TW201403886A - White light emitting diode - Google Patents

Abstract

The present invention relates to a white light emitting diode comprising: a light emitting unit that emits light having a wavelength between 200 nm and 650 nm; a plurality of encapsulating resin layers covering the surface of the light emitting unit; and a plurality of packages disposed in the packages A layer of phosphor powder between the resin layers.

Description

White light emitting diode

The invention relates to a white light emitting diode, in particular to a white light emitting diode capable of real-time adjusting the phosphor powder content to achieve a target color temperature in a process by using a multi-layer packaging technology.

Since the 1960s, the advantages of low power consumption and long-lasting illumination of Light Emitting Diodes (LEDs) have gradually replaced the use of indicators or light sources for lighting or various electrical appliances in daily life. . What's more, the development of multi-color and high-brightness LEDs has been applied to large outdoor display billboards or traffic signs, indicating that they can be applied in a wide range of fields.

In recent years, due to the significant increase in the luminous efficiency of light-emitting diodes, white light-emitting diodes have replaced the trend of traditional white-light bulbs. Conventional white-light emitting diodes are usually produced by spraying or coating fluorescent powder. And the like is disposed on the LED body, and then encapsulating the wafer with the encapsulating resin, so that the phosphor powder can be excited by the light emitted by the wafer to emit light of a suitable wavelength, and then mixed into white light. The light-emitting diode manufactured by the fluorescent powder is directly exposed to the wafer, is easily heated to accelerate the deterioration of the fluorescent powder, and shortens the life of the product; and the other method is to mix the fluorescent powder in the encapsulating resin. Directly using such a phosphor-containing encapsulating resin to encapsulate a light-emitting diode wafer, the light-emitting diode produced in this manner seems to prevent the phosphor powder from directly contacting the diode wafer. Accelerate its degradation, but there is an inevitable increase in the amount of phosphor powder used, resulting in unnecessary waste. In addition, the above two conventional methods of fabricating white light emitting diodes inevitably require curing of the encapsulating resin to know whether the color temperature of the product reaches its target. If the batch does not reach its target color temperature, only It can be recycled in batches, which is a big obstacle to the improvement of product yield.

Therefore, in order to improve the quality of the product of the light-emitting diode, to avoid the accelerated deterioration of the phosphor powder due to heat, the life of the product is shortened, thereby improving the yield of the product, reducing the waste of unnecessary raw materials, and developing a new way of manufacturing the light-emitting diode. It is necessary.

The main object of the present invention is to provide a white light emitting diode which can prevent the phosphor powder from directly contacting the light emitting diode wafer, thereby causing the fluorescent powder to be heated and accelerated to deteriorate, thereby shortening the life of the product; The required amount of phosphor powder is to prevent the color temperature analysis of the finished product from failing to reach the target color temperature to form a defective product, thereby reducing waste of unnecessary raw materials and improving product yield.

In order to achieve the above object, an aspect of the present invention provides a white light emitting diode comprising: a light emitting unit that emits light having a wavelength between 200 nm and 650 nm; and a plurality of encapsulating resin layers covering the surface of the light emitting unit; And a plurality of phosphor layers disposed between the encapsulating resin layers.

In the white light emitting diode of the present invention, the encapsulating resin layer comprises: a first resin layer covering the surface of the light emitting unit; a second resin layer on a surface of the resin layer; and a third resin layer covering the surface of the second resin layer, wherein a refractive index of the first resin layer may be higher than or equal to a refractive index of the second resin layer, The refractive index of the second resin layer may be higher than or equal to the refractive index of the third resin layer.

In the above white light emitting diode of the present invention, the refractive index of the first resin layer may be between 1.4 and 1.9, and the refractive index of the third resin layer may be between 1.0 and 1.3; in addition, the packages The composition of the resin layer may be a thermosetting resin or a photocurable resin containing an epoxy resin, a silicone resin, an acrylic resin or a combination thereof.

In the white light emitting diode of the present invention, the phosphor layer includes a first phosphor layer and a second phosphor layer, wherein the first phosphor layer is disposed on the first resin layer. And the second phosphor layer is disposed between the second resin layer and the third resin layer; the composition of the phosphor powder layer may include a red phosphor powder, Green fluorescent powder, a blue fluorescent powder, a yellow fluorescent powder or a combination thereof, wherein the red fluorescent powder may be selected from Ca ₂ SiN ₈ :Eu ²⁺ , Sr ₂ SiN ₈ :Eu ²⁺ , CaAlSiN ₃ :Eu ²⁺ , CaS:Eu ²⁺ , Y ₂ O ₃ :Eu ³⁺ , Y ₂ O ₃ :Bi ³⁺ , (Y,Gd) ₂ O ₃ :Eu ³⁺ , (Y,Gd) ₂ O ₃ a group consisting of Bi ³⁺ , Y ₂ O ₂ S:Bi ³⁺ , (Me _1-x Eu _x )ReS, Mg ₂ TiO ₄ :Mn ⁴⁺ , and Mg ₃ SiO ₄ :Mn; The phosphor powder may be selected from (Ba, Sr)SiO ₄ :Eu ²⁺ , Lu ₃ Al ₅ O ₁₂ :Ce ³⁺ , YBO ₃ :Ce ³⁺ , YBO ₃ :TB ³⁺ , SrGa ₂ S ₄ :Eu ^{2 +} , SrGa ₂ O ₄ :Eu ²⁺ , SrSi ₂ N ₂ O ₂ :Eu ²⁺ , SrAl ₂ O ₄ :Eu ²⁺ , (Ba,Sr)MgAl ₁₀ O ₁₇ :Eu ²⁺ and (Ba,Sr) MgAl ₁₀ O ₁₇ : Mn ^a group consisting of ²⁺ ; the blue fluorescent powder may be selected from BaMgAl ₁₀ O ₁₇ :Eu ²⁺ and (Ca,Sr,Ba) ₅ (PO ₄ ) ₃ Cl:Eu ²⁺ , Gd ²⁺ a group; and the yellow phosphor may be Y ₃ Al ₅ O ₁₂ :Ce ³⁺ , Tb ₃ Al ₅ O ₁₂ :Ce ³⁺ , CaSi ₂ N ₂ O ₂ :Eu ²⁺ , (Y,Cd) ₃ Al ₅ O ₁₂ :Ce ³⁺ , or (Me _1-xy Eu _x Re _y ) ₃ SiO ₅ , the above Me may be selected from Ca, Sr, Ba and combinations thereof; Re may be selected from Pr, Sm, Rb, Dy, Ho, Y, Er, Eu, Tm, Yb, Cr, Sr, Lu, Gd, Al, Zn, and combinations thereof.

In the above-mentioned white light emitting diode of the present invention, the encapsulating resin layer and the phosphor powder layers may have a multi-layer structure of 2 to 10 layers, wherein the phosphor layers may be continuously distributed or non- Continuously distributed, and the phosphor layers may be in a multi-layered shell pattern; in the foregoing invention, the multi-layer structure may be circular, rectangular, trapezoidal, triangular or a combination thereof, and the phosphor layers may be The pattern of concentric circles is arranged between the encapsulating resin layers, but the invention should not be limited thereto.

In the white light emitting diode of the present invention, the light emitting unit may comprise one or more light emitting diode chips having different wavelengths of light, preferably 2 to 16 light emitting diodes having different wavelengths of light. In the white light emitting diode of the present invention, the encapsulating resin layer and the phosphor powder layer may be formed in various conventional manners, such as spraying or coating, but the invention is not limited. herein.

In addition, another object of the present invention is to provide a chip on board (COB) in which the above-described light emitting diode package structure of the present invention is applied to the wafer board, thereby encapsulating the wafer board. The structure can instantly adjust the required amount of phosphor powder, so as to prevent the product from forming a defect due to the color temperature analysis of the package that does not reach the target color temperature, thereby reducing waste of unnecessary raw materials and thereby improving product yield.

In order to achieve the above object, another aspect of the present invention provides a chip on board (COB) including: a circuit carrier board; and the above-described white light emitting diode of the present invention, which comprises a composition A metal solder layer of gold or gold tin may be packaged on the circuit carrier.

In the above wafer-on-package structure of the present invention, the circuit carrier includes an insulating layer and a circuit substrate, wherein the insulating layer is made of insulating diamond-like carbon, aluminum oxide, ceramic, and diamond-containing epoxy. The resin, or a composition thereof, or a metal material having a surface covered with the insulating layer, and the circuit substrate may be a metal plate, a ceramic plate or a substrate. In addition, the surface of the circuit carrier can also optionally include a type of drilled carbon layer to increase the heat dissipation effect.

The embodiments of the present invention are described by way of specific examples, and those skilled in the art can readily appreciate the other advantages and advantages of the present invention. The present invention may be embodied or applied in various other specific embodiments, and various modifications and changes can be made without departing from the spirit and scope of the invention.

The drawings in the embodiments of the present invention are simplified schematic diagrams. However, the illustrations only show the components related to the present invention, and the components shown therein are not in actual implementation, and the actual number of components in the actual implementation is a selective design, and the component layout type. The state may be more complicated.

1A to 1F are schematic structural diagrams of a method for fabricating a white light emitting diode according to a first embodiment of the present invention; as shown in FIG. 1A, a substrate 4 is first prepared, and a light emitting unit 3 is disposed on the substrate 4; The light-emitting unit 3 covers a semi-spherical first resin layer 11 and heat-hardens the first resin layer 11 to a semi-cured state. In the present embodiment, a heat-cured epoxy resin having a refractive index of 1.5 is used. As the first resin layer 11, the light-emitting unit 3 is composed of a light-emitting diode wafer having two different wavelengths of light, and the light-emitting unit 3 can emit light having a wavelength of 450 nm to 500 nm, as shown in FIG. 1B. Show.

Thereafter, a red phosphor is coated on the upper surface 11a of the first resin layer 11 in a semi-cured state to form a continuous distribution of the first phosphor layer 21, as shown in FIG. 1C; and then, the first The phosphor layer 21 is coated with a second resin layer 12 and the second resin layer 12 is heat-hardened to a semi-cured state, as shown in FIG. 1D, wherein in the present embodiment, a heat having a refractive index of 1.4 is used. The cured epoxy resin is used as the second resin layer 12; at this time, the semi-finished product of the white light emitting diode can be subjected to color temperature analysis, and if the desired target color temperature is not reached, the upper surface 12a of the second resin layer 12 is coated. The yellow phosphor powder forms a continuous distribution of the second phosphor layer 22, as shown in FIG. 1E; after drying, a third resin layer 13 is coated and hardened to a semi-cured state, as shown in FIG. 1F, wherein, in this embodiment In the example, a thermosetting epoxy resin having a refractive index of 1.3 is used as the third resin layer 13; at this time, the white light emitting diode 100 can be subjected to color temperature analysis, and if the desired target color temperature is reached, the light is covered. The first resin layer 11, the second resin layer 12, and the third resin layer 13 on the surface of the unit 3 Thermally cured to complete molding, and complete the package; white light emitting diode in the present invention, the cover The resin layer on the surface of the light-emitting unit 3 (for example, the first resin layer 11, the second resin layer 12, and the third resin layer 13) may be arbitrarily adjusted to the number of laminated layers of the resin layer, and the hardening method (photocurable resin or thermosetting resin) And the refractive index, in addition, the phosphor layer (for example, the first phosphor layer 21, the second phosphor layer 22) may optionally adjust the number of layers or components of the phosphor layer, and may also Fluorescent powders of different light colors are disposed in different phosphor layers, or phosphors of different light colors are mixed and disposed in the same phosphor layer. Further, the phosphor layer may be continuous or between different resin layers. The distribution is discontinuous, and the invention is not limited thereto.

2A to 2F are schematic structural diagrams of a method for fabricating a white light emitting diode according to a second embodiment of the present invention, except that the composition of the phosphor layer or the resin layer is slightly changed, the packaging process of the embodiment and The structure is substantially the same as that of the first embodiment.

Referring to FIG. 2A, a substrate 4 is first prepared, and the substrate 4 is provided with a light-emitting unit 3; then, the light-emitting unit 3 is covered with a semi-spherical first resin layer 11 as shown in FIG. 2B, wherein, in this embodiment A photocurable epoxy resin having a refractive index of 1.4 is used as the first resin layer 11; after the ultraviolet light is irradiated to the semi-cured state, a phosphor powder is coated on the upper surface 11a of the first resin layer 11 to form a a non-continuously distributed first phosphor layer 21', as shown in FIG. 2C, wherein in the embodiment, the first phosphor powder layer 21' is formed by mixing green phosphor powder and yellow phosphor powder; After the phosphor layer 21' is dried, a second resin layer 12 is coated on the first phosphor layer 21' and irradiated with ultraviolet rays to a semi-cured state, as shown in FIG. 2D, wherein, in this embodiment, A photocurable epoxy resin having the same composition as the first resin layer 11 is used as the second resin Layer 12; at this time, the semi-finished product of the white light emitting diode can be subjected to color temperature analysis, and if the desired target color temperature is not reached, another red phosphor powder is coated on the upper surface 12a of the second resin layer 12 to form a non-continuous distribution of the second phosphor layer 22', as shown in FIG. 2E; after drying, a third resin layer 13 is coated and dried, as shown in FIG. 2F, wherein in the present embodiment, the refractive index is The light-curing epoxy resin of 1.3 is used as the third resin layer 13; at this time, the white light-emitting diode 200 can be subjected to color temperature analysis, and if the desired target color temperature is reached, the first resin layer covering the surface of the light-emitting unit 3 is further disposed. 11. The second resin layer 12 and the third resin layer 13 are irradiated with ultraviolet rays until they are completely cured, and the package is completed.

The technical feature of the present invention is to provide a technology for instantly adjusting the amount of phosphor powder required in the encapsulating resin, and to prevent the prepared white light emitting diode from failing to reach the target color temperature due to excessive or insufficient phosphor content. The problem of forming a defective product is generated. Therefore, in addition to the white light emitting diode of the three-layer resin package disclosed in the foregoing embodiment, if necessary, the process of spraying the phosphor powder layer and encapsulating the resin may be repeated until the product reaches the target color temperature. Therefore, please refer to FIG. 3, which is a schematic diagram of a white light emitting diode according to a third embodiment of the present invention. This embodiment is a four-layer resin-packed white light emitting diode.

Please refer to FIG. 3, and refer to the flow of the foregoing first embodiment, wherein after the white light emitting diode 100 of the present invention is completed (as shown in FIG. 1F), if the color temperature analysis is performed and the target color temperature is not reached, Applying a blue phosphor powder to the upper surface 13a of the third resin layer 13 to be dried to form a continuous distribution of the third phosphor layer 23, and then coating a fourth resin layer 14 and drying it to be dried. After the color temperature analysis, it is confirmed whether the white light emitting diode 300 reaches a target color temperature, wherein, in the present embodiment, a thermosetting epoxy resin having a refractive index of 1.2 is used as the fourth resin layer 14; as in the white light emitting diode of the present invention, if the target color temperature is reached, the cured resin is obtained. The package, if the target color temperature is not reached, repeat the above packaging process, and increase the number of stacked layers of the phosphor powder and the resin layer until the product reaches the target color temperature.

Please refer to FIG. 4, which is a schematic diagram of a white light emitting diode according to a fourth embodiment of the present invention, and refer to the flow of the foregoing second embodiment, wherein after the white light emitting diode 200 of the present invention is completed (FIG. 2F), If the color temperature analysis is performed, if the target color temperature is not reached, a green phosphor may be coated on the upper surface 13a of the third resin layer 13 to be dried to form a discontinuously distributed third phosphor layer 23'. Then, a fourth resin layer 14 is overcoated and dried. After drying, color temperature analysis is performed to confirm whether the white light emitting diode 400 reaches the target color temperature. In the present embodiment, the refractive index is 1.2. The photocurable epoxy resin is used as the fourth resin layer 14; if the white light emitting diode of the present invention has reached the target color temperature, that is, the cured resin package, if the target color temperature is not reached, the above packaging process is repeated, and the fluorescent process is added. The number of layers of powder and resin layers is stacked until the product reaches the target color temperature.

Please refer to FIG. 5 , which is a schematic structural diagram of a package structure on a wafer board according to a first embodiment of the present invention, wherein the package structure on the wafer board includes: a circuit carrier 5; and the white light illumination obtained by the first embodiment. The circuit board 5 is electrically connected to the circuit carrier 5 via a metal solder layer 6. The circuit board 5 includes an insulating layer 51 and a circuit substrate 52. The material of the insulating layer 51 can be selected as a free type. Drilling carbon, alumina, ceramics, diamond-containing rings An oxygen resin or a mixture of the above materials, the circuit substrate 52 is a metal plate, a ceramic plate or a substrate.

According to the present invention, in the chip on board (COB) of the present invention, the above-mentioned light emitting diode package structure of the present invention is disposed on the wafer board, so that the package structure on the wafer board can be instantly adjusted. The required amount of phosphor powder is good for improving product yield. Moreover, the light-emitting diode suitable for use in the above-described wafer-on-package structure of the present invention is not limited to the white light-emitting diode obtained in the above first embodiment, and any white light-emitting diode according to the present invention may be used. .

It can be seen from the above that the white light emitting diode of the multi-layer package of the present invention has a structural design capable of instantly adjusting the content of the phosphor powder in the encapsulating resin, and can instantly adjust the phosphor powder according to the color temperature analysis result in the process of encapsulating the light emitting diode. The content, to avoid the color temperature analysis of the product after the completion of the package does not reach the target color temperature to form a defective product, thereby reducing the waste of unnecessary raw materials and improving the product yield.

The above embodiments are merely exemplified for convenience of description. The phosphor layers may be alternately used for continuous distribution and discontinuous distribution, such as the first phosphor layer being continuously distributed and the second phosphor layer being discontinuous. The present invention is not limited thereto, and the scope of the claims should be construed as being limited to the above embodiments.

100,200,300,400‧‧‧White light emitting diode

11‧‧‧First resin layer

12‧‧‧Second resin layer

13‧‧‧ third resin layer

14‧‧‧ Fourth resin layer

11a, 12a, 13a‧‧‧ upper surface

21, 21’ ‧ ‧ first fluorescent layer

22,22’‧‧‧second luminescent layer

23,23’‧‧‧ Third luminescent layer

3‧‧‧Lighting unit

4‧‧‧Substrate

5‧‧‧Circuit carrier board

51‧‧‧Insulation

52‧‧‧ circuit board

6‧‧‧Metal welding layer

1A to 1F are schematic flow charts showing a method of fabricating a white light emitting diode according to a first embodiment of the present invention.

2A to 2F are schematic structural diagrams showing a method of fabricating a white light emitting diode according to a second embodiment of the present invention.

3 is a schematic view of a white light emitting diode according to a third embodiment of the present invention.

4 is a schematic view of a white light emitting diode according to a fourth embodiment of the present invention.

Fig. 5 is a perspective view showing the package structure on the wafer board of the first embodiment of the present invention.

100‧‧‧White light emitting diode

5‧‧‧Circuit carrier board

51‧‧‧Insulation

52‧‧‧ circuit board

6‧‧‧Metal welding layer

Claims (20)

A white light emitting diode comprising: a light emitting unit emitting light having a wavelength between 200 nm and 650 nm; a plurality of encapsulating resin layers covering a surface of the light emitting unit; and a plurality of phosphor layers Between the encapsulating resin layers. The white light emitting diode of claim 1, wherein the encapsulating resin layer comprises a first resin layer covering the surface of the light emitting unit; and a second resin layer covering the first a surface of the resin layer; a third resin layer covering the surface of the second resin layer. The white light emitting diode according to claim 2, wherein the refractive index of the first resin layer is higher than or equal to the refractive index of the second resin layer, and the refractive index of the second resin layer is higher than Or equal to the refractive index of the third resin layer. The white light emitting diode according to claim 3, wherein the first lipid layer has a refractive index of 1.4 to 1.9. The white light emitting diode according to claim 3, wherein the third lipid layer has a refractive index of 1.0 to 1.3. The white light emitting diode according to claim 1, wherein the encapsulating resin layer is a thermosetting resin or a photocurable resin. The white light emitting diode according to claim 6, wherein the encapsulating resin layer is an epoxy resin, a silicone resin or an acrylic resin. The white light emitting diode of claim 1, wherein the phosphor layers comprise a first phosphor layer and a second phosphor layer. The white light emitting diode according to claim 8, wherein the first phosphor layer is disposed between the first resin layer and the second resin layer. The white light emitting diode according to claim 8, wherein the second phosphor layer is disposed between the second resin layer and the third resin layer. The white light emitting diode according to claim 1, wherein the phosphor layers are selected from the group consisting of a red fluorescent powder, a green fluorescent powder, a blue fluorescent powder, and a yellow fluorescent powder. Or a group of combinations thereof. The white light emitting diode according to claim 1, wherein the phosphor layers are a continuous distribution or a discontinuous distribution. The white light emitting diode according to claim 1, wherein the phosphor layers are arranged in a concentric pattern between the encapsulating resin layers. The white light emitting diode according to claim 1, wherein the encapsulating resin layer and the phosphor layer have a multilayer structure of 2 to 10 layers. The white light emitting diode according to claim 1, wherein the light emitting unit is composed of one or a plurality of light emitting diode chips having different wavelengths of light. The white light emitting diode according to claim 15, wherein the light emitting unit is composed of two to six light emitting diode chips having different wavelengths of light. A chip on board (COB), And a white light emitting diode according to any one of claims 1 to 16, which is packaged on the circuit carrier via a metal solder layer. The wafer-on-board package structure of claim 17, wherein the circuit carrier comprises an insulating layer and a circuit substrate, and the insulating layer is made of at least one material selected from the group consisting of diamond-like carbon, aluminum oxide, ceramics, and A group of diamond-containing epoxy resins. The package structure on a wafer board according to claim 17, wherein the circuit substrate is a metal plate, a ceramic plate or a substrate. The package structure on a wafer board according to claim 17, wherein the metal solder layer is gold or gold tin.