Bendable lighting device

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 with an elongated recess. A plurality of light-emitting elements are embedded in the recess of the light guide, disposed on a flex foil that is bendable in three different directions, and connected to each other to mimic a filament. At least one encapsulating material at least partially encapsulates the at least one light guide. The at least one encapsulating material includes at least one opening and at least one reference element for aligning the at least one light guide with the encapsulating material so that the plurality of light-emitting elements emit light from the opening. The at least one encapsulating material is flexible such that the lighting device is bendable in three different directions.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 034,188, filed June 3, 2020, and European Patent Application No. 20188390.7, filed July 29, 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 is also used to electrically connect the light emitting elements. For example, the light emitting elements may be disposed on a printed circuit board (PCB) that includes conductive tracks for supplying electrical energy to the light emitting elements. However, substrates such as PCBs may limit the shape of the lighting device, such as to an essentially flat shape for simple substrates. Summary of the Invention

[0003] 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 with an elongated recess. A plurality of light-emitting elements are embedded in the recess of the light guide, disposed on a flexfoil that is bendable in three different directions, and connected to each other to mimic a filament. At least one encapsulating material at least partially encapsulates the at least one light guide. The at least one encapsulating material includes at least one opening and at least one reference element for aligning the at least one light guide with the encapsulating material so that the plurality of light-emitting elements emit light out of the opening. The at least one encapsulating material is flexible so that the lighting device is bendable in three different directions. [Brief explanation of the drawings]

[0004] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which:

[0005] [Figure 1] FIG. 1 is a schematic diagram of an exemplary lighting device in perspective view.

[0006] [Figure 2a] FIG. 1 is a schematic diagram of a flex foil filament in a top view and a flex foil with a hemispherical light emission.

[0007] [Figure 2b] 2b is a schematic diagram of a flex foil filament in side view (FIG. 2b) and a flex foil with hemispherical light emission.

[0008] [Figure 3a] FIG. 1 is an exploded view of an embodiment of a lighting device.

[0009] [Figure 3b] 3b is a cross-sectional view of the lighting device of FIG. 3a.

[0010] [Figure 4] 1 is a schematic diagram of another embodiment of a lighting device in a perspective view.

[0011] [Figure 5] 1A and 1B are perspective views of a lighting device bent in three different directions.

[0012] [Figure 6] FIG. 1 is a flow diagram of an exemplary method for manufacturing a lighting device.

[0013] [Figure 7] FIG. 1 is a diagram of an exemplary vehicle headlamp system that may incorporate one or more of the embodiments and examples described herein.

[0014] [Figure 8]FIG. 2 is a diagram of another exemplary vehicle headlamp system. DETAILED DESCRIPTION OF THE INVENTION

[0015] 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 can 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 disclosure in any manner. Like numbers refer to like elements throughout.

[0016] In this specification, terms such as first, second, and third may be used to describe various elements, but it is understood that 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 termed a second element, and a second element may be termed 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.

[0017] When an element, such as a layer, region, or substrate, is referred to as being "on" or extending "on" another element, it is understood that it is directly on or extending directly onto 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 onto" another element, there may be no intervening elements present. Also, when an element is referred to as being "connected" or "coupled" to another element, it is understood that the element may be directly connected or coupled to the other element and / or connected or coupled to the other element via one or more intervening elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements between the element and the other element. It is understood that these terms are intended to encompass different orientations of the elements in addition to the orientation depicted in the figures.

[0018] Relative terms such as "below," "above," "upper," "below," "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 is understood that these terms are intended to encompass different orientations of the device in addition to the orientation shown in the figures.

[0019] In many applications, it may be desirable to provide a lighting device that can be made into various shapes, e.g., has flexible properties. Flexible lighting devices can be used to conform to the shape of an object. For example, in automotive applications, flexible lighting devices can follow the surfaces or lines of the body or of interior elements such as panels or dashboards. Similarly, flexible lighting devices can be used in architecture or interior decoration and can be easily integrated into the structure.

[0020] In automotive lighting applications, it may be desirable to provide styling for the signaling function of the lamp, either for rear signaling functions such as turn signals, position lights, stop lights, or brake lights, as well as for forward signaling functions such as position lights or day running lights (DRLs), to name a few. These signaling applications are often designed as line emitters for automotive lamps.

[0021] Additionally, automotive applications requiring light styling are moving into the grille, outside the headlamp, and even into the interior of the car. Products that offer greater freedom in styling line sources, such as bi-axial bendable line emitters, can meet some of these styling requirements.

[0022] Current so-called 3D LED architectures can meet the specifications for automotive signaling applications, but due to the complexity of their systems, they can have a high bill of materials, such as silicone, wiring, and boards. In addition, the module construction and assembly process can be relatively complicated, especially the placement of wire frames and boards. Furthermore, thermomechanical stresses can pose challenges to robustness over their lifetime, especially when the system is molded and assembled into fixtures.

[0023] The embodiments described herein may provide lighting devices and corresponding methods of manufacture for automotive applications and the like that may provide desired 3D shapes while simplifying the bill of materials, simplifying the construction and assembly process, and reducing thermomechanical stresses.

[0024] FIG. 1 is a schematic diagram of an exemplary lighting device 2 in a perspective view. In some embodiments, the lighting device may represent, for example, an optical system. In the example shown in FIG. 1, the lighting device 2 has a front end portion, a flex foil filament 16, a back end portion, a light guide 4, and an encapsulation material 10 for the flex foil filament 16. The arrows shown between the assembled lighting device 2 and the front end portion and the back end portion indicate that the lighting device 2 can be manufactured by combining the flex foil filament 16 with the encapsulation material 10. In an embodiment, the flex foil may enable the lighting device to be bendable in three directions, e.g., X, Y, and Z.

[0025] As used herein, a flex foil may refer to a flexible strip that may include several conductor tracks provided by the flexible strip. The conductor tracks may connect one or more light-emitting elements to one another. Furthermore, a power source 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 light-emitting elements can be placed.

[0026] The flex foil may be elongated so that multiple (e.g., at least two) light-emitting elements can be arranged on the flex foil. The light-emitting elements may mimic filaments. The flex foil may have or be made of, to give one non-limiting example, a polyimide foil with leads. The leads may represent conductor tracks for connecting one or more light-emitting elements arranged on the flex foil. The flex foil may be very thin, such as between 20 μm and 40 μm thick.

[0027] Such flex foils are compact. Furthermore, they may enable narrower light-emitting areas, which may be beneficial for optical design in general and optical integration in particular. The width of such flex foils may enable slim, low-energy architectures (LEAs) of 2 mm or less, which may be beneficial for optical design.

[0028] In the example shown in FIG. 1 , the encapsulating material has an opening 14 covered by an optical element, in the example shown, a diffuser 20. Light emitted by the light-emitting element, which may be a mini-LED, of the flex foil filament 16 can be emitted toward the opening 14 and diffused by the optical element 20. The light guide 4 can have an elongated recess 6 (not shown in FIG. 1 ). Furthermore, the encapsulating material 10 can have a reference element 12, the height of which can extend into the encapsulating material 10 and to its bottom side. The reference element 12 can be for aligning the light guide 4 with the encapsulating material 10 when the flex foil filament 16 is embedded (e.g., inserted) into the light guide 4. The light guide 4 can be embedded (e.g., inserted) into the encapsulating material 10. The light guide 4 can have a recess 6 that matches the reference element 12 of the encapsulating material 10. When the light emitting element 8 of the flex foil filament 16 is driven by a power source, light may be emitted in such a way that it exits the opening 14 in the encapsulant 10. In the example shown, the light is also diffused by the diffuser 20.

[0029] A light guide may also be referred to as a mix box. At least one light guide may be optically coupled to a light-emitting element. Such a light guide may, for example, transmit light over a specified distance to a light-emitting surface via a specific path with minimal losses. Therefore, the radiation characteristics of the light emitted from the light guide may be precisely controlled, for example, to meet legal requirements. To this end, the appropriate transmittance and / or reflectance of the light guide's surface may be adjusted. The light guide may be manufactured from any suitable optically transparent material and may include a recess in which the light-emitting element can be embedded. If the light-emitting element is disposed on a flex foil, the flex foil may be embedded in the recess. The flex foil may be a carrier for the light-emitting element. In this way, the light emitted by the light-emitting element may be guided in one or more directions by the light guide. For example, the light guide may mix the light emitted by the light-emitting element so that the light is evenly distributed in a certain direction.

[0030] According to exemplary embodiments of the present invention, the encapsulating material may be or may include silicone. The encapsulating material may be flexible. Being flexible allows the lighting device and components therein to be bent in up to three different directions, for example, simultaneously. This may allow the lighting device to be formed to correspond to a required shape, such as predefined by an automobile headlamp or backup lamp and / or a particular interior or exterior body portion of a vehicle, to name a few non-limiting examples. The encapsulating material may surround a flex foil.

[0031] Thus, the lighting devices described herein may enable bendable lighting devices, for example, by using ultra-compact flex foils with high integration of light-emitting elements, such as mini-LEDs or dies, which can be assembled to represent elongated optical systems. Such optical systems may add mechanical interfaces that may enable easier integration due to defined interfaces provided by back-end systems represented by encapsulation materials that can hold additional features for optical and mechanical references and fixation, to name a few non-limiting examples. For example, such optical and mechanical references and fixation may enable the lighting device to be attached to interior elements, body parts, or vehicle headlights or taillights.

[0032] According to some embodiments, the at least one reference element may be an elongated height extending along the opening in the longitudinal direction of the lighting device. This may allow the encapsulation material to be configured essentially endlessly or one-dimensionally as a semi-finished product. Thus, the heights may be stably positioned throughout the encapsulation material. The heights may be shaped to allow engagement with the light guide so that when the encapsulation material and the light guide are assembled, both are referenced to each other in a predefined manner.

[0033] According to some embodiments, the at least one reference element may further enable sealing of the at least one light guide with the sealing material. Thus, the lighting device may have a certain waterproof function. Furthermore, this may also reduce thermomechanical stresses, especially when the flex foil filament or the flex foil with a hemispherical light emission is attached to the exterior of the vehicle, since the lighting device may typically expand and contract during temperature changes, at least if the sealing material is silicone-based. Sealing the lighting device may prevent temperature changes from affecting the performance of the lighting device.

[0034] 2a and 2b are schematic representations of a flex foil filament and a flex foil with hemispherical light emission in a top view (FIG. 2a) and a side view (FIG. 2b), respectively. FIG. 2a shows a flex foil 16 coated with a phosphor coating 18. The flex foil 16 may be in the form of a flex foil strip. A plurality of light-emitting elements 8 may be disposed on the flex foil strip and connected by conductive tracks 24. The phosphor coating 18 may be applied (e.g., molded or dispensed) to the top surface of the flex foil strip. This may enable hemispherical light emission when power is applied to the plurality of light-emitting elements 8. A power source (not shown in FIGS. 2a and 2b) may be connected via the conductive tracks 24. Light does not have to be emitted on the bottom side. To enhance light blocking, an additional coating that blocks light emitted from the bottom side may optionally be applied to the flex foil strip.

[0035] In the example shown in FIG. 2b, the flex foil 16 is coated on both sides with a phosphor coating 18. This is indicated by the phosphor coating 18 being marked with two reference symbols corresponding to FIG. 2b. Multiple light-emitting elements 8 may be arranged on the flex foil strip of FIG. 2b according to the flex foil 16 of FIG. 2a. The multiple light-emitting elements 8 may be connected by conductive tracks 24. Covering the flex foil strip on both sides, for example with a phosphor coating 18, may enable omnidirectional light emission when multiple light-emitting elements 8 are driven. Thus, the flex foil strip of FIG. 2b may emit light on all sides, and the light may be evenly distributed. While a phosphor coating has been described above, it will be understood that other coatings of the flex foil strip are possible to adapt the flex foil strip to specific optical requirements and / or applications.

[0036] The light-emitting element, and optionally other components such as a flex foil and coatings on the flex foil covering the light-emitting element, may represent the front-end portion of the lighting device. By having deeper system integration of the front-end portion, for example, where LEDs (L0, die level) are integrated or placed directly on the flex foil carrier, miniaturization with significant cost benefits during manufacturing can be achieved while maintaining the key advantages of 3D bendable optical systems such as the 3D LED system described above. The key advantages may be considered to be the compactness of the lighting device and the high uniformity of the light emitted by the lighting device, regardless of the shape into which the lighting device is bent. Some compromises may be made regarding the flexibility and / or bendability of the lighting device, which may decrease, and the luminous flux may also decrease due to the use of at least one light-emitting element embedded in the flex foil and light guide. However, the applications described herein may easily tolerate these minor compromises.

[0037] 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 at least partially arranged along the longitudinal direction relative to one another. The light-emitting elements may be spaced along the longitudinal direction, for example, at regular or irregular intervals. For example, the lighting device may have substantially the shape of a strip, for example, with a substantially constant cross-section. This arrangement of the light-emitting elements allows the lighting device to be constructed as a semi-finished product in an endless or one-dimensional manner, significantly reducing production costs and allowing the length of the lighting device to be selected after the semi-finished product is produced.

[0038] In some embodiments, the plurality of light emitting elements may be arranged at a density such that at least one light emitting element is arranged every 1 to 3 mm along the length of the flex foil. Alternatively, approximately 10 to 100 light emitting elements may be arranged per cm of the flex foil. 2 The light emitting elements may be arranged in a line. Additionally, the light emitting elements may be arranged across the width of the flex foil.

[0039] Arranging light-emitting elements at such a density allows for the use of compact light-emitting elements (e.g., mini-LED dies) and low currents to power the light-emitting elements. This may enable the use of small conductor tracks as small as 20 to 40 microns. Because less space is required for routing the conductor tracks, the flex foil may facilitate a larger number of conductor tracks. Even the overall width of the flex foil may be limited to 1.5 mm or less. A larger amount of routing conductor tracks distributed across the width of the flex foil may provide a larger number of addressable segments of light-emitting elements when such dynamic control of light-emitting elements at least partially isolated from one another is desired or required by the specifications of a particular lighting fixture.

[0040] Furthermore, having a very high density of LEDs in the 1 to 3 mm pitch range, combined with the aforementioned mini LED die (low power), and having a size of 0.1 x 0.5 mm or less along the length of the flex foil, can facilitate achieving high uniformity of emitted light in a smaller volume. This can negate the need for a dedicated diffuser. Additionally, this can reduce the size of the lighting device, thereby increasing its appeal in some automotive applications (e.g., rear, position, and body lighting). The elimination of the dedicated diffuser can facilitate optical integration of the lighting device into one or more other elements (e.g., body or automotive lamps) because the lighting device used as a light source can be smaller and provide uniform light emission. The étendue can also be smaller, resulting in its use in collimated optics, to name one non-limiting example. Furthermore, its potentially improved compactness can also reduce bill of materials (BOM) costs.

[0041] A large number of light-emitting elements (e.g., mini LED dies) can facilitate heat distribution across the surface of the line emitter, especially when the silicone is made up of at least an encapsulant, due to the silicone's poor thermal conductance. Using low power (e.g., 10 mA, 2.68 V for blue mini LED dies) can limit the localized heat generated by the light-emitting elements.

[0042] The phosphor coating may act as a wavelength converter, allowing for example the frequency of visible light to be changed. It will be appreciated that in addition to or as an alternative to a phosphor coating, respective coatings may be used that block light in specific directions and / or define the specific wavelength and / or intensity to which the emitted light is converted.

[0043] To control the color or distribution of the emitted light, phosphors in silicone or metal oxides in silicone (e.g., TiO2) can be applied to the light-emitting elements on the flex foil as a coating for optical functionality. The coating (e.g., phosphors in silicone or metal oxides in silicone) can be placed on one or both sides of the flex foil. This can be done on one side, providing a source with hemispherical light emission. If a transparent or translucent flex foil is used and the phosphors in silicone or metal oxides in silicone are applied to both sides, an omnidirectionally emitting flex foil filament can be achieved. Thus, if the flex foil has at least one light-emitting element placed 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 placed on one side of the flex foil, the light emission can be omnidirectional because it can transmit through the transparent flex foil. As used herein, a flex foil and at least one light emitting element that provides omnidirectional emission of light may also be referred to as a flex foil filament. Such kind of flex foil filaments are typically applied in retrofit light bulbs.

[0044] Alternatively, a flex foil and at least one light-emitting element that provides hemispherical light emission may be referred to as a flex foil with hemispherical light emission. Such a flex foil with hemispherical light emission may emit light on one side of the flex foil. Therefore, such a flex foil with hemispherical light emission may have a blocking layer on the other side, or may be opaque (e.g., a solid layer) or non-transparent so that light emission can be directed to one side of the flex foil. The blocking layer or solid layer may ideally be reflective for efficiency reasons. In this way, as little light as possible is lost, and at least a portion of the reflected light can be emitted in the desired direction.

[0045] In some embodiments, the phosphor coating covers both sides of the flex foil, and at least one light-emitting element can be located on both sides of the flex foil. In the case of multiple light-emitting elements, at least one light-emitting element can be located on one side and at least one additional light-emitting element can be located on the opposite side of the flex foil. Such a flex foil filament or flex foil with hemispherical light emission can be embedded in a recess in the light guide, such as by inserting the flex foil filament or flex foil with hemispherical light emission into the recess. The recess can be shaped to correspond to the cross-sectional diameter of the flex foil filament or flex foil with hemispherical light emission, optionally with the coating. Alternatively, the recess can be shaped larger than the cross-sectional diameter of the flex foil filament or flex foil with hemispherical light emission, so that an air chamber can be provided surrounding the flex foil filament or flex foil with hemispherical light emission.

[0046] The compactness of the flex foil or flex foil filament with hemispherical light emission allows the flex foil or flex foil filament with hemispherical light emission or light emitting element to be located within an air chamber, thereby reducing thermomechanical stresses due to torsion and power supply of the light emitting element. This may allow the lighting device to complement the thermomechanical isolation between the light emitting element or flex foil filament or flex foil with hemispherical light emission and the light guide and / or encapsulation material that represent the back end of the optical system. The air chamber may have optical advantages because a high refractive index contrast is often desired for good optical performance, and the air gap allows the highest possible contrast (e.g., air to silicone = 1:~1.4) to be achieved.

[0047] In some embodiments, twisting of the lighting device can be optically compensated for by light being emitted equally in all directions of the flex foil. By integrating and / or embedding an omnidirectionally emitting flex foil filament, twisting of the lighting device can be optically compensated for by light emission that can be equal in all directions of the flex foil. Therefore, twisting of the lighting device, and therefore bending, in any or all of the three different directions can be optically insignificant. Also, because emitted light can escape directly to the bottom of the encapsulation material, high reflective properties of the encapsulation material may be required. For example, the encapsulation material may have a reflectivity of at least 95% or more to achieve the efficiency of an appropriate encapsulation material (e.g., a mixbox). Highly reflective silicone materials may be used, which may be loaded with metal oxides such as TiO. The loading of these materials can range from 5 to 30% by weight. Too high a particle loading can reduce the flexibility of the silicone and even make it brittle.

[0048] For example, integrating the flex foil in-plane with one of the axes of each of the three bending directions (e.g., the longitudinal direction of the lighting device, e.g., the Y-axis) can allow twisting in the bending region of the flex foil. This means that in the case of twisting, the light emitting elements may locally rotate in a different direction than light emitting elements arranged in a straight region of the flex foil. However, due to its compactness and the embedding of the flex foil in the light guide and encapsulant, twisting of the flex foil can cause light directed more to the sides to mix and escape from the light-emitting region of the encapsulant. This assumes that a flex foil with a hemispherical light emission is assembled into the encapsulant. This means that the flex foil can be attached so that light is directed to the light-emitting region defined by the opening in the encapsulant.

[0049] According to some embodiments, the at least one light-emitting element may be at least partially in contact with the recess of the at least one light guide. Alternatively, the light-emitting element or the flex foil filament or the flex foil with the hemispherical light emission may be in direct contact with the light guide and / or the encapsulant, as opposed to an air chamber. While thermomechanical stresses may be higher compared to the use of the air chambers disclosed above, this may allow the lighting device to be more tolerant to twisting.

[0050] FIG. 3a is an exploded view of one embodiment of a lighting device. In the example shown in FIG. 3a, the lighting device 2 may have a light guide 4 with an embedded flex foil filament 16. The lighting device 2 may also have an encapsulation material 10 with a reference element 12 that may be configured to receive the light guide 4 with the embedded flex foil filament 16. Above the light guide 4, the lighting device 2 may have an optical element 20, in the illustrated example, a diffuser. All of the aforementioned components can be assembled together to form the lighting device 2. Adding a simple diffuser, such as in the form of a layer, can create an off-state white (or other color) appearance as specified by the optical element. Thus, the lighting device can be adapted to specific applications / customers as needed.

[0051] Figure 3b is a cross-sectional view of the lighting device of Figure 3a, showing how all of the aforementioned components are assembled together to form lighting device 2.

[0052] FIG. 4 is a schematic diagram of another embodiment of a lighting device in a perspective view. In the example of FIG. 4, the light guide 4 has a different shape than the light guides shown in the previous examples. Furthermore, in contrast to the exemplary embodiments of lighting devices shown in the previous figures, the illustrated lighting device 2 of FIG. 4 is not attached to an optical element, such as an automotive lamp, to give one non-limiting example. In the example shown in FIG. 4, the light guide 4 is shaped so that light emitted by the light-emitting element, which is disposed on the flex foil and thus represents the flex foil filament 16, is guided in one or more specific directions. Furthermore, the light guide 4 may allow for adapting the intensity at which the light is emitted. The reference elements 12 and respective recesses of the light guide 4 for enabling alignment of the light guide 4 relative to the encapsulation material 10 may correspond to the respective elements of the exemplary embodiments shown in the previous figures.

[0053] FIG. 5 is a perspective view of a lighting device bent in three different directions. In the example of FIG. 5, three axes—X-axis D1, Y-axis D2, and Z-axis D3—are shown. The Y-axis corresponds to the longitudinal direction of the lighting device 2. Therefore, the Y-axis extends to the bottom of the illustration of the lighting device 2. The top of the lighting device 2 may be higher than the bottom. The lighting device 2 may be bent in all three directions shown from the top to the bottom. From the top, it may first bend downward to its left. It may then bend further downward and turn approximately 90° to the right. Ending at the bottom, the lighting device 2 lies flat on its lower surface and then turns approximately 90° to the left. Thus, the lighting device 2, and at least the encapsulating material 10 of the lighting device 2, may be flexible so that the lighting device 2 may be bent. For example, in FIG. 5, the lighting device 2 is bent in three different directions, as indicated by reference characters D1, D2, and D3.

[0054] As shown in Figure 5, when the light emitting elements 8 of the flex foil 16 are driven, for example, the integration of a dedicated LED as one of the light emitting elements with a wire level 2 (L2) solution represented by the conductive track 24 enables a highly flexible lighting device 2 with high luminous flux, uniformity and compactness.

[0055] This described flex foil filament or flex foil with hemispherical light emission front-end technology can be combined with an additional optical system. This can be, for example, a silicone-based elongated light guide (e.g., a mix box) that encapsulates the flex foil filament or flex foil with hemispherical light emission. Additionally, a dedicated diffuser can be included to provide uniform brightness from the light-emitting area. Such an assembly can result in an elongated LED module that can be mounted, for example, in a car lamp, but also in the car body or interior elements due to its flexibility.

[0056] For applications with looser specifications regarding luminous flux and bending parameters, alternatives to flex foil filaments or flex foils with hemispherical light emission can be considered, based on the principle of embedding a thin carrier containing at least one light-emitting element and which can be covered with a coating and encapsulation material within a light guide to reduce costs. Furthermore, the use of flex foil filaments or flex foils with hemispherical light emission can reduce the assembly complexity of such elongated (e.g., 3D LED) lighting devices through a simpler assembly process. Furthermore, addressing some of the light-emitting elements on the flex foil by utilizing conductive tracks can realize, for example, bicolor or multicolor flex foil filaments or flex foils with hemispherical light emission. Light-emitting elements emitting light of different wavelengths can be arranged on the flex foil. Furthermore, they may need to be wired in a way that allows them to be driven separately.

[0057] In some cases, bidirectional or omnidirectional light emission may be preferred (e.g., as part of a surface emitter), which can be achieved by a specific coating applied to the flex foil.

[0058] For example, simple optical integration of the lighting device into car lamps (front lights or back lights), interior elements (e.g., doors or dashboards), and / or body elements (e.g., grilles and wheel housings) may be enabled. Also, the lighting device according to the first aspect may be scaled up so that larger light sources may be enabled. This may also increase the possibilities for optical design, such as in the light path. This may also be preferable for meeting certain defined design criteria and / or requirements (e.g., standards to be met).

[0059] 1 and 3a can be seen to illustrate how a bendable, elongated module of a lighting device can be manufactured by using a flex foil filament 16. The flex foil filament 16 is made of flex foil (e.g., polyimide-based) with electrode (conductive) tracks 24 laid out to address an array of mini LEDs 8 (e.g., flip chips). These mini LEDs 8 can be blue emitters and can be densely arranged (high density arranged on the flex foil strip). Depending on the application, LED emitters of other colors can also be used.

[0060] The blue mini-LEDs 8 are covered with a phosphor mold 18, which can convert the blue light to white (or alternatively, to another color, if desired, enabled by a separate coating). On the other side of the flex foil, there may also be a phosphor mold 18, which allows the blue light to pass through the transparent flex foil to the bottom surface. The phosphor concentrations of the phosphor coatings 18 on the top and bottom surfaces can be adjusted relative to one another to achieve the correct color behavior over angles. Furthermore, the phosphor coating 18 can have scattering properties. In combination with a high density of mini-LEDs 8, this can result in the appearance of a very uniform brightness of the flex foil filament 16. If other colors are to be emitted, phosphor need not be used; instead, bare silicone or silicone with certain diffusing and colored properties can be applied as the respective coating.

[0061] Figure 6 is a flow diagram of an exemplary method for manufacturing a lighting device. In the example shown in Figure 6, the method includes providing a light guide with an elongated recess (602). A plurality of light emitting elements may be provided (604). The plurality of light emitting elements may be disposed on a flex foil (606). The flex foil may be bendable in three different directions. The plurality of light emitting elements may be connected to one another to mimic a filament (608). The light emitting elements may be embedded in the recess of the light guide (610).

[0062] An encapsulating material may be provided (612). The at least one light guide may be at least partially encapsulated with the encapsulating material (614). The encapsulating material may include at least one opening for light emission. The encapsulating may also include aligning the at least one light guide with the encapsulating material such that the plurality of light emitting elements emit light exiting the opening by at least one reference element engaging an elongated recess in the light guide. An illumination device may be provided (616). The illumination device may be configured as an endless semi-finished product having a length to be selected after manufacture.

[0063] In some embodiments, the flex foil can be embedded in a sealing material such as silicone with an air chamber (e.g., an air gap) established between the light guide and the flex foil filament or flex foil with hemispherical light emission when the flex foil filament or flex foil with hemispherical light emission is embedded in the light guide. In some embodiments, the embedding can include extruding a white box or white mixed box as the light guide with a recess (e.g., 1K extrusion). A sealing material (e.g., air tube) can be extruded (e.g., 1K extrusion). A front-end flex foil assembly can be inserted into the light guide. The lengths of the light guide and flex foil can correspond to each other.

[0064] The light guide can be glued to the white box and optionally cured. The gluing process can be controlled to prevent excess glue from entering the air chamber. The light guide can be embedded with a flex foil filament, or a flex foil with a hemispherical light emission can be sealed with a sealing material. Optionally, a diffuser can be attached or dispensed on top of the light guide. The diffuser can be cured to secure it in place.

[0065] The assembly steps described in the above paragraphs may be simplified, and the order of process steps may differ from these examples. In some embodiments, for example, a white box may be extruded using a 2K process, using white for the mix box and clear silicone for the light-emitting area. This extrusion process can be extended to integrate additional optical components, such as collimators, as their respective optical elements.

[0066] Alternatively, the flex foil may be embedded in an encapsulation material (e.g., silicone) without an air interface between the flex foil filament or the flex foil with hemispherical light emission and the encapsulation material. In such an embodiment, a white box or a mixed box may be extruded (e.g., 1K extrusion) as a light guide. A front-end flex foil assembly with one or more light-emitting elements may be embedded (e.g., inserted) into the white box. The white box may be filled with transparent silicone that fixes the flex foil with hemispherical light emission or the flex foil filament inside the optical system. The light guide embedded in the flex foil filament may be sealed with an encapsulation material. Optionally, a diffuser may be attached or dispensed on top of the light guide in which the flex foil filament or the flex foil with hemispherical light emission is embedded (e.g., inserted). It may then be cured for fixation.

[0067] 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.

[0068] The power line 702 may have an input for receiving power from the vehicle, and the data bus 704 may have an input and output 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 from elsewhere in the vehicle, such as instructions to turn on turn signaling or turn on headlamps, and may transmit feedback to other locations in the vehicle as needed. A sensor module 710 may be communicatively coupled to the data bus 704 and may provide additional data to the vehicle headlamp system 700 or elsewhere in the vehicle, for example, regarding 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 the 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.

[0069] An input filter and protection module 706 may be 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 706 may provide electrostatic discharge (ESD) protection, load dump protection, alternator field decay protection, and / or reverse polarity protection.

[0070] 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 that powers the LEDs in the lighting device of the active headlamp 718. The LED DC / DC module 712 may have an input voltage of between 7 and 18 volts, with a nominal voltage of approximately 13.2 volts, and an output voltage slightly higher (e.g., 0.3 volts) than the maximum voltage of the light emitting elements of the lighting device (e.g., determined by coefficients or local calibration and adjustments for operating conditions due to load, temperature, or other factors).

[0071] 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 the active headlamp 718, such as CMOS logic.

[0072] 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 include data from the sensor module 710. The converted vehicle inputs may include a video signal 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, as well as logic LDO outputs. In embodiments, the LED DC / DC output 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.

[0073] 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.

[0074] 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.

[0075] If included, the secondary optics 810 / 812 may be or include one or more light guides. The one or more light guides may be edge lit or may have an internal opening that defines the interior edge of the light guide. The illumination systems or devices 808 and 806 may be inserted into the internal opening of the one or more light guides to inject light into the interior edge (internal aperture light guide) or exterior edge (edge ​​lit light guide) of the one or more light guides, as described above. 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 chamfered distribution, a narrow distribution, a wide distribution, or an angular distribution.

[0076] 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 FIG. 7. One or more sensors (such as those in 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 FIG. 7, each lighting system or device 808 and 806 may include its own sensor module, connection and control module, power supply module, and / or LED array.

[0077] In an embodiment, vehicle headlamp system 800 may represent an automobile with a steerable light beam in which LEDs can 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 sections of a road. In one exemplary embodiment, an infrared camera or detector pixel in lighting systems or devices 806 and 808 may be a sensor (e.g., similar to the sensor in sensor module 710 of FIG. 7) that identifies portions of a scene (e.g., a road or crosswalk) that require illumination.

[0078] Although the embodiments have been described in detail, those skilled in the art will appreciate, upon consideration of 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 invention be limited to the specific embodiments illustrated and described.

Claims

1. 1. A lighting device comprising: at least one light guide having an elongated recess; a plurality of light emitting elements embedded in the elongated recess of the light guide, arranged on a flex foil that is bendable in three different directions, and connected to each other to mimic a filament; At least one encapsulating material at least partially encapsulating the at least one light guide: at least one opening; a reference element disposed at a position for aligning the at least one light guide with respect to the encapsulating material so that the plurality of light emitting elements emit light out of the opening; the at least one encapsulant is flexible so that the lighting device bends in the three different directions. at least one sealing material; the one reference element is an elongated high point extending along the opening in the longitudinal direction of the lighting device, and has a tapered shape protruding from an inner surface of the sealing material located on the opposite side of the opening in a cross section perpendicular to the longitudinal direction toward the opening; Lighting device.

2. the lighting device is configured as an endless semi-finished product having a length selected after manufacture; 10. The lighting device of claim 1.

3. The plurality of light-emitting elements are arranged along the longitudinal direction.

10. The lighting device of claim 1.

4. The plurality of light emitting elements are arranged at a density of at least one light emitting element arranged every 1 to 3 mm along the longitudinal direction.

4. A lighting device according to claim 3.

5. the flex foil is at least partially coated with a phosphor coating that defines at least one or more directions in which the plurality of light emitting elements emit light; 5. A lighting device according to claim 4.

6. the phosphor coating covers both sides of the flex foil, and the plurality of light emitting elements can be disposed on both sides of the flex foil.

6. A lighting device according to claim 5.

7. - twisting of the lighting device is optically compensated by light being emitted evenly in all directions of the flex foil; 3. A lighting device according to claim 2.

8. further comprising at least one optical element that allows diffusion of light emitted by the plurality of light emitting elements; 10. The lighting device of claim 1.

9. the plurality of light-emitting elements are embedded in the at least one light guide such that an air chamber exists between the recess and the plurality of light-emitting elements when the plurality of light-emitting elements are embedded in the at least one light guide; 10. The lighting device of claim 1.

10. the plurality of light emitting elements at least partially contact the recess of the at least one light guide; 10. The lighting device of claim 1.

11. The one reference element further enables sealing of the at least one light guide and the sealing material.

10. The lighting device of claim 1.

12. the sealing material is or comprises silicone; 10. The lighting device of claim 1.

13. 1. A method of manufacturing a lighting device, the method comprising: providing at least one light guide including an elongated recess; providing a plurality of light emitting elements; disposing the plurality of light emitting elements on a flex foil that is bendable in three different directions; connecting the plurality of light emitting elements together to mimic a filament; embedding the plurality of light emitting elements in the elongated recess of the light guide; providing at least one encapsulating material; at least partially sealing the at least one light guide with the at least one sealing material, the sealing material having at least one opening for emitting light, the sealing step including aligning the at least one light guide with the sealing material such that the plurality of light emitting elements emit light out of the opening by a reference element engaging the elongated recess of the light guide; providing the lighting device configured as an endless semi-finished product having a selected length after manufacture; the one reference element is an elongated high point extending along the opening in the longitudinal direction of the lighting device, and has a tapered shape protruding from an inner surface of the sealing material located on the opposite side of the opening in a cross section perpendicular to the longitudinal direction toward the opening; method.

14. 1. A lighting system for an automotive vehicle comprising: At least one lighting device according to any one of claims 1 to 12; at least one light emitting element driver configured to provide a driving current to at least one of the lighting devices; and a controller configured to receive at least one signal and provide at least one control signal to the at least one light-emitting element driver to turn on and off at least one light-emitting element of the plurality of light-emitting elements according to the received at least one signal; Automotive lighting systems.

15. The automotive lighting system is one of a headlight, a backlight, an interior light, or a body light included in the body of the vehicle.

15. The automotive lighting system of claim 14.

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