Reducing glare of lighting device

Abstract

A lighting device (10) is provided. The lighting device (10) comprises a light-emitting element (11) and a translucent enclosure (20) surrounding the light-emitting element (11) and having a surface area at least three times the light-emitting area of the light-emitting element (11), where the enclosure (20) is coated with a phosphor layer (22) having a thickness of 0.05 mm to 1.0 mm, and the phosphor layer (22) is configured to block less than 30% of visible light emitted by the light-emitting element (11).

Description

Technical Field

[0001] The present invention generally relates to glare reduction. In particular, the present invention relates to a lighting device including a glare reduction feature. Background Art

[0002] Home and professional environments contain a large number of lighting devices for producing functional lighting, ambient lighting, mood lighting, accent lighting or task lighting. It is well known that people need high lux levels to read, do tasks or even for their health. When lighting devices are used as such high flux sources, for example providing 800 lumens, these lighting devices may become very dazzling and uncomfortable to use: the brightness of the light-emitting elements is too high for direct viewing. Some lighting devices modify the light-emitting elements to reduce glare, for example by increasing their effective area. However, such light-emitting elements are not always appropriate for practical reasons or aesthetic reasons. Thus, it may be desirable to reduce glare in another way. Summary of the invention

[0003] It is therefore an object of the present invention to provide a lighting device with reduced glare. The inventors have realised that by coating the envelope of the lighting device with a phosphor layer without affecting the light emitting elements, the active area of ​​the lighting device can be increased, thereby reducing glare.

[0004] According to a first aspect of the invention, this object is achieved by a lighting device having the features of the independent claim. Preferred embodiments are defined in the dependent claims.

[0005] Therefore, according to a first aspect of the present invention, there is provided a lighting device comprising a light emitting element; a translucent capsule surrounding the light emitting element and having a surface area at least three times larger than a light emitting area of ​​the light emitting element; wherein the capsule is coated with a phosphor layer having a thickness of 0.05 mm to 1.0 mm, and the phosphor layer is configured to block less than or equal to 30% or 20% of visible light emitted by the light emitting element.

[0006] The phosphor layer will absorb some of the light emitted by the light emitting element and re-emit it (by electron relaxation photon emission).By coating the capsule with the phosphor, the capsule will emit light along its coated surface area, further increasing the light emitted across a larger area of ​​the capsule.

[0007] The surface area of ​​the encapsulant is at least three times, such as at least five times or at least ten times or at least twenty times, the light emitting area of ​​the light emitting element.

[0008] Therefore, the present invention is based on the idea of ​​providing a phosphor layer which, by absorbing the light emitted by the light emitting element and re-emitting it, can emit light in a larger area, i.e., in the entire surface area of ​​the capsule or at least 50% to 80% thereof. The surface area of ​​the capsule can be 10 to 20 times or even 50 times that of the light emitting element, depending on the type of light emitting element and capsule. Thus, the effective area of ​​the light emitting element is increased and glare is reduced.

[0009] The light emitting element can be used to provide functional lighting. The light from the phosphor layer can give the lighting device a white glow or a colored glow. In this way, it can deliver high flux with low glare, thereby achieving functional light that meets the standards of eye comfort or white light with an aesthetically pleasing colored glow effect.

[0010] The light emitting element can be an LED filament, a light guide LED or a direct light emitting LED.

[0011] The lighting device may be, for example, a light bulb or a luminaire.

[0012] The capsule may be of any shape (such as a sphere), and may be flat or curved (in one or two directions).

[0013] Therefore, the present invention has the advantage of reducing glare while the lighting element remains unchanged.

[0014] According to an embodiment of the invention, the phosphor is an organic phosphor (as opposed to a normal LED phosphor).

[0015] Thus, the main components of the phosphor layer are organic substances and phosphors, ie carbon, hydrogen, nitrogen and for example fluorine or any other halogen.A well-known group of materials is the group of molecules called perylene diamides.

[0016] According to an embodiment of the invention, the thickness of the phosphor layer is different in different parts of the envelope.

[0017] Different thicknesses may be used to selectively increase re-emitted light in certain portions of the envelope (eg, portions where light from the first and / or LEDs does not reach).

[0018] According to an embodiment of the present invention, the phosphor layer includes scattering particles different from the phosphor.

[0019] Scattering particles can change the color or hue of the light emitted by the lighting device.

[0020] According to an embodiment of the invention, the envelope is only coated with the phosphor layer.

[0021] Some lighting devices are coated, for example, with an amber color for aesthetic purposes, however, such coatings absorb 5% to 20% of the light and do not re-emit the absorbed light, thereby reducing the optical efficiency of the lighting device. Such coatings are particularly common when the light emitting element is a filament. A phosphor layer can replace the need for other layers (such as an amber layer), thereby improving efficiency because the phosphor layer re-emits the absorbed light, such as greater than 75% or greater than 85% of the absorbed light (where the loss may be partially due to the Stokes shift).

[0022] According to an embodiment of the present invention, the light emitting element filaments include individually controllable ultraviolet (UV) light sources, and wherein the phosphor layer is configured to absorb UV light and re-emit it as visible light.

[0023] The UV light may be, for example, in the UVA and / or UVB spectrum. The re-emitted light may be entirely in the visible light spectrum.

[0024] This may enable a more specific control of the lighting device 10. For example, only non-visible UV light may be emitted from the light emitting elements, and the phosphor layer (re)emit visible light, so that the envelope is illuminated without the light emitting elements being visible.

[0025] According to an embodiment of the present invention, the light emitting element is an LED filament.

[0026] LED filaments can be seen as particularly sparkling. Further, this also combines the benefits of filament technology with the benefits of phosphor technology to form a new retrofit lighting device.

[0027] According to an embodiment of the present invention, the phosphor layer is patterned.

[0028] Thereby, the light emitted by the lighting device may reproduce a pattern. The phosphor layer may comprise a pattern of phosphor spots. These spots may be very small (such as less than 1 mm in diameter) and may not be visible to the naked eye.

[0029] According to an embodiment of the present invention, the phosphor layer comprises ground particles of a phosphor-doped polymer.

[0030] The ground particles scatter light and are simple to manufacture.

[0031] According to an embodiment of the invention, the lighting device further comprises an LED, which is arranged in connection with the encapsulation such that the encapsulation acts as a light guide for the LED.

[0032] The light from the LED is coupled into a capsule made of a translucent material with relatively low light scattering properties, giving the lighting device a white glow or a colored glow. In this way, it can deliver high flux with low glare, achieving functional light that meets the standards of eye comfort or white light with an aesthetically pleasing color glow effect.

[0033] The LED can be a group of direct-emitting LEDs or micro-LEDs or single-sided emitting LED filaments.

[0034] Further, by using two light emitting elements, each light emitting element may emit fewer lumens to achieve the same flux level, thereby further reducing glare.

[0035] According to an embodiment of the invention, the light emitting element and the LED are individually controllable.

[0036] Thus, different lumens, colors and / or color temperatures may be set for each of the light emitting elements and LEDs.

[0037] According to an embodiment of the invention, the capsule is configured to emit light when used as a light guide for an LED such that at least 50% of the area of ​​the capsule emits light with a luminance that differs less than 5 times from an average luminance of the capsule.

[0038] Luminance is measured in candela per square meter and can be considered as brightness. The area can be, for example, an area of ​​the enclosure or a projection of light emitted by a lighting device. Any known luminance measurement method can be used to ensure that the difference between the one or more parts of the enclosure and the average value does not exceed five times.

[0039] Thus, the capsule emits light that is relatively evenly distributed along the area of ​​the capsule, further increasing the effective area of ​​the emitted light.

[0040] According to an embodiment of the present invention, the LED is configured to emit light having a minimum luminance threshold when the light emitting element emits light above a predetermined luminance threshold.

[0041] By causing the LED to emit light having a minimum luminance threshold when the light emitting element emits light above a predetermined luminance threshold, the LED is enabled to reduce glare when the light emitting element emits light luminance sufficient to be perceived as glare.

[0042] Luminance is measured in candela per square meter and can be considered as brightness. The area can be, for example, the area of ​​an enclosure or the projection of light emitted by a lighting device. Luminance can be measured in any number of ways known in the art as long as the luminance thresholds are calibrated relative to each other.

[0043] According to an embodiment of the invention, the minimum luminance threshold is proportional to the amount of flux emitted by the light emitting element.

[0044] Thus, the greater the amount of flux emitted by the light emitting element, the greater the glare reduction effect of the LED is enhanced.

[0045] According to an embodiment of the present invention, the LED and the light emitting element have the same correlated color temperature.

[0046] By having the light emitting elements and the LEDs have the same correlated color temperature, the aesthetic perception of the lighting device can be enhanced.

[0047] According to an embodiment of the invention, the capsule is made of PMMA, glass or polycarbonate.

[0048] These materials have proven to be sufficiently translucent and have relatively low scattering properties, which enables light outcoupling over the entire area of ​​the envelope. The choice of thickness and material may be influenced by the choice of LED so that the desired light scattering properties are achieved.

[0049] According to an embodiment of the invention, the LED emits colored light.

[0050] The colored light may be, for example, RGB or non-white LED.

[0051] Other objects, features and advantages of the present invention will become apparent when studying the following detailed disclosure, the drawings and the appended claims.Those skilled in the art will realize that different features of the present invention can be combined to produce embodiments other than those described in the following. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] This and other aspects of the invention will now be described in more detail, with reference to the accompanying drawings showing one or more embodiments of the invention.

[0053] Figure 1 schematically shows a lighting device according to an exemplary embodiment of the present invention, and

[0054] Figure 2 A lighting device according to an exemplary embodiment of the invention is schematically shown. DETAILED DESCRIPTION

[0055] Figure 1 A lighting device 10 is schematically shown. Figure 1 and Figure 2 The lighting device 10 shown is a light bulb, however, other lighting devices are possible within the scope of the appended claims. For example, the lighting device 10 may be a light strip, and may be light source.

[0056] The lighting device 10 includes a light emitting element 11. Figure 1In the exemplary embodiment of the present invention, the light emitting element 11 is a light emitting diode (LED) filament, however, other light emitting elements are possible within the scope of the appended claims.

[0057] The lighting device 10 also includes a translucent capsule 20 surrounding the light emitting element 11. The capsule 20 can hermetically seal a volume of gas or vacuum surrounding the light emitting element 11. The translucent capsule 20 can mean that most of the light emitted by the light emitting element 11 will be transmitted, because even if the light is reflected (due to Fresnel reflection) or scattered (by internal scattering particles), the light has a second (or third, or fourth...) chance to pass through the capsule 20 at a different location. The translucent capsule 20 can mean that at least 70% of the light emitted by the light emitting element 11 will be transmitted through the capsule 20 on the first pass, or preferably, at least 85% of the light is transmitted through the capsule 20.

[0058] The envelope 20 is coated with a phosphor layer 22 .

[0059] Phosphor layer 22 partially absorbs and partially re-emits light emitted by light emitting element 11. This enables, for example, part of the light emitted by light emitting element 11 to be absorbed by phosphor layer 22 and re-emitted across phosphor layer 22. This increases the effective area of ​​light emitting element 11.

[0060] The phosphor layer 22 may cover the entire area of ​​the encapsulant 20 or cover at least 50% or at least 80% of the area of ​​the encapsulant 20 .

[0061] Phosphor layer 22 may be made of the same phosphor as the coating on light emitting element 11. Phosphor layer 22 may also be made of a different phosphor composition than the coating on light emitting element 11, which may result in a difference in color between the light emitted by light emitting element 11 and the light re-emitted by phosphor layer 22.

[0062] In general, it may be beneficial for aesthetic reasons or color uniformity considerations that the light re-emitted from the phosphor layer 22 has a white point as close as possible to the black body line of the light. The phosphor layer 22 may be configured to have a white point relatively close to the black body line of the light. In order to bring the white point of the entire device closer to the black body line, the coating of the light emitting element 11 may be adapted, for example, with reduced phosphor, in order to compensate for the effect of the phosphor layer 22.

[0063] Phosphor layer 22 may be configured to block (i.e. absorb and not re-emit) less than or equal to 30% or 20% or less than 10% or 5% of the visible light emitted by light emitting element 11. This means that the efficiency of lighting device 10 is not reduced by more than 30% due to glare reduction.

[0064] The thickness of the phosphor layer 22 is 0.05 mm to 1.0 mm, such as 0.1 mm or 0.3 mm. The thickness of the phosphor layer 22 may be different in different parts of the envelope 20. For example, the phosphor layer 22 may be thicker in areas where the light emitted from the light emitting element 11 does not reach as effectively as other areas. Further, the phosphor layer 22 may be thin or dense and may be deposited in any manner known in the art.

[0065] In one embodiment, the phosphor layer 22 is applied only to certain portions of the envelope 20 and may, for example, form a pattern. The pattern may thus be reproduced by the light emitted by the lighting device 10. The phosphor layer 22 may include a pattern of phosphor spots. These spots may be very small, such as less than 1 mm in diameter, and may not be visible to the naked eye.

[0066] Preferably, two different types of blue light sources are used. The light emitting element may be a phosphor converted LED with a centroid wavelength of 450nm and a yellow phosphor to generate white light. The light emitting element may be an LED filament. The LED arranged to be connected to the capsule may be a blue emitting LED with a centroid wavelength of 430nm. In the case where the capsule is provided with a blue light emitting phosphor, the light emitted by the lighting device will have a nice white appearance in the far field. The light emitting element will emit yellow-white light with a lower color temperature, for example, in the range of 1800K to 2200K, and this warm yellow light will be mixed with the light blue light from the capsule.

[0067] Figure 2 The phosphor layer 22 is shown coated on the inside of the encapsulant 20, however in other embodiments the phosphor layer 22 may be coated on the outside of the encapsulant 20, ie not facing the light emitting element 11. It is preferred to have the phosphor layer 22 coated on the inside of the encapsulant 20.

[0068] The phosphor may be an organic phosphor. This means that the phosphor layer 22 is non-scattering, which may improve aesthetics and efficiency compared to, for example, non-organic phosphors. Organic phosphors do not rely on (transition) metal ions for light emission, but rather on photoluminescence. The main components are therefore organic substances and phosphors, i.e. carbon, hydrogen, nitrogen and, for example, fluorine or other halogens. These components may form organometallic complexes and / or be incorporated into polymers such as PMMA or polyethylene terephthalate (PET).

[0069] Phosphor layer 22 may also include scattering particles that are different from the phosphor. If phosphor layer 22 is patterned, the scattering particles may have the same or different patterns. The scattering particles may change the color or hue of the light emitted by lighting device 10. Alternatively, phosphor layer 22 or a structure incorporating the phosphor may scatter light in a similar manner.

[0070] Phosphor layer 22 may include ground particles of a phosphor-doped polymer, such as PMMA or PET. Such ground particles may scatter light.

[0071] For aesthetic reasons, some lighting devices 10 are coated with, for example, amber. This is particularly common when the light emitting element 11 is a filament. The phosphor layer 22 can replace the need for other layers such as an amber layer. Thus, the phosphor layer 22 can be the only coating on the envelope 20 of the lighting device 10.

[0072] The light emitting element 11 may include a separately controllable ultraviolet (UV) light source. The phosphor layer 22 may then be configured to absorb the UV light and re-emit the UV light as visible light. The UV light may be, for example, within the UVA and / or UVB spectrum. The re-emitted light may be completely within the visible light spectrum. This property of the phosphor may be inherent to the phosphor.

[0073] This enables more specific control of the lighting device 10. For example, only non-visible UV light is emitted from the light emitting element 11, and the phosphor layer 22 (re)emits visible light, so that the envelope 20 is illuminated without the light emitting element 11 being seen to emit light.

[0074] Figure 2 Schematically shows the Figure 1 The lighting device in is similar to the lighting device 10. Figure 2 The lighting device 10 and Figure 1 The lighting device in FIG. 1 is different in that the lighting device 10 further includes an LED 12 .

[0075] The LED 12 is arranged in connection with the translucent envelope 20 so that the envelope 20 acts as a light guide for the LED 12. Figure 2 Thus, the light emitted by the LED 12 is guided into the envelope 20, which acts as a light guide to guide the light within the envelope 20.

[0076] Notice, Figure 2 The sharp edges of the capsule 20 shown in the inset are schematic only and in another embodiment these may be smooth.

[0077] LED 12 can be, for example, a group of LEDs or micro-LEDs or single-sided LED filaments. Additionally, since the flexible printed circuit (FPC) can be made translucent, LED 12 can be a double-sided LED filament, for example, when the flexible printed circuit (FPC) is used as a carrier for the filament.

[0078] The encapsulant 20 is made of a translucent material having relatively low scattering properties such that light from the LED 12 is coupled out of the encapsulant 20 along an area of ​​the encapsulant 20. Preferably, the material properties of the encapsulant 20 are selected such that light from the LED 12 is coupled out of the encapsulant 20 along the entire area of ​​the encapsulant 20. Alternatively, light from the LED 12 is coupled out of the encapsulant 20 along at least the total height of the encapsulant 20, where the height is measured perpendicular to the surface or plate where the socket connector of the lighting device 10 engages with the encapsulant 20.

[0079] Encapsule 20 may be configured to emit light such that at least 50% of the area of ​​encapsule 20 emits light with a luminance that differs less than 5 times the average luminance of encapsule 20. Encapsule 20 may be configured, for example, by selecting materials, shapes, and thicknesses that achieve this.

[0080] Further, the envelope 20 may be configured to emit light such that at least 50%, 70%, or 80% of the area of ​​the envelope 20 emits light having a luminance that differs by less than two, five, or ten times the average luminance of the envelope.

[0081] For example, the capsule 20 may be made of polymethyl methacrylate (PMMA), glass, or polycarbonate. The capsule 20 may also be made of silicone or polyurethane.

[0082] Note that near the LED 12, the encapsulant 20 may emit light having a luminance that is significantly higher than the luminance of other portions of the encapsulant 20. Thus, the encapsulant 20 may be configured to emit light when used as a light guide for the LED 12 such that at least 50% of the area of ​​the encapsulant, excluding the portion closest to the LED (such as within 1 cm), emits light having a luminance that differs by less than a factor of 5 from the average luminance of the encapsulant 20.

[0083] The thickness of the encapsulant 20 may be between 0.2 mm and 4 mm, preferably between 0.5 mm and 2 mm, such as 1 mm. The encapsulant 20 is preferably thicker than the LED 12 so that the encapsulant 20 effectively captures the emitted light when used as a light guide.

[0084] The LED 12 may be integrated with or arranged to be connected to a surface where a socket connector of the lighting device 10 engages with the enclosure 20 .

[0085] The LEDs 12 may be arranged in a circle (or any other shape, depending on the lighting device 10) along the entire edge of the enclosure 20 (e.g., the interface between the socket connector of the lighting device 10 and the enclosure 20). Alternatively, the LEDs 12 may be arranged at two to eight discrete points at the edge of the enclosure 20. The two to eight discrete points may be equally spaced along the edge of the enclosure 20.

[0086] The LED 12 is configured to emit light having a minimum luminance threshold when the light emitting element 11 emits light above a predetermined luminance threshold.

[0087] Thus, when the light emitting element 11 emits light above a predetermined luminance threshold, the LED 12 will affect the enclosure 20 to glare (more). This reduces the brightness contrast between the light emitting element 11 and its surrounding components and increases the effective area of ​​the light emitted by the lighting device 10. Thus, when the luminance emitted by the light emitting element 11 is sufficient to be perceived as glare, the LED 12 is enabled to reduce glare.

[0088] The minimum luminance threshold may be proportional to the amount of flux emitted by the light emitting element 11. Thus, as the light emitting element 11 becomes brighter, the envelope 20 acting as a light guide for the LED 12 may also become brighter, thereby ensuring a relatively constant brightness contrast between the light emitting element 11 and its surroundings.

[0089] For example, when the light emitting element 11 emits light in the range of 500 lm to 1000 lm, the LED 12 emits light in the range of 100 lm to 1000 lm. When the light emitting element 11 emits light in the range of 1000 lm to 2000 lm, the LED 12 emits light in the range of 500 lm to 2000 lm.

[0090] In general, the brightness of the light emitted from the LED 12 may be 1 / 2 to 1 / 20 of the brightness of the light emitted by the light emitting element 11. This means that if the surface area of ​​the package 20 is 10 to 20 times the surface area of ​​the light emitting element 11, the flux of the light emitted by the light emitting element 11 is about the same order of magnitude as the light emitted by the LED 12. This results in the luminance of the light emitted from the package 20 being about one order of magnitude lower than the luminance of the light emitted by the light emitting element 11 due to the use as a light guide for the LED 12.

[0091] When the luminance of LED 12 is tested as the output of enclosure 20 acting as a light guide, the luminance of LED 12 can be configured to always be equal to or lower than the luminance of light emitting element 11. This allows light emitting element 11 to remain visible, thereby maintaining a consistent visual appearance of lighting device 10 that might otherwise be blinding to the user.

[0092] If the flux of light emitted by LED 12 is higher than that of light emitting element 11, where the ratio is equal to the ratio of the size difference between light emitting element 11 and package 20 (when the angular emission profile is also taken into account since luminous flux is measured in lumens and candela is lumens per steradian angle), then the light emitted by light emitting element 11 and package 20 will have similar luminance levels.

[0093] Since the LEDs 12 emit light, this increases the total flux emitted by the lighting device 10 compared to a conventional lighting device having only the light emitting element 11. Thus, the presence of the LEDs 12 alone allows the light emitting area and source to be extended while maintaining the total flux, thereby reducing not only the glare from the light emitting element 11, but also the absolute glare of the lighting device 10.

[0094] The light emitting element 11 and the LED 12 may emit white light and / or colored light. The light emitting element 11 and the LED 12 may emit the same or different colors, hues, (related) color temperatures, brightness or intensities.

[0095] In one embodiment, the light emitting element 11 emits white light, while the LED 12 emits colored light, for example, a set of RGB LEDs. This has the effect of shifting the color point of the emitted light to have a lower color saturation in an easily controllable energy-saving manner. This may also result in a specific aesthetic appearance of the lighting device 10, which, for example, enhances the atmosphere created by the lighting device 10, which would not be possible without the specific features of the lighting device 10.

[0096] In one embodiment, the lighting device comprises a controller arranged to control the light emitting elements 11 and the LEDs 12 independently.

[0097] The light emitting element 11 and the LED 12 may be individually controllable. Controlling each of the light emitting element 11 and the LED 12 may include adjusting the color, brightness or intensity of the light emitting element 11 and / or the LED 12. This may include, for example, controlling the light emitting element 11 and the LED 12 via Wi-Fi or One or more control signals are sent from the lighting control system to the light emitting elements 11 and the LEDs 12 in a wired or wireless manner.

[0098] In one embodiment, the controller is arranged to maintain the overall color point output of the lighting device when the external light guide is turned on. This is achieved by increasing the brightness of the envelope when the filament is turned on or when the brightness of the filament is above a certain threshold. In this way, the brightness contrast is greatly reduced and the lighting device can be operated at a higher flux output without glare.

[0099] By increasing the brightness of the envelope, the overall color point of the lamp may drift away from the target. The controller can bring the color point back to its target value by tuning the color point of the LED filament or the color point of the light guide.

[0100] By individually calibrating the light contribution of the light emitting element (LED filament) and the LED (encapsule), the desired total flux and color output can be easily tuned. This correction depends on the relative flux of the light guide incandescent lamp relative to the flux from the external bulb.

[0101] As a result, the lamp will present a nice decorative effect without any possible color appearance in the surrounding area. This is especially important when other "white" lamps are shining in the same area.

[0102] In another embodiment, the controller is arranged to couple the light setting of the LED in dependence on the light setting of the light emitting element. This mode of the controller may be particularly interesting for unconnected systems, in which case it is easy to control two light sources independently, wherein a wide range of user interfaces can be used to control the two light sources. However, for unconnected systems, addressing both light sources using a single controller (typically a dimmer or a wall switch) is not simple. For the lighting device of the invention, an intelligent control approach is proposed. The light setting of the second light source depends on the setting of the first light source: for example, depending on the required flux output, only one light source is switched on or both light sources are switched on simultaneously.

[0103] Proposal: The light emitted from the two sources is coupled and controlled by the existing infrastructure in the user's home (i.e. a common dimmer or a common on / off switch). The dimmer or on / off signal will be converted in the lighting device into different light settings for the two light sources. Depending on the position of the dimmer, one or both light sources are turned on.

[0104] As an example, when a dimmer is used, at a low dimmer position, it only sets the flux for the LED filament (light emitting element). At a certain flux level: the LED filament no longer increases the flux, but the LED is turned on and increases the flux as the dimmer position increases. Alternatively, the dimmer position can control three stages:

[0105] - Light emitting element flux changes (increases) and LED is in off state. When the dimmer is in low position (eg below 25%), only low light levels are required and only the LED filament will respond to the dimmer signal and radiate flux relative to the dimmer position.

[0106] - Lighting element flux changes (increases) and LED flux also changes (increases). When the dimmer is in an intermediate position (e.g., between 25% and 75%), the light guide will also start to shine, and both the light guide source and the LED filament will increase the flux corresponding to the dimmer position.

[0107] - Lighting element flux is constant (above a certain value) and LED flux varies (up to a maximum level). When the dimmer is in a high position (e.g. above 75%), only the light guide will respond to the increased percentage %, the LED filament will remain at the same value as at the 75% setting).

[0108] By combining the phosphor layer 22 with the LEDs 12, glare from the light emitting elements 11 is reduced, the lighting device 10 can be made more energy efficient, and the manufacturer also has better control over aesthetic considerations of the lighting device 10, such as pattern and color selection or combination.

[0109] Those skilled in the art realize that the present invention is by no means limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

Claims

1. A lighting device (10), comprising: a light emitting element (11), and a translucent capsule (20) surrounding the light emitting element (11) and having a surface area at least three times larger than the light emitting area of ​​the light emitting element (11), an LED (12) arranged to be connected to the encapsulation (20) such that the encapsulation (20) acts as a light guide for the LED (12), The capsule (20) is coated with a phosphor layer (22) having a thickness of 0.05 mm to 1.0 mm, and the phosphor layer (22) is configured to block less than 30% of visible light emitted by the light emitting element (11).

2. The device (10) according to claim 1, wherein the phosphor is an organic phosphor.

3. The device (10) of claim 1 or 2, wherein the thickness of the phosphor layer (22) is different in different parts of the envelope (20).

4. The device (10) according to one of the preceding claims, wherein the phosphor layer (22) comprises scattering particles which are different from the phosphor.

5. The device (10) according to any one of the preceding claims, wherein the envelope (20) is coated only with the phosphor layer (22).

6. The device (10) according to any of the preceding claims, wherein the light emitting elements (11) comprise individually controllable UV light sources, and wherein the phosphor layer (22) is configured to absorb UV light and re-emit it as visible light.

7. The device (10) according to any one of the preceding claims, wherein the light emitting element (11) is an LED filament.

8. The device (10) according to any one of the preceding claims, wherein the phosphor layer (22) is patterned.

9. The device (10) according to any one of the preceding claims, wherein the phosphor layer (22) comprises ground particles of a polymer incorporating the phosphor.

10. The device (10) according to any of the preceding claims, wherein the lighting device comprises a controller arranged to control the light emitting elements 11 and the LEDs 12 independently.

11. The device (10) of claim 10, wherein the controller is a dimmer having three stages of dimmer positions arranged to control: - Dimmer is in low position: the light emitting element flux changes (increases) and the LED is in off state; - the dimmer is in an intermediate position: the light emitting element flux changes (increases) and the LED flux also changes (increases); - Dimmer in high position: the light emitting element flux is constant (above a certain value) and the LED flux varies (reaches a maximum level).

12. A device according to any of the preceding claims, wherein the capsule (20) is configured to, when used as a light guide for the LED (12), emit light such that a luminance of light emitted from at least 50% of an area of ​​the capsule (20) differs by less than five times from an average luminance of the capsule (20).

13. The device according to any of the preceding claims, wherein the LED (12) is configured to emit light having a minimum luminance threshold when the light emitting element (11) emits light above a predetermined luminance threshold.

14. The device (10) of claim 13, wherein the minimum luminance threshold is proportional to the amount of flux emitted by the light emitting element (11).

15. The device according to any of the preceding claims, wherein the enclosure (20) is made of PMMA, glass or polycarbonate.

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