IL324544A - Light guide plates, lighting devices including the same, and methods for manufacturing the same - Google Patents

Description

SP23-118PCT LIGHT GUIDE PLATES, LIGHTING DEVICES INCLUDING THE SAME, AND METHODS FOR MANUFACTURING THE SAME Cross -Reference To Related applications [0001]This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application No. 63/466,245 filed May 12, 2023, the content of which is incorporated herein by reference in its entirety.

Field [0002]The present disclosure relates to transparent lighting devices and, more particularly, to edge-lit light guide plates for such transparent lighting devices that incorporate scattering particles to direct light from major surfaces of the light guide plates.

Background [0003]Conventional light guide plates (LGPs) may use printed patterns or direct laser engraving to provide light scattering functionality. However, those patterns or engravings may be visible, decreasing the quality of lighting when transparent lighting is desired. One option to hide visible patterns or engravings in LGPs is to use a diffuser plate. However, such plates can make the LGP translucent. As such, existing LGPs may provide transparent lighting with visible patterns or engravings or translucent edge-lit lighting. Consequently, there exists a need for LGP lighting solutions that address these and other issues.

Summary [0004]The following summary is a brief description of certain aspects of the present disclosure. The summary should not be considered as limiting of the breadth, scope, or applicability of the present disclosure.

[0005]According to aspect (1), a light guide plate is provided. The light guide plate comprises: a first transparent substrate having a first major surface; a first carrier layer positioned on or over the first major surface; first scattering particles dispersed throughout the first carrier layer, wherein the first carrier layer is configured as an optically clear adhesive (OCA) film, an optically clear resin (OCR), or a hard coating film that is transparent and exhibits at least H pencil hardness.

SP23-118PCT

[0006]According to aspect (2), the light guide plate of aspect (1) is provided, wherein the first carrier layer is configured as the OCA film or the OCR and a first side of the first carrier layer is positioned on the first major surface of the first transparent substrate.

[0007]According to aspect (3), the light guide plate of aspect (1) is provided, wherein the first carrier layer is configured as the OCA film and a first side of the first carrier layer is positioned over the first major surface of the first transparent substrate.

[0008]According to aspect (4), the light guide plate of aspect (3) is provided, further comprising: a second carrier layer positioned between and contacting the first transparent substrate and the first side of the first carrier layer; and second scattering particles dispersed throughout the second carrier layer.

[0009]According to aspect (5), the light guide plate of aspect (4) is provided, wherein the second carrier layer is positioned intermittently between and contacting the first transparent substrate and the first side of the first carrier layer.

[0010]According to aspect (6), the light guide plate of aspect (4) or aspect (5) is provided, wherein the second carrier layer is different than the first carrier layer.

[0011]According to aspect (7), the light guide plate of any one of aspects (4) to (6) is provided, wherein the second carrier layer is a matrix.

[0012]According to aspect (8), the light guide plate of any one of aspects (4) to (7) is provided, wherein the second scattering particles comprise BaTiO3, SnO2, SiO2, TiO2, ZrO2, or combinations thereof.

[0013]According to aspect (9), the light guide plate of any one of aspects (1) to (8) is provided, further comprising a second transparent substrate positioned on a second side of the first carrier layer, the second side opposite the first side of the first carrier layer.

[0014]According to aspect (10), the light guide plate of aspect (9) is provided, wherein the second transparent substrate comprises a polymeric material or a glass material.

[0015]According to aspect (11), the light guide plate of any one of aspects (1) to (8) is provided, wherein the hard coating film is positioned on a second side of the first carrier layer, the second side opposite the first side of the first carrier.

[0016]According to aspect (12), the light guide plate of any one of aspects (1) to (11) is provided, wherein the first scattering particles comprise BaTiO3, SnO2, SiO2, TiO2, ZrO2, or combinations thereof.

SP23-118PCT

[0017]According to aspect (13), the light guide plate of aspect (1) is provided, wherein the first carrier layer is configured as the hard coating film positioned on the first major surface of the first transparent substrate.

[0018]According to aspect (14), the light guide plate of aspect (13) is provided, wherein the first scattering particles comprise BaTi03, SnO2, Si02, Ti02, ZrO2, or combinations thereof.

[0019]According to aspect (15), the light guide plate of aspect (13) or aspect (14) is provided, wherein the hard coating film comprises acrylic polymer and the first scattering particles comprise SiO2.

[0020]According to aspect (16), the light guide plate of aspect (13) or aspect (14) is provided, wherein the hard coating film comprises acrylic monomer and the first scattering particles comprise BaTiO3, SnO2, TiO2, ZrO2, or combinations thereof.

[0021]According to aspect (17), the light guide plate of any one of aspects (1) to (16) is provided, wherein the first transparent substrate comprises a polymeric material or a glass material.

[0022]According to aspect (18), the light guide plate of any one of aspects (1) to (17) is provided, wherein a haze of the light guide plate is in a range of from about 1% to about 5%.

[0023]According to aspect (19), the light guide plate of any one of aspects (1) to (18) is provided, wherein an optical transmittance of the light guide plate is greater than about 80% over a length of 500 mm in visible region of the spectrum.

[0024]According to aspect (20), a method for manufacturing a light guide plate is provided. The method comprises: embedding first scattering particles in a first carrier layer; and positioning the first carrier layer on or over a first major surface of a first transparent substrate after the embedding, wherein the first carrier layer is an optically clear adhesive (OCA) film, an optically clear resin (OCR), or a hard coating film that is transparent and exhibits at least H pencil hardness.

[0025]According to aspect (21), the method of aspect (20) is provided, wherein the embedding comprises adding the first scattering particles to a first material of the first carrier layer when the first material is in a liquid state.

SP23-118PCT

[0026]According to aspect (22), the method of aspect (21) is provided, wherein, when the first carrier layer is the OCA film, the first material is converted from the liquid state to a semisolid state or a solid state prior to the positioning.

[0027]According to aspect (23), the method of aspect (22) is provided, wherein the positioning comprises bonding a first side of the first carrier layer in the semisolid state or the solid state to the first major surface of the first transparent substrate.

[0028]According to aspect (24), the method of aspect (23) is provided, further comprising positioning a second transparent substrate on a second side of the first carrier layer, the second side opposite the first side of the first carrier layer.

[0029]According to aspect (25), the method of aspect (23) is provided, further comprising forming the hard coating film on a second side of the first carrier layer, the second side opposite the first side of the first carrier layer.

[0030]According to aspect (26), the method of aspect (21) is provided, wherein, when the first carrier layer is the OCR, the positioning comprises coating the first carrier layer in the liquid state on the first major surface of the first transparent substrate.

[0031]According to aspect (27), the method of aspect (26) is provided, further comprising positioning a second transparent substrate on the first carrier layer, the second side opposite the first side of the first carrier layer.

[0032]According to aspect (28), the method of aspect (21) is provided, wherein, when the first carrier layer is the OCR, the positioning comprises: positioning a second transparent substrate proximate the first transparent substrate, and injecting the first carrier layer in the liquid state between the first transparent substrate and the second transparent substrate.

[0033]According to aspect (29), the method of aspect (26) is provided, further comprising forming the hard coating film on a second side of the first carrier layer, the second side opposite the first side of the first carrier layer.

[0034]According to aspect (30), the method of aspect (22) is provided, wherein the positioning comprises positioning a first side of the first carrier layer in the semisolid state or the solid state over the first major surface of the first transparent substrate.

[0035]According to aspect (31), the method of aspect (30) is provided, further comprising forming a second carrier layer on the first major surface of the first transparent substrate, the SP23-118PCT second carrier layer different than the first carrier layer and comprising second scattering particles dispersed throughout the second carrier layer.

[0036]According to aspect (32), the method of aspect (31) is provided, wherein the positioning further comprises positioning the first side of the first carrier layer on the second carrier layer such that the second carrier layer is positioned between and contacting the first transparent substrate and the first side of the first carrier layer.

[0037]According to aspect (33), the method of aspect (32) is provided, wherein the second carrier layer is formed intermittently between and contacting the first transparent substrate and the first side of the first carrier layer.

[0038]According to aspect (34), the method of aspect (33) is provided, further comprising positioning a second transparent substrate on a second side of the first carrier layer, the second side opposite the first side of the first carrier layer.

[0039]According to aspect (35), the method of aspect (33) is provided, further comprising forming the hard coating film on a second side of the first carrier layer, the second side opposite the first side of the first carrier layer.

[0040]According to aspect (36), the method of aspect (21) is provided, wherein, when the first carrier layer is the hard coating film, the positioning comprises coating the first carrier layer in the liquid state on the first major surface of the first transparent substrate.

[0041]According to aspect (37), the method of aspect (21) is provided, further comprising: modulating a concentration of the first scattering particles added to the first material to form discrete volumes of the first material with different concentrations of the first scattering particles, and selecting one of the discrete volumes of the first material so that first carrier layer has a target concentration of the first scattering particles.

Brief Description of the Drawings [0042]Various exemplary embodiments of the present disclosure are described in detail below with reference to the following drawings. The drawings are provided for purposes of illustration only and merely depict exemplary embodiments of the present disclosure to facilitate the understanding of the present disclosure. Therefore, the drawings should not be considered as limiting of the breadth, scope, or applicability of the present disclosure. It should SP23-118PCT be noted that for clarity and ease of illustration these drawings are not necessarily drawn to scale.

[0043]FIG. lisa schematic cross-sectional view of a light guide plate according to one or more embodiments;

[0044]FIG. 2 is a schematic cross-sectional view of a light guide plate according to one or more embodiments;

[0045] FIG. 3is a schematic cross-sectional view of a light guide plate according to one or more embodiments;

[0046]FIG. 4 is a schematic cross-sectional view of a light guide plate according to one or more embodiments;

[0047]FIG. 5 is a top plan view of a lighting device that includes a light guide plate configured to form text according to one or more embodiments;

[0048]FIG. 6 is a top plan view of a lighting device that includes a light guide plate configured to form symbols according to one or more embodiments;

[0049] FIG. 7 is a photo of a light guide plate fabricated according to the Examples;

[0050] FIG. 8 and FIG. 9 are photos of a lighting device with a light guide plate in a lightoff state and a light on state, respectively;

[0051]FIG. 10 illustrates luminous distribution of a particle-embedded carrier layer disposed on the light guide plate of FIG. 8 and FIG. 9;

[0052]FIG. 11 is a photo of an illumination of a lighting device that includes a light guide plate with a particle-embedded carrier layer in the form of an optically clear resin (OCR); and

[0053]FIG. 12 is a photo of an illumination of a lighting device that includes a light guide plate without a particle-embedded carrier layer.

Detailed Description [0054]For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is understood that no limitation to the scope of the disclosure is thereby intended. It is further understood that the present disclosure includes any alterations and modifications to the illustrated embodiments and includes further applications SP23-118PCT of the principles disclosed herein as would normally occur to one skilled in the art to which this disclosure pertains.

[0055]As used herein, the term “and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

[0056]In this document, relational terms, such as first and second, top and bottom, and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0057]As used herein, the term “about ” means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. When the term “about ” is used in describing a value or an end-point of a range, the disclosure should be understood to include the specific value or end-point referred to. Whether or not a numerical value or end-point of a range in the specification recites “about, ” the numerical value or end-point of a range is intended to include two embodiments: one modified by “about, ” and one not modified by “about. ” It will be further understood that the end-points of each of the ranges are significant both in relation to the other end-point, and independently of the other end-point.

[0058]The terms “substantial, ” “substantially, ” and variations thereof as used herein, unless defined elsewhere in association with specific terms or phrases, are intended to note that a described feature is equal or approximately equal to a value or description. For example, a “substantially planar” surface is intended to denote a surface that is planar or approximately planar. Moreover, “substantially ” is intended to denote that two values are equal or approximately equal. In some embodiments, “substantially ” may denote values within about 10% of each other, such as within about 5% of each other, or within about 2% of each other.

SP23-118PCT

[0059]Directional terms as used herein —for example up, down, right, left, front, back, top, bottom, above, below, and the like—are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

[0060]As used herein the terms "the," "a," or "an," mean "at least one," and should not be limited to "only one" unless explicitly indicated to the contrary. Thus, for example, reference to "a component" includes embodiments having two or more such components unless the context clearly indicates otherwise.

[0061]Various embodiments of the disclosure will now be discussed with reference to FIGS.1-6, which illustrate exemplary components and aspects of light guide plates and lighting devices with such light guide plates disclosed herein. The following general description is intended to provide an overview of the claimed plates and 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.

[0062]FIGS. 1-4 illustrate schematic cross-section views of a light guide plate (LGP) 1in various embodiments. FIGS. 5 and 6 illustrate top plan views of the LGP 100 incorporated in a lighting device 500. The LGP 100 includes a first transparent substrate 104 having a first major surface 108 and a second major surface 112 opposite the first major surface 108. In embodiments, the first and second major surfaces 108, 112 are substantially parallel and planar. The first and second major surfaces 108, 112 can be non-parallel and/or not planar in embodiments.

[0063]The first transparent substrate 104 can have any dimensions, such as a length (left and right relative to the drawing views), a width (into and out of the drawing views), and a thickness (up and down relative to the drawing views), which dimensions can vary depending on the display or lighting application. In embodiments, the length can range from about 0.m to about 10 m, such as from about 0.1 m to about 5 m, from about 0.5 m to about 2.5 m, or from about 1 m to about 2 m, including all ranges and subranges therebetween. Similarly, the width can range from about 0.01 m to about 10 m, such as from about 0.1 m to about 5 m, from about 0.5 m to about 2.5 m, or from about 1 m to about 2 m, including all ranges and subranges therebetween.

[0064]The first transparent substrate 104 can have any shape. For example, the first transparent substrate 104 can be square, such as depicted in FIGS. 5-9, 10, and 11. While a SP23-118PCT square first transparent substrate 104 is illustrated in the figures, it is to be understood that the first transparent substrate can have any regular or irregular shape as appropriate to produce a desired light distribution for a chosen application. The first transparent substrate 104 can comprise four edges as illustrated in FIGS. 5-9, 10, and 11, or it can comprise more than four edges, e.g., a multi-sided polygon. In embodiments, the first transparent substrate 104 can comprise less than four edges, e.g., a triangle. By way of a non-limiting example, the first transparent substrate 104 can comprise a rectangular, square, or rhomboid sheet having four edges, although other shapes and configurations are intended to fall within the scope of the disclosure including those having one or more curvilinear portions or edges.

[0065]According to embodiments, the first transparent substrate 104 can comprise any transparent material used in the art for lighting and display applications. As used herein, the term “transparent” is intended to denote that the first transparent substrate 104 has an optical transmission of greater than about 80% over a length of 500 mm in the visible region of the spectrum (-420-750 nm). For instance, an exemplary transparent material may have greater than about 85% transmittance in the visible light range over a length of 500 mm, such as greater than about 90%, greater than about 95%, or greater than about 99% transmittance, including all ranges and subranges therebetween.

[0066]The optical properties of the first transparent substrate 104 may be affected by the refractive index of the transparent material. According to embodiments, the first transparent substrate 104 may have a refractive index ranging from about 1.3 to about 1.8, such as from about 1.35 to about 1.7, from about 1.4 to about 1.65, from about 1.45 to about 1.6, or from about 1.5 to about 1.55, including all ranges and subranges therebetween.

[0067]The first transparent substrate 104 can comprise a polymeric material, such as plastics, e.g., polymethyl methacrylate (PMMA), methyl methacrylate styrene (MS), poly dimethylsiloxane (PDMS), or other similar materials. The first transparent substrate 1can also comprise a glass material, such as aluminosilicate, alkali-aluminosilicate, borosilicate, alkali-borosilicate, aluminoborosilicate, alkali-aluminoborosilicate, soda lime, or other suitable glasses. Non-limiting examples of commercially available glasses suitable for use as a glass light guide include, for instance, EAGLE XG®, Lotus™, Willow®, Iris™, and Gorilla® glasses from Corning Incorporated.

[0068]The LGP 100 further comprises a first carrier layer 116 positioned on or over the first major surface 104. As described in more detail herein, the first carrier layer 116 is SP23-118PCT configured as optically clear adhesive (OCA) film 120, an optically clear resin (OCR) 124, or a hard coating film 128 that is transparent and exhibits a minimum pencil hardness (e.g., H pencil hardness).

[0069]As used herein, an “OCA film ” refers to an adhesive-type material in semisolid or solid form. The OCA film can be cured using ultraviolet (UV), moisture, and/or thermal curing. In embodiments, a thickness of the OCA film may be less than 0.2 mm. The transparency of the OCA film is very high (e.g., > 99%). As used herein, an “OCR” refers to a resin-type material in liquid form. The OCR can be cured using UV and/or thermal curing. In embodiments, a thickness of the OCR may be greater than 0.1 mm. The transparency of the OCA film is very high (e.g., > 99%). The OCA film and the OCR may be formed from acrylic, epoxy, silicon, urethane, and other optically clear bonding materials.

[0070]The LGP 100 further comprises first scattering particles 132 dispersed throughout the first carrier layer 116. In embodiments, the first scattering particles 132 comprise TiO2, ZrO2, BaTiO3, SnO2, In203, HfO, Nb205, Ta205, CaCO3, BaSO4, or combinations thereof. In embodiments, the first scattering particles 132 comprise BaTiO3, SnO2, SiO2, TiO2, ZrO2, or combinations thereof. The first scattering particles 132 can comprise other materials or other oxide in addition to those disclosed herein. In other words, the material and/or composition of the first scattering particles is not limited to those materials disclosed herein.

[0071]In embodiments, the first scattering particles 132 can each have a maximum size (e.g., a maximum diameter) of equal to or less than 5 pm or equal to or less than 1 pm. In embodiments, the first scattering particles can have an average size (e.g., an average diameter) in a range of from about 100 nm to about 500 nm. When the average size of the first scattering particles 132 ranges from about 100 nm to about 500 nm and the maximum size of the first scattering particles 132 is 1 pm or less, the first scattering particles 132 are not identified by the naked eye. Accordingly, the light transmittance of the LGP 100 in a turned-off state is maintained high, thereby providing a high level of user experience to a user using the lighting device 500.

[0072]Referring now to FIG. 1, further embodiments of the LGP 100 are depicted. In FIG. 1, the first carrier layer 116 is configured as the hard coating film 128. As shown, the hard coating film 128 is positioned on the first major surface 108 of the first transparent substrate 104. In embodiments, the hard coating film 128 and the first scattering particles 132 can have different materials. In embodiments, for example, the hard coating film 128 comprises acrylic SP23-118PCT polymer and the first scattering particles 132 comprise Si02. In further embodiments, the hard coating film 128 comprises acrylic monomer and the first scattering particles 132 comprise BaTi03, SnO2, Ti02, ZrO2, or combinations thereof. In embodiments, the hard coating film 128 has an optical transmission similar to that of the first transparent substrate 104. In embodiments, the minimum pencil hardness of the hard coating film 128 is at least 2H pencil hardness, or at least 3H pencil hardness.

[0073]Referring now to FIG. 2, further embodiments of the LGP 100 are depicted. In FIG. 2, the first carrier layer 116 is the OCA film 120 or the OCR 124 and a first side 136 of the first carrier layer 116 is positioned on the first major surface 108 of the first transparent substrate 104. The first carrier layer 116 has a second side 138 opposite the first side 136. In one configuration of the embodiments depicted in FIG. 2, the hard coating film 128 is positioned on the second side 138 of the first carrier layer 166.

[0074]In another configuration of the embodiments depicted in FIG. 2, the LGP 1further comprises a second transparent substrate 140 positioned on the second side 138 of the first carrier layer 116. In embodiments, the second transparent substrate 140 can have the same or substantially the same compositions, physical attributes, and optical properties as the first transparent substrate 104. In embodiments, the second transparent substrate 140 can differ with respect to one or more of the compositions, physical attributes, and optical properties of the first transparent substrate 104.

[0075]Referring now to FIGS. 3 and 4, further embodiments of the LGP 100 are depicted. In FIGS. 3 and 4, the first carrier layer 116 is configured as the OCA film 120 and the first side 136 of the first carrier layer 116 is positioned over the first major surface 108 of the first transparent substrate 104. In the configuration in which the first carrier layer 116 is positioned over the first major surface 108, the first carrier layer 116 may not contact the first major surface 108 of the first transparent substrate 104. In the embodiments of FIGS. 3 and 4, the LGP 100 further comprises a second carrier layer 144 positioned between and contacting the first major surface 108 of the first transparent substrate 104 and the first side 136 of the first carrier layer 116. The LGP 100 also includes second scattering particles 148 dispersed throughout the second carrier layer 144.

[0076]In embodiments, as shown in FIG. 4, the second carrier layer 144 is configured to be positioned intermittently between and contacting the first major surface 108 of the first transparent substrate 104 and the first side 136 of the first carrier layer 116. Such intermittent SP23-118PCT positioning of the second carrier layer 144 with the second scattering particles 148 can define one or more patterns that enable the LGP 100 to illuminate letters 520 (FIG. 5), signals 5(FIG. 5), pictures, designs, etc. out of the surfaces of the first transparent substrate 104 and/or the second transparent substrate 140 when the LGP 100 includes the second transparent substrate 140.

[0077]In embodiments, the second carrier layer 144 can be different than the first carrier layer 116. For example, the second carrier layer 144 may comprise a matrix within which the second scattering particles 148. The matrix can comprise, for example, acryl resin, melamine resin, nylon, polystyrene, polycarbonate, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyethylene, polymethyl methacrylate, tetrafluoroethylene, polyethylene trifluoro chloride, or polytetrafluoroethylene. In embodiments, the matrix can include an organic-inorganic composite material. The matrix can be transparent. The matrix can have a refractive index of about 1.3 to about 1.7.

[0078]In embodiments, the second scattering particles 148 can have the same or substantially the same compositions, physical attributes, and optical properties as the first scattering particles 132. In embodiments, the second scattering particles 148 can differ with respect to one or more of the compositions, physical attributes, and optical properties of the first scattering particles 132.

[0079]The haze of the LGP 100 can be about 30% or less, and the transmittance of the LGP 100 can be about 50% or more. More desirably, the transmittance of the LGP 100 can be equal to or greater than 80%, such as in a range of from about 80% to about 89%.

[0080]According to embodiments, the haze of the LGP 100 may range from about 0.1% to about 5%. According to embodiments, the haze of the LGP 100 may be about 0.5% or more. According to embodiments, the haze of the LGP 100 may be about 1% or more. According to embodiments, the haze of the LGP 100 may be about 1.5% or more. According to embodiments, the haze of the LGP 100 may be about 4.5% or less. According to embodiments, the haze of the LGP 100 may be about 4% or less. According to embodiments, the haze of the LGP 100 may be about 3.5% or less. According to embodiments, the haze of the LGP 100 may be about 3% or less. According to embodiments, the haze of the LGP 100 may be about 2.5% or less. According to embodiments, the haze of the LGP 100 may be about 2% or less. In embodiments, haze below 1% can lose scattering power and haze over 5% can lose transparency.

SP23-118PCT

[0081]The haze of the LGP 100 is a ratio of the amount of light scattered by the LGP 1to the amount of light incident on the LGP 100 when the light passes through the LGP 100. The transmittance of the LGP 100 is a ratio of the amount of light output through the LGP 1to the amount of light incident on the LGP 100 when the light passes through the LGP 100.

[0082]The haze and the transmittance of the LGP 100 may be measured under standard temperature and pressure (STP) conditions. The haze and the transmittance of the LGP 1may be measured by any suitable haze meter or haze measurement system. An example of a haze meter capable of measuring haze and transmittance of the LGP 100 is Hazegard manufactured by BYK Gardner. Hazegard is capable of simultaneous measurement of the haze and transmission according to ASTM D1003 - illuminants C and A (a non-compensated method) or according to ISO 13468 - illuminant D65 (a compensation method).

[0083]Referring now to FIGS. 5 and 6, embodiments of the (transparent) lighting device 500 are depicted. The lighting device 500 comprises the LGP 100 in any of the embodiments described herein. In embodiments, the lighting device 500 further comprises a frame 5configured to surround the LGP 100. The lighting device 500 further comprise light sources 508 disposed between the frame 504 and the LGP 100 such that the light sources 508 are positioned adjacent an edge or edge surface of the LGP 100. The lighting device 500 may include the light sources 508 in a number corresponding to a shape of the LGP 100. For example, when the LGP 100 substantially has a square shape, as in the exemplary embodiments, the light device 500 may include four light sources 508 respectively corresponding to four edges of the square, as shown in FIGS. 5 and 6.

[0084]A method for manufacturing a LGP according to example embodiments is now described. To facilitate an understanding of the method, reference will be made to the embodiments of the LGP 100 described herein with reference to FIGS. 1-6.

[0085]In embodiments, the method comprises embedding first scattering particles 132 in a first carrier layer 116 and positioning the first carrier layer 116 on or over a first major surface 108 of a first transparent substrate 104 after the embedding. In embodiments, the first carrier layer 116 is an optically clear adhesive (OCA) film 120, an optically clear resin (OCR) 124, or a hard coating film 128 that is transparent and exhibits at least H pencil hardness.

[0086]In embodiments, the embedding comprises adding the first scattering particles 1to a first material of the first carrier layer 116 when the first material is in a liquid state.

SP23-118PCT

[0087]Referring again to FIG. 1, when the first carrier layer 116 is to be configured as the hard coating film 128, the positioning comprises coating the first carrier layer 116 in the liquid state on the first major surface 108 of the first transparent substrate 104.

[0088]Referring again to FIG. 2, when the first carrier layer 116 is to be configured as the OCR 124, the positioning comprises coating the first carrier layer 116 in the liquid state on the first major surface 108 of the first transparent substrate 104. In one configuration, the method further comprises forming the hard coating film 128 on a second side 138 of the first carrier layer 116. The second side 138 of the first carrier layer 116 is opposite the first side 136 of the first carrier layer 116.

[0089]In another configuration, the method further comprises positioning a second transparent substrate 140 on the LGP 100. In a first configuration of the positioning, the method comprises positioning the second transparent substrate 140 on the first carrier layer 116. In a second configuration of the positioning, the method comprises positioning the second transparent substrate 140 proximate the first transparent substrate 104 and, then, injecting the first carrier layer 116 in the liquid state between the first transparent substrate 104 and the second transparent substrate 140.

[0090]Referring still to FIG. 2, when the first carrier layer 116 is configured to be the OCA film 120, the first material is converted from the liquid state to a semisolid state or a solid state prior to the positioning. In embodiments, the positioning comprises bonding a first side 136 of the first carrier layer 116 in the semisolid state or the solid state to the first major surface 1of the first transparent substrate 104. In one configuration, the method further comprises forming the hard coating film 128 on a second side 138 of the first carrier layer 116. In another configuration, the method further comprises positioning a second transparent substrate 140 on a second side 138 of the first carrier layer 116.

[0091]Referring again to FIGS. 3 and 4, the positioning can comprise positioning a first side 136 of the first carrier layer 116 in the semisolid state or the solid state over the first major surface 108 of the first transparent substrate 104. Then, the method further comprises forming a second carrier layer 144 on the first major surface 108 of the first transparent substrate 104. In embodiments, the second carrier layer 144 is different than the first carrier layer 116 and comprises second scattering particles 148 dispersed throughout the second carrier layer 144.

[0092]In embodiments, the positioning further comprises positioning the first side 136 of the first carrier layer 116 on the second carrier layer 144 such that the second carrier layer 1 SP23-118PCT is positioned between and contacting the first major surface 108 of the first transparent substrate 104 and the first side 136 of the first carrier layer 116. In embodiments, as shown in FIG. 4, the second carrier layer 144 is formed intermittently between and contacting the first major surface 108 of the first transparent substrate 104 and the first side 136 of the first carrier layer 116.

[0093]In one configuration, the method further comprises forming the hard coating film 128 on a second side 138 of the first carrier layer 116. In another configuration, the method comprises positioning a second transparent substrate 140 on a second side 138 of the first carrier layer 116.

[0094]In embodiments, the method further comprises modulating a concentration of the first scattering particles 132 added to the first material to form discrete volumes of the first material with different concentrations of the first scattering particles 132. Thereafter, the method further comprises selecting one of the discrete volumes of the first material so that first carrier layer 116 has a target concentration of the first scattering particles 132.

[0095] EXAMPLES

[0096]Various embodiments of the present disclosure can be better understood by reference to the following Examples which are offered by way of illustration. The present disclosure is not limited to the Examples given herein.

[0097] Example 1

[0098]TiO2 particles from NanoAmor, Inc. were added to an OCA base material formulation before OCA film fabrication. The TiO2 particles are mixed sufficiently to scatter the light evenly after application. The particle-embedded OCA film has a thickness of 200 pm. The OCA film is then bonded to 2 mm thick Corning IRIS® glass substrate configured as a 200 mm x 200 x square. Another similarly configured IRIS® glass substrate was bonded on the OCA film to provide an edge-lit, transparent light guide plate 100, as shown in FIG. 7. The bonded (laminated) glass LGP 100 is installed in a frame 504 which include light sources 5configured as LED chips to form the lighting device 500. The lighting device 500 is then turned on, as shown in FIG. 9. Angular luminous intensity is measured with spectrophotometer (CS- 1000, Konica-Minolta), as shown in Figure 10.

SP23-118PCT

[0099] Example 2

[0100]Ti02 particles from NanoAmor, Inc. are mixed with optically clear resin (OCR) material which is made of silicon. For gradation lighting, haze of bonded LGP is 95% and transmittance is 55%. A 2 mm thick Corning IRIS® glass substrate configured as a 200 mm x 200 x square was attached to another similarly configured Corning IRIS® glass substrate, as shown in FIG. 11. LED chips were placed at the edge to provide guided light. Since OCR has scattering particles, light from the edge was scattered, thus successfully demonstrating an integrated glass system configured as an edge-lit, transparent LGP 100. Compared with non- particle-embedded OCR sample, as shown in FIG. 12, it is clear that the edge-lit LED light is not scattered. Modulation of particle concentration can control the quantity and mode of light guiding from edge to substrate center.

[0101]The embodiments of the LGP 100 and the lighting device 500 disclosed herein have numerous advantages. Existing LGP configuration may use printing pattern on the substrate or direct laser engraving to give light scattering power. Those patterns or laser engraving marks can be visible, decreasing quality of lighting and making moire when providing transparent lighting. To hide visible patterns, a diffuser plate can be used. However, such diffuser plates make can make LGP translucent. Thus, manufacturers are confronted with a dilemma, provide transparent lighting with visible patterns or provide translucent edge-lit lighting.

[0102]Scattering particles can be used to reduce the issue of visible patters when sized appropriately and used in low concentration. Small scattering particles can scatter light without any visibility/discernibility of the scattering centers. This approach can be realized by coating a scattering particle formulation on a clear substrate. However, wet coating processes may require different types of coating machines, such as slot-die coater, spray coater, inkjet printer, etc.

[0103]To improve processing and reduce manufacturing costs, the LGP 100 disclosed herein embeds scattering particles inside the OCA film and OCR, giving scattering power to clear substrates by attaching particle-embedded OCA film or by inserting particle-embedded OCR between substrates.

[0104] Particle-embedded OCA or OCR can be considered if laminated LGP is required, such as for higher strength or scratch resistance. When fabricating OCA film or formulating OCR mixture, scattering particles (e.g., SiO2, TiO2, ZrO2, SnO2, BaTiO3, and other) can be added to the OCA or OCR base material to provide scattering power. Additional coating or SP23-118PCT patterning on LGP is still possible to give additional function as illustrated by the second carrier layer 144 illustrated in FIGS. 3 and 4.

[0105]While the disclosure has been illustrated and described in detail in the drawings and foregoing description, the same should be considered as illustrative and not restrictive in character. It is understood that only the preferred embodiments have been presented and that all changes, modifications, and further applications that come within the spirit of the disclosure are desired to be protected.

Claims (37)

1. Claims 1. A light guide plate, comprising:
2. 2. The light guide plate of claim 1, wherein the first carrier layer is configured as the OCA film or the OCR and a first side of the first carrier layer is positioned on the first major surface of the first transparent substrate.
3. 3. The light guide plate of claim 1, wherein the first carrier layer is configured as the OCA film and a first side of the first carrier layer is positioned over the first major surface of the first transparent substrate.
4. 4. The light guide plate of claim 3, further comprising: a second carrier layer positioned between and contacting the first transparent substrate and the first side of the first carrier layer; and second scattering particles dispersed throughout the second carrier layer.
5. 5. The light guide plate of claim 4, wherein the second carrier layer is positioned intermittently between and contacting the first transparent substrate and the first side of the first carrier layer.
6. 6. The light guide plate of claim 4 or claim 5, wherein the second carrier layer is different than the first carrier layer.
7. 7. The light guide plate of claim 4 or claim 5, wherein the second carrier layer is a matrix.
8. 8. The light guide plate of claim 4 or claim 5, wherein the second scattering particles comprise BaTiO3, SnO2, SiO2, TiO2, ZrO2, or combinations thereof.
9. 9. The light guide plate of claim 1, further comprising a second transparent substrate positioned on a second side of the first carrier layer, the second side opposite the first side of the first carrier layer.
10. 10. The light guide plate of claim 9, wherein the second transparent substrate comprises a polymeric material or a glass material.
11. 11. The light guide plate of claim 1, wherein the hard coating film is positioned on a second side of the first carrier layer, the second side opposite the first side of the first carrier.
12. 12. The light guide plate of claim 1, wherein the first scattering particles comprise BaTiO3, SnO2, SiO2, TiO2, ZrO2, or combinations thereof.
13. 13. The light guide plate of claim 1, wherein the first carrier layer is configured as the hard coating film positioned on the first major surface of the first transparent substrate.
14. 14. The light guide plate of claim 13, wherein the first scattering particles comprise BaTiO3, SnO2, SiO2, TiO2, ZrO2, or combinations thereof.
15. 15. The light guide plate of claim 13 or claim 14, wherein the hard coating film comprises acrylic polymer and the first scattering particles comprise SiO2.
16. 16. The light guide plate of claim 13 or claim 14, wherein the hard coating film comprises acrylic monomer and the first scattering particles comprise BaTiO3, SnO2, TiO2, ZrO2, or combinations thereof.
17. 17. The light guide plate of claim 1, wherein the first transparent substrate comprises a polymeric material or a glass material.
18. 18. The light guide plate of claim 1, wherein a haze of the light guide plate is in a range of from about 1% to about 5%.
19. 19. The light guide plate of claim 1, wherein an optical transmittance of the light guide plate is greater than about 80% over a length of 500 mm in visible region of the spectrum.
20. 20. A method for manufacturing a light guide plate, comprising: embedding first scattering particles in a first carrier layer; positioning the first carrier layer on or over a first major surface of a first transparent substrate after the embedding; and wherein the first carrier layer is an optically clear adhesive (OCA) film, an optically clear resin (OCR), or a hard coating film that is transparent and exhibits at least H pencil hardness.
21. 21. The method of claim 20, wherein the embedding comprises adding the first scattering particles to a first material of the first carrier layer when the first material is in a liquid state.
22. 22. The method of claim 21, wherein, when the first carrier layer is the OCA film, the first material is converted from the liquid state to a semisolid state or a solid state prior to the positioning.
23. 23. The method of claim 22, wherein the positioning comprises bonding a first side of the first carrier layer in the semisolid state or the solid state to the first major surface of the first transparent substrate.
24. 24. The method of claim 23, further comprising positioning a second transparent substrate on a second side of the first carrier layer, the second side opposite the first side of the first carrier layer.
25. 25. The method of claim 23, further comprising forming the hard coating film on a second side of the first carrier layer, the second side opposite the first side of the first carrier layer.
26. 26. The method of claim 21, wherein, when the first carrier layer is the OCR, the positioning comprises coating the first carrier layer in the liquid state on the first major surface of the first transparent substrate.
27. 27. The method of claim 26, further comprising positioning a second transparent substrate on the first carrier layer, the second side opposite the first side of the first carrier layer.
28. 28. The method of claim 21, wherein, when the first carrier layer is the OCR, the positioning comprises: positioning a second transparent substrate proximate the first transparent substrate, and injecting the first carrier layer in the liquid state between the first transparent substrate and the second transparent substrate.
29. 29. The method of claim 26, further comprising forming the hard coating film on a second side of the first carrier layer, the second side opposite the first side of the first carrier layer.
30. 30. The method of claim 22, wherein the positioning comprises positioning a first side of the first carrier layer in the semisolid state or the solid state over the first major surface of the first transparent substrate.
31. 31. The method of claim 30, further comprising forming a second carrier layer on the first major surface of the first transparent substrate, the second carrier layer different than the first carrier layer and comprising second scattering particles dispersed throughout the second carrier layer.
32. 32. The method of claim 31, wherein the positioning further comprises positioning the first side of the first carrier layer on the second carrier layer such that the second carrier layer is positioned between and contacting the first transparent substrate and the first side of the first carrier layer.
33. 33. The method of claim 32, wherein the second carrier layer is formed intermittently between and contacting the first transparent substrate and the first side of the first carrier layer.
34. 34. The method of claim 33, further comprising positioning a second transparent substrate on a second side of the first carrier layer, the second side opposite the first side of the first carrier layer.
35. 35. The method of claim 33, further comprising forming the hard coating film on a second side of the first carrier layer, the second side opposite the first side of the first carrier layer.
36. 36. The method of claim 21, wherein, when the first carrier layer is the hard coating film, the positioning comprises coating the first carrier layer in the liquid state on the first major surface of the first transparent substrate.
37. 37. The method of claim 21, further comprising: modulating a concentration of the first scattering particles added to the first material to form discrete volumes of the first material with different concentrations of the first scattering particles; and selecting one of the discrete volumes of the first material so that the first carrier layer has a target concentration of the first scattering particles.