WO2019059916A1

WO2019059916A1 - Back light unit and electronic display

Info

Publication number: WO2019059916A1
Application number: PCT/US2017/052851
Authority: WO
Inventors: Shenping Li
Original assignee: Corning Inc
Current assignee: Corning Inc
Priority date: 2017-09-22
Filing date: 2017-09-22
Publication date: 2019-03-28
Anticipated expiration: 2020-03-22

Abstract

A back light unit can include a light guide plate, a waveguide bonded to a major surface of the light guide plate, and a light source facing an edge of the waveguide. The light source can be oriented to provide light from the light source to the edge of the waveguide. In some embodiments, a plurality of waveguides and a plurality of light sources can be provided. In some embodiments, a back light unit can include a first light guide plate and a second light guide plate, with a first plurality of waveguides bonded to the first light guide plate and a second plurality of waveguides bonded to the second light guide plate. In some embodiments, the back light unit can provide local one-dimensional dimming and local two-dimensional dimming. In some embodiments, an electronic display including a back light unit facing a display panel can be provided.

Description

BACK LIGHT UNIT AND ELECTRONIC DISPLAY

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority of U.S. Provisional Application Serial No. 62/379,488 filed on August 25, 2016 the contents of which are relied upon and incorporated herein by reference in their entirety as if fully set forth below.

FIELD

[0001] The present disclosure relates generally to a back light unit, and more particularly, to a back light unit including a light guide plate, a waveguide, and a light source.

BACKGROUND

[0002] It is known to illuminate a display panel of an electronic display with a back light unit. It is also known to illuminate a waveguide with a light source facing an edge of the waveguide.

SUMMARY

[0003] The following presents a simplified summary of the disclosure in order to provide a basic understanding of some exemplary embodiments described in the detailed description.

[0004] In some embodiments, a back light unit can include a light guide plate, a waveguide bonded to a major surface of the light guide plate, and a light source facing an edge of the waveguide. The light source can be oriented to provide light from the light source to the edge of the waveguide.

[0005] In some embodiments, an electronic display can include a back light unit oriented to face a major surface of a display panel.

[0006] In some embodiments, the light source can include an LED.

[0007] In some embodiments, both the light guide plate and the waveguide can include the same material. [0008] In some embodiments, both the light guide plate and the waveguide can include glass.

[0009] In some embodiments, the light guide plate and the waveguide can each include different materials.

[0010] In some embodiments, the light guide plate can include glass and the waveguide can include a polymer material.

[0011] In some embodiments, Van der Waals forces between the waveguide and the light guide plate can bond the waveguide to the light guide plate.

[0012] In some embodiments, the waveguide can be bonded to the light guide plate with a bonding agent.

[0013] In some embodiments, the bonding agent can be transparent to visible light.

[0014] In some embodiments, the waveguide can include a material that directly bonds to the light guide plate without a separate bonding agent.

[0015] In some embodiments, a thickness of the light guide plate can be defined between the major surface of the light guide plate and an opposing major surface of the light guide plate. In some embodiments, a height of a light emitting region of the light source parallel to the thickness of the light guide plate can be greater than the thickness of the light guide plate.

[0016] In some embodiments, a thickness of the waveguide parallel to the thickness of the light guide plate can be defined between opposing major surfaces of the waveguide. In some embodiments, the thickness of the waveguide can be greater than or equal to a difference between the height of the light emitting region of the light source and the thickness of the light guide plate.

[0017] In some embodiments, a width of the waveguide can be defined along the edge of the waveguide perpendicular to the thickness of the light guide plate. In some embodiments, a width of the light emitting region of the light source parallel to the width of the waveguide can be less than or equal to the width of the waveguide.

[0018] In some embodiments, the waveguide can be a slab waveguide. [0019] In some embodiments, the slab waveguide can include a rectangular cross- sectional profile.

[0020] In some embodiments, a back light unit can include a light guide plate, a first plurality of waveguides bonded to a first major surface of the light guide plate, and a plurality of light sources where each light source of the plurality of light sources faces a respective edge of a respective waveguide of the first plurality of waveguides. Each light source of the plurality of light sources can be oriented to provide light from a respective light source of the plurality of light sources to the respective edge of the respective waveguide of the first plurality of waveguides.

[0021] In some embodiments, a thickness of the light guide plate can be defined between the first major surface of the light guide plate and a second major surface of the light guide plate, a width of the light guide plate can be defined along a first edge of the light guide plate perpendicular to the thickness of the light guide plate, and a length of the light guide plate can be defined along a second edge of the light guide plate perpendicular to the first edge of the light guide plate. In some embodiments, each waveguide of the first plurality of waveguides can extend along the length of the light guide plate; and, in some embodiments, each waveguide of the first plurality of waveguides can be spaced a first distance apart from an adjacent waveguide of the first plurality of waveguides along the width of the light guide plate.

[0022] In some embodiments, each light source of the plurality of light sources can be spaced a second distance apart from an adjacent light source of the plurality of light sources along the width of the light guide plate. In some embodiments, the first distance can be less than or equal to the second distance.

[0023] In some embodiments, at least one of air and a material having a refractive index less than or equal to about 1.2 can be provided between adjacent waveguides of the first plurality of waveguides.

[0024] In some embodiments, each light source of the plurality of light sources can be independently illuminable.

[0025] In some embodiments, the back light unit can further include a second plurality of waveguides bonded to the second major surface of the light guide plate. Each waveguide of the second plurality of waveguides can be aligned with a respective waveguide of the first plurality of waveguides. In some embodiments, each waveguide of the second plurality of waveguides can extend along the length of the light guide plate parallel to the respective waveguide of the first plurality of waveguides. In some embodiments, each waveguide of the second plurality of waveguides can be spaced the first distance apart from an adjacent waveguide of the second plurality of waveguides along the width of the light guide plate.

[0026] In some embodiments, each light source of the plurality of light sources can face a respective edge of a respective waveguide of the second plurality of waveguides, and each light source of the plurality of light sources can be further oriented to provide light from a respective light source to the respective edge of the respective waveguide of the second plurality of waveguides.

[0027] In some embodiments, a back light unit can include a first light guide plate, a first plurality of waveguides bonded to a first major surface of the first light guide plate, and a first plurality of light sources. Each light source of the first plurality of light sources can face a respective edge of a respective waveguide of the first plurality of waveguides, and each light source of the first plurality of light sources can be oriented to provide light from a respective light source of the first plurality of light sources to the respective edge of the respective waveguide of the first plurality of waveguides. The back light unit can include a second light guide plate oriented with a first major surface facing a second major surface of the first light guide plate. A second plurality of waveguides can be bonded to the first major surface of the second light guide plate. Each light source of a second plurality of light sources can face a respective edge of a respective waveguide of the second plurality of waveguides, and each light source of the second plurality of light sources can be oriented to provide light from a respective light source of the second plurality of light sources to the respective edge of the respective waveguide of the second plurality of waveguides.

[0028] In some embodiments, each waveguide of the first plurality of waveguides can be perpendicular to each waveguide of the second plurality of waveguides. [0029] In some embodiments, a thickness of the first light guide plate can be defined between the first major surface of the first light guide plate and the second major surface of the first light guide plate, a width of the first light guide plate can be defined along a first edge of the first light guide plate perpendicular to the thickness of the first light guide plate, and a length of the first light guide plate can be defined along a second edge of the first light guide plate perpendicular to the first edge of the first light guide plate. Each waveguide of the first plurality of waveguides can extend along the length of the first light guide plate and each waveguide of the first plurality of waveguides can be spaced a first distance apart from adjacent waveguides of the first plurality of waveguides along the width of the first light guide plate. In some embodiments, a thickness of the second light guide plate parallel to the thickness of the first light guide plate can be defined between the first major surface of the second light guide plate and a second major surface of the second light guide plate, a width of the second light guide plate parallel to the width of the first light guide plate can be defined along a first edge of the second light guide plate perpendicular to the thickness of the second light guide plate, and a length of the second light guide plate can be defined along a second edge of the second light guide plate perpendicular to the first edge of the second light guide plate. Each waveguide of the second plurality of waveguides can extend along the second width of the second light guide plate and each waveguide of the second plurality of waveguides can be spaced a second distance apart from adjacent waveguides of the second plurality of waveguides along the length of the second light guide plate.

[0030] In some embodiments, the first light guide plate can be spaced apart from the second light guide plate, thereby defining a gap between the second major surface of the first light guide plate and the second plurality of waveguides.

[0031] In some embodiments, the gap can include at least one of air and a material having a refractive index less than or equal to about 1.2.

[0032] In some embodiments, each light source of the first plurality of light sources and each light source of the second plurality of light sources can be independently illuminable. [0033] The above embodiments are exemplary and can be provided alone or in any combination with any one or more embodiments provided herein without departing from the scope of the disclosure. Moreover, it is to be understood that both the foregoing general description and the following detailed description present embodiments of the present disclosure, and are intended to provide an overview or framework for understanding the nature and character of the embodiments as they are described and claimed. The accompanying drawings are included to provide a further understanding of the embodiments, 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

[0034] These and other features, embodiments, and advantages of the present disclosure can be further understood when read with reference to the accompanying drawings:

[0035] FIG. 1 illustrates a schematic side view of an exemplary electronic display including a back light unit in accordance with embodiments disclosed herein;

[0036] FIG. 2 shows a top view of the exemplary electronic display of FIG. 1.

[0037] FIG. 3 shows a schematic view of a region of the back light unit identified by numeral 3 of FIG. 1 including a waveguide bonded to a light guide plate;

[0038] FIG. 4 illustrates a schematic side view of an exemplary back light unit including a light guide plate and a plurality of waveguides in accordance with embodiments disclosed herein;

[0039] FIG. 5 shows an alternate side view of the exemplary back light unit of FIG. 4 along line 5-5 of FIG. 4;

[0040] FIG. 6 illustrates a schematic side view of an exemplary back light unit including a light guide plate, a first plurality of waveguides, and a second plurality of waveguides in accordance with embodiments disclosed herein;

[0041] FIG. 7 shows an alternate side view of the exemplary back light unit of FIG. 6 along line 7-7 of FIG. 6; [0042] FIG. 8 illustrates a schematic side view of an exemplary back light unit including a first light guide plate, a first plurality of waveguides, a second light guide plate, and a second plurality of waveguides in accordance with embodiments disclosed herein; and

[0043] FIG. 9 shows an alternate side view of the exemplary back light unit of FIG. 8 along line 9-9 of FIG. 8.

DETAILED DESCRIPTION

[0044] Features will now be described more fully hereinafter with reference to the accompanying drawings in which exemplary embodiments of the disclosure are shown. Whenever possible, the same reference numerals are 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.

[0045] FIG. 1 illustrates an exemplary electronic display 100 in accordance with embodiments disclosed herein. In some embodiments, the electronic display 100 can include a back light unit 120 oriented to face a major surface of a display panel 110. For example, the display panel 110 can include a first major surface 111 opposite a second major surface 112, and the back light unit 120 can be oriented to face the second major surface 112 of the display panel 110. In some embodiments, the first major surface 111 of the display panel 110 can face outward away from the back light unit 120, and the back light unit 120 can illuminate the display panel 110 by providing light from the back light unit 120 to the second major surface 112 of the display panel 110. In some embodiments, the electronic display 100 can be employed as a computer monitor, television monitor, portable display for a cellular phone, tablet, etc., and any other display where the display panel 110 can provide an electronic image (e.g., text, picture, video, etc.) and where the back light unit 120 can illuminate the display panel 110 and the electronic image. In some embodiments, the display panel 110 can include an LCD panel oriented to produce the electronic image which, when illuminated from behind by the back light unit 120, can then be viewed by a user facing the first major surface 111 of the display panel 110.

[0046] In some embodiments, the electronic display 100 can be positioned within a housing (not shown) to, for example, protect the electronic display 100 and provide a structure by which the electronic display 100 can be mounted, held, and otherwise touched by a user or environment in which the electronic display 100 may be employed. In some embodiments, the electronic display 100 can include one or more optical components (e.g., reflectors, filters, etc.) and one or more additional electronic components (e.g., transducers, circuits, receivers, transmitters, power supplies, batteries, etc.) integrated with and electrically connected to the electronic display 100 to, for example, enable a user to interact with and control one or more features of the electronic display 100. Accordingly, it is to be understood that, unless otherwise noted, the features of the electronic display 100 disclosed herein can be employed in a variety of applications including, but not limited to, the particular applications provided herein as exemplary embodiments as well as other applications not explicitly disclosed.

[0047] In some embodiments, the back light unit 120 can include a light guide plate 130 and a waveguide 140 bonded to a major surface of the light guide plate 130. For example, in some embodiments, the light guide plate 130 can include a first major surface 131 opposite a second major surface 132, and the waveguide 140 can include a first major surface 141 opposite a second major surface 142. In some embodiments, the first major surface 141 or the second major surface 142 of the waveguide 140 can be bonded to the first major surface 131 or the second major surface 132 of the light guide plate 130. For example, as shown, in some embodiments, the second major surface 142 of the waveguide 140 can be bonded to the first major surface 131 of the light guide plate 130 at an interface 150 between the waveguide 140 and the light guide plate 130. In some embodiments, the back light unit 120 can be oriented with the waveguide 140 positioned between the light guide plate 130 and the display panel 110. For example, the first major surface 141 of the waveguide 140 can face the second major surface 112 of the display panel 110, in some embodiments. Additionally, in some embodiments (not shown), the back light unit 120 can be oriented with the light guide plate 130 positioned between the waveguide 140 and the display panel 110. For example, although not shown, the second major surface 132 of the light guide plate 130 can face the second major surface 112 of the display panel 110, in some embodiments.

[0048] In some embodiments, the first major surface 131 of the light guide plate 130 can be parallel to the second major surface 132 of the light guide plate 130; however, in some embodiments, the first major surface 131 can be oriented at a non-zero angle relative to the second major surface 132. Similarly, in some embodiments, the first major surface 141 of the waveguide 140 can be parallel to the second major surface 142 of the waveguide 140; however, in some embodiments, the first major surface 141 can be oriented at a non-zero angle relative to the second major surface 142. In some embodiments, any one or more of the first major surface 131 and the second major surface 132 of the light guide plate 130, and the first major surface 141 and the second major surface 142 of the waveguide 140 can be parallel to each other; however, in some embodiments, any one or more of the first major surface 131 and the second major surface 132 of the light guide plate 130, and the first major surface 141 and the second major surface 142 of the waveguide 140 can be oriented at a non-zero angle relative to each other. Additionally, in some embodiments, any one or more of the first major surface 131 and the second major surface 132 of the light guide plate 130, and the first major surface 141 and the second major surface 142 of the waveguide 140 can be planar; however, in some embodiments, any one or more of the first major surface 131 and the second major surface 132 of the light guide plate 130, and the first major surface 141 and the second major surface 142 of the waveguide 140 can be non-planar (e.g., curved).

[0049] As shown in FIG. 2, (with the display panel 110 of the electronic display 100 removed for clarity), in some embodiments, the back light unit 120 can include a light source 125 facing a first edge 146 of the waveguide 140. In some embodiments, the light source 125 can include a light emitting diode (LED), a light bulb, and/or one or more optical fibers. In some embodiments, the light source 125 can be oriented to provide light from the light source 125 to the first edge 146 of the waveguide 140. For example, in some embodiments, light from the light source 125 can travel along a path that is perpendicular to a face of the first edge 146 of the waveguide 140. In some embodiments, a light emitting region of the light source 125 can be optically coupled to the first edge 146 of the waveguide 140. In some embodiments, the light emitting region of the light source 125 can be optically coupled to the first edge 146 of the waveguide 140 by being positioned in physical contact with the first edge 146. In some embodiments, the light emitting region of the light source 125 can be spaced a distance from the first edge 146. Additionally, in some embodiments, an optical medium (e.g., transparent adhesive, optical filter, optical coupler, etc.) can be positioned between the light emitting region of the light source 125 and the first edge 146 of the waveguide 140 to optically couple the light emitting region of the light source 125 to the first edge 146 of the waveguide 140. Optically coupling the light emitting region of the light source 125 to the first edge 146 of the waveguide 140 can illuminate the waveguide 140 based on the light from the light source 125 provided to the first edge 146 of the waveguide 140. In some embodiments, illuminating an object (e.g., the waveguide 140) based on light provided (e.g., from the light source 125) to an edge of the object (e.g., the first edge 146 of the waveguide 140) can be known as "edge-lighting."

[0050] For example, in some embodiments, based on "edge-lighting," light provided from the light emitting region of the light source 125 to the first edge 146 of the waveguide 140 can propagate along the waveguide 140 in a direction away from the first edge 146 to travel through the waveguide 140 between a second edge 147 and a fourth edge 149 toward a third edge 148 of the waveguide 140 opposite the first edge 146. The second edge 147 and the fourth edge 149 of the waveguide 140 can extend between the first edge 146 and the third edge 148, and the light can travel from the first edge 146 toward the third edge 148 while traveling between the second edge 147 and the fourth edge 149. In some embodiments, a distance between the first edge 146 and the third edge 148 along at least one of the second edge 147 and the fourth edge 149 can define a length 145 of the waveguide 140. In some embodiments, light provided from the light emitting region of the light source 125 to the first edge 146 of the waveguide 140 can propagate along the length 145 of the waveguide 140 from the first edge 146 to the third edge 148 illuminating the waveguide 140 within the boundary of the first edge 146, the second edge 147, the third edge 148, and the fourth edge 149. [0051] In some embodiments, the first edge 146 of the waveguide 140 can be parallel to the third edge 148 of the waveguide 140; however, in some embodiments, the first edge 146 can be oriented at a non-zero angle relative to the third edge 148. Likewise, in some embodiments, the second edge 147 of the waveguide 140 can be parallel to the fourth edge 149 of the waveguide 140; however, in some embodiments, the second edge 147 can be oriented at a non-zero angle relative to the fourth edge 149. In some embodiments, the first edge 146 of the waveguide 140 can be perpendicular to at least one of the second edge 147 and the fourth edge 149; however, in some embodiments, the first edge 146 can be oriented at other angles relative to at least one of the second edge 147 and the fourth edge 149. Likewise, in some embodiments, the third edge 148 can be perpendicular to at least one of the second edge 147 and the fourth edge 149; however, in some embodiments, the third edge 148 can be oriented at other angles relative to at least one of the second edge 147 and the fourth edge 149. In some embodiments, any one or more of the first edge 146, the second edge 147, the third edge 148, and the fourth edge 149 of the waveguide 140 can be oriented at an angle relative to each other. Additionally, in some embodiments, any one or more of the first edge 146, the second edge 147, the third edge 148, and the fourth edge 149 can be planar; however, in some embodiments, any one or more of the first edge 146, the second edge 147, the third edge 148, and the fourth edge 149 can be non-planar (e.g., curved).

[0052] "Edge-lighting" of the waveguide 140 can provide a back light unit 120 having smaller dimensions (e.g., a thinner profile) and a back light unit 120 of less weight than, for example, a back light unit 120 that is illuminated with light sources positioned behind the unit (not shown). For example, light sources positioned behind (e.g., facing the second major surface 132 of the light guide plate 130 of FIG. 1) can illuminate the back light unit 120. However, in some embodiments, lighting the back light unit 120 with light sources positioned behind the back light unit 120 may require more light sources to provide a same or similar illumination of the back light unit 120 as compared to the number of light sources provided when the back light unit 120 is illuminated by "edge-lighting" of the waveguide 140. Similarly, in some embodiments, lighting the back light unit 120 with light sources positioned behind the back light unit 120 may provide a comparatively thicker back light unit 120 relative to a thickness of a back light unit 120 illuminated by "edge-lighting" of the waveguide 140. Accordingly, in some embodiments, as trends toward smaller, lighter, and thinner electronic displays may be pursued, the "edge-lit" back light unit 120 of the present disclosure can provide several advantages over back light units illuminated, for example, by light sources positioned behind the back light unit 120.

[0053] Turning back to FIG. 1, in some embodiments, a thickness 133 of the light guide plate 130 can be defined between the first major surface 131 and the second major surface 132 of the light guide plate 130. In some embodiments, a thickness 143 of the waveguide 140 parallel to the thickness 133 of the light guide plate 130 can be defined between the first major surface 141 and the second major surface 142 of the waveguide 140. In some embodiments, a height 123 of a light emitting region of the light source 125 parallel to at least one of the thickness 133 of the light guide plate 130 and the thickness 143 of the waveguide 140 can be greater than the thickness 133 of the light guide plate 130. In some embodiments, the light emitting region of the light source 125 can correspond to a region of the light source 125 from which light is provided. For example, in some embodiments, the light source 125 may include a casing (not shown) that can house electrical components of the light source 125. In some embodiments, the light emitting region of the light source 125 can exclude the features and dimensions of the casing and electrical components and instead may correspond only to the region of the light source 125 from which light is provided. Therefore, unless otherwise noted, dimensions of the light source 125, including the height 123 of the light source 125 and the width 124 of the light source 125, are intended to refer to a corresponding dimension of the light emitting region of the light source 125 from which light is provided and not to a dimension of other non-light emitting features of the light source 125. Moreover, in some embodiments, the light source 125 can include an on/off control where the light source 125 provides light (e.g., illuminates) when an electrical signal is provided to the light source 125 and where the light source 125 does not provide light (e.g., does not illuminate) when the electrical signal is not provided to the light source 125. In some embodiments, an illumination intensity of the light source 125 can be controlled by, for example, varying an electrical signal provided to the light source 125.

[0054] Providing a height 123 of a light emitting region of the light source 125 greater than the thickness 133 of the light guide plate 130 can provide, for example when the light emitting region of the light source 125 is optically coupled to the first edge 146 of the waveguide 140, that light illuminates at least a portion of the first edge 146 of the waveguide 140. Conversely, for example, if the height 123 of the light emitting region of the light source 125 was to be less than or equal to the thickness 133 of the light guide plate 130, in some embodiments, when the light emitting region of the light source 125 is optically coupled to the first edge 146 of the waveguide 140, light may illuminate a first edge 136 of the light guide plate 130 and not the first edge 146 of the waveguide 140. By ensuring that the first edge 146 of the waveguide 140 is illuminated by the light from the light emitting region of the light source 125, proper edge lighting of the waveguide 140 can be achieved. In some embodiments, the waveguide 140 can be a slab waveguide 140 where the first major surface 141 and the second major surface 142 of the waveguide 140 are planar and parallel to each other. In some embodiments, the slab waveguide 140 can include a rectangular cross-sectional profile taken perpendicular to the first major surface 141 of the waveguide 140, where the first edge 146 of the waveguide 140 can include a rectangular profile projected along the length 145 of the waveguide 140.

[0055] Additionally, in some embodiments, the thickness 143 of the waveguide 140 can be greater than or equal to a difference between the height 123 of the light emitting region of the light source 125 and the thickness 133 of the light guide plate 130. By providing a thickness 143 of the waveguide 140 greater than or equal to a difference between the height 123 of the light emitting region of the light source 125 and the thickness 133 of the light guide plate 130, the light emitting region of the light source 125 can be optically coupled to the first edge 146 of the waveguide 140 with light from the light emitting region of the light source 125 illuminating the first edge 146 of the waveguide 140 without illuminating other nearby components. In some embodiments, a thickness 143 of the waveguide 140 greater than or equal to a difference between the height 123 of the light emitting region of the light source 125 and the thickness 133 of the light guide plate 130 can provide better coupling efficiency between the light emitting region of the light source 125 and the first edge 146 of the waveguide 140 as compared to, for example, coupling efficiency between the light emitting region of the light source 125 and the first edge 146 of the waveguide 140 where the thickness 143 of the waveguide 140 is less than a difference between the height 123 of the light emitting region of the light source 125 and the thickness 133 of the light guide plate 130. Accordingly, in some embodiments, providing better coupling efficiency between the light emitting region of the light source 125 and the first edge 146 of the waveguide 140 can improve the illumination characteristics of the back light unit 120, reduce at least one of the relative power, size, and intensity of the light source 125 and thus the cost and/or electrical consumption of the light source 125, and provide additional optical advantages to the back light unit 120 and the electronic display 100.

[0056] A shown in FIG. 2, in some embodiments, a width 144 of the waveguide 140 can be defined along at least one of the first edge 146 and the third edge 148 of the waveguide 140 perpendicular to at least one of the thickness 133 of the light guide plate 130 and the thickness 143 of the waveguide 140. In some embodiments, the width 144 of the waveguide 140 can be defined between the second edge 147 and the fourth edge 149 of the waveguide 140. Additionally, in some embodiments, the width 144 of the waveguide 140 can be constant along the length 145 of the waveguide 140; however, in some embodiments, the width 144 of the waveguide 140 can vary along the length 145 of the waveguide 140. Likewise, in some embodiments, the length 145 of the waveguide 140 can be constant along the width 144 of the waveguide 140; however, in some embodiments, the length 145 of the waveguide 140 can vary along the width 144 of the waveguide 140. In some embodiments, a width 134 of the light guide plate 130 can be defined along at least one of the first edge 136 and the third edge 138 of the light guide plate 130 perpendicular to at least one of the thickness 133 of the light guide plate 130 and the thickness 143 of the waveguide 140. In some embodiments, the width 134 of the light guide plate 130 can be defined between the second edge 137 and the fourth edge 139 of the light guide plate 130. Additionally, in some embodiments, the width 134 of the light guide plate 130 can be constant along the length 135 of the light guide plate 130; however, in some embodiments, the width 134 of the light guide plate 130 can vary along the length 135 of the light guide plate 130. Likewise, in some embodiments, the length 135 of the light guide plate 130 can be constant along the width 134 of the light guide plate 130; however, in some embodiments, the length 135 of the light guide plate 130 can vary along the width 134 of the light guide plate 130.

[0057] In some embodiments, a width 124 of the light emitting region of the light source 125 parallel to at least one of the width 144 of the waveguide 140 and the width 134 of the light guide plate 130 can be less than or equal to the width 144 of the waveguide 140. By providing a width 124 of the light emitting region of the light source 125 less than or equal to the width 144 of the waveguide 140, the light emitting region of the light source 125 can be coupled to the first edge 146 of the waveguide 140 with light from the light emitting region of the light source 125 illuminating the first edge 146 of the waveguide 140, without illuminating other nearby components. In some embodiments, a width 124 of the waveguide 140 less than or equal to the width 144 of the waveguide 140 can provide better coupling efficiency between the light emitting region of the light source 125 and the first edge 146 of the waveguide 140 as compared to, for example, coupling efficiency between the light emitting region of the light source 125 and the first edge 146 of the waveguide 140 where the width 124 of the light emitting region of the light source 125 is greater than the width 144 of the waveguide 140. Accordingly, in some embodiments, providing better coupling efficiency between the light emitting region of the light source 125 and the first edge 146 of the waveguide 140 can improve the illumination characteristics of the back light unit 120, reduce at least one of the relative power, size, and intensity of the light source 125, and provide additional optical advantages to the back light unit 120 and the electronic display 100.

[0058] Moreover, although illustrated with respect to the first edge 146 of the waveguide 140, it is to be understood that in some embodiments (not shown), the light source 125 can face the third edge 148 of the waveguide 140, and the light source 125 can be oriented to provide light from the light source 125 to the third edge 148 of the waveguide 140. Additionally, in some embodiments, one light source (e.g., light source 125) can face the first edge 146 of the waveguide 140 and another light source (not shown) can face the third edge 148 of the waveguide 140. The one light source 125 can be oriented to provide light from the one light source 125 to the first edge 146 of the waveguide 140, and the other light source can be oriented to provide light from the other light source to the third edge 148 of the waveguide 140. In some embodiments, light provided from the light emitting region of the other light source to the third edge 148 of the waveguide 140 can propagate along the waveguide 140 in a direction away from the third edge 148 to travel through the waveguide 140 between the second edge 147 and the fourth edge 149. The light can travel toward the first edge 146 opposite the third edge 148. In some embodiments, light provided from the light emitting region of the other light source to the third edge 148 of the waveguide 140 can propagate along the length 145 of the waveguide 140 from the third edge 148 to the first edge 146 illuminating the waveguide 140 within the boundary of the first edge 146, the second edge 147, the third edge 148, and the fourth edge 149. Accordingly, in some embodiments, the waveguide 140 can be illuminated within the boundary of the first edge 146, the second edge 147, the third edge 148, and the fourth edge 149 by at least one of a light source 125 providing light from the light source 125 to the first edge 146 and another light source providing light from the other light source to the third edge 148.

[0059] It is to be understood that illumination of the waveguide 140 by the light source 125 facing the first edge 146 of the waveguide 140 is the primary manner by which the back light unit 120 can be illuminated. For example, as discussed more fully below, illuminating the waveguide 140 of the back light unit 120 can, in some embodiments, provide local one-dimensional dimming and local two-dimensional dimming of the back light unit 120. However, in some embodiments, in addition to facing the first edge 146 of the waveguide 140 and providing light from the light emitting region of the light source 125 to the first edge 146, the light source 125 can also face a first edge 136 of the light guide plate 130. For example, if the light emitting region of the light source 125 includes a larger dimension than a corresponding dimension of the first edge 146 of the waveguide 140, the light emitting region of the light source 125 may also provide light from the light source 125 to the first edge 136 of the light guide plate 130. Likewise, in some embodiments, the light emitting region of the light source 125 may be optically coupled to at least a portion of the first edge 146 of the waveguide 140 and optically coupled to at least a portion of the first edge 136 of the light guide plate 130.

[0060] Optically coupling the light emitting region of the light source 125 to the first edge 146 of the waveguide 140 and the first edge 136 of the light guide plate 130 can provide an advantage, in some embodiments, where a size of the light source 125 can be larger than, for example, the size of a light source 125 that is sized to be optically coupled to only the first edge 146 of the waveguide 140 and not the first edge 136 of the light guide plate 130. That is, for a given total dimension of the back light unit 120 (e.g., the sum of the thickness 133 of the light guide plate 130 and the thickness 143 of the waveguide 140) a light source 125 of larger size (e.g., a height 123 of the light emitting region of the light source 125 less than or equal to the given total dimension) can be employed if the light emitting region of the light source 125 is optically coupled to both the first edge 146 of the waveguide 140 and the first edge 136 of the light guide plate 130. Accordingly, for the given total dimension of the back light unit 120, a light source 125 of smaller size (e.g., a height 123 of the light emitting region of the light source 125 less than or equal to the thickness 143 of the waveguide 140) would be employed if the light emitting region of the light source 125 were to be optically coupled to only the first edge 146 of the waveguide 140 and not the first edge 136 of the light guide plate 130. Despite this advantage, it is to be understood, that in some embodiments, the light emitting region of the light source 125 can be optically coupled to only the first edge 146 of the waveguide 140 and not to the first edge 136 of the light guide plate 130 without departing from the scope of the disclosure.

[0061] In some embodiments, the size of the light source 125 may be based, at least in part, on any one or more of the size of light source 125 available from a light source manufacturer, the illumination output and power consumption of the light source 125, the heat dissipation characteristics of the light source 125, etc. Thus, in some embodiments, where a smaller light source 125 may be desired to provide a smaller back light unit 120, a larger light source 125 may, nonetheless, be employed because of other considerations. By optically coupling the light emitting region of the light source 125 to both the first edge 146 of the waveguide 140 and the first edge 136 of the light guide plate 130, the total dimension of the back light unit 120 can be reduced and the larger light source 125 can be employed without having to employ the smaller light source 125 and without having to increase the thickness 143 of the waveguide 140. At least one of employing the smaller light source 125 and increasing the thickness 143 of the waveguide 140 may otherwise be required if the light emitting region of the light source 125 was to be optically coupled only to the first edge 146 of the waveguide 140 and not to the first edge 136 of the light guide plate 130.

[0062] Accordingly, in some embodiments, the light source 125 can be oriented to provide light from the light source 125 to the first edge 136 of the light guide plate 130. For example, in some embodiments, a light emitting region of the light source 125 can be optically coupled to the first edge 136 of the light guide plate 130. In some embodiments, the light emitting region of the light source 125 can be optically coupled to the first edge 136 by being positioned in physical contact with the first edge 136 of the light guide plate 130. In some embodiments, the light emitting region of the light source 125 can be spaced a distance from the first edge 136. Additionally, in some embodiments, an optical medium (e.g., transparent adhesive, optical filter, optical coupler etc.) can be positioned between the light emitting region of the light source 125 and the first edge 136 of the light guide plate 130 to optically couple the light emitting region of the light source 125 to the first edge 136 of the light guide plate 130.

[0063] In some embodiments, light provided from the light emitting region of the light source 125 to the first edge 136 of the light guide plate 130 can propagate along the light guide plate 130 in a direction away from the first edge 136 to travel through the light guide plate 130 between a second edge 137 and a fourth edge 139 of the light guide plate 130 toward a third edge 138 opposite the first edge 136. The second edge 137 and the fourth edge 139 can extend between the first edge 136 and the third edge 138, and the light can travel from the first edge 136 toward the third edge 138 while traveling between the second edge 137 and the fourth edge 139. In some embodiments, a distance between the first edge 136 and the third edge 138 along at least one of the second edge 137 and the fourth edge 139 can define a length 135 of the light guide plate 130. In some embodiments, light provided from the light emitting region of the light source 125 to the first edge 136 of the light guide plate 130 can propagate along the length 135 of the light guide plate 130 from the first edge 136 to the third edge 138 illuminating the light guide plate 130 within the boundary of the first edge 136, the second edge 137, the third edge 138, and the fourth edge 139. In some embodiments, an intensity of the light on the light guide plate 130 may be greater at a location relative to the width 134 of the light guide plate 130 that is closer to the light source 125 than at a location relative to the width 134 that is, for example, farther away from the light source 125. For example, in some embodiments, an intensity of light may decrease across the width 134 of the light guide plate 130 from a greater intensity at the light source 125 to a lower intensity away from the light source 125 relative to the width 134 of the light guide plate 130 as light propagates from the first edge 136 across the length 135 of the light guide plate 130 to the third edge 138.

[0064] In some embodiments, the first edge 136 of the light guide plate 130 can be parallel to the third edge 138 of the light guide plate 130; however, in some embodiments, the first edge 136 can be oriented at a non-zero angle relative to the third edge 138. Likewise, in some embodiments, the second edge 137 of the light guide plate 130 can be parallel to the fourth edge 139 of the light guide plate 130; however, in some embodiments, the second edge 137 can be oriented at a non-zero angle relative to the fourth edge 139. In some embodiments, the first edge 136 of the light guide plate 130 can be perpendicular to at least one of the second edge 137 and the fourth edge 139 of the light guide plate 130; however, in some embodiments, the first edge 136 can be oriented at other angles relative to at least one of the second edge 137 and the fourth edge 139. In some embodiments, the third edge 138 of the light guide plate 130 can be perpendicular to at least one of the second edge 137 and the fourth edge 139 of the light guide plate 130; however, in some embodiments, the third edge 138 can be oriented at other angles relative to at least one of the second edge 137 and the fourth edge 139. In some embodiments, any one or more of the first edge 136, the second edge 137, the third edge 138, and the fourth edge 139 of the light guide plate 130 can be oriented at an angle relative to each other. In some embodiments, any one or more of the first edge 136, the second edge 137, the third edge 138, and the fourth edge 139 of the light guide plate 130 can be planar; however, in some embodiments, any one or more of the first edge 136, the second edge 137, the third edge 138, and the fourth edge 139 can be non-planar (e.g., curved).

[0065] In some embodiments, any one or more of the first edge 136, the second edge 137, the third edge 138, and the fourth edge 139 of the light guide plate 130, and the first edge 146, the second edge 147, the third edge 148, and the fourth edge 149 of the waveguide 140 can be oriented at an angle relative to each other. Additionally, in some embodiments, the length 135 of the light guide plate 130 can be equal to the length 145 of the waveguide 140; however, in some embodiments, the length 135 of the light guide plate 130 can be greater than or less than the length 145 of the waveguide 140. In some embodiments, the first edge 146 of the waveguide 140 can be aligned (e.g., flush) with the first edge 136 of the light guide plate 130 and the third edge 148 of the waveguide 140 can be aligned with the third edge 138 of the light guide plate 130; however, in some embodiments, at least one of the first edge 146 and the third edge 148 of the waveguide 140 can be offset relative to the corresponding first edge 136 and third edge 138 of the light guide plate 130. Likewise, in some embodiments, at least one of the second edge 147 and the fourth edge 149 of the waveguide 140 can be aligned with the corresponding second edge 137 and the fourth edge 139 of the light guide plate 130; however, in some embodiments, at least one of the second edge 147 and the fourth edge 149 of the waveguide 140 can be offset relative to the corresponding second edge 137 and the fourth edge 139 of the light guide plate 130. In some embodiments, aligning any one or more edges of the waveguide 140 with a corresponding one or more edges of the light guide plate 130 can provide a back light unit 120 having a dimensionally uniform footprint that may be desirable in some applications in which the back light unit 120 may be employed. Alternatively, in some embodiments, offsetting any one or more edges of the waveguide 140 relative to a corresponding one or more edges of the light guide plate 130 can provide a back light unit 120 having a dimensionally non-uniform footprint that may be desirable in some applications in which the back light unit 120 may be employed.

[0066] FIG. 3 illustrates a portion of the back light unit 120 of the electronic display 100 identified with numeral 3 in FIG. 1 including the interface 150 between the light guide plate 130 and the waveguide 140. For example, in some embodiments, the interface 150 can include a bonding agent 300 and the waveguide 140 can be bonded to the light guide plate 130 with the bonding agent 300. In some embodiments, a separate bonding agent 300 can be applied and placed in contact with the second major surface 142 of the waveguide 140 and the first major surface 131 of the light guide plate 130 to bond the waveguide 140 to the light guide plate 130. In some embodiments, the bonding agent 300 can be transparent to visible light. For purposes of this disclosure, visible light is considered light with wavelengths from 400 nanometers to 700 nanometers, and an element (e.g., bonding agent 300) is considered "transparent" if greater than or equal to 85% of visible light can pass through the element. In some embodiments, a bonding agent 300 that is transparent to visible light can allow light from the light source 125 that has illuminated the waveguide 140 to propagate from the waveguide 140 through the bonding agent 300 to the light guide plate 130. In comparison, if the bonding agent 300 was opaque to visible light, in some embodiments, the bonding agent 300 may at least one of reduce and block light from the light source 125 that has illuminated the waveguide 140 from propagating from the waveguide 140 to the light guide plate 130. Accordingly, in some embodiments, the transparent bonding agent 300 can bond the waveguide 140 and the light guide plate 130 together without affecting the transmission of visible light between the waveguide 140 and the light guide plate 130 and without degrading the optical characteristics of the back light unit 120.

[0067] Additionally, in some embodiments, Van der Waals forces between the waveguide 140 and the light guide plate 130 can act either alone or in combination with other bonding techniques to bond the waveguide 140 to the light guide plate 130. For example, the second major surface 142 of the waveguide 140 can be positioned in contact with the first major surface 131 of the light guide plate 130 and the interface 150 can include Van der Waals forces between the second major surface 142 and the first major surface 131 which can bond the waveguide 140 to the light guide plate 130 without another bonding technique (e.g., without a bonding agent 300). Positioning the second major surface 142 of the waveguide 140 in contact with the first major surface 131 of the light guide plate 130 can allow light from the light source 125 that has illuminated the waveguide 140 to propagate from the waveguide 140 through the interface 150 to the light guide plate 130. In comparison, if the second major surface 142 of the waveguide 140 was spaced apart from and, therefore, not in contact with the first major surface 131 of the light guide plate 130, in some embodiments, light from the light source 125 that has illuminated the waveguide 140 may not propagate from the waveguide 140 to the light guide plate 130. Accordingly, in some embodiments, Van der Waals forces between the waveguide 140 and the light guide plate 130 can bond the waveguide 140 and the light guide plate 130 together without affecting the transmission of visible light between the waveguide 140 and the light guide plate 130 and without degrading the optical characteristics of the back light unit 120.

[0068] Bonding the waveguide 140 to the light guide plate 130 can provide several advantages. For example, if the waveguide 140 is not bonded to the light guide plate 130 (e.g., if the waveguide 140 is spaced apart from the light guide plate 130 or provided without a bonding agent 300), a structure (e.g., a frame) may be employed to hold at least one of the waveguide 140 and the light guide plate 130 in a position relative to each other to provide the back light unit 120 of the electronic display 100. Accordingly, by bonding the waveguide 140 to the light guide plate 130, an additional structure need not be employed and the weight, complexity, size, cost, etc. of the back light unit 120 can therefore be reduced. Additionally, in some embodiments, bonding the waveguide 140 to the light guide plate 130 can provide a back light unit 120 that can include multiple materials. For example, as compared to a back light unit 120 that is a singular structure including one material, in some embodiments, the back light unit 120 of the present disclosure can include a plurality of structures including one or more materials. In some embodiments, one or more materials which the back light unit 120 includes can be selected based at least in part on, cost of the material, optical characteristics of the material, physical characteristics of the material, etc. Accordingly, by providing a back light unit 120 that can include different materials selected to provide different features, the back light unit 120 can, in some embodiments, achieve advantages that cannot be obtained by a back light unit 120 including, for example, a single material or manufactured as a single structure. [0069] In some embodiments, the waveguide 140 can include a material that directly bonds to the light guide plate 130 without a separate bonding agent (e.g., without bonding agent 300). Accordingly, in some embodiments, properties of the material which the waveguide 140 includes can provide bonding between the waveguide 140 and the light guide plate 130. For example, in some embodiments, the light guide plate 130 can include glass and the waveguide 140 can include a polymer material. In some embodiments, the polymer material which the waveguide 140 can include can directly bond to the glass of the light guide plate 130 without a separate bonding agent (e.g., without bonding agent 300). In some embodiments, both the light guide plate 130 and the waveguide 140 can include the same material. In some embodiments, the light guide plate 130 and the waveguide 140 can each include different materials. In some embodiments, the back light unit 120 can be manufactured by a molding process or an extrusion process that produces the back light unit 120 including at least one of the light guide plate 130 and the waveguide 140. In some embodiments, a solid piece of material may be machined (e.g., mechanically machined, etched, laser scribed, etc.) to provide the back light unit 120 including the light guide plate 130 and the waveguide 140 as an integral component. In some embodiments, the solid piece of material can include one or more different materials bonded together and then machined to provide the back light unit 120 including the light guide plate 130 and the waveguide 140 as an integral component including the one or more different materials. In some embodiments, the light guide plate 130 and the waveguide 140 can be manufactured separately and then bonded together to provide the back light unit 120.

[0070] In some embodiments, at least one of the light guide plate 130 and the waveguide 140 can include glass. In some embodiments, the glass can be formed from a molten material. For example, glass sheets are commonly fabricated by flowing molten glass to a forming body whereby a glass ribbon may be formed by a variety of ribbon forming processes including, float, slot draw, down-draw, fusion down-draw, up-draw, press roll or any other forming processes. The glass ribbon from any of these processes may then be subsequently divided to provide one or more glass sheets suitable for further processing into a desired application, including but not limited to, a display application. For example, in some embodiments, at least one of the light guide plate 130 and the waveguide 140 can be manufactured according to any one or more of a ribbon forming process. In some embodiments, at least one of the light guide plate 130 and the waveguide 140 can include a variety of compositions including but not limited to glass (e.g., soda-lime glass, borosilicate glass, alumino-borosilicate glass, an alkali-containing glass, or an alkali-free glass), ceramic, glass-ceramic, or any combination thereof.

[0071] In some embodiments, an amount of light confined in the waveguide 140 can be based at least in part on a refractive index of the material which the waveguide 140 includes. For example, a waveguide 140 with a higher refractive index relative to the light guide plate 130 can correspond to more light being confined in the waveguide 140 than the amount of light confined in the waveguide 140 for a waveguide 140 with a lower refractive index relative to the light guide plate 130. Additionally, in some embodiments, more light can be confined in the waveguide 140 when the refractive index of the waveguide 140 is smaller than the refractive index of the light guide plate 130. In some embodiments, confining more light in the waveguide 140 can improve the optical and illumination properties of the waveguide 140 (as compared to confining less light in the waveguide 140) and can therefore provide a comparably better back light unit 120 for the electronic display 100. Accordingly, in some embodiments, a difference between the refractive index of the waveguide 140 and the refractive index of the light guide plate 130 can be, for example, from 0 to less than or equal to about 0.6, from 0 to less than or equal to about 0.4, and from 0 to less than or equal to about 0.2.

[0072] In some embodiments, the back light unit 120 can include one (e.g., a single) waveguide 140 bonded to one (e.g., a single) light guide plate 130. Additionally, in some embodiments, the back light unit 120 can include one or more light guide plates 130 and one or more waveguides 140. Moreover, features of the electronic display 100 can be included alone or in combination with features of the exemplary embodiments disclosed herein without departing from the scope of the disclosure irrespective of the number of light guide plates 130 and the number of waveguides 140 included in the plurality of waveguides 240 disclosed in the embodiment with respect to which features are described. Accordingly, it is to be understood, unless otherwise noted, that any one or more features disclosed herein can be provided alone or in combination with any additional one or more features disclosed herein without departing from the scope of the disclosure.

[0073] For example, turning back to FIG. 2, in some embodiments, a plurality of waveguides 240 can be provided. The plurality of waveguides 240 can be bonded to the light guide plate 130 to provide the back light unit 120 of the electronic display 100. In some embodiments, each waveguide 140 of the plurality of waveguides 240 can be identical; however, in some embodiments one or more waveguides of the plurality of waveguides 240 can include one or more features that are different from features of the other waveguides of the plurality of waveguides 240. In some embodiments, each waveguide 140 of the plurality of waveguides 240 can extend along the length 135 of the light guide plate 130. In some embodiments, each waveguide 140 of the plurality of waveguides 240 can be spaced a first distance 201 apart from each other (e.g., from an adjacent waveguide 140 of the plurality of waveguides 240) along the width 134 of the light guide plate 130. In some embodiments, a plurality of light sources 225 can be provided and each light source 125 of the plurality of light sources 225 can face a respective first edge 146 of a respective waveguide 140 of the plurality of waveguides 240. For example, each light source 125 of the plurality of light sources 225 can provide light from a respective light source 125 to the respective first edge 146 of the respective waveguide 140 of the plurality of waveguides 240.

[0074] Additionally, in some embodiments, each light source 125 of the plurality of light sources 225 can be spaced a second distance 202 apart from each other (e.g., from an adjacent light source 125 of the plurality of light sources 225) along the width 134 of the light guide plate 130. In some embodiments, the first distance 201 can be less than or equal to the second distance 202. In some embodiments, a first distance 201 between adjacent waveguides 140 of the plurality of waveguides 240 less than or equal to a second distance 202 between adjacent light sources 125 of the plurality of light sources 225 can provide an electronic display 100 that produces a higher quality electronic image as compared to, for example, an electronic image produced by an electronic display 100 where the first distance 201 is greater than the second distance 202. For example, if the first distance 201 is greater than the second distance 202, in some embodiments, light provided to the respective first edge 146 of the respective waveguide 140 of the plurality of waveguides 240 from the respective light source 125 of the plurality of light sources 225 may produce a black (e.g., non-illuminated or relatively less illuminated) line between adjacent waveguides 140 of the plurality of waveguides 240. Black lines between adjacent waveguides 140 of the plurality of waveguides 240 may be undesirable, in some embodiments, because the light guide plate 130 and the back light unit 120 may reproduce the black lines on the display panel 110 of the electronic display 100 when the back light unit 120 is employed to illuminate the display panel 110. For example, the electronic image may then include black lines which can distort, degrade, and detract from the quality of the electronic image on the display panel 110 of the electronic display 100. Accordingly, in some embodiments, providing a first distance 201 between adjacent waveguides 140 of the plurality of waveguides 240 less than or equal to a second distance 202 between adjacent light sources 125 of the plurality of light sources 225 can improve the illumination characteristics of the back light unit 120, and provide additional optical advantages to the back light unit 120 and the electronic display 100.

[0075] Moreover, black lines between adjacent waveguides 140 of the plurality of waveguides 240 can be further reduced and eliminated by bonding the plurality of waveguides 240 to the light guide plate 130. For example, in some embodiments, at least one of air and a material having a refractive index less than or equal to about 1.2 can be provided between adjacent waveguides 140 of the plurality of waveguides 240. Light from each light source 125 of the plurality of light sources 225 can therefore propagate through the respective waveguide 140 of the plurality of waveguides 240. Based at least on the at least one of air and a material having a refractive index less than or equal to about 1.2 provided between adjacent waveguides 140 of the plurality of waveguides 240, the light may remain within the respective waveguide 140 illuminating the respective waveguide 140 without light propagating between adjacent waveguides 140 (e.g., from one waveguide 140 to one or more adjacent waveguides of the plurality of waveguides 240). Preventing light from propagating between adjacent waveguides 140 can provide independent illumination of any one or more waveguides 140 of the plurality of waveguides 240. However, if one or more adjacent waveguides 140 of the plurality of waveguides 240 are illuminated simultaneously, for example, a corresponding black line may appear between the adjacent one or more waveguides 140. By bonding the plurality of waveguides 240 to the light guide plate 130, the light from each respective waveguide 140 can propagate from the respective waveguide 140 into the light guide plate 130 and can spread (e.g., bleed) outward relative to the width 134 of the light guide plate 130 from the waveguide 140 across the light guide plate 130 to illuminate the light guide plate 130 between adjacent waveguides 140 of the plurality of waveguides 240. Accordingly, the back light unit 120 including a plurality of waveguides 240 bonded to the light guide plate 130 can provide both independent illumination of any one or more waveguides 140 of the plurality of waveguides 240 as well as a uniform illumination of the display panel 110 without producing black lines between adjacent waveguides 140 that may otherwise occur in embodiments where, for example, only a light guide plate 130 is provided, or where a plurality of waveguides 240 are provided alone or in combination with a light guide plate 130 but are not bonded to the light guide plate 130.

[0076] FIGS. 4-9 illustrate some exemplary embodiments of exemplary back light units of the electronic display 100 (with the display panel 110 of the electronic display 100 removed for clarity) in accordance with embodiments of the disclosure. In particular, FIG. 4 and FIG. 5 illustrate features of an exemplary back light unit 420; FIG. 6 and FIG. 7 illustrate features of an exemplary back light unit 620; and FIG. 8 and FIG. 9 illustrate features of an exemplary back light unit 820. It is to be understood that the exemplary back light units 420, 620, 820 disclosed herein with reference to FIGS. 4-9 can include any one or more features of the electronic display 100 including any one or more features of the back light unit 120 including the light guide plate 130, the waveguide 140, the plurality of waveguides 240, the light source 125, the plurality of light sources 225, and the interface 150 between the light guide plate 130 and the waveguide 140 including, in some embodiments, the bonding agent 300 disclosed herein with reference to FIGS. 1-3. Likewise, it is to be understood that the back light unit 120 including the light guide plate 130, the waveguide 140, the plurality of waveguides 240, the light source 125, the plurality of light sources 225, and the interface 150 between the light guide plate 130 and the waveguide 140 including, in some embodiments, the bonding agent 300 disclosed herein with reference to FIGS. 1-3, can include any one or more features of the electronic display 100 including any one or more features of the exemplary back light units 420, 620, 820 disclosed herein with reference to FIGS. 4-9.

[0077] A side view of the back light unit 420 is shown in FIG. 4 and an alternate side view along line 5-5 of FIG. 4 of the back light unit 420 is shown in FIG. 5. In some embodiments, the back light unit 420 can include a light guide plate 430 and a plurality of waveguides 440 bonded to a major surface of the light guide plate 430. For example, a respective second major surface 442 of each waveguide of the plurality of waveguides 440 can be bonded to a first major surface 431 of the light guide plate 430 at a respective interface 400 between the light guide plate 430 and the respective waveguide of the plurality of waveguides 440. In some embodiments, a respective light source of a plurality of light sources 425 can face a respective edge 446 of a respective waveguide of the plurality of waveguides 440. Each light source of the plurality of light sources 425 can be oriented to provide light from the respective light source of the plurality of light sources 425 to the respective edge 446 of the respective waveguide of the plurality of waveguides 440.

[0078] In some embodiments, each light source of the plurality of light sources 425 can be independently illuminable. In some embodiments, providing each light source of the plurality of lights sources 425 as an independently illuminable light source can provide local one-dimensional dimming of a respective one or more waveguides of the plurality of waveguides 440. For example, by independently illuminating one or more waveguides of the plurality of waveguides 440, the back light unit 420 can include a local illuminated region corresponding to the profile of the illuminated one or more waveguides. Conversely, by not illuminating one or more waveguides of the plurality of waveguides 440, the back light unit 420 can include a local non-illuminated region corresponding to the profile of the non-illuminated one or more waveguides. Accordingly, by selectively illuminating (or not illuminating) selected waveguides of the plurality of waveguides 440, the back light unit 420 can provide local one-dimensional dimming of the display panel 110 of the electronic display 100. In some embodiments, local one-dimensional dimming can enhance contrast between, for example, light colors (e.g., white) and dark colors (e.g., black) that may be provided in an electronic image of the display panel 110 of the electronic display 100. Accordingly, the back light unit 420 can include local one-dimensional dimming capabilities that can enhance the optical and visual quality of the electronic display 100.

[0079] A side view of the back light unit 620 is shown in FIG. 6 and an alternate side view along line 7-7 of FIG. 6 of the back light unit 620 is shown in FIG. 7. In some embodiments, the back light unit 620 can include a light guide plate 630 with a first plurality of waveguides 640a bonded to a first major surface 631 of the light guide plate 630 and a second plurality of waveguides 640b bonded to an opposing second major surface 632 of the light guide plate 630. For example, a respective second major surface 642 of a respective waveguide of the first plurality of waveguides 640a can be bonded to the first major surface 631 of the light guide plate 630 at a respective first interface 600a. Likewise, a respective first major surface 641 of a respective waveguide of the second plurality of waveguides 640b can be bonded to the second major surface 632 of the light guide plate 630 at a respective second interface 600b. In some embodiments, each waveguide of the second plurality of waveguides 640b can be aligned with a respective waveguide of the first plurality of waveguides 640a to extend along the length of the light guide plate 630. In some embodiments, each waveguide of the first plurality of waveguides 640a can be parallel to each waveguide of the second plurality of waveguides 640b. In some embodiments, each waveguide of the second plurality of waveguides 640b can be spaced the first distance 201 (e.g., as described in FIG. 2) apart from each other (e.g., apart from an adjacent waveguide of the second plurality of waveguides 640b) along the width of the light guide plate 630.

[0080] In some embodiments, each light source of a plurality of light sources 625 can face at least one of a respective edge 646a of a respective waveguide of the first plurality of waveguides 640a and a respective edge 646b of a respective waveguide of the second plurality of waveguides 640b. Each light source of the plurality of light sources 625 can be oriented to provide light from the respective light source of the plurality of light sources 625 to at least one of a respective edge 646a of a respective waveguide of the first plurality of waveguides 640a and a respective edge 646b of a respective waveguide of the second plurality of waveguides 640b. For example, each light source of the plurality of light sources 625 can provide light from the respective light source of the plurality of light sources 625 to a respective edge 646a, 646b of a respective aligned pair of waveguides of the first plurality of waveguides 640a and the second plurality of waveguides 640b. In some embodiments, each light source of the plurality of light sources 625 can be independently illuminable. In some embodiments, providing each light source of the plurality of light sources 625 as an independently illuminable light source can provide local one-dimensional dimming of an aligned pair of a respective one or more waveguides of the first plurality of waveguides 640a and the second plurality of waveguides 640b. Moreover, by aligning each waveguide of the first plurality of waveguides 640a with each waveguide of the second plurality of waveguides 640b, a thickness of the light guide plate 630 can be reduced while still providing the advantages obtained from the light guide plate as disclosed herein. For example, efficient coupling between a respective light emitting region of each light source of the plurality of light sources 625 and a respective edge 646a of a respective waveguide of the first plurality of waveguides 640a and a respective edge 646b of a respective waveguide of the second plurality of waveguides 640b can be achieved. In addition to providing a thinner light guide plate 630, each waveguide of the first plurality of waveguides 640a and each waveguide of the second plurality of waveguides 640b can individually be thinner as compared to the comparable thickness of a single waveguide. Accordingly, the features of the back light unit 620 can provide manufacturing, structural, and optical advantages.

[0081] A side view of a back light unit 820 is shown in FIG. 8 and an alternate side view along line 9-9 of FIG. 8 of the back light unit 820 is shown in FIG. 9. In some embodiments, the back light unit 820 can include a first light guide plate 830 and a second light guide plate 860. In some embodiments, a first plurality of waveguides 840 can be bonded to the first light guide plate 830 and a second plurality of waveguides 880 can be bonded to the second light guide plate 860. For example, a respective second major surface 842 of each waveguide of the first plurality of waveguides 840 can be bonded to a first major surface 831 of the first light guide plate 830 at a respective first interface 801 between the first light guide plate 830 and the respective waveguide of first plurality of waveguides 840. Likewise, a respective second major surface 882 of each waveguide of the second plurality of waveguides 880 can be bonded to a first major surface 861 of the second light guide plate 860 at a respective second interface 802 between the second light guide plate 860 and the respective waveguide of the second plurality of waveguides 880.

[0082] In some embodiments, each light source of a first plurality of light sources 825 can face a respective edge 846 of a respective waveguide of the first plurality of waveguides 840. Each light source of the first plurality of light sources 825 can be oriented to provide light from a respective light source of the first plurality of light sources 825 to a respective edge 846 of a respective waveguide of the first plurality of waveguides 840. Likewise, in some embodiments, each light source of a second plurality of light sources 850 can face a respective edge 886 of a respective waveguide of the second plurality of waveguides 880. Each light source of the second plurality of light sources 850 can be oriented to provide light from a respective light source of the second plurality of light sources 850 to a respective edge 886 of the respective waveguide of the second plurality of waveguides 880. In some embodiments, the second light guide plate 860 can be oriented with the first major surface 861 facing a second major surface 832 of the first light guide plate 830. In some embodiments, the first light guide plate 830 can be spaced apart from the second light guide plate 860 thereby defining a gap 875 between the second major surface 832 of the first light guide plate 830 and a respective first major surface 881 of each waveguide of the second plurality of waveguides 880. In some embodiments, the gap 875 can include at least one of air and a material having a refractive index less than or equal to about 1.2.

[0083] Light from each light source of the first plurality of light sources 825 can illuminate the first light guide plate 830 and each waveguide of the first plurality of waveguides 840. Likewise, light from each light source of the second plurality of light sources 850 can illuminate the second light guide plate 860 and each waveguide of the second plurality of waveguides 880. The first light guide plate 830 and the first plurality of waveguides 840 as well as the second light guide plate 860 and the second plurality of waveguides 880 can therefore illuminate the display panel 110 of the electronic display 100. Based at least on the at least one of air and a material having a refractive index less than or equal to about 1.2 provided in the gap 875 between the second major surface 832 of the first light guide plate 830 and the respective first major surface 881 of each waveguide of the second plurality of waveguides 880, the light may remain within the respective waveguide of first plurality of waveguides 840 illuminating the respective waveguide of first plurality of waveguides 840 without propagating to the second light guide plate 860 and the waveguides of the second plurality of waveguides 880. Similarly, based at least on the at least one of air and a material having a refractive index less than or equal to about 1.2 provided in the gap 875, the light may remain within the respective waveguide of the second plurality of waveguides 880 illuminating the respective waveguide of the second plurality of waveguides 880 without propagating to the first light guide plate 830 and the waveguides of the first plurality of waveguides 840.

[0084] Preventing light from propagating between the waveguides of the first plurality of waveguides 840 and the waveguides of the second plurality of waveguides 880 can provide independent illumination of any one or more waveguides of the first plurality of waveguides 840 and any one or more waveguides of the second plurality of waveguides 880. For example, in some embodiments, each light source of the first plurality of light sources 825 and each light source of the second plurality of light sources 850 can be independently illuminable. In some embodiments, providing each light source of the first plurality of light sources 825 and each light source of the second plurality of light sources 850 as independently illuminable light sources can provide at least one of local one-dimensional dimming and local two-dimensional dimming of one or more waveguides of the first plurality of waveguides 840 and one or more waveguides of the second plurality of waveguides 880. In some embodiments, each light source of the first plurality of light sources 825 can be independently illuminable. In some embodiments, providing each light source of the first plurality of light sources 825 as an independently illuminable light source can provide local one-dimensional dimming of a respective one or more waveguides of the first plurality of waveguides 840. For example, by independently illuminating one or more waveguides of the first plurality of waveguides 840, the back light unit 820 can include a local illuminated region corresponding to the profile of the illuminated one or more waveguides of the first plurality of waveguides 840. Conversely, by not illuminating one or more waveguides of the first plurality of waveguides 840, the back light unit 820 can include a local non- illuminated region corresponding to the profile of the non-illuminated one or more waveguides of the first plurality of waveguides 840. Similarly, in some embodiments, each light source of the second plurality of light sources 850 can be independently illuminable. In some embodiments, providing each light source of the second plurality of light sources 850 as an independently illuminable light source can provide local one- dimensional dimming of a respective one or more waveguides of the second plurality of waveguides 880. For example, by independently illuminating one or more waveguides of the second plurality of waveguides 880, the back light unit 820 can include a local illuminated region corresponding to the profile of the illuminated one or more waveguides of the second plurality of waveguides 880. Conversely, by not illuminating one or more waveguides of the second plurality of waveguides 880, the back light unit 820 can include a local non-illuminated region corresponding to the profile of the non- illuminated one or more waveguides of the second plurality of waveguides 880.

[0085] In some embodiments, each light source of the first plurality of light sources 825 and each light source of the second plurality of light sources 850 can be independently illuminable. In some embodiments, providing each light source of the first plurality of light sources 825 and each light source of the second plurality of light sources 850 as an independently illuminable light source can provide local one-dimensional dimming of a respective one or more waveguides of the first plurality of waveguides 840 in a first direction and a respective one or more waveguides of the second plurality of waveguides 880 in a second direction. For example, by independently illuminating one or more waveguides of the first plurality of waveguides 840 and one or more waveguides of the second plurality of waveguides 880, the back light unit 820 can include a local illuminated region corresponding to the profile of the illuminated one or more waveguides of the first plurality of waveguides 840 in the first direction and the profile of the illuminated one or more waveguides of the second plurality of waveguides 880 in the second direction. Conversely, by not illuminating one or more waveguides of the first plurality of waveguides 840 and one or more waveguides of the second plurality of waveguides 880, the back light unit 820 can include a local non-illuminated region corresponding to the profile of the non-illuminated one or more waveguides of the first plurality of waveguides 840 in the first direction and the profile of the non-illuminated one or more waveguides of the second plurality of waveguides 880 in the second direction. In some embodiments, each waveguide of the first plurality of waveguides 840 can be perpendicular to each waveguide of the second plurality of waveguides 880, and each waveguide of the first plurality of waveguides 840 can extend along the first direction perpendicular to the second direction along which each waveguide of the second plurality of waveguides 880 can extend. Moreover, each waveguide of the first plurality of waveguides 840 can optically intersect each waveguide of the second plurality of waveguides 880 at a location where the first direction intersects (e.g., overlays) the second direction.

[0086] Accordingly, by selectively illuminating (or not illuminating) selected waveguides of the first plurality of waveguides 840 and selected waveguides of the second plurality of waveguides 880, the back light unit 820 can provide local one- dimensional dimming of the display panel 110 of the electronic display 100 in a first direction and a second direction as well as local two-dimensional dimming of the display panel 110 of the electronic display 100 in the first direction and the second direction. In some embodiments, local one-dimensional dimming and local two-dimensional dimming can enhance contrast between, for example, light colors (e.g., white) and dark colors (e.g., black) that may be provided in an electronic image of the display panel 110 of the electronic display 100. Accordingly, the back light unit 820 can include local one- dimensional dimming and local two-dimensional dimming capabilities that can enhance the optical and visual quality of the electronic display 100.

[0087] It will be appreciated that the various disclosed embodiments may involve particular features, elements or steps that are described in connection with that particular embodiment. It will also be appreciated that a particular feature, element or step, although described in relation to one particular embodiment, may be interchanged or combined with alternate embodiments in various non-illustrated combinations or permutations.

[0088] It is to be understood that, as used herein the terms "the," "a," or "an," mean "at least one," and should not be limited to "only one" unless explicitly indicated to the contrary. Thus, for example, reference to "a component" includes embodiments having two or more such components unless the context clearly indicates otherwise.

[0089] Ranges can be expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, embodiments include from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0090] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that any particular order be inferred.

[0091] While various features, elements or steps of particular embodiments may be disclosed using the transitional phrase "comprising," it is to be understood that alternative embodiments, including those that may be described using the transitional phrases "consisting" or "consisting essentially of," are implied. Thus, for example, implied alternative embodiments to an apparatus that comprises A+B+C include embodiments where an apparatus consists of A+B+C and embodiments where an apparatus consists essentially of A+B+C.

[0092] It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the spirit and scope of the disclosure. Thus, it is intended that the present disclosure cover the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.

Claims

CLAIMS What is claimed is:

1. A back light unit comprising:

a light guide plate;

a waveguide bonded to a major surface of the light guide plate; and

a light source facing an edge of the waveguide, wherein the light source is oriented to provide light from the light source to the edge of the waveguide.

2. An electronic display comprising the back light unit of claim 1, wherein the back light unit is oriented to face a major surface of a display panel.

3. The back light unit of claim 1, wherein the light source comprises an LED.

4. The back light unit of claim 1, wherein the light guide plate and the waveguide both comprise the same material.

5. The back light unit of claim 1, wherein the light guide plate and the waveguide both comprise glass.

6. The back light unit of claim 1, wherein the light guide plate and the waveguide comprise different materials.

7. The back light unit of claim 1, wherein the light guide plate comprises glass and the waveguide comprises a polymer material.

8. The back light unit of claim 1, wherein Van der Waals forces between the waveguide and the light guide plate bond the waveguide to the light guide plate.

9. The back light unit of claim 1, wherein the waveguide is bonded to the light guide plate with a bonding agent.

10. The back light unit of claim 9, wherein the bonding agent is transparent to visible light.

11. The back light unit of claim 1, wherein the waveguide comprises a material that directly bonds to the light guide plate without a separate bonding agent.

12. The back light unit of claim 11, wherein the light guide plate comprises glass and the waveguide comprises a polymer material.

13. The back light unit of claim 1, wherein a thickness of the light guide plate is defined between the major surface of the light guide plate and an opposing major surface of the light guide plate, and a height of a light emitting region of the light source parallel to the thickness of the light guide plate is greater than the thickness of the light guide plate.

14. The back light unit of claim 13, wherein a thickness of the waveguide parallel to the thickness of the light guide plate is defined between opposing major surfaces of the waveguide, and the thickness of the waveguide is greater than or equal to a difference between the height of the light emitting region of the light source and the thickness of the light guide plate.

15. The back light unit of claim 13, wherein a width of the waveguide is defined along the edge of the waveguide perpendicular to the thickness of the light guide plate, and a width of the light emitting region of the light source parallel to the width of the waveguide is less than or equal to the width of the waveguide.

16. The back light unit of claim 1, wherein the waveguide is a slab waveguide.

17. The back light unit of claim 16, wherein the slab waveguide has a rectangular cross- sectional profile.

18. A back light unit comprising:

a light guide plate;

a first plurality of waveguides bonded to a first major surface of the light guide plate; and

a plurality of light sources, wherein each light source of the plurality of light sources faces a respective edge of a respective waveguide of the first plurality of waveguides, and wherein each light source of the plurality of light sources is oriented to provide light from a respective light source of the plurality of light sources to the respective edge of the respective waveguide of the first plurality of waveguides.

19. An electronic display comprising the back light unit of claim 18, wherein the back light unit is oriented to face a major surface of a display panel.

20. The back light unit of claim 18, wherein a thickness of the light guide plate is defined between the first major surface of the light guide plate and a second major surface of the light guide plate, wherein a width of the light guide plate is defined along a first edge of the light guide plate perpendicular to the thickness of the light guide plate, wherein a length of the light guide plate is defined along a second edge of the light guide plate perpendicular to the first edge of the light guide plate, wherein each waveguide of the first plurality of waveguides extends along the length of the light guide plate, and wherein each waveguide of the first plurality of waveguides is spaced a first distance apart from an adjacent waveguide of the first plurality of waveguides along the width of the light guide plate.

21. The back light unit of claim 20, wherein each light source of the plurality of light sources is spaced a second distance apart from an adjacent light source of the plurality of light sources along the width of the light guide plate, and wherein the first distance is less than or equal to the second distance.

22. The back light unit of claim 20, wherein at least one of air and a material having a refractive index less than or equal to about 1.2 is provided between adjacent waveguides of the first plurality of waveguides.

23. The back light unit of claim 20, wherein each light source of the plurality of light sources is independently illuminable.

24. The back light unit of claim 20, further comprising a second plurality of waveguides bonded to the second major surface of the light guide plate, wherein each waveguide of the second plurality of waveguides is aligned with a respective waveguide of the first plurality of waveguides, wherein each waveguide of the second plurality of waveguides extends along the length of the light guide plate parallel to the respective waveguide of the first plurality of waveguides, and wherein each waveguide of the second plurality of waveguides is spaced the first distance apart from an adjacent waveguide of the second plurality of waveguides along the width of the light guide plate.

25. An electronic display comprising the back light unit of claim 24, wherein the back light unit is oriented to face a major surface of a display panel.

26. The back light unit of claim 24, wherein each light source of the plurality of light sources faces a respective edge of a respective waveguide of the second plurality of waveguides, and wherein each light source of the plurality of light sources is further oriented to provide light from a respective light source of the plurality of light sources to the respective edge of the respective waveguide of the second plurality of waveguides.

27. The back light unit of claim 24, wherein each light source of the plurality of light sources is independently illuminable.

28. A back light unit comprising:

a first light guide plate;

a first plurality of waveguides bonded to a first major surface of the first light guide plate;

a first plurality of light sources, wherein each light source of the first plurality of light sources faces a respective edge of a respective waveguide of the first plurality of waveguides, and wherein each light source of the first plurality of light sources is oriented to provide light from a respective light source of the first plurality of light sources to the respective edge of the respective waveguide of the first plurality of waveguides;

a second light guide plate oriented with a first major surface facing a second major surface of the first light guide plate;

a second plurality of waveguides bonded to the first major surface of the second light guide plate; and

a second plurality of light sources, wherein each light source of the second plurality of light sources faces a respective edge of a respective waveguide of the second plurality of waveguides, wherein each light source of the second plurality of light sources is oriented to provide light from a respective light source of the second plurality of light sources to the respective edge of the respective waveguide of the second plurality of waveguides.

29. An electronic display comprising the back light unit of claim 28, wherein the back light unit is oriented to face a major surface of a display panel.

30. The back light unit of claim 28, wherein each waveguide of the first plurality of waveguides is perpendicular to each waveguide of the second plurality of waveguides.

31. The back light unit of claim 28, wherein a thickness of the first light guide plate is defined between the first major surface of the first light guide plate and the second major surface of the first light guide plate, wherein a width of the first light guide plate is defined along a first edge of the first light guide plate perpendicular to the thickness of the first light guide plate, wherein a length of the first light guide plate is defined along a second edge of the first light guide plate perpendicular to the first edge of the first light guide plate, wherein each waveguide of the first plurality of waveguides extends along the length of the first light guide plate, wherein each waveguide of the first plurality of waveguides is spaced a first distance apart from an adjacent waveguide of the first plurality of waveguides along the width of the first light guide plate; wherein a thickness of the second light guide plate parallel to the thickness of the first light guide plate is defined between the first major surface of the second light guide plate and a second major surface of the second light guide plate, wherein a width of the second light guide plate parallel to the width of the first light guide plate is defined along a first edge of the second light guide plate perpendicular to the thickness of the second light guide plate, wherein a length of the second light guide plate is defined along a second edge of the second light guide plate perpendicular to the first edge of the second light guide plate, wherein each waveguide of the second plurality of waveguides extends along the width of the second light guide plate, and wherein each waveguide of the second plurality of waveguides is spaced a second distance apart from an adjacent waveguide of the second plurality of waveguides along the length of the second light guide plate.

32. The back light unit of claim 31, wherein each waveguide of the first plurality of waveguides is perpendicular to each waveguide of the second plurality of waveguides.

33. The back light unit of claim 28, wherein the first light guide plate is spaced apart from the second light guide plate, thereby defining a gap between the second major surface of the first light guide plate and the second plurality of waveguides.

34. The back light unit of claim 33, wherein the gap comprises at least one of air and a material having a refractive index less than or equal to about 1.2.

35. The back light unit of claim 28, wherein each light source of the first plurality of light sources and each light source of the second plurality of light sources is independently illuminable.