Glare Reduction of Lighting Device

Abstract

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

Description

Technical Field

[0001] The present invention broadly relates to glare reduction. In particular, the present invention relates to lighting devices having glare reduction features.

Background Art

[0002] Home and workplace environments include a number of lighting devices for creating functional lighting, ambient lighting, mood lighting, accent lighting or task lighting. It is well known that people often require high lux levels for reading, working, or even for the well-being of the people. When lighting devices are used as such high luminous flux light sources that supply, for example, 800 lumens, these lighting devices can be very dazzling and uncomfortable to use, and the brightness of the light-emitting elements is too high to be directly viewed. Some lighting devices change the light-emitting elements to reduce glare, for example by increasing the effective area. However, such light-emitting elements are not always suitable for either practical or aesthetic reasons. Therefore, it would be desirable to reduce glare in another way.

Summary of the Invention

Problems to be Solved by the Invention

[0003] An object of the present invention is to provide a lighting device having reduced glare.

Means for Solving the Problems

[0004] The inventor has noticed that by coating the envelope of the lighting device with a layer of phosphor, it is possible to increase the effective area of the lighting device without affecting the light-emitting element, thereby reducing glare.

[0005] According to a first aspect of the present invention, the object is achieved by an illumination device having the features in the independent claims. Preferred embodiments are defined in the dependent claims.

[0006] Accordingly, according to a first aspect of the present invention, there is provided an illumination device having a light emitting element and a translucent envelope surrounding the light emitting element and having a surface area at least three times larger than the light emitting area of the light emitting element, wherein the envelope is coated with a layer of phosphor having a thickness of 0.05 to 1.0 mm, and the layer of phosphor is configured to block 30% or less, or 20% or less, of the visible light emitted by the light emitting element.

[0007] The layer of phosphor absorbs some of the light emitted by the light emitting element and re - emits the light (through electron relaxation photon emission). By coating the envelope with the phosphor, the envelope emits light along the surface area where the phosphor is coated, thereby further increasing the light emitted over a larger area of the envelope.

[0008] The envelope has a surface area at least three times larger, such as five times larger, or ten or twenty times larger than the light emitting area of the light emitting element.

[0009] Accordingly, the present invention is based on the idea of providing a layer of phosphor that absorbs the light emitted by the light emitting element and re - emits the light, thereby emitting light in a larger area, i.e., over the entire surface area of the envelope or at least 50 to 80% thereof. The surface area of the envelope may be ten to twenty times larger than the light emitting element, or even more than fifty times larger, depending on the type of the light emitting element and the envelope. Thereby, the effective area of the light emitting element is increased and glare is reduced.

[0010] The light-emitting element can be used to provide functional illumination. The light from the phosphor layer can give the illumination device a white or colorful glow. Thus, it can supply a low-glare and high luminous flux so as to enable functional light that meets the criteria for eye comfort or white light with an aesthetically pleasing color glow effect.

[0011] The light-emitting element may be an LED filament, a light guide LED, or a direct-emitting LED.

[0012] The illumination device may be, for example, a light bulb or a lighting fixture.

[0013] The envelope may be of any shape, such as a sphere, may be flat (in one or two directions), or may be curved.

[0014] The present invention may be advantageous in that the glare is reduced while the light-emitting element remains unchanged.

[0015] According to an embodiment of the present invention, the phosphor is an organic phosphor (as opposed to the phosphor of a normal LED).

[0016] Thereby, the main components of the phosphor layer are organic and phosphor, i.e., carbon, hydrogen, nitrogen and, for example, fluorine or any other halogen. A well-known group of materials is the so-called perylene diamide molecular group.

[0017] According to an embodiment of the present invention, the thickness of the phosphor layer is different in different parts of the envelope.

[0018] The different thicknesses can be used to selectively increase the re-emitted light in a specific part of the envelope, for example, in a part where light from the first and / or the LED does not reach.

[0019] According to an embodiment of the present invention, the phosphor layer has scattering particles different from the phosphor.

[0020] The scattering particles can change the color or hue of the light emitted by the lighting device.

[0021] According to an embodiment of the present invention, the envelope is coated only with the phosphor layer.

[0022] Some lighting devices are coated with, for example, amber for aesthetic effects, but 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. The phosphor layer can replace the need for other layers such as an amber layer, whereby the phosphor layer re-emits more than 75% or more than 85% of the absorbed light, thereby improving efficiency (whereby the loss can be partially due to the Stokes shift).

[0023] According to an embodiment of the present invention, the light-emitting element has a separately controllable ultraviolet (UV) light source, and the phosphor layer is configured to absorb the UV light and re-emit the UV light as visible light.

[0024] The UV light may be, for example, within the UVA and / or UVB light spectra. The re-emitted light can be completely within the visible light spectrum.

[0025] This may enable more specific control of the lighting device 10. For example, only non-visible UV light may be emitted from the light-emitting element, and the phosphor layer (re)-emits visible light to brighten the envelope without seeing the light-emitting element that emits light.

[0026] According to an embodiment of the present invention, the light-emitting element is an LED filament.

[0027] The LED filament can be perceived as particularly dazzling. Furthermore, this brings about a combination of the advantages of phosphorescence and the advantages of filament technology, resulting in a new category of retrofit lighting devices.

[0028] According to an embodiment of the present invention, the phosphor layer is patterned.

[0029] Thereby, the pattern can be reproduced by the light emitted by the lighting device. The phosphor layer may have a pattern of phosphor dots. The dots may be very small, such as having a diameter of less than 1 mm, and may not be visible to the naked eye.

[0030] According to an embodiment of the present invention, the phosphor layer has ground particles of a polymer incorporating the phosphor.

[0031] Such ground particles may scatter light and may be easy to manufacture.

[0032] According to an embodiment of the present invention, the lighting device further has an LED disposed by being connected to the envelope such that the envelope serves as an optical guide for the LED.

[0033] The light from the LED is coupled into the envelope, and the envelope is made of a translucent material having relatively low light scattering characteristics, giving the lighting device a white or colorful glow. In this way, it can supply low glare and high luminous flux so as to enable functional light that meets the criteria for eye comfort, or white light with an effect of good-looking colored glow.

[0034] The LED may be a direct-emitting LED or a set of mini-LEDs, or a single-sided emitting LED filament.

[0035] Furthermore, by using two light-emitting elements, each light-emitting element can emit fewer lumens to achieve the same luminous flux level and further reduce glare.

[0036] According to an embodiment of the present invention, the light-emitting element and the LED can be controlled separately.

[0037] Thereby, different lumens, colors and / or color temperatures can be set for each of the light-emitting element and the LED.

[0038] According to an embodiment of the present invention, when the envelope serves as a light guide for the LED, at least 50% of the area of the envelope is configured to emit light with a luminance that differs from the average luminance of the envelope by less than one-fifth.

[0039] Luminance is measured in candela per square meter and is perceived as brightness. The area may be, for example, the projection of the light emitted by the lighting device or the area of the envelope. Any known method for measuring luminance can be used to ensure that the luminance does not differ by more than one-fifth between the portion of the envelope and the average.

[0040] Thereby, the envelope emits light that is relatively uniformly distributed along the area of the envelope, thereby further increasing the effective area of the emitted light.

[0041] According to an embodiment of the present invention, the LED is configured to emit light at a minimum luminance threshold when the light-emitting element emits light exceeding a predetermined threshold of luminance.

[0042] By the LED emitting light at a minimum luminance threshold when the light-emitting element emits light exceeding a predetermined threshold of luminance, the LED can reduce glare when the light-emitting element emits light at a luminance such that it is perceived as dazzling.

[0043] Luminance is measured in candelas per square meter and is perceived as brightness. The region may be, for example, the projection of the light emitted by the lighting device or the region of the envelope. 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.

[0044] According to an embodiment of the present invention, the minimum luminance threshold is proportional to the amount of light flux emitted by the light emitting element.

[0045] Thereby, the greater the amount of light flux emitted by the light emitting element, the stronger the glare reduction effect of the LED.

[0046] According to an embodiment of the present invention, the LED and the light emitting element have the same correlated color temperature.

[0047] By having the same correlated color temperature for the light emitting element and the LED, the aesthetic perception of the lighting device may be enhanced.

[0048] According to an embodiment of the present invention, the envelope is made of PMMA, glass or polycarbonate.

[0049] These materials are sufficiently translucent and have been proven to have relatively low scattering properties, which allows for out-coupling of light across the region of the envelope. The choice of thickness and material to achieve ideal light scattering properties may be affected by the choice of LED.

[0050] According to an embodiment of the present invention, the LED emits colored light.

[0051] The colored light may be, for example, RGB or non-white LEDs.

[0052] Other objects, features, and advantages of the present invention will become apparent upon study of the following detailed disclosure, drawings, and appended claims. It will be understood by those skilled in the art that the different features of the present invention can be combined to create embodiments other than those described in the embodiments below.

Brief Description of the Drawings

[0053] Here, with reference to the accompanying drawings showing embodiments of the present invention, this and other aspects of the present invention will be described in more detail.

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0054] FIG. 1 schematically shows a lighting device 10. The lighting devices shown in FIGS. 1 and 2 are light bulbs, but other lighting devices are also possible within the scope of the appended claims. For example, the lighting device 10 may be a light strip or a HUE (registered trademark) light source.

[0055] The lighting device 10 has a light-emitting element 11. In the exemplary embodiment of FIG. 1, the light-emitting element 11 is a light-emitting diode (LED) filament, but other light-emitting elements are also possible within the scope of the appended claims.

[0056] The lighting device 10 further has a translucent envelope 20 surrounding the light-emitting element 11. The envelope 20 can seal a certain volume of gas or vacuum surrounding the light-emitting element 11. The fact that the envelope 20 is translucent can mean that most of the light emitted by the light-emitting element 11 is transmitted, since the light has a second (or third, or fourth, …) chance of passing through the envelope 20 at a different location even if the light is reflected (due to Fresnel reflection) or scattered (by internal scattering particles). The fact that the envelope 20 is translucent can mean that at least 70%, or preferably at least 85% of the light emitted by the light-emitting element 11 passes through the envelope 20 on the first pass.

[0057] The envelope 20 is coated with a layer 22 of phosphor.

[0058] The layer 22 of phosphor partially absorbs and partially re-emits the light emitted by the light-emitting element 11. This allows, for example, a part of the light emitted by the light-emitting element 11 to be absorbed by the layer 22 of phosphor and re-emitted across the entire layer 22 of phosphor. This increases the effective area of the light-emitting element 11.

[0059] The layer 22 of phosphor may cover the entire area of the envelope 20, or at least 50% or at least 80% of the area of the envelope 20.

[0060] The layer 22 of phosphor may be made of the same phosphor as the coating on the light-emitting element 11. The layer 22 of phosphor may further be made of a phosphor with a composition different from the coating on the light-emitting element 11, which can result in a difference in the color emitted by the light-emitting element 11 and the re-emitted light of the layer 22 of phosphor.

[0061] Generally, it can be beneficial for aesthetic reasons or color uniformity that the re-emitted light from the phosphor layer 22 has a white point as close as possible to the blackbody locus of light. The phosphor layer 22 can be configured to have a white point relatively close to the blackbody locus of light. To further bring the white point of the entire device closer to the blackbody locus, the coating of the light-emitting element 11 may be adapted to have, for example, less phosphor, for example, to compensate for the action of the phosphor layer 22.

[0062] The phosphor layer 22 can be configured to block (i.e., absorb without re-emitting) 30% or less, or 20% or less, or 10% or less, or less than 5% of the visible light emitted by the light-emitting element 11. This means that the efficiency of the lighting device 10 is not sacrificed by more than 30% for glare reduction.

[0063] The phosphor layer 22 has a thickness of 0.05 to 1.0 mm, such as 0.1 mm or 0.3 mm. The thickness of the phosphor layer 22 can vary in different parts of the envelope 20. For example, the phosphor layer 22 may be thicker in regions where the light emitted from the light-emitting element 11 does not reach as effectively as in other regions. Furthermore, the phosphor layer 22 may be diluted, may be compact, and may be deposited in any manner known in the art.

[0064] In certain embodiments, the phosphor layer 22 may be applied only to a particular portion of the envelope 20 and may form a pattern, for example. Thereby, the pattern may be reproduced by the light emitted by the lighting device 10. The phosphor layer 22 may have a pattern of phosphor dots. The dots may be very small, such as having a diameter of less than 1 mm, and may not be visible to the naked eye.

[0065] Preferably, two different types of blue light sources are used. The light emitting element may be a phosphor-converted LED having a yellow phosphor for generating white light and a center wavelength of 450 nm. The light emitting element may be an LED filament. The LED disposed connected to the envelope may be a blue light emitting LED having a center wavelength of 430 nm. In the case of an envelope provided with a blue light emitting phosphor, the light emitted by the lighting device has a beautiful white appearance in the far field. The light emitting element emits a more yellowish white light having a low color temperature, for example, in the range of 1800 to 2200 K, which is mixed with the bluish light from the envelope.

[0066] Figure 2 shows a phosphor layer 22 coating the inside of the envelope 20, but in other embodiments, the phosphor layer 22 may be coated on the outside of the envelope 20, i.e., the outside not facing the light emitting element 11. It is preferred to have a phosphor layer 22 coating the inside of the envelope 20.

[0067] The phosphor may be an organic phosphor. This means that the phosphor layer 22 is non-scattering, which can improve aesthetics and efficiency, for example, as compared to an inorganic phosphor. The organic phosphor does not depend on (transition) metal ions for its emission, but rather on photoluminescence. Thereby, the main components are organic and phosphor, i.e., carbon, hydrogen, nitrogen and, for example, fluorine or other halogens. These components may form an organometallic complex and / or may be incorporated into a polymer such as PMMA or polyethylene terephthalate (PET).

[0068] The phosphor layer 22 may further have scattering particles different from the phosphor. When the phosphor layer 22 is patterned, the scattering particles may have the same pattern or a different pattern. The scattering particles may change the color or hue of the light emitted by the lighting device 10. In other examples, the structure of the phosphor layer 22 or the structure incorporating the phosphor may scatter light in a similar manner.

[0069] The phosphor layer 22 may have crushed particles of a polymer such as PMMA or PET incorporating the phosphor. Such crushed particles may scatter light.

[0070] Some lighting devices 10 are coated, for example, with amber for aesthetic effect. This is particularly common when the light-emitting element 11 is a filament. The phosphor layer 22 may replace the need for other layers such as an amber layer. Thus, the phosphor layer 22 may be the only coating on the envelope 20 of the lighting device 10.

[0071] The light-emitting element 11 may have separately controllable ultraviolet (UV) light sources. In that case, the phosphor layer 22 may 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 light spectra. The re-emitted light may be entirely within the visible light spectrum. This property of the phosphor may be inherent to the phosphor.

[0072] 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, brightening the envelope 20 without the user seeing the light-emitting element 11 that emits light.

[0073] FIG. 2 schematically shows a lighting device 10 similar to the lighting device 10 in FIG. 1. The lighting device 10 in FIG. 2 differs from the lighting device 10 in FIG. 1 in that the lighting device 10 also includes an LED 12.

[0074] The LED 12 is connected and disposed to a translucent envelope 20 such that the envelope 20 serves as an optical guide for the LED 12. This arrangement is shown in the inset of FIG. 2. Thus, the light emitted by the LED 12 is directed into the envelope 20, and the envelope 20 serves as an optical guide for guiding the light within the envelope 20.

[0075] Note that the sharp edge portion of the envelope 20 shown in the inset of FIG. 2 is merely schematic and, in another embodiment, this may be smooth.

[0076] The LED 12 may be, for example, a set of LEDs or mini-LEDs, or a single-sided emitting LED filament.

[0077] Furthermore, the LED 12 may be, for example, a double-sided emitting LED filament, since when a flexible printed circuit (FPC) is used as a carrier for the filament, the FPC can be made semi-transparent.

[0078] The envelope 20 is made of a semi-transparent material with relatively low scattering properties, so that the light from the LED 12 is out-coupled from the envelope 20 along the region of the envelope 20. Preferably, the material properties of the envelope 20 are selected such that the light from the LED 12 is out-coupled from the envelope 20 along the entire region of the envelope 20. In other examples, the light from the LED 12 is out-coupled from the envelope 20 at least along the full height of the envelope 20, where the height is measured perpendicular to the surface or substrate where the socket connector of the lighting device 10 interfaces with the envelope 20.

[0079] The envelope 20 may be configured to emit light such that at least 50% of the region of the envelope 20 emits light with a luminance that differs from the average luminance of the envelope by less than one-fifth. The envelope 20 can be configured, for example, by selecting the material, shape, and thickness to achieve this.

[0080] Furthermore, the envelope 20 may be configured to emit light such that at least 50%, 70%, or 80% of the region of the envelope 20 emits light with a luminance that differs from the average luminance of the envelope by less than one-half or one-fifth or one-tenth.

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

[0082] It should be noted that near the LED 12, the envelope 20 may emit light with a significantly higher brightness than other parts of the envelope 20. Therefore, when the envelope 20 serves as a light guide for the LED 12, at least 50% of the area of the envelope that does not include the portion within 1 cm or the like, which is closest to the LED, emits light with a brightness that differs by less than one-fifth from the average brightness of the envelope 20.

[0083] The thickness of the envelope 20 may be between 0.2 mm and 4 mm, preferably between 0.5 mm and 2 mm, such as 1 mm. The envelope 20 is preferably thicker than the LED 12 so as to efficiently capture the light emitted when the envelope 20 serves as a light guide.

[0084] The LED 12 may be integrated with the surface where the socket connector of the lighting device 10 interfaces with the envelope 20, or may be disposed in connection with the surface.

[0085] The LED 12 may be configured as a circle along the entire edge of the envelope 20, for example, along the interface between the socket connector of the lighting device 10 and the envelope 20 (or any other shape depending on the lighting device 10). In other examples, the LED 12 may be disposed at two to eight discrete points at the edge of the envelope 20. The two to eight discrete points may be arranged at equal intervals along the edge of the envelope 20.

[0086] The LED 12 is configured to emit light at a minimum brightness threshold when the light emitting element 11 emits light exceeding a predetermined threshold of brightness.

[0087] When the light-emitting element 11 emits light exceeding a predetermined threshold of luminance, the LED 12 thereby affects the envelope 20 to (more) shine. This reduces the brightness contrast between the light-emitting element 11 and its surroundings and increases the effective area of the light emitted by the lighting device 10. Thereby, the LED 12 can reduce glare when the light-emitting element 11 emits luminance such that it is perceived as dazzling.

[0088] The minimum luminance threshold may be proportional to the amount of luminous flux emitted by the light-emitting element 11. Therefore, as the light-emitting element 11 becomes brighter, the envelope 20 that serves as a light guide for the LED 12 also becomes 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 to 1000 lm, the LED 12 emits light in the range of 100 to 1000 lm. When the light-emitting element 11 emits light in the range of 1000 to 2000 lm, the LED 12 emits light in the range of 500 to 2000 lm.

[0090] Generally, the light emitted from the LED 12 can be about one-half to one-twentieth as bright as the light emitted by the light-emitting element 11. This means that when the surface area of the envelope 20 is 10 to 20 times larger than that of the light-emitting element 11, the light emitted by the light-emitting element 11 is of approximately the same order of luminous flux as the light emitted by the LED 12. This results in the luminance of the light emitted from the envelope 20 being approximately one order of magnitude lower than the light emitted by the light-emitting element 11 as a result of the envelope 20 serving as a light guide for the LED 12.

[0091] The luminance of the LED 12, when measured as the output of the envelope 20 when it serves as an optical guide, can be configured to always be equal to or lower than the luminance of the light-emitting element 11. This enables the light-emitting element 11 to remain visible, thereby maintaining the consistency of the appearance of the lighting device 10, which could otherwise be unpleasant for the user.

[0092] When the LED 12 emits light with a luminous flux higher than that of the light-emitting element 11 at a ratio equal to the ratio of the size difference between the light-emitting element 11 and the envelope 20 (when also considering the angular emission profile, as the luminous flux is measured in lumens and the candela is lumens per steradian), the light emitted by the light-emitting element 11 and the envelope 20 has a similar level of luminance.

[0093] Since the LED 12 emits light, this increases the total luminous flux emitted by the lighting device 10 compared to a conventional lighting device having only the light-emitting element 11. Thus, simply by the presence of the LED 12, it becomes possible to expand the light-emitting area and the light source while maintaining the total luminous flux amount, 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, (correlated) color temperatures, brightnesses, or intensities.

[0095] In one embodiment, the light-emitting element 11 emits white light, and the LED 12, which is, for example, a set of RGB LEDs, emits colored light. This has the effect of shifting the color point of the emitted light to have a lower chroma in an energy-efficient and easy-to-control manner. This can further result in a specific aesthetic appearance of the lighting device 10 that enhances the atmosphere created by the lighting device 10 and is otherwise not possible without specific features of the lighting device 10.

[0096] In an embodiment, the lighting device has a controller configured to independently control the light emitting element 11 and the LED 12.

[0097] The light emitting element 11 and the LED 12 may be controllable separately. 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 transmitting a control signal from the lighting control system to the light emitting element 11 and the LED 12, either wired or wirelessly, for example via Wi-Fi or Bluetooth (registered trademark).

[0098] In an embodiment, the controller is configured to maintain the total color point output of the lighting device when the outer light guide is turned on. This is achieved by increasing the brightness of the envelope when the filament is switched on or when the brightness of the filament exceeds a certain threshold. In this way, the brightness contrast is significantly reduced and the lighting device can be operated with a higher luminous flux output without being dazzling.

[0099] By increasing the brightness of the envelope, the total color point of the lamp may deviate from the target. The controller may return the color point to its target value by adjusting the color point of the LED filament or the light guide.

[0100] By separately calibrating the contributions of the light emitting element (LED filament) and the light of the LED (envelope), the required total luminous flux and color output can be easily adjusted. This correction depends on the relative luminous flux of the light guide filament lamp with respect to the luminous flux coming from the outer bulb.

[0101] As a result, the lamp provides an excellent decorative effect without any visible possible colors in the surrounding area. This is particularly important when other "white" lamps are emitting light in the same area.

[0102] In a further embodiment, the controller is configured to couple the light settings of the LEDs depending on the light settings of the light emitting elements. This mode of the controller can be particularly interesting for unconnected systems. Controlling two light sources independently is easy in the case of a connected system where an extensive user interface can be used to control both light sources. However, in the case of an unconnected system, it is not easy to handle both light sources with a single control device (usually a dimmer or a wall switch). For the lighting device of the present invention, a smart way to control it is proposed. The light settings of the second light source depend on the settings of the first light source, and for example, depending on the required luminous flux output, only one or both light sources are switched on.

[0103] It is proposed that the light coming from the two light sources is coupled and controlled by the existing infrastructure in the consumer's home, i.e., a normal dimmer or a normal on / off switch. The dimmer signal or the on / off signal is converted into different light settings for the two light sources in the lighting device. Depending on the dimmer position, one or both light sources are switched on.

[0104] As an example when using a dimmer, at a low dimmer position, it sets only the luminous flux for the LED filament (light emitting element). At a certain luminous flux level, the LED filament does not increase the luminous flux any further, but the LED is switched on and the luminous flux increases as the dimmer position is raised. In other examples, the dimmer position can control three levels. - The luminous flux of the light emitting element changes (increases) and the LED is in the off state. When the dimmer is in a low position, for example, less than 25%, only a low light level is required and only the LED filament responds to the dimmer signal and emits a luminous flux related to the dimmer position. - The luminous flux of the light-emitting element changes (increases), and the luminous flux of the LED also changes (increases). When the dimmer is in an intermediate position (e.g., between 25% and 75%), the light guide also starts to glow, and both the light guide light source and the LED filament increase their luminous flux corresponding to the dimmer position. - The luminous flux of the light-emitting element is constant (above a certain value), and the luminous flux of the LED changes (up to the maximum level). When the dimmer is in a high position (e.g., above 75%), only the light guide responds to the % increase, and the LED filament remains at the same value (as at 75% setting).

[0105] By combining the phosphor layer 22 and the LED 12, both of which reduce the glare of the light-emitting element 11, the lighting device 10 may be more energy-efficient, and the manufacturer can further control the aesthetic considerations of the lighting device 10, such as pattern and color options or combinations.

[0106] Those skilled in the art will appreciate that the present invention is in no way limited to the above preferred embodiments. On the contrary, many modifications and changes are possible within the scope of the appended claims.

Claims

1. Light-emitting element, A translucent envelope surrounding the light-emitting element and having a surface area at least three times larger than the light-emitting region of the light-emitting element, A lighting device comprising an LED, wherein the LED is arranged connected to the envelope such that the envelope serves as a light guide for the LED, The envelope is coated with a phosphor layer having a thickness of 0.05 to 1.0 mm, and the phosphor layer is configured to block less than 30% of the visible light emitted by the light-emitting element. A lighting device configured such that when the light-emitting element emits light exceeding a predetermined luminance threshold, the LED emits light at a minimum luminance threshold, influencing the envelope to emit light, reducing the brightness contrast between the light-emitting element and the LED, thereby reducing glare.

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

3. The device according to claim 1 or 2, wherein the thickness of the phosphor layer is different in different parts of the envelope.

4. The device according to claim 1 or 2, wherein the phosphor layer has scattering particles different from the phosphor.

5. The device according to claim 1 or 2, wherein the envelope is coated only with the phosphor layer.

6. The device according to claim 1 or 2, wherein the light-emitting element has a UV light source that can be controlled separately, and the phosphor layer is configured to absorb UV light and re-emit the UV light as visible light.

7. The device according to claim 1 or 2, wherein the light-emitting element is an LED filament.

8. The device according to claim 1 or 2, wherein the phosphor layer is at least one of patterned or pulverized polymer particles incorporating the phosphor.

9. The light-emitting element has a yellow phosphor for generating white light and a phosphor conversion LED having a centroid wavelength of 450 nm, the LED has a blue light-emitting LED having a centroid wavelength of 430 nm, or the envelope is provided with a blue light-emitting phosphor. The device according to claim 1 or 2, wherein the light emitted by the illumination device has a beautiful white appearance in the far field of view.

10. The device according to claim 1 or 2, wherein the lighting device has a controller configured to independently control the light-emitting element and the LED.

11. The controller is a dimmer having dimmer positions configured to control three stages, When the dimmer is in a low position, the luminous flux of the light-emitting element changes (increases), and the LED is in the off state. When the dimmer is in the intermediate position, the luminous flux of the light-emitting element changes (increases), and the luminous flux of the LED also changes (increases). The device according to claim 10, wherein when the dimmer is in a high position, the luminous flux of the light-emitting element is constant (above a certain value) and the luminous flux of the LED changes (up to the maximum level).

12. The device according to claim 1 or 2, wherein when the envelope serves as a light guide for the LED, at least 50% of the area of ​​the envelope emits light at a brightness that differs from the average brightness of the envelope by less than one-fifth.

13. The device according to claim 1 or 2, wherein the LED is configured to emit light at a minimum brightness threshold when the light-emitting element emits light exceeding a predetermined brightness threshold.

14. The device according to claim 13, wherein the minimum brightness threshold is proportional to the amount of light flux emitted by the light-emitting element.

15. The device according to claim 1 or 2, wherein the envelope is made of PMMA, glass, or polycarbonate.

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