corresponding to the first nanostructured facet (e.g., the overcoat layer may be substantially removed from the first nanostructured facet). In some embodiments, the overcoat layer may be substantially light-absorbing. In some such embodiments, the light-absorbing overcoat layer may include a plurality of light-absorbing particles. In some such embodiments, the light-absorbing particles may include one or more of dyes, pigments, polyelectrolytes, and carbon black. In some such embodiments, the light-absorbing overcoat layer may have an optical density greater than about 0.1, or greater than about 0.2, or greater than about 0.4, or greater than about 0.6, or greater than about 0.8, or greater than about 1, or greater than about 1.1, or greater than about 1.2, or greater than about 1.3, or greater than about 1.5, or greater than about 2, or greater than about 2.5, or greater than about 3, or greater than about 3.5, or greater than about 4, or greater than about 4.5, or greater than about 5, or greater than about 5.5, or greater than about 6.

[0029] In some embodiments, the light control film may further include a light transmissive body that includes a structured first major surface and an opposing second major surface. In some embodiments, the first and second facets may be substantially linear facets that extend along the length direction (e.g., the y-axis) of the light control film and are arranged along the orthogonal width direction (e.g., the x-axis) of the light control film.

[0030] In some embodiments, at least some of the first facets in the first facet are curved. In some such embodiments, the structured first major surface may have a positive focal length for at least one visible wavelength in the visible (i.e., human visible) wavelength range extending from about 420 nm to about 680 nm.

[0031] In some embodiments, the light control film may further include a planarizing overcoat that conformally covers the structured first major surface and substantially planarizes the structured first major surface. In some such embodiments, the minimum average peel strength between the planarizing overcoat and the coating layer may be greater than about 20 grams per inch, or greater than about 50 grams per inch, or greater than about 100 grams per inch, or greater than about 250 grams per inch, or greater than about 500 grams per inch, or greater than about 750 grams per inch, or greater than about 1000 grams per inch. In some such embodiments, for light incident on the light control film from a CIE standard light source D65, the light control film may have an optical haze of less than about 30%, or less than about 25%, or less than about 20%, or less than about 15%, or less than about 10%, or less than about 5%, or less than about 2.5%, or less than about 1%, or less than about 0.5%. In some such embodiments, the light control film may further include a light transmissive body that includes the structured first major surface and an opposing second major surface, and wherein for at least one visible wavelength in the visible wavelength range extending from about 420 nm to about 680 nm, the magnitude of the difference between the refractive index of the light transmissive body and the planarizing overcoat may be greater than about 0.05, or greater than about 0.06, or greater than about 0.07, or greater than about 0.08, or greater than about 0.09, or greater than about 0.1, and less than about 0.5, or less than about 0.45, or less than about 0.4, or less than about 0.35, or less than about 0.3, or less than about 0.25.

[0032] In some embodiments, a display system may include any one of the light control films of the present specification disposed on a display (e.g., an LCD or LED display) configured to form an image, and a second light control film disposed between the light control film and the display. In some such embodiments, the second light control film may include a plurality of alternating substantially light transmissive regions and substantially light absorbing regions. In some such embodiments, a first adhesive layer (e.g., an adhesive) may bond the light control film to the second light control film, and a second adhesive layer may bond the second light control film to the display. Alternatively, the adhesive layer may be applied to the first light control film and bonded to the front surface, such as a cover lens on the display.

[0033] In accordance with some aspects of the present specification, the light control film may include a light transmissive body having a structured first major surface and an opposing second major surface. In some embodiments, the structured first major surface may include a plurality of alternating first facets and second facets (e.g., the facets of a Fresnel lens surface).

[0034] In some embodiments, each first facet of the first facets may form an average first angle θ1 with the second major surface that is less than about 90 degrees, or less than about 85 degrees, or less than about 80 degrees, or less than about 75 degrees, or less than about 70 degrees, or less than about 65 degrees, or less than about 60 degrees, or less than about 55 degrees, or less than about 50 degrees, or less than about 45 degrees, or less than about 40 degrees, or less than about 35 degrees, or less than about 30 degrees, or less than about 25 degrees, or less than about 20 degrees, or less than about 15 degrees, or less than about 10 degrees, or less than about 5 degrees, or less than about 3 degrees, or less than about 1 degree. In some embodiments, each second facet of the second facets may form an average second angle θ2 with the second major surface that is greater than about 60 degrees, or greater than about 65 degrees, or greater than about 70 degrees, or greater than about 75 degrees, or greater than about 80 degrees, or greater than about 85 degrees, or greater than about 90 degrees, or greater than about 95 degrees, or greater than about 96 degrees, or greater than about 97 degrees, or greater than about 98 degrees, or greater than about 99 degrees.

[0035] In some embodiments, at least each first facet of the plurality of first facets may include a plurality of nanocolumns (e.g., nanostructures or features) disposed across at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95% of the first facet. In some embodiments, at least some of the nanocolumns may have an aspect ratio greater than 1.5, or greater than 2, or greater than 3, or greater than 4, or greater than 5, or greater than 10, or greater than 15.

[0036] In some embodiments, at least two of the plurality of first facets including the nanocolumns have different nanocolumn densities. In some embodiments, at least two of the plurality of first facets including the nanocolumns have different average aspect ratios of the nanocolumns.

[0037] In some embodiments, a coating layer (e.g., an etch stop layer) may be coated substantially conformally on the first and second facets so as to be substantially conformal with at least the nanocolumns of the first facet. In some embodiments, a cover layer (e.g., a light absorption layer) may be coated substantially conformally on a portion of the coating layer corresponding to the second facet and cover at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95% of the portion of the coating layer.

[0038] In some embodiments, the planarizing overcoat may conformally cover the structured first major surface and substantially planarize the structured first major surface. In some such embodiments, the minimum average peel strength between the planarizing overcoat and the coating layer is greater than about 20 grams per inch, or greater than about 50 grams per inch, or greater than about 100 grams per inch, or greater than about 250 grams per inch, or greater than about 500 grams per inch, or greater than about 750 grams per inch, or greater than about 1000 grams per inch.

[0039] In some embodiments, for at least one visible wavelength within the visible wavelength range extending from about 420 nm to about 680 nm, the magnitude of the difference between the refractive index of the light-transmissive body and the planarizing overcoat is greater than about 0.05, or greater than about 0.06, or greater than about 0.07, or greater than about 0.08, or greater than about 0.09, or greater than about 0.1. In some embodiments, for light incident on the light control film from a CIE standard light source D65, the light control film has an optical haze of less than about 30%, or less than about 25%, or less than about 20%, or less than about 15%, or less than about 10%, or less than about 5%, or less than about 2.5%, or less than about 1%, or less than about 0.5%.

[0040] According to some aspects of the present specification, the light control film may include a light-transmissive body having a structured first major surface that includes a plurality of alternating first facets and second facets. In some embodiments, the included angle θ3 formed between adjacent first facets and second facets may be greater than about 5 degrees, or greater than about 10 degrees, or greater than about 15 degrees, or greater than about 20 degrees, or greater than about 25 degrees, or greater than about 30 degrees, and less than about 150 degrees, or less than about 140 degrees, or less than about 130 degrees, or less than about 120 degrees, or less than about 100 degrees.

[0041] In some embodiments, the light control film may further include a first coating layer (e.g., an etch stop layer) that is substantially conformally coated on the first facets and the second facets and has an average thickness greater than about 5 nm, or greater than about 7.5 nm, or greater than about 10 nm, or greater than about 12.5 nm, or greater than about 15 nm, or greater than about 17.5 nm, or greater than about 20 nm, and less than about 200 nm, or less than about 180 nm, or less than about 160 nm, or less than about 150 nm, or less than about 140 nm, or less than about 120 nm, or less than about 100 nm, or less than about 90 nm, or less than about 80 nm, or less than about 70 nm, or less than about 60 nm, or less than about 50 nm, or less than about 40 nm, or less than about 30 nm, or less than about 20 nm.

[0042] In some embodiments, the light control film may further include a cover layer (e.g., a light absorption layer) that is substantially conformally coated on the coated layer portion corresponding to the second facet and covers at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95% of the coated layer portion. In some embodiments, the cover layer may be substantially removed from the first facet.

[0043] In some embodiments, the light control film may further include a planarizing overcoat that conformally covers the structured first major surface and substantially planarizes the structured first major surface.

[0044] In some embodiments, the light control film may further include a second coated layer disposed between the cover layer and the planarizing overcoat and having an average thickness of less than about 200 nm, or less than about 180 nm, or less than about 160 nm, or less than about 150 nm, or less than about 140 nm, or less than about 120 nm, or less than about 100 nm, or less than about 90 nm, or less than about 80 nm, or less than about 70 nm, or less than about 60 nm, or less than about 50 nm, or less than about 40 nm, or less than about 30 nm, or less than about 20 nm. In some embodiments, the first coated layer and the second coated layer may comprise the same inorganic material (e.g., silicon).

[0045] According to some aspects of the present specification, the light control film may include a light transmissive body having a structured first major surface that includes a plurality of alternating first facets and second facets. In some embodiments, the included angle θ3 formed between adjacent first facets and second facets may be greater than about 5 degrees, or greater than about 10 degrees, or greater than about 15 degrees, or greater than about 20 degrees, or greater than about 25 degrees, or greater than about 30 degrees and less than about 150 degrees, or less than about 140 degrees, or less than about 130 degrees, or less than about 120 degrees, or less than about 100 degrees. In some embodiments, at least some of the first facets may be nanostructured and may include a plurality of nanocolumns disposed across thereof.

[0046] In some embodiments, the light control film may further include a coating layer (e.g., an etch stop layer) that is substantially conformally coated on at least some of the nanostructured first facets such that it is substantially conformal with at least the nanocolumns of the nanostructured first facets. In some such embodiments, the coating layer may have an average thickness of less than about 200 nm, or less than about 180 nm, or less than about 160 nm, or less than about 150 nm, or less than about 140 nm, or less than about 120 nm, or less than about 100 nm, or less than about 90 nm, or less than about 80 nm, or less than about 70 nm, or less than about 60 nm, or less than about 50 nm, or less than about 40 nm, or less than about 30 nm, or less than about 20 nm.

[0047] In some embodiments, the light control film may further include a planarizing overcoat that conformally covers the structured first major surface and substantially planarizes the structured first major surface. In some such embodiments, at a plurality of spaced positions along at least the nanostructured first facets, the elongate portions of the planarizing overcoat may penetrate the nanostructured facets and enter the light transmissive body. In some embodiments, at least some of the elongate portions may have a length greater than about 50 nm, or greater than about 100 nm, or greater than about 200 nm, or greater than about 500 nm, or greater than about 750 nm, or greater than about 1 micron, or greater than about 2 microns, or greater than about 3 microns, or greater than about 4 microns, or greater than about 5 microns, or greater than about 10 microns. In some embodiments, at least some of the elongate portions may extend in a direction at an angle θ4 greater than about 5 degrees, or greater than about 10 degrees, or greater than about 15 degrees with respect to the normal of the corresponding nanostructured first facet. In some embodiments, the elongate portions may correspond to the same nanostructured first facet and may be substantially parallel to each other.

[0048] According to some aspects of the present specification, a method for preparing a light control film includes the following steps: (a) providing a light transmissive body including a structured first major surface and an opposite second major surface, the structured first major surface including a plurality of alternating first facets and second facets, each first facet of the first facets forming an average first angle θ1 with the second major surface that is less than about 90 degrees, or less than about 85 degrees, or less than about 80 degrees, or less than about 75 degrees, or less than about 70 degrees, or less than about 65 degrees, or less than about 60 degrees, or less than about 55 degrees, or less than about 50 degrees, or less than about 45 degrees, or less than about 40 degrees, or less than about 35 degrees, or less than about 30 degrees, or less than about 25 degrees, or less than about 20 degrees, or less than about 15 degrees, or less than about 10 degrees, or less than about 5 degrees, or less than about 3 degrees, or less than about 1 degree, and each second facet of the second facets forming an average second angle θ2 with the second major surface that is greater than about 60 degrees, or greater than about 65 degrees, or greater than about 70 degrees, or greater than about 75 degrees, or greater than about 80 degrees, or greater than about 85 degrees, or greater than about 90 degrees, or greater than about 95 degrees, or greater than about 96 degrees, or greater than about 97 degrees, or greater than about 98 degrees, or greater than about 99 degrees; (b) etching the structured first major surface such that each first facet of the first facets has a plurality of nanocolumns disposed across at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95% of the first facet, and at least some of the nanocolumns having an aspect ratio greater than about 1.5, or greater than about 2, or greater than about 3, or greater than about 4, or greater than about 5, or greater than about 10, or greater than about 15; (c) depositing a first material to form a coating layer (e.g., an etch stop layer), the coating layer being substantially conformally coated on the first and second facets such that it is substantially conformal with at least the nanocolumns of the first facet; (d) conformally depositing a light absorption layer on the coating layer; and (e) selectively removing substantially at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95% of the light absorption layer from the first facet while leaving substantially at least 70% of the light absorption layer on the second facet.

[0049] In some embodiments, the method for preparing a light control film further includes depositing a mask layer on the structured first major surface before etching the structured first major surface. That is, in some embodiments, the mask layer is deposited first before the etching step to facilitate the etching step. In some other embodiments, depositing the mask layer on the structured first major surface is performed substantially simultaneously with etching the structured first major surface.

[0050] In some embodiments, the method of preparing the light control film may further include (f) conformally depositing a planarizing overcoat that substantially planarizes the structured first major surface. In some such embodiments, the minimum average peel strength between the planarizing overcoat and the coating layer may be greater than about 20 grams per inch, or greater than about 50 grams per inch, or greater than about 100 grams per inch, or greater than about 250 grams per inch, or greater than about 500 grams per inch, or greater than about 750 grams per inch, or greater than about 1000 grams per inch.

[0051] In some embodiments, for light incident on the light control film from a CIE standard light source D65, the light control film may have an optical haze of less than about 30%, or less than about 25%, or less than about 20%, or less than about 15%, or less than about 10%, or less than about 5%, or less than about 2.5%, or less than about 1%, or less than about 0.5%.

[0052] Turning now to the drawings, Figure 1A and Figure 1B there is provided a cross-sectional side view of an embodiment of a light control film in accordance with the present specification. Figure 1B There is provided Figure 1A a close-up view of a portion of the light control film in

[0053] In some embodiments, each of the first facets 20 in the first faceted surface may form an average first angle θ1 with the second major surface that is less than about 90 degrees, or less than about 85 degrees, or less than about 80 degrees, or less than about 75 degrees, or less than about 70 degrees, or less than about 65 degrees, or less than about 60 degrees, or less than about 55 degrees, or less than about 50 degrees, or less than about 45 degrees, or less than about 40 degrees, or less than about 35 degrees, or less than about 30 degrees, or less than about 25 degrees, or less than about 20 degrees, or less than about 15 degrees, or less than about 10 degrees, or less than about 5 degrees, or less than about 3 degrees, or less than about 1 degree. In some embodiments, each of the second facets in the second faceted surface may form an average second angle θ2 with the second major surface that is greater than about 60 degrees, or greater than about 65 degrees, or greater than about 70 degrees, or greater than about 75 degrees, or greater than about 80 degrees, or greater than about 85 degrees, or greater than about 90 degrees, or greater than about 95 degrees, or greater than about 96 degrees, or greater than about 97 degrees, or greater than about 98 degrees, or greater than about 99 degrees. In some embodiments, the adjacent first facet 20 and second facet 30 may form an included angle θ3 therebetween that is greater than about 5 degrees, or greater than about 10 degrees, or greater than about 15 degrees, or greater than about 20 degrees, or greater than about 25 degrees, or greater than about 30 degrees and less than about 150 degrees, or less than about 140 degrees, or less than about 130 degrees, or less than about 120 degrees, or less than about 100 degrees.

[0054] In some embodiments, at least each of the plurality of first facets 20 may be etched to form a plurality of first nanostructured facets 20. In some embodiments, each of the first nanostructured facets 20 in the first nanostructured faceted surface may include a plurality of nanocolumns 40 disposed across at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95% of the first nanostructured facet 20. In some embodiments, the nanocolumns 40 may have different heights h1, different widths w1, and different aspect ratios h1 / w1 (see Figure 1B ).

[0055] In some embodiments, the coating layer 50 (e.g., an etch stop layer) may be coated substantially conformally on the first facet / first nanostructured facet 20 and the second facet 30 so as to be substantially conformal with at least the nanocolumns 40 of the first nanostructured facet 20. In some embodiments, the coating layer may have an average thickness h2 that is greater than about 5 nm, or greater than about 7.5 nm, or greater than about 10 nm, or greater than about 12.5 nm, or greater than about 15 nm, or greater than about 17.5 nm, or greater than about 20 nm, and less than about 200 nm, or less than about 180 nm, or less than about 160 nm, or less than about 150 nm, or less than about 140 nm, or less than about 120 nm, or less than about 100 nm, or less than about 90 nm, or less than about 80 nm, or less than about 70 nm, or less than about 60 nm, or less than about 50 nm, or less than about 40 nm, or less than about 30 nm, or less than about 20 nm.

[0056] In some embodiments, the cover layer 60 (e.g., a light absorption layer) may be coated substantially conformally on the coating layer portion corresponding to the second facet 30 and cover at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95% of the coating layer portion. In some embodiments, the cover layer 60 may have an average thickness h3 that is greater than about 0.05 microns, or greater than about 0.1 microns, or greater than about 0.15 microns, or greater than about 0.2 microns, or greater than about 0.25 microns, or greater than about 0.3 microns, or greater than about 0.35 microns, or greater than about 0.4 microns, or greater than about 0.45 microns, or greater than about 0.5 microns, or greater than about 0.55 microns, or greater than about 0.6 microns, or greater than about 0.65 microns, or greater than about 0.7 microns, or greater than about 0.75 microns, or greater than about 1.0 microns, or greater than about 1.25 microns, or greater than about 1.5 microns, or greater than about 2 microns, or greater than about 2.5 microns, or greater than about 3 microns.

[0057] In some embodiments, at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 95% of the second facet 30 is substantially planar. In some embodiments, at least 50%, or at least 60%, or at least 70%, or at least 80%, or at least 90% of the first facet 20 may be curved. In some embodiments, at least 50%, or at least 60%, or at least 70%, or at least 80%, or at least 90% of the first facet 11 (e.g., see the first facet 11a of Figure 2 may be substantially planar. In some embodiments, at least some of the first facets in the first facet 20 may be curved such that the structured first main surface 11 has a positive focal length for at least one visible wavelength within the visible wavelength range extending from about 420 nm to about 680 nm.

[0058] In some embodiments, the nanocolumns 40 may have a height h1 in the range of about 1 nm to about 1000 nm. In some embodiments, the nanocolumns 40 may have a height h1 in a typical range greater than about 20 nm and less than 500 nm. In some embodiments, the nanocolumns 40 may have a width w1 in the range of about 1 nm to about 1000 nm (typically about 5 nm to less than 100 nm). In some embodiments, the nanocolumns 40 may have undercuts. In some embodiments, the shape of the nanocolumns 40 may be a rectangular prism, trapezoid, inverted trapezoid, or pyramid. In some embodiments, at least one nanocolumn 40 of at least one first nanostructured facet 20 in the first nanostructured facet 20 may have an aspect ratio greater than about 1.5, or greater than about 2, or greater than about 3, or greater than about 4, or greater than about 5, or greater than about 10, or greater than about 15. In some embodiments, at least two of the first facets 20 including the nanocolumns 40 have different nanocolumn densities. In some embodiments, at least two of the first facets 20 including the nanocolumns 40 have different average aspect ratios of the nanocolumns.

[0059] In some embodiments, the overcoat layer 60 may cover at most 40%, or at most 35%, or at most 30%, or at most 25%, or at most 20%, or at most 15%, or at most 10%, or at most 5% of the coating layer 50 corresponding to the first nanostructured facet 20. In some embodiments, the overcoat layer 60 may be light-absorbing. In some such embodiments, the light-absorbing overcoat layer 60 may include a plurality of light-absorbing particles. In some such embodiments, the light-absorbing particles may include one or more of dyes, pigments, polyelectrolytes, and carbon black. In some embodiments, the light-absorbing overcoat layer may have an optical density greater than about 0.1, or greater than about 0.2, or greater than about 0.4, or greater than about 0.6, or greater than about 0.8, or greater than about 1, or greater than about 1.1, or greater than about 1.2, or greater than about 1.3, or greater than about 1.5, or greater than about 2, or greater than about 2.5, or greater than about 3, or greater than about 3.5, or greater than about 4, or greater than about 4.5, or greater than about 5, or greater than about 5.5, or greater than about 6.

[0060] In some embodiments, for at least one visible wavelength within the visible wavelength range extending from about 420 nm to about 680 nm, the magnitude of the difference between the refractive index of the light transmissive body 10 and the planarized outer coating 80 can be greater than about 0.05, or greater than about 0.06, or greater than about 0.07, or greater than about 0.08, or greater than about 0.09, or greater than about 0.1, and less than about 0.5, or less than about 0.45, or less than about 0.4, or less than about 0.35, or less than about 0.3, or less than about 0.25. In some embodiments, for light incident on the light control film from a CIE standard light source D65, the light control film 300 can have an optical haze of less than about 30%, or less than about 25%, or less than about 20%, or less than about 15%, or less than about 10%, or less than about 5%, or less than about 2.5%, or less than about 1%, or less than about 0.5%.

[0061] In some embodiments, the minimum average peel strength between the planarized outer coating 80 and the coating layer 50 (when peeling in the y - direction as shown Figure 1A can be greater than about 20 grams per inch, or greater than about 50 grams per inch, or greater than about 100 grams per inch, or greater than about 250 grams per inch, or greater than about 500 grams per inch, or greater than about 750 grams per inch, or greater than about 1000 grams per inch.

[0062] Figure 2 is Figure 1A a side view of an alternative embodiment of the light control film 300. Figure 2 is shared with Figure 1A an embodiment of the light control film 300 and shares several elements with the same reference numerals, and unless otherwise specified herein, these elements with the same reference numerals are assumed to have the same functions as their corresponding elements in Figure 1A . Figure 2 It is intended to illustrate that in some embodiments, some portions (i.e., at least 50%) of the first facet 20 can be substantially planar (see facet 11a). In some embodiments, at least one of the first facets in the first facet 11a may not be etched and thus does not include any nanocolumns.

[0063] Figure 3 provides Figure 1A an alternative view of an embodiment of the light control film 300. Compared with the side view of the light control film 300 shown in the lower portion of Figure 3 , the upper portion of Figure 3 shows a top plan view of the same film. Figure 3 is shared with Figure 1A an embodiment of the light control film 300 and shares several elements with the same reference numerals, and unless otherwise specified herein, these elements with the same reference numerals are assumed to have the same functions as their corresponding elements in Figure 1AThe same functions as their corresponding components therein. In some embodiments, the first facet 20 and the second facet 30 may be along the length direction of the light control film 300 (e.g., Figure 3 the y-axis as shown in the upper part of Figure 3 and arranged along the orthogonal width direction of the light control film 300 (e.g.,

[0064] Figure 4A and Figure 4B illustrate embodiments of a display system characterized by embodiments of the light control film according to the present specification. Starting from Figure 4A in some embodiments, the display system 400 may include any one of the embodiments of the light control film 300 described herein disposed on a display 70 configured to form an image 71, and a second light control film 200 (e.g., a louver film) disposed between the light control film 300 and the display 70. In some embodiments, the second light control film 200 may include a plurality of alternating substantially light-transmissive regions 201 and substantially light-absorbing regions 202. In some embodiments, a first adhesive layer 94 bonds the light control film 300 to the second light control film 200, and a second adhesive layer 96 bonds the second light control film 200 to the display 70. In some embodiments, the second adhesive layer 96 may bond the second light control film 200 to a portion of the display 70, such as a cover lens 98. In some such embodiments, an air gap 99 may exist between the cover lens 98 and the display 70.

[0065] In Figure 4A the illustrated embodiment, the light control film 300 is disposed on the side of the cover lens 98 facing away from the display 70. In Figure 4B an alternative embodiment of the display system 400a shown, the light control film 300 may be disposed under the cover lens 98 on the side of the cover lens 98 facing the display 70. In this embodiment, an air gap 99 may be disposed between the display 70 and the second light control film 200. In this embodiment, an adhesive layer 96 (e.g., an optically clear adhesive) may bond the light control film 300 to the cover lens 98. The planarization layer 80 of the light control film 300 may include a substrate 95.

[0066] When the planarization layer 80 is as Figure 4BWhen disposed between the structured first major surface 11 of the light control film 300 and the substrate 95, the film assembly 450 can be used, and a 90-degree peel test (such as the test described in ASTM D6862-11(2021), but with some modifications) can be used to test the adhesion between the structured first major surface 11 and the planarization layer 80. A strip of the film assembly 450 with dimensions of 25 mm x 800 mm can be cut in a direction parallel to the linear prism direction. The substrate 95 can be attached to a rigid plate using 3M 410 double-sided tape, where the adhesive side of the tape is applied to the rigid plate. The liner of the 410 tape can be removed, and the substrate surface 95 can be adhered to the 410 tape. The louver side of the film is scribed to initiate peeling at the interface between the structured first major surface 11 and the planarization layer 80. An inch section of the louver side is placed into the test machine jaws or fixture. The test is conducted using a 10-pound load cell and a constant crosshead speed of 10 inches per minute.

[0067] It should be noted that Figure 4A and Figure 4B are schematic diagrams showing the order and placement of layers to illustrate possible embodiments of the display system, and are not intended to be accurate with respect to layer thicknesses and component dimensions. Additionally, the display system can include Figure 4A and Figure 4B other layers not shown in

[0068] Figure 5 A close-up image showing in detail the layers of an embodiment of the light control film according to the present specification. Figure 5 (a) to Figure 5 (d) show various close-up images of physical samples of the light control film 300 of Figure 1A and other figures herein. It should be noted that the orientation of the images is the same as the illustration in Figures 1A to 1B (see the XYZ coordinate system reference in Figure 5 ), but the images are focused on one of the second facets 30, which in this example is substantially vertical. As shown in Figure 5 (a), starting from the left side of the image, the elements of the light control film are the light transmissive body 10, the first coating layer 50 (e.g., an etch stop layer), the cover layer 60, and the planarization overcoat 80. In some embodiments, as shown in Figure 5 (b), 5(c) and Figure 5 (d), the light control film can also include a second coating layer 90 disposed between the cover layer 60 and the planarization overcoat 80. (It should be noted that Figure 5 (b), Figure 5 (c) and Figure 5(d) The image has been enhanced with a graphic that better shows the second coating layer 90, which is not well shown in the black and white images used herein. In some embodiments, the second coating layer 90 may have an average thickness of less than about 200 nm, or less than about 180 nm, or less than about 160 nm, or less than about 150 nm, or less than about 140 nm, or less than about 120 nm, or less than about 100 nm, or less than about 90 nm, or less than about 80 nm, or less than about 70 nm, or less than about 60 nm, or less than about 50 nm, or less than about 40 nm, or less than about 30 nm, or less than about 20 nm. In some embodiments, the first coating layer 50 and the second coating layer 90 may comprise the same inorganic material (e.g., silicon). In some embodiments, the second coating layer 90 may only cover a portion of the interface between the cover layer 60 and the planarization layer 80.

[0069] Figure 6 , Figure 7 and Figure 8 Images of embodiments of a light control film showing nanocolumn features according to this specification. Specifically, these illustrate how the elongated portions of the planarization overcoat 80 can penetrate into the nanostructured facets 20 and into the light transmissive body 10.

[0070] Figure 6 An image showing a cross-section of a light control film according to an embodiment of the present disclosure. The smaller image is a closer view of the portion of the larger image indicated by the rectangular box on the larger image. The larger image shows the first facet 20 and the second facet 30 of the light transmissive body 10. The cover layer 60 is shown as substantially covering the second facet 30 but substantially not covering the first facet 20. The first facet 20 and the second facet 30 are covered by the planarization overcoat 80. As shown in the close-up image, the first facet 20 may include a plurality of nanocolumn features 40.

[0071] In some embodiments, at a plurality of spaced positions along at least the nanostructured first facet 20, the elongated portions 81 of the planarization overcoat 80 may penetrate the nanostructured facet 20 and enter the light transmissive body 10. In some embodiments, at least some of the elongated portions 81 may have a length greater than about 50 nm, or greater than about 100 nm, or greater than about 200 nm, or greater than about 500 nm, or greater than about 750 nm, or greater than about 1 micron, or greater than about 2 microns, or greater than about 3 microns, or greater than about 4 microns, or greater than about 5 microns, or greater than about 10 microns.

[0072] Figure 7Provides an even closer image of the surface of the first facet 20, where the coating layer 50 is more readily visible between the light-transmissive body 10 and the planarizing outer coating 80. In some embodiments, the elongate portions 81 corresponding to the same nanostructured first facet 20 may be substantially parallel to each other (as indicated by the dashed lines in the Figure 7 image).

[0073] Figure 8 is an additional image of the first facet 20, which shows the elongate portions 81 penetrating into the light-transmissive body 10. In some embodiments, at least some of the elongate portions 81 extend along a direction 82 that forms an angle θ4 with the normal 83 of the corresponding nanostructured first facet 20 that is greater than about 5 degrees, or greater than about 10 degrees, or greater than about 15 degrees.

[0074] Figure 9 Details a method for preparing a light control film (such as the Figure 1A light control film of this and other figures herein). In some embodiments, the method for preparing the light control film 100 includes Figure 9 the steps shown. Step 110 involves providing a light-transmissive body (such as the light-transmissive body 10 of FIG. 1), which includes a structured first major surface having a plurality of alternating first facets 20 and second facets 30. In some embodiments, step 110 may include disposing the light-transmissive body on a substrate 16.

[0075] Step 120 includes etching the structured first major surface of the light-transmissive body 10 such that each first facet 20 of the light-transmissive body 10 includes a plurality of nanocolumns 40 disposed across at least 70% of the first facet.

[0076] In some embodiments, step 120 may include depositing a mask layer before etching the structured first major surface. In some such embodiments, depositing the mask layer and etching the structured first major surface may be substantially simultaneous.

[0077] In step 130, a first material is deposited on the structured major surface to form a coating layer 50 (e.g., an etch stop layer), which coats the first facet 20 and the second facet 30 substantially conformally, so as to be substantially conformal with at least the nanocolumns 40 of the first facet 20.

[0078] In step 140, a light absorption layer 60 is deposited conformally on the coating layer 50.

[0079] In step 150, at least 70% of the light absorption layer 60 is removed from the first facet 20, while at least 70% of the light absorption layer 60 remains on the second facet 30.

[0080] In some embodiments, the method of preparing the light control film 100 may further include step 160, which includes conformally depositing a planarizing overcoat 80 that substantially planarizes the structured first major surface of the light transmissive body 10.

[0081] In some embodiments, the method of preparing the light control film 100 produces a minimum average peel strength greater than about 20 grams per inch between the planarizing overcoat and the coating layer. In some embodiments, for light incident on the light control film from a CIE standard light source D65, the light control film has an optical haze of less than about 30%.

[0082] Finally, Figure 10 A discussion of the following examples is provided, and a planarizing layer 80 disposed between the structured first major surface 11 of the light control film 300 and the substrate 95 is shown. The adhesion between the light control film 300 and the planarizing layer 80 can be tested using the component peel test procedure described elsewhere herein. In some embodiments, the peel test shows that Figure 10 the component shown fails at the interface 95a between the substrate 95 and the planarizing layer 80, rather than between the planarizing layer 80 and the structured first major surface 11 of the light control film 300.

[0083] Example

[0084] Unless otherwise indicated, all parts, percentages, ratios, etc. in the examples and the remainder of this specification are by weight.

[0085] Materials Used in the Example

[0086]

[0087] Method for Casting and Curing Microreplication to Prepare a Fresnel Lens Film

[0088] A tool with a coplanar microscale Fresnel lens structure is cut using diamond. Resin B is prepared by mixing the materials in Table 1 below.

[0089] Table 1: Composition of Resin B for Preparing a Microstructured Film

[0090] Material Parts by Weight PU2560 49.50 M210 49.50 Omnirad 4265 1.00

[0091] In a continuous casting and curing microreplication line, the "casting and curing" microreplication process is carried out using the above-mentioned resin B and tool. Resin B is heated to 100°F and coated onto a PET film with micro louvers on the opposite side. The louvers are protected by a PP pre-mask. The mold temperature during coating is 100°F. After coating, the coated film is passed through an IR heater at 130°F. Then the coated film is passed between a rubber pad roll and a Fresnel lens tool at a nip pressure of 18 psi and a tool temperature of 130°F. Three consecutive sets of Fusion D lamps are used to cure the resulting film at 100%, 60%, and 60% power respectively.

[0092] Method for Forming a Random Nanostructure

[0093] The surface of the microreplication film is modified using a homemade parallel plate capacitively coupled plasma reactor as described in U.S. Patent No. 6,696,157 (David et al.) and a one-pass random nanostructuring process as described in U.S. Patent No. 10,134,566 (David et al.). The chamber has a central cylindrical powered electrode with a surface area of 18.3 ft 2 After placing the microreplication film on the powered electrode, the reactor chamber is pumped down to a base pressure of less than 1.3 Pa (2 mTorr). O2 and HMDSO gases are introduced into the chamber at rates of 750 SCCM and 14 SCCM respectively. The treatment is carried out using a plasma-enhanced CVD method by coupling RF power to the reactor at a frequency of 13.56 MHz. The film is moved through the reaction zone at a rate of 7.5 fpm, resulting in a treatment time of approximately 40 seconds. After completing the process, the RF power is turned off and the chamber is returned to atmospheric pressure.

[0094] Method for Coating an Inorganic Etch Stop ("Coating Layer")

[0095] A silicon-containing resist is deposited using a homemade parallel plate capacitively coupled plasma reactor as described in U.S. Patent No. 6,696,157 (David et al.). The chamber has a central cylindrical powered electrode with a surface area of 18.3 ft 2 After placing the nanostructured mold film on the powered electrode, the reaction chamber is pumped down to a base pressure of less than 1.3 Pa (2 mTorr). O2 and HMDSO gases are introduced into the chamber at rates of 1500 SCCM and 300 SCCM respectively. The treatment is carried out using a plasma-enhanced CVD method by coupling RF power to the reactor at a frequency of 13.56 MHz and an applied power of 7500 watts. The film is moved through the reaction zone at a rate of 20 feet per minute, resulting in a treatment time of approximately 15 seconds. After completing the deposition, the RF power is turned off and the chamber is returned to atmospheric pressure.

[0096] Method for Coating a Light Absorbing Layer ("Covering Layer")

[0097] As described in U.S. Patent No. 10,926,289 (Kawakami et al.), a black light-absorbing coating is conformally coated on the Fresnel lens film by layer-by-layer (LbL) deposition on a coater. Two separate coating solutions are prepared: cationic and anionic. The cationic solution is 2.5% solids SC72 with 200 mM of NaCl and 0.1% of PL92 in deionized (DI) water. The anionic solution is 2.5% solids EXPCB with 50 mM of NaCl and 0.1% of PL92 in DI water. The light-absorbing coating structure consists of six bilayers, denoted as (SC72 / EXPCB)6. The microstructured film passes through the coating line. At each coating station, the cationic and anionic solutions are respectively coated onto the microstructured film with a #4 Mayer rod fed by a needle from a liquid delivery manifold at a flow rate of approximately 200 mL / min. After each deposition step, excess coating solution is removed from the web with an air knife spaced 40 mils from the web at a pressure of approximately 35 psi. The line speed is 50 feet per minute. The thickness of the LbL coating determined by analyzing SEM and TEM images with ImageJ software ranges from approximately 250 nm to 400 nm.

[0098] Method for Selectively Removing a Portion of the Light Absorbing Coating

[0099] In the same in-house reaction chamber used for depositing the PECVD release layer, reactive ion etching is performed on the coated film from step (4) to create nanostructures and an etch stop layer. After placing the coated film on the energized electrode, the reaction chamber is pumped down to a base pressure of less than 1.3 Pa (1 mTorr). O2 gas is flowed into the chamber at a rate of 1000 SCCM. Subsequently, 13.56 MHz RF power is coupled into the reactor with an applied power of 9000 W. Then the film is transported through the reaction zone at a rate of 1.5 ft / min to achieve an exposure time of approximately 200 seconds. At the end of this processing time, the RF power and gas supply are stopped, and the chamber is returned to atmospheric pressure.

[0100] Backfill Method

[0101] Resin A at 100°F is coated on the primed side of 2 mil PET, where a PP pre-mask is laminated to the back side of the PET at 30 fpm. The coating die temperature is also 100°F. Before lamination, the film is passed under an IR heater at 120°F. The structured film is introduced from a separate unwind and laminated to the coated PET film in a steel-rubber nip. The steel roll is heated to 140°F and the rubber roll is not heated.

[0102] When held on the steel roller, the laminate is then UV cured using two rows of Fusion D lamps, each row of lamps at 60% power. The cured laminate is removed from the steel roller using a take-off nip.

[0103] Method for Measuring Peel Strength

[0104] When as Figure 10 shown, when a planarization layer 80 is provided between the structured first major surface 11 of the light control film 300 and the substrate 95, the adhesion force between the light control film 300 and the planarization layer 80 can be tested using the assembly 450, using a 90-degree peel test (such as the test described in ASTM D6862-11(2021), but with some modifications). A strip of the film 450 sized 25 mm x 800 mm can be cut in a direction parallel to the linear prism direction. The substrate 95 can be attached to a rigid plate using 3M 665 double-sided tape, where the adhesive side of the tape is applied to the rigid plate and the substrate surface 99 can be adhered to the 665 tape. The louver side of the film is scribed to initiate peeling at the interface between the structured first major surface 11 of the light control film 300 and the planarization layer 80. Then the 3M 396 tape is aligned with the substrate and the rigid plate. The testing machine used is an Imass 2100. The inch section of the louver side is placed into the test machine jaws or clamps. This test is performed with a 10 lb load cell and a constant crosshead speed of 10 in / min for 5 seconds of average data collection.

[0105] Method for Acquiring Scanning Electron Microscope (SEM) Images

[0106] The sample is cryo-crushed using liquid nitrogen. Imaging is performed using a Hitachi S4700 field emission microscope. The images in this article are taken from the center of the Fresnel lens after backfill resin delamination. Method for Acquiring Transmission Electron Microscope (TEM) Images

[0107] Samples for TEM analysis are sectioned ultrathin at room temperature. The cutting thickness ranges between 100 nm and 130 nm. The sectioning cutting direction is chosen to be parallel or nearly parallel to most interfaces. TEM analysis is performed on a FEI-Osiris TEM operating at 200 kV. The STEM imaging mode is used. Bright field (BF), dark field (DF), and high angle annular dark field (HAADF) images are acquired. X-ray microanalysis is performed using a Bruker Super-X quadrupole x-ray SDD (silicon drift detector) and the attached Espirit quantification analysis software system.

[0108] CE1 No Etch Stop

[0109] Step 1: Prepare the microstructured film as described in the "Method of Casting and Curing Microreplication to Prepare a Fresnel Lens Film".

[0110] Step 2: Coating the microstructured film with a light-absorbing LBL layer as described in the "Method for Coating a Light-Absorbing Layer".

[0111] Step 3: Etching the light-absorbing layer as described in the "Method for Selectively Removing a Light-Absorbing Coating".

[0112] Step 4: Backfilling the structured film of Step 3 as described in the "Backfilling Method".

[0113] The peel values and haze measurements are recorded in Table 2.

[0114] CE2 Planar Etch Stop

[0115] Step 1: Preparing a microstructured film as described in the "Method for Casting and Curing Microreplication to Produce a Fresnel Lens Film".

[0116] Step 2: Applying an inorganic etch stop to the microstructured film as described in the "Method for Coating an Inorganic Etch Stop".

[0117] Step 3: Coating the microstructured film with a light-absorbing LBL layer as described in the "Method for Coating a Light-Absorbing Layer".

[0118] Step 4: Etching the light-absorbing layer as described in the "Method for Selectively Removing a Light-Absorbing Coating".

[0119] Step 5: Backfilling the structured film of Step 4 as described in the "Backfilling Method".

[0120] The peel values and haze measurements are recorded in Table 2.

[0121] EX 1 Structured Etch Stop

[0122] Step 1: Preparing a microstructured film as described in the "Method for Casting and Curing Microreplication to Produce a Fresnel Lens Film".

[0123] Step 2: Forming nanostructures on the surface of the structured film from Step 1 as described in the "Method for Forming Random Nanostructures".

[0124] Step 3: Applying an inorganic etch stop to the microstructured film as described in the "Method for Coating an Inorganic Etch Stop".

[0125] Step 4: Coating the microstructured film with a light-absorbing LBL layer as described in the "Method for Coating a Light-Absorbing Layer".

[0126] Step 5: Etching the light-absorbing layer as described in the "Method for Selectively Removing a Light-Absorbing Coating".

[0127] Step 6: Backfilling the structured film of Step 4 as described in the "Backfilling Method".

[0128] The peel values and haze measurements are recorded in Table 2.

[0129] Table 2. Example Conditions, Peel Values and Visual Grades

[0130]

[0131] Terms such as "about" will be understood in the context in which they are used and described by a person of ordinary skill in the art in this specification. If it is not clear to a person of ordinary skill in the art in the context in which they are used and described in this specification how "about" applies to a quantity expressing the size, amount, and physical properties of a feature, then "about" will be understood to mean within 10% of the specified value. A quantity given as about a specified value can be precisely the specified value. For example, if it is not clear to a person of ordinary skill in the art in the context in which they are used and described in this specification, a quantity having a value of about 1 means that the quantity has a value between 0.9 and 1.1, and the value can be 1.

[0132] A person of ordinary skill in the art will understand terms such as "substantially" in the context in which they are used and described in this specification. If it is not clear to a person of ordinary skill in the art in the context in which they are used and described in this specification how "substantially equal" is used, then "substantially equal" will mean about approximately the case of "about" as described above. If it is not clear to a person of ordinary skill in the art in the context in which they are used and described in this specification how "substantially parallel" is used, then "substantially parallel" will mean within 30 degrees of being parallel. In some embodiments, directions or surfaces described as being substantially parallel to each other can be within 20 degrees or 10 degrees of being parallel, or can be parallel or nominally parallel. If it is not clear to a person of ordinary skill in the art in the context in which they are used and described in this specification how "substantially aligned" is used, then "substantially aligned" will mean being aligned within 20% of the width of the object being aligned. In some embodiments, objects described as being substantially aligned can be aligned within 10% or 5% of the width of the object being aligned.

[0133] All of the above-referenced references, patents, and patent applications are hereby incorporated by reference in their entirety in a consistent manner. In the event of any inconsistency or contradiction between the incorporated reference section and this application, the information in the foregoing description shall prevail.

[0134] Unless otherwise indicated, descriptions of components in the figures are to be understood as equally applicable to corresponding components in other figures. Although specific embodiments have been illustrated and described herein, those of ordinary skill in the art will recognize that, without departing from the scope of the present disclosure, various alternative and / or equivalent specific implementations may be used in place of the specific embodiments shown and described herein. This application is intended to cover any modifications or variations of the specific embodiments discussed herein. Accordingly, the present disclosure is intended to be limited only by the claims and their equivalents.

Claims

1. A light - controlling film, the light - controlling film comprising a structured first major surface and a second major surface opposite thereto, the structured first major surface comprising a plurality of alternating first facets and second facets, each of the first facets in the first facets forms an average first angle with the second major surface that is less than about 90 degrees, and each of the second facets in the second facets forms an average second angle with the second major surface that is greater than about 60 degrees, etching at least each of the first facets in the plurality of first facets to form a plurality of first nano - structured facets, each of the first nano - structured facets comprising a plurality of nano - pillars, the plurality of nano - pillars being arranged across at least 70% of the first nano - structured facet and having different heights and aspect ratios; a coating layer, the coating layer being substantially conformally coated on the first facets and the second facets so as to be substantially conformal with at least the nano - pillars of the first nano - structured facet, the coating layer having an average thickness greater than about 5 nm and less than about 200 nm; and a cover layer, the cover layer being substantially conformally coated on a portion of the coating layer corresponding to the second facet and covering at least 70% of the portion of the coating layer, the cover layer having an average thickness greater than about 0.05 microns.

2. The light - controlling film according to claim 1, wherein at least 50% of the first facet is curved.

3. The light - controlling film according to claim 1, wherein at least 50% of the first facet is substantially planar.

4. The light - controlling film according to claim 1, wherein at least 60% of the second facet is substantially planar.

5. The light - controlling film according to claim 1, wherein the nano - pillars have a height in the range of about 1 nm to about 1000 nm.

6. The light - controlling film according to claim 1, wherein the nano - pillars have a width in the range of about 1 nm to about 1000 nm.

7. The light - controlling film according to claim 1, wherein at least one nano - pillar of at least one of the first nano - structured facets has an aspect ratio greater than 1.

5.

8. The light - controlling film according to claim 1, wherein the cover layer covers at most 40% of the coating layer corresponding to the first nano - structured facet.

9. The light - controlling film according to claim 1, wherein the cover layer is light - absorbing.

10. The light - controlling film according to claim 9, wherein the light - absorbing cover layer comprises a plurality of light - absorbing particles.

11. The light - controlling film according to claim 10, wherein the light - absorbing particles comprise one or more of dyes, pigments, polyelectrolytes, and carbon black.

12. The light - controlling film according to claim 9, wherein the light - absorbing cover layer has an optical density greater than about 0.

1.

13. The light - controlling film according to claim 1, the light - controlling film further comprising a light - transmissive body, the light - transmissive body comprising the structured first major surface and the opposite second major surface.

14. The light control film according to claim 1, wherein the first facet and the second facet are linear facets that extend along the length direction of the light control film and are arranged along the orthogonal width direction of the light control film.

15. The light control film according to claim 1, wherein the structured first major surface has a positive focal length for at least one visible wavelength within the visible wavelength range extending from about 420 nm to about 680 nm.

16. The light control film according to claim 1, the light control film further comprising a planarizing overcoat that conformally covers the structured first major surface and substantially planarizes the structured first major surface.

17. The light control film according to claim 16, wherein the minimum average peel strength between the planarizing overcoat and the coating layer is greater than about 20 grams per inch.

18. The light control film according to claim 16, wherein for light incident on the light control film from a CIE standard light source D65, the light control film has an optical haze of less than about 30%.

19. The light control film according to claim 16, the light control film further comprising a light transmissive body (10), the light transmissive body including the structured first major surface and the opposing second major surface, and wherein for at least one visible wavelength within the visible wavelength range extending from about 420 nm to about 680 nm, the magnitude of the difference between the refractive index of the light transmissive body and the planarizing overcoat is greater than about 0.05 and less than about 0.

5.

20. A display system, the display system comprising: The light control film according to claim 1, the light control film being disposed on a display configured to form an image; and a second light control film, the second light control film being disposed between the light control film and the display, the second light control film including a plurality of alternating substantially light transmissive regions and substantially light absorbing regions.

Images