CN112384732A

CN112384732A - Flexible light emitting device

Info

Publication number: CN112384732A
Application number: CN201980045531.3A
Authority: CN
Inventors: 法塔赫·辛格; 阿诺·达蒂艾乐-奥布里耶; 杰罗姆·德尚
Original assignee: Linxens Holding SAS
Current assignee: Linxens Holding SAS
Priority date: 2018-07-09
Filing date: 2019-07-09
Publication date: 2021-02-19
Also published as: WO2020012117A1; FR3083590A1; EP3821168A1; KR20210031725A; FR3083590B1

Abstract

The present invention relates to a light emitting device including: a flexible support strip (1) having a length and a width; LED chips (2) arranged on the main surface (10) of the support strip (1) and distributed in a continuous pattern over the length of the strip; an electronic module (3) mounted on the support bar (1); a conductive track formed on at least one of the surfaces of the support strip and electrically connecting together the set of LED chips (4) and the set of electronic modules (3); and at least one encapsulation layer (6) covering at least the assembly of LED chips (2) and letting pass all or part of the light generated by the LED chips (2), the encapsulation layer (6) extending continuously in said continuous pattern over the entire length of the support strip (1).

Description

Flexible light emitting device

Technical Field

The present invention relates to a flexible light emitting device based on Light Emitting Diodes (LEDs), such as a flexible light emitting strip provided with LEDs.

Background

Basically, an LED chip typically comprises at least one p-n junction formed between a region of semiconductor material doped with a p-type doping and a region of semiconductor material doped with an n-type doping. The electrical connection terminals connected to each of the doped regions can be used to inject electrical current and thus emit optical radiation in a wavelength range determined by the properties of the semiconductor material used. The light emitted by the LED chip is typically substantially monochromatic or within a given wavelength range. In addition, the LED chips may be associated with luminophores capable of absorbing a portion of the optical radiation emitted by the LEDs and capable of emitting light at wavelengths other than the wavelength of the LED chips. For example, the emitter layer may be deposited on the LED chip.

Conventionally, for practical and commercial reasons, each LED chip is initially packaged, i.e. mounted in a housing or on a substrate, and then covered with a package body, e.g. silicone, in order to form an LED module or a packaged LED. Contact pads electrically connected to the electrodes of the LED chip are then typically provided on the substrate in order to enable the packaged LED to be electrically connected to other components of the circuit. An example of the LED module is a COB (chip on board) LED module in which an LED chip is directly attached in a recess formed in a substrate provided with various connectors and then covered with a protective dome. Other examples of LED modules are SMD (surface mounted device) LED modules, which are made up of a set of several LED modules soldered onto the face of a printed circuit, and are usually in the form of dots, in particular yellow in color because of the presence of a light emitter.

Packaged LEDs of this type can then be soldered onto various supports (which may be rigid or flexible) provided with electrical traces and active and/or passive electronic components required for powering and operating the packaged LEDs, in order to produce a light-emitting object.

For example, by attaching the encapsulated LEDs specifically to a flexible strip, a flexible and divisible light emitting strip can be formed. The packaged LEDs are arranged one after the other along the length of the strip at a constant pitch (typically at least 10mm, and for high density LED strips about 5 mm). Smaller spacings between LEDs cannot be envisaged for mechanical reasons, such as loss of flexibility of the light emitting strips and risk of degradation due to vibrations between LEDs. In general, the size of the package or housing of the LEDs imposes a limit on the minimum distance between two LEDs on the strip. In particular, the minimum distance is generally given by the sum of a first value equal to 1.5 times the height of the housing or package and a second value equal to twice the distance between the inner wall of the package and the LEDs arranged in the housing. The strip is also provided with printed circuits and electronic components necessary for the operation of the LEDs. The strip includes a cut line, allowing the strip to be cut to a predetermined length without altering the operation of the LEDs. However, due to the spacing between the two packaged LEDs, the light diffused by the light-emitting bars shows alternating spots and dark areas. In order to improve the uniformity of the light diffused by the light-emitting bars, one solution consists in recessing the light-emitting bars in a rigid profile formed by a diffusing material. Another solution consists in covering the strip with a diffusing layer, which also acts as a protective layer. A light bar of this type is described, for example, in document US 2012/0002417 (in which SMD LEDs are used). However, the height of the walls of the housing also constitutes a limitation of the uniform diffusion of light by the light-emitting bars (since this wall imposes an exit angle) and therefore a limitation of the diffusion angle of light (which is about 120 °), which means that no light is emitted at the level of the cross-section of the packaged LED.

Disclosure of Invention

In this case, the invention therefore proposes a flexible and divisible lighting device which is capable of diffusing light more uniformly and which is suitable for functional lighting and not only decorative lighting.

Accordingly, the present invention provides a light emitting device comprising:

-a flexible support strip having a length and a width;

-LED chips arranged on the main surface of the support strip and distributed in a continuous pattern over the length of the strip;

-an electronic module mounted on the support bar;

-electrically conductive tracks formed on at least one of the surfaces of the support bar and electrically connecting together the LED chip set and the electronic module set;

at least one encapsulation layer covering at least the assembly of LED chips and allowing all or part of the light generated by the LED chips to pass through, the layer extending in said pattern in a continuous manner over the LED chips and over the entire length of the support strip.

Thus, in contrast to the prior art light bar presented above, which uses packaged LEDs, the light emitting device of the present invention integrates directly unpackaged LED chips (i.e. bare semiconductor or exposed semiconductor material), and the assembly of these LED chips is covered by a common encapsulation layer, which is deposited continuously on all the LED chips along a support strip and in a continuous pattern, such as a linear pattern, which substantially corresponds to the pattern defined by the LED chips distributed along the support strip. In other words, the encapsulation layer has no discontinuity over the entire length of the support bar. The LED chips may be selected to generate light radiation of the same or different wavelengths.

Because the minimum distance allowed between two adjacent LED chips is less than the minimum distance allowed between two packaged LEDs, the number of LED chips disposed on a given length of strip can be significantly greater than the number of packaged LEDs of a strip of the same length. In particular, the density of the LEDs can be increased by a factor of 10. This means that a high linear density of LED chips results in the light spots generated by the LED chips being closer together and thus a more uniform visual appearance of the light diffused along the light emitting bar. In practice, the minimum distance between two adjacent LED chips is about 10 μm. In addition, the plurality of LED chips may be constituted by different types of LED chips. In particular, any type of LED chip may be used, and in particular low, high and medium power LED chips, in order to provide functional lighting and/or purely decorative lighting. In addition, each of the LED chips may be provided with a light-emitting layer. Thus, several LED chips emitting at different or the same wavelength may be mounted on the support bar according to the desired visual effect. In particular, the plurality of LED chips may comprise LED chips emitting in the visible spectrum and/or outside the visible spectrum, in particular in the infrared and/or ultraviolet.

Advantageously, the LED chip is connected to the conductive tracks by different connection means, such as wires, direct soldering, conductive adhesive, etc. Depending on the position of the conductive tracks on the support, it is possible to envisage connections through micro-vias, i.e. via holes or pins passing through the thickness of the support strip. Thus, according to a variant, the LED chips, the electronic components and the conductive tracks are all on the same surface of the support strip, and in particular on the main surface. According to another variant, the conductive tracks are formed on a surface opposite to the main surface. In particular, the minor surface of the support strip opposite the major surface may be covered with a conductive layer, for example formed of copper, in which conductive tracks are formed. According to another variant, the main and secondary surfaces of the support strip may be covered with a metal layer formed of the same or different material. Thus, the main surface may be covered with a conductive layer, for example formed of copper, in which conductive tracks are produced, and the sub-surface may be covered with a reflective layer, for example formed of aluminum, in order to ensure that the light radiation emitted by the LED chip can be reflected. Both the major and minor surfaces may be covered with the same type of metal layer, e.g. a metal layer formed of copper, one providing electrical connection between the LED chip and the electronic component and the other providing heat dissipation and/or reflection.

In fact, the encapsulation layer must cover the smallest assembly of LED chips distributed on the support strip and optionally the electrical connection lines connecting the LED chips together, in order to form at least one protective layer. In other words, the size of the encapsulation layer across the width of the support bar will be a function of the size of the LED chips to be covered and their placement across the width of the support bar. As an example, for LED chips having dimensions of 320 μm over the width of the support strip and distributed one after the other along the support strip, the encapsulation layer over the width of the support strip may be a minimum of about 350 μm. Thus, it should be understood that if a plurality of LED chips are positioned along the width of the support strip, the width of the encapsulation layer may be wider so as to cover all of the LED chips.

Advantageously, the encapsulation layer is deposited only on the major (main) surface of the support strip that receives the LED chips, and the encapsulation layer may cover the support strip over all or part of its width. For example, the encapsulation layer may cover 5% to 100% of the width of the support strip, e.g. 1mm for a support strip width of 10 mm. Thus, the encapsulation layer may cover only the LED chip, or may also cover all or part of the conductive traces and/or all or part of the electronic module.

According to a variant, the width of the encapsulation layer may correspond to 100% of the width of the bar, i.e. the encapsulation layer covers the entire width of the support bar, or it may be greater than 100%, i.e. the encapsulation layer is wider than the support bar. According to another variant, the encapsulation layer may extend beyond the major surfaces of the support strip and then cover all or part of the minor surfaces of the support strip. Thus, the support bars may be embedded in the encapsulation layer.

According to another embodiment, a plurality of assemblies of LED chips may be distributed over the width of the support strip, the LED chips of each assembly being distributed over the length of the support strip in a continuous pattern, the patterns of the assemblies of LED chips may be the same or different, and the plurality of assemblies of LED chips may be covered with a common encapsulation layer. For example, the support strip may include several LED chip lines covered by the same encapsulation layer.

The electronic module may be entirely disposed outside of the encapsulation layer or covered by the encapsulation layer. The electronic module is in particular constituted by active and/or passive components required for the operation of the LED chip, such as electrical conditioning components suitable for supplying a constant current (typically between 1mA and 2000 mA) or providing a constant voltage (typically 5V, 12V, 24 or 48 volts) to the low-power and/or medium-power LED chips.

The encapsulation layer may be made of materials conventionally used for coating or encapsulating semiconductors, such as silicone, urethane, or epoxy. In addition, the encapsulation layer may integrate different types of particles depending on the characteristics to be provided. For example, when the LED chip used does not contain a light emitter, the encapsulation layer may contain a light emitter. The encapsulation layer may also include diffusing particles (typically titanium dioxide, TiO)₂Zirconium dioxide ZrO₂Copolymers, hollow fillers, bubbles, etc.). For example, the encapsulation layer may comprise a filler having properties that improve the fire resistance properties of the encapsulation layer, such as a flame retardant filler or an endothermic filler, e.g. air bubbles or inorganic particles. According to a variant, the various particles or fillers may be distributed in a uniform manner in the encapsulation layer. The concentration of particles or fillers in the thickness of the encapsulation layer may also vary depending on the distance relative to the LED chip. In other words, in addition to the function of protecting the LED chip, other functions may be imparted to the encapsulation layer by including suitable particles or fillers. By way of example, the encapsulation layer may be colored, opaque, or transparent, and may be configured so as to provide mechanical protection, or may actually be hermetic to certain liquids or gases, or may actually block the propagation of heat or fire.

According to a variant, the encapsulation layer may be formed by several layers and may for example be formed by an inner layer covering at least the LED chip and an outer layer covering the inner layer. The inner layer is in direct contact with the LED chip and preferably contains a light emitter, forming a light conversion layer. This inner layer may for example cover 5% of the width of the supporting strip. Advantageously, the inner layer covers the fewest LED chips and optionally the connecting wires for the LED chips. The outer layer covers the inner layer and may be transparent or colored, e.g., white. Of course, particles or fillers such as those mentioned above may be incorporated into this outer layer. The outer layer may also cover up to 100% of the width of the support strip, or it may be wider than the support strip and optionally cover all or part of the second surface of the support strip. As mentioned above, the support strip may comprise several lines of LED chips covered with a common outer layer. In addition, the encapsulation layer may include several inner layers each covering one or more LED chip lines, or include a single inner layer covering all LED chip lines.

The encapsulation layer may have a profile in the shape of a substantially dome. However, any other profile may be envisaged. The maximum thickness of this encapsulation layer is preferably between 0.2mm and 10mm, typically 2 mm. In the particular case where the encapsulation layer is formed from an inner layer and an outer layer, the maximum thickness of the inner layer may be between 0.2mm and 2mm, typically 0.6mm, and the maximum thickness of the outer layer may be between 0.5mm and 10mm, typically 2 mm.

According to an embodiment, the continuous pattern is rectilinear. In other words, the LED chips are arranged in line one after another along the supporting bar. The pattern may also have a curved line, for example it may be in the form of a wave, but it may also be as a letter, a word or indeed as a sign.

According to another embodiment, the support bar may have several continuous patterns (linear or non-linear, identical or different, in other words, several assemblies of LED chips may be mounted on the support bar, and each assembly of LED chips extends along the support bar according to a pattern and is covered by an encapsulation layer that extends continuously along the support bar in a corresponding pattern.

As an example, the support strip itself may be formed of polyvinyl chloride (PVC), polyethylene terephthalate (PET), which may be based on a viscoelastic polymer (VEP), or of a viscoelastic polymer (VEP)

Or formed of Polycarbonate (PC), and it may be divisible. In particular, the support strip may comprise cutting lines provided at regular intervals, allowing the strip to be cut without altering the operation of the groups of LED chips arranged between two consecutive cutting lines. The spacing between two consecutive cutting lines may be of the order of a few millimetres, for example between 5mm and 500mm, typically between 10mm and 50 mm. For practical reasons, at each cutting line, the support strip is preferably provided with electrical contact points, in particular in order to achieve a quick electrical connection of the light-emitting strips. Proper placement of the conductive traces and electronic modules between the cut lines can be used to ensure proper operation of the LED chip sets disposed between the cut lines. In practice, these contacts are exposed and not covered by the encapsulation layer.

The present invention also relates to a method for manufacturing the above light emitting device, comprising:

-arranging LED chips on a major surface of a flexible support strip, arranging electronic modules and conductive tracks on the flexible support strip, the LED chips being distributed in a continuous pattern over the length of the support strip, the conductive tracks electrically connecting together the LED chip groups and the electronic module groups;

-continuously depositing an encapsulation layer covering at least the LED chip, the encapsulation layer extending continuously in said pattern over the entire length of the strip and allowing all or part of the light generated by the LED chip to pass through.

According to a variant, before depositing the encapsulation layer, the method further comprises, in succession, depositing two lines of material along the main surface of the support strip, the two lines of material defining a recess containing the LED chip, the encapsulation layer then being deposited inside this recess. In other words, the two lines of material constitute a holding line forming a channel into which the material is injected to form the encapsulation layer. The two retaining lines, which may be transparent or opaque, but may also be colored, may be made of silicone or polyurethane. The retaining line may have the same physical properties as the encapsulation layer. For example, the holding line may be configured so as to have a predetermined reflectivity with respect to radiation emitted by the LED chip.

According to another variant, the retaining wires may be replaced by channels defined on or in the support strip, which channels extend continuously along the support strip.

According to a variant, the method may further comprise depositing a plurality of encapsulation layers distributed over the width of the support strip. The support strip therefore preferably has several different encapsulation layer lines across its width.

According to another variant, the method comprises a first deposition of at least one inner layer containing the luminophores and a second deposition of an outer layer covering the inner layer.

The manufacturing method may further comprise a final step of winding the strip around a non-planar support. Thus, very long support bars can be used.

In practice, the support bars may have the following dimensions:

-length: typically from a few centimetres to a few hundred meters, for example 10m, 40m or indeed 3m, or even 300 m;

-width: typically between 5mm and 70mm, for example 10 mm;

-thickness: typically between 0.1mm and 1mm, for example 0.4 mm.

Drawings

Other characteristics and advantages of the invention will become apparent from the following description, given by way of non-limiting illustration and made with reference to the accompanying drawings, in which:

fig. 1 is a perspective view of a schematic representation of a portion of a flexible strip containing aligned LED chips and electronic components according to an embodiment of the invention;

figure 2 is a perspective view of a schematic representation of a portion of a flexible strip having its width partially covered by an encapsulation layer according to an embodiment of the invention;

figure 3 is a view along the section a-a of the strip portion of figure 2;

figure 4 is a perspective view of a schematic representation of a portion of a flexible strip in which the encapsulation layer is formed by an inner layer and an outer layer according to an embodiment of the invention;

figure 5 is a view along the section a-a of the strip portion of figure 4;

FIG. 6 is a cross-sectional view of a light bar according to another embodiment of the invention;

fig. 7 is a plan view of the main surface of a support strip on which a single encapsulation layer has been deposited according to a variant;

fig. 8 is a plan view of the main surface of a support strip on which two encapsulation layers have been deposited according to another variant;

fig. 9 is a plan view of the main surface of a support strip on which several encapsulation layers have been deposited according to another variant;

fig. 10 is a plan view of the main surface of a support strip on which two encapsulation layers have been deposited in a linear pattern with a curve according to another variant;

fig. 11 is a perspective view of a schematic representation of a portion of a flexible strip integrating two rows of LED chips according to another embodiment of the invention;

FIG. 12 is a cross-sectional view of a portion of the strip of FIG. 11 covered with an encapsulation layer according to one embodiment of the invention;

FIG. 13 is a perspective view of a schematic representation of a portion of a flexible strip comprising different LED chip wires arranged alternately according to another embodiment of the invention,

it should be noted that in the figures, like reference numerals designate identical or similar elements and that the various structures are not to scale. In addition, for the sake of clarity, only the elements necessary for understanding the invention are shown in these figures.

Detailed Description

A light bar according to a specific embodiment of the present invention will now be described.

Referring to fig. 1, a light bar according to one embodiment of the present invention includes a flexible support strip 1 including a major surface 10 and a minor surface 11 opposite the major surface 10. The LED chip 2 and the electronic components 3 required for the operation of the LED chip are mounted on a main surface 10 of this flexible strip. In the example shown in fig. 1, the various LED chips 2 are arranged in a regular manner over the entire length of the supporting strip 1. The linear density of the LED chips 2 along the supporting strip 1 may be very high and the minimum distance d between two adjacent LED chips may be about 10 μm. Depending on the application, the distance between two adjacent LED chips may be larger, or indeed may vary along the support strip 1. The electronic components associated with the LED chips are advantageously arranged near the edges of the support strip on the same main surface, but other arrangements are also conceivable. The main surface 10 of the supporting strip 1 is also provided with cutting lines 4 at regular intervals, so that the strip can be cut without changing the function of the groups of LED chips provided between two consecutive cutting lines. Electrical contact points 5 are also provided on the main surface 10 of the support strip 1 at the level of the cutting lines 4, in order to allow a quick electrical connection of the luminous strips. Conductive traces (not shown for clarity) are also formed on this major surface 10 in a manner that connects together a plurality of LED chip sets and electronic components. The conductive traces may be on the major or minor surfaces of the support strip.

All the LED chips arranged on the support bar in this way are covered with a common encapsulation layer, which therefore extends continuously over the entire length of the support bar. The encapsulation layer is selected from materials suitable for allowing light emitted by the LED chip to pass through. Different particles may also be incorporated into the encapsulation layer in order to provide it with specific properties, such as blocking the propagation of flames, better diffusing the light emitted by the LED chip, or indeed converting the light radiation emitted by the LED chip. Thus, the encapsulation layer may comprise luminophores, but may also comprise diffusing particles or flame retardants or endothermic fillers.

Additionally, the encapsulation layer may be deposited on the major surfaces of the support strip in a manner that covers all or part of the width of the support strip. Thus, in the variant shown in fig. 2 and 3, the encapsulation layer 6 covering the LED chip covers only a part of the width of the support strip 1. Only the encapsulation layer and the support bars are shown in fig. 2 and 3. For example, the encapsulation layer may cover 10% of the width of the support strip 1, and the maximum thickness e of the encapsulation layer in a direction perpendicular to the main surface 10 is about 0.6 mm. The encapsulation layer may contain luminophores in order to form a layer for converting the light radiation emitted by the LED chip. Of course, LED chips containing emitters may be used, and in this case, it is not necessary to include emitters into the encapsulation layer.

According to a variant, the encapsulation layer may be formed by an inner layer covering at least the LED chip and an outer layer covering the inner layer. The inner layer is in direct contact with the LED chip and preferably contains a luminophore, so that a luminescence conversion layer is formed. The inner layer may cover 10% of the width of the support strip. The outer layer covers the inner layer and is preferably transparent. Of course, particles or fillers (such as those mentioned above) may be incorporated into this outer layer. The outer layer may also cover up to 100% of the width of the strip.

According to another variant, illustrated in fig. 4 and 5, the encapsulation layer may be formed by several layers, each of these layers having a well-defined function or characteristic. For example, the encapsulation layer may be formed by an inner layer 60 containing the luminophores, in particular in order to perform the function of conversion of light radiation, and an outer layer 61 configured to perform the function of mechanical protection and/or diffusion and/or retardation of fire. The outer and inner layers may have the same or different profiles. For example, and as shown in fig. 6, the thickness of the outer layer around the inner layer may be irregular.

Following the principles disclosed above, the support strip may include one or more assemblies of LED chips, with the LED chips of each assembly being disposed on the support strip in a continuous pattern (e.g., linear) along the entire support strip. Each assembly of LED chips is covered with a common encapsulation layer as discussed above in a pattern substantially corresponding to the pattern of LED chips on the support strip. In other words, if the support strip comprises several components of LED chips, several encapsulation layers may thus be provided on the support strip. Each encapsulation layer extends along the support strip in a continuous pattern corresponding to the arrangement of the components of the LED chip it covers. Thus, it is conceivable to have several consecutive patterns on the same support strip.

Of course, other configurations are also contemplated. For example, a common encapsulation layer may cover multiple components of the LED chip. The encapsulation layer may be formed of several inner layers and one outer layer, each inner layer covering one or more components of the LED chip, and the outer layer covering all inner layers.

A variant with a single encapsulation layer 6 is shown in fig. 7. The LED chips are arranged on the supporting bar 1 in a straight line pattern. The encapsulation layer 6 preferably contains a light emitter.

Another variant with two

encapsulation layers

6a and 6b is shown in fig. 8. The main surface 10 of the support strip 1 comprises two assemblies of LED chips, each assembly being distributed in a rectilinear pattern along the support strip. Two

encapsulation layers

6a and 6b are deposited. The two layers may have the same or different properties. For example, the encapsulation layer 6a of fig. 8 may contain a light emitter so as to emit white light having a first color temperature (e.g., warm tone), and the second encapsulation layer 6b of fig. 8 may contain a light emitter so as to emit white light having a second color temperature (e.g., cool tone) different from the first color temperature. In the same principle, several encapsulation layers may be provided on the same support strip, so that each encapsulation layer is capable of emitting light of a different color. For example, as shown in fig. 9, the encapsulation layers 6a to 6d may be configured so as to diffuse white light having different color temperatures, and the encapsulation layers 6e to 6h may be configured so that each encapsulation layer may diffuse light having a different color (such as red, blue, green, orange, etc.).

In addition, the linear pattern may also have a curve (as shown in fig. 10), in which the encapsulating layers 6i and 6j are in the form of a pattern substantially in the form of waves. The linear pattern may also be in the form of letters or logos.

The configuration of several components with LED chips is shown in fig. 11 and 12. The light bar of fig. 11 includes LED chips 2a forming a first component and LED chips 2b forming a second component. Both components of the

LED chips

2a, 2b may be covered with a common encapsulation layer, as shown in fig. 12. As shown in fig. 8, each component of the LED chip may also be covered with a different first layer, and a second layer may be deposited to cover all of the first layers. The

LED chips

2a and 2b may be of the same or different types. The

LED chips

2a and 2b may also be arranged along the same line, for example, in an alternating manner, as shown in fig. 13. An arrangement of this type is suitable, for example, for forming a light-emitting strip of diffuse light, wherein the color temperature can be adjusted by operating one or the other component of the

LED chips

2a, 2 b.

According to another embodiment, it is also possible to envisage a discontinuous deposition over the entire length of the support strip. For example, portions of the strip may be defined and the encapsulation layer deposited successively on each strip portion. In general, the support bars have encapsulation layer segments.

Indeed, the LED chips may be mounted and wired to the support bar according to a configuration that may still allow other components to function properly and provide continuous illumination in the event of a failure of one or more components, such as a wire break on one or more components or degradation of one or more LED chips. In particular, the supply of power to each component (for example an LED chip) can be ensured by combining series and parallel wired circuitry. The parallel wiring allows power to be maintained to the LED chips in the event of failure of one or more LEDs on the support strip. In addition, the absence of light output in one or more defective or inactive LED chips is compensated by an increase in the light emitted by the still active (i.e. non-defective) LED chips connected in parallel (due to an increase in the current through them). This compensation of the output ensures visual continuity of the light, making the defect invisible.

In addition, the support bars may include conductive traces dedicated to supplying current in order to reduce in-line voltage loss (in-line voltage loss), and thus may increase the length of the powered light emitting device without losing output. In addition, the cross-section (thickness and width) of these conductive tracks is preferably selected according to the predetermined length of the light emitting device to be powered, and therefore according to the power to be used. In addition, the maximum cross-section of the conductive tracks can also be selected by taking into account the desired mechanical flexibility of the light-emitting device or by taking into account the limitations on the dimensions that can be used (in particular the width of the product).

The presented structure thus provides great flexibility in the manufacture of the lighting device, both in terms of its size and in terms of visual appearance (due to the more uniform emission of light), and in terms of the possibility of forming a very wide variety of luminous patterns.

Claims

1. A light emitting device comprising:

-a flexible support strip (1) having a length and a width;

-LED chips (2) arranged on a main surface (10) of the support strip (1) and distributed in a continuous pattern over the length of the strip;

-an electronic module (3) mounted on the support bar (1);

-electrically conductive tracks formed on at least one of the surfaces of said support strip and electrically connecting together the set of LED chips (4) and the set of electronic modules (3);

-at least one encapsulation layer (6) covering at least the assembly of LED chips (2) and allowing all or part of the light generated by said LED chips (2) to pass through, said encapsulation layer (6) extending in a continuous manner in said continuous pattern over the entire length of said support strip (1).

2. The device according to claim 1, wherein the encapsulation layer (6) covers all or part of the width of the support strip (1).

3. The device according to claim 1 or 2, wherein the electronic module (3) is entirely arranged outside the encapsulation layer (6).

4. The device of claim 1 or 2, wherein the encapsulation layer covers the electronic module and the LED chip.

5. The device according to any of claims 1 to 4, wherein the encapsulation layer (6) comprises a light emitter.

6. The device according to any of claims 1 to 5, wherein the encapsulation layer (6) comprises diffusing particles.

7. The device according to any of claims 1 to 6, wherein the encapsulation layer (6) comprises a flame retardant filler or a heat absorbing filler.

8. The device according to any of claims 1 to 6, wherein the encapsulation layer (6) is formed by a plurality of layers including an inner layer (60) covering at least the LED chip (2) and an outer layer (61) covering the inner layer (60).

9. The device of claim 8, wherein the inner layer (60) includes a light emitter.

10. The device of any one of claims 1 to 9, wherein the linear pattern is linear or curved.

11. The device of any one of claims 1 to 10, wherein the support strip has a plurality of identical or different continuous patterns distributed across the width of the support strip.

12. A method for manufacturing a light emitting device according to any of the preceding claims, comprising:

-arranging LED chips, electronic modules and electrically conductive tracks on a main surface of a flexible support strip, said LED chips being distributed in a continuous pattern over the length of said strip, said electrically conductive tracks electrically connecting together a group of LED chips and a group of electronic modules;

-continuously depositing an encapsulation layer covering at least the LED chip, the encapsulation layer continuously extending in the continuous pattern over the entire length of the strip and allowing all or part of the light generated by the LED chip to pass through.

13. The method of claim 12, wherein prior to depositing the encapsulation layer, the method further comprises depositing two lines of material continuously along the major surface of the support strip, the two lines of material defining a recess containing the LED chip, and then depositing the encapsulation layer within this recess.

14. The method of any one of claims 12 to 13, wherein the method further comprises depositing a plurality of encapsulation layers distributed over the width of the support strip.

15. A method according to any one of claims 12 to 14, wherein the deposition of the encapsulation layer comprises a first deposition of an inner layer comprising a light emitter and a second deposition of an outer layer covering the inner layer.

16. A method according to any one of claims 12 to 15, wherein the method includes a final step of wrapping the strip around a non-planar support.