Light emitting diode filament including flip chip light emitting diodes to reduce the amount of phosphor that is integrated into the filament

Patent metadata

Field	Value
Publication number	US-12588335-B2
Application number	US-202117517158-A
Country	US
Kind code	B2
Filing date	Nov 2, 2021
Priority date	Nov 2, 2021
Publication date	Mar 24, 2026
Grant date	Mar 24, 2026

Abstract

A light emitting diode (LED) structure that includes a stent substrate; and a circuit having a plurality of contact pads arranged along a length of the stent substrate. The structure further includes a plurality of light emitting diode (LED) chips, wherein each light emitting diode chip in the plurality of chips is engaged to a set of contact pads along the length of the metal stent substrate. A continuous phosphor layer is present overlying the plurality of light emitting diode (LED) chips, the continuous phosphor layer including first portions that are in direct contact with at least a light transmission surface of the light emitting diode (LED) chips and second portions that bridge across the space separating adjacently positioned light emitting diode. An encapsulant present over the continuous phosphor layer that is covering at least the light emitting diode chips.

First claim

What is claimed is:

1 . A light emitting diode (LED) structure comprising:
a stent substrate; a circuit having a plurality of contact pads arranged along a length of the stent substrate; a plurality of light emitting diode (LED) chips, wherein each light emitting diode chip in the plurality of chips is engaged to a set of contact pads along the length of the metal stent substrate; a continuous phosphor layer overlying the plurality of light emitting diode (LED) chips, the continuous phosphor layer including first portions that are in direct contact with at least a light transmission surface of the light emitting diode (LED) chips and second portions that bridge across the space separating adjacently positioned light emitting diodes, wherein the space separating the adjacently positioned light emitting diodes includes an airgap having a width extending between sidewalls of the adjacently positioned light emitting diodes, the airgap having an upper surface defined by a lower surface of the second portions of the continuous phosphor layer that bridge across the space separating the adjacently positioned light emitting diodes; and an encapsulant present over the continuous phosphor layer that is covering at least the light emitting diode chips.

2 . The light emitting diode (LED) structure of claim 1 , wherein the plurality of light emitting diode (LED) chips comprise Flip Chip (FC) light emitting diodes (LEDS).

3 . The light emitting diode (LED) structure of claim 1 , wherein the encapsulant is transparent or translucent.

4 . The light emitting diode structure of claim 1 , wherein a length for the LED filament ranges from 3 mm to 30 mm, and a width for the LED filament ranges from 0.3 mm to 2.0 mm.

5 . The light emitting diode structure of claim 1 , wherein the light transmission surface that is in contact with the first portions of the continuous phosphor layer is an upper surface of the light emitting diode chip that is opposite a surface of the light emitting diode chip that is bonded to the stent substrate.

6 . The light emitting diode structure of claim 1 , wherein said each light emitting diode chip in the plurality of chips is engaged to the set of contact pads by solder bond.

7 . The light emitting diode structure of claim 1 , wherein a thickness for the continuous phosphor layer ranges from 150 microns to 500 microns.

8 . The light emitting diode structure of claim 1 , wherein the continuous phosphor layer is only present on a side of the stent substrate that the Light Emitting Diodes (LEDs) are also present on.

9 . A light emitting filament structure comprising:
a filament substrate; a plurality of flip chip light emitting diode (LED) chips; and a continuous phosphor layer overlying the plurality of the flip chip light emitting diode (LED) chips, the continuous phosphor layer includes first portions that are in direct contact with at least a light transmission surface on an upper surface of the flip chip light emitting diode (LED) chips, and second portions that bridge across the space separating adjacently positioned light emitting diodes of the plurality of flip chip light emitting diode (LED) chips, the space separating the adjacently positioned light emitting diodes has a width extending between exposed sidewalls of the adjacently positioned light emitting diodes, the exposed sidewalls of the adjacently positioned light emitting diodes are not in contact with the continuous phosphor layer, wherein the space separating the adjacently positioned light emitting diodes has an upper surface defined by a lower surface of the second portions of the continuous phosphor layer.

10 . The light emitting filament structure of claim 9 , wherein the filament substrate is comprised of a dielectric material or a metal selected from the group consisting of stainless steel, copper, brass, aluminum, aluminum alloy, tungsten and combinations thereof.

11 . The light emitting filament structure of claim 9 , further comprising an encapsulant on the continuous phosphor layer, wherein the encapsulant is transparent or translucent.

12 . The light emitting filament diode structure of claim 9 , wherein the plurality of flip chip light emitting diodes (LED) chips use a 385 nm to 480 nm light emitting semiconductor material structure.

13 . The light emitting filament structure of claim 9 , wherein the plurality of the flip chip light emitting diode (LED) chips comprise GaN (gallium nitride) light emitting diodes, indium gallium nitride (InGaN) light emitting diodes or a combination thereof.

14 . The light emitting filament structure of claim 9 , wherein the continuous phosphor layer has a composition including cerium doped yttrium aluminium garnet (YAG:Ce) crystals.

15 . The light emitting filament structure of claim 9 , wherein the continuous phosphor layer is only present on a side of the filament substrate that the plurality of flip chip light emitting diode (LED) chips are also present on.

16 . A method of assembling a filament light emitting diode comprising:
forming a circuit on a filament stent substrate, wherein the circuit having pads arranged along of length of the filament stent substrate; bonding light emitting diode (LED) chips to the circuit, the light emitting diode chips including a light emitting diode (LED) die having contacts on a contact surface side of the LED chips for the bonding to the pads of the circuit; and forming a continuous phosphor layer on the plurality of light emitting diodes, the phosphor layer includes first portions of the continuous phosphor layer that are in direct contact with at least a light transmission surface of the light emitting diode (LED) chips, and second portions of the continuous phosphor layer that bridge across the space separating adjacently positioned light emitting diodes, the second portions of the continuous phosphor layer encapsulating an air gap between the adjacently positioned light emitting diodes.

17 . The method of claim 16 , wherein the continuous phosphor layer is only present on a side of the filament stent substrate that the light emitting diode (LED) chips are also present on.

18 . The method of claim 16 further comprising forming a transparent encapsulant over at least the light emitting diode (LED) die.

19 . The method of claim 16 , wherein the bonding of the light emitting diode (LED) chips to the circuit comprises solder bonding.

20 . The method of claim 16 , wherein the continuous phosphor layer has a composition including cerium doped yttrium aluminium garnet (YAG:Ce) crystals.

Assignees

• Ledvance Llc

Inventors

• Wang Xinrong
• Jiang tianzheng
• Li Ming

Classifications

• H10W90/00 Primary

  Package configurations · CPC title

• H10H20/0364

  of interconnections · CPC title

• H10H20/0362

  of encapsulations · CPC title

• H10H20/8512

  Wavelength conversion materials · CPC title

• H10H20/854

  characterised by their material, e.g. epoxy or silicone resins · CPC title