阅读说明：本技术 包括具有沟槽的光导板的光装置和用于使用所述光装置来引导光的方法 (Light device including light guide plate having grooves and method for guiding light using the same ) 是由 李申平 于 2019-07-30 设计创作，主要内容包括：一种光装置可以包括光源和光导板,所述光导板可以更包括主要面,所述主要面包括多条沟槽。所述多条沟槽中的每条沟槽均可以包括第一表面和相对的第二表面。每条沟槽均可以具有最大深度,所述最大深度可以界定在第二主要面与对应沟槽的基部之间。在一些实施方式中,每条沟槽的一或更多个表面均可以包括第一凸面部分。在其他的实施方式中,所述多条沟槽中的每条沟槽的最大深度可以从约1微米到约50微米。在又其他的实施方式中,可以使用所述光装置来将光引导出光导板,其中峰值辐射率相对于与所述光导板的第一主要面正交的方向从0°到30°而定向。(A light apparatus may include a light source and a light guide plate, the light guide plate may further include a major surface, the major surface including a plurality of grooves. Each groove of the plurality of grooves may include a first surface and an opposing second surface. Each groove may have a maximum depth, which may be defined between the second major face and the base of the respective groove. In some embodiments, one or more surfaces of each groove may include a first convex portion. In other embodiments, each trench of the plurality of trenches may have a maximum depth of from about 1 micron to about 50 microns. In yet other embodiments, the light device may be used to direct light out of a light guide plate with a peak radiance oriented from 0 ° to 30 ° relative to a direction normal to the first major face of the light guide plate.)

1. A light device, comprising:

a light guide plate comprising a first major surface, a second major surface, and a first edge extending between the first major surface and the second major surface, the second major surface comprising a plurality of grooves, each groove of the plurality of grooves comprising a first surface and a second surface opposite the first surface, the first surface of each groove comprising a first convex portion and defining a maximum depth of each groove between the second major surface and a base of the corresponding groove; and

a light source positioned to emit light into the first edge of the light guide plate.

2. The light device of claim 1, wherein the maximum depth of each trench is from about 1 micron to about 50 microns.

3. The light device of any one of claims 1-2, wherein a depth angle of the first convex portion of the first surface of each trench is from about 10 ° to about 55 °.

4. The light device of any one of claims 1-3, wherein the first convex portion of the first surface of each groove comprises a radius of curvature.

5. The light device of claim 4, wherein the radius of curvature of the first convex portion of the first surface of each groove is equal to the maximum depth of the corresponding groove.

6. The light device of any one of claims 1 to 5, wherein the first convex portion of the first surface of each groove is closer to the light source than the second surface of the corresponding groove.

7. The light device of any one of claims 1 to 6, wherein the second surface of each trench comprises a second convex portion.

8. The light device of claim 7, wherein the depth angle of the second convex portion of the second surface of each trench is from about 1 ° to about 55 °.

9. The light apparatus of any one of claims 3 and 8, wherein the depth angle of the first convex portion of the first surface of each groove of the plurality of grooves varies as a function of the distance of the groove from the first edge.

10. The light device of any one of claims 7 to 9, wherein the depth angle of the first convex portion of the first surface and the depth angle of the second convex portion of the second surface are the same for each trench.

11. The light device of claims 7-10, wherein the first convex portion of the first surface and the second convex portion of the second surface of each trench meet at the base.

12. The light device of any one of claims 1-11, wherein a pair of surfaces of each of the plurality of grooves meet at the base.

13. The light device of any one of claims 1 to 12, wherein the base comprises a pointed corner.

14. An optical device, comprising:

a light guide plate comprising a first major surface, a second major surface, and a first edge extending between the first major surface and the second major surface, the second major surface comprising a plurality of grooves, each groove of the plurality of grooves comprising a maximum depth from about 1 micron to about 50 microns; and

a light source positioned to emit light into the first edge of the light guide plate.

15. The light device of any one of claims 1 to 14, wherein a reflector body faces the second major face of the light guide plate.

16. The light device of any one of claims 1-15, wherein the grooves of the plurality of grooves are spaced apart from each other and extend substantially parallel to the first edge.

17. The light device of any one of claims 1-16, wherein the first edge is substantially straight.

18. The light device of claim 17, wherein the maximum depth of each trench of the plurality of trenches increases as the distance of the trench from the first edge increases.

19. The light device of any one of claims 1-16, wherein the maximum depth of each trench is between about 1 micron and about 30 microns.

20. The light device of any one of claims 1-19, wherein the first major surface and the second major surface of the light guide plate each comprise a quadrilateral shape, the light guide plate further comprising a second edge extending between the first major surface and the second major surface, opposite the first edge; a third edge extending from the first edge to the second edge and a fourth edge opposite the third edge, a length of the light-guide plate defined between the first edge and the second edge, a width of the light-guide plate defined between the third edge and the fourth edge.

21. The light apparatus of claim 20, wherein a spacing between adjacent pairs of the plurality of grooves along the length of the light guide plate decreases as a distance of the adjacent pairs of grooves from the first edge increases.

22. The light device of any one of claims 20 to 21, wherein the spacing between the adjacent pairs of grooves along the length of the light guide plate is from about 10 microns to about 5 millimeters.

23. The light device of any one of claims 20-22, wherein each groove of the plurality of grooves extends continuously for a length along a corresponding groove path from the third edge to the fourth edge.

24. The light apparatus of claim 23, wherein the length of each groove of the plurality of grooves is equal to the width of the light guide plate.

25. The light device of claim 23, wherein each trench of the plurality of trenches is separated from another trench of the plurality of trenches in the same trench path by about 50 microns to about 100 millimeters.

26. The light device as claimed in any one of claims 23 and 25, wherein the grooves in a first grooved path are interleaved with the grooves in a second grooved path adjacent to the first grooved path in the direction of the width of the light guide plate.

27. A method of emitting light with the light device of any one of claims 1-26, the method comprising:

injecting light emitted from the light source through the first edge of the light guide plate and into the light guide plate;

propagating the light injected into the light guide plate by total internal reflection, at least a portion of the propagated light exiting the light guide plate into at least one groove of the plurality of grooves; and

wherein at least 20% of the propagating light exiting the light guide plate into the at least one groove is directed back into the light guide plate.

28. The method of claim 27, further comprising: passing the light propagating in the light guide plate through the first major face of the light guide plate with a peak radiance oriented from 0 ° to 30 ° relative to a direction orthogonal to the first major face of the light guide plate.

29. The method according to any one of claims 27 and 28, wherein at least 50% of the propagating light exiting the light guide plate into the at least one groove is directed back into the light guide plate.

30. A method of emitting light with the light device of any one of claims 1 to 26, the method comprising:

injecting light emitted from the light source through the first edge of the light guide plate and into the light guide plate;

propagating the injected light within the light guide plate by total internal reflection;

passing the light propagating in the light guide plate through the first major face of the light guide plate, wherein a peak radiance is oriented from about 0 ° to about 30 ° relative to a direction orthogonal to the first major face of the light guide plate.

31. The method according to any one of claims 28 and 30, wherein the peak radiance is oriented from about 0 ° to about 10 ° relative to a direction orthogonal to the first major face of the light guide plate.

Technical Field

The present disclosure relates generally to light devices comprising light guide plates with grooves and methods for guiding light using the light devices, and more particularly to light devices comprising light guide plates comprising grooves, wherein each groove further comprises two surfaces and a base, and methods for guiding light using the light devices.

Background

It is known to use light devices in display devices, including Liquid Crystal Displays (LCDs) and the like, to illuminate the display. For compactness, such light devices typically employ a light source that is emitted into the edge of the light guide plate to propagate light through the light guide plate.

Disclosure of Invention

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

According to some embodiments, a light device may include a light guide plate and a light source. The light guide plate may further include a first major surface, a second major surface, and a first edge extending between the first major surface and the second major surface. The second major surface of the light guide plate may further include a plurality of grooves, wherein each of the plurality of grooves may include a first surface and a second surface opposite to the first surface. The first surface of each groove may further include a first convex portion. A maximum depth of each groove may be defined between a base of the corresponding groove and the second major surface of the light guide plate. Further, the light source may be positioned to emit light into the first edge of the light guide plate.

In some embodiments, the maximum depth of each groove in the light guide plate of the light device may be from about 1 micron to about 50 microns.

In further embodiments, the depth angle of the first convex portion of the first surface of each groove in the light guide plate of the light device may be from about 10 ° to about 55 °.

In further embodiments, the first convex portion of the first surface of each groove in the light guide plate of the light device may include a radius of curvature.

In still further embodiments, the radius of curvature of the first convex portion of the first surface of each groove in the light guide plate of the light device may be equal to the maximum depth of the corresponding groove.

In other embodiments, the first convex portion of the first surface of each groove in the light guide plate of the light device may be closer to the light source than the second surface of the corresponding groove.

In other embodiments, the second surface of each groove in the light guide plate of the light device may include a second convex portion.

In further embodiments, the depth angle of the second convex portion of the second surface of each groove in the light guide plate of the light device may be from about 1 ° to about 55 °.

In some further embodiments, the depth angle of the first convex portion of the first surface of each groove of the plurality of grooves may vary as a function of the distance of the groove from the first edge.

In yet other further embodiments, the depth angle of the first convex portion of the first surface and the depth angle of the second convex portion of the second surface may be the same for each groove in the light guide plate of the light device.

In yet other further embodiments, the first convex portion of the first surface and the second convex portion of the second surface of each groove may meet at the base of a corresponding groove in the light guide plate of the light device.

In other embodiments, a surface pair of each of the plurality of grooves may meet at the base of a corresponding groove in the light guide plate of the light device.

In yet other embodiments, the base of each groove in the light guide plate of the light device may include a sharp corner.

In other embodiments, a light apparatus may include a light guide plate and a light source. The light guide plate may further include a first major surface, a second major surface, and a first edge extending between the first major surface and the second major surface. The second major surface may further include a plurality of grooves. Each trench of the plurality of trenches may further comprise a maximum depth of from about 1 micron to about 50 microns. The light source may be positioned to emit light into the first edge of the light guide plate.

In further embodiments, the light device may further comprise a reflector, which may face the second main surface of the light guide plate.

In other embodiments, the grooves of the plurality of grooves in the light guide plate of the light device may be spaced apart from each other and extend substantially parallel to the first edge.

In yet other embodiments, the first edge of the light guide plate in the light device may be substantially straight.

In other embodiments, the first major surface and the second major surface of the light guide plate may each include a quadrilateral shape. The light guide plate may further include a second edge extending between the first main surface and the second main surface. The light guide plate may have a third edge extending from the first edge toward the second edge and a fourth edge opposite to the third edge, opposite to the first edge. A length of the light guide plate may be defined between the first edge and the second edge. A width of the light guide plate may be defined between the third edge and the fourth edge.

In further embodiments, a spacing between adjacent pairs of the plurality of grooves along the length of the light guide plate of the light device decreases as a distance of the adjacent pairs of grooves from the first edge increases.

In other further embodiments, the spacing between the adjacent groove pairs along the length of the light guide plate is from about 10 microns to about 5 millimeters.

In further embodiments, each groove of the plurality of grooves extends continuously for a length along a corresponding groove path from the third edge to the fourth edge of the light guide plate of the light device.

In further embodiments, the length of each groove of the plurality of grooves is equal to the width of the light guide plate of the light device.

In other further embodiments, each of the plurality of grooves is separated from another of the plurality of grooves in the same groove path in the light guide plate of the light device by about 50 microns to about 100 millimeters.

In yet other further embodiments, the grooves in a first groove path are interleaved with the grooves in a second groove path adjacent to the first groove path of the light guide plate of the light device in the direction of the width of the light guide plate.

In yet other further embodiments, the maximum depth of each trench of the plurality of trenches may be between about 1 micron and about 30 microns.

In other embodiments, the maximum depth of each of the plurality of grooves may increase as the distance of the groove from the first edge increases.

According to some embodiments, the method of emitting light may involve using one of the light devices discussed above. The method may involve injecting light emitted from the light source through the first edge of the light guide plate and into the light guide plate. Also, the method may involve propagating light into the light guide plate by total internal reflection. At least a portion of the light in the light guide plate may exit the light guide plate into at least one of the plurality of grooves in the light guide plate. Such an approach may direct at least 20% of the light exiting the light guide plate into at least one groove back into the light guide plate.

In further embodiments, the method may further comprise the steps of: passing the light in the light guide plate through the first major face of the light guide plate, wherein a peak radiance is oriented from about 0 ° to about 30 ° relative to a direction orthogonal to the first major face of the light guide plate.

In other further embodiments, the method may direct at least 50% of the propagating light exiting the light guide plate into the at least one groove back into the light guide plate.

According to other embodiments, the method of emitting light may involve the use of one of the light devices discussed above. The method may involve injecting light emitted from the light source through the first edge of the light guide plate and into the light guide plate. Also, the method may involve propagating light within the light guide plate by total internal reflection. Further, the method may involve passing the light in the light guide plate through the first major face of the light guide plate with a peak radiance oriented from about 0 ° to about 30 ° relative to a direction orthogonal to the first major face of the light guide plate.

In further embodiments, the peak radiance may be oriented from about 0 ° to about 10 ° relative to a direction orthogonal to the first major face of the light guide plate.

Drawings

These and other features, aspects, and advantages will become better understood when the following detailed description is read with reference to the accompanying drawings, wherein:

FIG. 1 depicts a cross-sectional side view of an exemplary embodiment of a light device including a light guide plate having a second major surface including a plurality of grooves;

FIG. 2 is an enlarged view 2 of FIG. 1, showing a surface profile of one of the plurality of grooves in accordance with the first exemplary embodiment of the light device;

FIG. 3 is an alternative enlarged view 2 of FIG. 1, showing a surface profile of one of the plurality of grooves in accordance with a second exemplary embodiment of a light device;

FIG. 4 is an alternative enlarged view 2 of FIG. 1, depicting a surface profile of one of the plurality of grooves in accordance with a third exemplary embodiment of a light device;

FIG. 5 is an alternative enlarged view 2 of FIG. 1, depicting a surface profile of one of the plurality of grooves in accordance with a fourth exemplary embodiment of a light device;

FIG. 6 is an alternative enlarged view 2 of FIG. 1, depicting a surface profile of one of the plurality of grooves in accordance with a fifth exemplary embodiment of a light device;

FIG. 7 is an alternative enlarged view 2 of FIG. 1, showing a surface profile of one of the plurality of grooves in accordance with a sixth exemplary embodiment of a light device;

FIG. 8 depicts a cross-section taken along line 8-8 in FIG. 1, showing a first exemplary embodiment of an arrangement of the plurality of grooves of the second major face of the light guide plate;

FIG. 9 depicts another cross-section taken along line 8-8 in FIG. 1, showing a second exemplary embodiment of the arrangement of the plurality of grooves of the second major face of the light guide plate;

FIG. 10 depicts the angular distribution of light exiting the first major face of the light guide plate when the second major face has slanted grooves with a maximum depth of 5 microns for different depth angles;

FIG. 11 depicts the angular distribution of light exiting the first major surface of the light guide plate when the second major surface has concave grooves with a maximum depth of 5 microns for different depth angles;

FIG. 12 depicts the angular distribution of light exiting the first major surface of the light guide plate when the second major surface has convex grooves with a maximum depth of 5 microns for different depth angles;

fig. 13 depicts the angular distribution of light exiting the first major face of the light guide plate when the second major face has either of a slanted groove or a concave groove, the grooves having a depth angle of 35 ° for different maximum depths;

FIG. 14 depicts the percentage of light exiting the light guide plate into the convex grooves and directed back into the light guide plate as a function of the depth angle of the convex grooves; and

fig. 15 shows the percentage of light that exits the light guide plate into the convex grooves and is directed back into the light guide plate as a function of the width of the grooves.

Detailed Description

Embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

For example, fig. 1 schematically depicts a cross-sectional side view of an exemplary embodiment of a light device 101. The light device 101 may comprise a light guide plate 105 comprising a first main face 109 and a second main face 111 opposite the first main face 109. As shown, the first major face 109 may extend along a first planar face, and the second major face 111 may extend along a second planar face. Although not shown, in some embodiments, the first major face 109 and the second major face 111 may extend along a curved face. Also, as shown, the first major face 109 may extend parallel to the second major face 111, wherein the thickness 108 may be defined between the first and second major faces 109, 111 between adjacent pairs of trenches (defined below). In such examples, the thickness 108 may be in a range of 100 microns to about 10 millimeters, although other thicknesses may also be provided in further embodiments. In some embodiments, the thickness 108 may be between about 200 microns and about 6 microns, between about 200 microns and about 3 millimeters, between about 200 microns and about 800 microns, or between about 200 microns and about 500 microns. In other embodiments, the thickness 108 may be about 10 millimeters or less, about 6 millimeters or less, about 3 millimeters or less, about 2 millimeters or less, about 1 millimeter or less, about 500 micrometers or less, or about 200 micrometers or less. In embodiments where a small thickness is desired, the thickness 108 may preferably be about 1 millimeter or less, about 500 microns or less, or even about 200 microns or less. In yet other embodiments, the thickness 108 may be about 100 microns or greater, about 200 microns or greater, about 500 microns or greater, about 1 millimeter or greater, about 2 millimeters or greater, about 3 millimeters or greater, or about 6 millimeters or greater. Also, as shown, due to the substantially parallel arrangement of the first major surface 109 and the second major surface 111, a significant amount of the thickness 108 along the light guide plate 105 may be substantially constant. Although not shown, the first and second major faces 109, 111 between each adjacent pair of grooves may also extend at an acute angle relative to each other, rather than parallel to each other, wherein the thickness 108 may vary along the length and/or width of the light guide plate 105. In further embodiments, an acute angle between one adjacent pair of grooves on the second major face 111 may be different from another acute angle between a second adjacent pair of grooves on the second major face 111. In other embodiments, the first major face 109 may comprise a groove comprising a surface having a combination of convex, concave, and sloped portions (including those illustrated and described below for the second major face 111).

The major face of the light guide plate may include a wide range of shapes, such as a polygon having three or more sides (e.g., triangle, quadrangle), a curve (e.g., circle, ellipse), or a shape having a combination of polygonal and curved features. As shown in fig. 1 and 8-9, the first major surface 109 and the second major surface 111 of the light guide plate 105 may each comprise a rectangular shape. In such embodiments, the first edge 107 and the second edge 110 of the light guide plate 105 may each extend between the first major surface 109 and the second major surface 111. The first edge 107 and the second edge 110 may comprise straight edges that are parallel with respect to each other. Also, the second edge 110 may be positioned opposite the first edge 107 to define a length 112 of the light guide plate 105. As shown in fig. 8-9, the light guide plate 105 may further include a third edge 807 and a fourth edge 809, which may each extend between the first major surface 109 and the second major surface 111. The third and fourth edges 807 and 809 may comprise straight edges that are parallel with respect to each other. Also, a fourth edge 809 may be positioned opposite the third edge 807 to define a width 813 of the light guide plate 105. As such, the edges 107, 110, 807, 809 may likewise form a rectangular shape, with each of the third and fourth edges 807, 809 extending from the first edge 107 to the second edge 110 while being perpendicular to the first and second edges 107, 110. In some embodiments, the length 112 of the light guide plate 105 may be about the same as, greater than, or less than the width 813 of the light guide plate 105. In some embodiments, the length 112 and width 813 of light guide plate 105 may be equal to corresponding measurements of the associated display 115, although other lengths may also be provided in further embodiments. The length 112 of the light-guide plate 105 may be between about 100 microns to about 3 meters, between about 1 millimeter and about 2.05 meters, between about 10 millimeters and about 1.22 meters, or between about 25 millimeters and about 300 millimeters. In some embodiments, the width 813 of the light guide plate 105 may be between about 100 microns to about 3 meters, between about 1 millimeter and about 2.05 meters, between about 10 millimeters and about 1.22 meters, or between about 25 millimeters and about 300 millimeters.

The light guide plate 105 may comprise a wide range of materials that provide the desired optical properties. In some embodiments, the light guide plate 105 may include an amorphous inorganic material (e.g., glass), a crystalline material (e.g., sapphire, single or polycrystalline alumina, spinel (MgAl)₂O₄) Quartz), or a polymer. Embodiments of suitable polymers include, but are not limited to, the following items and copolymers and mixtures thereof: thermoplastics (including Polystyrene (PS), Polycarbonate (PC)), polyesters (including polyethylene terephthalate (PET)), polyolefins (including Polyethylene (PE), polyvinyl chloride (PVC)), acrylic polymers (including Polymethylmethacrylate (PMMA), Thermoplastic Polyurethanes (TPU), Polyetherimides (PEI), epoxies), and silicones (including Polydimethylsiloxane (PDMS)). Embodiments of glasses (which may be strengthened or non-strengthened and may be free of or contain lithium oxide) include soda lime glass, alkali aluminosilicate glass, alkali borosilicate glass, and alkali aluminoborosilicate glass. As used herein, the term "strengthened," when applied to a substrate (e.g., glass or another transparent layer), may refer to a substrate that has been chemically strengthened (e.g., chemically strengthened by ion exchanging larger ions with smaller ions in the surface of the substrate). However, other strengthening methods known in the art (e.g., thermal tempering, or creating compressive stress and central tension regions using a mismatch in thermal expansion coefficients between portions of the substrate) may also be utilized to form a strengthened substrate.

Referring first to fig. 1, the second major surface 111 of the light guide plate 105 includes a plurality of grooves 117. Each of the plurality of channels 117 may include a first surface 119, a second surface 121 opposite the first surface, and a base 123. Referring generally to fig. 2 of fig. 1, various exemplary embodiments of the surface profile of one of the plurality of grooves 117 in accordance with various embodiments of the light device are depicted in fig. 2-7. In some embodiments, all of the plurality of grooves 117 may have the same surface profile. Alternatively, the surface profile of one of the plurality of grooves may be different from the surface profile of another of the plurality of grooves. For example, embodiments may combine one or more surface profiles described with respect to one of fig. 2-7 with one or more other surface profiles discussed with respect to another of fig. 2-7.

Fig. 2 illustrates an embodiment of the surface profile of the groove 117, which may include one or more of the shapes of the first surface 119, the second surface 121, and the base 123 shown. Throughout this disclosure, the maximum depth of the groove is defined as the distance between the second major surface 111 and the base of the light guide plate 105 along a direction perpendicular to the second major surface 111. For example, referring to fig. 2, the maximum depth 205 of the groove 117 is defined as the distance between the second major surface 111 of the light guide plate 105 and the base 123 of the corresponding groove 117 in the direction perpendicular to the second major surface 111 of the light guide plate 105. Throughout this disclosure, unless otherwise indicated, the maximum depth of the trench of each embodiment of the present disclosure may be about 50 microns or less, about 40 microns or less, or about 30 microns or less, between about 1 micron and about 50 microns, between about 5 microns and about 40 microns, or between about 10 microns and about 30 microns.

Also, throughout the disclosure, the groove width is defined as the maximum distance between a first point on the first surface of the groove and a second point on the first surface of the groove along a direction perpendicular to the elongated direction of the groove and parallel to the second major surface of the light guide plate 105, wherein the first point and the second point are as far apart as possible. For example, referring to fig. 2, the trench width 211 may be a distance between a first point on the first surface 119 and a second point on the second surface 121 of the corresponding trench 117 along a direction 212 perpendicular to an elongation direction 802 (refer to fig. 8) of the trench 117, where the first point and the second point are as far apart as possible. Likewise, the first width 213 may be associated with the first surface 119 and the second width 215 may be associated with the second surface 121. The first width 213 may be a distance between a first point on the first surface 119 and a second point on the first surface 119 along a direction 212 perpendicular to the elongation direction 802 (refer to fig. 8), wherein the first point and the second point are as far apart as possible. Likewise, the second width 215 may be a distance between a first point on the second surface 121 and a second point on the second surface 121 along the direction 212 perpendicular to the elongation direction 802 (refer to fig. 8), wherein the first point and the second point are as far apart as possible. In some embodiments, as shown in fig. 2, a sum of a first width 213 associated with the first surface 119 and a second width 215 associated with the second surface 121 may be approximately equal to the trench width 211 of the corresponding trench 117.

In some embodiments, the first surface 119 of the trench 117 may include a first convex portion 201. Throughout this disclosure, the tangent angle (i.e., the angle tangent to a portion) is measured with respect to a direction perpendicular to the second major face 111 of the light guide plate 105. The first convex surface portion 201 may have a tangent angle that monotonically increases from a first point closer to the second major surface 111 of the light guide plate 105 to a second point closer to the base 123 of the corresponding groove 117, and the tangent angle at the second point is closer to 0 ° than the tangent angle at the first point. In further embodiments, the angle tangent to a first point closer to the second major face 111 of the light guide plate 105 may be about 90 °, and the angle tangent to a second point closer to the base 123 of the corresponding groove 117 may be about 0 °. In other embodiments, the angle tangent to a point on the first convex portion 201 may continuously increase as the selected point moves closer to the second major surface 111 of the light guide plate 105. Throughout the disclosure, monotonically increasing amounts never decrease, while monotonically decreasing amounts never increase.

Also, a portion of the light guide plate 105 bounded by the first convex portion 201 of the first surface 119 of the groove 117 may have the following properties: any two points in the first convex portion 201 may be connected by a line that is located entirely within the first convex portion 201 and does not intersect the first surface 119 of the corresponding groove 117. In some embodiments, the first convex portion 201 may have a maximum depth 207. Throughout this disclosure, the maximum depth of the convex portion is the maximum distance between a first point on the convex portion and a second point on the convex portion in a direction perpendicular to the second major surface 111 of the light guide plate 105, where the first point and the second point are as far apart as possible. Referring to fig. 2, the maximum depth 207 of the first convex portion may correspond to a maximum distance between two points in the first convex portion 201 of the first surface 119 in a direction perpendicular to the second major face 111, where the first point and the second point are as far apart as possible. As shown in fig. 2, in some embodiments, the first convex portion 201 may include the entire first surface 119 of the trench 117, however in other embodiments, the first convex portion 201 may also include less than the entire first surface. The maximum depth 207 of the first convex portion 201 may be the same along the length of the groove 117 (perpendicular to the surface profile shown in fig. 2). As further illustrated, in some embodiments, the maximum depth 207 of the first convex portion 201 may be substantially the same as the maximum depth 205 of the trench 117, however, in other embodiments, the maximum depth 207 of the first convex portion 201 may also be less than the maximum depth 205 of the trench 117. In other further embodiments, the second surface 121 may include a second convex portion 203, which may have similar or identical features to the first convex portion 201 discussed above. For example, as shown in fig. 2, in some embodiments, second convex portion 203 may comprise a mirror image of first convex portion 201. As shown in fig. 2, in some embodiments, the second convex portion 203 may include the entire second surface 121 of the groove 117, however in other embodiments, the second convex portion may also include less than the entire second surface. In yet further embodiments, the first convex portion 201 and the second convex portion 203 of the corresponding groove 117 may be symmetrically disposed about a plane bisecting the base 123 of the groove 117. Throughout this disclosure, the width of the convex portion is defined as the maximum distance between a first point on the convex portion and a second point on the convex portion in a direction perpendicular to the direction of elongation 802 (see fig. 8) and parallel to the first major face 109, where the first point and the second point are as far apart as possible.

The first and second convex portions 201, 203 may be provided with a depth angle, which may be the same as shown, although other depth angles may be provided in further embodiments. The depth angle 217 of the first convex portion 201 will be described, it being understood that such description may also apply to the depth angle of the second convex portion 203. For example, referring to fig. 2, the first convex portion 201 of the first surface 119 of the trench may be characterized by a depth angle 217. Throughout the disclosure, the depth angle of the convex portion of the surface of the groove is defined as an angle of tangency in the convex portion from a second point of the convex portion closest to the second major surface 111 of the light guide plate 105 with respect to a direction perpendicular to the second major surface 111 of the light guide plate 105The first point is 29.2% of the maximum depth of the convex portion of the groove, measured at the first point. 29.2% of the maximum depth of the convex part (i.e. 1-2)^-1/2Expressed in percentage) corresponds to a position at which the tangent angle would be 45 deg. with respect to a direction perpendicular to the second major face 111 when the surface profile of the convex portion includes a radius of curvature (see, for example, fig. 3). Referring to fig. 2, the depth angle 217 of the first convex portion 201 is an angle of tangency with respect to a direction perpendicular to the second major surface 111 of the light guide plate 105, measured from the second major surface 111 of the light guide plate 105 at a point 209 on the first convex portion 201 of the first surface 119, the point 209 being located at 29.2% of the maximum depth 207 of the first convex portion 201, since the first convex portion 201 is shown as including the entire first surface 119 of the groove 117. In some embodiments, the depth angle 217 may be the same as an angle between a line perpendicular to the second major surface 111 of the light guide plate 105 and a line having a slope equal to an average slope of the first convex portion 201 of the first surface 119. In further embodiments, the first convex portion 201 may include the entire first surface 119, and the average slope of the first convex portion 201 may be equal to the maximum depth 205 of the groove 117 divided by the first width 213 of the first surface 119 of the corresponding groove 117.

Within various embodiments of the trenches of the present disclosure, unless otherwise indicated, the depth angle of the first convex portion (e.g., the depth angle 217, 619, 623, 721 of the first convex portion 201, 607, 707 of the corresponding trench 117, 701 shown in fig. 2 and 6-7) may be about 10 ° or greater, about 20 ° or greater, about 30 ° or greater, about 35 ° or greater, about 55 ° or less, about 50 ° or less, between about 10 ° and about 55 °, between about 20 ° and about 55 °, between about 10 ° and about 50 °, between about 20 ° and about 50 °, between 30 ° and about 50 °, or between about 35 ° and about 50 °. In other embodiments, the depth angle of any of the embodiments of the grooves of the present disclosure may be about 80 ° or less, about 70 ° or less, about 60 ° or less, about 55 ° or less, or about 50 ° or less, unless otherwise indicated. In yet other embodiments, unless otherwise indicated, the depth angle of any of the embodiments of the grooves of the present disclosure may be between about 0 ° and about 80 °, between about 10 ° and about 60 °, between about 10 ° and about 55 °, between about 10 ° and about 50 °, between about 30 ° and about 60 °, between about 30 ° and about 55 °, between about 30 ° and about 50 °, between about 35 ° and about 55 °, or between about 35 ° and about 50 °. In further embodiments, the depth angle of the second convex portion (e.g., the second convex portion 121, 511, 609 of the corresponding groove 117, 501, 601 shown in fig. 2 and 5-6) may be between about 1 ° and about 55 °, between about 10 ° and about 55 °, between about 20 ° and about 55 °, between about 10 ° and about 50 °, between about 20 ° and about 50 °, between 30 ° and about 50 °, or between about 35 ° and about 50 °.

Fig. 3 depicts another embodiment of the surface profile of the trench 301, which may include one or more of the shapes of the first surface 303, the second surface 305, and the base 307 shown. In some embodiments, the first surface 303 may include a convex portion 309. In some embodiments, the convex portion 309 of the trench 301 may be the same as the first convex portion 201 of the trench 117 discussed above. In further embodiments, as shown, the convex portion 309 of the first surface 303 of the groove 301 may include a radius of curvature 319, wherein the convex portion 309 includes a cylindrical first surface 303. In such embodiments, all points on the surface profile of the convex portion 309 of the first surface 303 may be equidistant from a common point within the light guide plate 105, as shown in fig. 3. In some further embodiments, the radius of curvature 319 may be the same along the elongation direction 802 (see fig. 8), wherein the convex portion 309 of the first surface 303 comprises a cylinder. In other further embodiments, the radius of curvature 319 may change (e.g., monotonically change) along the direction of elongation 802 (see fig. 8). In still other further embodiments where the convex portion 309 includes the entire first surface 303, the first width 313 of the first surface 303 of the groove 301 may be the same as the maximum depth 311 of the corresponding groove 301 and the radius of curvature 319 of the convex portion 309. In such embodiments, the depth angle of the convex portion 309 may be about 45 ° or between about 40 ° and about 50 °. The maximum depth of the convex portion 309 may be the same along the length of the trench 301 (perpendicular to the surface profile shown in fig. 3).

As further illustrated in fig. 3, the second surface 305 may include an inclined portion 306. As shown, embodiments of the second surface 305 of the angled portion 306 may include a substantially planar surface. As shown, in some embodiments, the inclined portion 306 may extend from the second major surface 111 of the light guide plate 105 toward the base portion 307 of the groove 301. Throughout this disclosure, the depth angle of the inclined portion may be defined as an angle between the corresponding surface and a direction perpendicular to the second major surface 111 of the light guide plate 105. For example, as shown in fig. 3, the depth angle 317 of the inclined portion 306 of the second surface 305 of the groove 301 may be an angle between a direction perpendicular to the second major surface 111 of the light guide plate 105 and the inclined portion 306. In some embodiments, the depth angle 317 of the sloped portion 306 may be between about 0 ° and about 80 °, between about 0 ° and about 60 °, between about 0 ° and about 50 °, between about 10 ° and about 80 °, between about 10 ° and about 60 °, or between about 10 ° and about 50 °. Throughout this disclosure, the maximum depth of the inclined portion may be defined as the maximum distance between two points having the same tangent angle on the second surface 305 in the inclined portion 306 in a direction perpendicular to the second major face 111, where the first point is as far away from the second point as possible. The maximum depth of the sloped portion may be the same along the length of the trench 301 (perpendicular to the surface profile shown in fig. 3). Throughout this disclosure, the width of the angled portion is defined as the maximum distance between a first point on the angled portion and a second point on the angled portion in a direction perpendicular to the direction of elongation 802 (see fig. 8) and parallel to the first major face 109, where the first point and the second point are as far apart as possible. In some embodiments, as shown in fig. 3, the sum of the first width 313 of the first surface 303 and the second width 315 associated with the second surface 305 may be approximately equal to the trench width 312 of the corresponding trench 301.

Fig. 4 depicts another embodiment of the surface profile of the trench 401, which may include one or more of the shapes of the first surface 403, the second surface 405, and the base 411 shown. In some embodiments, first surface 403 may include convex portions 407 and second surface 405 may include concave portions 409. In some embodiments, the convex portion 407 of the trench 401 may be the same as the convex portion 309 of the trench 301 or the first convex portion 201 of the trench 117 discussed above. As such, the convex portions 407 may have a maximum depth associated therewith, and the maximum depth may be the same along the length of the trench 401 (perpendicular to the surface profile shown in fig. 4). The concave portions 409 of the grooves 401 may have a tangent angle that monotonically increases (i.e., never decreases) from a first point closer to the second major face 111 of the light guide plate 105 to a second point closer to the base 411 of the corresponding groove 401, meaning that the tangent angle at the first point is closer to 0 ° than the tangent angle at the second point. Also, a portion of the light guide plate 105 bounded by the concave portion 409 may not have the following properties: any two points in the portions may be connected by a line located entirely within the concave portions 409 of the second surface 405 of the trench 401, meaning that some such lines will intersect the concave portions 409 of the second surface 405.

Throughout this disclosure, the maximum depth of the concave portion is a maximum distance between a first point on the concave portion and a second point on the concave portion in a direction perpendicular to the second major surface of the light guide plate, wherein the first point and the second point are as far apart as possible. Referring to fig. 4, the concave portion 409 may have a maximum depth 417 associated therewith, which may correspond to a distance between two points on the concave portion 409 of the second surface 405 in a direction perpendicular to the second major face 111, wherein the points are as far apart as possible. As shown in fig. 4, in some embodiments, the concave portion 409 may include the entire second surface 405 of the trench 401, although in other embodiments, the concave portion may also include less than the entire second surface. The maximum depth of the concave portion 409 may be the same along the length of the trench 401 (perpendicular to the surface profile shown in fig. 4). As further illustrated, in some embodiments, the maximum depth 417 of the concave portion 409 may be substantially the same as the maximum depth of the trench 401, however, in other embodiments, the maximum depth 417 of the concave portion 409 may also be less than the maximum depth of the trench 401.

The concave portion 409 may include a depth angle 415. Throughout the disclosure, the depth angle of the concave portion of the surface of the groove is defined as an angle of tangent to a direction perpendicular to the second main face 111 of the light guide plate 105, the angle of tangent being measured from a second point of the concave portion closest to the base of the corresponding groove at a first point in the concave portion, the first point being 29.2% of the maximum depth of the concave portion. 29.2% of the maximum depth of the concave portion (i.e., 1-2)^-1/2Expressed in percentage) corresponds to a position at which the tangent angle would be 45 ° with respect to the direction perpendicular to the second main face 111 when the surface profile of the concave portion 409 includes a radius of curvature. Referring to fig. 4, the depth angle 415 of the concave portion 409 of the second surface 405 of the groove 401 is defined as an angle of tangency with respect to a direction perpendicular to the second major surface 111 of the light guide plate 105, measured from the base 411 of the corresponding groove 401 at a point 413 in the concave portion 409 of the second surface 405, the point 413 being located at 29.2% of the maximum depth of the groove 401, because the concave portion 409 is shown to include the entire second surface 405 of the groove 401. In some embodiments, the depth angle 415 of the concave portion 409 may be between about 0 ° and about 80 °, between about 0 ° and about 60 °, between about 0 ° and about 50 °, between about 30 ° and about 60 °, or between about 30 ° and about 50 °. Throughout this disclosure, the width of the concave portion is defined as the maximum distance between a first point on the concave portion and a second point on the concave portion in a direction perpendicular to the direction of elongation 802 (see fig. 8) and parallel to the first major face 109, where the first point and the second point are as far apart as possible.

Fig. 5 depicts another embodiment of the surface profile of the trench 501, which may include one or more of the shapes shown for the first surface 503, the second surface 505, and the base 513. The first surface 503 may include a first convex portion 507. In some embodiments, the first convex portion 507 of the trench 501 may be the same as the first convex portion 201 of the trench 117 or the convex portion 309 of the trench 301 discussed above. As such, the first convex portion 507 may have a maximum depth associated therewith, and the maximum depth may be the same along the length of the trench 501 (perpendicular to the surface profile shown in fig. 5).

As shown, the second surface 505 may comprise a compound shape that is not completely convex, not completely concave, and not completely inclined. In some embodiments, the composite shape may include a surface having at least two surfaces from the group of: a concave portion, a convex portion, and an inclined portion. For example, as shown in the illustrated embodiment, the second surface 505 may include a second convex portion 511 and a concave portion 509.

Similar to the convex portions of the other embodiments discussed above, the second convex portion 511 may have a width 517, a maximum depth 515, and a depth angle 519 measured using an orthonormal angle from a second point of the corresponding second convex portion 511 closest to the second major surface 111 of the light guide plate 105 at a first point 521 on the second convex portion 511 with respect to a direction perpendicular to the first major surface 109, the first point 521 being located at 29.2% of the maximum depth 515 of the corresponding second convex portion 511. The width 517 of the second convex portion 511 may be a distance between a first point on the second convex portion 511 and a second point on the second convex portion 511 of the corresponding trench 501 along the direction 212 perpendicular to the elongation direction 802 (refer to fig. 8), where the first point and the second point are as far apart as possible. In other embodiments, the width of the convex portion may be similarly defined. The maximum depth 515 of the second convex portion 511 may be the same along the length of the trench 501 (perpendicular to the surface profile shown in fig. 5). Also, at the maximum depth 515 of the second convex portion 511, the surface profile of the second surface 505 may include a inflection location where the second surface 505 transitions from the second convex portion 511 to the concave portion 509. As shown in fig. 5, the inflection locations may include inflection points on the surface profile. Further, the inflection position may extend as an inflection line along the elongation direction 802 (refer to fig. 8) of the corresponding trench 501, wherein the transition position may be located between the concave portion 509 and the second convex portion 511 of the second surface 505. In some embodiments, the inflection line may be parallel to the elongation direction 802 (refer to fig. 8) and/or the maximum depth 515 of the second convex portion 511 may be the same along the length of the trench 501. Although not shown, the transition locations may include linear contours, rather than points. For example, where the transition location includes an embodiment of a line in the elongation direction 802 (see fig. 8), the transition location may define a linear portion of the surface profile perpendicular to the elongation direction 802 (see fig. 8), such as a bevel or other transition surface that may extend along the length of the trench between the second convex portion 511 and the concave portion 509.

The concave portions 509 of the second surface 505 may be characterized in the manner described above for the other concave portions of the other embodiments. As shown in fig. 5, in some embodiments, the concave portion 509 may be closer to the base 513 of the trench 501 than the second convex portion 511. Although not shown, in other embodiments, the second convex portions 511 may be closer to the base 513 of the trench 501 than the concave portions 509. Although not shown, in other embodiments, the composite shape of the second surface may include one or more sloped portions that may be characterized in the manner described above for other surfaces 305 that include sloped portions. The one or more inclined portions (if provided) may be located closer to the base 513 of the trench 501 than the concave portion 509 and the second convex portion 511, between the concave portion 509 and the second convex portion 511, and/or closer to the second major face 111 than the concave portion 509 and the second convex portion 511. In yet other embodiments, the composite shape of the second surface 505 may include more than two distinct portions selected from one or more of a concave portion, a convex portion, or an inclined portion. For example, the second surface may comprise a convex portion sandwiched between two concave portions, or vice versa.

Fig. 6 depicts another embodiment of the surface profile of the groove 601, which may include one or more of the shapes of the first surface 603, second surface 605, and base 611 shown. In some embodiments, the first surface 603 may include a first convex portion 607 and the second surface 605 may include a second convex portion 609. The first convex portion 607 and/or the second convex portion 609 may include features similar or identical to the convex portions 201, 203, 309 of the grooves 117, 301 discussed above. The first convex portion 607 may be characterized by a first depth angle 619, as defined above. The second convex portion 609 may be characterized by a second depth angle 623.

The depth angle difference between the first depth angle 619 and the second depth angle 623 may be defined as the absolute value of the first depth angle 619 of the first convex portion 607 minus the second depth angle 623 of the second convex portion 609. In further embodiments, the difference may be about 5 ° or greater, about 10 ° or greater, about 15 ° or greater, between about 5 ° and about 45 °, between about 10 ° and about 40 °, or between about 15 ° and about 30 °. In other further embodiments, the difference may be about 5 ° or less, about 2 ° or less, or about 1 ° or less. In such embodiments, the first depth angle 619 and the second depth angle 623 may be about the same. Also, in some embodiments, the second convex portion 609 may include a mirror image of the first convex portion 607, or be arranged as discussed above with respect to fig. 2 for the first and second convex portions 201, 203 of the groove 117.

In some embodiments, the base 611 of the groove 601 includes a base surface 613 and an associated width 615 that extends between the first surface 603 and the second surface 605 in a direction parallel to the second major face 111. As depicted, in some embodiments, the base surface 613 may be flat, but may alternatively be curved (e.g., concave outward) in further embodiments. For example, as shown, the base surface 613 may comprise a substantially planar surface that may be substantially parallel to the second major face 111, although non-parallel orientations may also be provided in further embodiments. For example, in some embodiments, the base surface 613 may include at least one or more flat surfaces, wherein at least one of the flat surfaces includes an inclined portion that extends outwardly toward the second major face 111 in a direction from the first surface 603 toward the second surface 605. In some embodiments, the base surface 613 may comprise at least one or more flat surfaces, wherein at least one of the flat surfaces comprises an inclined portion extending inwardly away from the second major face 111 in a direction from the first surface 603 towards the second surface 605.

In some embodiments, the width 615 of the base surface 613 can be about 50 microns or less, about 30 microns or less, about 10 microns or less, about 5 microns or less, about 2 microns or less, or about 1 micron or less. In further embodiments, as shown in fig. 1-5, the base 123, 307, 411, 513 may include a sharp corner where the first surface 119, 303, 403, 503 meets the second surface 121, 305, 405, 505 of the corresponding trench 117, 301, 401, 501 at a sharp transition location. Likewise, the base 713 of the trench 701 discussed below with respect to fig. 7 may also include a sharp corner where the first surface 703 meets the second surface 705 at a transition location. In such embodiments, the sharp corners may form a sharp corner line along the length of the corresponding trench. Further, the width 615 of the base surface 613 of the sharp corner may be less than or equal to 1 micron, for example less than or equal to the surface roughness of the first and/or second surface of the corresponding trench 117, 301, 401, 501, 701. In other further embodiments, the first concave portion 201 of the first surface 119 may meet the second concave portion 203 of the second surface 121 at a base 123, which may optionally include sharp corners, as shown in fig. 2. In yet other further embodiments, the first surface 303, 403, 503 and the second surface 305, 405, 505 may meet at a base 307, 411, 513, which may optionally include a sharp corner as shown in fig. 3-5. Similar to the width 615 of the base surface 316, any of the embodiments of the present disclosure (e.g., fig. 2-5 and 7) can include a base having a width greater than the sharp corner, e.g., wherein the width is between about 1 micron and about 50 microns, between about 1 micron and about 30 microns, between about 1 micron and about 10 microns, or between about 1 micron and about 5 microns. In such embodiments where the width of the base is greater than the sharp angle, the width of the base surface may be greater than the surface roughness of the corresponding trench.

As shown in fig. 6, the difference between the trench width 629 and the sum of the first width 625 of the first surface 603 and the second width 627 of the second surface 605 of the corresponding trench 601 may be about the width 615 of the base 611. The trench width 629, the first width 625, and the second width 627 may be defined in the same manner as the trench width 211, the first width 213, and the second width 215, respectively, are defined for fig. 2. In further embodiments, the first surface 603 may include a first convex portion 607 and the second surface 605 may include a second convex portion 609, as shown in fig. 6. In other further embodiments, the first surface 603 may include a first convex portion 607, and the second surface may include a concave portion. In yet other further embodiments, the first surface 603 may include a first convex portion 607, and the second surface may include an inclined portion. In yet other embodiments, the first surface 603 may include a first convex portion 607 and the second surface 605 may include a compound shape, as described for the trench 501 discussed above. The first convex portion 607 may have a first maximum depth associated therewith, and the first maximum depth may be the same along the length of the groove 601; the second convex portion 609 may have a second maximum depth associated with it, and the second maximum depth may be the same along the length of the groove 601; and the length of the groove 601 may be perpendicular to the surface profile shown in fig. 6.

Fig. 7 illustrates another embodiment of the surface profile of the trench 701, which may include one or more of the shapes of the first surface 703, the second surface 705, and the base 611. As shown, the first surface 703 may include a compound shape that may be a mirror image of the second surface 505 of the trench 501 or include features similar or identical to the compound shape of the second surface 505 of the trench 501 of fig. 5 discussed above. For example, the first surface 703 of the trench may include a convex portion 707 having a depth angle 721 that is similar or identical to the second convex portion 511 of the trench 501 and the corresponding depth angle 519 discussed above with respect to fig. 5. The first surface 703 may include a convex portion 707 and at least one non-convex portion selected from a concave portion 709 and an inclined portion, and may further include another convex portion. For example, in the depicted embodiment, the non-convex portions may include the depicted concave portions 509, which may be similar or identical to the concave portions 509 of the trenches 501 discussed above with respect to fig. 5.

In further embodiments, the second surface 705 may include an inclined portion 711, as shown in fig. 7. The sloped portion 711 (if provided) may be similar or identical to the sloped portion 306 discussed with respect to the trench 301 of fig. 3 discussed above. In further embodiments, although not shown, the second surface 705 of the trench 701 may also include convex portions similar to or the same as the first convex portions 201, 309 discussed above with respect to the trenches 117, 301 of fig. 2 and 3. In other further embodiments, although not shown, the second surface 705 of the trench 701 may also include concave portions similar to or the same as the concave portions 409 discussed above for the trench 401 of fig. 4. In yet other further embodiments, although not shown, the second surface 705 of the trench 701 may also include a composite shape similar to or the same as the composite shape of the second surface 505 of the trench 501 discussed above. In some embodiments, the compound shape of the first surface 703 may be similar to the compound shape of the second surface 705. As shown, the base 713 of the trench 701 may include a sharp corner. Alternatively, as previously described, the base 713 of the trench 701 may include any other type of base that is not a sharp corner as discussed above. Also, the first convex portions 711 may have a first maximum depth associated therewith, and the first maximum depth may be the same along the length of the trench 701; the inclined portion 711 may have a second maximum depth associated with the second convex portion, and the second maximum depth may be the same along the length of the trench 701; and the length of the trench 701 may be perpendicular to the surface profile shown in fig. 7.

Grooves including any of the above surface profiles may be used in various embodiments of the light devices of the present disclosure. A number of different methods may be used to form the grooves in the light guide plate 105, including diamond turning, laser ablation, laser etching, chemical etching, molding, thermal embossing, or printing.

Diamond engraving can be used to create very precise grooves in virtually any light guide plate material. As such, diamond turning may be used to produce any of the embodiments of the base discussed herein (e.g., a base comprising sharp corners) and any of the embodiments of the surface profile of the trench surface discussed herein (e.g., a convex portion or a concave portion comprising the entire trench first surface). However, in some applications, diamond turning can be an expensive process because it requires diamond tipped tools and very accurate machining (e.g., with very accurate Computer Numerical Control (CNC) machines).

Laser ablation may be used to remove a portion of the light guide plate with a laser to form the trench. The laser may include a pump-detection system, optical filters, lenses, mirrors, and gratings that may be used to stretch, compress, amplify, or filter the pulses. The wavelength of the laser light may be tuned such that the material of the light guide plate is opaque at said optical wavelength, meaning that the material will absorb some of the energy emitted by the laser light. For example, borosilicate glass may be ablated using ultraviolet or visible wavelength laser pulses. A high intensity pulse of laser light is emitted and characterized by an energy density and duration. Energy density may be defined as the time-integrated fluence of the radiation emitted by the laser in a pulse at a surface cross-section, and may have a W/cm²The unit of (c). Ablation typically occurs when the energy density is greater than a critical value, which depends on the light guide plate material and the nature of the laser device. Each pulse may have a very short duration, such as about 1 microsecond or less, 10 nanoseconds or less, 5 nanoseconds or less, 1 nanosecond or less, about 500 femtoseconds or less, about 200 femtoseconds or less, or about 100 femtoseconds or less. Each pulse may remove a predetermined amount of material (e.g., 0.04 μm) via ablation (e.g., absorption followed by a thermalization mechanism, such as evaporation, ionization, melting, or explosion) in a region targeted by the laser with a certain beam radiusMeters per pulse). In general, the pulse duration, number of pulses, and pulse repetition rate may be adjusted to control the amount of material removed and the pattern formed in the light guide plate material. Shorter pulses and slower repetition rates may be associated with fewer cracks or even no cracks in the light guide plate material. Laser ablation may be performed in vacuum, in air, or in the presence of an inert gas. Depending on the selected parameters, laser ablation may produce a trench comprising a compound shape with the base comprising a flat bottom or surface, with the convex portion closer to the second major face of the light guide plate and the concave portion closer to the base of the trench. Additional control over the resulting trench shape can be obtained using plasma assisted laser ablation or flow assisted laser ablation.

Longer laser pulses may be used to create the trenches via laser etching. One method may allow a laser to melt a portion of the light guide plate 105 material. Generally, an infrared laser, such as a carbon dioxide or YAG (Yttrium aluminum garnet doped neodymium) laser, is used to heat the light guide plate 105 material in a preselected region. Another method for creating trenches using a laser is a form of laser etching known as Laser Induced Backside Wet Etching (LIBWE). In LIBWE, selected portions of the second major surface 111 of the light guide plate 105 may be contacted with a thin liquid layer that absorbs the pulsed energy from the laser to etch the light guide plate 105. LIBWE can effectively etch crack-free trenches in transparent materials with high accuracy. Various organic dyes and inorganic pigments can be used as the photoresist. Either form of laser etching may result in smooth irregularities in the surface of the trench. Further, a flat base surface may be formed in some of the trenches.

Chemical etching may be used to remove a portion of the light guide plate to form the trench by controlling the position and exposure time for various chemicals. To make some embodiments, a removable mask may be deposited on a portion of the second major surface 111 of the light guide plate 105 in an area that would be part of the groove. Next, the light guide plate 105 may be placed into a controlled chamber where it is exposed to an etchant. The exposure time and concentration profile of the etchant can control the shape of the resulting trench. After etching, the mask may be removed. In some embodiments, the mask may limit the area etched by the etchant. For example, the mask may include an amount of boron or a polymer. In other embodiments, it may not be necessary to deposit a mask on the second major surface 111 of the light guide plate 105. Rather, a mask may be used to shape the distribution of the etchant. In some cases, no mask may be needed at all. In some processes, the etchant may be a liquid that may effectively etch the material of the light guide plate 105 but not the material of the mask. For example, the etchant may be an acid (like HF) or a base (like NaOH). In other embodiments, the etchant may be applied as a gas. For example, HF gas may be applied in a controlled chamber. In yet other embodiments, the etchant may be a plasma. In yet other embodiments, the etchant may be generated by a light source. When a mask is used, it may be removed via several different techniques, depending on the composition of the mask. For example, the mask may be oxidized by plasma exposure. Alternatively, the mask may be removed by ashing. Still further, a solvent, such as 1-methyl-2-pyrrolidone (NMP), may be used to remove the mask. Using such a chemical etching procedure, a rounded groove base or composite surface can be created, with the concave portions closer to the base. If the etchant exposure is long, over-etching may occur, creating a trench shape that turns back on itself before reaching the trench base.

The grooves may also be formed in the light guide plate by molding, thermal embossing, or printing. For example, the molten material may be poured into a mold having a desired surface profile of the second major surface 111 of the light guide plate 105. Once cooled, the light guide plate 105 may be removed from the mold and the first major face may be machined. In other embodiments, the light guide plate 105 may be thermally embossed. Alternatively, the light guide plate 105 may be ink-jetted or three-dimensionally (3D) printed to form a desired groove shape. In one embodiment, light guide plate 105 may be fabricated from a single material formed in a single molding or printing process. In another embodiment, a portion of the light guide plate 105 including the second major surface 111 may be molded or printed separately from the rest of the light guide plate 105. In further embodiments, a first portion of the light guide plate 105 including the second major surface 111 may comprise a different material than a second portion comprising the remainder of the light guide plate 105. In yet further embodiments, the first portion may include a polymer and the second portion may include an amorphous inorganic material or a crystalline material. It may be desirable to separately process the first and second portions of the light guide plate 105 to reduce overall processing costs. As such, molding may be desirable when cost is to be minimized.

Referring to fig. 1, an embodiment of the light device of any of the embodiments may comprise a light source 103, which may face a first edge 107 of the light guide plate 105. In some embodiments, the first surface 119, 303, 403, 503, 603, 703 may be closer to the light source 103 than the second surface 121, 305, 405, 505, 605, 705 of the corresponding trench 117, 301, 401, 501, 601, 701, as shown in fig. 1. In some embodiments, the light source 103 may comprise a light emitting lamp, such as an array of Light Emitting Diodes (LEDs). In further embodiments, the light source 103 may comprise an incandescent lamp or a discharge lamp. The light source 103 may comprise a light emitting diode, a bulb, or a laser. Exemplary diodes include, but are not limited to, Light Emitting Diodes (LEDs) comprising inorganic semiconductor materials, small molecule Organic Light Emitting Diodes (OLEDs), and Polymer Light Emitting Diodes (PLEDs). Examples of bulbs include, but are not limited to, incandescent bulbs (including tungsten filament bulbs), gas-filled discharge tubes (including fluorescent, neon, argon, xenon lamps), and high-energy arc discharge lamps. Examples of lasers include, but are not limited to, helium-neon, argon, krypton, ruby, copper vapor, gold vapor, manganese vapor, and dye lasers. In some embodiments, in embodiments requiring a compact shape and low power consumption, a diode may be preferred as the light source 103. In other embodiments, fluorescent light sources may be preferred where cost is to be minimized. In further embodiments, the light source 103 may comprise a light pipe configured to deliver light to the first edge 107 of the light guide plate 105. For example, the light source 103 may include an optical fiber to deliver light to the first edge 107. In further embodiments, the light source 103 may be positioned to deliver light to the first edge 107.

Fig. 8 depicts an exemplary embodiment of a cross-section taken along line 8-8 in fig. 1, showing a direction 803 of light emitted from the light source 103 and traveling toward the first edge 107. In some embodiments, the light source 103 may be positioned to emit light at least partially in a direction 803 perpendicular to the first edge 107, although in other embodiments, a tilted (e.g., non-perpendicular) direction is also possible. In some embodiments, a first trench 117, 301, 401, 501, 601, 701 may be spaced apart from an adjacent second trench 811 by a first spacing 817. In further embodiments, the first spacing 817 may be about 5 microns or greater, about 10 microns or greater, about 20 microns or greater, about 50 microns or greater, or about 100 microns or greater. In other further embodiments, the first spacing 817 may be about 5 millimeters or less, about 2.5 millimeters or less, about 1 millimeter or less, about 500 microns or less, about 200 microns or less, about 100 microns or less, or about 50 microns or less. In still other further embodiments, the first spacing 817 may be between about 5 microns and about 5 millimeters, between about 5 microns and about 2.5 millimeters, between about 10 microns and about 1 millimeter, between about 20 microns and about 1 millimeter, between about 50 microns and about 500 microns, or between about 20 microns and about 200 microns. In some embodiments, the grooves 117, 301, 401, 501, 601, 701, 811 may comprise a length extending in an elongation direction 802, which may be substantially parallel to the first edge 107 and perpendicular to the direction of the length 112 of the light guide plate 105.

In other embodiments, a second spacing 819 between a second pair of adjacent trenches may be defined. In further embodiments, a first spacing 817 between a first pair of adjacent trenches (e.g., 117, 301, 401, 501, 601, 701, 811) may be the same as a second spacing 819 between a second pair of adjacent trenches. In other further embodiments, the first spacing 817 may be greater than the second spacing 819 when the first pair of adjacent grooves 117, 301, 401, 501, 601, 701, 811 is closer to the first edge 107 of the light guide plate 105 than the second pair of adjacent grooves. Such a spacing pattern provides the technical benefit of distributing light evenly between the trenches 117, 301, 401, 501, 601, 701, 801, as the trenches 117, 301, 401, 501, 601, 701, 811 are denser where there is lower light intensity. While not wishing to be bound by existing theory, the light intensity decreases without any object with the inverse square of the distance from the light source; in the light guide plate 105, the light intensity may exponentially decrease with distance as the light reflects off the plurality of grooves 117 and out of the light guide plate 105. In yet further embodiments, the relationship between the spacing of pairs of adjacent trenches may be valid for all adjacent trench spacings. In other words, the spacing 817, 819 between pairs of adjacent grooves along the length 112 of the light guide plate 105 may decrease as the distance of adjacent groove pairs from the first edge 107 increases. This spacing may range between about 5 microns to about 5 millimeters, between about 10 microns to about 2.5 millimeters, between about 10 microns and about 1 millimeter, between about 10 microns and about 500 microns, between about 20 microns and about 1 millimeter, or between about 20 microns and about 500 microns. In some embodiments, the maximum depth of each of the plurality of grooves 117 may increase as the distance from the corresponding groove to the light source 103 increases. In other embodiments, the maximum depth of each groove of the plurality of grooves 117 may increase as the distance from the corresponding groove to the first edge 107 of the light guide plate 105 increases. In other embodiments, the depth angle of at least one surface of each of the plurality of grooves 117 may vary as a function of the distance between the corresponding groove and the first edge 107 of the light guide plate 105. In some further embodiments, the depth angle may increase linearly as the distance between the corresponding groove and the first edge 107 of the light guide plate 105 increases. In other further embodiments, the depth angle may decrease linearly as the distance between the corresponding groove and the first edge 107 of the light guide plate 105 increases.

In further embodiments, as shown in fig. 8, the length of one or more of the grooves 117, 301, 401, 501, 601, 701, 811 may be equal to or greater than the width 813 of the light guide plate 105. For example, in some embodiments where the grooves extend in the elongate direction 802 of the width 813, the length of one or more of the grooves may be equal to the width 813 of the light guide plate 105. Alternatively, in some embodiments where the grooves extend in a direction of the elongation direction 802 that is not equal to the width 813, the length of the grooves may be greater than the width 813 of the light guide plate 105. In some embodiments, the length of one or more of the grooves extends through at least one or both of the third and fourth edges 807, 809. For example, as shown in fig. 8, all of the grooves extend continuously and uninterrupted from the third edge 807 to the fourth edge 809 and through the third and fourth edges. In some embodiments, the length of one or more of the grooves may be about 50 microns or greater, about 100 microns or greater, about 200 microns or greater, or about 500 microns or greater, about 1 millimeter or greater, about 10 millimeters or greater, about 100 millimeters or greater, about 500 millimeters or greater, about 1000 millimeters or greater, or about 2000 millimeters or greater.

As discussed above with respect to fig. 8, the length of one or more of the grooves may be about 100% of the width 813 of the light guide plate and may extend through one or both of the third and fourth edges 807, 809. Fig. 9 depicts an alternative embodiment in which one or more of the grooves optionally extend through only one of the third and fourth edges 807, 809, and in some embodiments, less than the width 813 of the light guide plate 105, as shown. For example, in embodiments where one or more of the grooves extend in the direction of the width 813, the grooves 117, 301, 401, 501, 601, 701, 811 may include a groove length 912 that may extend between about 10% and about 100%, between about 20% and about 90%, between about 25% and about 75%, between about 10% and about 50%, or between about 15% and about 25% of the width 813 of the light guide plate 105.

As further illustrated in fig. 9, in some embodiments, the at least one grooved path 903a, 903b may comprise one or more grooves on the path. Throughout this disclosure, a groove is considered to be located on a groove path when the length of the corresponding groove extends along the groove path and the base of the corresponding groove is positioned on the groove path. In embodiments where multiple grooves are located on a common path, the grooves may be spaced along the groove path. In further embodiments, the trench paths 903a, 903b may be parallel to each other and/or may comprise substantially straight paths. For example, fig. 9 depicts straight grooved paths 903a, 903b that are parallel with respect to each other and may be parallel with the first edge 107 of the light guide plate 105, as shown. Also, each trench path may include a plurality of aligned trenches, however in other embodiments, one or more trench paths may include only a single trench. For example, fig. 9 depicts a first trench path 903a and a second trench path 903b, each trench path including a corresponding plurality of trenches 909a, 909b located on the respective trench paths 903a, 903b and spaced apart from each other along the respective trench paths 903a, 903 b. In practice, the plurality of grooves 909a on the first groove path 903a may be spaced apart from each other by a distance 911. In some embodiments, the distance 911 between each trench in the first trench path 903a may be the same, although in other embodiments, different distances 911 may also be provided.

In further embodiments, the plurality of grooves 909b of the second groove path 903b can be located on the second groove path 903b and spaced apart from each other by a distance 913. In some embodiments, the distance 911 between each trench in the first trench path 903a may be the same, although in other embodiments, different distances may also be provided. In some embodiments, the distance 913 between each trench in the second trench path 903b may be the same, although in other embodiments, different distances may also be provided. Also, the distance 911 between the grooves 909a of the first groove path 903a may be the same as or different from the distance 913 between the grooves 909b of the second groove path 903 b. The distance 911, 913 between trenches 909a, 909b can be about 10 microns or greater, about 20 microns or greater, about 50 microns or greater, or about 100 microns or greater. In other further embodiments, the distance 911, 913 between the grooves 909a, 909b can be about 100 millimeters or less, about 50 millimeters or less, about 25 millimeters or less, about 10 millimeters or less, about 5 millimeters or less, about 2.5 millimeters or less, about 1 millimeter or less, or about 500 micrometers or less. In still other further embodiments, the distances 911, 913 may be between about 10 microns and about 100 millimeters, between about 10 microns and about 50 millimeters, between about 10 microns and about 25 millimeters, between about 10 microns and about 10 millimeters, between about 10 microns and about 2.5 millimeters, between about 20 microns and about 2.5 millimeters, between about 50 microns and about 2.5 millimeters, between about 100 microns and about 2.5 millimeters, between about 20 microns and about 1 millimeter, between about 50 microns and about 1 millimeter, or between about 50 microns and about 500 microns.

The groove length 912 of each of the plurality of grooves 909a and/or 909b may be the same or different from each other. Further, the profile of trenches 909a, 909b, and 811 of fig. 8 and 9 can include the profile of any of trenches 117, 301, 401, 501, 601, or 701, or other trenches in accordance with the present disclosure.

As further shown, the spacing 915 between the trench paths 903a, 903b may or may not have the same attributes as the spacings 817, 819 discussed above in connection with fig. 8. In other further embodiments, one or more grooves 909a of a first groove path 903a may be staggered in the direction of the width 813 of the light guide plate 105 relative to one or more grooves 909b of an adjacent second groove path 903b such that the spacing defined by the distance 911 between adjacent pairs of grooves 909a of a first groove path 903a is not aligned with the spacing defined by the distance 913 between adjacent pairs of grooves 909b of a second groove path 903b along the direction of the length 112 of the light guide plate 105 and/or perpendicular to the first edge 107 of the first light guide plate. Such a staggered design may provide the following technical benefits: the light exiting the light guide plate 105 is more evenly distributed along the length 112 of the light guide plate 105 than if the grooves 909a, 909b were aligned between the groove paths 903a, 903 b.

Referring back to fig. 1, in some embodiments, light device 101 may optionally further comprise a display 115. In such embodiments, the display 115 may be a Liquid Crystal Display (LCD) or similar display that may benefit from external illumination. As further depicted in fig. 1, in some embodiments, the display 115 may include a reflector 113. In such embodiments, the reflector 113 may comprise an essentially reflective material, such as aluminum, steel, or silver. In other such embodiments, the reflector 113 may comprise a material (e.g., polyethylene terephthalate (PET) or Polycarbonate (PC)) that is reflective when disposed in proximity to another material having a different index of refraction in the light device 101. In some embodiments, the reflector 113 may include an average reflectivity of about 90% or greater, about 95% or greater, about 96% or greater, or about 98% or greater over a wavelength range from about 400nm to about 700 nm. In some embodiments, the reflector 113 may face the second major surface 111 of the light guide plate 105, as shown in fig. 1.

As configured in fig. 1, the display 115 may be backlit by light from the light source 103 exiting the light guide plate 105. In other embodiments, the light guide plate 105 may be located on other sides of the display 115 to front illuminate the display 115. Also, the light source 103 is shown facing the first edge 107 of the light guide plate 105, such that the light guide plate 105 is edge-lit. In other embodiments, the light guide plate 105 may be backlit by a light source positioned between the second major surface 111 of the light guide plate 105 and the reflector 113 or in place of the reflector 113. In yet other implementations, the light source 103 may face another edge of the light guide plate 105 (e.g., the second edge 110, the third edge 807, and/or the fourth edge 809).

As used to describe fig. 10-13, the term "vertical" refers to a direction from the light source 103 toward the first edge 107 of the light guide plate 105, while "horizontal" refers to a direction perpendicular to the "vertical" direction and a direction orthogonal to the first major surface 109 of the light guide plate 105.

FIG. 10 shows leaving the light guide plate according to embodiments described herein when the second major face has an inclined grooveAn angular distribution of light of the first major face, the slanted grooves having a maximum depth of 5 microns for different depth angles. For each sub-diagram, the x-axis (i.e. horizontal axis) is the horizontal angle with respect to the direction orthogonal to the first main face of the light guide plate, and the y-axis (i.e. vertical axis) is the vertical angle with respect to the direction orthogonal to the first main face of the light guide plate. Plotted gray value and in W/m²The radiance in units of white to black corresponds to 0W/m for white²Black is the maximum. The depth angle of each surface of the inclined groove is 35 °, 45 °, and 55 ° from the left side to the right side. For a depth angle of 35, the maximum radiance occurs at the bottom of the downward facing parabola arc between-30 to-20 on the vertical axis across the horizontal axis. For a depth angle of 45 deg., the peak radiance is localized in the band between-60 deg. to-30 deg. and 30 deg. to 60 deg. on the horizontal axis. For a depth angle of 55 deg., the bands are centered around-60 deg. on the horizontal axis and 60 deg. and slightly positive values on the vertical axis. In the vertical direction, the general trend is that for smaller depth angles (i.e., less than 35 ° (not shown)), the peak radiance is concentrated around-60 ° to-30 °, and the vertical angle increases with increasing depth angle. In the horizontal direction, the general trend is that the maximum radiance is concentrated for depth angles around 35 °, but the maximum radiance diverges away from depth angles of 35 ° towards-60 ° and 60 °.

Fig. 11 depicts the angular distribution of light exiting the first major surface of a light guide plate according to embodiments described herein when the second major surface has concave grooves with a maximum depth of 5 microns for different depth angles. For each sub-figure, the x-axis (horizontal axis) is a horizontal angle with respect to a direction orthogonal to the first main face of the light guide plate, and the y-axis (vertical axis) is a vertical angle with respect to a direction orthogonal to the first main face of the light guide plate. Plotted gray value and in W/m²The radiance in units of white to black corresponds to 0W/m for white²Black is the maximum. The depth angle of each surface of the concave groove is 35 °, 45 °, and 55 ° from the left side to the right side. Emissivity for a depth angle of 35 °Like a "U" turned upside down, with maximum intensity around-75 deg. vertically and 0 deg. horizontally. For a depth angle of 45 deg., the radiance is more closely clustered around the same maximum radiance location. For larger depth angles (e.g., 55), this tendency to localize at-75 ° vertically continues. For smaller depth angles (e.g., less than 35 °), the radiance is more diffuse and forms an "O" shape with very little radiance in the middle (i.e., near orthogonal angles).

Fig. 12 depicts the angular distribution of light exiting the first major face of a light guide plate according to embodiments described herein when the second major face has convex grooves with a maximum depth of 5 microns for different depth angles. For each sub-figure, the x-axis (horizontal axis) is a horizontal angle with respect to a direction orthogonal to the first main face of the light guide plate, and the y-axis (vertical axis) is a vertical angle with respect to a direction orthogonal to the first main face of the light guide plate. Plotted gray value and in W/m²The radiance in units of white to black corresponds to 0W/m for white²Black is the maximum. In the top column, the depth angle of each convex groove is 35 °, 45 °, and 55 ° from the left side to the right side. In the bottom row, the depth angle of each convex trench is 20 °, 25 °, and 30 °. For a depth angle of 35 deg., the radiance is highest in a rectangle between-30 deg. and 30 deg. in the vertical direction and between-60 deg. and 60 deg. in the horizontal direction. The maximum radiance appears to lie around the orthogonality in two directions (i.e., 0 °). For higher depth angles (e.g., 45 °), the radiance bifurcates into clusters-45 ° and around 45 ° horizontally, which eventually fan out at yet higher depth angles (e.g., 55 °) to form an upside-down "U" shape.

Of the examined trench designs, only the convex trench design has the maximum radiance in two directions near orthogonal. The following of fig. 12 shows the angular distribution of convex trenches with depth angles smaller than 35 °. For a depth angle of 30 deg., the radiance distribution is very similar to that of 35 deg., i.e., concentrated around normal incidence in the vertical direction and covering a wide band in the horizontal direction. For a depth angle of 25 deg., the shape of the distribution is approximately the same, but the intensity seems to be less than 30 deg.. For a depth angle of 30 deg., the intensity drops sharply. As such, a convex trench design with a depth angle between 25 ° and 45 ° appears to give maximum radiance at orthogonal angles in the vertical and horizontal directions. Also, such a gutter design will optimally illuminate the display for an observer with their eyes aligned in the horizontal direction of fig. 10-12 (i.e., perpendicular to the length of the gutter).

The emissivity behavior described for the convex grooves is unexpected. Other trench designs are not able to achieve comparable behavior at the same 5 micron trench size. Fig. 13 depicts the angular distribution of light exiting the first major face of a light guide plate according to embodiments described herein when the second major face has either of angled grooves or concave grooves, the grooves having a depth angle of 35 ° for different maximum depths. For each sub-figure, the x-axis (horizontal axis) is a horizontal angle with respect to a direction orthogonal to the first main face of the light guide plate, and the y-axis (vertical axis) is a vertical angle with respect to a direction orthogonal to the first main face of the light guide plate. For each column of subgraph, the plotted gray values are in W/m²The radiance in units of white to black corresponds to 0W/m for white²Black is the maximum. The left rows correspond to angled grooves and the right rows correspond to concave grooves. From top to bottom, each column corresponds to a maximum depth of 50 microns, 250 microns, and 500 microns for each trench. The emissivity from the concave trench design has maxima around vertical angles of-45 deg. and-30 deg. and horizontal angles of-45 deg., -30 deg., and 45 deg., for maximum depths of 50 and 500 microns. The emissivity from the concave trench design has a maximum around vertical-30 ° and around horizontal 0 ° for a maximum depth of 250 microns. The concave trench design does not have any significant emissivity location for all maximum depths. As such, varying the maximum depth for sloped and concave trench designs still fails to achieve the unexpected results obtained with convex trench designs.

Referring to fig. 1, a light guide plate having convex grooves may be used as a part of a light device in a light emitting method. First, light emitted from the light source 103 may be injected into the first edge 107 of the light guide plate 105. Then, the injected light may propagate within the light guide plate 105 by total internal reflection. Subsequently, the propagating light may pass through the first major surface 109 of the light guide plate 105 with a peak radiance oriented from about 0 ° to about 30 ° relative to a direction orthogonal to the first major surface 109 of the light guide plate 105. In another approach, the propagating light may pass through the first major surface 109 of the light guide plate 105 with a peak radiance oriented from about 0 ° to about 10 ° relative to a direction orthogonal to the first major surface 109 of the light guide plate 105.

While not wishing to be bound by theory, light may propagate within light guide plate 105 by total internal reflection at angles of incidence greater than a critical angle relative to the normal to the interface. FIG. 1 shows an example of a reflected ray 125 reflected with a light guide plate and exiting through a first major face. When light has an angle of incidence that is less than the critical angle of the interface, a portion of the light will be reflected while the remainder will be refracted through the material on the other side of the interface. While not wishing to be bound by existing theory, fresnel equations may be used to calculate the proportion of light that is reflected or refracted. Light may propagate within the material on the sides of the interface at different angles than light incident on the interface. Further, the refracted light may be incident on a second interface through which the refracted light may be further refracted. More specifically, some of the light within the light guide plate 105 may be refracted into the grooves 117. In general, it is assumed that such refracted light is lost. However, in some embodiments (e.g., embodiments having a grooved profile of the present disclosure), the refracted light passing through the first surface of the grooves may be able to re-enter the light guide plate 105 by refracting through the second surface of the grooves 117 through which the refracted light exits the light guide plate 105. A simplified example of a refracted ray 127 exiting through the channel 117 and re-entering the light guide plate 105 is shown in fig. 1. This light may further propagate within the light guide plate 105 by total internal reflection again before exiting through the first major face 109 of the light guide plate 105 after reflecting off another one of the plurality of grooves 117.

Fig. 14 depicts the percentage of light exiting the light guide plate into the convex grooves and directed back into the light guide plate as a function of the depth angle of the second convex portions of the second surface of the convex grooves according to embodiments described herein (e.g., with reference to fig. 1). The x-axis (horizontal axis) is the depth angle of the second convex portion 203 of the second surface 121 of the groove 117. The trench 117 also includes a first surface 119 that further includes a first convex portion 201. For fig. 14, the maximum depth of the trench 117 is 30 μm, and the depth angle of the first convex portion is 35 °. The y-axis (vertical axis) is the percentage of light that is directed back into the light guide plate. In fig. 14, the percentage of light guided back into the light guide plate 105 increases as the depth angle of the second convex portion 203 decreases. For a depth angle of about 55 ° of the second convex portion 203, at least 50% of the light is directed back into the light guide plate 105. For a depth angle of about 40 ° of the second convex portion 203, at least 55% of the light is directed back into the light guide plate 105. For a depth angle of about 20 ° of the second convex portion 203, at least 60% of the light is directed back into the light guide plate 105. In other embodiments where the second convex portion has a depth angle of less than 35 °, more light may be directed back into the light guide plate than shown in fig. 14.

Fig. 15 depicts the percentage of light that exits the light guide plate into the convex grooves and is directed back into the light guide plate as a function of the width of the grooves according to embodiments described herein. The x-axis (horizontal axis) is the width of the trench in millimeters. The y-axis (vertical axis) is the percentage of light that is directed back into the light guide plate. In fig. 15, a trench having a maximum depth of 30 microns includes a first surface further including a first convex portion having a depth angle of 35 °, a second surface further including a second convex portion having a depth angle of 35 °, and a base having a variable width. When the base is pointed, the trench width is 42 microns. For a groove width of 42 microns, about 60% of the refracted light is directed back into the light guide plate. For a groove width of about 80 microns, about 25% of the refracted light is directed back into the light guide plate. For a groove width of 100 microns, about 20% of the refracted light is directed back into the light guide plate.

The light guide plate according to embodiments described herein may be used as part of a light device in a method of emitting light. First, light emitted from the light source 103 may be injected into the first edge 107 of the light guide plate 105. Then, the injected light may propagate within the light guide plate 105 by total internal reflection. However, a portion of the light may exit the light guide plate 150 through the at least one groove 117, 301, 401, 501, 601, 701. However, a portion of the light exiting through the grooves 117, 301, 401, 501, 601, 701 may be directed back into the light guide plate 105. The percentage of light directed into the light guide plate 105 may affect the angular distribution of light exiting the first major face 109. In some embodiments, the light device 101 may not include a reflector 113. In such embodiments, refracted light exiting a first surface of a groove 117, 301, 401, 501, 601, 701 can only be recovered by re-entering the light-guide plate 105 through another surface of the corresponding groove 117, 301, 401, 501, 601, 701. Trenches having a maximum depth of less than about 50 microns, less than about 30 microns, less than about 20 microns, or between about 1 micron and about 50 microns, between about 5 microns and about 50 microns, between about 1 micron and about 30 microns, or between about 5 microns and about 30 microns may be preferred. In other embodiments, a depth angle of less than 50 °, less than 40 °, less than 30 °, less than 20 °, or less than 10 ° of the convex, sloped, or concave portion of the second surface of the groove may be preferred. In other embodiments, a width of less than 100 microns, less than 50 microns, less than 25 microns, or less than 10 microns of the base surface of the trench may be preferred. In some embodiments, the portion of light exiting the grooves 117, 301, 401, 501, 601, 701 and directed back into the light-guide plate 105 may be about 20% or more, about 30% or more, about 40% or more, about 50% or more, about 60% or more, or about 65% or more. In other embodiments, the portion of the light exiting the grooves 117, 301, 401, 501, 601, 701 and directed back into the light guide plate 105 may be between 20% and 90%, between 30% and 90%, between 40% and 90%, between 50% and 90%, between 20% and 75%, between 30% and 75%, between 40% and 75%, between 50% and 75%, between 30% and 65%, between 40% and 65%, or between 50% and 65%.

As used herein, the terms "the", "the" or "an" mean "at least one", and should not be limited to "only one", unless expressly indicated to the contrary. For example, reference to "an element" thus includes embodiments having two or more such elements, unless the context clearly dictates otherwise.

As used herein, the term "about" means that amounts, sizes, formulations, parameters, and other quantities and characteristics are or need not be exact, but may be approximate and/or greater or lesser reflection tolerances, conversion factors, rounding off, measurement errors, and the like, as desired, and other factors known to those of skill in the art. When the term "about" is used to describe a value or an end-point of a range, the disclosure should be understood to include the specific value or end-point referred to. If a value or range end point in this specification states "about," then that value or range end point is intended to include both embodiments: one is modified by "about" and one is not modified by "about". It will be further appreciated that the endpoints of each of the ranges are significant (significant) compared to the other endpoint and are significant independently of the other endpoint.

The terms "substantially", "essentially", and variations thereof as used herein are intended to describe the feature as being equal or nearly equal to a value or description. For example, a "substantially flat" surface is intended to indicate a flat or nearly flat surface. Also, as defined above, "substantially similar" is intended to indicate that the two values are equal or nearly equal. In some embodiments, "substantially similar" may indicate values within about 10% of each other, such as values within about 5% of each other, or values within about 2% of each other.

As used herein, the terms "comprises," "comprising," and variations thereof, are to be construed as synonymous and open-ended, unless otherwise indicated.

It should be understood that while the embodiments have been described in detail with respect to certain illustrative and specific examples thereof, the disclosure is not to be considered limited thereto, as many modifications and combinations of the disclosed features are possible without departing from the scope of the following claims.