WO2019236516A1 - Glass articles including elongate polymeric microstructures - Google Patents

Abstract

Light guide plates are disclosed that can be used in a backlight unit suitable for use as an illuminator for liquid crystal display devices and methods for their manufacture are disclosed. The light guide plates can comprise a plurality of elongate polymeric microstructures on a major surface of a glass substrate. The microstructures can be polymeric multilayer microstructures to provide lenticular features.

Description

GLASS ARTICLES INCLUDING ELONGATE POLYMERIC MICRO STRUCTURES

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S.

Provisional Application Serial No. 62/682315 filed on June 8, 2018, the content of which is relied upon and incorporated herein by reference in its entirety.

BACKGROUND

[0002] The present disclosure relates generally to a glass article which can be used as a light guide plate in a backlight unit for illuminating a liquid crystal display device, and in particular, a glass article that can be used as light guide plate in a backlight unit configured for one-dimensional dimming.

[0003] While organic light emitting diode (OLED) display devices are gaining in popularity, costs to produce these display devices are still high, and liquid crystal display (LCD) devices still comprise the large majority of display devices sold, particularly large panel size devices, such as television sets and other large-format devices such as commercial signs. Unlike OLED display panels, LCD panels do not themselves emit light, and are therefore dependent on a backlight unit (BLU) including a light guide plate (LGP) positioned behind the LCD panel to provide transmissive light to the LCD panel. Light from the BLU illuminates the LCD panel and the LCD panel functions as a light valve that selectively allows light to pass through pixels of the LCD panel or be blocked, thereby forming a viewable image.

[0004] Without augmentation, the native contrast ratio achievable with an LCD display is the ratio of the brightest portion of an image to the darkest portion of the image. The simplest contrast augmentation occurs by increasing the overall illumination for a bright image, and decreasing the overall illumination for a dark image. Unfortunately, this leads to muted brights in a dark image, and washed out darks in a bright image. To overcome this limitation, manufacturers can incorporate active local dimming of the image, wherein the illumination within predefined regions of the display can be locally dimmed relative to other regions of the display panel, depending on the image being displayed. Such local dimming can be relatively easily incorporated when the light source is positioned directly behind the LCD panel, for example a two dimensional array of LEDs. Local dimming is more difficult to incorporate with an edge lighted BLU, wherein an array of LEDs is arranged along an edge of a light guide plate incorporated into the BLU.

[0005] Typical light guide plates incorporate a polymer light guide, such as poly methyl methacrylate (PMMA). PMMA is easily formed, and can be molded or machined to facilitate local dimming. However, PMMA can suffer from thermal degradation, comprises a relatively large coefficient of thermal expansion, suffers from moisture absorption and is easily deformed. On the other hand, glass is dimensionally stable (comprises a relatively low coefficient of thermal expansion), and can be produced in large thin sheets suitable for the growing popularity of large, thin TVs.

[0006] Accordingly, it would be desirable to produce BLUs that include thin glass light guide plates capable of facilitating local dimming. Furthermore, it would be desirable to provide glass LGPs having improved local dimming efficiency, e.g., glass LGPs with microstructures on at least one surface thereof which can reduce color shift but also address conventional reliability issues. It would also be advantageous to provide backlights having a thickness similar to that of edge-lit BLUs while also providing local dimming capabilities similar to that of back-lit BLUs.

SUMMARY

[0007] A first aspect of the disclosure pertains to a light guide plate comprising a glass substrate including an edge surface and two major surfaces; and a plurality of elongate polymeric multilayer micro structures on at least one of the major surfaces, each elongate multilayer micro structure having a maximum height H and a width W measured at one-half of the maximum height (H/2) and further comprising an aspect ratio W/H in a range of from about 0.1 to about 10.

[0008] A second aspect of the disclosure pertains to a light guide plate comprising a glass substrate including an edge surface and at least two major surfaces; and a plurality of elongate polymeric micro structures on at least one of the major surfaces, each elongate polymeric microstructure comprising a surface slope angle of less than 15 degrees, and wherein the surface slope angle is defined by an angle formed between a line parallel to the light emitting surface of the glass substrate and a line extending between a first uppermost surface of the elongate polymeric microstructure at maximum height Hi and a second uppermost surface of the elongate polymeric micro structure at minimum height H_2. [0009] A third aspect of the disclosure pertains to a method of manufacturing a light guide plate comprising depositing a first layer of curable liquid on a major surface of a glass substrate as a first array of elongate liquid beads; at least partially curing with radiation the first layer of curable liquid to provide an array of at least partially cured elongate

microstructures spaced apart by distance S; depositing a second layer of curable liquid on the first array at least partially cured elongate beads as a second array of elongate liquid beads; at least partially curing with radiation the second layer of curable liquid to provide a two layer array of at least partially cured elongate microstructures; and optionally forming an additional layer of curable liquid on the two layer array of at least partially cured elongate

microstructures to provide a multilayer array of elongate polymeric multilayer

microstructures comprising n layers, wherein n is in a range of from 2 to 10.

[0010] A fourth aspect of the disclosure pertains to a method of forming a light guide plate comprising depositing a curable liquid on a major surface of a glass substrate to provide an array of elongate, spaced apart first curable liquid layers; at least partially curing the array of elongate, spaced apart curable liquid layers to form an array of spaced apart at least partially cured polymeric layers; depositing additional curable liquid on the array of spaced apart at least partially cured polymeric layers to form an array of elongate, spaced apart second curable liquid layers; at least partially curing the array of elongate, spaced apart second curable liquid layers to form an array of at least partially cured elongate polymeric multilayer microstructures; and optionally forming an additional array of at least partially cured elongate polymeric micro structures on the array of at least partially cured elongate polymeric multilayer micro structures so that the array of at least partially cured elongate polymeric multilayer microstructures comprises n layers, wherein n is in a range of from 2 to 10.

[0011] Additional features of the embodiments disclosed herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0012] The accompanying drawings are included to provide further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure and together with the description serve to explain the principles and operations thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is a cross-sectional view of an exemplary LCD display device;

[0014] FIG. 2 is a top view of an exemplary light guide plate;

[0015] FIG. 3 A is a cross-sectional view of a glass substrate comprising a plurality of polymeric multilayer microstructures on a surface thereof and suitable for use with the glass light guide plate of FIG. 2;

[0016] FIG. 3B is a cross-sectional view of another glass substrate comprising a plurality of polymeric multilayer microstructures on a surface thereof and suitable for use with the glass light guide plate of FIG. 2;

[0017] FIG. 3C is a cross-sectional view of still another glass substrate comprising a plurality of polymeric multilayer micro structures on a surface thereof and suitable for use with the glass light guide plate of FIG. 2;

[0018] FIG. 3D is a cross-sectional view of still another glass substrate comprising a plurality of polymeric multilayer micro structures on a surface thereof and suitable for use with the glass light guide plate of FIG. 2;

[0019] FIG. 3E is a cross-sectional view of still another glass substrate comprising a plurality of polymeric multilayer microstructures on a polymeric platform on a surface thereof and suitable for use with the glass light guide plate of FIG. 2;

[0020] FIG. 3F is an SEM image of a microstructured surface comprising a non-periodic array of polymeric multilayer prisms;

[0021] FIG. 4 illustrates a light guide plate according to certain embodiments of the disclosure;

[0022] FIG. 5 illustrates a polymeric multilayer microstructure according to certain embodiments of the disclosure;

[0023] FIG. 6A illustrates a polymeric multilayer microstructure according to certain embodiments of the disclosure;

[0024] FIG. 6B is a graph of contact angle as function of aspect ratio, W/H according to an embodiment;

[0025] FIG. 7A is a schematic view of a stable, undisturbed continuous elongate bead of material that can form a polymeric microstructure according to embodiments;

[0026] FIG. 7B is a schematic view of beads of liquid with a contact angle Q that remains fixed at an equilibrium value while the contact lines are free to move; [0027] FIG. 7C is a schematic view of beads of liquid with a contact angle that depends on the contact line speed, but reduces to an equilibrium value at zero speed, and beads with contact lines that are arrested in a parallel state while the contact angle is free to change

[0028] FIG. 8A is a scanning electron microscope (SEM) photograph of a top view of elongate polymeric micro structures on a glass substrate;

[0029] FIG. 8B is a scanning electron microscope (SEM) photograph of a cross-sectional view of elongate polymeric microstructures on a glass substrate;

[0030] FIG. 8C is a scanning electron microscope (SEM) photograph of an enlarged cross- sectional view of elongate polymeric microstructures on a glass substrate;

[0031] FIG. 9A shows an optical image of lenticular features created on a 20.3 cm x 27.9 cm IRIS glass substrate;

[0032] FIG. 9B shows an optical image of lenticular features created on a 20.3 cm x 27.9 cm IRIS glass substrate;

[0033] FIG. 10A shows an optical image of lenticular features created on a 20.3 cm x 27.9 cm IRIS glass substrate;

[0034] FIG. 10B shows an optical image of lenticular features created on a 20.3 cm x 27.9 cm IRIS glass substrate;

[0035] FIG. 11 A shows results of light confinement measurements carried out on a 280 mm x 215 mm bare glass sample and a laminated lenticular lens structure on a 280 mm x 215 mm glass sample;

[0036] FIG. 11B shows results of light confinement measurements conducted on a continuously dispensed microstructures on a 280 mm x 215 mm glass sample;

[0037] FIG. 11C shows results of light confinement measurements carried out on a continuously dispensed microstructures on a 280 mm x 215 mm glass sample;

[0038] FIG. 12A shows the light confinement in a plot of normalized optical brightness of bare glass LGP, glass LGP with laminated lenticular film, and glass LGP with dispensed microstructures at a distance 250 mm from the input edge as a function of position (mm);

[0039] FIG. 12B shows the light confinement in a plot of normalized optical brightness of a glass LGP with dispensed microstructures at 250 mm distance from input edge as a function of position (mm) and a resulting Lorentzian fitting curve;

[0040] FIG. 13 shows the light confinement in a plot of normalized optical brightness of a glass LGP with a laminated lenticular film, and glass LGPs with dispensed microstructures at a distance of 250 mm from the input edge as a function of position (mm); [0041] FIG. 14 is a block diagram of an embodiment of an apparatus 200 that can be used to continuously dispense and cure a curable liquid in accordance with embodiments of the disclosure;

[0042] FIG. 15 is a graph showing color shift (delta chromaticity y value over 320 mm) for coated samples made using various material having a thickness greater than 10 pm thickness;

[0043] FIG. 16 is a depiction of steps that can be used to screen print an elongate polymeric micro structure according to embodiments of the disclosure;

[0044] FIG. 17 is a graph representing steady shear sweep (shear viscosity versus shear rate) for screen printed inks containing Texanol solvent;

[0045] FIG. 18 is a graph of representing steady shear sweep (shear viscosity versus shear rate) for screen print inks containing diethyleneglycolmonomethyl (Dowanol DPM™ solvent);

[0046] FIG. 19 s a graph showing shear viscosity versus time for two screen-printed inks containing Texanol™ solvent;

[0047] FIG. 20 is a graph of shear viscosity versus time for three screen-printed inks containing Dowanol DPM™ solvent;

[0048] FIG. 21 shows results of light confinement measurements carried out on a glass LGP with screen printed microstructures made according to one or more embodiments of the disclosure compared with a bare glass LGP and a glass LGP with a laminated lenticular film;

[0049] FIG. 22 is a graph illustrating light confinement plotting normalized optical brightness of a glass LGP with screen printed microstructures at 250 mm distance from an input edge as a function of position (mm) and a Lorentzian fitting curve;

[0050] FIG. 23 A is an SEM photograph of a top view of screen-printed elongate polymeric microstructures;

[0051] FIG. 23B is an SEM photograph of a side view of the screen-printed elongate polymeric microstructures shown in FIG. 23 A;

[0052] FIG. 23 C is an SEM photograph of an enlarged side view of a single one of the screen-printed elongate polymeric microstructures shown in FIG. 23B

[0053] FIG. 24A is an SEM photograph of a top view of screen-printed elongate polymeric microstructures;

[0054] FIG. 24B is an SEM photograph of a side view of the screen-printed elongate polymeric microstructures shown in FIG. 24A; [0055] FIG. 24C is an SEM photograph of a an enlarged side view of a single one of the screen-printed elongate polymeric microstructures shown in FIG. 24B;

[0056] FIG. 25A is an SEM photograph of a side view of screen-printed elongate polymeric microstructures;

[0057] FIG. 25B is an SEM photograph of a side view of screen-printed elongate polymeric microstructure;

[0058] FIG. 26 is a top plan view of a light guide plate with elongate polymeric

micro structures on a glass substrate;

[0059] FIG. 27 shows a cross-sectional view of an elongate polymeric microstructure 70 taken along line 27-27 of FIG. 26;

[0060] FIG. 28 is a schematic for describing the definitions of the local dimming index (LDI) and the straightness;

[0061] FIG. 29 is a graph which shows light leakage (percentage of total light coupled into the LGP) as a function of surface slope angle of the lenticular waviness along the lenticular direction based on modelling;

[0062] FIG. 30 is a graph which shows the LDI (for 150 mm dimming width) at 450 mm distance from an input edge as a function of surface slope angle of the lenticular waviness along the lenticular direction based on modelling; and

[0063] FIG. 31 is a graph which shows the straightness at 450 mm distance from an input edge as a function of surface slope angle of the lenticular waviness along the lenticular direction based on modelling.

DETAILED DESCRIPTION

[0064] Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. However, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0065] An aspect of the disclosure pertains to light guide plates comprising a glass substrate including an edge surface and two major surfaces; and a plurality of elongate polymeric multilayer micro structures on at least one of the major surfaces, each elongate multilayer microstructure having a maximum height H and a width W measured at one-half of the maximum height (H/2) and further comprising an aspect ratio W/H in a range of from about 0.1 to about 10, from about 2 to about 9, from about 2 to about 8, from about 2 to about 7 or from about 2.5 and to about 6. In some embodiments, each elongate polymeric multilayer microstructure comprises at least two layers, at least three layers, at least four layers, at least five layers, at least six layers, at least seven layers, at least eight layers, at least nine layers or at least ten layers. In some embodiments, each of the layers is at least partially an individually cured layer. In one or more embodiments, the height H of each of the plurality of elongate polymeric microstructures does not exceed 100 micrometers (pm), for example in a range of from about 5 pm to about lOOpm. In some embodiments, there is a first spacing S between two adjacent elongate polymeric microstructures in a first direction in a range of from about 0.0l*W to about 4*W, or from about 0.0l*W to about 3*W, or from about 0.0l*W to about 2.5*W, or from about 0.01 *W to about 2*W, or from about 0.01 *W to about l.5*W, or from about 0.01 *W to about l*W.

[0066] In some embodiments, the first spacing S is the same between all adjacent elongate polymeric microstructures of the plurality of elongate polymeric microstructures. In alternate embodiments, the first spacing S between one pair of two adjacent elongate polymeric micro structures different that the first spacing between another pair of adjacent elongate polymeric microstructures. In one or more embodiments, there is a second spacing S2 between two adjacent elongate polymeric microstructures in a second direction orthogonal to the first direction in a range of from about 10 pm to about 5000 pm. In some

embodiments, the second spacing S2 is the same between all adjacent elongate polymeric microstructures of the plurality of elongate polymeric microstructures. In alternate embodiments, the second spacing S2 between a one pair of two adjacent elongate polymeric microstructures different that the second spacing S2 between another pair of adjacent elongate polymeric micro structures.

[0067] In one or more embodiments, at least one of the plurality of elongate polymeric multilayer microstructures further comprises a length L, and wherein another one of the plurality of elongate polymeric multilayer microstructures has a length L2 different from L.

[0068] In some embodiments, there is a slope angle of an end surface of at least one of the plurality of microstructures that is less than about 15 degrees.

[0069] In one or more embodiments, there is a refractive index difference between the substrate and the plurality of microstructures is less than 10%.

[0070] In some embodiments, the glass substrate comprises, on a mol% oxide basis:

50-90 mol% Si0₂,

0-20 mol% AI2O3, 0-20 mol% B2O3, and

0-25 mol% R_xO,

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.

[0071] In some embodiments, a thickness di of the glass substrate ranges from about 0.1 millimeters (mm) to about 3 mm. In one or more embodiments, the polymeric film comprises a UV curable or thermally curable polymer. In some embodiments, the polymeric film is microreplicated, screen printed, inkjet-printed, laser bonded, printed, or grown onto the light emitting surface of the glass substrate.

[0072] One or more embodiments include a light guide plate comprising a glass substrate having an edge surface and a light emitting surface, a multilayer polymeric film comprising a plurality of microstructures disposed on the light emitting surface of the glass substrate, and a combined light attenuation a’ of less than about 5 dB/m for wavelengths ranging from about 420-750 nm.

[0073] Another aspect of the disclosure pertains to a light guide plate comprising a glass substrate including an edge surface and a light emitting surface; and a plurality of elongate polymeric micro structures, each of the plurality of elongate polymeric microstructures comprises a surface slope angle of less than 15 degrees, less than 10 degrees, less than 4 degrees or less than 2 degrees. The surface slope angle is defined by an angle formed between a line parallel to the light emitting surface of the glass substrate and a line extending between a first uppermost surface of the elongate polymeric microstructure at maximum height Hi and a second uppermost surface of the elongate polymeric microstructure at minimum height ¾.

[0074] In some embodiments, the elongate polymeric microstructures comprise multiple layers, and are thus elongate polymeric multilayer microstructures. In specific embodiments, elongate polymeric multilayer microstructures have the surface slope angle of less than 15 degrees, less than 10 degrees, less than 4 degrees or less than 2 degrees and each elongate polymeric multilayer microstructure has a height Hl and a width W defining an aspect ratio, wherein the aspect ratio is represented as W/H and is in a range of from about 0.1 to about 10, from about 2 to about 9, from about 2 to about 8, from about 2 to about 7 or from about 2.5 and to about 6.

[0075] Further embodiments of the disclosure include methods of manufacturing light guide plates comprising a multilayer polymeric film comprising a plurality of microstructures disposed on a light emitting surface of the glass substrate. Additional embodiments of the disclosure relate to light guide assemblies comprising a light guide plate including a glass substrate having an edge surface and a light emitting surface, a multilayer polymeric film comprising a plurality of elongate microstructures disposed on a light emitting surface of the glass substrate, and at least one light source optically coupled to the edge surface of the glass substrate.

[0076] Various devices comprising such light guides are also disclosed herein, such as display, lighting, and electronic devices, e.g., televisions, computers, phones, tablets, and other display panels, luminaires, solid-state lighting, billboards, and other architectural elements, to name a few.

[0077] Various embodiments of the disclosure will now be discussed with reference to the figures, which illustrate exemplary embodiments of microstructure arrays and 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, these embodiments being interchangeable with one another within the context of the disclosure.

[0078] An exemplary LCD display device 10 is shown in FIG. 1 comprising an LCD display panel 12 formed from a first substrate 14 and a second substrate 16 joined by an adhesive material 18 positioned between and around a peripheral edge portion of the first and second substrates. First and second substrates 14, 16 and adhesive material 18 form a gap 20 therebetween containing liquid crystal material. Spacers (not shown) may also be used at various locations within the gap to maintain consistent spacing of the gap. First substrate 14 may include color filter material. Accordingly, first substrate 14 may be referred to as the color filter substrate. On the other hand, second substrate 16 includes thin film transistors (TFTs) for controlling the polarization state of the liquid crystal material, and may be referred to as the backplane. LCD panel 12 may further include one or more polarizing filters 22 positioned on a surface thereof.

[0079] LCD display device 10 further comprises BLU 24 arranged to illuminate LCD panel 12 from behind, i.e., from the backplane side of the LCD panel. In some embodiments, the BLU may be spaced apart from the LCD panel, although in further embodiments, the BLU may be in contact with or coupled to the LCD panel, such as with a transparent adhesive.

BLU 24 comprises a glass light guide plate (LGP) 26 formed with a glass substrate 28 as the light guide, glass substrate 28 including a first major surface 30, a second major surface 32, and a plurality of edge surfaces extending between the first and second major surfaces. In embodiments, glass substrate 28 may be a parallelogram, for example a square or rectangle comprising four edge surfaces 34a, 34b, 34c and 34d as shown in FIG. 2 extending between the first and second major surfaces defining an X-Y plane of the glass substrate 28, as shown by the X-Y-Z coordinates. For example, edge surface 34a may be opposite edge surface 34c, and edge surface 34b may be positioned opposite edge surface 34d. Edge surface 34a may be parallel with opposing edge surface 34c, and edge surface 34b may be parallel with opposing edge surface 34d. Edge surfaces 34a and 34c may be orthogonal to edge surfaces 34b and 34d. The edge surfaces 34a - 34d may be planar and orthogonal to, or substantially orthogonal (e.g., 90 +/- 1 degree, for example 90 +/- 0.1 degree) to major surfaces 30, 32, although in further embodiments, the edge surfaces may include chamfers, for example a planar center portion orthogonal to, or substantially orthogonal to major surfaces 30, 32 and joined to the first and second major surfaces by two adjacent angled surface portions.

[0080] First and/or second major surfaces 30, 32 may include an average roughness (Ra) in a range from about 0.1 nanometer (nm) to about 0.6 nm, for example less than about 0.6 nm, less than about 0.5 nm, less than about 0.4 nm, less than about 0.3 nm, less than about 0.2 nm, or less than about 0.1 nm. An average roughness (Ra) of the edge surfaces may be equal to or less than about 0.05 micrometers (pm), for example in a range from about 0.005 micrometers to about 0.05 micrometers.

[0081] The foregoing level of major surface roughness can be achieved, for example, by using a fusion draw process or a float glass process followed by polishing. Surface roughness may be measured, for example, by atomic force microscopy, white light interferometry with a commercial system such as those manufactured by Zygo, or by laser confocal microscopy with a commercial system such as those provided by Keyence. The scattering from the surface may be measured by preparing a range of samples identical except for the surface roughness, and then measuring the internal transmittance of each. The difference in internal transmission between samples is attributable to the scattering loss induced by the roughened surface. Edge roughness can be achieved by grinding and/or polishing.

[0082] Glass substrate 28 further comprises a maximum glass substrate thickness t in a direction orthogonal to first major surface 30 and second major surface 32. In some embodiments, glass substrate thickness t may be equal to or less than about 3 mm, for example equal to or less than about 2 mm, or equal to or less than about 1 mm, although in further embodiments, glass substrate thickness t may be in a range from about 0.1 mm to about 3 mm, for example in a range from about 0.1 mm to about 2.5 mm, in a range from about 0.3 mm to about 2.1 mm, in a range from about 0.5 mm to about 2.1 mm, in a range from about 0.6 mm to about 2.1 mm, or in a range from about 0.6 mm to about 1.1 mm, including all ranges and subranges therebetween.

[0083] In various embodiments, the glass composition of glass substrate 28 may comprise between 60-80 mol% S1O2, between 0-20 mol% AI2O3_, and between 0-15 mol% B2O3, and comprise less than about 50 ppm iron (Fe) concentration. In some embodiments, there may be less than 25 ppm Fe, or in some embodiments the Fe concentration may be about 20 ppm or less. In various embodiments, the thermal conductivity of the glass substrate 28 may be greater than 0.5 W/m/K, for example in a range from about 0.5 to about 0.8 W/m/K. In additional embodiments, glass substrate 28 may be formed by a polished float glass, a fusion draw process, a slot draw process, a redraw process, or another suitable glass substrate forming process.

[0084] In some embodiments, glass substrate 28 comprises S1O2 in a range from about 65.79 mol % to about 78.17 mol%, AI2O3 in a range from about 2.94 mol% to about 12.12 mol%, B2O3 in a range from 0 mol% to about 11.16 mol%, L12O in a range from 0 mol% to about 2.06 mol%, Na₂0 in a range from about 3.52 mol% to about 13.25 mol%, K2O in a range from 0 mol% to about 4.83 mol%, ZnO in a range from 0 mol% to about 3.01 mol%, MgO in a range from about 0 mol% to about 8.72 mol%, CaO in a range from about 0 mol% to about 4.24 mol%, SrO in a range from about 0 mol% to about 6.17 mol%, BaO in a range from about 0 mol% to about 4.3 mol%, and SnO in a range from about 0.07 mol% to about 0.11 mol%. In some embodiments, the glass substrate can exhibit a color shift less than about 0.008, for example less than about 0.005. In some embodiments, the glass substrate comprises an R_xO/AhCb in a range from about 0.95 to about 3.23, wherein R is any one or more of Li, Na, K, Rb and Cs, and x is 2. In some embodiments, the glass substrate comprises an R_xO/ALCb 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 some embodiments, the glass substrate comprises an R_xO - AI2O3 - MgO in a range from about -4.25 to about 4.0, wherein R is any one or more of Li, Na, K, Rb and Cs, and x is 2.

[0085] In further embodiments, the glass substrate may comprise ZnO in a range from about 0.1 mol % to about 3.0 mol %, T1O2 in a range from about 0.1 mol % to about 1.0 mol %_. V2O3 in a range from about 0.1 mol % to about 1.0 mol %_. Nb O in a range from about 0.1 mol % to about 1.0 mol %_. MnO in a range from about 0.1 mol % to about 1.0 mol %, Zr0₂ in a range from about 0.1 mol % to about 1.0 mol %_. AS2O3 in a range from about 0.1 mol % to about 1.0 mol %, SnO in a range from about 0.1 mol % to about 1.0 mol %, M0O3 in a range from about 0.1 mol % to about 1.0 mol %, Sb Ch in a range from about 0.1 mol % to about 1.0 mol %, or CeCh in a range from about 0.1 mol % to about 1.0 mol %. In additional embodiments, the glass substrate may comprise between 0.1 mol% to no more than about 3.0 mol% of one of or a combination of any of ZnO, T1O2, V2O3, Nb O , MnO, ZrCh, AS2O3, SnC , M0O3, Sb₂0₃, and CeC

[0086] It should be understood, however, that embodiments described herein are not limited by glass composition, and the foregoing compositional embodiments are not limiting in that regard.

[0087] In accordance with embodiments described herein, BLU 24 further comprises an array of light emitting diodes (LEDs) 36 arranged along at least one edge surface (a light injection edge surface) of glass substrate 28, for example edge surface 34a. It should be noted that while the embodiment depicted in FIG. 1 shows a single edge surface 34a injected with light, the claimed subject matter should not be so limited, as any one or several of the edges of an exemplary glass substrate 28 can be injected with light. For example, in some embodiments, the edge surface 34a and its opposing edge surface 34c can both be injected with light.

Additional embodiments may inject light at edge surface 34b and its opposing edge surface 34d rather than, or in addition to, the edge surface 34a and/or its opposing edge surface 34c. The light injection surface(s) may be configured to scatter light within an angle less than 12.8 degrees full width half maximum (FWHM) in transmission.

[0088] In some embodiments, LEDs 36 may be located a distance d from the light injection edge surface, e.g., edge surface 34a, of less than about 0.5 mm. According to one or more embodiments, LEDs 36 may comprise a thickness or height that is less than or equal to thickness t of glass substrate 28 to provide efficient light coupling into the glass substrate.

[0089] Light emitted by the array of LEDs is injected through the at least one edge surface 34a and guided through the glass substrate by total internal reflection, and extracted to illuminate LCD panel 12, for example by extraction features on one or both major surfaces 30, 32 of glass substrate 28. Such extraction features disrupt the total internal reflection, and cause light propagating within glass substrate 28 to be directed out of the glass substrate through one or both of major surfaces 30, 32. Accordingly, BLU 24 may further include a reflector plate 38 positioned behind glass substrate 28, opposite LCD panel 12, to redirect light extracted from the back side of the glass substrate, e.g., major surface 32, to a forward direction (toward LCD panel 12). Suitable light extraction features can include a roughed surface on the glass substrate, produced either by roughening a surface of the glass substrate directly, or by coating the sheet with a suitable coating, for example a diffusion film. Light extraction features in some embodiments can be obtained, for example, by printing reflective discrete regions (e.g., white dots) with a suitable ink, such as a UV-curable ink and drying and/or curing the ink. In some embodiments, combinations of the foregoing extraction features may be used, or other extraction features as are known in the art may be employed.

[0090] BLU may further include one or more films or coatings (not shown) deposited on a major surface of the glass substrate, for example a quantum dot film, a diffusing film, and reflective polarizing film, or a combination thereof.

[0091] Local dimming, e.g., one dimensional (1D) dimming, can be accomplished by turning on selected LEDs 36 illuminating a first region along the at least one edge surface 34a of glass substrate 28, while other LEDs 36 illuminating adjacent regions are turned off.

Conversely, 1D local dimming can be accomplished by turning off selected LEDs illuminating the first region, while LEDs illuminating adjacent regions are turned on.

[0092] FIG. 2 shows a portion of an exemplary LGP 26 comprising a first sub-array 40a of LEDs arranged along edge surface 34a of glass substrate 28, a second sub-array 40b of LEDs arranged along edge surface 34a of glass substrate 28, and a third sub-array 40c of LEDs 36 arranged along edge surface 34a of glass substrate 28. Three distinct regions of the glass substrate illuminated by the three sub-arrays are labeled A, B and C, wherein the A region is the middle region, and the B and C regions are adjacent the A region. Regions A, B and C are illuminated by LED sub-arrays 40a, 40b and 40c, respectively. With the LEDs of sub-array 40a in the "on" state and all other LEDs of other sub-arrays, for example the sub-arrays 40b and 40c, in the "off¹ state, a local dimming index LDI can be defined as 1 - (average luminosity of the B, C regions)/(luminosity of the A region). A fuller explanation of determining LDI can be found, for example, in "Local Dimming Design and Optimization for Edge-Type LED Backlight Unit": Jung, et al, SID 2011 Digest, 2011, pp. 1430 - 1432, the content of which is incorporated herein by reference in its entirety.

[0093] It should be noted that the number of LEDs within any one array or sub-array, or even the number of sub-arrays, is at least a function of the size of the display device, and that the number of LEDs depicted in FIG. 2 are for illustration only and not intended as limiting. Accordingly, each sub-array can include a single LED, or more than one LED, or a plurality of sub-arrays can be provided in a number as necessary to illuminate a particular LCD panel, such as three sub-arrays, four sub-arrays, five sub-arrays, and so forth. For example, a typical 1D local dimming-capable 55" (139.7 cm) LCD TV may have 8 to 12 zones. The zone width is typically in a range from about 100 mm to about 150 mm, although in some embodiments the zone width can be smaller. The zone length is about the same as a length of glass substrate 28.

[0094] Referring now to FIGs. 3 A - 3E, which show various embodiments of light guide plates, a light guide plate 26 comprises glass substrate 28 having a glass substrate thickness t and a plurality of polymeric microstructures 70. In specific embodiments, the polymeric microstructures 70 are polymeric multilayer microstructures 70. As shown in FIG. 3 A, the plurality of polymeric multilayer microstructures 70 provides a plurality of rectangular or square channels 60 positioned on a surface of the glass substrate, for example first major surface 30, although in further embodiments, the plurality of channels may be formed in second major surface 32, or both first major surface 30 and second major surface 32. In some embodiments, light extraction features may be formed in one or both of the first major surface 30 and the second major surface 32. In some embodiments, each channel of the plurality of channels 60 is substantially parallel to an adjacent channel of the plurality of channels 60. Each polymeric multilayer microstructure 70 comprises a maximum height H and a width W defined at H/2 (one-half the height H of the polymeric multilayer

micro structure 70), which is indicated by the line H/2 in FIGS. 3A-E. Each polymeric multilayer microstructure 70 has a width W, and adjacent polymeric multilayer

microstructures 70 are separated by a distance S at H/2 (at one-half the maximum height H of the polymeric multilayer microstructure 70). The light guide plate thickness T is defined by the glass substrate thickness t and the maximum height H of the polymeric multilayer microstructures 70. Adjacent polymeric multilayer microstructures 70 define channels 60 which separate the adjacent polymeric multilayer microstructures by the distance S.

[0095] One or more polymeric multilayer microstructures 70 has a non-zero maximum height H. For example, H can range from about 5 pm to about 300 pm, such as from about 10 pm to about 250 pm, from about 15 pm to about 200 pm, from about 20 pm to about 150 pm, from about 30 pm to about 100 pm, from about 20 pm to about 90 pm, including all ranges and subranges there between, although other heights are also contemplated depending on the cross-sectional shape of the polymeric multilayer microstructures 70. In some embodiments, width W can range from about 50 pm to about 1 mm, such as from about 50 pm to about 500 pm, from about 100 pm to about 400 pm, from about 100 pm to about 300 pm, from about 100 mih to about 250 mih, from about 100 mih to about 200 mih, from about 100 mih to about 190 mih, from about 100 mih to about 180 mih, from about 100 mih to about 175 mih, or from about 100 mih to about 150 mih including all ranges and subranges therebetween, although other widths are also contemplated the cross-sectional shape of the polymeric multilayer microstructures 70. The polymeric multilayer microstructures 70 may have a cross-sectional dimension W at H/2 (at one-half the maximum depth H of each channel).

[0096] The polymeric multilayer microstructures 70 may be periodic, with a period P = W+S, although in further embodiments, the polymeric multilayer microstructures 70 may be non periodic. The polymeric multilayer microstructures 70 may be of a variety of cross-sectional shapes. For example, in the embodiment of FIG. 3A, polymeric multilayer microstructures 70 are of a rectangular shape in a cross section perpendicular to a longitudinal axis of each polymeric multilayer microstructure 70 in the X-Y plane. In the embodiment of FIG. 3B, each polymeric multilayer micro structure 70 is of a curved cross-sectional shape, for example, so that each channel 60 has a circular cross-section, such as semicircular, while in the embodiment of FIG. 3C, each polymeric multilayer microstructure 70 comprises a trapezoidal cross-sectional shape. In FIG. 3D, each polymeric multilayer microstructure 70 comprises a semicircular lenticular lens positioned on glass substrate 28. In some

embodiments, a polymeric platform (not shown) may be disposed between the glass substrate 28 and each polymeric multilayer micro structure 70. However, the cross-sectional shapes of FIGS. 3 A - 3D are not limiting, and the polymeric multilayer microstructures 70 may comprise other shapes, or combination of cross-sectional shapes such as prisms or rounded prisms. For example, in the embodiment shown in FIG. 3E, each polymeric multilayer microstructure 70 comprises a prism cross-sectional shape, and the prism can have a prism angle Q ranging from about 60° to about 120°, such as from about 70° to about 110°, from about 80° to about 100°, or about 90°, including all ranges and subranges therebetween. In FIG. 3E, the polymeric multilayer microstructures 70 are disposed on a polymeric platform 72 having a polymeric platform thickness t2, which is disposed on the glass substrate 28. The light guide plate thickness T in FIG. 3 is the sum of the glass substrate thickness t, the polymeric platform thickness t2 and the height H of the polymeric multilayer microstructures 70. Other suitable cross-sectional shapes of polymeric multilayer microstructures 70 include semi-circular, semi-elliptical, parabolic, or other similar rounded shapes. Furthermore, while FIGS. 3 A-E illustrate regular (or periodic) arrays, it is also possible to use an irregular (or non-periodic) array. For example, FIG. 3F is an SEM image of a microstructured surface comprising a non-periodic array of polymeric multilayer prisms.

[0097] In some embodiments, a ratio W/H of each polymeric multilayer microstructure 70 of the plurality of polymeric multilayer micro structures 70 is in a range from about 0.1 to about 10, for example from about 2 to 9, from about 2 to about 8, from about 2 to about 7, from about 2.5 to about 6 or from about 2.5 to about 5, including all ranges and subranges therebetween. In some embodiments, when W/H is greater than about 10, the polymeric multilayer micro structures 70 can become ineffective for 1D local dimming. In some embodiments, when W/H is less than about 0.1, the polymeric multilayer microstructures 70 can be difficult to make.

[0098] As used herein, the term "microstructures," "microstructured," and variations thereof is intended to refer to surface relief features of a cured film formed from a resin composition having at least one dimension (e.g., height, width, length, etc.) that is less than about 500 pm, such as less than about 400 pm, less than about 300 pm, less than about 200 pm, less than about 100 pm, less than about 50 pm, or even less, e.g., ranging from about 10 pm to about 500 pm, including all ranges and subranges therebetween. In some embodiments, cured films form polymeric microstructures, which may, in certain embodiments, have regular or irregular shapes, which can be identical or different within a given array. While FIGS. 3A-E generally illustrate polymeric multilayer microstructures 70 of the same size and shape, which are evenly spaced apart at substantially the same pitch (e.g., periodicity), it is to be understood that not all polymeric multilayer microstructures within a given array must have the same size and/or shape and/or spacing. Combinations of polymeric multilayer

micro structure shapes and/or sizes may be used, and such combinations may be arranged in a periodic or non-periodic fashion.

[0099] Moreover, the size and/or shape of the polymeric multilayer microstructures can be varied depending on the desired light output and/or optical functionality of the LGP. For example, different polymeric multilayer micro structure 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 polymeric multilayer 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%. The microstructure size and/or shape and/or spacing may be varied to achieve different LDI values. Different polymeric multilayer microstructures 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.

[00100] Each of the polymeric micro structures shown in FIGs. 3 A-F may be formed on a glass substrate to provide a light guide plate as described with respect to FIG. 4. Thus, each of the structures described with respect to FIGs. 3 A-F may function as lenticular structures, lenticular lenses or lenticular features which are effective to direct light emanating through a major surface of a light guide plate. Thus, the term "lenticular" is not limited to a particular shape or cross-sectional shape and can include elongate micro structures having a cross- sectional shape that is convex or concave curved such as those shown in FIGSs. 3B and 3D, square rectangular or square as shown in FIG. 3 A, trapezoidal as shown in FIG. 3C, or triangular as shown in FIG. 3E.

[00101] Referring now to FIG. 4, a light guide plate 26 is shown including at least one light source 40 that can be optically coupled to an edge surface 29 of the glass substrate 28, e.g., positioned adjacent to the edge surface 29. 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.

[00102] Light injected into the LGP from a light source 40 may propagate along a length L of the LGP as indicated by arrow 161 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:

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, «₂ is the refractive index of a second material, Q i is the angle of the light incident at the interface relative to a normal to the interface (incident angle), and Q _r is the angle of refraction of the refracted light relative to the normal. When the angle of refraction (Q _r) is 90°, e.g., sin(9 _r) = 1, Snell's law can be expressed as:

[00105] The incident angle Q i under these conditions may also be referred to as the critical angle Q _c. Light having an incident angle greater than the critical angle (Q i > Q _c) will be totally internally reflected within the first material, whereas light with an incident angle equal to or less than the critical angle (Q i < Q _c) will be mostly transmitted by the first material.

[00106] In the case of an exemplary interface between air ( m=\ ) and glass («2= 1.5), the critical angle (Q _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.

[00107] In some embodiments, a polymeric platform 72 may be disposed on a major surface of the glass substrate 28, such as light emitting surface 160, opposite second major surface 170. The array of microstructures 70 may, along with other optical films (e.g., a reflector film and one or more diffuser films, not shown) disposed on surfaces 160 and 170 of the LGP, direct the transmission of light in a forward direction (e.g., toward a user), as indicated by the dashed arrows 162. In some embodiments, light source 40 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 arrow 161 in FIG. 4), 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 (1D) local dimming of at least a portion of the LGP in a relatively efficient manner.

[00108] According to one or more embodiments, light guide plates are manufactured by applying a radiation curable material, for, example, a resin composition that allows patterning of elongate polymeric microstructures 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. As used herein, "radiation curable" refers to a material that utilizes light energy provided by ultraviolet, infra read, or visible light or thermal energy to initiate a curing reaction. In some embodiments, light emitted by a radiation source reacts with a photoinitiator in a resin composition to form a polymeric microstructure. Examples of radiation curable materials include acrylates (e.g., methacrylates) and epoxies. In one or more embodiments, a method is provided that allows patterning to provide a plurality of multilayer microstructures, at least one microstructure having a maximum height H, a width W measured at one-half of the maximum height (El/2) and a ratio W/H in a range from about 0.1 to about 10. The ratio of W/H may also be referred to as an aspect ratio of the elongate polymeric micro structure.

[00109] Referring to now FIG. 5, one or more embodiments provide elongate polymeric micro structures that are polymeric multilayer microstructures 70 disposed on a glass substrate 28. FIG. 5 shows an enlarged cross-sectional view of a single polymeric multilayer microstructure 70 on a glass substrate 28 in accordance with an embodiment of the disclosure. While the embodiment shown in FIG. 5 has a semi-circular cross-section similar to polymeric multilayer microstructures 70 shown in FIG. 3D, it will be understood that the polymeric multilayer micro structures can be any cross-sectional shape suitable for use with a light guide plate, such as those shown in FIGS. 3A-3E. In FIG. 5, the polymeric multilayer microstructure 70 comprises a first polymeric layer 70a disposed on the glass substrate 28, a second polymeric layer 70b disposed on the first polymeric layer, 70a and a third polymeric layer 70c disposed on the second polymeric layer 70b. The number of individual polymeric layers "n" is not limited to the three layers 70a, 70b and 70c shown in FIG. 5. In one or more embodiments, the number of individual layers "n" can be in a range of from 2 to 25, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20. As will be described further below, embodiments of the disclosure provide a light guide plate comprising a glass substrate comprising a plurality of polymeric multilayer microstructures, wherein the number of layers "n" ranges from 2 to 20, or from 2 to 15, or from 2 to 10 or from 2 to 5. In some embodiments, each of the individual layers is partially cured before the next layer is deposited. In one or more embodiments, "partially cured" includes curing in a range of 20%- 80%, 20%-70%, 20%-60%, 20%-50%,20%-40%, 40%-60%, 40%-80%, 50%-60%, 50%- 80%, or 60%-80%. [00110] Referring now to FIG. 6A, an exemplary, non-limiting cross-section of an embodiment of a polymeric multilayer microstructure is schematically shown which is in this case a section of a circle where W, H and Q are the width, height and the contact angle of the shape, respectively. FIG. 6B is a graph of contact angle as function of the aspect ratio, W/H (width/height). The optical design of the lenticular features requires low aspect ratio, at least W/H < 10. In general, according to one or more embodiments, the lower the value of W/H, the greater is the effect of confinement of light by wave-guiding. According to some embodiments, the contact angle, Q, in turn, is > 45° corresponding to W/H < 5. However, creating such structure by printing with a precursor liquid composition can be challenging.

For such a high contact angle value, a printed liquid line becomes unstable due to Rayleigh- Taylor instability and breaks down into drops as depicted in FIGS. 7B And 7C.

[00111] FIG. 7A shows a stable, undisturbed continuous elongate bead of material that can form a polymeric microstructure 70. FIG. 7B shows a perturbed bead of liquid with a contact angle Q that remains fixed at an equilibrium value while the contact lines are free to move. FIG. 7C shows beads of liquid with a contact angle that depends on speed of deposition, but reduces to an equilibrium value at zero speed, and beads with contact lines that are arrested in a parallel state while the contact angle is free to change. For further details of liquid bead stability on a solid surface, see Schiaffaino and Sonin, Formation and stability of liquid and molten beads on a solid surface, J. Fluid Mech. Vol. 343, pp. 95-110, (1997). Instabilities which proceed faster than the solidification mechanism will cause bead non-uniformity.

[00112] It was determined that there are two ways to mitigate bead instability. One approach involves roughening the glass surface of the substrate used to form a light guide plate so that the contact line remains pinned. However, this requires additional processing to obtain a roughened glass surface. It was determined that bead instability could be avoided by at least partially curing the deposited curable material to increase viscosity of the material and prevent the evolution of instability during deposition. By sequentially depositing and at least partially curing the deposited individual layers, followed by depositing and curing additional individual layers in the same manner, it was discovered that a plurality of multilayer microstructures could be formed where at least one microstructure has a maximum height H and a width W measured at one-half of the maximum height (H/2) and comprising a ratio W/H in a range from about 0.1 to about 10, for example from about 2 to 9, from about 2 to about 8, from about 2 to about 7, from about 2.5 to about 6 or from about 2.5 to about 5. [00113] One or more embodiments of the disclosure provide methods comprising continuously dispensing a curable liquid that is at least partially cured by radiation (e.g., ultraviolet (UV) illumination, infrared (IR) or thermal energy) nearly immediately or instantaneously after the liquid has been deposited. In one or more embodiments, "nearly immediately after deposition" and "instantaneously after deposition" means that the curable liquid is cured less than 30 seconds, less than 20 seconds, less than 10 seconds, less than 5 second, less than 4 seconds, less than 3 seconds, less than 2 seconds, less than 0.9 seconds, less than 0.8 seconds, less than 0.7 seconds, less than 0.6 seconds, less than 0.5 seconds, less than 0.4 seconds, less than 0.3 seconds, less than 0.2 seconds, or less than 0.1 seconds after deposition of the curable liquid. The time after deposition of the polymer liquid to commence curing will depend on the viscosity of the liquid and stability of the liquid on a glass surface, which can be determined experimentally. However, generally, the degree of curing and the time of curing should be selected to prevent the bead from becoming instable.

[00114] One or more embodiments includes a process of forming elongate polymeric microstructures comprising depositing a curable liquid, for example, an optically clear UV curable ink, and instantaneously at least partially curing the curable liquid after deposition. In some embodiments, a continuous curable liquid dispenser and an instantaneous radiation curing (e.g., UV curing, IR curing or thermal curing) process is used to continuously fabricate elongate polymeric microstructures on a major surface of a glass substrate. In one or more embodiments, continuous formation of elongate polymeric microstructures is provided that involves in situ curing of the dispensed curable liquid, resulting in pinning the contact line of the ink. The "contact line" refers to the line of contact of the curable material being deposited on the glass substrate. In addition, in one or more embodiments, the method can be repeated more than one time to create a microstructure comprised of multiple layers, referred to herein as elongate polymeric multilayer micro structures, thereby creating a desired aspect ratio for 1D dimming.

[00115] In specific embodiments, a commercial continuous liquid dispenser (GPD Max Series PCD3H available from GPD Global, Inc., Grand Junction, Colorado) is used for the fabrication of elongate polymeric microstructures on glass, and to manufacture lenticular patterns in the formation of light guide plates having the desired aspect ratio for 1D dimming.

[00116] According to one or more embodiments, a continuous dispensing process avoids the creation of discrete droplets as the curable liquid ejects from the dispenser. In some embodiments, the apparatus includes a liquid dispenser and an integrated radiation (e.g., UV energy or thermal energy) curing system that immediately follows the dispenser. This allows at least partial curing of the curable liquid (e.g., ink) as soon as it is dispensed on the glass surface, which in turn prevents de-wetting of the ink. In some embodiments, in the absence of the in-situ curing, the ink does not remain as a straight line and leads to a sinusoidal shape or even discrete droplets due to Rayleigh-Plateau instability.

[00117] In one or more embodiments, elongate polymeric microstructures and elongate polymeric multilayer microstructures can be formed using an inkjet printer with a curing head. For example, experiments were conducted to form elongate polymeric microstructures were created on a glass substrate using an inkjet printing process using a commercial piezo inkjet printer with a resolution of 1440 dpi and an optically clear UV curable ink. The inkjet printer had a built-in LED UV curing system that cured the UV ink in every pass. The in situ curing after each pass helped to "pin" the droplet to the surface. According to some embodiments in a first step, an image file of 150 microns wide with a 150 micron gap micro structure lines were created by using an Adobe® illustrator file and converting the file to a postscript file. In a second step, a clean glass substrate having dimension of 8.5 inches xl 1 inches was used as the substrate for printing. An optional silane layer was used to control the spreading of the inkjet drops on the glass surface. In a third step, inkjet printing of the optically clear UV ink was carried out on a layer by layer basis with curing performed after each layer creating elongate multilayer microstructures with various aspect ratios.

Profilometer measurements were taken using a Tencor Pl 1 at a scan speed of 50 pm/sec, a sampling rate of lOOHz and a scan length of 8000 pm. The height of the elongate

microstructures increased from 8-10 micron from a single layer to 18 microns for a two layer micro structure. A three layer inkjet printed elongate microstructure provided a height of 56 microns, and a four layer inket printed elongate micro structure provided a height of 68 microns. The width of the elongate microstructures were calculated to be 168 microns from the same profilometer measurements, resulting in an aspect ratio of 3 : 1 for the three layer inkjet printed elongate microstructures and an aspect ratio of 2: 1 for a four layer inkjet printed elongate microstructures. The three layer and four layer elongate produced 1D dimming effects.

[00118] The methods described herein allowed for the formation of lenticular structures with a low W/H ratio by conducting multiple deposition and curing cycles. FIGS. 8A-C are scanning electron microscope (SEM) photographs of top (FIG. 8 A) and cross-sectional views (FIGS. 8B and 8C) of elongate polymeric micro structures on glass. A liquid nitrogen freeze fracture caused the lenticular structures to delaminate from the glass surface. The structures shown in FIGS. 8A-C were manufactured by four deposition and cure cycles using a GPD Max Series PCD3H dispenser with in situ UV curing. Each lenticular line was made by four consecutive cycles. A close examination of FIG. 8C shows four discrete individual layers, a first layer 70a on the glass substrate, a second layer 70b on the first layer 70a, a third layer 70c on the second layer 70b, and a fourth layer 70d on the third layer 70c. It is clear from FIG. 8 A that the lenticular features are fairly straight without any semblance of instabilities. The cross-section views show each layer of the four layer passes. The curing after each pass locks in the shape of the feature. This allows layer by layer build-up of the features to very low W/H ratio. For example, in this case, width (W) = 170 pm, height (H) = 60 pm and W/H = 2.8, that was much lower than the desired maximum threshold of 5. The details of the curable liquid included, Optical Inks Norland 68TH Low viscosity, Norland 123TKHGA High viscosity and MPOSS nanosilica + 1 wt% 1173 (photoinitiator) + 2 wt% Texanol, MPOSS nanosilica + 1 wt% 1173 (photoinitiator)+ 2 wt% Texanol +2 wt% IPA and MPOSS nanosilica + 1 wt% 1173 (photoinitiator) + 2 wt% IPA. PCD3H dispenser parameters, Auger speed of 74.3rpm and 23mm/sec line dispense speed. After the last layer has been deposited, the polymeric multilayer micro structure may be exposed to radiation to subject the polymeric multilayer micro structure to additional curing to increase the degree of cure. The degree or percentage of cure of a polymeric micro structure can be determined by infrared spectroscopy. In some embodiments, the degree or percentage of cure of a micro structure is determined by correlating the dielectric properties of resins or by the change in refractive index of the microstructure.

[00119] FIG. 9A and 9B show optical images of lenticular features created on an 8 inch x 11 inch (20.3 cm X 27.9 cm) IRIS glass substrate available from Corning, Inc. of Corning, NY using a GPD Max Series PCD3H dispenser with in situ UV curing. Four deposition and cure cycles were utilized. The ink used in this example is Norland Optical 68TH ink with low viscosity of about 20,000 centipoise (cps). The lenticular lines had width of about 150 pm with about 150 pm separation gap between them. From these images, it is clear that well defined lenticular features could be fabricated on large substrates by this approach.

[00120] FIGS. 10A and 10B shows a similar structures to those shown in FIGS. 9 A and 9B, but made with high viscosity Norland Optical 123TKHGA ink having a viscosity of about 500,000 centipoise. Lenticular features were created on an 8 inch x 11 inch IRIS glass substrate available from Corning, Inc. of Corning, NY using a GPD Max Series PCD3H dispenser with in situ UV curing. Four deposition and cure cycles were utilized. In this case, the lenticular line width was about 200 pm and the separation gap was about 109 pm. The structures show in FIGS. 9 A and 9B and 10A and 10B show that it is possible to create structures with ink of varying viscosities in a range of from about 20,000 cps to about 500,000 cps. Commercial inks of varying viscosity from about 20,000 cps to about 500,000 cps show an ability to be dispensed and create the lenticular features.

[00121] A Zygo instrument was used to measure peak-to-valley (PV) heights of the samples shown in FIGS. 9A-B and 10A-B. In FIGS. 9A and 9B, the peak to valley heights were 48 micrometers, and in FIGS. 10A and 1B, the peak to valley heights were 58 micrometers. Dispensing parameters can be optimized to print the required height in one pass or multiple cycles or passes depending on the dispensed materials' viscosity, surface tension and the surface energy of the substrate.

[00122] Light confinement measurements carried out on 280 mm x 215 mm bare glass samples as well as samples made in accordance with FIGS. 9A-B and 10A-B were obtained using a CCD camera. Dispensed samples contained dispensed heights (H) of 50-58 micrometers, dispensed widths (W) 208-220 micrometers with corresponding spacings (S) 120, 92, 80 micrometers. As seen by the images in FIGS. 11 A-C, bare glass samples (FIG.

11 A top) showed no light confinement, a laminated lenticular structure (FIG 11 A, Bottom) showed light confinement (collimated) and all continuously dispensed samples made using a GPD Max Series PCD3H dispenser with in situ UV curing showed similar effect (FIGS. 11B and 11C). In addition, all continuously dispensed samples made using a GPD Max Series PCD3H dispenser with in situ UV curing showed no yellowing (color shift) compared to laminated samples at the output edge.

[00123] FIGS. 12A-B and 13 show the light confinement in a plot of normalized optical brightness as a function of position (mm). All samples show the narrow light distribution similar to the laminated lenticular film. Local dimming index (LDI) >80% for 150 mm dimming width was achieved for all samples at 250 mm distance from the input edge. In particular, WS01448 LDI>87% for 150 mm dimming width was achieved in the sample WS01448 at 250 mm distance from the input edge. In FIGS. 12A and 12B, optical confinement measurement of sample WS0 1448 shows the effect of 1D dimming. Bare glass and laminated lenticular film are shown as controls. Continuously dispensed lenticular structures made using a GPD Max Series PCD3H dispenser with in situ UV curing showed light confinement similar to the laminated film but with an added advantage of reduced optical color shift.

[00124] In FIG. 13, optical confinement measurements of samples WS01443, WS01449, WS01448, WS01453 show the effect of 1D dimming. All continuously dispensed lenticular structures made using a GPD Max Series PCD3H dispenser with in situ UV curing showed the light confinement similar to laminated film but with an added advantage of reduced optical color shift. The LDI > 80% for 150 mm width were achieved for all samples at 250 mm from input edge.

[00125] FIG. 14 is a block diagram of an embodiment of an apparatus 200 that can be used to continuously dispense and cure a curable liquid in accordance with an embodiment of the disclosure. A pump or fluid-dispensing device 216 is used to dispense a curable liquid that is curable by radiation onto a glass substrate moving in the direction of arrow 234. In some embodiments, the pump or fluid-dispensing device 216 can be an auger pump or jetting valve or other pneumatically or electronically-controlled pump or valve, in which the dispensing mechanism is dependent on fluid presented to the inlet of the dispensing device. Other types of pumps or fluid-dispensing mechanisms, such as a time-pressure system could be employed.

[00126] In some embodiments, a reservoir 215 stores a quantity of the curable liquid and supplies it to the pump or fluid-dispensing device 216 via a fluid supply line 223. In one or more embodiments, the reservoir 215 can be a syringe, cartridge or a larger container. In the embodiment shown in FIG. 14, the reservoir 215 is pressured by an external air supply 219, for example, an air compressor, connected by an air supply line 218 regulated by a pressure regulator valve 220 to assist in delivering fluid from the reservoir 215 to the inlet of the pump or fluid-dispensing device 216. In some embodiments, the reservoir can be pressurized by other mechanical apparatus such as a syringe mechanism or hydraulic pressure or electrically, for example, a motor or other electrical motion device.

[00127] In one or more embodiments, a pressure sensor 217 can be utilized to detect the fluid pressure in the fluid supply line 223 between the reservoir 215 and the inlet to the pump or fluid-dispensing device 216. The pressure sensor 217 can be used to regulate the air pressure supplied to the reservoir 215, which, in some embodiments, can be achieved by detecting changes in fluid pressure.

[00128] In some embodiments, a controller 221 receives pressure readings 226 from the pressure sensor 217 either in digital or analog format. In the embodiment shown in FIG. 14, the controller 221 is configured as a feedback controller with the pressure sensor signal 226 as the feedback signal. The output of the controller 221 is a control signal 227 (i.e., a control voltage) applied to a pressure regulator valve 220 in the air pressure line 218 leading from the air supply 219 to the reservoir 215, as shown in FIG. 14. This feedback arrangement

(including the pressure sensor 217, controller 221, and pressure regulator valve 220) effectively regulates the air pressure supplied to the reservoir 215 in response to the fluid pressure measured by the pressure sensor 217 to maintain a predetermined fluid pressure in the fluid supply line, and thereby help maintain a constant input fluid pressure to the pump 216. In turn, this helps to maintain more uniform properties of the fluid pattern dispensed by the pump or fluid-dispensing device 216 (e.g., in terms of first dispense, drop size, line width and volumetric and weight repeatability) at the dispenser tip or nozzle 228. Alternatively, if the reservoir 215 is pressurized by other means, the controller 221 can be used to modulate and regulated the pressure applied to the reservoir 215.

[00129] It should be understood that a variety of different types of controllers could be employed. Also, any of a wide variety of control algorithms can be used by the controller 221. For example, the controller 221 can be configured to regulate the air pressure to maintain a predetermined set point in the measured fluid pressure. This can be done either with, or without a dead band around the desired set point to avoid over-regulation of the air pressure to the reservoir 215. If the measured fluid pressure falls below a predetermined lower limit, the controller 221 adjusts the air supply pressure upward. If the measure fluid pressure rises above a predetermined upper limit, the controller 221 adjusts the air supply pressure downward. A proportional, integral, differential (PID) control algorithm could also be employed to regulate the air supply pressure using the fluid pressure as the feedback signal.

[00130] A radiation source 230, for example, a ultraviolet curing lamp, an infrared curing lamp, or source of thermal energy, is positioned adjacent the dispenser tip or nozzle 228 so that as a substrate moves past the dispenser tip or nozzle 228, curable polymeric fluid is dispensed on a glass substrate and then at least partially cured by radiation (e.g., ultraviolet (UV) illumination or thermal energy) nearly immediately or instantaneously after the liquid has been deposited. In one or more embodiments, "nearly immediately after deposition" and "instantaneously after deposition" means that the curable liquid is cured less than 30 seconds, less than 20 seconds, less than 10 seconds, less than 5 second, less than 4 seconds, less than 3 seconds, less than 2 seconds, less than 0.9 seconds, less than 0.8 seconds, less than 0.7 seconds, less than 0.6 seconds, less than 0.5 seconds, less than 0.4 seconds, less than 0.3 seconds, less than 0.2 seconds, or less than 0.1 seconds after deposition of the curable liquid. A glass substrate could be placed on a suitable apparatus to allow the substrate to move past the dispenser tip or nozzle 228 and then the radiation source 230 at a desired rate so that the radiation source can at least partially cure the curable liquid. The radiation source 230 is in communication with the controller 221, which send control signals via a hard- wired or wireless connection to turn the radiation source on and off and to determine the amount of radiation to be emitted by the radiation source 230 to at least partially cure the curable liquid.

[00131] While a single dispenser tip or nozzle 228 and radiation source 230 are shown in FIG. 14, the embodiment shown is not limiting. For example, the apparatus shown in FIG. 14 can include an array of dispenser tips or nozzles 228 to dispense multiple beads of curable liquid to form a plurality of elongate polymeric microstructures on the glass substrate. For example, the apparatus can include 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or up to 25 dispenser tips or nozzles 228 spaced apart to dispense polymeric fluid on the glass substrate and form a plurality of elongate polymeric microstructures that can be used to form a light guide plate having 1D dimming features. The radiation source 230 can be a 365 nm LED curing source having a width than can cure more than a single elongate polymeric

microstructure, such as a Dymax UV Curing Light Source 38105-2000EC. In some embodiments, an array of radiation sources may be utilized, and the array of radiation sources 230 are in communication with the controller 221. In some embodiments, the degree or percentage of cure of the elongate polymeric microstructures may be monitored in situ. In other words, utilizing a cure monitoring apparatus (e.g. an infrared measurement system) or hardness measurement. In one or more embodiments, after a polymeric multilayer microstructure has been formed by the deposition of multiple layers, the multilayer microstructure is further cured to increase the degree or percentage of curing of the polymeric material.

[00132] In one or more embodiments, the elongate polymeric micro structures are made from a high silicon containing polymer (e.g., greater than 15 wt.%, for example, 15-50 wt.% or 15-30 wt. % , which are highly transparent at visible wavelengths and provides a lenticular lens with lower color shift. In one or more embodiments pertaining to light guide plates, the elongate polymeric micro structures form a lenticular lens having an absorption loss of less than 10 dB/m over the visible wavelength range, or less than 5 dB/m over the visible wavelength range, or less than 2 dB/m over the visible wavelength range. One or more embodiments provide a light guide plate in which there is a refractive index difference between the glass substrate and the elongate polymeric microstructures of less than 10%. In one or more embodiments, the elongate polymeric microstructures have a pencil hardness greater than 4H, for example, greater than 6H (as measured by ASTM D3363 - Standard Test Method for Film Hardness). In some embodiments, the elongate polymeric microstructures exhibit good adhesion, for example, measured using the tape adhesion test of greater than 3 B or greater than 5 B, measured using ASTM D3359 - Standard Test Methods for Rating Adhesion by Tape Test. In one or more embodiments, the elongate polymeric

microstructures do not show color shift with environmental aging, for example, exhibiting an absorption loss less than 10 dB/m over visible wavelength range, or less than 5 dB/m, or less than 2 dB/m based on the color shift.

[00133] In some embodiments of the disclosure, the elongate polymeric microstructures are formed on glass substrates using screen printing and curing individual layers to form layer- by-layer multilayer microstructures. In specific embodiments, elongate polymeric

microstructures screen-printed on a glass substrate are 100-200 pm in length and spaced apart at a distance in a range of 50-100 pm width in between two elongate polymeric

microstructures on the surface of a glass LGP. In one or more embodiments, screen-printing and curing provides the ability to control height, which allows for aspect ratio (defined as width/height of the feature) to change from 3/1 to 10/1. Having taller features enables high aspect ratio (e.g., closer to 2/1) allowing for the tuning of the zone width as low as 20 mm. This minimizes the distance of light propagation on the glass, reduces the color shift introduced by lenticular features and helps in reducing reliability issues due to CTE mismatch between lenticular material and glass.

[00134] In some embodiments the inorganic (glass) substrate with an organic (polymeric) elongate micro structure construction reduces the dispersion, or velocity variation, of different colored light (R,G,B) that occurs along the structure when using different materials for the lenticular structure. This enables the use of injecting white light LEDs. Furthermore, polymeric systems are known to age, or "yellow," particularly with continuous exposure to high light flux. This refractive index variation is a failure mode that is also accompanied with increasing absorption.

[00135] In some embodiments, the radiation curable materials chosen for screen-printing contained both inorganic and organic components. For example, Si together with C, H, O in a polymeric material, where the silicon content was greater than 15 wt.% and carbon content less than 45 wt.% provided good results. Silicon content was increased in an experimental matrix by two methods, either by (1) addition of S1O₂ nanoparticles (~ 20 nm particles 0-30 wt.% dispersed in the matrix); or by (2) addition of organosiloxanes or organosilicate chemistry in the form of polysilsesquioxanes (RSi0_3/2)n or polysilicones (R.2SiO)n.

[00136] Silsesquioxanes are silicate materials, where R is an organic group (or H) bonded to silica through a Si-C bond. Structures of silsesquioxanes have been reported as random, cage and partial cages (Silsesquioxanes, Suzuki et al. Chem. Rev., 1995, 95 (5), pp 1409-1430).

In some embodiments, silsesquioxanes are used which comprise both the cage (T8) and random structures but many other structures are within the scope of the disclosure. In some embodiments, the curable material is polymerized and/or crosslinked using acrylate functionality for the R group with UV photo initiator or thermally polymerized and/or cross linked using IR/heat using R= hydroxyl ( -OH ) functionality (Hybrid Plastics and Gelest).

[00137] In some embodiments, silicone materials can be used to form the elongate polymeric microstructures. Silicones typically have two R groups attached to the silicon through Si-C bonds are also known as elastomers due to their viscoelastic properties.

Silicones can be cured by thermal initiator where high molecular weight linear chains are converted from a highly viscous plastic state into a predominantly elastic state by

crosslinking (suitable materials are available from Dow Corning and Gelest).

[00138] Organosilicon materials tend to have good thermal stability (resist heat and cold, thermal shock), stability to oxidation, moisture, chemicals, and ultraviolet radiation, optical clarity and light transmittance and low color shift with environmental aging due to its thermal and oxidation stability that is required for many advanced photonic and LED applications. FIG. 15 shows color shift (delta chromaticity y value over 320 mm) for coated samples made using various material having a thickness greater than 10 pm thickness. In particular, color shift of bar coated samples on 150 mm x 400 mm glass substrates was measured before and after aging. Aging condition was 90% RH at 60° C for 4 days. The left side Y-axis depicts the color shift delta y over 320 mm distance. Y-axis on the RHS depict the % increase in color shift with aging.

[00139] In one or more embodiments, color shift as measured by using a Spectroradiometer (PR670, Photo Research) was below 0.01/320 mm before and after aging. Polymethyl methacrylate (PMMA) and NEA 121 (UV curable thiophene system (UV cure, Norland opticals)) are used as controls for comparison. The remaining materials shown in FIG. 15 are silicon-containing materials. PMMA shows very low color shift and NEA121 material shows fairly significant yellowing with aging.

[00140] Based upon the color shift data, three kinds of silicon containing polymers were determined to provide acceptable results: polydiphenylsiloxane (silicone, thermal cure 120- 250° C); UV curable polyoctahedral silsesquioxane with silica (MPOSS nano, UV cure, 365 nm UV exposure) and polyphenylsilisesquioxane (thermal cure, 150-420° C cure) . All three silicon containing materials showed low color shift. In addition, silicones offer adhesion, flexibility, and resilience required to seal and protect devices from moisture, dust, and mechanical stress caused by impact and vibration.

[00141] According to one or more embodiments, an array of elongate polymeric

microstructures can be formed a glass substrate to provide lenticular structures are formed as follows. An IRIS™ LGP plate surface is shown in FIG. 16, which shows an exemplary four step process. It will be understood that the present disclosure is not limited to a particular number of sequence of steps. In a first step, a 1.1 mm thick, 8.5 inch xl 1 inch IRIS™ glass substrate (available from Corning, Incorporated) was obtained and washed using a standard glass cleaning procedure using SemiClean detergent followed by DI water, and stored in proper condition, prior to any subsequent process steps. In a second step, a curable material for screen printing having suitable properties to form a lenticular lens structure of a light guide plate is selected, and a screen with an appropriate mesh size and percentage opening is selected to achieve a desired emulsion thickness with required print features. Then the screen area was flooded with the polymer (an optically clear ink) for the print step, and when sufficient wetting of the screen surface was achieved, the print step was applied using varying print speed (mm/sec), gap (mm) and print pressure. In this step, the wet thickness of the printed ink is controlled. In a third step, radiation is applied to the printed curable material, for example, a post-UV or bake step applied directly to the printed surface. Additional steps include repeating the second and third steps to achieve the repeated desired wet or cured thickness.

[00142] Several mesh sizes (mesh thickness and open area) using stainless steel material having print features of interest were screen printed and evaluated, with the interest of increasing the print heights of the elongate polymeric microstructure. The wet thickness listed in the following tables was calculated using the formula provided by the material supplier. Wet thickness = mesh thickness * open area + emulsion thickness. In all cases, the print widths increased with increasing emulsion thickness which affected the print heights.

Maximum print heights obtained were about 29 pm with aspect ratio (W/H) of about 8.3.

[00143] Table 1

[00144] Table 2

[00145] Examples A-0 are based on MPOSS nano/Texanol/initiator formulation; Examples P-Q are based on MPOSS nano / Dowanol/initiator formulation

[00146] Rheological screening of curable materials was performed. Both shear sweep (viscosity as a function of shear rate 0-100 s ¹ and time) measurements and steady shear recovery measurements were performed on selected materials to understand the viscosity behavior during screen printing.

[00147] Shear sweep from O.l/s to lOO/s was measured to avoid flow instabilities. Results are shown in FIGs. 17 and 18. FIG. 17 is a graph representing steady shear sweep (shear viscosity versus shear rate) for screen printed inks containing Texanol solvent. FIG. 18 is a graph of representing steady shear sweep (shear viscosity versus shear rate) for screen print inks containing diethyleneglycolmonomethyl (Dowanol DPM™ solvent)Results showed all MPOSS nanosilica without solvent, MPOSS nanosilica + 1 wt% 1173 (photoinitiator) + 2 wt% Texanol, MPOSS nanosilica + 1 wt% 1173 (photoinitiator)+ 2 wt% Texanol +2 wt% IPA and MPOSS nanosilica + 1 wt% 1173 (photoinitiator) + 2 wt% IPA were slightly shear thinning and all showed a small amount of thixotropic behavior. Also, as the Texanol (Ester Alcohol, Eastman Chemical Company), and /or Isopropyl alcohol (IPA) amount increased, the viscosity decreased. In contrast, the sample that exhibited the shear thinning was made with dipropyleneglycolmonomethyl ether 2 wt% (DiPGME, Dowanol DPM™) with MPOSS nanosilica + 1 wt% 1173 (photoinitiator) system

[00148] Steady shear with recovery was monitored only by viscosity and was used to see how the structures recovered. The testing was done using the 50 mm Cone and Plate at 23 C. The test sequence was started with a 60 sec hold followed by a 60 sec low shear (0.5 s-l) time sweep to establish the viscosity baseline. The samples were then subjected to a high shear (100 s-l) for 60 sec followed by the low shear for 1000 sec. to monitor the recovery for mixtures : (1) MPOSS nanosilica + 1173 1 wt% + Texanol 2 wt%, (2) MPOSS nanosilica + 1173 1 wt% + Texanol 4 wt%, (3) MPOSS nanosilica + 1173 1 wt% +Texanol 2 wt% + IPA 3 wt%, and (4) MPOSS Nanosilica + 1173 1 wt % + DiPGME 2 wt % or, 5 wt% or 10 wt%. All four samples marked above as 1-4 appeared to have measurable recovery time with the (2) MPOSS nanosilica 1173 1% Tex 4%, sample being the quickest at around 90 sec.

Mixtures (1) and (3) took longer at around 10 min. The mixture (4) with 2 wt% DiPGME took 900 sec, 5 wt% DiPGMEtook > 1000 sec and 10 wt% DiPGME about 900 sec to recover. These samples are plotted separately in FIGs. 19-20 due to their viscosities being much higher than the other three.

[00149] FIG. 21 shows results of light confinement measurements carried out on a glass LGP (middle, WS01486) with screen printed microstructures made according to one or more embodiments of the disclosure compared with on a bare glass LGP (left) and a glass LGP (right) with laminated lenticular film. FIG. 22 is the light confinement in a plot of normalized optical brightness of a glass LGP with screen printed microstructures at 250 mm distance from the input edge as a function of position (mm) and it’s Lorentzian fitting curve which is used to calculate the LDI. The LDI of -81% for 150 mm dimming width is achieved at 250 mm distance from the input edge. FIG. 23 A is an SEM photograph of a top view of screen-printed elongate polymeric microstructures using the MPOSS

nano/Texanol/initiator system: printed 150 um width structures, 1 printed layer resulted in - 20 pm (contact angle - 22-29 deg).

[00150] FIG. 23B is an SEM photograph of a side view of the screen-printed elongate polymeric microstructures shown in FIG. 23 A.

[00151] FIG. 23 C is an SEM photograph of an enlarged side view of a single one of the screen-printed elongate polymeric microstructures shown in FIG. 23B.

[00152] FIG. 24A is an SEM photograph of a top view of screen-printed elongate polymeric microstructures using the MPOSS nano/Texanol/initiator system: printed 2 layers achieved -30 um (contact angle - 40-42 deg) and 3 layers resulted in 40 pm feature heights.

[00153] FIG. 24B is an SEM photograph of a side view of the screen-printed elongate polymeric microstructures shown in FIG. 24A

[00154] FIG. 24C is an SEM photograph of an enlarged side view of a single one of the screen-printed elongate polymeric microstructures shown in FIG. 24B.

[00155] Three layers resulted in 40 pm feature heights.

[00156] FIG. 25 A is an SEM photograph of a side view of screen-printed elongate polymeric microstructures using the MPOSS nano/Dowanol/initiator system based on one printed layer. The printed elongate polymeric microstructures were 120 pm in width. The one printed layer resulted in a microstructure having a height of approximately 22 pm and a contact angle of approximately 26 degrees.

[00157] FIG. 25B is an SEM photograph of a side view of screen-printed elongate polymeric microstructures using the MPOSS nano/Dowanol/initiator system based on two printed layers. Two printed layers achieved a microstructure height of approximately 30 pm and a contact angle in a range of 26-34 degrees.

[00158] According to one or more embodiments, elongate polymeric microstructures comprise a contact angle in a range of about 20 degrees to about 50 degrees.

[00159] According to another aspect of the disclosure, reduction of surface slope angle of waviness of elongate polymeric microstructures on a glass substrate was found to reduce light leakage from a light guide plate containing elongate polymeric microstructures used as lenticular features. In addition, the local dimming index and the straightness (light confinement) decrease with the surface slope angle. Based on modeling results, it was determined that the surface slope angle of the waviness of the elongate polymeric

microstructures is less than 15 degrees, less than 10 degrees, less than 9 degrees, less than 8 degrees, less than 7 degrees, less than 6 degrees, less, than 5 degrees, less than 4 degrees, less than 3 degrees or less than 2 degrees.

[00160] Modeling based on a light guide plate comprising a glass substrate having a refractive index of 1.5, a thickness of 1.1 mm and a length X width of 500 mm X 500 mm with elongate microstructures 70 forming lenticular features formed on a major surface 30 of the glass substrate 28. The elongate polymeric microstructures were similar to those shown in FIG. 3D, with the width W and height H of the lenticular features W=0.3 mm and

H=0.l5mm, and the cross section of the elongate polymeric microstructures had a

semicircular shape. The modeling also included a spacing S between two elongate polymeric microstructures of 0. l5mm. As shown in FIG. 26, the modeling was further based on there being a section 250 beginning at a location 200 mm from the edge surface 29coupled to light sources (not shown). According to the model, the section 250 has a length of 4 mm in which the surface of an elongate polymeric micro structure is waved or wavy along the lenticular direction (Z direction in FIG. 26). According to one or more embodiments, the terms

"waved," "wavy" or "waviness" refer to the upper most surface 71 of the elongate polymeric microstructure 70 including perturbations such that there is a difference in height along the length L of the elongate polymeric microstructure and there is a maximum height Hi of the elongate polymeric microstructure that is greater than a minimum height FL as shown in FIG. 27, which shows a cross-sectional view of an elongate polymeric microstructure 70 taken along line 27-27 of FIG. 26. According to the model, the waviness of section 250 of the elongate polymeric microstructure comprised four wave periods 250a, 250b, 250c and 250d with a period of lmm. The enlarged view in FIG. 27 shows one of the four wave periods 250a. According to the model, the waviness amplitude is determined by the surface slope angle a which is defined by the angle between the lenticular surface and the axis Z, which can be determined by the angle formed between the z axis, which is parallel to the major surface 30 of the glass substrate 28 and a line extending between a first uppermost surface 71 a of the elongate polymeric microstructure at maximum height Hi and a second uppermost surface 7 lb of the elongate polymeric microstructure at minimum height ¾, as shown in FIG. 27.

[00161] The performance of local dimming optics for 1D light confinement (or 1D local dimming) can be evaluated by two parameters: local dimming index (LDI) and Straightness. As shown in FIG. 28, which is a schematic for describing the definitions of the local dimming index (LDI) and the straightness, LDI and Straightness at a distance Z from LED input edge are respectively defined as

[00165] where, L_m is the luminance of the area A_m of zone m (m=n-2, n-l, n, n+l, n+2) at the distance Z from LED input edge.

[00166] FIG. 29 is a graph which shows the light leakage (percentage of total light coupled into the LGP) light as a function of surface slope angle of the lenticular waviness along the lenticular direction based on the modeling. It is clearly seen that the light leakage increases with the increasing of surface slope angle of the waviness of lenticular features.

[00167] FIGS. 30 and 3 lare graphs which show the LDI (for 150 mm dimming width) and the straightness at 450 mm distance from input edge as a function of surface slope angle of the lenticular waviness along the lenticular direction based on the modeling. The LDI decreases and the straightness increases with the increasing of the surface slope angle.

[00168] Based on above modeling results, it was determined that the surface slope angle of the waviness of the elongate polymeric micro structures 70 that provide lenticular features having a surface slope angle of less than 15 degrees, less than 10 degrees, less than 9 degrees, less than 8 degrees, less than 7 degrees, less than 6 degrees, less, than 5 degrees, less than 4 degrees, less than 3 degrees or less than 2 degrees, wherein the surface slope angle is defined by an angle formed between a line parallel to the major surface 30 (which in some embodiments is a light emitting surface) of the glass substrate 28 and a line extending between a first uppermost surface 7la of the elongate polymeric microstructure at maximum height Hi and a second uppermost surface 7 lb of the elongate polymeric microstructure at minimum height ¾ .

[00169] According to one or more embodiments, light guide plates are provided comprising a glass substrate and elongate polymeric micro structures on a major surface of the glass substrate. The elongate polymeric micro structures 70 have a W/H in a range from about 0.1 to about 10, for example from about 2 to 9, from about 2 to about 8, from about 2 to about 7, from about 2.5 to about 6 or from about 2.5 to about 5, including all ranges and subranges therebetween and having a surface slope angle of less than 15 degrees, less than 10 degrees, less than 9 degrees, less than 8 degrees, less than 7 degrees, less than 6 degrees, less, than 5 degrees, less than 4 degrees, less than 3 degrees or less than 2 degrees, wherein the surface slope angle is defined by an angle formed between a line parallel to the major surface 30 (which in some embodiments is a light emitting surface) of the glass substrate 28 and a line extending between a first uppermost surface 7la of the elongate polymeric microstructure at maximum height Hi and a second uppermost surface 7 lb of the elongate polymeric microstructure at minimum height H_{2 .} Furthermore, the elongate polymeric microstructures 70 according to embodiments of the disclosure that have a surface slope angle less than these values exhibit minimal waviness.

[00170] The light guide plates described here can be used in the manufacture of a display, lighting, or electronic device.

[00171] Another aspect of the disclosure pertains to a method of manufacturing a light guide plate. The method according to a first embodiment comprises depositing an array of elongate beads comprising a first layer of curable liquid on a major surface of a glass substrate; at least partially curing the array of elongate beads comprising a first layer of curable liquid with radiation to provide a plurality of at least partially cured elongate first layers spaced apart by distance S; depositing an array of elongate beads comprising a second layer of curable liquid on the plurality of at least partially cured elongate first layers; and at least partially curing the second layer of curable liquid to form an array of elongate polymeric multilayer microstructures, the elongate polymeric multilayer microstructures comprising n layers, wherein n is in a range of from 2 to 10.

[00172] In some embodiments of the method, at least partially curing with radiation occurs less than 30 seconds, 10 seconds or 1 second after the first layer and the second layer have been deposited.

[00173] In some embodiments of the method, the first layer and second layer are deposited by a screen printing process. In some embodiments, the first layer and the second layer are continuously deposited with a nozzle under fluid pressure. In some embodiments, the radiation comprises an ultraviolet lamp.

[00174] The light guide plate formed by the methods described herein according to some embodiments comprises a plurality of elongate polymeric multilayer microstructures on the major surface of the glass substrate, each of the plurality of elongate polymeric multilayer microstructures comprises a surface slope angle of less than 15 degrees, and wherein the surface slope angle is defined by an angle formed between a line parallel to the major surface of the glass substrate and a line extending between a first uppermost surface 7la of the elongate polymeric microstructure at maximum height Hi and a second uppermost surface 7 lb of the elongate polymeric multilayer microstructure at minimum height H_2.

[00175] The light guide plate formed by the methods described herein according to some embodiments comprises a plurality of elongate polymeric multilayer microstructures on the major surface of the glass substrate, each of the plurality of elongate polymeric multilayer microstructures, each of the plurality of elongate polymeric multilayer microstructures having a maximum height H and a width W measured at one-half of the maximum height (H/2) and comprising an aspect ratio W/H in a range of from about 0.1 to about 10.

[00176] In some embodiments, the light guide plate formed by the methods described herein comprises a plurality of elongate polymeric multilayer microstructures on the major surface of the glass substrate, each of the plurality of elongate polymeric multilayer microstructures, each of the plurality of elongate polymeric multilayer microstructures having a maximum height H and a width W measured at one-half of the maximum height (H/2) and comprising an aspect ratio W/H in a range of from about 0.1 to about 10.

[00177] Another aspect of the disclosure pertains to a method of forming a light guide plate comprising depositing a curable liquid on a major surface of a glass substrate to form an array of elongate, spaced apart first curable liquid layers; at least partially curing the array of elongate, spaced apart curable liquid layers to provide an array of spaced apart at least partially cured polymeric layers; depositing a curable liquid on the array of spaced apart at least partially cured polymeric layers to form an array of elongate, spaced apart second curable liquid layers; and at least partially curing the curable liquid on the array of spaced apart at least partially cured polymeric layers to form an array of elongate polymeric multilayer micro structures, the array elongate polymeric multilayer microstructures comprising n layers, wherein n is in a range of from 2 to 10. In some embodiments of the instant method, each of the array of elongate polymeric multilayer microstructures having a maximum height H and a width W measured at one-half of the maximum height (H/2) such that the elongate polymeric microstructures have an aspect ratio W/H for 1D dimming of LED light. In some embodiments of the instant method, the light guide plate formed by the method comprises a plurality of elongate polymeric multilayer micro structures on the major surface of the glass substrate, each of the plurality of elongate polymeric multilayer microstructures comprises a surface slope angle of less than 15 degrees, and wherein the surface slope angle is defined by an angle formed between a line parallel to the major surface of the glass substrate and a line extending between a first uppermost surface 7la of the elongate polymeric microstructure at maximum height Hi and a second uppermost surface 7 lb of the elongate polymeric multilayer microstructure at minimum height H_2.

[00178] In some embodiments of the method, the light guide plate formed by the method comprises a plurality of elongate polymeric multilayer microstructures on the major surface of the glass substrate, each of the plurality of elongate polymeric multilayer micro structures, each of the plurality of elongate polymeric multilayer microstructures having a maximum height H and a width W measured at one-half of the maximum height (H/2) and comprising an aspect ratio W/H in a range of from about 0.1 to about 10.

[00179] Ranges expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, another embodiment includes 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 embodiment. 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.

[00180] Directional terms as used herein, for example up, down, right, left, front, back, top, bottom are made only with reference to the figures as drawn and are not intended to imply absolute orientation. [00181] 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, nor that with any apparatus, specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. As used herein, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a" component includes aspects having two or more such components, unless the context clearly indicates otherwise.

[00182] It will be apparent to those skilled in the art that various modifications and variations can be made to embodiments of the present disclosure without departing from the spirit and scope of the disclosure. Thus, it is intended that the present disclosure cover such modifications and variations provided they come within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A light guide plate comprising:

a glass substrate including an edge surface and two major surfaces; and

a plurality of elongate polymeric multilayer microstructures on at least one of the major surfaces, each elongate multilayer micro structure having a maximum height H and a width W measured at one-half of the maximum height (H/2) and further comprising an aspect ratio W/H in a range of from about 0.1 to about 10.

2. The light guide plate of claim 1, wherein the aspect ratio is in a range of from about 2 to about 8.

3. The light guide plate of claim 1, wherein the aspect ratio is in a range of from about 2.5 to about 6.

4. The light guide plate of claim 1, wherein the height H of each elongate polymeric multilayer micro structure does not exceed 50 pm.

5. The light guide plate of claim 1, wherein W is between about 50 pm and about 500 pm.

6. The light guide plate of claim 1, wherein each elongate polymeric multilayer microstructure comprises n layers, wherein n is in a range of from 3 to 10.

7. The light guide plate of claim 1, wherein a first spacing S between two adjacent elongate polymeric multilayer microstructures of the plurality of microstructures in a first direction is in a range of from about 0.01 *W and 4*W.

8. The light guide plate of claim 1, wherein at least one of the plurality of elongate polymeric multilayer microstructures further comprises a length L, and wherein another one of the plurality of elongate polymeric multilayer microstructures has a length L2 different from L.

9. The light guide plate of claim 1, wherein the glass substrate comprises, on a mol% oxide basis: 50-90 mol% Si0₂,

0-20 mol% AI2O3,

0-20 mol% B2O3, and

0-25 mol% R_xO,

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.

10. The light guide plate of claim 1, wherein a thickness t of the glass substrate ranges from about 0.1 mm to about 3 mm.

11. The light guide plate of claim 1, wherein the plurality of elongate polymeric multilayer microstructures comprises a UV curable or thermally curable polymer.

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

13. The light guide plate of claim 1, wherein each elongate polymeric multilayer microstructure comprises a surface slope angle of less than 15 degrees, and wherein the surface slope angle is defined by an angle formed between a line parallel to the light emitting surface of the glass substrate and a line extending between a first uppermost surface of the elongate polymeric microstructure at maximum height Hi and a second uppermost surface of the elongate polymeric microstructure at minimum height ¾.

14. The light guide plate of claim 13, wherein the surface slope angle is less than 10 degrees.

15. The light guide plate of claim 13, wherein the surface slope angle is less than 4 degrees.

16. The light guide plate of claim 13, wherein the surface slope angle is less than 2 degrees.

17. A light guide plate comprising:

a glass substrate including an edge surface and at least two major surfaces; and a plurality of elongate polymeric microstructures on at least one of the major surfaces, each elongate polymeric micro structure comprising a surface slope angle of less than 15 degrees, and wherein the surface slope angle is defined by an angle formed between a line parallel to the light emitting surface of the glass substrate and a line extending between a first uppermost surface of the elongate polymeric micro structure at maximum height Hi and a second uppermost surface of the elongate polymeric microstructure at minimum height H_2.

18. The light guide plate of claim 17, wherein the surface slope angle is less than 10 degrees.

19. The light guide plate of claim 17, wherein the surface slope angle is less than 4 degrees.

20. The light guide plate of claim 17, wherein the surface slope angle is less than 2 degrees.

21. The light guide plate of claim 17, wherein each elongate polymeric microstructure comprises n layers, and wherein n is in a range of from 2 to 10.

22. The light guide plate of claim 21, wherein n is in a range of from 2 to 5.

23. A display, lighting, or electronic device comprising the light guide plate of claims 1 to 22

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

depositing a first layer of curable liquid on a major surface of a glass substrate as a first array of elongate liquid beads;

at least partially curing with radiation the first layer of curable liquid to provide an array of at least partially cured elongate microstructures spaced apart by distance S;

depositing a second layer of curable liquid on the first array at least partially cured elongate beads as a second array of elongate liquid beads;

at least partially curing with radiation the second layer of curable liquid to provide a two layer array of at least partially cured elongate microstructures; and

optionally forming an additional layer of curable liquid on the two layer array of at least partially cured elongate micro structures to provide a multilayer array of elongate polymeric multilayer microstructures comprising n layers, wherein n is in a range of from 2 to 10.

25. The method of claim 24, wherein at least partially curing with radiation occurs less than 30 seconds after the first layer of curable liquid has been deposited and less than 30 seconds after the second layer of curable liquid have been deposited.

26. The method of claim 24, wherein at least partially curing with radiation occurs less than 10 seconds after the first layer of curable liquid has been deposited and less than 10 seconds after the second layer of curable liquid has been deposited.

27. The method of claim 24, wherein at least partially curing with radiation occurs less than 5 seconds after the first layer of curable liquid has been deposited and less than 5 seconds after the second layer of curable liquid has been deposited.

28. The method of claim 24, wherein at least partially curing with radiation occurs less than 1 second after the first layer of curable liquid has been deposited and the second layer of curable liquid has been deposited.

29. The method of claim 24, wherein the first layer and second layer are deposited by a screen printing process.

30. The method of claim 29, wherein the radiation comprises ultraviolet light.

31. The method of claim 29, wherein each elongate polymeric multilayer microstructure comprises a surface slope angle of less than 15 degrees, and wherein the surface slope angle is defined by an angle formed between a line parallel to the major surface of the glass substrate and a line extending between a first uppermost surface of the elongate polymeric microstructure at maximum height Hi and a second uppermost surface of the elongate polymeric multilayer microstructure at minimum height H_2.

32. The method of claim 29, each elongate polymeric multilayer microstructure has a maximum height H and a width W measured at one-half of the maximum height (H/2) and comprising an aspect ratio W/H in a range of from about 0.1 to about 10.

33. The method of claim 24, wherein the first layer and the second layer are continuously deposited with a nozzle under fluid pressure.

34. The method of claim 32, wherein the radiation comprises ultraviolet light.

35. The method of claim 34, wherein each elongate polymeric multilayer microstructure comprises a surface slope angle of less than 15 degrees, and wherein the surface slope angle is defined by an angle formed between a line parallel to the major surface of the glass substrate and a line extending between a first uppermost surface of the elongate polymeric microstructure at maximum height Hi and a second uppermost surface of the elongate polymeric multilayer microstructure at minimum height H_2.

36. The method of claim 34, wherein each elongate polymeric multilayer micro structure have a maximum height H and a width W measured at one-half of the maximum height (H/2) and further comprise an aspect ratio W/H in a range of from about 0.1 to about 10.

37. The method of claim 24, wherein an inkjet printer is used for depositing the first layer and depositing the second layer.

38. A method of forming a light guide plate comprising:

depositing a curable liquid on a major surface of a glass substrate to provide an array of elongate, spaced apart first curable liquid layers;

at least partially curing the array of elongate, spaced apart curable liquid layers to form an array of spaced apart at least partially cured polymeric layers;

depositing additional curable liquid on the array of spaced apart at least partially cured polymeric layers to form an array of elongate, spaced apart second curable liquid layers;

at least partially curing the array of elongate, spaced apart second curable liquid layers to form an array of at least partially cured elongate polymeric multilayer microstructures; and

optionally forming an additional array of at least partially cured elongate polymeric microstructures on the array of at least partially cured elongate polymeric multilayer microstructures so that the array of at least partially cured elongate polymeric multilayer microstructures comprises n layers, wherein n is in a range of from 2 to 10.

39. The method of claim 38, wherein each elongate polymeric multilayer microstructure have a maximum height H, a width W measured at one-half of the maximum height (H/2) and an aspect ratio W/H for 1D dimming of LED light.

40. The method of claim 38, wherein each elongate polymeric multilayer microstructure comprises a surface slope angle of less than 15 degrees, and wherein the surface slope angle is defined by an angle formed between a line parallel to the major surface of the glass substrate and a line extending between a first uppermost surface of the elongate polymeric microstructure at maximum height Hi and a second uppermost surface of the elongate polymeric multilayer microstructure at minimum height H_2.

41. The method of claim 38, wherein wherein each elongate polymeric multilayer microstructure has a maximum height H and a width W measured at one-half of the maximum height (H/2) and an aspect ratio W/H in a range of from about 0.1 to about 10.

42. The method of claim 38, wherein an inkjet printer is used for depositing the curable liquid and depositing the additional curable liquid.