CN109860367B

CN109860367B - Light emitting device

Info

Publication number: CN109860367B
Application number: CN201910108698.1A
Authority: CN
Inventors: 时军朋; 余长治; 徐宸科; 黄兆武; 黄永特
Original assignee: Quanzhou Sanan Semiconductor Technology Co Ltd
Current assignee: Quanzhou Sanan Semiconductor Technology Co Ltd
Priority date: 2019-02-03
Filing date: 2019-02-03
Publication date: 2020-04-21
Anticipated expiration: 2039-02-03
Also published as: WO2020155532A1; CN109860367A

Abstract

The invention discloses a light emitting device. In some embodiments, the light emitting device comprises: a support having a mounting surface for mounting an LED chip; more than two LED chips mounted on the mounting surface of the bracket; the packaging material layer covers the surface of the LED chip and seals the LED chip on the support; the LED chip comprises a first electrode, a second electrode and a reflecting layer, wherein the light-emitting angle of the LED chip is less than or equal to 120 degrees, the upper surface of the LED chip is a light-emitting surface, the LED chip comprises the first electrode, the second electrode and the reflecting layer, the first electrode and the second electrode face upwards, and the distance between the reflecting layer and the light-emitting surface is less than 10 micrometers.

Description

Light emitting device

Technical Field

The invention relates to the field of semiconductor devices, in particular to a light-emitting device.

Background

Light emitting diodes are widely used as solid state lighting sources. Compared with the traditional incandescent bulb and fluorescent lamp, the light emitting diode has the advantages of low power consumption, long service life and the like, so the light emitting diode gradually replaces the traditional light source and is applied to various fields such as traffic signs, backlight modules, street lamp illumination, medical equipment and the like.

Disclosure of Invention

The present invention provides a light emitting device including: a support having a mounting surface for mounting an LED chip; more than two LED chips mounted on the mounting surface of the bracket; the packaging material layer covers the surface of the LED chip and seals the LED chip on the support; the LED chip comprises a first electrode, a second electrode and a reflecting layer, wherein the light-emitting angle of the LED chip is less than or equal to 120 degrees, the upper surface of the LED chip is a light-emitting surface, the LED chip comprises the first electrode, the second electrode and the reflecting layer, the first electrode and the second electrode face upwards, and the distance between the reflecting layer and the light-emitting surface is less than 10 micrometers.

Preferably, defining OL as the overlapping length of two adjacent LED chips, P as the perimeter of the LED chip, T as the thickness of the chip, G as the spacing between the adjacent LED chips, and R as the light blocking coefficient, then R = (OL/P) × (T/G) ≧ 0.2. In some embodiments, R is preferably in the range of 0.2 to 2.

Preferably, the distance between the reflecting layer and the light-emitting surface is 4-8 μm.

In some embodiments, the LED chip includes a substrate, an epitaxial stack, a first electrode and a second electrode, the first electrode and the second electrode being respectively LED out from a lower surface of the epitaxial stack through a conductive layer and toward an upper surface of the epitaxial stack.

In some embodiments, the LED chip includes a substrate, and an epitaxial stack, a first electrode and a second electrode over the substrate, the first and second electrodes being located outside the epitaxial stack.

Further, the support is provided with a first welding line area and a second welding line area, the first welding line area and the second welding line area are electrically isolated from each other, and the first electrode and the second electrode are respectively connected to the first welding line area and the second welding line area of the support through leads.

In some embodiments, the epitaxial stack layer is removed from the growth substrate, the upper surface of the epitaxial stack layer is a light emergent surface, and the epitaxial stack layer sequentially comprises a first semiconductor layer, an active layer and a second semiconductor layer from bottom to top.

In some embodiments, the LED chip may further include a first electrical connection layer electrically connecting the first semiconductor layer and the first electrode, and a second electrical connection layer electrically connecting the second semiconductor layer and the second electrode.

Furthermore, the light emitting device may further include a third electrical connection layer, which is located below the first and second electrical connection layers, and has at least one first extension portion and one second extension portion, wherein the first extension portion penetrates through the first semiconductor layer and the active layer and contacts the second semiconductor layer, and the second extension portion contacts the second electrical connection layer.

Preferably, the third electrical connection layer comprises a second reflective layer and a bonding layer.

In some embodiments, the third electrical connection layer and the substrate form a heat dissipation channel for guiding heat accumulated in the second semiconductor layer to the support and guiding the heat out when the light emitting device is in operation.

Preferably, the distance between the LED chips is less than or equal to 150 μm. In some embodiments, the distance between the LED chips is 50-120 μm.

In some embodiments, the upper surface of the LED chip is a light emitting surface, and includes, from top to bottom, an epitaxial stack, a first reflective layer, a second reflective layer, and a substrate.

Preferably, the epitaxial stack includes a first semiconductor layer, an active layer, and a second semiconductor layer, and the reflective layer is spaced from the active layer by a distance of 1 μm or less.

It is preferred. The distance between the second reflecting layer and the light emergent surface is less than 20 μm.

Further, a third reflection may be disposed between the substrate and the support.

In some embodiments, the substrate is transparent to light emitted by the epitaxial stack.

In some embodiments, the substrate is a highly reflective substrate, which is more than 90% reflective.

In some embodiments, the light emitting device further includes a light conversion layer located on a plane where the light emitting surface of the LED chip is located.

In some embodiments, the light emitting device comprises at least three LED chips, each LED chip emitting in a different spectrum.

In some embodiments, the light emitting device comprises four LED chips, wherein a light emitting surface of one LED chip is coated with a fluorescent layer.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. Furthermore, the drawing figures are for a descriptive summary and are not drawn to scale.

Fig. 1 is a schematic diagram illustrating a structure of a conventional light emitting diode package.

Fig. 2 is a schematic diagram illustrating a structure of a conventional led package.

Fig. 3 is a schematic diagram illustrating a light emitting device according to some examples of the invention.

Fig. 4 is a schematic diagram illustrating an LED chip structure of a light emitting device of some embodiments.

Fig. 5 is a schematic diagram illustrating an LED chip structure of a light emitting device of some embodiments.

Fig. 6 is a schematic diagram illustrating an LED chip structure of a light emitting device of some embodiments.

Fig. 7 is a schematic diagram illustrating a light emitting device according to some examples of the invention.

Fig. 8 is a schematic view illustrating a part of a light path of the light emitting device shown in fig. 7.

Fig. 9 is a schematic diagram illustrating a light emitting device according to some examples of the invention.

Fig. 10 is a schematic diagram illustrating an LED chip structure of a light emitting device of some embodiments.

Fig. 11 is a schematic diagram illustrating a light emitting device according to some examples of the invention.

Fig. 12 is a schematic diagram illustrating an LED chip structure of a light emitting device of some embodiments.

Fig. 13 is a schematic diagram illustrating an LED chip structure of a light emitting device of some embodiments.

Fig. 14 is a schematic diagram illustrating a light emitting device according to some examples of the invention.

Fig. 15 is a schematic diagram illustrating a light emitting device according to some examples of the invention.

Fig. 16 is a schematic diagram illustrating an LED chip structure of a light emitting device of some embodiments.

Fig. 17 is a schematic diagram illustrating a light emitting device according to some examples of the invention.

Fig. 18 is a schematic diagram illustrating a light emitting device according to some examples of the invention.

Fig. 19 is a schematic diagram illustrating a light emitting device according to some examples of the invention.

Fig. 20 is a schematic diagram illustrating a light emitting device according to some examples of the invention.

Fig. 21 is a schematic diagram illustrating a light emitting device according to some examples of the invention.

Fig. 22 is a schematic diagram illustrating a light emitting device according to some examples of the invention.

Fig. 23 is a schematic diagram illustrating a light emitting device according to some examples of the invention.

Fig. 24 and 25 are a schematic plan view and a partial side sectional view, respectively, illustrating a light-emitting device according to some examples of the invention.

Fig. 26 is a schematic diagram illustrating a light emitting device according to some examples of the invention.

Detailed Description

The following is a detailed description of the led chip and the method for making the same according to the present invention, and before further describing the present invention, it should be understood that the present invention is not limited to the specific embodiments described below, since modifications can be made to the specific embodiments. It is also to be understood that the embodiments are presented by way of illustration, not limitation, since the scope of the invention is defined by the appended claims. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.

In the following description, similar or identical components will be denoted by the same reference numerals.

Fig. 1 shows a conventional LED lighting device, which includes a package support 110, an LED chip 120 and a packaging material layer 130, wherein the support 110 includes a bottom 111 and a sidewall 112, wherein a chip mounting area 1101, a first wire bonding area 1102 and a second wire bonding area 1103 are disposed on an upper surface of the bottom, wherein the first wire bonding area 1102 and the second wire bonding area 1103 are electrically isolated from each other, the LED chip 120 is mounted on the chip mounting area 1101 in a horizontal structure, p and n electrodes are located on a light emitting surface and are connected to the first wire bonding area 1102 and the second wire bonding area 1103 of the support 110 through

leads

141 and 142, respectively, and the packaging material layer 130 seals the chip 120 on the support 110. Further, the package support 110 may include a bottom 111 and a sidewall 112, which form a space for accommodating the LED chip 120. In the light emitting device, the electrodes of the LED chip 120 are located on the light emitting surface, and have a light shielding and/or light absorbing effect. On the other hand, the electrodes are located on the epitaxial stack, and the wire bonding process may damage the epitaxial stack.

Fig. 2 shows another conventional LED lighting device. The LED chip 120 used in the light emitting device is an inverted structure, and its electrode faces the bottom surface 111 of the support. The light emitting device can solve the problems of light shading and light absorption of the electrode on the light emitting surface in the light emitting device shown in fig. 1. However, flip chip mounting requires special equipment and alignment.

Fig. 3 shows a light-emitting device implemented in accordance with the present invention. The light emitting device includes: support 210, LED chip 220, packaging material layer 230. Specifically, the bracket 210 comprises a bottom 211 and a wall 212 forming a cup structure, wherein the top surface of the bottom 211 is provided with a chip mounting area 2101, a first wire bonding area 2102 and a second wire bonding area 2103, wherein the first wire bonding area 2102 and the second wire bonding area 2103 are electrically isolated from each other. The LED chip 220 is mounted on the mounting area 2101 of the bracket with the light-emitting surface facing upward, and its p and n electrodes are connected to the first bonding area 2102 and the second bonding area 2103 of the bracket 210 by

leads

241 and 242, respectively. The packaging material layer packages the LED chip on the support.

Fig. 4 shows a structure of an LED chip 220 for the light emitting device shown in fig. 3, which comprises, in order from top to bottom: an epitaxial stack 2210, a first electrode 2221, a second electrode 2222, an electrical connection layer 2240, and a substrate 2230. The epitaxial stack of LED chips is supported by a base 2230, the upper surface S11 of the epitaxial stack 2210 acting as a light exit surface, without a growth substrate. Here, "no growth substrate" means that the growth substrate used for growth is removed from the epitaxial stack or at least substantially thinned, if necessary.

Specifically, the epitaxial stack 2210 has an upper surface S11 and a lower surface S12 opposite to each other, wherein the upper surface S11 is used as a light emitting surface, and comprises a first semiconductor layer 2211, an active layer 2212 and a second semiconductor layer 2212, wherein the first semiconductor layer 2211 and the second semiconductor layer 2213 can be a p-type semiconductor layer and a second semiconductor layer 2213 respectivelyAn n-type semiconductor layer. For example, the first semiconductor layer and the second semiconductor layer may be formed of Al by the chemical formula_xIn_yGa_(1-x-y)N (where 0. ltoreq. x.ltoreq.1, 0. ltoreq. y.ltoreq.1, 0. ltoreq. x + y. ltoreq.1), but not limited thereto, a GaAs-based semiconductor or a GaP-based AlGaInP semiconductor material may also be used. The active layer 2212 may have a nitride-based multi-quantum well structure (MQW) such as InGaN/GaN, GaN/AlGaN, etc., but is not limited thereto, and other semiconductors such as Galas/AlGaAs, InGaP/GaP, GaP/AlGaP, etc. may also be used.

The electrical connection layer 2240 is formed on the lower surface S12 of the epitaxial stack and includes a first electrical connection layer 2241 and a second electrical connection layer 2242, both ends of the first electrical connection layer 2241 are connected to the first semiconductor layer 2211 and the first electrode 2221, respectively, and both ends of the second electrical connection layer 2241 are connected to the second semiconductor layer 2213 and the second electrode 2222, respectively. The materials of the first and second

electrical connection layers

2241 and 2242 may be the same or different. The material of the first electrical connection layer 2241 may be Ag, Au, Ti, Al, Cr, Pt, TiW, Ni or any combination thereof, where Ag and Al are suitable as metal reflective material, TiW is suitable as metal cladding material to prevent metal diffusion, and Cr, Ni, and Au are suitable as ohmic contact material. In order to reduce the resistance between the first electrical connection layer 2241 and the first semiconductor layer 2211, a transparent current spreading layer is also added between the first electrical connection layer 2241 and the first semiconductor layer 2211. The second electrical connection layer includes an ohmic contact layer having good electrical connection properties with the second semiconductor layer 2213, such as Cr, Ni, Au, Al, or the like. The material of the second electrical connection layer can be Ag, Au, Ti, Al, Cr, Pt, TiW, Ni or any combination of the above, wherein Ag and Al are suitable to be used as a metal reflection material, TiW is suitable to be used as a metal coating material to prevent metal diffusion, and Cr, Ni and Au are suitable to be used as ohmic contact materials.

The first electrode 2221 and the second electrode 2222 are located outside the epitaxial stack 2210, i.e., the projections of the first electrode 2221 and the second electrode 2222 on the surface of the substrate 2230 are located outside the region of the epitaxial stack 2210. The first and second electrodes are led out from the lower surface S12 of the epitaxial stack 2210 through the electrical connection layer 2240 toward the upper surface S11 of the epitaxial stack, thereby being adapted to electrically contact the body of the light emitting diode chip from the front side. Preferably, the upper surfaces of the first electrode and the second electrode are located at the same height.

The substrate 2230 is for supporting the epitaxial stack 2210, and preferably has a thickness of 50 μ 0 to 200 μm. In some embodiments, the thickness of the substrate 2230 can be 50 to 100 μm, such as 90 μm; in some embodiments, the thickness of the substrate 2230 can also be 100 to 150 μm, such as 120 μm or 130 μm; in some embodiments, the thickness of the substrate 2230 can also be 150 to 200 μm, such as 180 μm. The substrate 2230 is preferably made of an insulating material, and may be made of a transparent material, such as a sapphire substrate, a ceramic substrate, or a highly reflective material.

In the light-emitting device, the first electrode and the second electrode are positioned on the side part of the epitaxial lamination, so that the shielding of radiation caused by the arrangement of the first electrode and/or the second electrode above the epitaxial lamination is avoided, the radiation efficiency is reduced, and the wire bonding is conveniently manufactured.

In some embodiments, the substrate 2230 may be made of a material with good heat dissipation property, such as Si substrate, Cu substrate or ceramic substrate, and the electrical connection layer 2240 is connected to the heat dissipation substrate 2230 and the second semiconductor layer 2213 to form a good heat conduction channel for guiding heat from the second type semiconductor layer to the heat dissipation substrate. Since excitation radiation of the multiple quantum wells is emitted through the second semiconductor layer, heat is easily accumulated in the second semiconductor layer 2213, and the electric connection layer 2242 favorably extracts heat from the second semiconductor layer to the heat dissipation substrate.

Fig. 5 shows a structure of an LED chip 220 used in the light emitting device shown in fig. 3. In the LED chip, the electrical connection layers 2240 are arranged in multiple layers in the vertical direction, and are electrically isolated by the insulating layer 2260. Specifically, a third electrical connection layer 2244, an insulating layer 2260, a first conductive guide 2241 and a second electrical connection layer 2242 are sequentially disposed between the substrate 2230 and the epitaxial stack 2210 from bottom to top, the third electrical connection layer 2244 has a first extension part 2243 and a second extension part 2245 facing the epitaxial stack, the first extension part 2243 penetrates through the first semiconductor layer 2221 and the active layer 2222, and is electrically connected to the second semiconductor layer 2213 through the opening 2271, and the second extension part 2245 is electrically connected to the second electrical connection layer 2242 through the opening 2272. Preferably, the first electrical connection layer 2241 and the second electrical connection layer 2242 have the same thickness and material, and are formed in the same step by patterning, so that the first and second electrical connection layers may have the same height, thereby facilitating the subsequent fabrication of the first and second electrodes having the same height.

In a specific embodiment, a portion of the first electrical connection layer 2241 contacting the first electrode 2221 and a portion of the second electrical connection layer 2242 contacting the second electrode 2222 are made of a material with relatively stable performance, such as Ti, Pt, Au, Cr, TiW alloy, etc., and the first electrical connection layer 2241 located under the light-emitting region includes a highly reflective metal material (e.g., Ag, Al, etc.) sequentially reflecting light emitted from the light-emitting region and a stable metal material (e.g., Ti, Pt, Au, Cr, TiW, etc.) for preventing diffusion of the above materials. The third electrical connection layer 2244 includes an extension 2243 extending toward the light emitting surface and connected to the second semiconductor layer 2213, and the material thereof preferably includes a reflective material such as Al, Cr, or Ag. Further, a side of the third electrical connection layer 2244 in contact with the substrate 2230 may include a bonding layer for bonding the substrate. More preferably, the bonding layer is a metal material and can also serve as a heat sink layer, thereby rapidly extracting heat accumulated in the second semiconductor layer to the substrate 2230. Substrate 2230, on the other hand, is in contact with the entire face of the epitaxial stack, ensuring physical structural integrity.

In some embodiments, the epitaxial stack 2210 of the LED chip 220 is removed from the growth substrate and has a thin film structure, and the first electrical connection layer 2241 may include the reflective layer M1, so that the distance D1 from the reflective layer M1 to the light emitting surface S11 of the LED chip is within 10 μ M, for example, 4 to 8 μ M, and the distance D3 to the light emitting layer is less than 1 μ M, thereby shortening the path of light inside the LED chip and increasing the ratio of light emitted from the light emitting surface S11 by the active layer 2212, wherein the light emitting angle is preferably less than 150 °, and more preferably less than or equal to 120 °, for example, 120 to 110 °, and in a specific embodiment, the light emitting angle of the LED chip may be 113 °, or 115 °, or 118 °.

Further, the third electrical connection layer 2244 may include a reflective layer M2, the reflective layer M2 is located on the substrate 2230, and a distance from the light-emitting surface S11 is preferably less than 20 μ M, and is much less than half of the thickness T of the LED chip, and more preferably, is 7 to 12 μ M, for example, 8 μ M, or 9 μ M, or μ M.

Fig. 6 shows a structure of an LED chip 220 used in the light emitting device shown in fig. 3. Unlike the LED chip shown in fig. 5, the third electrical connection layer 2244 includes a plurality of extension portions 2243 extending toward the light emitting surface, and the plurality of extension portions 2243 penetrates the first semiconductor layer 2211 and the active layer 2212 and is connected to the second semiconductor layer 2213. The plurality of extension portions 2243 are preferably uniformly distributed, thus having better current spreading and heat dissipation characteristics, and being suitable for applications under high current density.

Preferably, the total contact area of the third electrical connection layer 2244 and the second semiconductor layer 2213 is more than 1.5% of the area of the second semiconductor layer 2213. The contact area between the third electrical connection layer 2243 and the second semiconductor layer 2213 can be designed according to requirements, for example, 2.3% -2.8%, 2.8% -4%, or 4% -6% can be selected. In some embodiments, increasing the direct contact area of the third electrical connection layer 2244 and the second semiconductor layer 2213 may solve the heat dissipation problem of high power products, such as large-sized chips or high-voltage chips.

In some embodiments, the diameter of the extension 2243 is 15 μm or more. Although the heat dissipation characteristic can be improved by securing the total contact area of the third electrical connection layer 2244 and the second semiconductor layer 2213, if the diameter of the extension part 2243 is small, the thin extension part 2243 has thermal resistance exceeding the linear proportion, and thus in some embodiments, the diameter of the extension part 2243 is designed to be 32 μm to 40 μm, which is more excellent in the heat dissipation effect. In a preferred embodiment, when the diameter of the extension portions 2243 is 34 μm to 36 μm, the number of the extension portions 2243 is set to 20 to 25.

In some embodiments, the first electrical connection layer 2241 and the second electrical connection layer 2242 have the same structure layer, and include a metal reflective layer M1, the side of the third electrical connection layer 2244 close to the epitaxial stack may include a metal reflective layer M2, the lower surface S12 of the epitaxial stack 2210 is substantially covered by the metal reflective layers M1 and M2, and the downward light emitted from the active layer 2212 is directly reflected without passing through the substrate, which causes part of the light to be absorbed. For example, the first and second

electrical connection layers

2241 and 2242 may include an Ag metal layer as the first reflective layer M1, and the third electrical connection layer 2244 includes an Al metal layer, which may form an ohmic contact with the second semiconductor layer 2213 on the one hand, and as the second reflective layer M2 on the other hand, as much as possible to cover the region of the lower surface S12 of the epitaxial stack not covered by the first and second

electrical connection layers

2241 and 2242.

Preferably, the LED chip 220 has the growth substrate removed, and a rough surface 2210a may be disposed on the light emitting surface S11.

Figure 7 schematically illustrates a light-emitting device in accordance with embodiments of the present invention. The light-emitting device is provided with at least two reflecting layers: m2 and M3, comprising: support 210, LED chip 220, packaging material layer 230. Wherein the support 210 comprises a bottom portion 211 and a wall portion 212, which form a bowl structure, the surface of the chip mounting region 2101 of which can be plated with a reflective layer M3, the LED chip 220 is mounted in the bowl by a bonding layer 250, and an encapsulation material layer 230 filling the bowl to encapsulate the LED chip 220.

Specifically, the reflective layer M3 on the surface of the mount 210 may be a metal reflective layer (e.g., a high-reflectivity material such as Ag or Al), an insulating reflective layer (e.g., DBR), or a reflective adhesive (e.g., white adhesive), and preferably has a thickness of 5 μ M or less. The bonding layer 250 is a transparent material, and preferably has a light transmittance of 70% or more, more preferably 80% or more. The LED chip 220 has a transparent substrate 2230, and a reflective layer M2 is provided on the upper surface side of the substrate 2230. The transparent substrate 2230 has a visible light transmittance of 80% or more, preferably 90% or more, and may be made of sapphire, transparent ceramic, glass, or the like.

In some embodiments, the LED chip may refer to the structure shown in fig. 4, in which case the substrate of the LED chip is a transparent substrate, and the first electrical connection layer 2241 may serve as the reflective layer M2. The first electrical connection layer 2241 may be formed by stacking a plurality of layers, and includes a highly reflective material layer, for example, a highly reflective metal material such as aluminum, and the thickness of the highly reflective material layer is preferably 50 nm or less.

The LED chip 220 also adopts the structure shown in fig. 5 or fig. 6, wherein the substrate 2230 is made of a transparent material, and the third electrical connection layer 2243 on the upper surface thereof can be used as the light reflecting layer M2. In some embodiments, the third electrical connection layer 2243 is made of a metal material, and has a reflectivity of 70% or more, and can directly serve as a reflective layer. In some embodiments, the third electrical connection layer 2243 is formed by stacking a plurality of layers, wherein a side contacting the substrate 2230 includes a highly reflective material layer, such as a highly reflective metal material, e.g., aluminum, and the thickness of the highly reflective material layer is preferably 50 nm or less.

The substrate size of the LED chip 220 shown in fig. 4 to 6 is generally larger than the size of the epitaxial stack 2210 (the cross-sectional area of which is larger than that of the epitaxial stack 2210), and the thickness is much larger than that of other structural layers, taking a GaN-based LED chip as an example, the thickness of the epitaxial stack 2210 is generally not more than 10 μm, for example, 4 to 8 μm, the total thickness of the electrical connection layer, the insulating layer, the bonding layer, and the like between the epitaxial stack 2210 and the substrate 2230 is generally not more than 5 μm, for example, it may be 3 to 5 μm, and the thickness of the substrate 2230 is usually 50 μm or more, for example, 50 μm, or 100 μm, or 120 μm, or 150 μm, or 180 μm, therefore, light emitted from the active layer is easily incident to the inside of the substrate 2230 through reflection of the sidewalls of the support or scattering and reflection of the encapsulating material layer, and may be absorbed by the metal above the substrate 2230 or the metal on the support. In the light emitting device shown in fig. 7, part of light emitted from the LED chip 220 due to reflection from the bowl is incident into the transparent substrate 2230, and the reflective layers are disposed above and below the transparent substrate 210, so that light is emitted from the other end and is less absorbed by the bonding layer metal or the metal of the support 210, as shown in fig. 8.

In some embodiments, the encapsulating material layer 230 encapsulating the LED chip 220 contains particles 231, and a portion of light emitted from the LED chip 220 is reflected or scattered to the side of the transparent substrate, and since the transparent substrate 210 has a reflective layer on both the top and bottom, the light can exit from the other end and is not absorbed by the bonding layer metal or the metal of the support.

In some embodiments, the LED chip is covered with phosphor powder around and above, part of the light emitted from the LED chip 220 will be reflected or scattered to the side of the transparent substrate, and since the transparent substrate 210 has reflective layers above and below, the light will be emitted from the other end and will not be absorbed by the bonding layer metal or the metal of the support. Preferably, for the uniformity of the light color of the light emitting device, the phosphor is covered below the plane where the reflective layer M2 is located, and at this time, the transparent substrate 2230 is combined with the upper and lower reflective layers, which can significantly reduce the absorption of the light emitted from the LED chip 220 entering the substrate through reflection or scattering.

Figure 9 schematically illustrates a light-emitting device in accordance with embodiments of the present invention. The light-emitting device likewise has at least two reflective layers M2 and M3, and the LED chip 220 used has a transparent substrate 2230. Unlike the light emitting device shown in fig. 7, the reflective layer M3 under the transparent substrate 2230 is formed directly on the back surface of the substrate 2230, and may be a metal reflective layer (e.g., a material having high reflectivity such as Ag or Al) or an insulating reflective layer (e.g., DBR).

Fig. 10 shows a structure of an LED chip 220 used in the light emitting device shown in fig. 9, which is substantially the same as the LED chip shown in fig. 5 except that: a transparent substrate 2230 is selected, and a reflective layer M3 is provided on the back surface of the transparent substrate 2230. In some embodiments, the structure shown in fig. 4 or fig. 6 may also be adopted, and the reflective layer M3 is also disposed on the back surface of the substrate 2230 of the LED chip 220 shown in fig. 4 or fig. 6.

Figure 11 schematically illustrates a light-emitting device in accordance with embodiments of the present invention. The light emitting device includes: the support 210 and the LED chip 220 are mounted on the support 210 by a bonding layer 250, and the LED chip 220 is covered by an encapsulating material layer 230 so that the LED chip 220 is sealed on the support. The LED chip includes an epitaxial stack 2210, a substrate 2230, and a bonding layer 2280 connecting the two, wherein a first reflective layer M21 (or M1) and a second reflective layer M22 are disposed on and under the bonding layer 2280.

Fig. 12 shows a structure of an LED chip 220 used for the light emitting device shown in fig. 9. The LED chip comprises the following components in sequence from top to bottom: the epitaxial stack 2210, the first electrode 2221/the second electrode 2222, the first electrical connection layer 2241/the second electrical connection layer, the insulating layer 2260, the third electrical connection layer 2244, the bonding layer 2280, the reflective layer 2290, and the substrate 2230. Wherein the first reflective layer may be the first electrical connection layer 2241 and/or the third electrical connection layer 2244. Preferably, the third electrical connection layer 2244 electrically connects the second semiconductor layer 2213 and the first electrical connection layer 2242, and includes a reflective material such as Al, Cr, or Ag as the first reflective layer M21. The bonding layer 2280 is used to bond the epitaxial stack 2210 and the substrate 2230, and the material thereof may be selected from a metal material or a non-metal material as needed.

In some embodiments, the light emitting device is used at high current densities (e.g., current densities ≧ 1A/mm)²May be 2A/mm²Or 3A/mm²) The bonding layer 2280 is preferably made of a metal bonding material, and in this case, the reflective layer 2290 is also preferably made of a highly reflective metal material (e.g., aluminum, silver, etc.), so that a heat dissipation channel can be formed to facilitate the heat accumulated in the second semiconductor layer 2213 to be conducted to the support 210 through the third conductive layer 2244, the bonding layer 2280, the reflective layer 2290, and the substrate 2230 and be conducted out of the support 210. In some embodiments, the bonding layer 2280 of the light emitting device may also be an insulating layer, and in this case, the reflective layer 2290 may be a metal reflective layer or an insulating reflective layer.

Fig. 13 shows a structure of an LED chip 220 used for the light emitting device shown in fig. 9. Unlike the structure of the LED chip shown in fig. 12, the side wall 2281 of the bonding layer 2280 is coated with a reflective layer. In the light emitting device with the LED chip 220 mounted thereon, light emitted from the LED chip 220 is reflected by the sidewall of the support 210 or reflected and/or scattered by the encapsulating material layer 230 to the bonding layer 2280, and is directly reflected by the reflective layer coated on the sidewall 2281 of the bonding layer, thereby preventing the light from entering into the interior 2280 of the bonding layer.

Figure 14 schematically illustrates a light-emitting device in accordance with an embodiment of the present invention. Unlike the light emitting device shown in fig. 11, a reflective layer 260 is provided on a surface of the chip mounting region 2101 of the support 210, and the LED chip 220 is mounted on the reflective layer 260 by a bonding layer 250, wherein the substrate 2230 is a transparent material, wherein the light transmittance of the substrate is preferably 70% or more. The LED chip structure can refer to the structure shown in fig. 12 and 13.

In the light emitting device, at least three reflective layers are included: a first reflective layer M22 and a third reflective layer M3, wherein the first reflective layer is disposed above the bonding layer 2280, which may be M1 or M21, and is mainly used for directly reflecting the light emitted from the active layer of the LED chip downwards, and has a distance of 10 μ M or less, such as 4 to 8 μ M, from the light emitting surface S11 of the LED chip, the second reflective layer M22 is disposed between the bonding layer 2280 and the transparent substrate 2230, and has a distance of 20 μ M or less, such as 7 to 10 μ M or 10 to 15 μ M from the light emitting surface S11 of the LED chip, the third reflective layer M3 is disposed between the transparent substrate 2230 and the support 210, and has a distance of 50 μ M or more from the light emitting surface S11 of the LED chip, the second reflective layer M22, the third reflective layer M3 and the transparent substrate 2230 form a light transmission channel, and a part of the light emitted from the LED chip 220 due to the reflection from the side wall 210 of the support is incident into the transparent substrate 2230, light may be emitted from the other end of the transparent substrate 2230 and be less absorbed by the bonding layer 2280 or the scaffold 210.

Figure 15 schematically illustrates a light-emitting device in accordance with embodiments of the present invention. The light emitting device also includes at least three reflective layers a first reflective layer, a second reflective layer M22, and a third reflective layer M3, unlike the light emitting device shown in fig. 14, the third reflective layer M3 is positioned between the bonding layer 250 and the transparent substrate 2230. Fig. 16 shows a structure of an LED chip 220 used in the light emitting device shown in fig. 15, and the third reflective layer M3 is formed on the back surface of the transparent substrate 2230.

Figure 17 schematically illustrates a light-emitting device in accordance with embodiments of the present invention. Unlike the light emitting device shown in fig. 11, the LED chip 220 of the light emitting device has a reflective substrate 2230, preferably having a reflectance of 90% or more, which may be white ceramic, and the bonding layer 250 for fixing the LED chip 220 is preferably a reflective material having a reflectance of 80% or more, which may be white die attach adhesive. As for the specific structure of the LED chip 220, referring to the structure shown in fig. 5 or 6, the substrate 2230 is a reflective substrate, and one side of the third electrical connection layer 2244 adjacent to the substrate includes a bonding layer 2280. The reflective layer M1 and/or M21 is disposed above the bonding layer 2280, so that downward light emitted from the active layer is directly reflected without passing through the bonding layer to cause a part of the light to be absorbed. Meanwhile, part of light emitted from the LED chip 220 of the light emitting device is irradiated onto the surface of the reflective substrate 2230 due to reflection from the side wall of the support, and can be directly reflected, thereby reducing absorption of the substrate 2230 or the support 210.

In some embodiments, the encapsulating material layer 230 encapsulating the LED chip 220 contains particles 231, and a portion of light emitted from the LED chip 220 is reflected or scattered to the side of the reflective substrate 2230 and directly reflected.

In some embodiments, the LED chip is covered with phosphor powder around and above, and a part of the light emitted from the LED chip 220 will be reflected or scattered to irradiate the side of the reflective substrate, and be reflected directly.

Fig. 18 is a simplified schematic diagram of a variation of the light emitting device of fig. 17. The substrate of the LED chip 220 of the light emitting device is not limited to a reflective substrate, and may be a transparent substrate (e.g., sapphire substrate, glass substrate, etc.) or a light-absorbing substrate (e.g., silicon substrate, etc.), and the reflective layer 2231 is formed on the sidewall of the substrate.

Figure 19 schematically illustrates a light-emitting device in accordance with embodiments of the present invention. The same parts as those of the light-emitting device shown in fig. 3 are not described again, except that: a reflective material layer 231 is disposed below the packaging material layer 230, and surrounds the outer side surface S13 of the LED chip 220, but does not cover the light emitting surface S11 of the LED chip. The reflective material may be silicone, epoxy, or a silicone-epoxy hybrid material, such as white glue. Preferably, the upper surface S21 of the light reflecting material layer 231 is not lower than the upper surface S14 of the substrate 2230 of the LED chip.

In the light emitting device shown in fig. 3, the thickness of the LED chip 220 is mainly determined by the thickness of the substrate 2230, which is generally greater than 50 μ 0, for example, 100 μm, so that when the light emitting device is operated such that the light emitted from the LED chip 220 enters the encapsulating material layer 230, a portion of the light is reflected or scattered and easily enters the substrate from the side surface of the substrate 2230, and is absorbed by the substrate, the support, or the LED chip. The light emitting device shown in fig. 19 fills the reflective material layer 231 around the LED chip between the encapsulating material layer and the support, and the reflective material layer 231 is not lower than the upper surface S14 of the substrate 2230, so that the light emitted by the LED chip can be effectively prevented from being reflected or scattered and then entering the substrate 2230 after entering the encapsulating material layer 230.

In some embodiments, the distance H1 between the upper surface S21 of the reflective material layer and the light emitting surface S11 of the LED chip is preferably within 20 μm, and more preferably within 10 μm. In one particular embodiment, the layer of light reflecting material 231 surrounds the LED core 220 up to the upper surface S14 of the substrate 2230. In some embodiments, the layer 231 of light reflecting material surrounds the LED chip 220 up to cover the electrodes of the LED chip, as shown in fig. 20. In some embodiments, the layer of light reflecting material 231 surrounds the LED chip 220 up to flush with the upper surface of the LED chip, as shown in fig. 21.

Figure 22 schematically illustrates a light-emitting device in accordance with embodiments of the present invention. Unlike the light emitting device shown in fig. 3, the support 210 of the light emitting device does not have a cup structure, such as a flat plate structure, and the encapsulating material layer 230 covers the LED chip and the leads. In some preferred embodiments, the encapsulating material layer 230 forms a lens structure 232 corresponding to the LED chip 220, and the lens structure 232 may be made of the same material as the encapsulating material layer 230 or different material.

FIG. 23 schematically illustrates a light-emitting device in accordance with embodiments of the present invention. Unlike the light emitting device shown in fig. 22, a reflective material 231 surrounding the LED chip 220 is disposed between the support 210 and the packaging material layer 230, and the reflective material 231 may be flush with the light emitting surface S11 of the LED chip or lower than the light emitting surface S11.

Fig. 24 and 25 are simplified illustrations of a light emitting device implemented in accordance with the present invention. The light emitting device includes a support 210, and at least two LED chips 220 and a packaging material layer (not shown) mounted on the support.

In the light emitting device, the plurality of LED chips 220 are mounted in the same support 210, and adjacent LED chips 220 block light mutually. Defining OL as the overlapping length of two adjacent LED chips 220, L as the length of the LED chips, W as the width of the LED chips, P as the perimeter of the LED chips 220, i.e. 2 × (L + W), T as the thickness of the LED chips 220, G as the distance between the adjacent LED chips 220, the light blocking between the LED chips is mainly related to the thickness T of the chips, the gap G between the chips, and the overlapping length of the adjacent LED chips, specifically: proportional to the thickness T of the LED chips, inversely proportional to the gap G between the LED chips, proportional to the proportion (OL/P) of the total area of the side surfaces of the chips in the region where the adjacent LED chips overlap, thus defining light blocking factors F1 and F2, where F1 ∞ T/G, F2 ℃ OL/P, defining a light blocking coefficient R = F1 × F2, the greater the R, the greater the side light blocking influence between the LED chips. In this embodiment, the light emitting device employs the LED chip shown in fig. 5 or 6, and a reflective layer M1 or M21 is disposed between the epitaxial stack 2210 and the substrate 2230, where a distance D1 from the reflective layer to the light emitting surface S11 of the LED chip may be less than 10 μ M, and a distance D2 from the active layer may be less than 5 μ M, so that the light emitting angle of the LED chip is smaller, preferably equal to or less than 120 °, for example, 110 to 120 °, and the light emitted from the active layer 2212 is mainly emitted from the light emitting surface S11, so that the side light blocking effect between the LED chips is smaller, the distance G between adjacent chips may be 150 μ M, preferably 50 to 120 μ M, and the light blocking effect and the package size can be considered, and correspondingly, the light blocking coefficient R preferably takes a value of 0.2 or more, so that the space can be more fully utilized, and at the same time, the package size is reduced or the area of the chip is increased under the same package size, thereby improving the light efficiency. Preferably, the light blocking coefficient R is preferably 0.2-2.

In one embodiment, the dimensions of the LED chips are as follows: length L is 1000 μm, width W is 500 μm, height T is 150 μm, overlap length OL between adjacent LED chips is 500 μm, pitch G is 100 μm, then R = 0.25. In another embodiment, the LED chips are unchanged in size, the overlap length OL between adjacent LED chips is 1000 μm, the pitch G is 100 μm, and then R = 0.5. In another embodiment, the LED chips are unchanged in size, overlap length OL is 1000 μm, and pitch G is 50 μm, then R = 1.

In some embodiments, a wavelength conversion layer may be provided as desired, and the wavelength conversion layer may be doped with phosphor directly in the encapsulating material layer or may be a wavelength conversion sheet. Preferably, the wavelength conversion layer is formed above the plane of the upper surface of the LED chip, and preferably, the wavelength conversion layer is provided only on the light emitting surface of the LED chip.

Fig. 26 is a simplified diagram showing a light-emitting device, which is different from the light-emitting device shown in fig. 24 in that the light-emitting device includes a support and at least three LED chips disposed on the support, the LED chips emit different spectra, such as red, blue and green light, respectively, and the support can be a flat plate structure or a bowl-cup structure. Any one of the LED chips shown in fig. 4 to 6 can be used as the LED chip.

In some embodiments, the light emitting device is required to be at 4A/mm²Even 5A/mm²For example, in this case, the LED chip shown in fig. 6 is preferably used. Specifically, the substrate 2230 is preferably an insulating substrate with good heat dissipation, such as a ceramic substrate, which can realize a thermoelectric separation structure, provide a good foundation for high current density driving, and rapidly introduce and guide heat generated by the epitaxial stack to the support; further, the light emitting angle of the LED chip is smaller than or equal to 120 degrees, for example, 120-110 degrees, and under the condition that the light efficiency is not changed, the packaging size can be effectively reduced, or the area of the chip is increased under the same packaging size. In one embodiment, the light emitting device is applied to stage lamps, and comprises A, B, C, D four LED chips respectively emitting white light, red light, blue light and green light. The light emitting surface of the white light LED chip is coated with fluorescent powder for emitting white light. The distance between every two LED chips is 50-150 micrometers.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements should also be considered as the protection scope of the present invention.

Claims

1. A light emitting device comprising:

a support having a mounting surface for mounting an LED chip;

more than two LED chips mounted on the mounting surface of the bracket;

the packaging material layer covers the surface of the LED chip and seals the LED chip on the support;

the method is characterized in that: the light-emitting angle of the LED chip is less than or equal to 120 degrees, the upper surface of the LED chip is a light-emitting surface, the LED chip comprises a substrate, an epitaxial lamination layer, a first electrode, a second electrode and a reflecting layer, the first electrode and the second electrode are respectively LED out from the lower surface of the epitaxial lamination layer through a conducting layer and face the upper surface of the epitaxial lamination layer, and the distance between the reflecting layer and the light-emitting surface is less than 10 microns.

2. The lighting device of claim 1, wherein: defining OL to be the overlapping length of two adjacent LED chips, P to be the perimeter of the LED chips, T to be the thickness of the chips, G to be the space between the adjacent LED chips, and R to be the light blocking coefficient, then R = (OL/P) × (T/G) ≧ 0.2.

3. The lighting device according to claim 2, wherein: the light blocking coefficient R is 0.2-2.

4. The lighting device of claim 1, wherein: the distance between the reflecting layer and the light-emitting surface is 4-8 mu m.

5. The lighting device of claim 1, wherein: the first and second electrodes are located outside the epitaxial stack.

6. The light-emitting device according to claim 1 or 5, wherein: the support is provided with a first welding line area and a second welding line area, the first welding line area and the second welding line area are electrically isolated from each other, and the first electrode and the second electrode are respectively connected to the first welding line area and the second welding line area of the support through leads.

7. The lighting device according to claim 6, wherein: the epitaxial lamination removes the growth substrate, the upper surface of the growth substrate is a light-emitting surface, and the growth substrate sequentially comprises a first semiconductor layer, an active layer and a second semiconductor layer from bottom to top.

8. The lighting device according to claim 6, wherein: the LED chip further comprises a first electric connection layer and a second electric connection layer, wherein the first electric connection layer is electrically connected with the first semiconductor layer and the first electrode, and the second electric connection layer is electrically connected with the second semiconductor layer and the second electrode.

9. The lighting device of claim 8, wherein: the third electric connection layer is positioned below the first and second electric connection layers and is provided with at least one first extension part and one second extension part, wherein the first extension part penetrates through the first semiconductor layer and the active layer and is in contact with the second semiconductor layer, and the second extension part is in contact with the second electric connection layer.

10. The lighting device of claim 9, wherein: the third electrical connection layer comprises a second reflective layer and a bonding layer.

11. The lighting device of claim 9, wherein: the third electric connection layer and the substrate form a heat dissipation channel, and when the light-emitting device works, heat accumulated in the second semiconductor layer is led to the support and is led out.

12. The lighting device of claim 1, wherein: the distance between the LED chips is less than or equal to 150 μm.

13. The lighting device of claim 12, wherein: the distance between the LED chips is 50-120 mu m.

14. The lighting device of claim 1, wherein: the upper surface of the LED chip is a light-emitting surface and comprises an epitaxial lamination layer, a first reflecting layer, a second reflecting layer and a substrate from top to bottom.

15. The lighting device of claim 14, wherein: the epitaxial stack comprises a first semiconductor layer, an active layer and a second semiconductor layer, and the distance between the reflecting layer and the active layer is less than 1 μm.

16. The lighting device of claim 14, wherein: and a third reflection is also formed between the substrate and the bracket.

17. The lighting device of claim 16, wherein: the distance between the second reflecting layer and the light emergent surface is less than 20 μm.

18. The lighting device of claim 14, wherein: the substrate is transparent to light emitted by the epitaxial stack.

19. The lighting device of claim 14, wherein: the substrate is a high-reflection substrate, and the reflectivity of the substrate is more than 90%.

20. The lighting device of claim 1, wherein: the LED chip also comprises a light conversion layer which is positioned on the plane where the light-emitting surface of the LED chip is positioned.

21. The lighting device of claim 1, wherein: at least three LED chips are included, each LED chip emitting in a different spectrum.

22. The lighting device of claim 1, wherein: the LED light source comprises four LED chips, wherein a light emitting surface of one LED chip is coated with a fluorescent layer.