Light guide plate design for asymmetric illumination

Abstract

An illumination assembly is provided that includes a plurality of light sources, a light guide plate, a back reflector, a front collector, and a plurality of microstructures. The light sources are configured to generate light and are disposed on a PCB. The light guide plate is disposed to receive the light generated by the light sources. The light guide plate and the plurality of light sources are separated by a gap. The back reflector is disposed along a first surface of the light guide plate. The front collector is disposed below a second surface of the light guide plate, opposite the first surface. The front collector is also disposed across the gap that separates the light guide plate and the plurality of light sources. The microstructures are disposed on the first surface of the light guide plate and are arranged in a pattern that provides asymmetric light distribution.

Description

Technical Field

[0001] The present disclosure generally relates to a light guide plate design for providing asymmetric illumination.

Background Art

[0002] Comfort is a key factor in implementing human-centric lighting in both indoor and outdoor applications. Applications that require asymmetric lighting, such as outdoor urban or road scenarios, currently rely on lens solutions. These lens solutions often use dot lenses or peanut lenses to achieve asymmetric light distribution, which leads to pixilation on the light emitting surface. Therefore, when directly viewing the light emitting surface of a lighting fixture, especially when viewed from the direction of the peak intensity, the emitted light is accompanied by significant glare, which is uncomfortable for the viewer. This discomfort can pose a significant safety hazard in outdoor applications such as road lighting.

[0003] Alternatively, some current solutions utilize light guide plates instead of lenses. These light guide plates typically utilize traditional techniques such as laser dots printed on the plate. These techniques result in high non-uniformity and limit their use in applications that require uniform light.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, there is a need in the art for an optical design, such as a light guide plate, that achieves side-lit asymmetric lighting with improved uniformity and reduced glare and pixilation, for example, in outdoor or urban lighting fixtures.

Means for Solving the Problems

[0005] The present disclosure relates to an illumination assembly that can generate asymmetric light with improved uniformity and reduced glare and pixilation compared to conventional optical designs. This illumination assembly may be used in outdoor and urban applications, such as for illuminating roads, sidewalks, and other outdoor infrastructure. Generally, the illumination assembly includes a plurality of light sources, such as light emitting diodes (LEDs), a printed circuit board (PCB), a light guide plate, a back reflector, and a front collector. The LEDs are disposed on the PCB. The light guide plate is disposed proximate to the LEDs to receive the light generated by the LEDs. The light guide plate is separated from the LEDs by a gap of air or another material having a refractive index different from that of the light guide plate. The light guide plate may be linear, circular, or any other suitable shape. If the light guide plate is circular, the PCB may be flexible (i.e., FPCB). The FPCB may be disposed around the circular light guide plate in a full or half perimeter configuration. The applicant recognizes and understands that a light guide plate design having the three-dimensional texture described herein can provide asymmetric illumination having an improved uniformity and a light window with reduced or no pixilation on its surface from any viewing angle.

[0006] As described herein, the back reflector is disposed above the upper surface of the light guide plate so as to cover the LED. In one example, the light generated by the LED travels through the light guide plate, is reflected by the back reflector, and exits the lighting assembly through the lower surface of the light guide plate. Thereafter, the LED light travels to a road or sidewalk located below the lighting assembly. The back reflector may be a mirror, semi-mirror, or non-mirror reflector. Further, the back reflector may be composed of one or more sub-components. In a further example, a side reflector is disposed on a third surface of the light guide plate, substantially perpendicular to the back reflector. The side reflector is disposed on the opposite side of the LED and the PCB so as to face the LED across the length of the light guide plate.

[0007] The front collector is configured to prevent light from escaping from the lighting assembly through a gap between the LED and the light guide plate. The front collector is positioned below the lower surface of the light guide plate so as to cover the LED. The front collector is used to reduce the spottiness and / or brightness from the LED.

[0008] To provide asymmetric light, the upper surface of the light guide plate is textured with a pattern of three-dimensional microstructures. In some examples, each of the microstructures may be symmetric, oval-like in shape. In some examples, one or more of the microstructures are filled with a material having a refractive index different from that of the light guide plate, and different microstructures may be filled with different materials having different refractive indices. In some examples, one or more of the microstructures are empty or vacant, i.e., without material. Further, one or more of the microstructures may have a rough surface, such as a roughness average (Ra) between about 0.1 and 20 micrometers. The microstructures may be arranged in various different patterns on the upper surface, such as circular, hexagonal, or any suitable alternative. The circular structure may include a plurality of concentric rings, and each ring may include a portion of a plurality of microstructures. Further, the dimensions and rotation angles of each microstructure may be a function of the position of the microstructure on the upper surface. For example, the microstructures closer to the center of the upper surface may be significantly larger than those positioned near the outer edge of the upper surface. Similarly, the microstructures near the edge of the upper surface may have a larger rotation angle than those positioned near the center of the upper surface. The pattern, placement, dimensions, and rotation angles of the microstructures are used to configure the directional angle of the light distribution provided by the light assembly.

[0009] Generally, in one aspect, a lighting assembly is provided. The lighting assembly includes a plurality of light sources. The plurality of light sources are configured to generate light. In one example, the plurality of light sources are disposed on a PCB.

[0010] The lighting assembly further includes a light guide plate. The light guide plate is arranged to receive light generated by a plurality of light sources. The light guide plate and the plurality of light sources are separated by a gap. According to one example, the light guide plate is substantially circular or non-circular. In this example, further, the plurality of light sources are arranged in a circular or non-circular arrangement around the light guide plate.

[0011] The lighting assembly further includes a back reflector. The back reflector is arranged along a first surface of the light guide plate. According to one example, the back reflector is a mirror reflector or a semi-mirror reflector.

[0012] The lighting assembly further includes a front collector. The front collector is arranged below a second surface of the light guide plate, which is opposite to the first surface. The front collector is also arranged across the gap separating the light guide plate and the plurality of light sources. According to one example, the front collector is configured to reflect light.

[0013] According to one example, the lighting assembly further includes a side reflector. The side reflector is arranged adjacent to a third surface of the back reflector and the light guide plate.

[0014] According to one example, the lighting assembly further includes a plurality of microstructures. The plurality of microstructures are arranged on the first surface of the light guide plate. In one example, each of the plurality of microstructures is defined by a rotationally or non-rotationally symmetric shape. Further, the rotationally or non-rotationally symmetric shape of the first microstructure of the plurality of microstructures may be scaled or stretched in at least one dimension with respect to the rotationally or non-rotationally symmetric shape of the second microstructure of the plurality of microstructures.

[0015] According to one example, one or more dimensions of one of the plurality of microstructures correspond to the position of the one microstructure of the plurality of microstructures on the first surface of the light guide plate. In another example, the rotation angle of one of the plurality of microstructures corresponds to the position of the one microstructure of the plurality of microstructures on the first surface of the light guide plate.

[0016] According to one example, the plurality of microstructures are arranged in a pattern including a plurality of concentric rings. The illumination assembly generates an asymmetric light distribution. The first microstructure of the first concentric ring of the plurality of concentric rings may be arranged at a different rotation angle from the second microstructure of the first concentric ring of the plurality of concentric rings.

[0017] According to one example, the plurality of microstructures are arranged in a hexagonal pattern. The illumination assembly may generate an asymmetric light distribution. The first microstructure of the hexagonal pattern may be arranged at a different rotation angle from the second microstructure of the hexagonal pattern.

[0018] It should be understood that all combinations of the above concepts and additional concepts discussed in more detail below (under the condition that such concepts do not conflict with each other) are contemplated as being part of the subject matter of the invention disclosed herein. In particular, all combinations of the claimed subject matter recited at the end of this disclosure are contemplated as being part of the subject matter of the invention disclosed herein. It should also be understood that the terms explicitly employed herein, which may also appear in any disclosure incorporated by reference, should be given the meaning that most closely matches the particular concepts disclosed herein.

[0019] These and other aspects of the various embodiments will become apparent and be elucidated with reference to the (multiple) embodiments described below.

Brief Description of the Drawings

[0020] In the drawings, like reference numerals generally refer to the same parts throughout different views. Also, the drawings are not necessarily to scale; instead, emphasis is generally placed on illustrating the principles of the various embodiments.

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Mode for Carrying Out the Invention

[0021] The present disclosure relates to an illumination assembly that can generate asymmetric light with improved uniformity and reduced glare and pixilation compared to conventional optical designs. This illumination assembly may be used in outdoor and urban applications such as for illuminating roads, sidewalks, and other outdoor infrastructure. Generally, the illumination assembly includes a plurality of light sources, such as light-emitting diodes (LEDs), a printed circuit board (PCB), a light guide plate, a back reflector, and a front collector. The LEDs are disposed on the PCB. The light guide plate is disposed adjacent to the LEDs so as to receive the light generated by the LEDs. The light guide plate is separated from the LEDs by a gap of air or another material having a refractive index different from that of the light guide plate. The light guide plate may be linear, circular, or any other suitable shape. The back reflector is disposed above the upper surface of the light guide plate so as to cover the LEDs. In a further example, side reflectors are disposed on the sides of the light guide plate. The side reflectors are disposed on the opposite side of the LEDs and the PCB so as to face the LEDs. The front collector is configured to prevent light from escaping from the illumination assembly through the gap between the LEDs and the light guide plate. The front collector is positioned below the lower surface of the light guide plate so as to cover the LEDs. To provide asymmetric light, the upper surface of the light guide plate is textured with a pattern of three-dimensional microstructures. In some examples, each of the microstructures may be symmetric, oval-like in shape. The microstructures may be arranged in various different patterns on the upper surface, such as radially or hexagonally.

[0022] FIG. 1 is a cross-sectional view of a non-limiting example of an illumination assembly 100. The illumination assembly 100 includes a plurality of LEDs 102, a light guide plate 106, a back reflector 110, a front reflector 114, a PCB 118, and a side reflector 120. As shown in FIG. 1, the LEDs 102 emit light that exits the light guide plate 106. The light is shown for illustrative purposes, and only two potential light paths 104a, 104b from the LEDs 102 to the light guide plate 106 are illustrated. One of ordinary skill in the art will understand that additional or alternative, more potential paths are possible. The LEDs 102 are mounted on the PCB 118. In some examples, the PCB 118 is a flexible PCB (FPCB) configured to conform to the shape (circular, linear, etc.) of the light guide plate 106.

[0023] The light guide plate 106 is disposed proximate to the plurality of LEDs 102 and configured to receive the light 104 generated by the LEDs 102. As shown in subsequent figures, the light guide plate 106 may be substantially circular, substantially semi-circular, substantially linear, or any other suitable shape. The light guide plate 106 may be defined by a first surface 112 that defines an upper portion of the light guide plate 106, a second surface 116 that defines a lower portion of the light guide plate 106, and a third surface 122 that defines a side portion of the light guide plate 106 opposite the LEDs 102 and the PCB 118. The space between the LEDs 102 and the light guide plate 106 is defined by a gap 108. As shown in subsequent figures, the light guide plate 106 includes a plurality of three-dimensional microstructures 124 on the first surface 112. The microstructures 124 are configured to convert the light 104a, 104b emitted by the LEDs 102 into an asymmetric light pattern 200 (see FIG. 2). Disposing the microstructures 124 on the first surface 112 breaks total internal reflection (TIR) or adjusts the TIR direction with respect to the second surface 116 to enable a downward light output.

[0024] The back reflector 110 is disposed along the first surface 112 of the light guide plate 106. The back reflector 110 is configured to reflect the light 104a, 104b emitted by the LED 102 substantially downward toward the second surface 116 of the light guide plate 106. The back reflector 110 may be a mirror, a semi-mirror, or a non-mirror surface. In some examples, the back reflector 110 may be a single component 110. In other examples, the back reflector 110 may be an assembly of two or more sub-components depending on the overall mechanical and / or electrical design constraints. In a preferred example, the back reflector 110 covers the first surface 112 of the light guide plate 106, the gap 108, and the top surface of the LED 102 so as to prevent the light 104 from escaping from the top of the lighting assembly 100. However, in other examples, the back reflector 110 may be separated from the PCB 118 by a second gap. This second gap may be required when the back reflector 110 is made of a metallic material. To prevent the light 104 from escaping through this second gap, an additional reflector, such as a white, non-metallic reflector, may be used to cover the gap. The example of FIG. 1 further includes a side reflector 120 configured to prevent the light 104 from escaping from the side of the lighting assembly 100 defined by the third surface 122 of the light guide plate 106. Thus, the side reflector 120 may be disposed adjacent to both the third surface 122 of the light guide plate 106 and the back reflector 110.

[0025] The front collector 114 is disposed below the second surface 116 on the side opposite to the first surface 112. Also, the front collector 114 is disposed across the gap 108 that separates the LED 102 and the light guide plate 106. In other words, the distance between the first and second ends of the front collector 114 is greater than the space within the gap 108. The front collector 114 prevents the light 104 from escaping from the illumination assembly 100 through the gap 108. Thus, the front collector 114 hides the spotty or over-brightness caused by the light 104 escaping through the gap 108.

[0026] The light 104a shows one possible path that the light can take within the illumination assembly 100. The light 104a is emitted by one of the LEDs 102 and directed downward. Thereafter, the front collector 114 reflects the light 104a upward. Thereafter, the back reflector 110 reflects the light 104a downward and exits the illumination assembly 100 through the second surface 116 of the light guide plate 106.

[0027] Similarly, the light 104b shows another possible path that the light can take within the illumination assembly 100. The light 104b is emitted by one of the LEDs 102 and directed perpendicular to the LED 102. Thereafter, the side reflector 120 reflects the light 104b downward and exits the illumination assembly 100 through the second surface 116 of the light guide plate 106. Following the reflection from the side reflector 120, the light 104b may be considered to proceed around the optical axis of one of the LEDs 102.

[0028] FIG. 2 is a further cross-sectional view of a non-limiting example of the illumination assembly 100. FIG. 2 shows the asymmetric light distribution 200 generated by the light assembly 100 as a result of the microstructure 124 disposed on the first surface 112 of the light guide plate 106.

[0029] FIG. 3A shows a light guide plate 106 with a single three-dimensional microstructure 124 disposed on a first surface 112 for illustrative purposes. The position 134 of the microstructure 124 is defined according to a light guide plate coordinate system 150. In this example, the position 134 of the microstructure 124 is the origin O of the light guide plate coordinate system 150.

[0030] FIGS. 3B and 3C define the dimensions of the microstructure 124 in the x, y, and z directions according to a texture coordinate system 175. In this example, the microstructure 124 has a width 126a of a in the x direction, a length 126b of b in the y direction, and a depth 126c of c in the z direction. In particular, FIGS. 3B and 3C show an example where a is greater than c but less than b. Other values of a, b, and c may be selected depending on the desired characteristics of the asymmetric light distribution 200 (see FIG. 2) provided by the illumination assembly 100.

[0031] In the example of FIG. 3A, the microstructure 124 is reflectively symmetrical with respect to its x, y, and z axes. In other examples, the microstructure 124 may be rotationally symmetrical with respect to a rotation angle. In further examples, the microstructure 124 may be overall asymmetric. In some examples, the microstructure 124 is filled with a material having a refractive index different from that of the light guide plate 106. In some examples, the microstructure 124 is not filled with a material having different refractive indices and is empty or vacant. Further, the microstructure 124 may have a rough surface, such as a roughness average (Ra) between about 0.1 and 20 micrometers.

[0032] FIG. 4A shows a light guide plate 106 having a single three-dimensional microstructure 124 with a position 134 offset from the origin O of the light guide plate coordinate system 150. The microstructure 124 may be defined by a rotation angle 128 with respect to the X-axis of the light guide plate coordinate system 150. FIGS. 4B and 4C define the dimensions 126a, 126b, 126c of the microstructure in the x-direction, y-direction, and z-direction, respectively, according to the texture coordinate system 175. In these examples, the dimensions 126a, 126b, 126c and the rotation angle 128 are determined as a function of the position 134 of the microstructure 124.

[0033] In the examples of FIGS. 4A-4C, the coordinates of the light guide plate coordinate system 150 may be represented as (Xg, Yg, Zg), and the coordinates of the texture coordinate system 175 may be represented as (Xt, Yt, Zt). As shown in FIGS. 4B and 4C, the microstructure 124 has a width 126a of a*A in the x-direction, a length 126b of b*B in the y-direction, and a depth 126c of c*C in the z-direction. In some examples, a, b, and c may be fixed values for a certain shape (such as an ovoid), while the coefficients A, B, and C may be a function of the position 134 of the individual microstructure 124. In one example, A may be determined according to the following equation: TIFF2025520808000002.tif894

[0034] In the example of Equation 1, A1, A g1 , A g2 , A g3 , and A g4 may be fixed values within a defined value range such as [-20, 20]. Similarly, B and C may be defined according to the following equations: TIFF2025520808000003.tif895TIFF2025520808000004.tif793

[0035] A1, A g1 , A g2 , A g3 , and A g4 Similarly, like B1, B g1, B g2 , B g3 , B g4 , C1, C g1 , C g2 , C g3 , and C g4 The variables of, and C may be fixed values within the defined value ranges, but the fixed values and value ranges will likely be different from the fixed value of A.

[0036] Furthermore, the rotation angle 128 may be defined according to the following formula: TIFF2025520808000005.tif694

[0037] Similar to the previous example, θ1, θ g1 , θ g2 , θ g3 , and θ g4 The variables of may be fixed values within a defined value range, such as [-90, 90].

[0038] FIG. 5 shows a top view of a circular light guide plate 106 having a plurality of microstructures 124 arranged in a substantially hexagonal pattern 132 to generate asymmetric light distribution 200. In some examples, the microstructures 124 of the substantially hexagonal pattern 132 may differ in terms of dimensions 126 and rotation angle 128 based on their position 134 on the light guide plate 106. For example, while each of the microstructures 124 shown in FIG. 5 is the same, one or more of the microstructures 124 can be different in terms of x, y, and z dimensions or rotation. In the example of FIG. 5, the fixed values A, B, C, and θ are A1 = 1, A g4 = 1.8, B1 = C1 = 1, C g1 = -5, and θ g2On the other hand, while one is 80, all other fixed values may be set to 0. Thus, the central column of the microstructure 124 is arranged at a rotation angle 128 of approximately 0 degrees. The microstructures 124 of the two columns adjacent to the central column are arranged at a rotation angle 128 slightly larger than 0 degrees. Therefore, the rotation angle 128 of the microstructure 124 is proportional to the distance of the position 134 of the microstructure 124 with respect to the central column. In FIG. 5, the semi - circle of the LED 102 is arranged around the outer edge of the light guide plate 106, while in FIG. 6, the full - circle of the LED 102 is arranged around the outer edge of the light guide plate 106.

[0039] FIG. 6 shows a top view of a further circular light guide plate 106 having a plurality of microstructures 124 arranged in a pattern including a plurality of concentric rings 130 to generate symmetric light distribution. For example, in FIG. 6, there are 6 microstructures 124 surrounding the central microstructure. These 6 microstructures 124 form one concentric ring. As shown in FIG. 6, 13 microstructures 124 surrounding the previous 6 microstructures form another concentric ring and continue outward in the same manner. In the exemplary pattern shown in FIG. 6, 4 concentric rings are formed around the central microstructure. In some examples, the microstructures 124 of each concentric ring 130 may differ in terms of dimension 126 and rotation angle 128 based on its position 134 on the light guide plate 106. As shown in FIG. 6, the microstructures 124 of each concentric ring 130 have approximately the same x, y, and z dimensions. However, within each concentric ring 130, each microstructure has a unique rotation angle 128. Further, the x, y, and z dimensions of the microstructures 124 of one concentric ring 130 are different from the x, y, and z dimensions of the microstructures of another concentric ring 130. Further, each concentric ring 130 includes a different number of microstructures 124. In the example of FIG. 6, the fixed values A, B, C, and θ are such that A1 = 1, A g3 = A g4 = 1.8, B1 = C1 = 1, C g1 = - 5, and θ g1 = 30, while all other fixed values may be set to 0. The full - circle of the LED 102 is arranged around the outer edge of the light guide plate 106.

[0040] FIG. 7 shows a cross-sectional view of a light guide plate 106 having a plurality of microstructures 124 disposed on a first surface 112 of the light guide plate 106. As shown in FIG. 7, each column of the microstructures 124 has a unique depth 126c. For example, the microstructures 124 shown at the top of FIG. 7 have the greatest depth, the microstructures at the bottom of FIG. 7 have the least depth, and each microstructure therebetween has a depth between the greatest depth and the least depth.

[0041] FIG. 8A is a top view of the lighting assembly 100, while FIG. 8B is a bottom view of the same lighting assembly 100. FIG. 8A shows a circular upper frame assembly 136. In other examples, the upper frame assembly 136 may be non-circular in shape, such as rectangular or linear. The upper frame assembly 136 may include mounting holes for attaching the lighting assembly 100 to a lamppost, light pole, or other outdoor lighting structure via screws, bolts, or other suitable means. FIG. 8B shows a lower frame assembly 138. As illustrated in FIG. 9, the lower frame assembly 138 is mechanically coupled to the upper frame assembly 136 so as to surround other components of the lighting assembly 100. Further, the lower frame assembly 138 is hollow and exposes a second (lower) surface 116 of the light guide plate 106.

[0042] FIG. 9 shows an exploded view of a non-limiting example of the lighting assembly 100. As shown in FIG. 9, the lighting assembly 100 includes an upper frame assembly 136, a back reflector 110, a plurality of LEDs 102 disposed on a flexible, semi-circular strip of PCB 118, a light guide plate 106 having a plurality of microstructures 124, an O-ring 140, a front collector 114, and a lower frame assembly 138. The O-ring 140 is used to protect the components of the lighting assembly 100 disposed within the upper frame assembly 136 and the lower frame assembly 138 from environmental conditions.

[0043] FIG. 10 shows an exemplary spatial light distribution of a light assembly contemplated herein. Optically, the illustrated spatial light distribution is defined by the C-plane 142 and the gamma angle G. The normal N is oriented perpendicular to the light emitting surface 116 of the light guide plate 106. The normal N can also be a virtual line passing through the center of the luminaire. Any angle with respect to the normal N is defined as the gamma angle G. The C-plane 142 passes through the normal N and is disposed with respect to the second (lower) light emitting surface 116 of the light guide plate 106. In other words, the C-plane 142 is disposed along the longitudinal direction of the application or luminaire. Any angle with respect to the C-plane 142 is defined by the C-plane angle C, and the C-plane angle C is referenced as the amount of rotation about the normal N. The asymmetric light distribution 200 (see FIG. 2) generated by the lighting assembly 100 is defined by the C-plane angle C and the gamma angle G. The intensity I of the asymmetric light distribution 200 can be defined as a function of the C-plane angle C and the gamma angle G, for example, I(C, Gamma).

[0044] FIG. 11 shows enlarged portions 144a, 144b, 144c of a plurality of microstructures 124a, 124b, 124c of the light guide plate 106. In particular, the enlarged portions show how the microstructure 124 changes in terms of both the dimension 126 and the rotation angle 128. In this way, the light guide plate 106 of FIG. 11 may be considered a real-world version of the light guide plate shown in FIG. 5. The dimension 126 and the rotation angle 128 of each microstructure 124 are based on the position 134 of each microstructure 124 and a number of predefined coefficients (A1, A g1It is defined based on the formulas (1) to (4) discussed in this specification that determine the dimension 126 and the rotation angle 128 based on (etc.). In the first portion 144a, the microstructure 124a is arranged at an angle of approximately -65 degrees with respect to the normal N (see FIG. 10). In the second portion 144b, the microstructure 124b is arranged substantially parallel to the normal N. In the third portion 144c, the microstructure 124c is arranged at an angle of approximately 65 degrees with respect to the normal N. In this example, the coefficients used to form each microstructure 124 are designed to achieve an asymmetric light distribution 200 (see FIG. 2) for road lighting. Road lighting requires that the lighting assembly 100 illuminate at a peak intensity with a spacing defined by 6 times the mounting height of the lighting assembly 100, a forward illumination field defined by 1.5 times the mounting height, and a C-plane angle C of 65 degrees. Referring to the microstructures 124 in FIGS. 4A - 4C and Formulas 1 - 4, when b is greater than a, θ g2 is approximately 65 degrees. Thus, the microstructures 124a, 124c are oriented in the direction of the peak intensity.

[0045] FIG. 12 is a light distribution graph of the exemplary light guide plate 106 of FIG. 11. In FIG. 12, B indicates the blue region, G indicates the green region, R1 and R2 indicate the red regions, and P1, P2, and P3 indicate the purple regions. Further in this example, FIG. 13 is an illuminance plot corresponding to the exemplary light guide plate 106 of FIG. 11. The illuminance plot shows that the exemplary light guide plate 106 generates a bat-wing-shaped asymmetric light distribution 200 on the road. In this example, the lighting assembly 100 is 6 m high, is spaced 36 m from other lights, and is mounted with a forward distance of 7.6 m. As a result of this arrangement, the ratio of the average illuminance (E min ) to the minimum illuminance (E ave ) is 2.33, and the ratio of the maximum illuminance (E min ) to E max is 4.22. E ave:E min The ratio is 4.5, and E max :E min Compared with a traditional light guide plate solution where the ratio is 11, the light guide plate 106 of FIG. 11 represents a significant improvement compared to existing light guide plates used in road lighting applications.

[0046] FIG. 14 shows a modified example of the light guide plate 106 where the light guide plate 106 is non-circular instead of circular. In FIG. 14, a plurality of microstructures 124 are arranged in a semi-hexagonal pattern 132.

[0047] All definitions, as defined and used herein, are to be understood to govern the dictionary definition, the definition in the documents incorporated by reference, and / or the ordinary meaning of the defined terms.

[0048] The indefinite articles "a" and "an", as used in this specification and the claims, should be understood to mean "at least one" unless clearly indicated otherwise.

[0049] The phrase "and / or", as used in this specification and the claims, should be understood to mean "either or both" of the elements so combined, i.e., elements that are present conjunctively in some cases and disjunctively in other cases. A plurality of elements listed with "and / or" should be construed in the same manner, i.e., as "one or more" of the elements so combined. Other elements other than those specifically identified by the "and / or" clause may optionally exist whether or not they are related to those specifically identified elements.

[0050] As used in this specification and the claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when separating items in a list, "or" or "and / or" is to be construed as inclusive, i.e., including at least one, but also including, optionally, additional items not enumerated among several elements or among a list of elements, two or more of which are listed. Only terms such as "only one of", "exactly one of", or "consisting of" when used in the claims, where the contrary is clearly indicated, refer to including exactly one of several elements or a list of elements. In general, the term "or" when used in this specification is to be construed as indicating an exclusive alternative (i.e., "one or the other, but not both") only when preceding an exclusive term such as "any of", "one of", "only one of", or "exactly one of".

[0051] As used in this specification and the claims, the phrase "at least one" referring to a list of one or more elements means at least one selected from any one or more of the elements in the list of those elements, but not necessarily including at least one of each of the specifically enumerated elements in the list of those elements, and it should be understood that it does not exclude any combination of the elements in the list of those elements. This definition also allows for the possibility that elements other than those specifically identified in the list of elements referred to by the phrase "at least one" may optionally exist, whether or not they are related to those specifically identified elements.

[0052] Also, unless clearly indicated otherwise, in any method claimed in this specification that includes two or more steps or acts, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are listed.

[0053] In the claims and the above specification, it should be understood that all transitional phrases such as "comprising", "including", "carrying", "having", "containing", "accompanying", "holding", "consisting of", etc. are open-ended, that is, they are meant to include but not be limited to. Only the transitional phrases "consisting of" and "consisting essentially of" are to be closed or semi-closed transitional phrases, respectively.

[0054] Other implementations are within the scope of the following claims and other claims that the applicant may have rights to.

[0055] Although various examples have been described and illustrated in this specification, those skilled in the art will readily conceive of various other means and / or structures for performing the functions described in this specification and / or for obtaining one or more of the results and / or advantages thereof, and each such variation and / or modification is considered to be within the scope of the examples described in this specification. More generally, all parameters, dimensions, materials, and configurations described in this specification are intended to be exemplary, and those skilled in the art will readily understand that the actual parameters, dimensions, materials, and / or configurations will depend on the particular application in which the teachings of the present invention are used. Those skilled in the art will be able to recognize, or confirm, many equivalents to the specific examples described in this specification using only routine experimentation. Therefore, it should be understood that the above examples are presented only by way of example, and that examples other than those specifically described and claimed may be practiced within the scope of the appended claims and their equivalents. The examples of the present disclosure are directed to each individual feature, system, article, material, kit, and / or method described in this specification. Furthermore, any combination of two or more such features, systems, articles, materials, kits, and / or methods is included within the scope of the present disclosure if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent.

Claims

1. Multiple light sources configured to generate light, A light guide plate is positioned to receive light generated by the plurality of light sources, wherein the light guide plate and the plurality of light sources are separated by a gap, A back reflector positioned along the first surface of the light guide plate, A front collector is positioned below the second surface of the light guide plate, opposite to the first surface, and across the gap separating the light guide plate and the plurality of light sources. A plurality of microstructures arranged on the first surface of the light guide plate, wherein the plurality of microstructures are arranged in a predetermined pattern, and at least two or more microstructures differ in terms of dimensions and / or rotation angle based on their position on the light guide plate, A lighting assembly including, This lighting assembly generates asymmetric light distribution.

2. The lighting assembly according to claim 1, wherein the plurality of light sources are arranged on a printed circuit board.

3. The lighting assembly according to claim 1, further comprising a side reflector positioned adjacent to the back reflector and the third surface of the light guide plate.

4. The lighting assembly according to claim 1, wherein the back reflector is a mirrored reflector or a semi-mirrored reflector.

5. The lighting assembly according to claim 1, wherein the front collector is configured to reflect the light.

6. The lighting assembly according to claim 1, wherein the light guide plate is substantially circular or non-circular.

7. The lighting assembly according to claim 1, wherein the plurality of light sources are arranged in a circular or non-circular arrangement around the light guide plate.

8. The lighting assembly according to claim 1, wherein each of the plurality of microstructures is defined by a rotational or rotationally symmetric shape, and the rotational or rotationally symmetric shape of a first microstructure of the plurality of microstructures is scaled or stretched by at least one dimension with respect to the rotational or rotationally symmetric shape of a second microstructure of the plurality of microstructures.

9. The lighting assembly according to claim 1, wherein the dimensions of one or more of the microstructures of the plurality of microstructures correspond to the position of one of the microstructures of the plurality of microstructures on the first surface of the light guide plate.

10. The lighting assembly according to claim 1, wherein the rotation angle of one of the plurality of microstructures corresponds to the position of one of the plurality of microstructures on the first surface of the light guide plate.

11. The lighting assembly according to claim 1, wherein the plurality of microstructures are arranged in a pattern including a plurality of concentric rings.

12. The lighting assembly according to claim 11, wherein the first microstructure of the first concentric ring of the plurality of concentric rings is arranged at a different rotation angle than the second microstructure of the first concentric ring of the plurality of concentric rings.

13. The lighting assembly according to claim 1, wherein the plurality of microstructures are arranged in a hexagonal pattern.

14. The lighting assembly according to claim 13, wherein the first microstructure of the hexagonal pattern is arranged at a different rotation angle than the second microstructure of the hexagonal pattern.

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