Light-embedded flexible filament

Abstract

A lighting device, a method for manufacturing a lighting device, and an automotive lighting system including the lighting device are described. The lighting device includes at least one light guide. The at least one light guide includes a cavity having a central portion. The at least one light guide is a parabolic collimator whose focal point coincides with the center of the cavity. The lighting device also includes an encapsulant having at least one opening through which light is emitted. The lighting device also includes at least one light-emitting element embedded in the cavity of the light guide. The light-emitting element has a coating oriented toward the at least one opening in the encapsulant.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 62 / 034181, filed June 3, 2020, and European Patent Application No. 20188191.9, filed July 28, 2020, the contents of which are incorporated herein by reference. [Background technology]

[0002] Light emitting elements, such as LEDs, may be disposed on a substrate that may also be used for electrical connections of the light emitting elements. For example, the light emitting elements may be disposed on a printed circuit board (PCB) that includes conductive tracks to supply electrical energy to the light emitting elements. However, substrates such as PCBs limit the shape of the lighting device, such as to shapes that are essentially flat for simple substrates. Summary of the Invention

[0003] A lighting device, a method for manufacturing the lighting device, and an automotive lighting system including the lighting device are described. The lighting device includes at least one light guide. The at least one light guide includes a cavity having a central portion. The at least one light guide is a parabolic collimator whose focal point coincides with the center of the cavity. The lighting device also includes an encapsulant having at least one opening through which light is emitted. The lighting device also includes at least one light-emitting element embedded in the cavity of the light guide. The light-emitting element has a coating oriented toward the at least one opening in the encapsulant. [Brief explanation of the drawings]

[0004] A more detailed understanding may be had from the following description, taken by way of example in conjunction with the accompanying drawings, in which: [Figure 1a] FIG. 1a is a schematic perspective view of an exemplary lighting device. [Figure 1b] FIG. 1b is a schematic cross-sectional view of the lighting device of FIG. 1a. [Figure 2a] FIG. 2a is a perspective view of a lighting module of the lighting device of FIG. 1a. [Figure 2b] FIG. 2b is a perspective view of the lighting module of the lighting device of FIG. 1b. [Figure 3] FIG. 3 is a schematic diagram of another example lighting device in cross section. [Figure 4a] FIG. 4a is a schematic cross-sectional view of the illumination device of FIG. 3 with light rays visualized from an optical simulation. [Figure 4b] FIG. 4b is a diagram of the intensity profile obtained as a result of an optical simulation performed according to the illumination arrangement of FIG. 4a. [Figure 5a] FIG. 5a is a schematic cross-sectional view of another exemplary illumination device with light rays visualized from an optical simulation. [Figure 5b] FIG. 5b is a schematic cross-sectional view of the illumination device of FIG. 5a with light rays visualized from an optical simulation. [Figure 6] FIG. 6 is a flow diagram of an exemplary method for manufacturing a lighting device. [Figure 7] FIG. 7 is a diagram of an exemplary vehicle headlamp system that may incorporate one or more of the embodiments and examples described herein. [Figure 8] FIG. 8 is a diagram of another exemplary vehicle headlamp system. DETAILED DESCRIPTION OF THE INVENTION

[0005] Examples of different lighting system and / or light emitting diode ("LED") implementations are described in more detail below with reference to the accompanying drawings. These examples are not mutually exclusive, and features found in one example may be combined with features found in one or more other examples to achieve additional implementations. Accordingly, it will be understood that the examples shown in the accompanying drawings are provided for illustrative purposes only and are not intended to limit the present disclosure in any way. Like reference numerals refer to like elements throughout.

[0006] Here, it will be understood that although terms such as first, second, third, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms may be used to distinguish one element from another. For example, a first element may be referred to as a second element, and a second element may be referred to as the first element, without departing from the scope of the present invention. As used herein, the term "and / or" may include any and all combinations of one or more of the associated listed items.

[0007] When an element, such as a layer, region, or substrate, is referred to as being "on" or extending "into" another element, it will be understood that it can be directly on or extending directly into the other element, or that intervening elements may also be present. In contrast, when an element is referred to as being "directly on" or extending "directly into" another element, it will also be understood that it can be directly connected or coupled to the other element, or it can be connected or coupled to the other element via one or more intervening elements. In contrast, when an element is referred to as being "directly on" or extending "directly into" another element, it will also be understood that it can be directly connected or coupled to the other element, or it can be connected or coupled to the other element via one or more intervening elements. When reference is made to an element being "directly connected" or "directly coupled," there are no intervening elements between the element and the other element. It will be understood that these terms are intended to encompass different orientations of the elements in addition to any orientation depicted in the figures.

[0008] Relative terms such as "bottom," "top," "upper," "lower," "horizontal," or "vertical" may be used herein to describe the relationship of one element, layer, or region to another element, layer, or region as shown in the figures. It will be understood that these terms are intended to encompass different orientations of the elements in addition to any orientation shown in the figures.

[0009] In automotive lighting, it may be desirable to style the luminous appearance of a lamp. For example, signaling functions such as turn signals, position lights, stop lights, and daytime running lights (DRLs) may be suitable for tailoring to the designer's desires. These signaling applications may be designed as line emitters in automotive lamps.

[0010] A product that can offer high styling freedom for line sources is 3D LED technology, a two-axis bendable line emitter. Line sources can enable high flexibility, luminous flux, uniformity, and compactness through the integration of dedicated LED-on-wire solutions using mid-power LED packages (also called front-ends) that can be assembled into elongated optical systems (also called back-ends).

[0011] This front-end technology, combined with an additional optical system, also called the back-end, is essentially a silicone-based elongated mix box with a dedicated diffuser to create a uniform light-emitting area. The front-end and back-end assembly can form an elongated LED module that can be mounted in an automotive lamp, car body, or even inside the car. Combining this light source with additional optics can even create a surface light.

[0012] Current LED architectures that enable such 3D shapes can meet the specifications of some automotive signaling applications. However, higher intensity or directionality than such architectures can provide is often required. Current 3D LED architectures are also particularly suited to unidirectional (or one-sided) emission, suitable as sources for blades and light guides or simply as direct emitters. However, in some cases, bidirectional or omnidirectional emission may be preferred (e.g., as part of a surface emitter), and current designs may not allow this. Optical integration may also be challenging with such 3D LED architectures.

[0013] The embodiments described herein may provide lighting devices, such as for automotive applications, and corresponding manufacturing methods that may provide desirable 3D shapes while enabling effective light etendue enhancement.

[0014] FIG. 1a is a schematic perspective view of an exemplary lighting device 2. The lighting device 2 can be, for example, an optical system. In the example shown in FIG. 1a, the lighting device 2 includes an encapsulant 10 and a light guide 4 disposed within the encapsulant 10. In some embodiments, the light guide 4 can be a parabolic collimator that can have a flat surface 28 (see FIG. 1b) disposed along an opening 14 of the encapsulant 10. In some embodiments, the flat surface can be opposite the parabolic cross section of the collimator such that light emitted by the at least one light-emitting element is guided toward the flat surface by the at least one light guide. The flat surface can be oriented toward the opening of the encapsulant such that the light is directed in this direction.

[0015] The recesses may include one or more mechanical reference features that allow the light emitting element to be embedded in the light guide in a manner defined by the mechanical reference features (e.g., orienting the light emitting element relative to the light guide). For example, the light guide 4 may include mechanical reference elements 12 on the right and left sides of the light guide to allow the light guide 4 to be secured within the opening 14 of the encapsulant 10. Correspondingly, the encapsulant 10 may have respective recesses, such as slots, into which the mechanical reference elements 12 of the light guide 4 may be inserted. The light guide 4 may also have, at least partially, a recess 6 (see FIG. 1b) into which the lighting module 22 may be embedded. The lighting module 22 may also be inserted into the recess, another portion of which is shown on the upper side of the encapsulant 10. In some embodiments, the securing feature may be provided by one or more mechanical reference features of the encapsulant.

[0016] The encapsulating material may include or have one or more mechanical reference features that allow the light guide to be positioned relative to the encapsulating material in a manner defined by the mechanical reference features (e.g., orienting the light guide with respect to a particular rotation and / or orienting the position of the light guide relative to the encapsulating material). Such one or more mechanical reference features of the encapsulating material may be, for example, a slot, a gap, or a void. Such one or more mechanical reference features of the encapsulating material may, for example, have a particular shape. Correspondingly, the light guide may have a corresponding mechanical reference feature, which may, for example, allow a form-fit between the mechanical reference feature of the light guide and the mechanical reference feature of the encapsulating material.

[0017] In embodiments, a parabolic collimator may be parabolic. As used herein, this will be understood to mean that the collimator has a parabolic cross section, at least in its main portion. This does not exclude that the collimator may include one or more features, for example, for mechanical connection to one or more additional elements (e.g., encapsulation material) that do not conform to the parabola.

[0018] According to some embodiments, the collimator may comprise a flexible material. The collimator may be made of a flexible material such as optical grade silicone. In this way, applications such as automotive lighting, such as tail lights, stop lights, indicator lights, DRLs, etc., can be designed with great freedom in terms of their form and shape.

[0019] A light guide, such as light guide 4, can transport light via a specific route over a predetermined distance to a defined light-emitting surface (e.g., with minimal losses). Thus, the radiation characteristics of the light emitted from the light guide can be precisely controlled, for example, to meet regulatory requirements. For this purpose, appropriate transmittance and / or reflectance of the light guide's surface can be tailored. Light guides can be made from any suitable optically transparent material.

[0020] Figure 1b is a schematic cross-sectional view of the lighting device 2 of Figure 1a. In the example shown in Figure 1b, the lighting device 2 comprises a lighting module 22 including a flexfoil 16 on which a plurality of light-emitting elements 8 are arranged. The flexfoil 16 may be covered with a phosphor coating 18 (not marked in Figures 1a and 1b) to convert the wavelength of the light emitted by the light-emitting elements 8.

[0021] A flex foil may refer to a flexible strip that may include a number of conductor tracks provided by the flexible strip. The conductor tracks allow one or more light emitting elements to be connected to one another and to a power source, which may also be connected to drive one or more light emitting elements to emit light. The flex foil is very thin and can be bent in at least three different directions. The flex foil may represent a carrier on which at least one light emitting element can be arranged. The flex foil may have an elongated shape so that multiple (e.g., at least two) light emitting elements can be arranged on the flex foil.

[0022] Therefore, the flex foil can be a carrier for the light emitting element. In this way, the light emitted by the light emitting element can be guided in one or more directions by the light guide. For example, the light guide can guide the light emitted by the light emitting element so that the light is evenly distributed in a particular direction.

[0023] When the light guide 4 is inserted into the encapsulant 10, there may be an air gap 20 between the light guide 4 and the encapsulant 10. There may also be another air gap (not shown in Figures 1a and 1b) between the lighting module 22 and the light guide 4. This latter air gap may be between the coating 18 covering the flex foil 16 and the light guide 4.

[0024] The lighting module 22 may represent a lighting module (e.g., a filament 3D LED light source, also referred to as a front-end architecture) of the lighting device 2. The encapsulant 10 may, for example, be a white mix box, which also represents the back-end architecture of the lighting device 2. The lighting module 22 (e.g., a filament) may be inserted or integrated into this mix box, which is the front-end architecture, as shown in Figures 1a and 1b. In this way, the light guide 4 may be optically coupled to the light emitting elements 8 of the lighting module 22.

[0025] The encapsulant 10 may further provide protection for the light guide 4 and the lighting module 22. In addition, the encapsulant 10 may avoid stray light being emitted in the direction of the encapsulant 10 rather than its opening 14, because this light may be blocked by the encapsulant 10 or reflected in the direction of the opening 14. In this way, the lighting device 2 may have increased optical efficiency.

[0026] Because emitted light can also escape toward the bottom of the encapsulant, it may be desirable for the encapsulant to have highly reflective properties. Light passing through the light guide in a direction encompassed by the encapsulant can then be reflected back into the light guide, which can then direct the light toward the opening. The illumination device 2 can strongly peak the intensity of the light emitted by the illumination device. Stray light, or light not directed toward the opening by the light guide, can be addressed by reflecting this light by the encapsulant.

[0027] For example, the encapsulation material may have a reflectivity greater than 95%, at least in part, to achieve adequate encapsulation efficiency. Highly reflective silicone materials typically filled with metal oxides, such as TiO2, may be used. The amount of these materials may range from 5 to 30% by weight. Too high a particle amount can reduce the flexibility of the silicone and even make it brittle. To enhance reflectivity, the encapsulation material may represent a white mix box. Therefore, the material from which the encapsulation material is made may represent a white color with the above reflectivity. The effective etendue may be increased by the compromise between efficiency and beam width that may be made possible by the exemplary embodiments described herein. The encapsulation material can reflect light in all directions. The light guide can collimate the light as much as possible because stray light that is not collimated in the desired direction (e.g., not directly collimated) can be captured by the encapsulation material and reflected through the light guide and through the aperture. This light can be emitted in a broader manner than light that emerges directly through the aperture.

[0028] The light guide 4, in combination with the lighting modules 22, can be considered to represent a classical total internal reflection (TIR) ​​collimator (described in more detail below with respect to FIGS. 2a and 2b). Such a collimator can be an optical element designed to collimate light emitted by the light-emitting elements in at least one main direction. This may not exclude that some light emitted by the light-emitting elements can be emitted in directions different from such main direction. The collimator can have one or more optically smooth surfaces to promote optimal TIR conditions, if necessary. Each lighting module 22 can emit hemispherically (rather than omnidirectionally as shown in the embodiments of FIGS. 3, 4a, and 5a).

[0029] According to some embodiments, a plurality of light-emitting elements may be arranged along a longitudinal direction of the lighting device. The lighting device may have a longitudinal direction that may correspond to the longest dimension of the lighting device. The light-emitting elements may be arranged at least partially along the longitudinal direction relative to one another. The light-emitting elements may be spaced apart along the longitudinal direction, for example, at regular or irregular intervals. For example, the lighting device may substantially have the shape of a strip, for example, having a substantially constant cross-section. Such an arrangement of light-emitting elements allows the lighting device to be configured as a semi-finished product essentially endless or one-dimensionally, thereby significantly reducing production costs and allowing the length of the lighting device to be selected after the semi-finished product is produced.

[0030] In some embodiments, the flex foil may be at least partially coated. The coating may define at least one wavelength to which the light emitted by the light-emitting element is converted. In some embodiments, the coating may be a phosphor coating, although those skilled in the art will understand alternatives to phosphors. The phosphor coating acts as a wavelength converter, making it possible, for example, to change the frequency of visible light. It will be understood that in addition to or instead of a phosphor coating, respective coatings may be used that block light in certain directions and / or define certain wavelengths and / or intensities to which the emitted light is converted.

[0031] To control the color or distribution of emitted light, a coating of phosphor in silicone or metal oxide in silicone (e.g., TiO2) can be applied as an optically functional coating to the light-emitting element disposed on the flex foil. The coating (e.g., phosphor in silicone or metal oxide in silicone) can be applied to one or both sides of the flex foil. This can be done on one side to provide a hemispherical radiation source. If a transparent or translucent flex foil is used and the phosphor in silicone or metal oxide in silicone is applied to both sides, an omnidirectionally emitting flex foil filament can be obtained. Therefore, if the flex foil has at least one light-emitting element disposed on both sides, the light emission can be omnidirectional. The flex foil can be either transparent or opaque. Such omnidirectional light emission can also be achieved if the flex foil is transparent and has at least one light-emitting element on one side rather than both sides. And, even if at least one light-emitting element is disposed on one side of the flex foil, the light emission can be omnidirectional because it can penetrate the transparent flex foil. The flex foil and at least one light emitting element that provides omnidirectional light emission may also be called a flex foil filament. Such kind of flex foil filament is usually applied in retrofit light bulbs.

[0032] Alternatively, the flex foil and at least one light-emitting element providing hemispherical light emission may be referred to as a hemispherical light-emitting flex foil. Such a hemispherical light-emitting flex foil may emit light from one side of the flex foil. Therefore, such a hemispherical light-emitting flex foil may have a blocking layer on the other side, or may be opaque (e.g., a solid layer), or may not be transparent, so that light emission is directed to one side of the flex foil. The blocking layer or solid layer may ideally be reflective for efficiency reasons. In this way, light loss is minimized and at least a portion of the reflected light can be emitted in the intended direction. According to some embodiments, the flex foil and coating may form a hemispherical shape, and the flex foil together with the coating may be at least partially embedded in an encapsulant material and further at least partially embedded in at least one light guide. This may enable hemispherical light emission, for example, when multiple light-emitting elements are arranged on the flex foil and correspondingly powered to emit light. A power source may be connected via conductive tracks provided on the flex foil. The hemispherical shape can prevent light from being emitted in the direction of the bottom opposite the top surface where the light emitting elements are located. Furthermore, to further enhance the blocking of light in the direction of the bottom surface of the flex foil, an additional coating may optionally be applied to the bottom surface of the flex foil that blocks light emitted to the bottom surface.

[0033] According to some embodiments, the encapsulant may surround at least one light guide on three sides such that light emitted by the at least one light emitting element is blocked or reflected by the encapsulant. Thus, when the light guide is attached to the encapsulant, the encapsulant may surround the light guide on three sides when viewed from a cross-section of the light guide. In this way, light may be emitted by the light emitting element in a direction that is not surrounded or covered by the encapsulant.

[0034] 2a and 2b are perspective views of a lighting module 22 of the lighting device 2 of FIGS. 1a and 1b. In the example shown in FIG. 2a, the lighting module 22 includes a flex foil 16 coated with a phosphor coating 18. The flex foil 16 may be a flex foil strip. Multiple light-emitting elements may be disposed on the flex foil 16. The multiple light-emitting elements may be connected together by conductive tracks provided by the flex foil 16. The phosphor coating 18 may be applied (e.g., molded or applied) to the top surface of the flex foil 16, as shown in FIG. 2a. This may enable hemispherical light emission when the multiple light-emitting elements are powered. A power source (not shown in FIGS. 2a and 2b) may be coupled to the light-emitting elements via the conductive tracks. No light is emitted from the bottom side of the flex foil 16. To enhance the blocking of light towards the bottom side of the flex foil 16, optionally, an additional light blocking coating may be applied to the bottom side of the flex foil 16 that blocks light from being emitted at the bottom side.

[0035] The lighting module 22 including the flex foil 16 and the coating 18 may form a hemispherical shape, and the flex foil 16 together with the coating 18 may be intended to be at least partially embedded in the encapsulant material 10, which in turn may be at least partially embedded in at least one light guide 4. This is shown, for example, by the exemplary embodiment of the lighting device 2 in Figures 1a and 1b.

[0036] In the example shown in FIG. 2b, the lighting module 22 includes a flex foil 16 coated on both sides (e.g., top and bottom sides) with a phosphor coating 18. This is indicated in FIG. 2b by the phosphor coating 18 being marked with two corresponding reference characters. Multiple light-emitting elements may be disposed on the flex foil 16. The multiple light-emitting elements may be connected by conductive tracks. For example, covering both sides of the flex foil 16 with the phosphor coating 18 may enable omnidirectional light emission when the multiple light-emitting elements are driven. Thus, the flex foil 16 of FIG. 2b may emit light evenly on all sides when powered. It will be understood that coatings other than phosphor coatings are possible, for example, to adapt the lighting module 22 to specific optical requirements and / or applications.

[0037] Figure 3 is a schematic cross-sectional view of another exemplary lighting device 2. In the example shown in Figure 3, the lighting device 2 includes a light guide 4 having a recess 6. In the example shown, the recess 6 is a cavity, and the light guide 4 represents an optical element, with the cavity being an extrusion hole. The cavity can be used to insert a lighting module 22, as described above, such as an LED filament, into the cavity, as shown in Figures 2a and 2b.

[0038] The light guide may have an elongated shape, and the recess may be elongated and extend along the entire length of the light guide (e.g., along the length of the light guide). The collimator may at least partially surround the light emitting element. In some embodiments, the collimator may completely surround the light emitting element.

[0039] The collimators may have their respective foci in the recesses. As shown in the illustrated example, the focus F of the parabolic collimator representing the light guide 4 is in the center of the cavity 6. The lighting module 22 may be oriented in the cavity so that the side including the coating 18 (see FIG. 2a) faces the opening 14 of the encapsulant 10. This is illustrated in FIG. 3 by the two directions D1 and D2. D1 and D2 represent two arrows indicating the possible directions in which light may be emitted by such a hemispherical lighting module 22 embedded in the recess or cavity 6. Thus, from the viewpoint of a viewer of FIG. 3, light may be emitted to the bottom, left, and right of the flex foil 16. Also, there may be air gaps 20 both between the light guide 4 and the encapsulant 10 and between the lighting module 22 and the inner wall of the recess 6 in the form of a cavity (not shown).

[0040] According to some embodiments, when the light-emitting element is embedded in a recess in the light guide, a gap 20 may be formed between the light-emitting element and the light guide. When the light-emitting element is disposed on another element, such as a flex foil, a gap may be formed between at least a portion of the element (e.g., the flex foil) on which the light-emitting element is disposed and the recess in the light guide. Therefore, at least a portion or a part of the recess in the light guide is not in direct contact with the light-emitting element or another element on which the light-emitting element is disposed. Such a gap may enable a good optical collimation effect. For example, such a gap may act as an interface. In practice, such a gap may always be formed due to, for example, the surface roughness of a coating covering a flex foil containing the light-emitting element (the aforementioned features together may form a lighting module). A gap may be formed between the lighting module or its coating and at least one light guide. Also, the gap may provide a peak intensity distribution of the light. For example, in applications requiring a high intensity level in a specific direction (e.g., brake lights or rear turn signals), a collimator may provide such a required peak intensity distribution. To enable the peak intensity distribution, a gap between the lighting device and the light guide may be essential. The peak intensity distribution can result from the combination of an air gap and the collimator shape of the light guide, such as a parabolic shape. The air gap itself provides little collimation. Without the air gap, the TIR condition may not be met for other surfaces of the light guide (e.g., rays may start from the medium itself, which may result in worse TIR conditions than with the air gap). Therefore, the absence of the air gap can reduce the collimating effectiveness of a parabolic collimator light guide.

[0041] The cavity may be a circular cavity. In some embodiments, the cavity may be a hole in the bottom of the light guide (e.g., drilled in the longitudinal direction of the light guide). The light emitting element or lighting module may be inserted into a recess represented by, for example, a circular cavity. The light guide material may completely surround the light emitting element or the flex foil containing the light emitting element. The cavity may extend along the longitudinal axis of the collimator.

[0042] Alternatively, the recess may be at the bottom of the light guide, and the at least one light emitting element may not be completely surrounded by the light guide when embedded in the light guide. If the recess is not a cavity, the encapsulant may provide a fastening function that allows the light emitting element to be held in a specific location relative to the light guide in order to at least partially embed the light emitting element in the light guide. It will thus be understood that the encapsulant may also provide a fastening function that allows the encapsulant and the light guide to be connected.

[0043] The anchoring features may provide one or more mechanical reference functions. For example, the anchoring features may be in the form of wings or small, thin extensions on opposite sides of the light guide. At least one anchoring element may also be used to orient the light guide relative to the encapsulant.

[0044] 4a is a schematic cross-sectional view of the lighting device 2 of FIG. 3 with light rays visualized from an optical simulation. In the example shown in FIG. 4a, the light rays are indicated by black lines that are guided by the light guide 4. At least where the light guide 4 is located, the encapsulant 10 may be reflective. Light emitted by the lighting module 22 that is not directed by the parabolic collimator through its flat surface 28 towards the opening 14 of the encapsulant 10 may be reflected towards the light guide 4. In this way, the optical efficiency of the lighting device according to the first embodiment may be increased.

[0045] 4b shows an intensity profile obtained as a result of an optical simulation performed according to the illumination device of FIG. 4a. The intensity profile 26a is strongly sharpened by the parabolic collimator that includes the illumination module in the recess 6, which is also the collimator's focal point F. It can also be seen that the candela profile 26b minimizes stray light, especially at emission angles below and above 90°. Thus, the illumination device 2 according to the first embodiment allows for highly efficient emission, since almost all of the light emitted by the illumination module 22 is directed in the intended direction towards the opening in the encapsulant 10.

[0046] An intensity profile 26a with a high peak intensity in HV (on axis) is shown in Figure 4a. Because the light module 22 has the property of emitting light in all directions, the light guide in the form of a parabolic collimator collimates in only one direction.

[0047] Figure 5a is a schematic cross-sectional view of another exemplary lighting device 2 with visualized light rays from an optical simulation. In the example shown in Figure 5a, the light guide 4 is not surrounded by an encapsulant (see Figures 3 and 4a). As in the example of Figure 4a, the lighting module 22 may be integrated into a recess 6, which may be a cavity. As such, the lighting module 22 may be completely surrounded by the light guide 4. Alternatively, the light guide 4 may be in the form of a parabolic collimator with a focal point F in the center of the cavity.

[0048] In the example shown in Figure 5a, light rays are indicated by black lines that are guided by the light guide 4. It will be appreciated that some light emitted by the lighting module 22 may be directed by the parabolic collimator in a direction different from its planar surface 28.

[0049] FIG. 5b illustrates an intensity profile obtained as a result of an optical simulation performed according to the lighting device 2 of FIG. 5a. In the example shown in FIG. 5b, the encapsulant 10 (e.g., a white mix box) is omitted. Therefore, collimation may rely entirely on the TIR effect of the silicone / air interface (e.g., air gap) between the lighting device 22 and the light guide 4 on a parabolic curve. For example, in contrast to the embodiment shown in FIG. 4a, the design of the embodiment shown in FIG. 5a may be simpler. However, using the light guide as an optical system may result in the light guide being insufficiently protected against, for example, dust / scratches. The light guide 4 of the embodiment shown in FIG. 5a may still include mechanical reference features (shown as ears in FIG. 5a). Such mechanical reference features may still be necessary, for example, for mounting the lighting device 2 with the embedded lighting module 22 to another element, such as a diffuser, lens, or reflector, to name a few non-limiting examples.

[0050] FIG. 6 is a flow diagram of an exemplary method for manufacturing a lighting device. In the example shown in FIG. 6, the method includes providing a light guide including a cavity (602). In some embodiments, the cavity has a central portion, and the light guide may be a parabolic collimator whose focal point coincides with the central portion of the cavity. An encapsulant material may be provided (604). In some embodiments, the encapsulant material may include at least one aperture through which light is emitted. At least one light emitting element may be provided (606). The at least one light emitting element may be embedded in a cavity within the light guide (608). In some embodiments, the light emitting element may include a coating oriented toward the at least one aperture of the encapsulant material. In some embodiments, the light emitting element may be embedded in the cavity by, for example, mechanically inserting the light emitting element into the cavity.

[0051] According to some embodiments, the method may also include at least partially encapsulating the at least one light guide with at least one encapsulant. The encapsulant may include at least one opening through which light can be emitted. For example, at least one light guide having a light emitting element may be encapsulated with at least one encapsulant. The light guide may be encapsulated with the encapsulant such that the encapsulant at least partially surrounds the light guide. The encapsulant may include an opening through which light can be emitted when the light guide is positioned against the encapsulant.

[0052] This may be done by inserting the light guide containing the light emitting element into the encapsulant, for example, through an opening in the encapsulant. One or more of the steps may be performed by a pick-and-place process. Additionally or alternatively, at least some of the steps may be done manually or automatically using specialized tools.

[0053] Alternatively, multiple light emitting elements may be disposed (e.g., attached) to a flex foil strip. The flex foil may be bendable. The light emitting elements on the flex foil strip may be coated, for example, with phosphor, as described above. This entire arrangement may also be bendable. The encapsulant may be made from or include silicone, so that the encapsulant may also be bendable. The flex foil with multiple light emitting elements is encapsulated with the encapsulant to form a completed lighting device.

[0054] 7 is a diagram of an example vehicle headlamp system 700 that may incorporate one or more of the embodiments and examples described herein. The example vehicle headlamp system 700 shown in FIG. 7 includes a power line 702, a data bus 704, an input filter and protection module 706, a bus transceiver 708, a sensor module 710, an LED direct current to direct current (DC / DC) module 712, a logic low dropout (LDO) module 714, a microcontroller 716, and an active headlamp 718.

[0055] The power line 702 has an input for receiving power from the vehicle, and the data bus 704 may have inputs and outputs through which data may be exchanged between the vehicle and the vehicle headlamp system 700. For example, the vehicle headlamp system 700 may receive instructions, such as instructions to turn on turn signals or turn on headlamps, from elsewhere in the vehicle and transmit feedback to elsewhere in the vehicle as needed. A sensor module 710 may be communicatively coupled to the data bus 704 and provide additional data to the vehicle headlamp system 700 or elsewhere in the vehicle, relating to, for example, environmental conditions (e.g., time of day, rain, fog, or ambient light levels), vehicle status (e.g., parked, moving, speed or direction of travel), and the presence / location of other objects (e.g., vehicles or pedestrians). A headlamp controller separate from any vehicle controller communicatively coupled to the vehicle data bus may also be included in the vehicle headlamp system 700. In FIG. 7 , the headlamp controller may be a microcontroller, such as a microcontroller (μc) 716. The microcontroller 716 may be communicatively coupled to the data bus 704.

[0056] The input filter and protection module 706 is electrically coupled to the power line 702 and may support various filters to, for example, reduce conducted emissions and provide power immunity. Additionally, the input filter and protection module 106 may provide electrostatic discharge (ESD) protection, load dump protection, alternator field decay protection, and / or reverse polarity protection.

[0057] An LED DC / DC module 712 may be coupled between the input filter and protection module 706 and the active headlamp 718 to receive the filtered power and provide a drive current to power the LEDs of the lighting device in the active headlamp 718. The LED DC / DC module 712 may have an input voltage of 7 to 18 volts, with a nominal voltage of approximately 13.2 volts, and an output voltage (e.g., 0.3 volts) that may be slightly higher than the maximum voltage of the light emitting elements in the lighting device (e.g., as determined by adjustments for operating conditions due to load, temperature, or other factors and coefficients or local calibration).

[0058] A logic LDO module 714 may be coupled to the input filter and protection module 706 to receive filtered power. The logic LDO module 714 may also be coupled to the microcontroller 716 and the active headlamp 718 to power electronics within the microcontroller 716 and / or CMOS logic, such as the active headlamp 718.

[0059] The bus transceiver 708 may have, for example, a universal asynchronous receiver transmitter (UART) or a serial peripheral interface (SPI) interface and may be coupled to a microcontroller 716. The microcontroller 716 may convert vehicle inputs based on or including data from the sensor module 710. The converted vehicle inputs may include video signals that can be transferred to an image buffer within the active headlamp 718. Additionally, the microcontroller 716 may load a default image frame and test for open / short pixels during startup. In embodiments, the SPI interface may load a CMOS image buffer. The image frame may be a full frame, a differential frame, or a partial frame. Other functions of the microcontroller 716 may include a control interface monitoring CMOS status, including die temperature, in addition to logic LDO outputs. In embodiments, LED DC / DC outputs may be dynamically controlled to minimize headroom. In addition to providing image frame data, other headlamp functions may also be controlled, such as complementary use in combination with side marker or turn signal lights and / or activation of daytime running lights.

[0060] Figure 8 is a diagram of another example vehicle headlamp system 800. The example vehicle headlamp system 800 shown in Figure 8 includes an application platform 802, two lighting devices or systems 806 and 808, and secondary optics 810 and 812.

[0061] Illumination system or device 808 may emit light beam 814 (shown between arrows 814a and 814b in FIG. 8 ). Illumination system or device 806 may emit light beam 816 (shown between arrows 816a and 816b in FIG. 8 ). In the embodiment shown in FIG. 8 , secondary optics 810 is adjacent to illumination system or device 808, and light emitted from illumination system or device 808 passes through secondary optics 810. Similarly, secondary optics 812 is adjacent to illumination system or device 806, and light emitted from illumination system or device 806 passes through secondary optics 812. In an alternative embodiment, secondary optics 810 / 812 are not provided in the vehicle headlamp system.

[0062] The secondary optics 810 / 812, if included, may be or may include one or more light guides. The one or more light guides may be edge-lit or may have internal openings that define the interior edges of the light guides. The illumination systems or devices 808 and 806, as detailed above, may be inserted into the internal openings of the one or more light guides to inject light into the interior edges (internal aperture light guides) or exterior edges (edge-lit light guides) of the one or more light guides. In embodiments, the one or more light guides may shape the light emitted by the illumination systems or devices 808 and 806 in a desired manner, such as, for example, a gradient, a beveled distribution, a narrow distribution, a wide distribution, or an angular distribution.

[0063] Application platform 802 may provide power and / or data to lighting systems or devices 806 and / or 808 via lines 804, which may include one or more or portions of power lines 702 and data bus 704 of Figure 7. One or more sensors (either sensors within vehicle headlamp system 700 or other additional sensors) may be internal or external to the housing of application platform 802. Alternatively or additionally, as shown in example vehicle headlamp system 700 of Figure 7, each of lighting systems or devices 808 and 806 may include its own sensor module, connection and control module, power supply module, and / or LED array.

[0064] In an embodiment, vehicle headlamp system 800 may represent a vehicle with a steerable light beam in which LEDs may be selectively activated to provide steerable light. For example, an array of LEDs or emitters may be used to define or project a shape or pattern, or to illuminate only selected portions of a road. In an example embodiment, the infrared camera or detector pixels in lighting systems or devices 806 and 808 may be sensors (e.g., similar to the sensors of sensor module 710 of FIG. 7) that identify portions of a scene (e.g., a road or crosswalk) that require illumination.

[0065] While embodiments have been described in detail, those skilled in the art will appreciate, given this description, that modifications may be made to the embodiments described herein without departing from the spirit of the inventive concept. Accordingly, it is not intended that the scope of the present invention be limited to the specific embodiments illustrated and described.

Claims

1. at least one light guide including a cavity having a central portion, the at least one light guide being a parabolic collimator having a focus coincident with the central portion of the cavity and comprising a flexible material; an encapsulant material including at least one opening through which light is emitted; at least one light emitting element embedded in a cavity of the light guide at a focal point of the light guide, the light emitting element including a coating oriented toward the at least one opening in the encapsulant; A lighting device comprising:

2. 2. The lighting device of claim 1, wherein the parabolic collimator has a flat surface opposite the parabolic cross section of the parabolic collimator, and light emitted by the at least one light-emitting element is guided toward the flat surface by the at least one light guide.

3. 10. The lighting device of claim 1, wherein the cavity is elongated and extends along a length of the at least one light guide.

4. 4. The lighting device of claim 3, wherein the at least one light emitting element embedded in the at least one light guide is surrounded by the at least one light guide, leaving an air gap between the at least one light emitting element and the at least one light guide.

5. 10. The lighting device of claim 1, wherein the at least one light guide further comprises at least one fastening element configured to mechanically fasten the at least one light guide to the encapsulant material.

6. The lighting device of claim 1 , wherein the at least one light emitting element is on a flex foil.

7. The lighting device according to claim 6 , wherein the at least one light-emitting element comprises a plurality of light-emitting elements arranged along a longitudinal direction of the lighting device.

8. 8. The lighting device of claim 7, wherein the flex foil is at least partially coated with a coating that defines at least one wavelength to which light emitted by the at least one light emitting element is converted.

9. 10. The lighting device of claim 8, wherein the flex foil and the coating form a hemispherical shape, and the flex foil together with the coating is at least partially embedded in the encapsulant material and at least partially embedded in the at least one light guide.

10. 10. The lighting device of claim 1, wherein the encapsulant surrounds the at least one light guide on three sides such that light emitted by the at least one light emitting element is blocked by the encapsulant.

11. 11. The lighting device of claim 10, wherein the encapsulant is configured to reflect light emerging from the at least one light guide towards the encapsulant covering at least a portion of the light guide.

12. A method for manufacturing a lighting device, comprising: providing at least one light guide including a cavity having a central portion, the at least one light guide being a parabolic collimator having a focus coincident with the central portion of the cavity and including a flexible material; providing an encapsulant including at least one opening through which light is emitted; providing at least one light emitting element; embedding the at least one light emitting element in a cavity of the light guide at a focal point of the light guide, the light emitting element including a coating oriented toward the at least one opening of the encapsulant; A method comprising:

13. 1. A lighting system for an automobile, comprising: at least one lighting device, at least one light guide including a cavity having a central portion, the at least one light guide being a parabolic collimator having a focus coincident with the central portion of the cavity and comprising a flexible material; an encapsulant material including at least one opening through which light is emitted; at least one light emitting element embedded in a cavity of the light guide at a focal point of the light guide, the light emitting element including a coating oriented toward the at least one opening in the encapsulant; at least one lighting device comprising: at least one light emitting element driver configured to provide a drive current to the at least one lighting device; a controller configured to receive at least one signal and turn on and off the at least one light-emitting element according to the received at least one signal; 1. A lighting system for an automobile, comprising:

14. 14. The automotive lighting system according to claim 13, wherein the automotive lighting system is one of a headlight, a backlight, an interior light, or a body light included in a body of a vehicle.

Images