Light emitting device and manufacturing method thereof
A light-emitting device including at least one light-emitting unit, a wavelength conversion adhesive layer, and a reflective protecting element is provided. The light-emitting unit has an upper surface and a lower surface opposite to each other. The light-emitting unit includes two electrode pads, and the two electrode pads are located on the lower surface. The wavelength conversion adhesive layer is disposed on the upper surface. The wavelength conversion adhesive layer includes a low-concentration fluorescent layer and a high-concentration fluorescent layer. The high-concentration fluorescent layer is located between the low-concentration fluorescent layer and the light-emitting unit. The width of the high-concentration fluorescent layer is W H . The width of the low-concentration fluorescent layer is W L . The width of the light-emitting unit is W E . The light-emitting device further satisfies the following inequalities: W E <W L , W H <W L and 0.8<W H /W E ≤1.2. Furthermore, a manufacturing method of the light-emitting device is also provided.
1. A manufacturing method of a light-emitting device, comprising:
forming a wavelength conversion adhesive layer, wherein the wavelength conversion adhesive layer comprises a low-concentration fluorescent layer and a high-concentration fluorescent layer;
providing a plurality of light-emitting units;
forming a plurality of trenches in the wavelength conversion adhesive layer to define a plurality of bonding regions between the trenches, wherein in the bonding regions, a width of the high-concentration fluorescent adhesive layer is W H , a width of the low-concentration fluorescent adhesive layer is W L , a width of the light-emitting unit is WE, and the step further satisfies the following inequalities: W E <W L , W H <W L , and 0.8<W H / W E ≤1.2;
respectively bonding the light-emitting units to the high-concentration fluorescent adhesive layers in the bonding regions;
forming a reflective protecting element on the wavelength conversion adhesive layer and between the light-emitting units to completely fill the trenches, wherein the reflective protecting element exposes the electrode pads of the light-emitting units; and
performing a cutting process along the trenches to form a plurality of light-emitting devices.
2. The manufacturing method of the light-emitting device of claim 1 , wherein in the step of forming the trenches in the wavelength conversion adhesive layer further comprises:
removing a portion of the high-concentration fluorescent adhesive layer and a portion of the low-concentration fluorescent adhesive layer to form a plurality of first sub-trenches, wherein the first sub-trenches respectively form a plurality of first mesa portions in the bonding regions, and each of the first mesa portions further comprises a first portion of the high-concentration fluorescent adhesive layer and a first portion of the low-concentration fluorescent adhesive layer; and
removing a portion of the low-concentration fluorescent adhesive layer to form a plurality of second sub-trenches in the first sub-trenches, wherein the second sub-trenches respectively form a plurality of second mesa portions in the bonding regions, each of the second mesa portions further comprises a second portion of the low-concentration fluorescent adhesive layer, and the first portion of the low-concentration fluorescent adhesive layer and the second portion of the low-concentration fluorescent adhesive layer are connected to each other,
wherein the trench comprises the first sub-trench and the second sub-trench.
3. The manufacturing method of the light-emitting device of claim 1 , further comprising, before the step of respectively bonding the light-emitting units to the high-concentration fluorescent adhesive layers in the bonding regions:
respectively forming a plurality of translucent adhesive layers on the high-concentration fluorescent adhesive layers in the bonding regions.
4. The manufacturing method of the light-emitting device of claim 3 , wherein in the step of respectively bonding the light-emitting units to the high-concentration fluorescent adhesive layers in the bonding regions, the light-emitting units are respectively bonded to the high-concentration fluorescent adhesive layers via the translucent adhesive layers.
5. The manufacturing method of the light-emitting device of claim 1 , further comprising, after the step of forming the reflective protecting element on the wavelength conversion adhesive layer and between the light-emitting units to completely fill the trenches:
leaving the reflective protecting element to stand such that the reflective protecting element forms a concave surface recessed toward the wavelength conversion adhesive layer; and
curing the reflective protecting element.