Patent Application
20190137678
The present invention relates to illumination assemblies, and more particularly to illumination assemblies for use in illuminating signs.
Decorative materials, such as those used in forming signs having text and/or graphics, are often illuminated by backlighting to enhance the design and/or draw attention to the materials. Examples of decorative materials used in these backlit designs include plastic films or paint. Many of these decorative materials appear to be opaque without backlighting, but can appear to “shine” or “glow” when backlit. The decorative materials are typically not completely transparent and as a result can require a significant amount of light in order to achieve the desired level and uniformity of backlight illumination.
The conventional way to backlight these decorative materials is to position multiple light sources, such as light emitting diodes (LEDs), behind the materials such that the emitted light is directed at the material. This conventional design can often result in bright spots in the backlit material corresponding to the location above each light source, which is not aesthetically desirable. One manner of addressing these bright spots is to print one or more layers of a light diffusing ink adjacent the decorative material to block the bright spots. However, this approach can reduce the overall efficiency of the optical system. In addition, printing can be difficult on many 3-dimensional surfaces and some materials cannot be printed on.
The aforementioned problems are overcome in the present invention in which an illumination assembly includes a light pipe configured to uniformly backlight a decorative material, and in particular those materials which appear opaque when unlit.
According to an embodiment, an illumination assembly includes a light pipe including a first portion including a light outlet and a second portion, opposite the first portion. The first and second portions define a body therebetween. A coupling hole is formed in the body and includes an opening in the second portion. The body can form a wall that defines an interior of the coupling hole and includes a light inlet. The coupling hole includes a central axis extending between the first and second portions, with the opening extending perpendicular to the central axis. A light engine is at least partially aligned with the opening and is adapted to direct light into the coupling hole. The light engine can include a light outlet disposed perpendicular to the central axis of the coupling hole. The light emitted by the light engine can enter the coupling hole through the opening and then enter the body through the light inlet. The light that enters through the light inlet is propagated through the body, away from the coupling hole, and is emitted through the light outlet in the first portion.
These and other advantages and features of the invention will be more fully understood and appreciated by reference to the description of the current embodiments and the drawings.
With reference to
This specification consistently uses the term “light pipe” to refer to the portion 12. The terms “light guide” or “wave guide” could be used interchangeably with “light pipe”. Light pipe in this specification is intended to include any device designed to transport light from a light source to a location at some distance from the light source with minimal, or at least modest, loss. Light is transmitted through a light pipe by means of total internal reflection.
Still referring to
The decorative layer 22 can be in the form of a film or panel and optionally having graphics adhered, etched, printed, painted and/or engraved thereon. The decorative layer 22 and the frame 14 can be configured such that the decorative layer 22 is held in place relative to the light pipe 12 by the frame 14. Alternatively, the sign 12 can be held in place using one or more mechanical fasteners (not shown). The decorative layer 22 can be made from a polymeric material, wood veneer, textile, metal, or non-metallic materials having a metallic or metallic-appearing finish. In one example, the decorative layer 22 is in the form of a single or multi-layer film or an ink or paint layer. The decorative layer 22 is optionally supported on the diffusing layer 24 or on a separate, transparent support layer.
The light pipe 12 includes a coupling hole 30 generally aligned with each light engine 20 for coupling the light emitted by the light engine 20 with the lens 60. The light pipe 12 optionally includes one or more extraction elements, such as optical aberrations 32, adapted to extract light through the outer surface 16 for backlighting the decorative layer 22. The optical aberrations may be etched, painted, engraved, embedded and/or adhered in or on the surface of the surface of the light pipe 12. The optical aberrations can be provided in patterns, non-limiting examples of which include dot patterns of offset rows, hatched circles, hatched boxes, lattice structures, chevron shapes, grooves, ribbing, and lines of varying depth. Other optical aberration patterns and configurations will be known to those skilled in the art.
The optional diffusing layer 24 can be any suitable single layer or multi-layer material for diffusing light emitted from the light outlet in the outer surface 16 of the light pipe 12. Non-limiting examples of suitable diffusing layer material includes paper, translucent acrylonitrile butadiene styrene (ABS), translucent polycarbonate (PC), translucent polyvinyl chloride (PVC), translucent acrylic, translucent polyethylene terephthalate (PET), translucent polybutylene terephthalate (PBT), translucent polypropylene, and translucent polyethylene.
The illumination assembly 10 can also include an optional backer layer 36 which is adapted to reflect light that exits through the inner surface 18 of the light pipe 12 back into the light pipe 12. The backer layer 36 can be any suitable single layer or multi-layer material for reflecting light back into the light pipe 12. Non-limiting examples of suitable backer layer materials includes paper, white ABS, white PC, white PVC, white acrylic, white PET, white PBT, white polypropylene, and white polyethylene.
The light engine 20 includes a light source adapted to emit illumination. Non-limiting examples of suitable light sources include a light emitting diode (LED), small incandescent light bulbs, electroluminescent lighting (EL), organic light emitting diodes (OLEDs), and/or other non-LED light sources. The number, spacing, voltage, current, intensity, and color of the light sources can be selected depending on the configuration of the illumination assembly 10 and the intended use.
The light engine 20 can include electronic components for controlling the electrical current through the light source. The light engine 20 may also contain electronic devices and circuitry to communicate with other light engines or devices in a system. This enables the light engine 20 to operate dynamically, that is, where color and brightness of the light changes over time to create a dynamic lighting experience. Multiple light engines 20 can be controlled together as part of a system to create moving and changing lighting effects. The light engine 20 may also include or provide for communication, either wired or wireless, to external devices such as personal cell phones, automotive body electronic control modules, or similar devices. This enables relatively easy customization and/or integrates the system with its surrounding environment and/or application.
Referring now to
The coupling hole 30 is incorporated into the light pipe 12 for coupling the light rays 40 emitted by the light engine 20 into the light pipe 12 for distribution of the light rays 40 radially through the light pipe 12. The coupling hole 30 includes a first or inlet opening 50 that extends perpendicular to a central axis 52 of the coupling hole 30. The coupling hole 30 optionally includes a second or outlet opening 54 opposite the inlet opening 50, along the central axis 52. The coupling hole 30 is defined by a wall 56 that is formed by the internal surfaces of the light pipe 12. The wall 56 includes a light inlet which allows light that enters the coupling hole 30 through the inlet opening 50 to enter the light pipe 12.
The light engine 20 can be coupled with the inlet opening 50 of the coupling hole 30 by a lens 60, as illustrated in
Still referring to
With reference now to
Referring again to
The lens 60 directs the light rays 40 emitted by the light engine 20 to the coupling hole inlet opening 50. At least a portion of the light rays 40 entering the coupling hole 30 hit the wall 56 defining the coupling hole 30 and are refracted into the light pipe 12. A portion of the light rays 40 that enter the light pipe 12 are trapped between the outer and inner surfaces 16 and 18 until they are extracted through the light outlet in the outer surface 16 where the extracted light backlights the decorative layer 22. Another portion of the light rays 40 may be extracted through the inner surface 18. The light extracted through the inner surface 18 can be reflected back into the light pipe 12 by the backer layer 36, where the light continues to scatter and refract through the light pipe 12. Another portion of the light rays 40 may hit the distal ends of the light pipe 12 and be refracted back into the light pipe 12 or leak out of the assembly 10.
Still referring to
The reflective cover 70 adjacent the outlet opening 54 can be adhered or painted onto the undersurface of the diffusing layer 24 or may be provided as a separate component from the diffusing layer 24. The reflective component 70 is preferably opaque, but in some embodiments may allow some light to pass through. In one example, the reflective cover 70 is in the form of a reflective paint applied over the outlet opening 54. When the reflective cover 70 is carried by the diffusing layer 24, the reflective cover 70 is only located adjacent the outlet opening 54 such that light extracted through the light outlet in the outer surface 16 is capable of entering the diffusing the layer 24. In general, when the illumination assembly 10 includes a reflective cover 70 for reflecting light that exits through the outlet opening 54, the reflective cover 70 is limited to covering the outlet opening 54 such that the light extracted through the light outlet in the outer surface 16 of the light pipe 12 is capable of backlighting the decorative material 22. In some embodiments, the outlet opening 54 is not covered by a reflective cover 70.
Positioning the light engine 20 along the central axis 52 of the coupling hole 30 such that the light engine 20 is positioned perpendicular to the central axis 52 facilitates coupling the emitted light with the light pipe 12 for distribution away from the coupling hole 30 and through the body of the light pipe 12. The angle of the coupling hole walls and the refractive index of the material forming the light pipe 12 can be selected such that light rays that directly hit the coupling hole walls 56 are immediately coupled into the light pipe 12 for distribution through the light pipe by total internal reflection (TIR). The configuration of the coupling hole 30 is also designed such that at least a portion of the light rays that do not enter the light pipe 12 through the coupling hole walls 56 on the first pass are recycled such that they are coupled into the light pipe 12 on a subsequent pass.
Referring now to
The data illustrated in
As illustrated in
When the angle 270 is less than 90 degrees, as illustrated in
Referring now to
The coupling hole walls 456 can extend at an angle to the central axis 452 that is less than 90 degrees such that the diameter of the outlet opening 454 is less than the diameter of the inlet opening 450. At least a portion of the light emitted by the light engine 20 hits the coupling hole walls 456 and is coupled into the light pipe 412. Light that is coupled into the light pipe 412 is distributed through the light pipe 412 by TIR and can be extracted through the light outlet in the outer surface 416 for backlighting a decorative layer (not shown) in a manner similar to that described above with respect to
As discussed above with respect to the embodiment of
The outlet end 668 can be inserted into the coupling hole 30 such that the lens outlet 664 is generally aligned with the coupling hole wall 56. Light emitted by the light engine 20 travels through the lens 660 where it is emitted through the lens outlet 664. At least a portion of the light emitted through the lens outlet 664 hits the coupling hole wall 56 and is coupled into the light pipe 12 for distribution through the light pipe 12. The dimensions of the coupling hole 30, the angle of the coupling hole wall 56 with respect to the central axis 52, and/or the angle of the lens outlet 664 with respect to a central axis 672 of the lens 660, can be selected to provide the desired coupling efficiency between the light emitted by the light engine 20 and the light pipe 12.
The lens 660 can be provided as a separate component for coupling light from the light engine 20 into the light pipe 12. In some embodiments, the lens 660 may be integrally formed with the light pipe 12.
The illumination assemblies described herein couple light emitted by multiple light sources into the light pipe such that the light can be distributed through the light pipe for backlighting a decorative material. Conventional designs for backlighting decorative materials rely on placing multiple light sources, such as LEDs, behind the decorative material such that the emitted light is directed at the decorative material. However, this configuration often results in non-uniform backlighting of the decorative material, including bright spots above each light source.
The illumination assemblies described herein provide a coupling hole within the light pipe which can be used to couple light emitted by a light source into the light pipe such that the light can be distributed away from the light source and through the light pipe. The light that is coupled into the light pipe through the coupling hole can be distributed away from the coupling hole and the light source through the light pipe for extraction through the light outlets formed in the light pipe. Spreading the light away from each individual light source can provide more uniform backlighting of the adjacent decorative material. Distributing the light more uniformly through the light pipe minimizes the appearance of undesirable bright spots in the decorative material and may provide sufficient backlighting with fewer light sources, thus increasing the efficiency of the illumination assembly.
The coupling hole described herein can be configured for use with planar light pipes as well as light pipes having a curved and/or 3-dimensional shape. The coupling hole can also be configured for use with materials having a range of different indices of refraction. The coupling hole can be used to couple light into the light pipe when the light engine is positioned adjacent the inlet opening or spaced from the inlet opening through a suitable lens. In this manner the coupling hole provides for increased flexibility in designing an illumination assembly for uniformly backlighting a decorative material.
The illumination assemblies described herein position the light source relative to the coupling hole such that the emission surface or light outlet of the light source is perpendicular to the central axis of the coupling hole. The configuration of the coupling hole, the light pipe material, and/or the configuration of the light pipe can be adjusted to provide the desired light coupling between the light emitted by the light source and the light pipe. For example, the dimensions of the coupling hole and/or the angle of the coupling hole walls can be adjusted to control the light coupling efficiency of the coupling hole based on the material of the light pipe and/or the configuration of the light pipe, such as whether the light pipe is planar or curved. Additional features, such as a reflective cover over the outlet opening of the coupling hole can be used to control the light coupling efficiency of the coupling hole. The coupling hole and light engine configurations described herein can be used to couple light into a light pipe for backlighting assemblies having a variety of different shapes, sizes, and materials.
The above description is that of current embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. To the extent not already described, the different features and structures of the various embodiments of the light pipes 12, 12′, 212, 312, 412, and 512 and coupling holes 30, 30′, 230, 330, 430, and 530 may be used in combination with each other as desired. That one feature may not be illustrated in all of the embodiments is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the various features of the different embodiments of the light pipes 12, 12′, 212, 312, 412, and 512 and coupling holes 30, 30′, 230, 330, 430, and 530 may be mixed and matched as desired to form new embodiments, whether or not the new embodiments are expressly disclosed.
This disclosure should not be interpreted as an exhaustive description of all embodiments of the invention or to limit the scope of the claims to the specific elements illustrated or described in connection with these embodiments. For example, and without limitation, any individual element of the described invention may be replaced by one or more alternative elements that provide substantially similar functionality or otherwise provide adequate operation. This includes, for example, presently known alternative elements, such as those that might be currently known to one skilled in the art, and alternative elements that may be developed in the future, such as those that one skilled in the art might, upon development, recognize as an alternative.
The invention is not limited to the details of operation or to the details of construction and the arrangement of the components set forth in the above description or illustrated in the drawings. The invention may be implemented in various other embodiments and practiced or carried out in alternative ways not expressly disclosed herein.
The phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. Further, enumeration may be used in the description of various embodiments. Unless otherwise expressly stated, the use of enumeration should not be construed as limiting the invention to any specific order or number of components. Nor should the use of enumeration be construed as excluding from the scope of the invention any additional steps or components that might be combined with or into the enumerated steps or components.
The disclosed embodiment includes a plurality of features that are described in concert and that might cooperatively provide a collection of benefits. The present invention is not limited to only those embodiments that include all of these features or that provide all of the stated benefits.
Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular.
Directional terms, such as “front,” “back,” “vertical,” “horizontal,” “top,” “bottom,” “upper,” “lower,” “inner,” “inwardly,” “outer” and “outwardly,” are used to assist in describing the invention based on the orientation of the embodiments shown in the illustrations. The use of directional terms should not be interpreted to limit the invention to any specific orientation.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US17/24681 | 3/29/2017 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62316970 | Apr 2016 | US |
