WO2019079685A1 - Microstructured light guide plates and methods of manufacture - Google Patents

Abstract

Light guide plates comprising a glass-based substrate comprising an edge surface and a light emitting surface and a cured film of a resin composition comprising a UV-curable resin and a thermally-curable resin, the cured film comprising a plurality of microstructures disposed on the light emitting surface of the glass-based substrate. Methods of manufacturing light guide plates are also disclosed. Display and lighting devices comprising such light guide plates are further disclosed.

Description

MICROSTRUCTURED LIGHT GUIDE PLATES

AND METHODS OF MANUFACTURE

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C. § 1 19 of Korea Application No. 10-201 7-136561 filed on October 20, 2017, the content of which is relied upon and incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

[0002] The disclosure relates generally to light guide plates and display or lighting devices comprising such light guide plates, and more particularly to glass light guide plates comprising a microstructured cured film of a resin composition and methods for manufacturing the same.

BACKGROUND

[0003] Liquid crystal displays (LCDs) are commonly used in various electronics, such as cell phones, laptops, electronic tablets, televisions, and computer monitors. However, LCDs can be limited compared to other display devices in terms of brightness, contrast ratio, efficiency, and viewing angle. For example, to compete with other display technologies, there is a continuing demand for higher contrast ratio, color gamut, and brightness in conventional LCDs, while also balancing power requirements and device size (e.g., thickness).

[0004] LCDs can comprise a backlight unit (BLU) for producing light that can then be converted, filtered, and/or polarized to produce the desired image. BLUs may be edge-lit, e.g., comprising a light source coupled to an edge of a light guide plate (LGP), or direct-lit, e.g., comprising a two-dimensional array of light sources disposed behind the LCD panel. Direct-lit BLUs may have the advantage of improved dynamic contrast as compared to edge-lit BLUs. For example, a display with a direct-lit BLU can independently adjust the brightness of each LED to optimize the dynamic range of the brightness across the image. This is commonly known as local dimming. However, to achieve desired light uniformity and/or to avoid hot spots in direct-lit BLUs, the light source(s) may be positioned at a distance from the LGP, thus making the overall display thickness greater than that of an edge-lit BLU. In traditional edge-lit BLUs, the light from each LED can spread across a large region of the LGP such that turning off individual LEDs or groups of LEDs may have only a minimal impact on the dynamic contrast ratio.

[0005] The local dimming efficiency of an LGP can be enhanced, for example, by providing one or more microstructures on the LGP surface. For example, plastic LGPs, such as polymethyl methacrylate (PMMA) or methyl methacrylate styrene (MS) LGPs, can be fabricated with surface microstructures that may confine the light from each LED within a narrow band. In this way, it may be possible to adjust the brightness of the light source(s) along the edge of the LGP to enhance the dynamic contrast of the display. If LEDs are mounted on two opposing sides of the LGP, the brightness of pairs of LEDs can be adjusted to produce a brightness gradient along the bands of illumination that may further improve the dynamic contrast.

[0006] Methods for providing microstructures on plastic materials can include, for example, injection molding, extruding, and/or embossing. While these techniques may work well with plastic LGPs, they can be incompatible with glass LGPs due to their higher glass transition temperature and/or higher viscosity. However, glass LGPs may offer various improvements over plastic LGPs, e.g., in terms of their low light attenuation, low coefficient of thermal expansion, and high mechanical strength. As such, it may be desirable to use glass as an alternative material of construction for LGPs in order to overcome various drawbacks associated with plastics. For example, due to their relatively weak mechanical strength and/or lower stiffness, it can be difficult to make plastic LGPs that are both sufficiently large and thin to meet current consumer demands. Plastic LGPs may also necessitate a larger gap between the light source and LGP due to high coefficients of thermal expansion, which can reduce optical coupling efficiency and/or require a larger display bezel. Additionally, plastic LGPs may have a higher propensity to absorb moisture and swell as compared to glass LGPs.

[0007] Accordingly, it would be advantageous to provide glass LGPs with microstructures on at least one surface thereof. It would also be advantageous to provide methods of manufacturing glass LGPs with microstructures on at least one surface thereof. Glass light guide plates with microstructures on at least one surface thereof and manufacturing methods that provide improved optical performance, mechanical performance and reduced costs for such LGPs are also desired.

SUMMARY

[0008] A first aspect of the disclosure pertains to a light guide plate. In one embodiment, a light guide plate comprises a glass-based substrate comprising an edge surface and a light emitting surface, and a cured film of a resin composition comprising a UV-curable resin and a thermally-curable resin, the cured film comprising a plurality of microstructures disposed on the light emitting surface of the glass-based substrate. In another embodiment, a light guide plate comprises a glass-based substrate comprising an edge surface and a light emitting surface, and a cured film of a resin composition comprising a UV-curable resin and an infrared- curable resin, the cured film comprising a plurality of microstructures disposed on the light emitting surface of the glass-based substrate, wherein at least one of the a UV- curable resin and the infrared-curable resin comprises a silicone-terminated polymer.

[0009] A second aspect of the disclosure pertains to a method of manufacturing a light guide plate, the method comprising mixing a UV-curable resin and a thermally- curable resin to form a resin composition; applying a layer of the resin composition to a glass-based substrate; curing the layer to form a film; and forming a plurality of microstructures on the film.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The following detailed description can be further understood when read in conjunction with the following drawings.

[0011] FIGS. 1A-D illustrate exemplary microstructure arrays according to various embodiments of the disclosure;

[0012] FIG. 2 illustrates a light guide assembly according to certain embodiments of the disclosure;

[0013] FIG. 3 is a graphical depiction of light confinement as a function of microstructure aspect ratio for a 1 D local dimming configuration using a light guide plate having a microstructured surface comprising an array of lenticular lenses; [0014] FIG. 4 is a graphical depiction of color shift Ay as a function of the ratio of blue to red transmission for a light guide plate;

[0015] FIG. 5 is a graphical depiction of transmission curves for various light guide plates;

[0016] FIG. 6 is a depiction of bonding between a resin film composition and a glass-based substrate;

[0017] FIG. 7 is a graph of color shift data for a sample before and after aging;

[0018] FIG. 8 is a graph for two different samples comparing color shift before and after aging;

[0019] FIG. 9 is graph showing estimated color shift for the data in FIG. 8

[0020] FIG. 10 is a graph of color shift data for several samples; and

[0021] FIG. 1 1 is a graph of color shift variability data.

DETAILED DESCRIPTION

[0022] Described herein are light guide plates and light guide assemblies comprising a light guide plate including a glass-based substrate comprising an edge surface and a light emitting surface and a cured film of a resin composition comprising a UV-curable resin and a thermally-curable resin, the cured film comprising a plurality of microstructures disposed on the light emitting surface of the glass-based substrate. Light guide assemblies further comprise at least one light source optically coupled to the edge surface of the glass-based substrate.

[0023] As used herein, the terms "glass-based article" and "glass-based substrates" are used in their broadest sense to include any object made wholly or partly of glass. Glass-based articles include laminates of glass and non-glass materials, laminates of glass and crystalline materials, and glass-ceramics (including an amorphous phase and a crystalline phase). Unless otherwise specified, all glass compositions are expressed in terms of mole percent (mol%).

[0024] The light guide plates and light guide assemblies described herein can be utilized in displays, lighting, and electronic devices, e.g., televisions, computers, phones, tablets, and other display panels, luminaires, solid-state lighting, billboards, and other architectural elements.

[0025] It was determined that ultraviolet (UV) curable resin on a glass-based substrate applied by a roll coat method, which requires manual deposition of resin on the surface of a glass-based substrate, resulted in pressurizing the resin, and the resin overflowed on the glass-based substrate. Formation of a straight film edge was difficult to achieve using the roll coat method. It was also difficult to control the thickness of the UV-curable resin applied to a glass-based substrate, and the mechanical properties of the UV cured resin were not acceptable.

[0026] It was discovered that a resin composition comprised of a mixture of UV- curable resin and thermally-curable resin overcame the difficulties discussed above in the manufacture of light guide plates. According to one or more embodiments, methods of manufacturing light guide plates are provided that are suitable for in-line manufacturing processes. As used herein, "in-line" refers to a process that can be incorporated with another manufacturing process, for example, a glass-based sheet manufacturing process such as a down draw process for manufacturing glass sheets. Examples of suitable in-line coating methods include extrusion coating, direct gravure coating, reverse gravure coating, die coating, spray-coating, and slit coating methods. In one or more embodiments, the resin compositions described herein exhibit excellent heat and humidity resistance. In specific embodiments, silicone synthesized resins are utilized in the composition to provide excellent heat and humidity resistance. According to one or more embodiments, the inclusion of a thermally-curable resin in the composition provides a cured film of a resin composition that exhibits excellent mechanical performance compared with a cured resin film comprised of only a UV-curable resin. Furthermore, one or more embodiments provide a light guide plate with excellent optical performance, as the cured resin composition has a stable structure that exhibits minimal structural disorientation during curing.

[0027] Thus, according to one or more embodiments, light guide plates are manufactured by applying a resin composition that allows lenticular patterning on the glass-based substrate surface to provide sufficient optical properties for glass LGP and reliability in high temperature and humidity as well as mechanical robustness. In one or more embodiments a method is provided that allows lenticular patterning with easy and fast curing, allowing for an automated LGP manufacturing system that could serve as a paradigm-shift in LGP manufacturing.

[0028] Thus, a first embodiment pertains to a light guide plate comprising a glass- based substrate comprising an edge surface and a light emitting surface, and a cured film of a resin composition comprising a UV-curable resin and a thermally- curable resin, the cured film comprising a plurality of microstructures disposed on the light emitting surface of the glass-based substrate. In a second embodiment, the thermally-curable resin comprises an infrared-curable resin. In a third embodiment, the first or second embodiment is such that the UV-curable resin comprises an acrylate-based polymer. In a fourth embodiment, the third embodiment is such that the acrylate-based polymer comprises a monomer selected from the group consisting of trimethylolpropane (EO)3 triacrylate, trimethylolpropane triacrylate, isobornyl acrylate, acrylate, and combinations thereof. In a fifth embodiment, the third embodiment is such that the acrylate-based polymer comprises a silicone- terminated polyacrylate. In a sixth embodiment, the infrared-curable resin of any of the first through fifth embodiments comprises a (meth)acrylate-based polymer, for example, a methyl methacrylate or a silicone-terminated poly(meth)acrylate.

[0029] In a seventh embodiment, the light guide plate of the first through sixth embodiments comprises a combined light attenuation a' of less than about 5 dB/m for wavelengths ranging from about 420-750 nm. In an eighth embodiment, the light guide plate of the first through seventh embodiments comprises a color shift Ay of less than about 0.015. In a ninth embodiment, the light guide plate of the first through eighth embodiments has a glass-based substrate which comprises, on a mol% oxide basis: 50-90 mol% Si0₂, 0-20 mol% Al₂0₃, 0-20 mol% B₂0₃, and 0-25 mol% RxO, wherein x is 2 and R is chosen from Li, Na, K, Rb, Cs, and combinations thereof, or wherein x is 1 and R is chosen from Zn, Mg, Ca, Sr, Ba, and

combinations thereof. In a tenth embodiment, the glass-based substrate of the first through ninth embodiments comprises less than about 1 ppm each of Co, Ni, and Cr.

[0030] In an eleventh embodiment, a thickness di of the glass-based substrate of the first through tenth embodiments ranges from about 0.1 mm to about 3 mm. In a twelfth embodiment of a light guide plate, a thickness d₂ of the cured film of the first through eleventh embodiments ranges from about 10 μιη to about 500 μιη. In a thirteenth embodiment of a light guide plate, the plurality of microstructures of the first through twelfth embodiments comprises a periodic or non-periodic array of prisms, rounded prisms, or lenticular lenses. In a fourteenth embodiment, at least one microstructure in the plurality of microstructures of the thirteenth embodiment comprises an aspect ratio ranging from about 0.1 to about 3. [0031] In a fifteenth embodiment of the light guide plate of the first through fourteenth embodiments, the glass-based substrate further comprises a plurality of light extraction features patterned on a major surface of the glass-based substrate opposite the light emitting surface.

[0032] Another aspect of the disclosure pertains to a light guide assembly comprising the light guide plate of any of the first through fifteenth embodiments and at least one light source optically coupled to an edge surface of the glass-based substrate. The assembly may further comprise at least one second light source optically coupled to a second edge surface of the glass-based substrate and, optionally, a second cured film of a resin composition comprising a plurality of microstructures disposed on a major surface of the glass-based substrate opposite the light emitting surface.

[0033] Another aspect of the disclosure pertains to a display, lighting, or electronic device comprising the assemblies which include the light guide plates described in this disclosure.

[0034] An alternative embodiment pertains to a light guide plate comprising a glass- based substrate comprising an edge surface and a light emitting surface; and a cured film of a resin composition comprising a UV-curable resin and an infrared- curable resin, the cured film comprising a plurality of microstructures disposed on the light emitting surface of the glass-based substrate, wherein at least one of the UV- curable resin and the infrared-curable resin comprises a silicone-terminated polymer. In one or more embodiments, the resin composition can be processed to form a lenticular pattern and the cured film is resistant to heat. Another aspect of the disclosure pertains to a light guide assembly comprising the light guide plate described according to the alternative embodiment and at least one light source optically coupled to an edge surface of the glass-based substrate. The assembly may further comprise at least one second light source optically coupled to a second edge surface of the glass-based substrate and, optionally, a second cured film of a resin composition comprising a plurality of microstructures disposed on a major surface of the glass-based substrate opposite the light emitting surface. Another aspect of the disclosure pertains to a display, lighting, or electronic device

comprising the assemblies which include the light guide plates described in this disclosure. [0035] Various embodiments of the disclosure will now be discussed with reference to FIGS. 1 A-D and FIG. 2, which illustrate exemplary embodiments of light guide plates. The following general description is intended to provide an overview of the claimed devices, and various aspects will be more specifically discussed throughout the disclosure with reference to the non-limiting depicted embodiments.

[0036] FIGS. 1 A-D and FIG. 2 illustrate various exemplary embodiments of a light guide plate (LGP) 100 comprising a glass-based substrate 1 10 and a cured film of a resin composition 120 comprising a UV-curable resin and a thermally-curable resin. The cured film of a resin composition 120 comprises a plurality of microstructures 130. In FIGS. 1A-B the microstructures 130 comprise prisms 132 and rounded prisms 134, respectively. As shown in FIG. 1 C, the microstructures 130 may also comprise lenticular lenses 136. Of course, the depicted microstructures are exemplary only and are not intended to limit the appended claims. Other microstructure shapes are possible and intended to fall within the scope of the disclosure. Furthermore, while FIGS. 1A-C illustrate regular (or periodic) arrays, it is also possible to use an irregular (or non-periodic) array. For example, FIG. 1 D is an SEM image of a microstructured surface comprising a non-periodic array of prisms.

[0037] As used herein, the term "microstructures," "microstructured," and variations thereof is intended to refer to surface relief features of the cured film of a resin composition having at least one dimension (e.g., height, width, length, etc.) that is less than about 500 μιη, such as less than about 400 μιη, less than about 300 μιη, less than about 200 μιη, less than about 100 μιη, less than about 50 μιη, or even less, e.g., ranging from about 10 μιη to about 500 μιη, including all ranges and subranges therebetween. The microstructures may, in certain embodiments, have regular or irregular shapes, which can be identical or different within a given array. While FIGS. 1A-D generally illustrate microstructures 130 of the same size and shape, which are evenly spaced apart at substantially the same pitch, it is to be understood that not all microstructures within a given array must have the same size and/or shape and/or spacing. Combinations of microstructure shapes and/or sizes may be used, and such combinations may be arranged in a periodic or non-periodic fashion.

[0038] Moreover, the size and/or shape of the microstructures 130 can be varied depending on the desired light output and/or optical functionality of the LGP. For example, different microstructure shapes may result in different local dimming efficiencies, also referred to as the local dimming index (LDI). By way of non-limiting example, a periodic array of prism microstructures may result in an LDI value up to about 70%, whereas a periodic array of lenticular lenses may result in an LDI value up to about 83%. Of course, the microstructure size and/or shape and/or spacing may be varied to achieve different LDI values. Different microstructure shapes may also provide additional optical functionalities. For example, a prism array having a 90° prism angle may not only result in more efficient local dimming, but may also partially focus the light in a direction perpendicular to the prismatic ridges due to recycling and redirecting of the light rays.

[0039] With reference to FIG. 1A, the prism microstructures 132 can have a prism angle Θ ranging from about 60^° to about 120^°, such as from about 70^° to about 1 10^°, from about 80^° to about 100^°, or about 90^°, including all ranges and subranges therebetween. Referring to FIG. 1 C, the lenticular lens microstructures 136 can have any given cross-sectional shape (as illustrated by the dashed lines), ranging from semi-circular, semi-elliptical, parabolic, or other similar rounded shapes.

[0040] Referring now to FIG. 2 a light guide assembly is shown including at least one light source 140 that can be optically coupled to an edge surface 150 of the glass-based substrate 1 10, e.g., positioned adjacent to the edge surface 150. As used herein, the term "optically coupled" is intended to denote that a light source is positioned at an edge of the LGP so as to introduce light into the LGP. A light source may be optically coupled to the LGP even though it is not in physical contact with the LGP. Additional light sources (not illustrated) may also be optically coupled to other edge surfaces of the LGP, such as adjacent or opposing edge surfaces.

[0041] A general direction of light emission from light source 140 is depicted in FIG. 2 by the solid arrow. Light injected into the LGP may propagate along a length L of the LGP due to total internal reflection (TIR), until it strikes an interface at an angle of incidence that is less than the critical angle. TIR is the phenomenon by which light propagating in a first material (e.g., glass, plastic, etc.) comprising a first refractive index can be totally reflected at the interface with a second material (e.g., air, etc.) comprising a second refractive index lower than the first refractive index. TIR can be explained using Snell's law:

n_{ sin(#_;) = n₂ sm(6_r) which describes the refraction of light at an interface between two materials of differing indices of refraction. In accordance with Snell's law, ni is the refractive index of a first material, n∑ is the refractive index of a second material, θ , is the angle of the light incident at the interface relative to a normal to the interface (incident angle), and Θ _r is the angle of refraction of the refracted light relative to the normal. When the angle of refraction (Θ _r) is 90°, e.g., sin(0 _r) = 1 , Snell's law can be expressed as:

0_{c =} 0_{. = s}jn-ⁱ(_¾ )

The incident angle θ , under these conditions may also be referred to as the critical angle Θ _c. Light having an incident angle greater than the critical angle (θ , > Θ _c) will be totally internally reflected within the first material, whereas light with an incident angle equal to or less than the critical angle (θ , < Θ _c) will be transmitted by the first material.

[0042] In the case of an exemplary interface between air

-5), the critical angle (0 _C) can be calculated as 41 °. Thus, if light propagating in the glass strikes the air-glass interface at an incident angle greater than 41 °, all the incident light will be reflected from the interface at an angle equal to the incident angle. If the reflected light encounters a second interface comprising an identical refractive index relationship as the first interface, the light incident on the second interface will again be reflected at a reflection angle equal to the incident angle.

[0043] Cured film composition 120 may be disposed on a major surface of the glass-based substrate 1 10, such as light emitting surface 160. The array of microstructures 130 may, along with other optional components of the LGP, direct the transmission of light in a forward direction (e.g., toward a user), as indicated by the dashed arrows. In some embodiments, light source 140 may be a Lambertian light source, such as a light emitting diode (LED). Light from the LEDs may spread quickly within the LGP, which can make it challenging to effect local dimming (e.g., by turning off one or more LEDs). However, by providing one or more

microstructures on a surface of the LGP that are elongated in the direction of light propagation (as indicated by the solid arrow in FIG. 2), it may be possible to limit the spreading of light such that each LED source effectively illuminates only a narrow strip of the LGP. The illuminated strip may extend, for example, from the point of origin at the LED to a similar end point on the opposing edge. As such, using various microstructure configurations, it may be possible to effect one dimensional (1 D) local dimming of at least a portion of the LGP in a relatively efficient manner.

[0044] In certain embodiments, the light guide assembly can be configured such that it is possible to achieve two dimensional (2D) local dimming. For example, one or more additional light sources can be optically coupled to an adjacent (e.g., orthogonal) edge surface. A first cured film of a resin composition may be arranged on the light emitting surface having microstructures extending in a propagation direction, and a second cured film of a resin composition may be arranged on the opposing major surface, this film comprising microstructures extending in a direction orthogonal to the propagation direction. Thus, 2D local dimming may be achieved by selectively shutting off one or more of the light sources along each edge surface.

[0045] According to various embodiments, the surface 160 or second major surface 170 of the glass-based substrate 1 10 may be patterned with a plurality of light extraction features. As used herein, the term "patterned" is intended to denote that the plurality of light extraction features is present on or in the surface of the substrate in any given pattern or design, which may, for example, be random or arranged, repetitive or non-repetitive, uniform or non-uniform. In other embodiments, the light extraction features may be located within the matrix of the glass-based substrate adjacent the surface, e.g., below the surface. For example, the light extraction features may be distributed across the surface, e.g., as textural features making up a roughened or raised surface, or may be distributed within and throughout the substrate or portions thereof, e.g., as laser-damaged features. Suitable methods for creating such light extraction features can include printing, such as inkjet printing, screen printing, microprinting, and the like, texturing, mechanical roughening, etching, injection molding, coating, laser damaging, or any combination thereof. Non-limiting examples of such methods include, for example, acid etching a surface, coating a surface with Ti0₂, and laser damaging the substrate by focusing a laser on a surface or within the substrate matrix.

[0046] In various embodiments, the light extraction features optionally present on the surface 160 or second major surface 170 of the LGP may comprise light scattering sites. According to various embodiments, the light extraction features may be patterned in a suitable density so as to produce substantially uniform light output intensity across the light emitting surface of the glass-based substrate. In certain embodiments, a density of the light extraction features proximate the light source may be lower than a density of the light extraction features at a point removed from the light source, or vice versa, such as a gradient from one end to another, as appropriate to create the desired light output distribution across the LGP.

[0047] The LGP may be treated to create light extraction features according to any method known in the art, e.g., the methods disclosed in co-pending and co-owned International Patent Application Publication Nos. WO2014058748 and

WO2015095288, each incorporated herein by reference in their entirety. For example, a surface of the LGP may be ground and/or polished to achieve the desired thickness and/or surface quality. The surface may then be optionally cleaned and/or the surface to be etched may be subjected to a process for removing contamination, such as exposing the surface to ozone. The surface to be etched may, by way of a non-limiting embodiment, be exposed to an acid bath, e.g., a mixture of glacial acetic acid (GAA) and ammonium fluoride (NH₄F) in a ratio, e.g., ranging from about 1 :1 to about 9:1 . The etching time may range, for example, from about 30 seconds to about 15 minutes, and the etching may take place at room temperature or at elevated temperature. Process parameters such as acid concentration/ratio, temperature, and/or time may affect the size, shape, and distribution of the resulting extraction features. It is within the ability of one skilled in the art to vary these parameters to achieve the desired surface extraction features.

[0048] The glass-based substrate 1 10 can have any desired size and/or shape as appropriate to produce a desired light distribution. The glass-based substrate 1 10 may comprise a second major surface 170 opposite the light emitting surface 160. The major surfaces may, in certain embodiments, be planar or substantially planar, e.g., substantially flat. The first and second major surfaces may, in various embodiments, be parallel or substantially parallel. The glass-based substrate 1 10 may comprise four edges as illustrated in FIG. 2, or may comprise more than four edges, e.g. a multi-sided polygon. In other embodiments, the glass-based substrate 1 10 may comprise less than four edges, e.g., a triangle. By way of a non-limiting example, the light guide plate may comprise a rectangular, square, or rhomboid sheet having four edges, although other shapes and configurations are intended to fall within the scope of the disclosure including those having one or more curvilinear portions or edges.

[0049] In certain embodiments, the glass-based substrate 1 10 may have a thickness di of less than or equal to about 3 mm, for example, ranging from about 0.1 mm to about 3 mm, from about 0.1 mm to about 2.5 mm, from about 0.3 mm to about 2 mm, from about 0.5 mm to about 1 .5 mm, or from about 0.7 mm to about 1 mm, including all ranges and subranges therebetween. The glass-based substrate 1 10 can comprise any material known in the art for use in display devices. For example, the glass-based substrate may comprise aluminosilicate, alkali- aluminosilicate, borosilicate, alkali-borosilicate, aluminoborosilicate, alkali- aluminoborosilicate, soda lime, or other suitable glasses. Non-limiting examples of commercially available glasses suitable for use as a glass light guide include, for example, EAGLE XG^®, Lotus™, Willow^®, Iris™, and Gorilla^® glasses from Corning Incorporated.

[0050] Some non-limiting glass compositions can include between about 50 mol % to about 90 mol% Si0₂, between 0 mol% to about 20 mol% Al₂0₃, between 0 mol% to about 20 mol% B₂03, and between 0 mol% to about 25 mol% R_xO, wherein R is any one or more of Li, Na, K, Rb, Cs and x is 2, or Zn, Mg, Ca, Sr or Ba and x is 1 . In some embodiments, R_xO - Al₂0₃ > 0; 0 < R_xO - Al₂0₃ < 15; x = 2 and R₂0 - Al₂0₃ < 15; R₂0 - Al₂0₃ < 2; x=2 and R₂0 - Al₂0₃ - MgO > -15; 0 < (R_xO - Al₂0₃) < 25, - 1 1 < (R₂0 - Al₂0₃) < 1 1 , and -15 < (R₂0 - Al₂0₃ - MgO) < 1 1 ; and/or -1 < (R₂0 - Al₂0₃) < 2 and -6 < (R₂0 - Al₂0₃ - MgO) < 1 . In some embodiments, the glass comprises less than 1 ppm each of Co, Ni, and Cr. In some embodiments, the concentration of Fe is < about 50 ppm, < about 20 ppm, or < about 10 ppm. In other embodiments, Fe + 30Cr + 35Ni < about 60 ppm, Fe + 30Cr + 35Ni < about 40 ppm, Fe + 30Cr + 35Ni < about 20 ppm, or Fe + 30Cr + 35Ni < about 10 ppm. In other embodiments, the glass comprises between about 60 mol % to about 80 mol% Si0₂, between about 0.1 mol% to about 15 mol% Al₂0₃, 0 mol% to about 12 mol% B₂0₃, and about 0.1 mol% to about 15 mol% RxO and about 0.1 mol% to about 15 mol% RxO, wherein R is any one or more of Li, Na, K, Rb, Cs and x is 2, or Zn, Mg, Ca, Sr or Ba and x is 1 .

[0051] In other embodiments, the glass composition can comprise between about 65.79 mol % to about 78.17 mol% Si0₂, between about 2.94 mol% to about 12.12 mol% AI2O3, between about 0 mol% to about 1 1 .16 mol% B2O3, between about 0 mol% to about 2.06 mol% Li₂0, between about 3.52 mol% to about 13.25 mol% Na₂0, between about 0 mol% to about 4.83 mol% K₂0, between about 0 mol% to about 3.01 mol% ZnO, between about 0 mol% to about 8.72 mol% MgO, between about 0 mol% to about 4.24 mol% CaO, between about 0 mol% to about 6.17 mol% SrO, between about 0 mol% to about 4.3 mol% BaO, and between about 0.07 mol% to about 0.1 1 mol% Sn0₂.

[0052] In additional embodiments, the glass-based substrate 1 10 can comprise an R_xO/AI₂03 ratio between 0.95 and 3.23, wherein R is any one or more of Li, Na, K, Rb, Cs and x is 2. In further embodiments, the glass-based substrate may comprise an R_xO/AI₂03 ratio between 1 .18 and 5.68, wherein R is any one or more of Li, Na, K, Rb, Cs and x is 2, or Zn, Mg, Ca, Sr or Ba and x is 1 . In yet further embodiments, the glass-based substrate can comprise an R_xO - AI2O3 - MgO between -4.25 and 4.0, wherein R is any one or more of Li, Na, K, Rb, Cs and x is 2. In still further embodiments, the glass-based substrate may comprise between about 66 mol % to about 78 mol% Si0₂, between about 4 mol% to about 1 1 mol% AI2O3, between about 4 mol% to about 1 1 mol% B2O3, between about 0 mol% to about 2 mol% Li₂0, between about 4 mol% to about 12 mol% Na₂0, between about 0 mol% to about 2 mol% K₂0, between about 0 mol% to about 2 mol% ZnO, between about 0 mol% to about 5 mol% MgO, between about 0 mol% to about 2 mol% CaO, between about 0 mol% to about 5 mol% SrO, between about 0 mol% to about 2 mol% BaO, and between about 0 mol% to about 2 mol% Sn0₂.

[0053] In additional embodiments, the glass-based substrate 1 10 can comprise between about 72 mol % to about 80 mol% Si0₂, between about 3 mol% to about 7 mol% AI2O3, between about 0 mol% to about 2 mol% B2O3, between about 0 mol% to about 2 mol% Li₂0, between about 6 mol% to about 15 mol% Na₂0, between about 0 mol% to about 2 mol% K₂0, between about 0 mol% to about 2 mol% ZnO, between about 2 mol% to about 10 mol% MgO, between about 0 mol% to about 2 mol% CaO, between about 0 mol% to about 2 mol% SrO, between about 0 mol% to about 2 mol% BaO, and between about 0 mol% to about 2 mol% Sn0₂. In certain embodiments, the glass-based substrate can comprise between about 60 mol % to about 80 mol% Si0₂, between about 0 mol% to about 15 mol% AI2O3, between about 0 mol% to about 15 mol% B2O3, and about 2 mol% to about 50 mol% R_xO, wherein R is any one or more of Li, Na, K, Rb, Cs and x is 2, or Zn, Mg, Ca, Sr or Ba and x is 1 , and wherein Fe + 30Cr + 35Ni < about 60 ppm.

[0054] In some embodiments, the glass-based substrate 1 10 can comprise a color shift Ay less than 0.015, such as ranging from about 0.005 to about 0.015 (e.g., about 0.005, about 0.006, about 0.014, or about 0.01 5). In other embodiments, the glass-based substrate can comprise a color shift less than about 0.008. According to certain embodiments, the glass-based substrate can have a light attenuation αι (e.g., due to absorption and/or scattering losses) of less than about 4 dB/m, such as less than about 3 dB/m, less than about 2 dB/m, less than about 1 dB/m, less than about 0.5 dB/m, less than about 0.2 dB/m, or even less, e.g., ranging from about 0.2 dB/m to about 4 dB/m, for wavelengths ranging from about 420 nm to about 750 nm.

[0055] The glass-based substrate 1 10 may, in some embodiments, be chemically strengthened, e.g., by ion exchange. During the ion exchange process, ions within a glass sheet at or near the surface of the glass sheet may be exchanged for larger metal ions, for example, from a salt bath. The incorporation of the larger ions into the glass can strengthen the sheet by creating a compressive stress in a near surface region. A corresponding tensile stress can be induced within a central region of the glass sheet to balance the compressive stress.

[0056] Ion exchange may be carried out, for example, by immersing the glass in a molten salt bath for a predetermined period of time. Exemplary salt baths include, but are not limited to, KNO3, L1 NO3, NaNC>3, RbNC>3, and combinations thereof. The temperature of the molten salt bath and treatment time period can vary. It is within the ability of one skilled in the art to determine the time and temperature according to the desired application. By way of a non-limiting example, the temperature of the molten salt bath may range from about 400°C to about 800°C, such as from about 400°C to about 500°C, and the predetermined time period may range from about 4 to about 24 hours, such as from about 4 hours to about 10 hours, although other temperature and time combinations are envisioned. By way of a non-limiting example, the glass can be submerged in a KNO3 bath, for example, at about 450°C for about 6 hours to obtain a K-enriched layer which imparts a surface compressive stress.

[0057] The cured film of a resin composition 120 can comprise a thermally-curable resin and a UV-curable resin. The resins used in the cured film of a resin composition may further be chosen from resins having a low color shift and/or low absorption of blue light wavelengths (e.g., ~450-500nm), as discussed in more detail below. In certain embodiments, the cured film of a resin composition 120 may be thinly deposited on the light emitting surface of the glass-based substrate. The cured film of a resin composition 120 may be continuous or discontinuous.

[0058] Referring to FIGS. 1 A-C, the cured film of a resin composition 120 may have an overall thickness d₂ and a "land" thickness t. In certain embodiments, the microstructures 130 may comprise peaks p and valleys v, and the overall thickness may correspond to the height of the peaks p relative to the surface 160 of the glass- based substrate, whereas the land thickness may correspond to the height of the valleys v relative to the surface 160 of the glass-based substrate. According to various embodiments, it may be advantageous to deposit the cured film of a resin composition 120 such that the land thickness t is zero or as close to zero as possible. When t is zero, the cured film of a resin composition 120 may be discontinuous. For example, the land thickness t may range from 0 to about 250 μιη, such as from about 10 μιη to about 200 μιη, from about 20 μιη to about 150 μιη, or from about 50 μιη to about 100 μιη, including all ranges and subranges

therebetween. In additional embodiments, the overall thickness d₂ may range from about 10 μιη to about 500 μιη, such as from about 20 μιη to about 400 μιη, from about 30 μιη to about 300 μιη, from about 40 μιη to about 200 μιη, or from about 50 μιη to about 100 μιη, including all ranges and subranges therebetween.

[0059] With continued reference to FIGS. 1A-C, the microstructures 130 may also have a width w, which can be varied as desired to achieve a desired light output. For example, FIG. 3 illustrates the effect of aspect ratio (w/[d₂-t]) on light confinement for a 1 D dimming configuration. Normalized power is plotted to represent the ability to efficiently confine light in a given width zone. For the illustrated configuration (LGP thickness = 2.5 mm; microstructures = elliptical lenticular lenses), the aspect ratio corresponding to maximum dimming effectiveness for a 200 mm width zone (circle data points) is approximately 2.5. Similarly, the aspect ratio for achieving maximum dimming in a 100 mm width zone (square data points) is approximately 2.3.

[0060] Accordingly, in some embodiments, the width w and/or overall thickness d may be varied to obtain a desired aspect ratio. Variation of the land thickness t can also be used to modify the light output. In non-limiting embodiments, the aspect ratio of the microstructures 130 can range from about 0.1 to about 3, such as from about 0.5 to about 2.5, from about 1 to about 2.2, or from about 1 .5 to about 2, including all ranges and subranges therebetween. According to some embodiments, the aspect ratio can range from about 2 to about 3, e.g., about 2, about 2.1 , about 2.2, about 2.3, about 2.4, about 2.5, about 2.6, about 2.7, about 2.8, about 2.9, or about 3, including all ranges and subranges therebetween. The width w of the

microstructures can also range, for example, from about 1 μιη to about 250 μιη, such as from about 10 μιη to about 200 μιη, from about 20 μιη to about 150 μιη, or from about 50 μιη to about 100 μιη, including all ranges and subranges therebetween. It should also be noted that the microstructures 130 may have a length (not labeled) extending in the direction of light propagation (see solid arrow in FIG. 2), which can vary as desired, e.g., depending on the length L of the glass-based substrate.

[0061] The cured film of a resin composition 120 may, in certain embodiments, comprise a material that does not exhibit a noticeable color shift. Several plastics and resins may have a tendency to develop a yellow tint over time due to light absorption of blue wavelengths (e.g., -450-500 nm). This discoloration may worsen at elevated temperatures, for example, within normal BLU operating temperatures. Moreover, BLUs incorporating LED light sources may exacerbate the color shift due to significant emission of blue wavelengths. In particular, LEDs may be used to deliver white light by coating a blue-emitting LED with a color converting material (such as phosphors, etc.) that converts some of the blue light to red and green wavelengths, resulting in the overall perception of white light. However, despite this color conversion, the LED emission spectrum may still have a strong emission peak in the blue region. If the cured film of a resin composition absorbs the blue light, it may be converted to heat, thereby further accelerating polymer degradation and further increasing blue light absorption over time.

[0062] While absorption of blue light by the cured film of a resin composition 120 may be negligible when light propagates perpendicular to the film, it may become more significant when light propagates along the length of the film (as in the case of an edge-lit LGP), due to the longer propagation length. Blue light absorption along the length of the LGP may result in a noticeable loss of blue light intensity and, thus, a noticeable change of color (e.g., a yellow color shift) along the propagation direction. As such, a color shift may be perceived by the human eye from one edge of the display to the other. It may therefore be advantageous to select cured film of a resin composition materials that have comparable absorption values for different wavelengths within the visible range (e.g., -420-750 nm). For example, the absorption at blue wavelengths may be substantially similar to the absorption at red wavelengths, and so forth.

[0063] FIG. 4 demonstrates the impact of the blue/red transmission ratio on color shift for an LGP. As demonstrated by the plot, color shift Ay increases in a nearly linear fashion as blue (450 nm) transmission decreases relative to red (630 nm) transmission. As blue transmission approaches a value similar to that of red transmission (e.g., as the ratio approaches 1 ), the color shift Ay similarly approaches 0. FIG. 5 illustrates the transmission spectra used to produce the correlation presented in FIG. 4. Table I below provides relevant details for transmission curves

Table I: Transmission Curves

[0064] Because the cured film of a resin composition may comprise only a small portion of the overall thickness of the LGP, the blue/red transmission ratio can be somewhat lower than that show in FIG. 4 (due to the relative thinness of the film) without dramatically impacting color shift performance of the overall LGP. However, it may still be desirable to reduce absorption of blue light and/or to provide a more homogenous absorption profile across the visible wavelength spectrum. For example, the individual resins that comprise the cured film of a resin composition may be selected to avoid chromophores that absorb at wavelengths > 450 nm. In certain embodiments, the individual resins of the cured film of a resin composition may be chosen such that the concentration of blue light absorbing chromophores is less than about 5 ppm, such as less than about 1 ppm, less than about 0.5 ppm, or less than about 0.1 ppm, including all ranges and subranges therebetween.

Alternatively, the cured film of a resin composition 120 may be modified to compensate for blue light absorption, e.g. by incorporating one or more dyes, pigments, and/or optical brighteners that absorb at yellow wavelengths (e.g., -570- 590 nm) to neutralize any potential color shift. However, engineering the cured film of a resin composition to absorb both at blue and yellow wavelengths may lower the overall transmissivity of the film and, thus, the overall transmissivity of the LGP. As such, in certain embodiments, it may be advantageous to instead select and/or modify the cured film of a resin composition to reduce blue light absorption and thereby increase the overall transmissivity of the film.

[0065] According to various embodiments, the cured film of a resin composition 120 may also be chosen to have a refractive index dispersion that balances interfacial Fresnel reflections in the blue and red spectral regions to minimize color shift along the length of the LGP. For example, the difference in Fresnel reflections at the substrate-cured film of a resin composition interface at 45^° for wavelengths between about 450 nm and about 630 nm may be less than about 0.015%, such as less than about 0.005%, or less than about 0.001 %, including all ranges and subranges therebetween. Other relevant dispersion characteristics are described in co-pending U.S. Provisional Application No. 62/348465, filed June 10, 2016, and entitled "Glass Articles Comprising Light Extraction Features," which is incorporated herein by reference in its entirety.

[0066] Referring again to FIG. 2, in various embodiments, the cured film of a resin composition 120 may be molded to the light emitting surface 160 of the glass-based substrate 1 10. For example, during and/or after coating the glass-based substrate with the polymeric material, the film composition may be imprinted or embossed with a desired surface pattern. This process may be referred to as "micro-replication," in which a desired pattern is first manufactured as a mold and then pressed into the film composition to yield a negative replica of the mold shape. The polymeric material may be UV cured or thermally cured during or after imprinting, which may be referred to as "UV embossing" and "thermal embossing," respectively.

Alternatively, the film composition may be applied using hot embossing techniques, in which the polymeric material is first heated to a temperature above its glass transition point, followed by imprinting and cooling. Other methods may include printing (e.g., screen printing, inkjet printing, microprinting, etc.) or extruding a layer of polymeric material onto the glass-based substrate and subsequently shaping (e.g., molding, embossing, imprinting, etc.) the layer to the desired shape.

[0067] According to various embodiments, the glass-based substrate 1 10 may comprise compositions having a first glass transition temperature T_gi that is greater than a second glass transition temperature T_g2 of the cured film of a resin

composition 120. For example, a difference between the glass transition

temperatures (T_gi-T_g2) may be at least about 100 ^°C, such as ranging from about 100 ^°C to about 800 ^°C, from about 200 ^°C to about 700 ^°C, from about 300 ^°C to about 600 ^°C, or from about 400 ^°C to about 500 ^°C, including all ranges and subranges therebetween. This temperature differential may allow the polymeric material to be molded to the glass-based substrate without melting or otherwise negatively impacting the glass-based substrate during the molding process. In other embodiments, the glass-based substrate may have a first melting temperature T_mi that is greater than a second melting temperature T_m2 of the cured film of a resin composition and/or a first viscosity vi that is greater than a second viscosity V2 of the cured film of a resin composition at a given processing temperature.

[0068] The glass-based substrate, cured film of a resin composition, and/or LGP can, in certain embodiments is transparent or substantially transparent. As used herein, the term "transparent" is intended to denote that the substrate, film, or LGP has an optical transmission of greater than about 80% in the visible region of the spectrum (~420-750nm). For example, an exemplary transparent material may have greater than about 85% transmittance in the visible light range, such as greater than about 90%, greater than about 95%, or greater than about 99% transmittance, including all ranges and subranges therebetween. In certain embodiments, an exemplary transparent material may have an optical transmittance of greater than about 50% in the ultraviolet (UV) region (~100-400nm), such as greater than about 55%, greater than about 60%, greater than about 65%, greater than about 70%, greater than about 75%, greater than about 80%, greater than about 85%, greater than about 90%, greater than about 95%, or greater than about 99% transmittance, including all ranges and subranges therebetween. [0069] In some embodiments, an exemplary transparent glass or polymeric material can comprise less than 1 ppm each of Co, Ni, and Cr. In some embodiments, the concentration of Fe is < about 50 ppm, < about 20 ppm, or < about 10 ppm. In other embodiments, Fe + 30Cr + 35Ni < about 60 ppm, Fe + 30Cr + 35Ni < about 40 ppm, Fe + 30Cr + 35Ni < about 20 ppm, or Fe + 30Cr + 35Ni < about 10 ppm. According to additional embodiments, an exemplary transparent glass or polymeric material can comprise a color shift < 0.015 or, in some embodiments, a color shift < 0.008.

[0070] Color shift may be characterized by measuring variation in the x and y chromaticity coordinates along the length L using the CIE 1931 standard for color measurements. For glass light-guide plates the color shift Ay can be reported as

where L₂ and Li are Z positions along the panel or substrate direction away from the source launch and where

meters. Exemplary light-guide plates have Ay< 0.01 , Ay< 0.005, Ay < 0.003, or Ay < 0.001 .

[0071] The optical light scattering characteristics of the LGP may also be affected by the refractive index of the glass and polymeric materials. According to various embodiments, the glass may have a refractive index ranging from about 1 .3 to about 1 .8, such as from about 1 .35 to about 1 .7, from about 1 .4 to about 1 .65, from about 1 .45 to about 1.6, or from about 1 .5 to about 1 .55, including all ranges and subranges therebetween. In some embodiments, the polymeric material may have an index of refraction substantially similar to that of the glass-based substrate. As used herein, the term "substantially similar" is intended to denote that two values are approximately equal, e.g., within about 10% of each other, such as within about 5% of each other, or within about 2% of each other in some cases. For example, in the case of a refractive index of 1 .5, a substantially similar refractive index may range from about 1 .35 to about 1 .65.

[0072] According to various non-limiting embodiments, the LGP (glass + polymer) may have a relatively low level of light attenuation (e.g., due to absorption and/or scattering). For example, a combined attenuation for the LGP may be expressed as a' = (di/D)*ai + (d₂/D)*a2, in which di represents the overall thickness of the transparent substrate, d₂ represents the overall thickness of the cured film of a resin composition, D represents the overall thickness of the LGP (D=di+d₂), αι represents the attenuation value of the transparent substrate, and a₂ represents the attenuation value of the cured film of a resin composition. In certain embodiments, a' may be less than about 5 dB/m for wavelengths ranging from about 420 nm to about 750 nm. For example, a' may be less than about 4 dB/m, less than about 3 dB/m, less than about 2 dB/m, less than about 1 dB/m, less than about 0.5 dB/m, less than about 0.2 dB/m, or even less, including all ranges and subranges therebetween, e.g., from about 0.2 dB/m to about 5 dB/m. The combined attenuation of the LGP may vary depending, e.g., upon the thickness of the cured film of a resin composition and/or the ratio of overall polymer film thickness to overall LGP thickness (d₂/D). As such, the cured film of a resin composition thickness and/or glass-based substrate thicknesses may be varied to achieve a desired attenuation value. For example, (d₂/D) may range from about 1 /2 to about 1/50, such as from about 1/3 to about 1 /40, from about 1/5 to about 1/30, or from about 1 /10 to about 1/20, including all ranges and subranges therebetween.

[0073] The LGPs disclosed herein may be used in various display devices including, but not limited to LCDs. According to various aspects of the disclosure, display devices can comprise at least one of the disclosed LGPs optically coupled to at least one light source, which may emit blue, UV, or near-UV light (e.g.,

approximately 100-500 nm). In some embodiments, the light source may be a light emitting diode (LED). The optical components of an exemplary LCD may further comprise a reflector, a diffuser, one or more prism films, one or more linear or reflecting polarizers, a thin film transistor (TFT) array, a liquid crystal layer, and one or more color filters, to name a few components. The LGPs disclosed herein may also be used in various illuminating devices, such as luminaires or solid state lighting devices.

[0074] Another aspect of the disclosure pertains to a method of manufacturing a light guide plate comprising mixing a UV-curable resin and a thermally-curable resin to form a resin composition; applying a layer of the resin composition to a glass- based substrate; curing the layer to form a film; and forming a plurality of

microstructures on the film. The thermally-curable resin in some embodiments comprises an infrared-curable resin. In one or more embodiments, the UV-curable resin comprises an acryl ate- based polymer. The acrylate-based polymer in some embodiments comprises a monomer selected from the group consisting of:

trimethylolpropane (EO)3 triacrylate, trimethylolpropane triacrylate, isobornyl acrylate, acrylate, and combinations thereof. In one or more embodiments, the acrylate-based polymer comprises a silicone-terminated polyacrylate. In some embodiments, the infrared-curable resin comprises a (meth)acrylate-based polymer, for example, a polymethyl methacrylate. In some embodiments, the (meth)acrylate- based polymer comprising a silicone-terminated poly(meth)acrylate.

[0075] In one or more method embodiments, curing includes heating the layer of the resin composition to a temperature in a range of from about 60° to about 200° C, for example, about 60° to about 190° C, about 60° to about 180° C, about 70° to about 190° C, about 70° to about 1 80° C, about 80° to about 190° C, about 80° to about 180° C, about 690° to about 190° C, about 90° to about 180° C, about 100° to about 190° C, about 100° to about 180° C, about 1 10° to about 190° C, or about 1 10° to about 180° C. In one or more embodiments, the curing time is fast, that is in a range of 2 seconds to 30 seconds, 2 seconds to 25 seconds, 2 seconds to 20 seconds, 2 seconds to 15 seconds or 2 seconds to 10 seconds. Prior to curing the resin composition layer may be dried for a period of time from about 2 to about 10 minutes in air or in a commercial drying apparatus for about 10 seconds to about 60 seconds. In one or more embodiments, UV curing can be achieved using any suitable UV light source for curing UV-curable resins.

[0076] In one or more embodiments, the plurality of microstructures formed by the method comprises a periodic or non-periodic array of prisms, rounded prisms, or lenticular lenses. In one or more embodiments, at least one microstructure in the plurality of microstructures formed by the method comprises an aspect ratio ranging from about 0.1 to about 3.

[0077] Suitable solvents that can be used to form the resin compositions include ketones such as ethyl ethyl ketone methyl isobutyl ketone, acetone, and alcohols such as ethyl alcohol.

[0078] Non-limiting examples of components of the UV-curable resin can include trimethylpropane triacrylate, trimethylolpropane (EO)3 triacrylate or other acrylate monomers, and isobornyl acrylate.

[0079] Non-limiting examples of components of the thermally-curable resin can include 2-MD (acrylate monomer with MEK), 3-MD (acrylate oligomer with MEK) available from Chemieplus.

[0080] EXAMPLES

[0081] Example 1A-Formation of Resin Composition The following components were prepared to form a resin composition:

UV curable resin: trimethylolpropane (EO)3 triacrylate (TMP(EO)3TA), Isobornyl acrylate (ibxa), M3001 (acrylate monomer, available from Chemieplus).

Thermally Curable (IR) resin: 2-MD (acrylate monomer with MEK), 3-MD (acrylate oligomer with MEK)

Photoinitiator: Darocur 1 173 (, 2-Hydroxy-2-methyl-1 -phenyl-propan-1 -one, available from Ciba Specialty Chemicals)

Additives: Glide-100 (available from Evonik), Efka® SL 3031 (available from BASF) Solvent: methyl ethyl ketone (MEK)

[0082] While the disclosure should not be bound by any particular theory or principle, it is believed that the UV curable resin provides appropriate viscosity for lenticular patterning. It is believed that the thermally curable IR resin provides mechanical properties such as hardness and resistance to heat. It is believed that silicone added resins (2-MD and 3-MD) provide more enhanced robustness for heat and humidity for the cured resin composition. A photoinitiator is used for initiating chain reaction by directing an ultraviolet (UV) light source such as an UV LED to activate a radical reaction for acrylate polymerization. Glide-100 and Efka SL 3031 were additives, which enhanced the flat surface by making more dense film structures and preventing surface craters.

[0083] Silicone resin formation can be achieved by any suitable way, for example, by hydrolyzing an organosilane such as acryl silane to form highly reactive silanol groups. Then, these silanol groups condense to form oligomeric siloxane structures. In a specific example, silicone-added resin was prepared as follows:

a. Acrylate silane(1 0) to H₂0(1 ) and acetic acid (0.1 ) were mixed (by weight ratio) (mixture of part a).

b. 2-MD was heated up to a temperature 75°C.

c. The mixture of part "a" was added to the 2-MD heated to 75°C in a reaction vessel.

d. Reaction vessel temperature was increased due to reaction adding the mixture of part a.

e. When the reaction was complete, no further heat change was observed and the mixture was maintained at 75°C. 3-MD and M3001 , which are acrylate monomers, were also prepared in the same manner as steps a-e above.

All components were added by % weight as shown below:

MEK - 57.4

TMP- 9.2

2- MD 18.4

3- MD- 9.2

IBXA- 0.4

M3001 - 4.6

1 173D 0.4

3031 0.1

G-100 0.3

[0084] Small scale mixing is done in either a glass pot with a Teflon mixing bar, or a stainless steel beaker. When a stainless steel beaker is used, a stainless steel mixing blade can be used. Oligomers, monomers, and photoinitiator were mixed at 60 °C using a hot oil bath. The mixture was allowed to cool to room temperature. Mixing is done at about 600 rpm to ensure homogeneity.

[0085] The resin was filtered with a capsule 0.45μιη filter into a clean container.

[0086] Example I B-Manual Coating on Glass Substrate

[0087] A relatively small sized glass test was performed to check the basic performance of the resin composition. The mixed resin according to Example 1 was prepared in a beaker, which was poured directly onto a glass substrate to coat the glass substrate with the resin composition. The coated substrate was placed in an air drier for 10 to 30 seconds to dry off MEK solvent. A lenticular patterned PET film (called soft mold) was used to cover the glass substrate and the lenticular patterned PET film was pressed a hand roller. While maintaining the PET film over the glass substrate, a UV LED (365 nm) lamp source was used to cure the resin composition surface with 150 mJ of radiation for two seconds. After UV curing was complete, the PET film was removed, and a hot plate was used to heat the substrate to 1 10 °C temperature for 2 minutes to cure the IR resin component.

[0088] Example 1 C-Lenticular patterning in line process half on a 55" Glass Substrate [0089] A resin composition according to Example 1 A was used to form a coating layer on a 55 inch glass substrate using a slit coater with nitrogen pressure at 25 KPa to spray the resin on the surface at a velocity of 150 mm/s to form 20 urn thickness of resin coating layer.

[0090] The coated glass was dried in atmospheric conditions for 2 minutes and 30 seconds to evaporate MEK solvent. 400mJ energy was used for UV curing in an imprinter with a belt type stamper. The conditions for the stamper were 3000 mm/s of velocity with 29.4 N of pressure for rolling a soft mold. For thermal curing, a conveyor type IR heater was used to irradiate the coating for 2 min, to provide a stable heat region at a temperature of 130 °C. During the thermal curing step, condensation of resin with glass was as shown in Fig. 6.

[0091] After glass surface treatment for lenticular patterning of this sample, the sample was extraction patterned on the side opposite the coated/lenticular-patterned side to maximize glass luminance. Color index (Cx, Cy) and luminance of the sample was measured. In addition, pencil hardness, adhesion, and chemical reaction were evaluated on the lenticular pattern.

[0092] Target values, resin film performance and the results are shown below:

[0093] Color shift is a key criterion for determining LGP optical performance. Color shift metric is taken from the Max-Min(Cy) which represent white to yellow color change index. Cy was measured 1 10 points on the lenticular patterned LGP reflected by a UV LED lamp. The low color shift range represents the degree of changing color to yellow along the glass vertical direction to the LED. Performance of LGP plates made from glass substrates and resins that comprised only UV resins resulted in a Color shift of 0.020-0.025, which is much higher than the instant example comprising a thermally curable resin and a UV curable resin. [0094] Adhesion was tested by a cross hatch test according to ASTM Standard D- 3359-76 and DIN Standard No. 53151 . Although the target was GT1 , the sample prepared in accordance with Example 1 B showed the highest level of adhesion performance (GTO).

[0095] Pencil hardness was tested in accordance with ASTM D3363-00, to evaluate scratch resistance of the surface and met the target performance of 1 H. Chemical resistance was tested using Electrochemical Impedance Spectroscopy (EIS) by dipping the samples in the chemical according to CAS No.: 64741-66-8 to evaluate chemical resistance of the surface. The test showed no chemical reaction observation with CAS No.: 64741 -66-8 chemical, which is commonly used for testing chemicals used in a LGP cleaning process.

[0096] Color shift performance was evaluated. The table below shows the color shift contribution of extraction pattern and lenticular film lenticular pattern by the resin.

Color Shift Range

Max (Cy)-Max (Cy) in 1 10 Points

[0097] All samples were measured for extraction patterning first and measured again with lenticular films. The Table shows color shift from lenticular film Δ C/S is less than 0.003, which is superior performance for color shift. A contour plot showed the color shift (Cy) of resin, showing shift value increase along the accumulation of light from inlet to reflection side.

[0098] Color shift was also measured after aging. The data is shown in FIG. 7, under test conditions of aging in a chamber for 72 hours at 60 °C and 90% relative humidity. After aging, the sample made according to Example 1 B showed little increase in color shift range and it was still <0.015. [0099] To simulate more severe aging (humidity and heat) conditions, samples made in accordance with Example 1 B were boiled with water for 30 minutes.

Transmittance was measured before and after boiling to see the effect of the silicone. The top graph in FIG. 8 is before the addition of a silicone-terminated polymer, and the bottom graph shows a sample including a silicone-terminated polymer. The sample without a silicone-terminated polymer showed that

transmittance was significantly decreased after boiling. However, the sample containing a silicone-terminated polymer showed smaller gap between before and after boiling than without the sample without as silicone-terminated polymer.

[00100] FIG. 9 shows a predicted color shift behavior before and after boiling for comparison with the data in FIG. 8. The resin without silicone showed almost 0.02 range of color shift change. But a silicone-containing resin showed a range of color shift of 0.005 even after boiling. This is more severe aging condition than the general 60 °C/90% aging condition, and shows a very significant improvement over known resin-coated glass-based substrates that can be patterned and used as LGPs.

[00101] While silicone-containing resins provide good resistance to thermal and weathering degradation, likely due to the bond strength difference between Si-0 (108 Kcal/mole) and C-C (82.6kcal/mole), a resin that does not contain silicone provides more linear structure and fast curing time. It has been discovered that a mixture of the two resins can provide a resin composition such that the two resins compensate for the drawbacks of each resin when used individually, providing synergistic effects in a composite resin composition containing both types of resins.

[00102] Robustness and repeatability of resin compositions as described herein were tested in an in-line manufacturing test. FIG. 10 shows the variation between different samples along the x-axis for 133 measurements. All samples showed a color shift range below 0.015, demonstrating a very robust performance of resin in terms of optical properties. FIG. 1 1 shows the process capability of the resin compositions according to the present disclosure, showing shift: mean 0.0079, Cpk=2.41 , Sigma level: 8.75, indicating that the resin performance is very robust between different process runs and suitable for mass production.

[00103] Examples 2A, 2B and 3

[00104] Resin compositions were prepared in the same manner as in Example 1 , with the following compositions.

[00105] Manual coating on glass substrates and lenticular patterning was conducted with Examples 2A, 2B and 3 in a similar manner to Examples 1 A and 1 B. The color shift of these compositions was also measured before and after aging by measuring five samples before and after aging. The data below represents color shift after aging in a chamber for 72 hours at 60 °C and 90% relative humidity.

Example 2A 0.01 15 0.0135

Example 2B 0.0100 0.0085

Example 3 (Si 7%) 0.0090 0.0095

[00106] Lower color shift (CS) after aging indicates better optical performance, because lower CS equates with lower Cy change in LGPs along the vertical direction which is perpendicular to the LED source direction.

[00107] After aging, the samples made according to Examples 2A, 2B and 3 showed little increase in color shift range and CS was still <0.015. In particular, Examples 2B and 3 showed minimal CS, indicating reliability despite temperature and humidity aging.

[00108] It will be appreciated that the various disclosed embodiments may involve particular features, elements or steps that are described in connection with that particular embodiment. It will also be appreciated that a particular feature, element or step, although described in relation to one particular embodiment, may be interchanged or combined with alternate embodiments in various non-illustrated combinations or permutations.

[00109] It is also to be understood that, as used herein the terms "the," "a," or "an," mean "at least one," and should not be limited to "only one" unless explicitly indicated to the contrary. Thus, for example, reference to "a light source" includes examples having two or more such light sources unless the context clearly indicates otherwise. Likewise, a "plurality" or an "array" is intended to denote "more than one." As such, a "plurality of light scattering features" includes two or more such features, such as three or more such features, etc., and an "array of microstructures" includes two or more such microstructures, such as three or more such microstructures, and so on.

[00110] Ranges can be expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, examples include from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. [00111] The terms "substantial," "substantially," and variations thereof as used herein are intended to note that a described feature is equal or approximately equal to a value or description. For example, a "substantially planar" surface is intended to denote a surface that is planar or approximately planar.

[00112] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that any particular order be inferred.

[00113] Various modifications and variations can be made to the materials, methods, and articles described herein. Other aspects of the materials, methods, and articles described herein will be apparent from consideration of the specification and practice of the materials, methods, and articles disclosed herein. It is intended that the specification and examples be considered as exemplary. It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosure.

Claims

WHAT IS CLAIMED IS:

1 . A light guide plate comprising:

a glass-based substrate comprising an edge surface and a light emitting surface; and

a cured film of a resin composition comprising a UV-curable resin and a thermally-curable resin, the cured film comprising a plurality of microstructures disposed on the light emitting surface of the glass-based substrate.

2. The light guide plate of claim 1 , wherein the thermally-curable resin comprises an infrared-curable resin.

3. The light guide plate of claim 1 , wherein the UV-curable resin comprises an acrylate-based polymer.

4. The light guide plate of claim 3, wherein the acrylate-based polymer comprises a monomer selected from the group consisting of: tnmethylolpropane (EO)3 triacrylate, tnmethylolpropane triacrylate, isobornyl acrylate, acrylate, and combinations thereof.

5. The light guide plate of claim 3, wherein the acrylate-based polymer comprises a silicone-terminated polyacrylate.

6. The light guide plate of claim 2, wherein the infrared-curable resin comprises a (meth)acrylate-based polymer.

7. The light guide plate of claim 6, wherein the infrared-curable resin comprises a polymethylmethacrylate.

8. The light guide plate of claim 6, wherein the (meth)acrylate-based polymer comprises a silicone-terminated poly(meth)acrylate.

9. The light guide plate of any of claims 1 -8, wherein the light guide plate comprises a combined light attenuation a' of less than about 5 dB/m for wavelengths ranging from about 420 nm to about 750 nm.

10. The light guide plate of any of claims 1 -9, wherein the light guide plate comprises a color shift Ay of less than about 0.015.

1 1 . The light guide plate of any of claims 1 -10, wherein the glass-based substrate comprises, on a mol% oxide basis:

50-90 mol% Si0₂,

0-25 mol% RxO,

wherein x is 2 and R is chosen from Li, Na, K, Rb, Cs, and combinations thereof, or wherein x is 1 and R is chosen from Zn, Mg, Ca, Sr, Ba, and

combinations thereof.

12. The light guide plate of claim 1 1 , wherein the glass-based substrate comprises less than about 1 ppm each of Co, Ni, and Cr.

13. The light guide plate of claim 1 , wherein a thickness di of the glass-based substrate ranges from about 0.1 mm to about 3 mm.

14. The light guide plate of claim 13, wherein an overall thickness d₂ of the cured film ranges from about 1 0 μιη to about 500 μιη.

15. The light guide plate of claim 1 , wherein the plurality of microstructures comprises a periodic or non-periodic array of prisms, rounded prisms, or lenticular lenses.

16. The light guide plate of claim 15, wherein at least one microstructure in the plurality of microstructures comprises an aspect ratio ranging from about 0.1 to about 3.

17. The light guide plate of claim 1 , wherein the glass-based substrate further comprises a plurality of light extraction features patterned on a major surface of the glass-based substrate opposite the light emitting surface.

18. A light guide assembly comprising the light guide plate of any of claims 1 -17 and at least one light source optically coupled to the edge surface of the glass-based substrate.

19. The assembly of claim 18, further comprising at least one second light source optically coupled to a second edge surface of the glass-based substrate and, optionally, a second cured film of a resin composition comprising a plurality of microstructures disposed on the major surface of the glass-based substrate opposite the light emitting surface.

20. A display, lighting, or electronic device comprising the assembly of claim 18.

21 . A light guide plate comprising:

a glass-based substrate comprising an edge surface and a light emitting surface; and

a cured film of a resin composition comprising a UV-curable resin and an infrared-curable resin, the cured film comprising a plurality of microstructures and disposed on the light emitting surface of the glass-based substrate, wherein at least one of the UV-curable resin and the infrared-curable resin comprises a silicone- terminated polymer.

22. A method of manufacturing a light guide plate comprising:

mixing a UV-curable resin and a thermally-curable resin to form a resin composition;

applying a layer of the resin composition to a glass-based substrate;

curing the layer to form a film; and

forming a plurality of microstructures on the film.

23. The method of claim 22, wherein the thermally-curable resin comprises an infrared-curable resin.

24. The method of claim 22, wherein the UV-curable resin comprises an acrylate- based polymer.

25. The method of claim 24, wherein the acrylate-based polymer comprises a monomer selected from the group consisting of: trimethylolpropane (EO)3 triacrylate, trimethylolpropane triacrylate, isobornyl acrylate, acrylate, and combinations thereof.

26. The method of claim 24, wherein the acrylate-based polymer comprises a silicone-terminated polyacrylate.

27. The method of claim 23, wherein the infrared-curable resin comprises a (meth)acrylate-based polymer.

28. The method of claim 27, wherein the infrared-curable resin comprises a methyl methacrylate.

29. The method of claim 27, wherein the (meth)acrylate-based polymer comprises a silicone-terminated poly(meth)acrylate.

30. The method of claim 22, wherein curing includes heating the layer of the resin composition to a temperature in a range of from about 100° to about 200° C.

31 . The method of claim 22, wherein the plurality of microstructures comprises a periodic or non-periodic array of prisms, rounded prisms, or lenticular lenses.

32. The method of claim 31 , wherein at least one microstructure in the plurality of microstructures comprises an aspect ratio ranging from about 0.1 to about 3.