Lighting device with flash effect

Abstract

The invention relates to a lighting device with a flash effect. A lighting apparatus includes: a solid state light emitting element mounted on a carrier substrate; a package including a light emitting material, the package surrounding a light emitting surface of the solid-state light emitting element, and configured to at least partially convert light emitted by the solid-state light emitting element into wavelength converted light; and a plurality of light transmissive particles at least partially contained within the package, the light transmissive particles having an average longest dimension extension in a range of 0.4 to 1.5 times a layer thickness of the package on the light emitting surface. The light-transmissive particles may interrupt the light-emitting effect of the package material to produce a flash effect.

Description

[0001] This application is a divisional application of the invention patent application with international application number PCT / EP2019 / 084338, international application date December 10, 2019, application number 201980082502.4 and invention name “Lighting device with flashing effect”, which entered the Chinese national phase on June 11, 2021. Technical Field

[0002] The present invention relates to a solid-state lighting device with a flashing effect and a method for manufacturing the solid-state lighting device. Background Art

[0003] Incandescent lamps are rapidly being replaced by solid-state light sources, such as lighting solutions based on light emitting diodes (LEDs). Despite this, users still appreciate and desire to have retrofit lamps with the appearance of incandescent bulbs. To this end, one can simply utilize the infrastructure for manufacturing glass-based incandescent lamps and replace the conventional filaments with LED filaments that emit white light. One of the concepts is based on LED filaments placed in such bulbs. The appearance of these lamps is highly appreciated as they look very decorative. Furthermore, it is desirable to introduce additional lighting effects to such decorative LED lighting devices. In particular, it is expected that the shimmering appearance of LED bulbs will be highly appreciated by the observers. That is, this effect is widely used in various industries to create a more attractive and stylish appearance.

[0004] Conventionally, efforts to produce such a sparkle effect in a lighting system have been directed to using a light source such as a conventional light bulb, an LED or a high power halogen bulb, and illuminating a surface provided with a layer of sparkle material, such as a layer of sparkle particles applied to a glass surface. Thus, a sparkle effect is achieved in the light reflected from the surface. In an alternative solution, such a light source is placed near a lead glass crystal. In this way, the system provides the effect without requiring separate mounting solutions for the light emitting source and the separate sparkle surface. However, these approaches have their attendant disadvantages and are generally costly and cumbersome to implement.

[0005] In an alternative solution disclosed in WO2017153252, a lighting device is proposed, which includes an exposed outer surface and at least one main light source arranged in a chamber. The chamber has an internal surface arrangement including a first surface portion and an opposite second surface portion. The main light source is located on the first surface portion. The second surface portion is translucent and the main light source illuminates a plurality of light exit areas defined by the translucent second surface, thereby providing two functional lightings for illuminating a space while having a spatial dynamic flash display.

[0006] Although this document discloses a more compact method, its solution follows the principle of having an illumination source and an incident panel. In addition, this method proposes a complex solution for creating a secondary light source with an anisotropic brightness emitting surface.

[0007]

[0006] Therefore, there is a need in the art to provide a more versatile, cost-effective, efficient and straightforward solution for lighting devices that deliver desired flash effects. Summary of the invention

[0008] It is therefore an object of the present invention to improve the prior art and to alleviate at least some of the above mentioned disadvantages.

[0009] These and other objects are achieved by providing a solid state lighting device with a flashing effect and a method of manufacturing a solid state lighting device with a flashing effect as defined in the appended claims.

[0010] According to a first aspect of the present invention, there is provided a lighting device providing a flashing visual effect, comprising: at least one solid-state light-emitting element mounted on a carrier substrate, the solid-state light-emitting element being configured to emit light from a light-emitting surface; a package comprising a light-emitting material, the package surrounding the (one or more) light-emitting surfaces of the at least one solid-state light-emitting element and being configured to at least partially convert the light emitted by the solid-state light-emitting element into wavelength-converted light; and a plurality of light-transmitting particles at least partially contained within the package, the light-transmitting particles having an average longest dimension extending in the range of 0.4 to 1.5 times the layer thickness of the package on the (one or more) light-emitting surfaces.

[0011] In the remainder of this description, the lighting device may sometimes be referred to as an "LED filament," but is not limited to this type of device.

[0012] An LED filament is understood to provide an LED filament lamp and comprises a plurality of light emitting diodes (LEDs) arranged in a linear array. Preferably, the LED filament has a length L and a width W, wherein L>5W. The LED filament may be arranged in a straight configuration or a non-straight configuration (such as, for example, a meander configuration, a 2D / 3D spiral or a helix). Preferably, the LEDs are arranged on an elongated carrier, such as a substrate, which may be rigid (made of, for example, a polymer, glass, quartz, metal or sapphire) or flexible (for example, made of a polymer or metal, such as a film or foil).

[0013] In case the carrier comprises a first major surface and an opposing second major surface, the LEDs are arranged on at least one of these surfaces.The carrier may be reflective or light transmissive (such as translucent), and is preferably transparent.

[0014] The LED filament may include an encapsulation that at least partially covers at least a portion of the plurality of LEDs. The encapsulation may also at least partially cover at least one of the first main surface or the second main surface. The encapsulation may be a polymer material, which may be flexible, such as silicone, for example. In addition, the LED may be arranged to emit, for example, LED light of different colors or spectra. The encapsulation may include a luminescent material that is configured to at least partially convert the LED light into converted light. The luminescent material may be a phosphor, such as an inorganic phosphor and / or quantum dots or rods. The LED filament may include a plurality of sub-filaments. "Light-transmitting" particles herein refer to particles that allow light to pass through and thus avoid the wavelength conversion effect of the light-emitting encapsulation. The particles may not emit light at all, or at least have a different luminescent effect than the encapsulation. They may also be color absorbers, thereby changing the color of the light. The particles may also cause a light scattering effect.

[0015] The light emitted by the solid state light emitting element may have a first spectral distribution. The wavelength converted light may have a second spectral distribution, and the first spectral distribution may be different from the second distribution.

[0016] The present invention is based on the recognition that such light-transmitting particles can be used to interrupt the luminescent effect of the package material. Thus, instead of a uniform wavelength conversion, some light from the light-emitting element will pass through the light-transmitting particles to avoid full wavelength conversion. In some embodiments, the particles are preferably transparent, which can provide a better flashing visual effect. The reason for this is that light is scattered less in transparent particles than in opaque or translucent particles.

[0017] The particles may be of varying sizes and geometries, but for the effect to be clearly visible, the size of the particles (defined here as "extending in the longest dimension") should be approximately the thickness of the package at the light emitting surface. Preferably, the average longest dimension extends 0.4-1.5 times the thickness.

[0018] The expression "longest dimensional extension" should be interpreted broadly and simply refers to the longest extension of a particle in any dimension. In other words, a particle will have different extensions (sizes) in different dimensions (directions), and "longest dimensional extension" refers to the largest of these. For symmetrical particles, the dimensional extension of the particle may be the same in all dimensions. For particles with asymmetric or arbitrary shapes, the particles may have varying dimensional extensions in different dimensions, where at least one dimensional extension may be the longest.

[0019] the term" average "Longest dimension extension" is used in order to account for the fact that in a sample with a plurality of particles of varying size and / or shape, the longest dimension extension of the particles may be different. Therefore, the average of all longest dimension extensions in the sample is used as the relevant measure.

[0020] In practice, it may be difficult to determine or establish the average longest dimension extension for a sample of particles. In some cases, another metric, such as a "D50" value, may be used as a relevant approximation. When the particles are conveniently modeled as spheres, the D value refers to the particle diameter, when all particles in the particle sample are arranged in ascending order of mass, dividing the mass of the sample into specified percentages. The mass percentage (wt%) below the diameter of interest is the number indicated after the "D". Specifically, D50 is a diameter at which approximately 50wt% of the mass of the particle sample has a diameter below the selected diameter. If the D50 value is within the relevant range, it can be assumed that the average longest dimension extension is also within the range.

[0021] In some embodiments, the particles may have a D50 in the range of 0.3 mm to 6 mm, or more preferably in the range of 0.4 mm to 4 mm, or most preferably in the range of 0.5 mm to 2 mm.

[0022] Additionally or alternatively, another metric may be used to select the desired size of the particles.For example, a sample of particles may be selected such that at least 50 wt% or at least 75 wt% or at least 85 wt% of the sample of particles will have a longest dimension extending within the relevant range.

[0023] The light emitted from the light emitting elements will pass through the package and the particles therein. Depending on the density of the particles, light from one light emitting element (in different directions) can hit several particles. In some embodiments, the density of the particles is such that light emitted from most light emitting elements (e.g., up to 90% of the light emitting elements) can hit at least two particles.

[0024] The present invention allows, for example, adding more decorative features (such as a glitter effect) to lighting devices having solid-state light-emitting elements arranged inside a bulb (e.g., an LED filament lamp), similar to the appearance of an incandescent bulb, thereby creating a more aesthetically pleasing appearance. These particles can have various geometric shapes and orientations and can be included in lighting devices with various manufacturing methods, which will be further discussed in the following invention summary and specific examples.

[0025] According to the present invention, one advantage of adding light-transmitting particles near the solid-state light-emitting element is that it reduces the complexity of additional manufacturing (such as the addition of an external patterned layer or grating) and provides a self-contained lighting device with a flashing effect. In addition, this method reduces the environmental footprint of each manufactured unit by reducing the amount of material per unit of the lighting device (such as plastic sheet parts, metal coatings, glass plates, etc.). This in turn reduces manufacturing complexity and cost per unit.

[0026] The larger the size of the light-transmitting particles, the less wavelength conversion provided by the package. In one example, the average longest dimension of the light-transmitting particles extends greater than 0.8 times the thickness of the layer of the package on (one or more) light-emitting surfaces, in which case the light emitted from the light-emitting surface may be little or not wavelength converted by the light-emitting package. In another example, the average longest dimension of the light-transmitting particles extends less than 0.8 times the thickness of the layer of the package on (one or more) light-emitting surfaces, in which case the light emitted from the light-emitting surface may still be more visibly wavelength converted by the light-emitting package.

[0027] For example, in the case of a blue LED, light-transmitting particles having a size extending between 0.8 and 1.2 times the package thickness can provide a blue flash. However, particles having a size in the range of 0.4 to 0.8 times the package thickness can provide a flash of color at the red wavelength end of the visible spectrum.

[0028] The particles may be symmetrical to ensure similar light conversion (or no conversion) regardless of the direction of the light. However, it is preferred that the light-transmitting particles have an asymmetrical shape to increase the irregularity of the glitter effect. For example, the particles may have an extension in the vertical direction that may be at least twice as large as the extension in the longitudinal and transverse directions.

[0029] In the context of the present invention, directions and orientations such as vertical, longitudinal and transverse need to be interpreted broadly and generally refer to the geometric extension of an object (e.g., a light-transmitting particle) in a coordinate system such as a three-dimensional Cartesian coordinate system. Thus, the spatial extension and unique position of each point of a light-transmitting particle can be defined in at least one plane of the coordinate system using a pair of numerical coordinates. Elongated (e.g., rice-shaped) particles are formed by extending the particle more (e.g., twice) in one of the three orthogonal directions (e.g., vertically more than longitudinally and transversely). Disc-shaped particles are formed by extending the particle more in two of the three orthogonal directions (e.g., vertically and longitudinally more than transversely).

[0030] According to a second aspect of the present invention, there is provided a method for manufacturing a light-emitting device providing a flashing visual effect, comprising: providing at least one solid-state light-emitting element mounted on a carrier substrate, each solid-state light-emitting element being configured to emit light from a light-emitting surface; providing a package comprising a light-emitting material, the package surrounding the light-emitting surface of at least one solid-state light-emitting element and being configured to at least partially convert the light emitted by the solid-state light-emitting element into wavelength-converted light; and providing a plurality of light-transmitting particles at least partially contained within the package, the light-transmitting particles having an average longest dimension extension in any dimension in the range of 0.4 to 1.5 times the layer thickness of the package on the light-emitting surface.

[0031] It should be emphasized that the steps of the second aspect may be performed in any logical order, for example providing a package surrounding the carrier substrate and the at least one solid state light emitting element before providing light transmissive particles near the at least one solid state light emitting element.

[0032] The effects and features of these first and second aspects of the present invention are largely similar, and the above-described embodiments are compatible with both aspects of the present invention.

[0033] According to an exemplary embodiment of the present invention, light-transmitting particles are mixed / dissolved into the encapsulant before the encapsulant is arranged on a carrier substrate.

[0034] The inventors have realized that easily mixing light-transmitting particles into the package has the advantage of facilitating the manufacturing process of the lighting device and reducing the manufacturing cost. In addition, using this process, the light-transmitting particles can be randomly distributed in the package to produce irregular visual effects.

[0035] According to another exemplary embodiment, the light-transmitting particles are deposited in a particle-retaining layer and the particle-retaining layer is arranged on a carrier substrate.The order of these steps may also be reversed.

[0036] The particle retaining layer may be applied / deposited on any other portion / side of the carrier substrate other than the light emitting elements. The particle retaining layer may be deposited in a continuous manner or in discontinuous portions in any desired layout, which may be advantageous in producing customizable flash effects. The light transmissive particles may be arbitrarily distributed in the particle retaining layer.

[0037] This method can result in a more effective flash effect due to a more controlled process in depositing the particle retaining layer relative to the LED elements. Although the particle retaining layer can be deposited anywhere on the substrate relative to the LED elements, the inventors have found that controlled deposition of the particle retaining layer in close proximity to the LED elements increases the efficiency of the LED filament in producing the flash effect. This class of lighting devices can be superior to the types previously explained where a higher quality and intensity of flash is desired and therefore a more complex and expensive manufacturing process is employed.

[0038] According to yet another exemplary embodiment, the light-transmitting particles may be deposited directly on the carrier substrate and / or the light-emitting elements. For example, the particles may be deposited on the substrate such that the particles only partially cover the LED elements and / or are located at a specific distance from the respective LEDs. The light-transmitting particles may also be deposited on either side of the carrier substrate in varying shapes and layouts.

[0039] The advantage of direct deposition is that the growth and deposition conditions of the light-transmitting particles can be precisely controlled, resulting in customizable flash effects from individual LEDs or from LED filaments. However, this category requires expensive manufacturing equipment and more complex manufacturing procedures.

[0040] According to a third aspect of the invention, there is provided a light bulb comprising a transparent shell, the light bulb comprising at least one of the lighting devices according to the first and second aspects of the invention, the lighting device being arranged within the shell and electrically connected to electrical contacts of the light bulb.

[0041] If the lighting device is an LED filament, the light bulb may be referred to as an LED filament lamp. The LED filament lamp may, for example, preferably include three to nine LED filaments or more preferably include four to six LED filaments.

[0042] The housing may be an envelope that substantially surrounds the lighting device. The light circuit also includes a base for connecting the lamp to a socket of the lamp fixture. The base is typically electrically connected to the lighting device.

[0043] Preferred features and advantages of the invention are as readily obtainable through this aspect of the invention as in the previously discussed aspects of the invention, and vice versa.

[0044] These and other features of the present invention will be further elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The above objects and other objects, features and advantages of the present invention will be more fully understood with reference to the following illustrative and non-limiting detailed description of embodiments of the present invention in conjunction with the accompanying drawings, in which:

[0046] Figure 1 A schematic cross-sectional top view of a lighting device according to at least one embodiment of the present invention is shown;

[0047] Figure 2a-2c shows a schematic cross-sectional side view of a lighting device according to at least one embodiment of the present invention;

[0048] Figure 3a-3c shows a schematic cross-sectional side view of a lighting device according to some exemplary embodiments of the present invention;

[0049] Figure 4 A light bulb is shown which includes Figure 1 The lighting equipment shown in .

[0050] As shown in the figures, some features (including particles, packaging, etc.) are or may be exaggerated for illustrative purposes, and are therefore provided to illustrate the general structure of an embodiment of the present invention. Like reference numerals refer to like elements throughout. DETAILED DESCRIPTION

[0051] In this detailed description, embodiments of the invention will be discussed in conjunction with the accompanying drawings. It should be noted that this in no way limits the scope of the invention, and the invention is also applicable in other cases, such as other types of methods or variations for manufacturing a lighting device with a flash effect, or other types of lighting devices or variations with flash effects different from the embodiments shown in the accompanying drawings. In addition, specific features mentioned in conjunction with embodiments of the invention do not mean that those components cannot be advantageously used with other embodiments of the invention.

[0052] The following description will use terms such as "top", "bottom", "inner", "outer", "side", etc. These terms generally refer to the views and orientations shown in the figures. These terms are used only for the convenience of the reader and should not be limiting.

[0053] The directions and extensions of the lighting device are discussed in more detail below using a coordinate system. Essentially, the vertical direction or z-direction is orthogonal or perpendicular to the carrier substrate. The longitudinal direction or y-direction is parallel to the longest extension of the lighting device. The transverse direction or x-direction is orthogonal to both the y-direction and the z-direction. The x-direction may be parallel to the longest extension of the solid-state light emitting element, but may also be a direction transverse to the longest extension of the solid-state light emitting element.

[0054] Figure 1 An example of a lighting device 1 is illustrated, which comprises a carrier substrate 2 and comprises at least one continuous portion 3 or discontinuous portion 4 of a solid-state light-emitting element arranged on top of the substrate 2. The light-emitting element is configured to emit light from a light-emitting surface. The carrier may be transparent to allow light from the light-emitting element to pass through it.

[0055] The solid-state light emitting element may be an LED, which has been widely used in a wide range of industries, such as lighting, automotive and aviation industries. Due to its low energy consumption, long life, compact size and fast switching characteristics, LED has attracted much attention in lighting solutions due to its arguably less negative environmental impact. Figure 1 The elongated LED lighting device 1 shown in FIG. 1 is sometimes referred to as an LED filament.

[0056] In this example, the carrier substrate has its longest extension in the y-direction, and the LEDs 3, 4 are arranged substantially in parallel on the carrier substrate 2. In the example where the LEDs are discontinuous 4, the spacing between the LEDs can form a plurality of gaps 5 between adjacent LEDs. In an alternative embodiment, the longest extension of the LEDs can be in a direction transverse or orthogonal to the longest extension of the carrier substrate. In more detail, when the longest extension of the carrier substrate is in the y-direction, the longest direction of the plurality of LEDs 3, 4 can be in the x-direction, or in any orientation relative to the x and y directions. It should be understood that each solid-state light-emitting element 3, 4 or each carrier substrate 2 has a first end and a second end, and the first end and the second end are arranged along the longest extension of the solid-state light-emitting element 3, 4 or the carrier substrate 2. The first end and the second end can also be arranged along or across any other extension of the solid-state light-emitting element 3, 4 or the carrier substrate 2.

[0057] The lighting device also includes an encapsulation 6 with a luminescent material, which here surrounds the carrier substrate and the LED. The encapsulation may, for example, include inorganic phosphor particles in a silica gel matrix material. Alternatively, the encapsulation may only partially surround the carrier substrate and the LED, or encapsulations of different components (e.g. different proportions of phosphor and silica gel matrix) may be used to surround different parts of the carrier substrate and LED of the same lighting device 1. The phosphor may be an inorganic phosphor, an organic phosphor and / or a quantum dot or quantum rod. Examples of inorganic phosphors include Lu3Al5O 12 (LuAG), yttrium aluminum garnet (YAG), ECAS, etc.

[0058] The package 6 is configured to provide wavelength conversion of light emitted from the LED, for example, when a blue LED element is used, at least a portion of the blue light emitted from the LED is absorbed by the phosphor and converted into yellow light and / or red light. The blue LED can, for example, emit light in the wavelength range of 420nm to 490nm, for example, such as emission in the wavelength range of 440nm to 460nm.

[0059] In addition to the blue LED, the lighting device may also include a red LED. The red LED emits red light. The red light emitted by the red LED may not be converted by the luminescent material. The red light emitted by the red LED may also present a flashing visual effect.

[0060] In several embodiments, the LED filament may include a plurality of LEDs, such as a linear array or a one-dimensional matrix of LEDs, wherein at least a 1x5, preferably a 1x10, more preferably a 1x20, or most preferably a 1x30 matrix is ​​arranged on each or either side of a substrate. In one example, the filament may include a 1x30 matrix of blue direct-emitting LEDs arranged on each or either side of a substrate, the substrate being made of transparent sapphire, the encapsulation being made in part of silica gel and phosphor (e.g., a YAG and K2SiF6 (KSIF) phosphor mixture), and the particles may be glass particles.

[0061] The LED filament preferably emits white light. The LED filament lamp preferably has a color temperature in the range of 2000K to 6000K, more preferably in the range of 2100K to 4000K, most preferably in the range of 2200K to 3000K (e.g., such as 2300K or 2700K). The LED filament lamp preferably has a color rendering index of at least 75, more preferably at least 80, most preferably at least 85. The white light emitted from the LED filament is preferably within 15SDCM from the BBL (black body locus), more preferably within 10SDCM, most preferably within 7SDCM, such as, for example, 5SDCM or 3SDCM.

[0062] In the example shown, the device also has first and second contact electrodes 7, 8, which are arranged at the first end 9 and the second end 10 of the carrier substrate 2. The contact electrodes provide electrical contact with an external power supply or any additional contact points. Of course, different arrangements of the electrodes are also possible.

[0063] According to the present invention, the lighting device further comprises a plurality of light-transmitting particles 11 of any geometric shape, which are partially or completely contained in the package. Suitable materials of these particles are glass, quartz, sapphire, plastic (such as PMMA or PC), silicone and the like.

[0064] Glass and silicone are preferred for demanding applications, ie, higher lumen output (high power) LED filaments.

[0065] The size of the particles (i.e., the average longest dimension extends) is between 0.4 and 1.5 times the thickness of the encapsulation layer on the light-emitting surface of the LED. According to one example, the size of the light-transmitting particles 11 can be at least 0.4 times or at least 0.8 times the thickness d of the encapsulation. Additionally or alternatively, the size of the light-transmitting particles can be at most 0.8 times or at most 1.2 times the thickness of the encapsulation 6.

[0066] Figure 2 illustrates Figure 1 Schematic cross-sectional side view of a lighting device 1. In this example, the cross section is across Figure 1The lines A, B, C and D in FIG. 2 are taken for a discontinuous LED portion 4, but it will be readily appreciated that the same explanations can apply to a cross section of a continuous LED portion 3 along the same lines. Section A in FIG. 2 shows a portion of an LED filament 1 with two example light rays emitted from an LED 4. Light ray 21 passes through encapsulation 6 and is fully wavelength converted and exits the LED filament 1 as converted light 21. On the other hand, light ray 22 will pass through the light transmissive particles and therefore be less wavelength converted (or not converted at all). Light ray 22 may also be scattered by its interaction with particles 11.

[0067] The color of the light 22 will depend on the size of the particles 11. In the case of a blue LED, larger particles (e.g., 0.8 to 1.2 times the thickness of the package 6) will result in more blue flashes, while smaller particles 11 (e.g., 0.4 to 0.8 times the thickness of the package 6) will result in flashes closer to the red end of the visible spectrum.

[0068] The particles may be located at different positions and distances relative to the LED element. The particles may be in direct or close contact with the LED element (as shown in sections A and D), or located on opposite sides of the carrier substrate 2 and the LED element 4 (such as shown in section B), and may not be present near the LED element 4 (such as shown in section B). Figure 2a In various other examples, it should also be understood that the LED filament 1 may have more than one light emitting element 3, 4 on either side and / or both sides of the carrier substrate, such as Figure 2b . Such light emitting elements 3, 4 may be provided as continuous light emitting parts 3, which are arranged continuously in the longest extension of the carrier substrate 2 in the x or y direction, or may be provided as discontinuous light emitting parts 4, which are arranged on either side of the carrier substrate 2. The discontinuous parts 4 may be arranged in any given orientation relative to the x or y direction. As an additional example, the lighting device 1 may have light emitting elements 3, 4, which have different optical and material properties.

[0069] Furthermore, the lighting device 1 may have more than one substrate 2 sealed in one package 6, for example Figure 2c as shown in .

[0070] The thickness d of the encapsulation 6 is generally such that it can completely surround the carrier substrate 2 and the LED elements 3, 4. However, this thickness may also exceed the thickness required to surround the substrate 2 and the LED elements 3, 4. However, one or more light-transmitting particles 11 may be only partially surrounded by the encapsulation 6.

[0071] As an example, the thickness d may be of the order of mm, for example, approximately 2-3 mm. If the thickness d is 2 mm, the average longest dimension of the particles should extend in the range 0.8-3 mm.

[0072] The package 6 may be provided substantially symmetrically around the light emitting device so that the distance from the light emitting surface 4a to the package boundary is substantially the same in all directions of the cross section (see e.g. Figure 2a ).exist Figure 2c In this case, it may be more relevant to consider the thickness as the larger distance d'.

[0073] Depending on the particle size and the number of particles per volume, the ratio of the total particle volume to the total volume (ie the volume of the package and the particles) can be above 10% and can even be around 30%.

[0074] Figure 3a-3c Different embodiments of the method for manufacturing a lighting device according to the present invention are illustrated.

[0075] exist Figure 3a In the embodiment, light-transmitting particles 11 are mixed in the encapsulant 6. In addition to the phosphor, the encapsulant may partially include a silica gel matrix material. More preferably, the encapsulant is made of a silica gel matrix material and inorganic phosphor particles.

[0076] The encapsulation is applied over and surrounds the LEDs 3, 4 and the substrate 2. Alternatively, the steps of including the light-transmitting particles 11 in the encapsulation 6 and applying the encapsulation 6 on the LEDs 3, 4 and the substrate 2 may be performed simultaneously.

[0077] In different methods, such as Figure 3b As shown in , a particle retaining layer 30 may be used. In this example, the particle retaining layer 30 is deposited on the carrier substrate 2, the particle retaining layer 30 at least partially covers the LEDs 3, 4 or is adjacent to the LEDs 3, 4, and the light-transmitting particles 11 are deposited in the particle retaining layer 30. The particle retaining layer 30 may be applied on either or both sides of the carrier substrate 2. Then, the encapsulant 6 is applied over the substrate 2, the LEDs 3, 4 and the particle retaining layer 30.

[0078] The light-transmitting particles 11 and the particle retaining layer 30 may be made of various combinations of organic silicon compounds and / or silica gel-based polymer compounds and copolymers or modified products thereof, including, for example, polydimethylsiloxane (PDMS) and the like.

[0079] Figure 3cAnother manufacturing method for manufacturing an LED filament 1 according to another exemplary embodiment of the present invention is illustrated. In this example, light-transmitting particles 31 are deposited directly on the carrier substrate 2 or the LEDs 3, 4. The light-transmitting particles 31 may have a uniform or non-uniform geometry. The light-transmitting particles 31 may be deposited so that the light-transmitting particles 31 at least partially cover the LEDs 3, 4. The deposition of the light-transmitting particles 31 may be on either or both sides of the carrier substrate 2. The deposition of the light-transmitting particles 31 may be performed using controlled and / or predetermined deposition parameters, including but not limited to different material compositions, deposition ratios, deposition times, deposition temperatures, deposition rates, and the like. The size, thickness, alignment, angle, and orientation of the particles may thus be manipulated with high precision. The method of mixing or depositing the light-transmitting particles may be any method known in the art, and as a non-limiting list may include evaporation, sputtering, spraying, and the like.

[0080] exist Figure 4 In FIG. 4 , a light bulb 40 is shown, which comprises a transparent shell 41 surrounding the assembly of lighting devices 1 according to the invention. The light bulb also has a connection terminal, here a conventional threaded base 42, to which the lighting device is electrically connected.

[0081] The present invention has now been described with reference to specific embodiments. It should be noted that the above embodiments illustrate rather than limit the present invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference numerals placed between brackets should not be interpreted as limiting the claims. The word "comprising" does not exclude the presence of other elements or steps other than those listed in the claims. The word "one" or "an" in front of an element does not exclude the presence of multiple such elements. In addition, other components of the lighting device (such as the first and second ends of the carrier substrate, or LED) may, for example, have any other curvature or orientation different from that shown in the figure. They may also be deposited so that their longest extension is in any direction between the x-direction, the y-direction, and the z-direction. Therefore, they do not need to be parallel or perpendicular to the longest extension of the substrate. It is also recognized by those skilled in the art that other conductive or semiconductor materials may be used as electrodes or used in LED elements of lighting devices. In addition, it will be readily understood by those skilled in the art that various combinations of phosphor particles and silica-based matrix materials may be used for encapsulation.

[0082] It should also be understood that in various examples, the size, thickness and area of ​​the carrier substrate, the number of contact electrodes or the geometry of the LED filament can vary. As a non-limiting example, an LED filament can have, for example, two substrates, each substrate having two LED elements. Thus, each substrate can be connected to a pair of electrodes to individually address each LED. The LEDs can be connected to the electrodes in series or in parallel.

[0083] It should also be understood that in other examples, the size, thickness, area, shape or number of the light-transmitting particles or LED elements can be appropriately changed. For example, the light-transmitting particles can have any symmetrical or asymmetrical geometric cross-sectional layout (such as rectangular, triangular, circular, elliptical, flat disk, etc.), or be provided and arranged in any other arbitrary or distorted layout. The light-transmitting particles can be homogeneous or inhomogeneous particles.

Claims

1. A lighting device for providing a flashing visual effect, the lighting device comprising: at least one solid-state light emitting element (3, 4) mounted on the carrier substrate (2), each solid-state light emitting element being configured to emit light from a light emitting surface (4a); an encapsulation (6) comprising a luminescent material, the encapsulation surrounding one or more of the luminescent surfaces of the at least one solid-state light-emitting element and configured to at least partially convert light emitted by the solid-state light-emitting element into wavelength-converted light; as well as a plurality of light-transmitting particles (11), at least partially contained within the encapsulation (6), the light-transmitting particles having an average longest dimension extending in the order of magnitude of the layer thickness of the encapsulation on one or more of the light-emitting surfaces, and wherein the carrier substrate (2) is transparent, and the encapsulation (6) is provided on two flat surfaces of the carrier substrate (2); wherein the at least one solid-state light emitting element (3, 4) is configured to emit blue light, and The light transmissive particles have an average longest dimension extending in the range of 0.8 to 1.2 times the layer thickness of the encapsulant for providing a blue flash; and / or The light transmissive particles have an average longest dimension extending in the range of 0.4 to 0.8 times the layer thickness of the encapsulation for providing a red flash. 2 . The lighting device according to claim 1 , wherein the light-transmitting particles have an average longest dimension extending in the range of 0.4 to 1.5 times the layer thickness of the encapsulation on one or more of the light-emitting surfaces.

3. The lighting device according to claim 1, wherein the light-transmitting particles (11) have a symmetrical shape.

4. The lighting device according to claim 1, wherein the light-transmitting particles (11) have an asymmetric shape.

5. A lighting device according to claim 4, wherein the extension of the light-transmitting particles in the vertical direction is at least twice the extension in the longitudinal direction and the transverse direction, wherein the vertical direction is orthogonal to or perpendicular to the carrier substrate, and the longitudinal direction is parallel to the longest extension of the lighting device, and the transverse direction is orthogonal to the vertical direction and the longitudinal direction.

6. The lighting device according to any one of claims 1 to 5, wherein the light-transmitting particles are randomly distributed in the encapsulation (6).

7. The lighting device according to any one of claims 1 to 5, wherein the light-transmitting particles are randomly distributed in a particle retaining layer (30), and the particle retaining layer is arranged on the carrier substrate (2).

8. The lighting device according to any one of claims 1 to 5, wherein the light-transmitting particles (11) have been deposited directly on the carrier substrate (2) or the light-emitting elements (3, 4).

9. A method for producing a lighting device having a flashing visual effect, the method comprising: - providing at least one solid state light emitting element (3, 4) mounted on a transparent carrier substrate (2), each solid state light emitting element being configured to emit light from a light emitting surface (4a); - providing an encapsulation (6) on two planar surfaces of the carrier substrate (2), the encapsulation (6) comprising a luminescent material, the encapsulation surrounding one or more luminescent surfaces of the at least one solid-state light-emitting element and being configured to at least partially convert light emitted by the solid-state light-emitting element into wavelength-converted light; as well as - providing a plurality of light-transmitting particles at least partially contained within the encapsulation (6), the light-transmitting particles having an average longest dimension extension in the order of magnitude of the layer thickness of the encapsulation on one or more of the light-emitting surfaces; wherein the at least one solid-state light emitting element (3, 4) is configured to emit blue light, and The light transmissive particles have an average longest dimension extending in the range of 0.8 to 1.2 times the layer thickness of the encapsulant for providing a blue flash; and / or The light transmissive particles have an average longest dimension extending in the range of 0.4 to 0.8 times the layer thickness of the encapsulation for providing a red flash.

10. The method of claim 9, wherein the light transmissive particles have an average longest dimension extending in the range of 0.4 to 1.5 times the layer thickness of the encapsulation on one or more of the light emitting surfaces.

11. The method according to claim 9, wherein the method further comprises: The light-transmitting particles are mixed or dissolved into the encapsulation (6) before the encapsulation is arranged on the carrier substrate.

12. The method according to claim 9, wherein the method further comprises: A particle retaining layer is arranged on the carrier substrate (2), and the light-transmitting particles (11) are deposited or mixed in the particle retaining layer.

13. The method according to claim 9, wherein the method further comprises: The light-transmitting particles (11) are directly deposited on the carrier substrate and / or the light-emitting element.

14. A light bulb (40), comprising: Transparent shell (41), At least one of the lighting devices (1) according to any of claims 1-8, being arranged within the housing and electrically connected to an electrical terminal (42) of the light bulb.

15. The light bulb of claim 14, wherein the lighting device is an LED filament.

Images