Lighting system including diffusion control

Abstract

The invention relates to a lighting system including diffusion control. A lighting assembly comprising: a light guide; and a plurality of light sources configured to emit light into an edge of the light guide, where the light guide includes a plurality of air gaps arranged such that each air gap of the plurality of air gaps (i) is parallel to another air gap, (ii) is between adjacent light sources of the plurality of light sources, and (iii) extend in a direction in which light from the plurality of light sources propagates in the light guide.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 627,371, filed on January 31, 2024, which is hereby incorporated by reference herein for all purposes as if fully set forth herein. Background of the Disclosure

[0003] The present disclosure relates to lighting systems including light guides. More specifically, the present disclosure relates to lighting systems including light guides having light diffusion control features.

[0004] Illumination modules or lighting units are used to increase light in the case of generating visible images. Backlight modules or backlight units can be used to illuminate liquid crystal displays (LCDs) since LCDs do not generate light. The backlight unit illuminates the LCD from the back of the display panel. For a reflective LCD, a front - light unit can illuminate the LCD from the front of the display panel so that the LCD is readable under low ambient lighting conditions. The lighting unit can also be used for decorative applications, decals, or signs.

[0005] Conventional lighting units can include a light source, a light guide, and a light control structure. The light source can be of any different type, i.e., fluorescent lamp, incandescent lamp, light - emitting diode (LED), etc. The light guide can be a substantially planar optical structure or film for guiding or transmitting the light captured from the light source to the location where light is needed. In direct illumination, the light source irradiates the light guide on a main surface. In edge illumination, the light source irradiates the light guide along an edge. The light control features can be provided by an optical structure to manipulate the light emitted from the light source. For example, the light control structure can include a diffuser that scatters light and increases illumination uniformity, a color filter that changes the color of the light, a reflector that preserves light, a polarizer that changes the light properties, etc.

[0006] When a light - guiding film is illuminated by multiple LEDs at the edge, the light from each individual LED spreads throughout the light - guiding film as it propagates through the film. Uniform illumination from multiple light emitters is generally desired. However, when creating a moving - light effect, for example, when individually controlling the color / brightness of each LED used, a moving - light effect can be created, and excessive diffusion results in a blurred pattern. In such a case, it is desirable to control the amount of light diffusion that occurs in the light - guiding film (especially the diffusion that occurs in the non - visible region of the lighting unit (since LEDs are typically outside this part of the visible region)).

[0007] In order to maximize lighting efficiency, minimize power, dissipate heat, and achieve the desired lighting results in a lighting unit, it is necessary to manage and control the light in the lighting unit for a specific application. Summary of the Invention

[0008] The disclosed embodiments provide features and methods for minimizing light diffusion in lighting units that use point light sources (such as LEDs). Such results are desirable in dynamic lighting applications. Some materials are not easily illuminated from behind, and the disclosed features allow for the creation of complex illustrations and graphics directly on the surface of materials such as wood, carbon fiber, stone, aluminum, etc.

[0009] Optical waveguides that include light diffusion control provide images with higher resolution, brightness, contrast, and quality. In some embodiments, the optical waveguide may include air gaps to create illumination channels in non-visible regions. In some embodiments, the optical waveguide may include absorption lines to create illumination channels in visible regions. In some embodiments, the optical waveguide may include both air gaps and absorption lines.

[0010] In some applications, it is desirable to control the amount of diffusion that occurs, particularly in non-visible regions of the structure. Films with light dispersion control allow for minimal light dispersion, resulting in images with better resolution and quality, higher brightness, and high contrast. Some materials are not easily illuminated from behind, and this technology allows for the creation of complex icons and graphics directly on the surface of the material.

[0011] In one embodiment, a lighting assembly includes an optical waveguide; and a plurality of light sources configured to emit light into an edge of the optical waveguide, wherein the optical waveguide includes a plurality of air gaps arranged such that each air gap of the plurality of air gaps (i) is parallel to another air gap, (ii) is between adjacent light sources of the plurality of light sources, and (iii) extends in a direction in which light from the plurality of light sources propagates in the optical waveguide.

[0012] In one aspect, the optical waveguide includes a diffusion region on a side closest to the plurality of light sources and a uniform region that passes through the diffusion region, and the plurality of air gaps are located in and / or disposed in the diffusion region.

[0013] In one aspect, the diffusion region is hidden from a viewer, and light emitted from the plurality of light sources mixes in the uniform region and is visible to the viewer.

[0014] In one aspect, the optical waveguide is flexible such that the diffusion region wraps around and is located behind a background.

[0015] In one aspect, each air gap of the plurality of air gaps is configured to substantially eliminate light that propagates through the air gap.

[0016] In one aspect, each air gap of the plurality of air gaps is filled with a light-absorbing material.

[0017] In one aspect, at least some of the plurality of air gaps are filled with a light-absorbing material.

[0018] In one aspect, the surfaces of the light guide that are located at or adjacent to the plurality of air gaps are covered with a light-absorbing material.

[0019] In one aspect, the surfaces of the light guide that are located at or adjacent to the plurality of air gaps are covered with a light-reflecting material.

[0020] In one aspect, each of the plurality of light sources is a light-emitting diode.

[0021] In one aspect, the plurality of light sources includes a plurality of light-emitting diodes.

[0022] In one aspect, the light guide includes a protective layer disposed on at least one major surface.

[0023] In one aspect, the light guide includes a plurality of parallel light-absorbing lines, each of the plurality of light-absorbing lines being aligned with at least one of the plurality of air gaps.

[0024] In one aspect, the plurality of light-absorbing lines are located on or within one major surface of the light guide.

[0025] In one aspect, the plurality of light-absorbing lines are located on or within two major surfaces of the light guide.

[0026] In one aspect, the decoration is front-illuminated by the lighting assembly.

[0027] In another embodiment, a display system includes a reflective display; a background located behind the reflective display; and a lighting assembly configured to front-illuminate the reflective display, wherein the lighting assembly includes a light guide, a plurality of light sources configured to emit light into an edge of the light guide, and a plurality of air gaps arranged in a planar light guide such that each of the plurality of air gaps (i) is parallel to another air gap, (ii) is between adjacent light sources of the plurality of light sources, and (iii) extends in a direction in which light from the plurality of light sources propagates in the light guide.

[0028] In one aspect, a diffusion region is located within the housing.

[0029] The above and other features, elements, characteristics, steps, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1A and Figure 1B shows an application of the lighting unit.

[0031] Figure 2A and Figure 2B shows the configuration of the front lighting unit.

[0032] Figure 3 shows the edge lighting unit.

[0033] Figure 4 shows the configuration of the light guide according to an exemplary embodiment.

[0034] Figure 5 is a representation of a side view of the light guide.

[0035] Figures 6 to 9 is a representative side view of the light guide for lighting decoration.

[0036] Figure 10 shows the configuration of the lighting unit according to an exemplary embodiment.

[0037] Figures 11 to 16 is the result of ray tracing simulation in a light guide without an air gap.

[0038] Figures 17 to 24 is the result of ray tracing simulation in a light guide with an air gap.

[0039] Figure 25 is a front plan view of a part of the lighting unit according to an exemplary embodiment. Detailed Description

[0040] Now, embodiments of the present disclosure will be described in detail, examples of which are shown in the accompanying drawings. Whenever possible, the same reference numerals will be used in all the drawings to represent the same or similar components. However, the present disclosure may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein.

[0041] Herein, a range may be expressed as from “about” a particular value and / or to “about” another particular value. When expressing such a range, another embodiment includes from a specific value and / or to another specific value. Similarly, when a value is expressed as an approximation by using the antecedent “about”, it should be understood that the specific value forms another embodiment. It should also be understood that each endpoint of each range is meaningful relative to the other endpoint and independent of the other endpoint.

[0042] Directional terms used herein, such as up, down, right, left, front, back, top, bottom, vertical, horizontal, are only with reference to the accompanying drawings and are not intended to imply absolute directions.

[0043] Unless otherwise expressly stated, no method described herein is intended to be construed as requiring that its steps be performed in a particular order, nor as requiring the use of any apparatus to be specifically oriented. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or where any apparatus claim does not actually recite an order or orientation of individual components, or where the steps are not otherwise specifically recited in the claims or the specification as being limited to a particular order, or where no specific order or orientation of components of an apparatus is recited, no inference of order or orientation is intended in any respect. This applies to any possible basis of non-explicit interpretation, including logical issues regarding the arrangement of steps, operational flow, order of components, or orientation of components; simple meanings derived from grammatical organization or punctuation; and the number or type of embodiments described in the specification.

[0044] As used herein, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, references to a component include aspects having two or more such components unless the context clearly indicates otherwise.

[0045] In the following description, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration specific exemplary embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the concepts disclosed herein, and it is to be understood that various disclosed embodiments may be modified and other embodiments may be utilized without departing from the scope of the disclosure. Accordingly, the following detailed description should not be construed as limiting.

[0046] Figure 1A and 1B An example of an application of the lighting unit is shown. For example, the lighting unit can be used to present electronically generated information and / or decorative graphics in a frontlighting application for a reflective display. As shown, the application can be used to display icons, graphics, and logos on a reflective display in front of difficult-to-illuminate materials such as wood, leather, carbon fiber, stone, metal, textiles, and the like. The application shown in FIG. 1 can include a reflective display or decoration 10, a background 12, and electronics 14 for a housing (not shown). The electronics 14 can include a power source, a light source, control electronics for driving the display and the light source, and an enclosure.

[0047] The lighting unit allows complex icons and graphics of a reflective display to be viewed directly in front of the background surface. Figure 2A and 2B An example of a configuration of a lighting unit that can be used, for example, to frontlight the reflective display shown in FIG. 1 is shown. Figure 2A is a perspective view of a portion of the lighting unit 20.Figure 2B Front plan view of a portion of the lighting unit 20, which may have an edge lighting configuration where a plurality of LEDs 22 mounted to a circuit board 24 are used to emit light into the edge of a light guide 26. The LEDs 22 may be white, one color, multiple colors, or include a number of LEDs emitting different colors.

[0048] Figure 2A And 2B The straight line across the light guide 26 in [Figure] represents a virtual demarcation of two lighting regions in the light guide 26. The region on the side of the line closest to the LEDs 22 may be a diffusing region 261 where light emitted from different LEDs 22 diffuses and mixes together to define a uniform or homogeneous region 262, which may be the region on the other side of the line.

[0049] LEDs are actually point sources that require space to diffuse to define a uniform pattern, especially when using light from multiple LEDs. This characteristic is illustrated in [Figure], which depicts light emitted from each LED 22 in a conical pattern. The light emitted closer to the LEDs 22 may not be as uniform as the light that has mixed from multiple LEDs 22 and is farther from the LEDs 22. The illumination in the diffusing region 261 of the light guide 26 may be non-uniform or not pleasant enough for visual or display applications. Therefore, the diffusing region 261 of the light guide 26 can be hidden or out of the viewer's line of sight. For example, in the application shown in Figure 1, the diffusing region can be located inside the housing such that the non-uniform light emitted from the LEDs is not visible. In other applications, the light guide can be flexible such that the diffusing region can wrap around a background and be located behind the background. Figure 3 Figure [Figure number] shows an example of the geometric configuration of a light guide 40 according to one embodiment. As shown, the light guide 40 may include a substantially planar light guide and decoupling structure 42 at the center, which may be bonded to a protective layer 46 on the top and bottom using an optical adhesive 44. The light guide and decoupling structure 42 may be a sheet or film of an optical material such as polycarbonate, acrylic, glass, or any other suitable material. The protective layer 46 may also be a sheet or film of an optical material (e.g., polycarbonate, acrylic, glass, or any other suitable material). The adhesive 44 may be any suitable optical grade adhesive, including silicone, epoxy resin, etc. In some embodiments, the adhesive 44 may be a liquid, gel, or sheet and may be curable by UV, moisture, temperature, or self-curing. In some embodiments, the adhesive 44 may be a pressure sensitive adhesive (PSA). The adhesive 44 must have a refractive index lower than that of the light guide and decoupling structure 42 in order for total internal reflection to occur within the light guide 40.

[0050] Figure 4 Figure [Figure number] shows an example of the geometric configuration of a light guide 40 according to one embodiment. As shown, the light guide 40 may include a substantially planar light guide and decoupling structure 42 at the center, which may be bonded to a protective layer 46 on the top and bottom using an optical adhesive 44. The light guide and decoupling structure 42 may be a sheet or film of an optical material such as polycarbonate, acrylic, glass, or any other suitable material. The protective layer 46 may also be a sheet or film of an optical material (e.g., polycarbonate, acrylic, glass, or any other suitable material). The adhesive 44 may be any suitable optical grade adhesive, including silicone, epoxy resin, etc. In some embodiments, the adhesive 44 may be a liquid, gel, or sheet and may be curable by UV, moisture, temperature, or self-curing. In some embodiments, the adhesive 44 may be a pressure sensitive adhesive (PSA). The adhesive 44 must have a refractive index lower than that of the light guide and decoupling structure 42 in order for total internal reflection to occur within the light guide 40.

[0051] Figure 5 This is an example of a representation of a side view of the light guide 50, which shows the light rays emitted by the LED 22 and propagating in the light guide 50. The light guide 50 may include a light guide layer 52 protected by transparent protective layers 56 on the top and bottom surfaces, and the transparent protective layers 56 are bonded to the light guide layer 52 using PSA 54. As shown, the light rays can be emitted by the LED 22 into the light guide layer 52. The light rays can generally propagate through the light guide layer 52 in three dimensions via total internal reflection until the incident angle of the light rays increases to the critical angle and the light rays leave the light guide layer 52. Reflectors (not shown), management of the refractive indices of the respective layers, and other means can be used to control the direction of the light output from the light guide 50.

[0052] In an exemplary embodiment, the light guide layer 52 can be 50 μm thick, the PSA 54 layers can each be 40 μm thick, and the protective layer 56 can be 100 μm thick. The PSA 54 layer can be a silicone-based adhesive, and the protective layer 56 can be polycarbonate. In another exemplary embodiment, the thickness of the light guide layer 52 can be 50 μm, the thicknesses of the PSA 54 layers can both be 40 μm, and the thickness of the protective layer 56 can be 50 μm. In another exemplary embodiment, the thickness of the light guide layer 52 can be 50 μm, the thicknesses of the PSA 54 layers can both be 40 μm, the thickness of one protective layer 56 can be 100 μm, and the thickness of the other protective layer 56 can be 50 μm. However, those of ordinary skill in the art will understand that these thicknesses are merely illustrative, and these layers can have other suitable thicknesses.

[0053] Figures 6 to 9 Shows several configurations of the light guide orientation with respect to a reflective display or graphic decoration. Figures 6 to 9 Is a representative side view of a light guide that can illuminate a decoration with arrows indicating the direction of light. Figure 6 Shows that Figure 4 The light guide 60 constructed similarly to the light guide 40 shown can emit light in one direction from one main surface to illuminate the decoration 61. Figure 7 Shows that Figure 4 The light guide 70 constructed similarly to the light guide 40 shown in Figure 8 Shows that Figure 4 The light guide 80 constructed similarly to the light guide 40 shown can emit light in one direction from the main surface to illuminate the decoration 81 after removing the bottom protective layer. Figure 9 Shows that Figure 4 The light guide 90 constructed similarly to the light guide 40 shown can emit light in the opposite direction from the opposite main surface to illuminate the decoration 91 after removing the top protective layer.

[0054] In some embodiments, it is desirable to maintain the separation of the illumination regions to produce a particular illumination pattern or effect. For example, light diffusion control features can be included in the light guide to provide an illumination pattern that is narrower than the Figure 3 illumination pattern shown. Figure 3 It is shown that the light emitted from the LED 22 can start to diffuse as soon as it enters the light guide 26. Figure 10 The configuration of an illumination unit device that limits light diffusion according to an exemplary embodiment is shown.

[0055] Similar to the Figure 3 configuration, Figure 10 it is shown that the LED 22 emits light into the edge of the light guide 100. However, the portion of the light guide 100 between the positions of adjacent LEDs has been cut or removed to create an air gap 102. The air gap 102 can be long and narrow and extend in a direction perpendicular to the edge of the light guide 100 where the LEDs emit light. The air gap 102 can be defined by the air interface of the light guide / substantially eliminating the propagation of light through the air gap 102 for the light emitted by the LED 22. As a result, the air gap 102 can eliminate the light diffusion from the LED 22 until the light travels through the channel and passes the end of the air gap 102. The air gap 102 can be located within an area that is not visible to the viewer, i.e., within the channel area 101. In some embodiments, the air gap 102 can be filled with a light absorbing material to ensure that the light from one LED 22 does not pass through the air gap 102 and enter the light channel created for the adjacent LED 22. In some embodiments, the surface of the light guide material at the air gap 102 can be covered with a light absorbing material. In some embodiments, the surface of the light guide material at the air gap 102 can be covered with a light reflecting material.

[0056] Figures 11 to 25 is an example of the graphical result of a ray tracing simulation that compares the light ray paths in a light guide without an air gap as shown in Figure 3 with the light ray paths in a light guide with an air gap as shown in Figure 10 shown. Figures 11 to 16 produced by the ray tracing simulation in a light guide without an air gap as shown in Figure 3 shown. Figures 17 to 25 produced by the ray tracing simulation in a light guide with an air gap as shown in Figure 10 shown.

[0057] Figure 11Shows an example of a plan view of a gapless analog structure, which includes 10 white light LEDs 1122 (one at each blue vertical line), which are spaced at regular intervals on the X (red) scale and emit light into the edge of a rectangular light guide 1126 in the direction of the Y (green) scale. The light guide 1126 may include a diffusion region 11261 and a uniform region 11262. As shown, the uniform region 11262 may include a dot pattern on the surface of the light guide 1126 for extracting light. Figure 12 is Figure 11 An example of a closer view of the same gapless analog structure shown.

[0058] Figures 13 to 16 Shows an example of the simulation results of the gapless analog structure. In Figure 13 it, the light rays within the light guide 1126 are depicted by dashed lines. The light rays that have left the light guide 1126 are represented by solid lines. As Figure 13 shown, the light rays emitted from the LED 1122 that have entered the light guide 1126 may be randomly distributed within the diffusion region 11261.

[0059] Figure 14 Is a different view of the simulation results, where different colors represent the relative light output. Although Figure 14 it shows that some light has escaped along the edge, no light can be emitted from the diffusion region 11261, and most of the light can be output from the uniform region 11262. Figure 15 Is a different view of the simulation results, which may also include a color logarithmic scale of the relative light output.

[0060] Figure 16 Is similar to Figure 15 the view, but shows the light output contribution of each LED 1122. In the simulation, the LEDs 1122 are numbered from 1 to 10 from left to right on the edge of the light guide 1126. Figure 16 The top row in it represents the light output from LEDs 1 to 5 from left to right, and the bottom row represents the light output from LEDs 5 to 10 from left to right. As shown, for each LED 1122, there are some inconsistencies in the lower part of the uniform region, where the overall light output is consistent among LEDs 1 to 10.

[0061] Figure 17An example of a plan view showing a gap simulation structure is presented, which includes 10 white light LEDs 1722 (one at each blue vertical line), which are spaced at regular intervals across the X (red) scale and emit light into the edge of a rectangular light guide 1126 in the direction of the Y (green) scale. The light guide 1726 may include a diffusion region 17261 and a uniform region 17262. As shown, the diffusion region 17261 may include a plurality of air gaps 17263, which may extend in a straight line from the edge of the light guide 1726 irradiated by the LED 1722 through the diffusion region 17261 to the uniform region 17262. As shown, the uniform region 17262 may include a dot pattern on the surface of the light guide 1726 for extracting light. Figure 18 is Figure 17 an example of a closer view of the same gap simulation structure shown.

[0062] Figures 19 to 25 is an example showing the simulation results of the gap simulation structure. In Figure 19 it, the light rays within the light guide 1726 are depicted by dashed lines. The light rays that have left the light guide 1726 are depicted by solid lines. In Figure 19 it, among the ten LEDs 1722, LED one, four, seven, and ten have been turned on. As Figure 19 shown, the light rays emitted from the turned-on LEDs 1722 that have entered the light guide 1726 can stay within the channels defined between the air gaps 17263 by total internal reflection before becoming randomly distributed after entering the uniform region 17262. Figure 20 is a perspective view of an example of the simulation results when LEDs one, four, six, seven, nine, and ten are turned on. In [[ID=1}} Figure 20 it, the Z scale is blue. Figure 21 is a view of the surface of the light guide 1726, which has a simulation configuration similar to that shown in Figure 20 it, but without any diffusion control features. Figure 21 is used to compare Figure 20 the benefits of the diffusion control features shown with the same lighting setup without diffusion control features.

[0063] Figure 22 is an example of a different view of the simulation results, where different colors represent relative light output. Figure 22 shows that some light can escape within the channels in a part of the diffusion region 17261 near the uniform region 17262. Although the simulation shows that some light can be emitted from the diffusion region 17261, most (e.g., the majority) of the light can be output from the uniform region 17262. Figure 23 [[ID= :]]is a different view of the gap simulation results, which also includes a color logarithmic scale of relative light output.

[0064] Figure 24 is similar to Figure 23 , but shows the light output contribution of each LED 1722. Figure 24 The top row in represents the light output from LEDs 1 through 5, with LED 1 being the far left and LED 5 being the far right. Figure 24 The bottom row of LEDs 6 to 10, where LED 6 is the leftmost (ie, below LED 1) and LED 10 is the rightmost (ie, below LED 5). As shown, the light output ratio Figure 16 The light output shown in the no-gap simulation shown is less. Additionally, there is more inconsistency in the lower portion of the uniform area of each LED 1722 compared to the no-gap simulation.

[0065] Simulations have shown that including air gaps to create light channels for corresponding LEDs can be an effective way to reduce light diffusion in a light guide.

[0066] Figure 25 is an example of a front plan view of a portion of a lighting unit 2500 according to another embodiment. Figure 10 The configuration is similar to Figure 25 LEDs 2522 are shown emitting light into the edge of a light guide 2526. Portions of the light guide 2526 between the locations of adjacent LEDs 2522 have been cut or removed to create air gaps 25263 in the channel region 25261. As previously described, air gaps 25263 can be long and narrow, extending in a direction perpendicular to the edge of the light guide 2526, with the LEDs 2522 emitting light into a confined channel for light emitted by the LEDs 2522. In some embodiments, air gaps 25263 can be filled with a light-absorbing material to ensure that light from one LED 2522 does not jump across air gap 25263 into the light channel created for an adjacent LED 2522. In some embodiments, the surface of the light guide material at the air gaps 25263 can be covered with a light-absorbing material. In some embodiments, the surface of the light guide material at the air gaps 25263 can be covered with a light-reflecting material.

[0067] In the illumination unit 2500, the light guide 2526 may further include a series of absorption lines 25264 located in the uniform region 25262. The absorption lines 25264 may be parallel to each other and extend across the light guide 2526 from the channel region 25261. The absorption lines 25264 may be located on the front surface of the light guide 2526, the back surface of the light guide 2526, or both. The absorption lines 25264 may absorb or block light that is typically diffused in the uniform region 25262. The absorption lines 25264 may be aligned with the air gaps 25263 such that they effectively assist in extending the illumination channels of the respective ones of the LEDs 2522. That is, the absorption lines 25264 may absorb or block light that would typically be diffused from one channel to an adjacent channel. The absorption lines 25264 may be provided individually or in combination with the air gaps 25263 to provide additional diffusion control over the entire length of the light guide 2526.

[0068] The absorption lines 25264 may be made of carbon black, paint, ink, or any other suitable material and color, and may be applied by spraying, brushing, printing, adhesive, or any other suitable method. The length and width of the absorption lines 25264 may be adjusted to minimize visibility and manage their light diffusion properties.

[0069] It should be understood that the foregoing description is merely illustrative of the present invention. Those skilled in the art may devise various alternatives and modifications without departing from the present invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications, and variations that fall within the scope of the appended claims.

Claims

1. An illumination assembly, comprising: A light guide; And A plurality of light sources configured to emit light into an edge of the light guide, wherein the light guide includes a plurality of air gaps arranged such that each air gap of the plurality of air gaps (i) is parallel to another air gap, (ii) is between adjacent light sources of the plurality of light sources, and (iii) extends in a direction in which light from the plurality of light sources propagates in the light guide.

2. The illumination assembly according to claim 1, wherein The light guide includes a diffusion region on a side closest to the plurality of light sources and a uniform region passing through the diffusion region, and The plurality of air gaps are in the diffusion region.

3. The illumination assembly according to claim 2, wherein The diffusion region is hidden from a viewer, and Light emitted from the plurality of light sources is mixed in the uniform region and can be viewed by the viewer.

4. The illumination assembly according to claim 3, wherein the light guide is flexible such that the diffusion region wraps around a background and is located behind the background.

5. The illumination assembly according to claim 1, wherein the plurality of air gaps are configured to substantially eliminate light traveling through the plurality of air gaps.

6. The illumination assembly according to claim 1, wherein the plurality of air gaps are filled with a light-absorbing material.

7. The illumination assembly according to claim 1, wherein a surface of the light guide at the plurality of air gaps is covered with a light-absorbing material.

8. The illumination assembly according to claim 1, wherein a surface of the light guide at the plurality of air gaps is covered with a light-reflecting material.

9. The illumination assembly according to claim 1, wherein the plurality of light sources include a plurality of light-emitting diodes.

10. The illumination assembly according to claim 1, wherein the light guide includes a protective layer provided on at least one main surface.

11. The illumination unit according to claim 1, wherein the light guide further includes a plurality of parallel light-absorbing lines respectively aligned with at least one air gap of the plurality of air gaps.

12. The illumination unit according to claim 11, wherein the plurality of light-absorbing lines are located on a main surface of the light guide.

13. The illumination unit according to claim 11, wherein the plurality of light-absorbing lines are located on two main surfaces of the light guide.

14. A decorative piece front-illuminated by the illumination assembly according to claim 1.

15. A display system, comprising: A reflective display; A background disposed behind the reflective display; And An illumination assembly configured to front-illuminate the reflective display, wherein the illumination assembly includes a light guide, a plurality of light sources configured to emit light into an edge of the light guide, and a plurality of air gaps arranged in a planar light guide such that each air gap of the plurality of air gaps (i) is parallel to another air gap, (ii) is between adjacent light sources of the plurality of light sources, and (iii) extends in a direction in which light from the plurality of light sources propagates in the light guide.

16. The display system according to claim 15, wherein, The light guide includes a diffusion region on a side closest to the plurality of light sources and a uniform region passing through the diffusion region, and the plurality of air gaps are located in the diffusion region.

17. The display system according to claim 16, wherein the diffusion region is hidden from the viewer, and the light emitted from the plurality of light sources is mixed in the uniform region and can be viewed by the viewer.

18. The display system according to claim 17, wherein the light guide is flexible such that the diffusion region wraps around the background and is located behind the background.

19. The display system according to claim 17, wherein, The diffusion region is located within the housing.

20. The display system according to claim 15, wherein the light guide further includes a plurality of parallel light absorption lines respectively aligned with at least one of the plurality of air gaps.

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