Adjustable LED filament

By arranging LEDs of different colors and color temperatures on the LED incandescent filament and combining them with the design of transparent and light-scattering layers, the problem of uncontrollable color and color temperature of LED incandescent lamps is solved, achieving uniform light emission and improved aesthetic effects.

CN115210497BActive Publication Date: 2026-06-16SIGNIFY HOLDING BV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
SIGNIFY HOLDING BV
Filing Date
2021-02-26
Publication Date
2026-06-16

AI Technical Summary

⚠Technical Problem

Existing LED incandescent lamps lack color controllability and color temperature control, and the uneven distribution of light scattering particles and nanoparticles in the wavelength conversion layer affects the uniformity of color temperature distribution.

⚗Method used

Multiple LEDs of different colors and/or different color temperatures are arranged on a slender carrier, combined with a transparent or nearly transparent layer and a light scattering layer to form a mixing chamber to achieve omnidirectional and uniform light emission. The light mixing is optimized by adjusting the thickness and reflectivity of the transparent layer and the light scattering layer.

🎯Benefits of technology

This invention enables LED incandescent lamps with adjustable color and color temperature, featuring a uniform light emission appearance and improved light distribution, mimicking the aesthetic effects of traditional incandescent lamps.

✦ Generated by Eureka AI based on patent content.

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Abstract

The invention relates to a color and / or color temperature tunable LED filament (20, 22, 24) comprising an elongated carrier (220) comprising a first major surface (222) and a second major surface (224) arranged opposite the first major surface, a plurality of LEDs (210) arranged in at least one linear array on the first surface of the elongated carrier, wherein the plurality of LEDs comprises LEDs of different colors and / or different color temperatures, a first elongated transparent or substantially transparent layer (230) covering the plurality of LEDs on the first major surface and further at least partially covering the first major surface, and a first elongated light scattering layer (240) arranged at least partially covering the first transparent or substantially transparent layer.
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Claims

1. A color-adjustable and / or color-temperature-adjustable light-emitting diode (LED) filament (20, 22, 24), said LED filament comprising: An elongated carrier (220) includes a first main surface (222) and a second main surface (224) arranged opposite to the first main surface. Multiple LEDs (210) are arranged in at least one linear array on the first main surface of the elongated carrier, wherein the multiple LEDs include LEDs of different colors and / or different color temperatures. A first elongated transparent or substantially transparent layer (230) covers the plurality of LEDs on the first main surface and also at least partially covers the first main surface. A first elongated light-scattering layer (240) is arranged to at least partially cover the first elongated transparent or substantially transparent layer. The second main surface of the elongated carrier is at least partially covered by a second elongated light-scattering layer, and The first elongated light scattering layer has a higher reflectivity than the second elongated light scattering layer.

2. The LED filament (22, 24) according to claim 1, wherein the second main surface of the elongated carrier is at least partially covered by a second elongated transparent or substantially transparent layer (260) having a thickness (T2), and wherein the second elongated light scattering layer (250) is arranged to at least partially cover the second elongated transparent or substantially transparent layer.

3. The LED filament according to claim 1, wherein the elongated carrier is translucent.

4. The LED filament according to claim 3, wherein the elongated carrier is transparent.

5. The LED filament according to any one of claims 1-4, wherein the maximum distance (D) between the light output surface (215) of the plurality of LEDs and the first elongated light scattering layer (240) is in the range of 0.5 mm to 5 mm.

6. The LED filament according to claim 5, wherein the maximum distance (D) between the light output surface (215) of the plurality of LEDs and the first elongated light scattering layer (240) is in the range of 0.8 mm to 4 mm.

7. The LED filament according to claim 6, wherein the maximum distance (D) between the light output surface (215) of the plurality of LEDs and the first elongated light scattering layer (240) is in the range of 1 mm to 3 mm.

8. The LED filament according to any one of claims 1-4, The plurality of LEDs includes a green LED (214), a red LED (212), and a blue LED (216), wherein the plurality of LEDs are arranged in three parallel and individually addressable linear arrays, and wherein one of the three parallel linear arrays contains the green LED, another of the three parallel linear arrays contains the red LED, and the third of the three parallel linear arrays contains the blue LED; or The plurality of LEDs include green LEDs (214), red LEDs (212), and blue LEDs (216) arranged alternately in a single linear array, wherein the green LEDs provide a green channel, the red LEDs provide a red channel, the blue LEDs provide a blue channel, and wherein the green channel, the red channel, and the blue channel are individually addressable.

9. The LED filament according to any one of claims 1-4, wherein the plurality of LEDs comprises cool white LEDs (218) and warm white LEDs (219) arranged alternately in a single linear array, wherein the cool white LEDs provide a cool white channel, wherein the warm white LEDs provide a warm white channel, and wherein the cool white channel and the warm white channel are individually addressable.

10. The LED filament according to any one of claims 1-4, wherein the first elongated light scattering layer has a reflectivity in the range of 30% to 90%.

11. The LED filament of claim 9, wherein the first elongated light scattering layer has a reflectivity in the range of 50% to 90%.

12. The LED filament of claim 10, wherein the first elongated light scattering layer has a reflectivity in the range of 60% to 90%.

13. The LED filament according to any one of claims 1-4, wherein the first elongated light scattering layer has an angular gradient in reflectivity such that the reflectivity is highest in the portion (R8) of the first elongated light scattering layer that is substantially parallel to the first main surface of the elongated carrier.

14. The LED filament according to claim 2 or 3, wherein the second elongated light scattering layer has a reflectivity in the range of 8% to 35%.

15. The LED filament of claim 14, wherein the second elongated light scattering layer has a reflectivity in the range of 10% to 32%.

16. The LED filament of claim 15, wherein the second elongated light scattering layer has a reflectivity in the range of 12% to 30%.

17. The LED filament according to claim 1 or 2, wherein the first elongated light scattering layer and the second elongated light scattering layer form a single omnidirectional light scattering layer (280).

18. The LED filament according to claim 2, wherein the maximum distance (D) between the light output surface (215) of the plurality of LEDs and the first elongated light scattering layer (240) is in the range of 0.5 mm to 5 mm, and the maximum distance (D) is greater than the thickness (T2) of the second elongated transparent or substantially transparent layer.

19. The LED filament according to claim 1 or 2, wherein the maximum normal distance P1 from the first main surface of the elongated carrier to the outer surface of the first elongated light scattering layer is at least 1.5 times the maximum normal distance P2 from the second main surface of the elongated carrier to the outer surface of the second elongated light scattering layer.

20. A modified light bulb (100), comprising: At least one LED filament according to any one of claims 1-19, a transmissive enclosure (10) at least partially surrounding the LED filament, a controller (50) electrically connected to the at least one LED filament, and a connector (40) for electrically and mechanically connecting the bulb to a socket.