Light guide based side lighting assembly, elongated reinforcement structure, and receptacle - Patents.com

Abstract

A light guide-based side illumination assembly having an elongated side-emitting light guide, an optical protective coating surrounding the waveguide, an elongated base with the waveguide attached lengthwise along the elongated base via the optical protective coating, a reflector extending lengthwise along the base between the optical protective coating and the elongated base, and an elongated reinforcing structure embedded in the elongated base or attached to an outer surface of the elongated base and extending lengthwise along the elongated base. Other aspects are also described and claimed.

Description

[Technical field]

[0001] This patent application claims the benefit of the earlier filing date of U.S. Provisional Patent Application No. 62 / 952,065, filed December 20, 2020, entitled "Lightguide-Based Side-Lighting Assembly and Receptacle," and U.S. Provisional Patent Application No. 62 / 952,082, filed December 20, 2020, entitled "Lightguide-Based Side-Lighting Assembly Having Elongated Reinforcement Structures."

[0002] The subject matter described in this patent application relates to materials disclosed in: International Published Patent Applications Nos. PCT / IB2012 / 000617, entitled "Waveguide Apparatus for Illumination Systems"; PCT / IB2014 / 065386, entitled "Holder and System for Waveguide-Based Illumination"; and PCT / IB2016 / 057738, entitled "Optical Fiber Light Source Having a Composite Material Overcoat Structure."

[0003] Aspects of the present disclosure are: a light guide based side lighting assembly; and a receptacle that protects the assembly and facilitates manipulation of the assembly during manufacture as part of a larger or more complex lighting device or system. [Background technology]

[0004] Optical fibers are known to transmit optical signals from one fiber end to the other without significant loss. In other cases, the fibers are designed to leak the optical signal in a direction generally transverse to the propagation direction of the optical signal. This effect is typically the result of the interaction of the light (optical signal) with scattering structures built into the fiber, or as a result of the design of the particular fiber. Such scattering elements can be achieved: by adding elements such as impurities when drawing the fiber; by drilling holes in the fiber; or by mechanical, laser, or chemical processing of the fiber.

[0005] In some cases, luminescent materials are incorporated into the fiber core material, the cladding, or into a coating covering the outer surface of the fiber. The luminescent materials convert some or all of the propagating wavelengths to shorter or longer wavelengths, resulting in the desired illumination and wavelength delivered from the side of the fiber. The illumination schemes described above may need to be controlled, adjusted, or adapted by a suitable waveguide holder that can match the side of the waveguide (which may be an optical fiber) and exhibit selected reflective, absorptive, or transmissive properties to produce the appropriate shape of side illumination. The luminescent coated fiber can be embedded in a plastic overcoat structure of a holder with a polygonal base that allows the holder or the entire waveguide-holder assembly to fit into a mating fastening receptacle of a larger or more complex system. Summary of the Invention [Problem to be solved by the invention]

[0006] The lighting device is described in several aspects that can provide mechanical improvements in the operation and assembly methods of the elements of the lighting device, strengthen the side lighting assembly device (mechanically), and provide electrical and optical signals regarding the status of the lighting device. [Means for solving the problem]

[0007] In one aspect, the device includes a receptacle having an elongated groove formed therein with a first magnetic piece on the receptacle, e.g., embedded in the receptacle or attached to a surface of the receptacle, such as an outer surface defining the elongated groove. The device also includes a side illumination assembly comprising: an elongated side-emitting light guide; an elongated base to which the waveguide is attached lengthwise; and a second magnetic piece on the base, e.g., embedded in the elongated base or attached to a surface of the elongated base, such as an outer surface of the elongated base closest to the outer surface of the receptacle.

[0008] The first magnetic component on the receptacle may be: one or more permanent magnetic elements, e.g. strips, embedded in or attached to a surface of the receptacle, which may extend along the elongated groove of the receptacle or form a sequence along the elongated groove; magnetic particles embedded in, e.g. dispersed within, the receptacle; or electromagnets embedded in, or attached to a surface of the receptacle. The second magnetic component on the base may be: at least one ferromagnetic wire, extending lengthwise (along the length of the base); a permanent magnetic strip, extending lengthwise (along the length of the base); or magnetic particles embedded in the base, e.g. as a composite of magnetic particles in a polymer.

[0009] The groove has a cross-sectional size or shape such that it can receive the elongated base therein at a certain position, and the elongated base is held by magnetic attraction between the first magnetic part on the receptacle and the second magnetic part on the base. When the second magnetic part is one or more ferromagnetic wires, they serve to increase the mechanical strength of the side lighting assembly and enable the magnetic attraction to assist in "automatically" aligning and securing the side lighting assembly to the receptacle. The one or more ferromagnetic wires can also serve to carry analog or digital electrical signals, such as data signals, control signals, power, or power recovery, from one end of the side lighting assembly to the other, or the one or more ferromagnetic wires can function as mechanical gauges, for example to measure temperature or strain.

[0010] In another aspect, a side lighting assembly comprises: an elongated side emitting light guide; an elongated base to which the light guide is attached longitudinally; and an elongated reinforcing structure embedded in the base or attached longitudinally to a surface of the base, which serves to mechanically reinforce the side lighting assembly. The elongated reinforcing structure can be provided in place of a magnetic component that would otherwise be present on the base, and serves to relieve mechanical or thermal stresses during manufacturing of the side lighting assembly or when the side lighting assembly is manipulated (e.g., bent) to mate with a receptacle. Such stresses could otherwise damage elements of the side lighting assembly, for example, damaging the light guide, any coatings on the light guide, or a reflector. Alternatively, the elongated reinforcing structure can be provided in addition to the second magnetic component on the base, which can further strengthen the base mechanically or thermally.

[0011] The elongated reinforcing structure may be one or more flexible rods (e.g., wires) made of polymer or metal that extend lengthwise along the base. In another embodiment, the elongated reinforcing structure may be one or more optical fibers that may have a dual purpose to carry analog or digital optical signals, such as data or control signals, from one end of the side lighting assembly to the other, or may function as a mechanical gauge for strain or position measurement, such as a fiber Bragg grating sensor. The elongated reinforcing structure may also have a dual purpose as described above if it is one or more wires that can carry analog or digital electrical signals, or can function as a mechanical gauge for measuring temperature, such as a thermistor.

[0012] The above Summary of the Invention does not include an exhaustive list of all aspects of the present disclosure. The present disclosure is believed to include all systems and methods that may be implemented from all suitable combinations of the various aspects outlined above, as well as all systems and methods disclosed in the Detailed Description below and specifically pointed out in the claims filed with this application. Such combinations have certain advantages not expressly set forth in the Summary of the Invention above.

[0013] Aspects of the present disclosure are illustrated in the figures of the accompanying drawings, by way of example, and not by way of limitation. In the drawings, like reference numerals refer to like elements. It should be noted that a reference to "a" or "one" aspect of the present disclosure does not necessarily refer to that one aspect, but rather to at least one. Also, a given figure may be used to illustrate features of more than one aspect of the present disclosure, and not all elements of the figure may be required for a given aspect. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 shows an end view of an exemplary side-emitting light guide based lighting device in a cross section taken at a transverse plane. [Diagram 2] FIG. 2 is a top view of the lighting device, also showing the light sensor, light source, and electrical detector circuitry. [Diagram 3] FIG. 3 shows the coupling between an optical sensor and an optical waveguide. [Figure 4] FIG. 4 shows an end view of another exemplary side-emitting light guide based lighting device in a cross section taken at a transverse plane. [Diagram 5] FIG. 5 shows an end view of another exemplary side-emitting light guide based lighting device in a cross section taken at a transverse plane. [Figure 6] FIG. 6 shows an end view of yet another exemplary side-emitting light guide based lighting device in a cross section taken at a transverse plane. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. The scope of the present invention is not limited to only the illustrated parts, and the illustrated parts are merely for illustrative purposes, unless the shape, relative position, and other aspects of the parts described in the embodiments are clearly defined. Also, although many details are described, it should be understood that some embodiments of the present invention may be practiced without these details. In other examples, well-known structures and techniques are not illustrated in detail so as not to obscure the understanding of this description.

[0016] In accordance with several aspects of the present disclosure, and referring now to FIG. 1, an end view of an example of a lighting device is shown in a cross-section taken at a transverse plane. The lighting device includes a side lighting assembly 2, which includes an elongated side-emitting light guide 9 (e.g., an optical fiber) surrounded by an optical protective coating 15, which extends in a lengthwise direction as best seen in the top view shown in FIG. 2. FIG. 2 shows an example that is part of an automobile headlight, where the side lighting assembly 2 forms a serpentine pattern in a rough plane as shown, extending from a light source 12 at one end to a light sensor 11 at the other end. The light source 12 is configured to inject light into one end of the waveguide 9, which becomes propagating light along the side of the waveguide 9 and leaves the waveguide 9 at a location downstream of the light source 12. This is the illumination light that is emitted from its outer surface through the optical protective coating 15 (as shown by the wavy arrow in FIG. 1). The light sensor 11 detects the propagated light further downstream, for example at the other end of the light guide 9. The light sensor 11 can detect light "at the end" of the waveguide 9, which is the propagated light that is not emitted from the side of the waveguide 9 as the desired illumination. The light sensor 11 may also be omitted.

[0017] The lighting device also includes a receptacle 4 in which an elongated groove is formed. An outer surface 7 of the receptacle 4 defines the elongated groove and its cross-sectional shape. The elongated groove is sized and shaped to receive a base 10 of the side lighting assembly 2 therein. The groove in this example has a generally U-shaped cross-section (taken in transverse section), but the cross-section may alternatively be generally V-shaped or have a generally polygonal shape that may be more complex than a U or V-shape, and the cross-section may laterally support the base 10. In one aspect, the groove, and in particular its cross-section, may be fastened (or mated) to a cross-section of the base 10, such that the base 10 may be received within the groove in only one orientation (around the central axis of the waveguide 9). The receptacle 4 may be made of a stiffer material than the base 10, which allows the base 10 and side light assembly 2 as a whole to bend to match the shape or longitudinal contour of the groove. This facilitates assembly of the side light assembly and the receptacle. The receptacle may be made of a polymer (e.g., plastic), composite, or metal, and may be made of a stiffer material than the base 10, which may also be made of a polymer.

[0018] The first magnetic part 5 may be embedded in the receptacle 4 or (in the illustrated example) may be attached to an outer surface 7 of the receptacle 4 that defines the elongated groove, or may be attached to another surface of the receptacle. In one embodiment, the first magnetic part 5 extends lengthwise along the elongated groove and may be composed of one or more magnetic elements, such as one or more permanent magnetic strips that form a sequence or extend along the length of the groove. In the embodiment shown in FIG. 1, the one or more magnetic elements that make up the first magnetic part 5 are positioned along the bottom of the U-shaped cross-section of the receptacle 4. This is in contrast to the embodiment shown in FIG. 4, in which the one or more magnetic elements (that make up the first magnetic part 5) are positioned along the sides of the U-shaped cross-section.

[0019] The side lighting assembly 2 includes an elongated side-emitting light guide 9, an elongated base 10 to which the waveguide 9 is attached longitudinally via a protective coating 15, and a second magnetic part, which in one particular example is composed of a first ferromagnetic wire 6a and a second ferromagnetic wire 6b. The base 10 may be made of a polymer, e.g. plastic. The wires 6a, 6b may be embedded in the elongated base 10 as shown, or they may be attached to the outer surface of the elongated base, in either case extending longitudinally as shown. The side lighting assembly 2 may be fitted or placed in a groove in the receptacle 4, and then held in position longitudinally by the magnetic attraction between the first magnetic part 5 and the second magnetic part. In other words, the longitudinal movement of the side lighting assembly 2 is limited by the magnetic attraction. In the particular example shown, the side lighting assembly 2 is held in place or limited in width (horizontal or transverse) because the base 10 abuts the left and right side walls of the groove. In other words, the widthwise movement of the side lighting assembly is limited by the base 10 being sized and shaped to abut the left and right side walls of the groove. The magnetic attraction allows the side lighting assembly 2 to move freely laterally while outside the groove, and then directs it into the receptacle, at which point the magnetic attraction can be relied upon to "automatically" pull the side lighting assembly 2 further downward until a stop is reached. In the example shown, such stop is when the bottom of the base 10 abuts the groove. Once in this final position, the side lighting assembly 2 is held or limited in length by the magnetic attraction.

[0020] The ferromagnetic wires 6a, 6b increase the strength of the side lighting assembly, and such reinforcement can reduce mechanical or thermal stresses that may otherwise be present during manufacturing of the side lighting assembly or when manipulating the side lighting assembly into the receptacle, which may cause damage to elements of the side lighting assembly, such as the light guide, any coatings on the light guide, or the reflector. Additionally, the wires 6a, 6b can provide a magnetic attraction that helps to "automatically" align and secure the side lighting assembly 2 to the receptacle. In further embodiments described below, the ferromagnetic wires 6a, 6b can also carry analog or digital electrical signals, such as data signals, control signals, power, or power recovery, from one end of the side lighting assembly to the other.

[0021] 1, in the particular example shown, the first magnetic part 5 may include or be composed of one or more magnet elements. The ferromagnetic wires 6a, 6b are magnetically attracted to the one or more magnet elements of the first magnetic part 5. In this example, the first ferromagnetic wire 6a is positioned to the left of the vertical longitudinal center plane 14 of the side lighting assembly 2, and the second ferromagnetic wire 6b is positioned to the right of the vertical longitudinal center plane 14. The vertical longitudinal center plane 14 extends lengthwise along the side lighting assembly 2. Such positioning of the wires 6a, 6b aids in efficient utilization of the available volume within the base 10 and balances the magnetic attraction forces.

[0022] In one aspect of the disclosure, the ferromagnetic wires 6a, 6b are multipurpose and also function as electrical pathways from one end of the side lighting assembly to the other, as described below. Each ferromagnetic wire extends continuously in its length from a first end of the waveguide 9 to a second end of the waveguide 9 and is electrically conductive, so that it can carry an electrical signal, such as a "feedback signal" that is an indication of how the lighting device may be functioning. More specifically, as seen in the example of FIG. 2, at said first end, a light sensor 11 (such as a photodiode or phototransistor) may be added, configured to detect the propagating light in the waveguide 9. The first ferromagnetic wire 6a is coupled at one end to an electrical terminal of the light sensor 11 and at the other end to an electrical detector circuit 13. Similarly, the second ferromagnetic wire 6b is coupled at one end to another electrical terminal of the light sensor 11 and at the other end to an electrical detector circuit 13. The electrical detector circuit may be an analog comparator or may include an analog-to-digital converter as part of a digital comparison function, which compares the signal generated by the light sensor 11 and conveyed through one or more of the wires 6a, 6b to a set of one or more threshold values. Some action can then be taken based on the result of this comparison. For example, an electrical control circuit (not shown) may be coupled to the light source 12, which may control the amount of light injected by the light source into the waveguide 9 in response to the output of the electrical detector circuit 13 (e.g., the result of the comparison made thereby). For example, if the signal is below a minimum threshold, some optical aspect of the side-illumination waveguide 9 may be faulty, in which case the control circuit will turn off the light source 12. If the signal is above a minimum threshold but below an intermediate threshold, the side-illumination power is insufficient, in which case the control circuit will send a signal to the light source 12 to increase its output optical power. If the signal is above a maximum threshold, the side-illumination power is probably too high, in which case the control circuit will send a signal to the light source 12 to reduce its output power.Other types of analog or digital electrical signals may be carried by the ferromagnetic wires 6a, 6b, for example in this case the optical sensor 11 is omitted but the electrical signals carried by the ferromagnetic wires 6a, 6b are generated by another type of sensor or electrical signal generating circuitry.

[0023] More generally than the one shown in FIG. 1, the second magnetic part 2 on the side lighting assembly 2 may be one or more (including two or more) ferromagnetic wires, each of which extends lengthwise along the base 10. For example, there may be only a single ferromagnetic wire, which may be centered along the vertical plane 14, or there may be three wires (e.g. a single wire in the center and one wire on the left and one wire on the right, preferably symmetrical with respect to the vertical plane 14). In another embodiment not shown in FIG. 1, the second magnetic part may be one or more magnet elements, such as permanent magnet elements (embedded in the base 10 or attached to the surface of the base 10), which form a sequence or extend lengthwise along the base 10. Such a solution may also provide the advantage of mechanical reinforcement of the side lighting assembly 2, which would be provided by the ferromagnetic wires 6a, 6b. In yet another alternative (not shown in FIG. 1), the second magnetic component on the side lighting assembly 2 may be an electromagnet (e.g., having a coil formed in the base 10) or may be magnetic particles dispersed in the base 10, such as when the base 10 is made of a composite material of magnetic particles in a polymer.

[0024] As regards the first magnetic part 5 on the receptacle 4, this may be one or more magnetic elements embedded in the receptacle 4 or attached to a surface (e.g. outer surface 7) of the receptacle 4, for example forming a sequence or extending lengthwise along the base 10. The one or more magnetic elements may be permanent magnetic elements or they may be electromagnets. In yet another embodiment, the first magnetic part 5 may be magnetic particles embedded in the receptacle 4, for example dispersed within the receptacle 4.

[0025] 1 illustrates the side lighting assembly 2 as being comprised of an optical protective coating 15 attached to a base 10, the two elements may be made of the same material, such as a transparent polymer, and may be integrally formed as one piece, such as by an extrusion process. It can also be considered that the base 10 is an extension of the optical protective coating 15 that fits into a groove in the receptacle 4, or that the elongated reinforcing structure 20 is embedded in the optical protective coating or attached to an outer surface of the optical protective coating.

[0026] Reference is now made to FIG. 4, which shows an end view in a cross section taken in a transverse plane of another exemplary lighting device, also based on a side-emitting light guide 9. All arrangements and variations of the elements of FIG. 1 described above are applicable to the elements of the same reference numerals shown in FIG. 4, and any embodiment described above in relation to FIGS. 2, 3 is also applicable to the embodiment shown in FIG. 4, with the following exceptions: the first magnetic part 5 here comprises one or more magnet elements positioned along the side of the U-shaped cross section (of the receptacle 4) rather than along the bottom. Also, the first ferromagnetic wire 6a is now positioned above the horizontal longitudinal plane 17 of the base 10 (which is of course part of the side lighting assembly 2), and the second ferromagnetic wire 6b is positioned below the horizontal longitudinal plane 17. This may be referred to as a vertical or stacked arrangement of the wires 6a, 6b, as opposed to the horizontal or flat arrangement identified in FIG. 1. This vertical arrangement may have some advantages over the horizontal arrangement in that the diameter of the wires 6a, 6b can be chosen to be larger (for the same base 10 width), which entails higher stability and orientation adjustability. Note also that in Fig. 4, as shown, the first magnetic part 5 is partially embedded in the receptacle. Alternatives include full embedding of the part 5 (below surface 7), or attaching it to surface 7 so that it is completely outside the receptacle 4, as seen in Fig. 1.

[0027] Turning now to FIG. 5, this is an end view of another exemplary lighting device in a cross section taken in a transverse plane. Several embodiments are shown in this figure. In one embodiment, the elongated reinforcing structures 20 are on the base 10, for example embedded in the elongated base 10 as shown, or attached to the outer surface of the elongated base 10. The elongated reinforcing structures 20 are seen to extend lengthwise along the elongated base 10, and may be in addition to or instead of the ferromagnetic wires 6a, 6b. In other words, in a variation of what is shown in FIG. 5, the ferromagnetic wires 6a, 6b (as an example of the second magnetic component described above in connection with FIG. 1) are omitted from the side lighting assembly 2. This is possible because the elongated reinforcing structures 20 can be configured to mechanically reinforce the side lighting assembly themselves (without relying on the additional reinforcement provided by the ferromagnetic wires 6a, 6b). Such reinforcement reduces mechanical or thermal stresses that might otherwise be present during manufacture of the illustrated side lighting assembly 2 or when manipulating the side lighting assembly into a receptacle 4, which could cause damage to elements of the side lighting assembly, such as: the light guide 9; the optical protective coating 15; any coatings on the light guide, such as the light emitting layer 8 described below; or the reflector 16, also described below.

[0028] The elongated reinforcing structure 20 may be one or more flexible rods extending lengthwise along the base 10. As seen in the example of FIG. 5, there are two rods, respectively positioned symmetrically to the left and right of the vertical longitudinal center plane 14 extending lengthwise along the base 10. However, more generally, one or more such rods may be present on the base 10. The rods may be optical fibers, composite rods, metal rods (wires), or polymer rods. In the case of optical fibers, the rods may have a dual purpose (in addition to providing mechanical strength to the assembly 2) and thus carry analog or digital optical signals, e.g. data signals, control signals, from one end of the side-illumination assembly 2 along its length to the other end, or be part of a mechanical gauge for strain measurement or for position or orientation measurement, e.g. a fiber Bragg grating sensor. Such dual purpose is also possible when the elongated reinforcing structure 20 is one or more wires (e.g. capable of carrying analog or digital electrical signals, or functioning as part of a mechanical gauge, e.g. for performing temperature or strain measurements).

[0029] Much of the above description provided in connection with Figures 1-4 is also applicable to the similar elements seen in Figure 5, including the base 10 and the optical protective coating 15. For example, the optical protective coating 15 in the example of Figure 5 can be extruded simultaneously with the base 10 and the elongated reinforcing structures 20 embedded therein. However, Figure 5 also illustrates an alternative approach for attaching the optical protective coating 15 to the base 10, i.e., by adhering them together using an adhesive layer 18 (e.g., glue). Such an adhering operation may follow a separate operation of forming the optical protective coating 15 on the outer surface of the waveguide 9 or on the outer surface of the light emitting layer 8. It should be noted that if a reflector 16 is included as shown, one side of the reflector 16 may be secured to the outer surface of the protective coating 15 in a separate operation before the opposite side of the reflector 16 is adhered to the base 10 via the adhesive layer 18.

[0030] Referring now to Figure 6, another embodiment of the present disclosure is shown featuring an elongated reinforcing structure 20. In this case, the structure 20 is added to a version of the base 10 of a side lighting assembly 2 similar to that shown in Figure 1, where the ferromagnetic wires 6a, 6b are arranged flat rather than stacked as in Figures 4, 5. Some advantages of the embodiment shown in Figure 5 are also seen in Figure 6, namely that the "coated waveguide" (an integrated combination of the waveguide 9, optional light emitting layer 8 and optical protective coating 15) can be formed separately from the base 10 and then adhered to the base 10 via an adhesive layer 18, for example with an adhesive. This results in a lighting device (side lighting assembly 2 and receptacle 4) that is easier to assemble in terms of orientation and position due to magnetic attraction, and is more stable and rigid in terms of mechanics due to the addition of the elongated reinforcing structure 20. The variations described above in relation to Figure 1 (e.g., variations regarding the first magnetic part 5 on the receptacle 4 and variations regarding the second magnetic part on the base 10) are also applicable to the embodiment shown in Figure 6 where the same reference numbers are used in Figure 6.

[0031] In all of the above embodiments, for example, referring now to FIG. 1, the side lighting assembly 2 may further include a light emitting layer 8 surrounding the waveguide 9, and a reflector 16 between the protective coating 15 and the base 10. This combination produces side lighting as follows: The waveguide 9 may be an optical fiber having a core and a cladding, in which a primary propagated light is produced by a light source 12, e.g., a laser or a light emitting diode (LED), coupled to the fiber. The primary light propagates in the illustrated downstream direction along the central longitudinal axis of the fiber until a scattering zone (e.g., formed in the core of the fiber) scatters the primary light out of the fiber through the side of the fiber. Note that the light source 12 may be located away from the illumination space (illuminated by the side lighting assembly) since propagation through an upstream portion of the fiber can efficiently deliver the primary light from the light source to the scattering structure. The scattered radiation, or the escaped light, occurs in a direction generally transverse to the longitudinal axis of the fiber, either directional (forming a cone or lobe of light with a radial extent of less than 360°) or isotropically or omnidirectional (radiating with equal intensity all around the fiber). Examples of scattering zones that can produce such results can be found in International Publication No. PCT / IB2012 / 000617, filed March 28, 2012 (Waveguide Device for Illumination Systems). If directional side emission is particularly efficient, the reflector 16 may be omitted. Alternatively, other types of side-emitting optical fibers can be used.

[0032] The fiber has a luminescent layer 8 formed thereon, which may be a coating formed on the outer surface of the waveguide 9, and is made of a photoluminescent material that performs a wavelength conversion on the primary propagating light to a secondary light, resulting in side emitted light that includes the secondary light at a different wavelength than the primary light. The resulting side emitted light may exhibit a broader spectrum than the primary light, for example white light resulting from a combination of the unabsorbed primary light and the secondary light. Alternatively, the photoluminescent material of layer 8 and the wavelength of the primary light may be selected such that only a small amount of the primary light remains unabsorbed (e.g. detected by the photosensor 11), and thus the side emitted light exiting the fiber is dominated by the secondary light, which may be, for example, red or infrared light.

[0033] In another embodiment, there is no luminescent layer 8 as a coating formed on the outer surface of the waveguide because the photoluminescent material is directly incorporated into the waveguide 9 or is positioned outside of the side lighting assembly 2. In yet another embodiment, there is no photoluminescent material present within the waveguide 9 or as an outer coating, and therefore all of the side emitted light from the side lighting assembly 2 is primary light.

[0034] The light source 12 may be any suitable radiation source having one or more emitters. The source may have an incoherent and relatively broad spectrum, such as from a discharge lamp or a light emitting diode (LED). It may be an organic light emitting diode (OLED) or a quantum dot-based source. Alternatively, the source may be a coherent narrow spectrum light source, such as a laser emitting a single wavelength (also referred to herein as quasi-single wavelength), or may be a number of single wavelength lasers. The source is not limited to a particular part of the light spectrum. Examples include sources that emit light substantially in the ultraviolet, visible, or infrared parts of the spectrum.

[0035] The optical fiber may be any suitable optical fiber, such as a single-clad optical fiber, a multi-clad optical fiber, a photonic crystal optical fiber, or a microstructured optical fiber. The fiber may be passive, i.e., light propagates at approximately the same wavelength along the fiber, or active, i.e., the propagating light is partially or completely converted by luminescent species or materials implemented in the fiber core, cladding, or coating of the fiber (e.g., luminescent layer 8 shown in FIG. 1).

[0036] In yet another embodiment, the optical fiber may be replaced with another suitable waveguide, such as an optical conduit having a core medium but no cladding layer, for example a transparent rod.

[0037] The scattering structures may be particles, impurities or holes directly integrated during the fabrication of the waveguide (e.g. during drawing of an optical fiber). The scattering structures may be continuous or discontinuous laser-induced structures that can be formed by applying an external intense laser light to selected locations of the waveguide. The position, shape, size, scattering strength, tilt or orientation and periodicity of the scattering structures along or across the propagation direction of the guided light (transverse) can be selected by adapting the focus, intensity and position of an external treatment laser. In particular, by adapting these parameters, a desired radiation pattern can be obtained. The scattering structures may also be mechanical taps that are chemically or mechanically machined into the cladding of the fiber.

[0038] In another embodiment, the extracted light may follow a leaky mode of propagation within the waveguide 9. This leaky mode may arise due to an interaction between the propagating light and changes such as the gradient of the refractive index of the waveguide of the fiber, or changes in the radius or geometry of the fiber (which may be induced, for example, during the drawing process of the fiber).

[0039] The luminescent or photoluminescent species or materials, which may be in the waveguide itself or in the luminescent layer 8, may be any material that absorbs light at a particular wavelength and responsively re-emits light at another wavelength. For example, these materials may be one or more phosphors that re-emit light at a longer wavelength (down-converting phosphors), or one or more phosphors that re-emit light at a shorter wavelength (up-converting phosphors). These species may also be one or more types of quantum dots. In certain embodiments, the addition of photoluminescent materials is designed to efficiently generate white illumination light suitable for illuminating samples for quality inspection, the white light being a combination of the scattered and escaping "primary" light that has been wavelength-converted to "secondary" light, and any portion of the primary escaping light that has not been wavelength-converted.

[0040] The protective coating 15 and base 10 together hold the fiber in place and allow the assembly to be gripped. In some embodiments, the base 10 and the optical protective coating 15 may be made of the same material, such as an optically transparent polymer, e.g., a transparent polymer. The base 10 and the protective coating 15 (surrounding the light guide 9 and the emissive layer 8, if used) may be co-extruded so that they are formed together as a unitary part, with the reflector 16 embedded between the base and the optical protective coating 15 (if one is chosen to include it). Alternatively, an adhesive layer 18 (e.g., adhesive) may be used to bond the protective coating 15 or the reflector 16 to the base 10, as seen, for example, in FIG. 5.

[0041] The optical protective coating 15 can play an active role, i.e. it can directly or indirectly affect the shape, spectrum and / or polarization of the illumination pattern and its spatial distribution. In another embodiment, a part of the protective coating 15 can be made of an absorbing material so as to selectively suppress or block one or more parts of the emitted light, i.e. in a spatial sense. Alternatively, said absorbing material can be designed to selectively suppress or block a part of the spectrum of the emitted light, for example so that the resulting illumination pattern contains only selected wavelengths or colors. This can be combined with the reflection of the emitted light by the reflector 16.

[0042] The reflector 16 may be made partially or entirely of a reflective or diffusive material so as to diffuse or redirect a portion of the escaped light, or a portion of the spectrum of the escaped light, that is scattered out the side of the waveguide 9, as shown, for example, in FIG.

[0043] While specific embodiments have been described and illustrated in the drawings, it is to be understood that such embodiments are merely exemplary of the broad invention and are not limiting, and that the invention is not limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those skilled in the art, and the description is therefore to be regarded as illustrative and not limiting.

Claims

1. An elongated side-emitting optical waveguide; an optical protective coating surrounding the waveguide; Elongated base; a reflector extending longitudinally along the elongated base and disposed between the optical protective coating and the elongated base; and an elongated reinforcing structure comprising a flexible rod embedded in and extending longitudinally along said elongated base; Equipped with the elongated waveguide is attached to the elongated base along a length of the elongated base via the optical protective coating; the flexible rod is an optical fiber; A light guide based side lighting assembly.

2. The side lighting assembly of claim 1 , further comprising an adhesive layer that adheres the protective coating or the reflector to the base.

3. A side lighting assembly according to any one of claims 1 to 2, wherein the base and the protective coating are made of the same material.

4. A side lighting assembly according to any one of claims 1 to 2, wherein the base and the protective coating are made of different materials.

5. A side lighting assembly as described in any one of claims 1 to 3, wherein the elongated base is made of a polymer.

6. 2. The side lighting assembly of claim 1, wherein the flexible rod is a first flexible rod and the elongated reinforcing structure comprises a second flexible rod extending lengthwise along the base, the first flexible rod and the second flexible rod being symmetrically positioned to the left and right, respectively, of a lengthwise extending vertical longitudinal center plane.

7. A side lighting assembly as described in claim 6, wherein the second flexible rod is an optical fiber.

8. A side lighting assembly as claimed in any one of claims 1 and 3-7, wherein the base and the optical protective coating are made of one or more polymers and are co-extruded.

9. one elongated side-emitting light guide; an elongated optical protective coating surrounding the waveguide; and 1. A light guide based side illumination assembly comprising an elongated reinforcement structure consisting of two flexible rods embedded in and extending lengthwise along said optical protective coating, the flexible rods are a first flexible rod and a second flexible rod, the first flexible rod and the second flexible rod being symmetrically positioned to the left and right, respectively, of a vertical longitudinal center plane extending lengthwise along the side illumination assembly, the flexible rods being optical fibers; The side lighting assembly.

10. The side lighting assembly of claim 9, wherein the optical protective coating is a polymer.

11. 10. The side lighting assembly of claim 9, further comprising a magnetic component embedded in the optical protective coating or attached to an outer surface of the optical protective coating.

12. The side lighting assembly of claim 11 , wherein the magnetic component comprises magnetic particles embedded or dispersed within the optical protective coating.

13. 13. A side lighting assembly as claimed in claim 11 or claim 12, wherein a magnetic attraction between the magnetic part and another magnetic part on a receptacle holds the optical protective coating against the receptacle.

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