TWI628808B - Light-emitting device - Google Patents

Abstract

A light-emitting element comprising a transparent substrate; a light-emitting layer; a reflective structure, wherein the transparent substrate is located between the light-emitting layer and the reflective structure; and a cavity between the transparent substrate and the reflective structure; The transparent substrate has a recess facing the reflective structure to form at least a portion of the cavity.

Description

Light-emitting element

The present invention relates to a light-emitting element, and more particularly to a light-emitting element capable of improving light extraction efficiency.

A light-emitting diode (LED) is a solid-state semiconductor device, and the LED generally includes a p-type semiconductor layer, an n-type semiconductor layer, and an active layer between the p-type semiconductor layer and the n-type semiconductor layer. . The light-emitting diode system injects holes and electrons into the active layer through the p-type semiconductor layer and the n-type semiconductor layer to radiate and illuminate, thereby converting electrical energy into light energy.

A light emitting device comprising: a transparent substrate; a light emitting laminate; a reflective structure, wherein the transparent substrate is located between the light emitting laminate and the reflective structure; and a cavity between the transparent substrate and the reflective structure Wherein the transparent substrate has a recess facing the reflective structure to form at least a portion of the cavity.

1‧‧‧ Ontology

11‧‧‧Lighting laminate

111‧‧‧First type semiconductor layer

112‧‧‧Second type semiconductor layer

113‧‧‧Active layer

12‧‧‧Transparent substrate

121‧‧‧ upper surface

122‧‧‧ lower surface

123‧‧‧ recess

12E‧‧‧ Periphery

13‧‧‧buffer layer

14‧‧‧First electrode

15‧‧‧second electrode

16‧‧‧ conductive path

17‧‧‧Insulation coating

2‧‧‧Reflective structure

21‧‧‧Reflective laminate

211‧‧‧First reflective layer

212‧‧‧second reflective layer

22‧‧‧Metal reflector

23‧‧‧Connection layer

24‧‧‧ recess

2a‧‧‧ surface

2E‧‧‧ Periphery

3‧‧‧ Cavity

4‧‧‧ Carrier

41‧‧‧ top surface

42‧‧‧ bottom

43‧‧‧First Guide

44‧‧‧Second Guide

5‧‧‧ bonding layer

5'‧‧‧ joint layer

R‧‧‧ recessed area

E1‧‧‧First connector

E2‧‧‧Second connector

T‧‧‧ thickness

R1‧‧‧ roughened surface

P‧‧‧ protective layer

M‧‧ ‧ baffle

M1‧‧‧ first board

M2‧‧‧ second board

O1‧‧‧ first opening

O2‧‧‧ second opening

Fig. 1 is a cross-sectional view showing a light-emitting element of a first embodiment of the present invention.

Fig. 2A is a graph showing the relationship between the reflectance and the incident angle of the system having a cavity having a thickness of 300 nm according to the first embodiment of the present invention.

Fig. 2B is a graph showing the relationship between the reflectance and the incident angle of the system having a cavity having a thickness of 400 nm according to the first embodiment of the present invention.

Fig. 2C is a graph showing the relationship between the reflectance and the incident angle of the system having a cavity having a thickness of 520 nm according to the first embodiment of the present invention.

Fig. 3 is a plan view showing the arrangement relationship between the cavity and the bonding layer of the light-emitting element of the first embodiment of the present invention.

Fig. 4 is a plan view showing the arrangement relationship between a cavity and a bonding layer of a light-emitting element according to another embodiment of the present invention.

Fig. 5 is a graph showing the relationship between reflectance and wavelength of a light-emitting element having a different substance filled in a cavity according to a first embodiment of the present invention.

Figure 6 is a graph showing the relationship between reflectance and incident angle for a system having different materials filled in a cavity according to a first embodiment of the present invention.

Figure 7 is a cross-sectional view showing a light-emitting element of a second embodiment of the present invention.

Figure 8 is a cross-sectional view showing a light-emitting element of a third embodiment of the present invention.

Fig. 9 is a plan view showing the arrangement relationship between the cavity and the bonding layer of the light-emitting element of the third embodiment of the present invention.

Figure 10 is a cross-sectional view showing a light-emitting element of a fourth embodiment of the present invention.

The following embodiments will be described with reference to the drawings, in which the same or the same parts are used in the drawings, and in the drawings, the shape or thickness of the elements can be expanded. Big or small. It is to be noted that elements not shown or described in the specification may be in a form known to those skilled in the art.

Please refer to FIG. 1 , which is a cross-sectional view of a light-emitting device according to a first embodiment of the present invention. The light-emitting device includes a body 1 , a reflective structure 2 and a cavity 3 . The cavity 3 is located in the body 1 and the reflective structure 2 . between. The body 1 includes a light-emitting layer 11 and a transparent substrate 12. The transparent substrate 12 has a pair of upper surface 121 and a lower surface 122. The upper surface 121 and the lower surface 122 are respectively connected to the light-emitting layer 11 and the cavity 3. In other words, the transparent substrate 12 is closer to the cavity 3 than the light-emitting layer 11 , the transparent substrate 12 is located between the light-emitting layer 11 and the cavity 3 , and the cavity 3 is located between the transparent substrate 12 and the reflective structure 2 .

The light emitting laminate 11 includes a first type semiconductor layer 111, a second type semiconductor layer 112, and an active layer 113 between the first type semiconductor layer 111 and the second type semiconductor layer 112, and the first type semiconductor layer 111 The active layer 113 and the second semiconductor layer 112 are stacked on the upper surface 121 of the transparent substrate 12. The first semiconductor layer 111 and the second semiconductor layer 112 respectively have different first conductivity and second conductivity. To provide electrons and holes, respectively, or to provide holes and electrons, respectively; the active layer 113 may comprise a single heterostructure, a double heterostructure or a multiple quantum wells. The material of the first type semiconductor layer 111, the second type semiconductor layer 112, and the active layer 113 is a tri-five compound semiconductor, and may be, for example, GaAs, InGaAs, AlGaAs, AlInGaAs, GaP, InGaP, AlInP, AlGaInP, GaN, InGaN, AlGaN, AlInGaN, AlAsSh, InGaAsP, InGaAsN, AlGaAsP, and the like. In the present embodiment, unless otherwise specified, the chemical expressions include "chemically-accepting compounds" and "non-chemically-accepting compounds", wherein "chemically-accepting compounds" are, for example, total elements of a tri-family element. The dose is the same as the total elemental dose of the Group 5 element. Conversely, the "non-stoichiometric compound" such as the total elemental dose of the Group III element is different from the total elemental dose of the Group 5 element. For example, the chemical expression is AlGaAs, which means that the tri-group element aluminum (Al) and/or gallium (Ga), and the five-element element arsenic (As), of which the tri-group elements (aluminum and/or gallium) are total. The elemental dose may be the same as or different from the total elemental dose of the Group V element (arsenic). Further, if each of the compounds represented by the chemical expressions is a compound having a stoichiometric amount, AlGaAs represents Al _x Ga _(1-x) As, wherein 0 ≦ x ≦ 1; AlInP represents Al _x In _{(1-x )} P, wherein, 0 ≦ x ≦ 1; AlGaInP representative of _{(Al y Ga (1-y} )) 1-x In x P, wherein, 0 ≦ x ≦ 1,0 ≦ y ≦ 1; AlGaN Representative Al _x Ga _{( 1-x)} N, where 0≦x≦1; AlAsSb represents AlAs _x Sb _(1-x) , where 0≦x≦1; InGaP represents In _x Ga _1-x P, where 0≦x≦1 InGaAsP represents In _x Ga _1-x As _1-y P _y , where 0≦x≦1,0≦y≦1; InGaAsN represents In _x Ga _1-x As _1-y N _y , where 0≦x ≦1,0≦y≦1; AlGaAsP represents Al _x Ga _1-x As _1-y P _y , where 0≦x≦1,0≦y≦1; InGaAs represents In _x Ga _1-x As, wherein 0≦x≦1. In addition, the light emitting laminate 11 may have a roughened surface R1 in a direction away from the transparent substrate 12, for example, a roughened surface R1 on the upper surface of the second type semiconductor layer 112 to reduce the light emitted by the active layer 113 in the second The probability of total reflection occurs on the upper surface of the semiconductor layer 112, and the path of the emitted light is increased. The roughness of the roughened surface R1 may be, for example, less than 0.2 to 5 μm, and the roughness described herein is the difference in height between the highest point of the convex portion of the roughened surface R1 and the lowest point of the concave portion.

The energy gap of the material of the transparent substrate 12 is larger than the energy gap of the material of the active layer 113, so that the transparent substrate 12 has high transmittance to the light emitted by the active layer 113, for example, the transmittance is 90% or more, and the transparent substrate 12 is The material may be, but not limited to, transparent insulating materials such as sapphire, diamond, glass, quartz, Acryl, and epoxy resin (Alp). Or may be a transparent conductive oxide (TCO) such as zinc oxide (ZnO), indium tin oxide (ITO), indium zinc oxide (IZO), gallium oxide (Ga ₂ O ₃ ), lithium gallium oxide (LiGaO ₂ ), oxidation Lithium aluminum (LiAlO ₂ ) or magnesium aluminum oxide (MgAl ₂ O ₄ ), etc., or may be a semiconductor material such as SiC, GaAs, GaN, GaB, GaAsP ), zinc selenide (ZnSe), zinc selenide (ZnSe) or indium phosphide (InP). The light-emitting layer 11 can be grown on the transparent substrate 12 or a growth substrate by an epitaxial method such as metalorganic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE) or hydride vapor phase epitaxy (HVPE). The light-emitting laminate 11 formed on the growth substrate can be bonded to the transparent substrate 12 by the substrate transfer technique and the growth substrate can be removed. The light-emitting layer 11 of the light-emitting element of the present embodiment is directly grown on the transparent substrate 12, and a buffer layer 13 is disposed between the light-emitting layer 11 and the transparent substrate 12. The buffer layer 13 may comprise a polycrystalline or single crystal material, such as a buffer. The material of the layer 13 may include gallium nitride (GaN), aluminum nitride (AlN) or aluminum gallium nitride (AlGaN), etc., and the transparent substrate 12 and the light-emitting layer 11 may be reduced by transmitting the buffer layer 13 in the epitaxial process. Defects that occur when the grid does not match. Alternatively, in another embodiment, the light emitting laminate 11 is bonded to the upper surface 121 of the transparent substrate 12 through a substrate transfer technique, and the buffer layer 13 may be an adhesive layer to fix the light emitting laminate 11 on the transparent substrate 12. The material of the buffer layer 13 may include a transparent polymer material, oxide, nitride or fluoride, etc., in order to avoid blocking or absorbing light emitted from the light-emitting layer 11 in the direction of the transparent substrate 12. For example, the material of the buffer layer 13 may comprise alumina (Al ₂ O _3), silicon dioxide (SiO _2), indium tin oxide (ITO), indium zinc oxide (IZO), titanium oxide (TiO _2), thallium oxide (Ta ₂ O ₅ ), cerium oxide (TeO ₂ ), yttrium oxide (Y ₂ O ₃ ), cerium oxide (HfO ₂ ) or lithium niobate (LiNbO ₃ ). The upper surface 121 of the transparent substrate 12 has a patterned structure. Specifically, the height difference between the highest point of the convex portion of the patterned upper surface 121 of the transparent substrate 12 and the lowest point of the concave portion may be 0.2 to 5 μm to increase the light emission through the patterned structure. The light extraction rate of the component.

The body 1 of the present embodiment further includes a first electrode 14 and a second electrode 15 electrically connected to the first type semiconductor layer 111 and the second type semiconductor layer 112, respectively, and the first electrode 14 and the second electrode 15 are located The same side of the transparent substrate 12, for example, the first electrode 14 and the second electrode 15 of the light-emitting element of the present embodiment are located on the light-emitting laminate 11, so that the light-emitting element forms a horizontal type light-emitting junction. The body 1 has a recess R to expose a portion of the first semiconductor layer 111. The first electrode 14 is on the first semiconductor layer 111 of the recess R, and the second electrode 15 is on the second semiconductor 112. . The current of the external power source is injected into the light-emitting element through the first electrode 14 and the second electrode 15, and the electrons and the hole are combined with the active layer 113 by the external power source to generate light. In addition, the body 1 may include a protective layer P covering the light emitting laminate 11 and exposing the first electrode 14 and the second electrode 15. The first electrode 14 and the second electrode 15 comprise a high conductivity material and may each comprise a plurality of layers. The material of the first electrode 14 and the second electrode 15 may comprise, for example, a transparent conductive material or a metal material. For example, transparent conductive materials include, but are not limited to, indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO). , zinc tin oxide (ZTO), gallium zinc oxide (GZO), zinc oxide (ZnO), gallium phosphide (GaP), indium zinc oxide (IZO), diamond-like carbon film (DLC), indium gallium oxide (IGO), Gallium aluminum zinc oxide (GAZO) or a compound of the above materials; metal materials include, but are not limited to, aluminum (Al), chromium (Cr), copper (Cu), tin (Sn), gold (Au), nickel (Ni), titanium (Ti), platinum (Pt), lead (Pb), zinc (Zn), cadmium (Cd), antimony (Sb), cobalt (Co) or an alloy of the above materials.

As shown in FIG. 1, the reflective structure 2 is located between a top surface 41 of a carrier 4 and a lower surface 122 of the transparent substrate 12, and the reflective structure 2 can directly interface with the cavity 3. The carrier 4 may be a ceramic substrate, a conductive support, a printed circuit board, or other structure formed of a conductive material, a semiconductor material, or an insulating material. The reflective structure 2 has a surface 2a facing the lower surface 122 of the transparent substrate 12, and the reflective structure 2 includes a reflective layer 21 including a plurality of first reflective layers 211 and a plurality of second reflective layers 212, and a plurality of A reflective layer 211 and a plurality of second reflective layers 212 are stacked one on another. The first reflective layer 211 and the second reflective layer 212 each have different materials and refractive indices, and the materials of the first reflective layer 211 and the second reflective layer 212 include a conductive material, a dielectric material, or a tri-five semiconductor material. The conductive material may be, for example, indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), zinc oxide (ZnO), aluminum zinc oxide. (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO) or indium zinc oxide (IZO); dielectric materials such as magnesium oxide (MgO), SU8, benzocyclobutene (BCB), perfluorination Cyclobutane (PFCB), epoxy resin (Epoxy), acrylic resin (Acrylic Resin), cycloolefin polymer (COC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET) , Polyimine (PI), Polycarbonate (PC), Polyetherimide, Fluorocarbon Polymer, Glass, Ta ₂ O ₅ , Alumina (Al ₂ O ₃ ), cerium oxide (SiO ₂ ), titanium oxide (TiO ₂ ), cerium nitride (SiN _x ), spin-on glass (SOG) or tetraethoxy decane (TEOS); Material example May be aluminum gallium arsenide (AlGaAs), aluminum gallium indium phosphide (AlGaInP), gallium nitride (GaN), gallium phosphide (GaP) and the like. When the material of the first reflective layer 211 and/or the second reflective layer 212 is a tri-five semiconductor, the element composition in the tri-five semiconductor may be adjusted, or the first reflective layer 211 and the second reflective layer 212 may be changed. The thickness of the reflective laminate 21 is such that it reflects the wavelength of the light to be reflected. In another embodiment, the first reflective layer 211 or the second reflective layer 212 formed by the dielectric material having a high refractive index has a thinner thickness than other reflective layers formed of a dielectric material having a low refractive index. For example, the refractive index of the first reflective layer 211 is higher than the refractive index of the second reflective layer 212, and the thickness of the first reflective layer 211 is smaller than the thickness of the second reflective layer 212. In addition, the thicknesses of the first reflective layer 211 and the second reflective layer 212 may conform to the following formulas (1) and (2), wherein the first reflective layer 211 has a first thickness t ₁ and a first refractive index n ₁₁ The second reflective layer 212 has a second thickness t2 and a second refractive index n ₁₂ : t ₁ =m(λ/4n ₁₁ )..... Formula (1)

t ₂ =m(λ/4n ₁₂ ).....formula (2)

Where m is a positive integer and λ is the wavelength to be reflected by the reflective structure 2. For example, the first reflective layer 211 of the present embodiment is titanium dioxide, having a first refractive index n ₁₁ of 2.6, and the second reflective layer 212 is ceria having a second refractive index n ₁₂ of 1.46. Structure 2 achieves a good reflection effect on the emitted light having a wavelength of 450 nm, and the first thickness t ₁ may be 43 nm or a multiple thereof, and the second thickness t2 may be 77 nm or a multiple thereof. However, in order to increase the wavelength range in which the reflective structure 2 has high reflectivity, the plurality of first reflective layers 211 may each selectively have different thicknesses. Similarly, the plurality of second reflective layers 212 may also selectively have different thicknesses, respectively. This is not a limit.

The first reflective layer 211 of the present embodiment is titanium dioxide (TiO ₂ ), the second reflective layer 212 is cerium oxide (SiO ₂ ), and the plurality of first reflective layers 211 each have the same thickness of 30 nm to 60 nm, and the second plurality of reflections The layers 212 also have the same thickness of 50 nm to 90 nm, and the thickness of each of the first reflective layer 211 and each of the second reflective layers 212 preferably conforms to the above formulas (1) and (2). The number of layers of the plurality of first reflective layers 211 and the plurality of second reflective layers 212 is 3-10 layers, respectively, and the plurality of first reflective layers 211 and the plurality of second reflective layers 212 overlap each other to form a reflective laminate 21, that is, The cavity 3 faces the top surface 41 of the carrier 4 in a structure in which the first reflective layer 211, the second reflective layer 212, the first reflective layer 211, and the second reflective layer 212 are alternately stacked. The reflective structure 2 can also optionally include a metal reflective layer 22 under the reflective layer 21, that is, the reflective layer 21 is located between the cavity 3 and the metal reflective layer 22, so that the reflective layer 21 and the metal reflective layer 22 are common. An omni-directionally reflector is formed. The light that is not reflected by the interface between the transparent substrate 12 and the cavity 3 can be reflected by the reflective structure 2 back to the transparent substrate 12 through the reflective structure 2, thereby further increasing the external quantum efficiency of the light-emitting element (External Quantum Efficiency). The metal reflective layer 22 has a thickness of, for example, 50 nm to 200 nm, and the metal reflective layer 22 may include a plurality of sub-layers each having a different metal material, and the material of the metal reflective layer 22 may include, for example, copper (Cu), aluminum (Al), and tin. (Sn), gold (Au), silver (Ag), lead (Pb), titanium (Ti), nickel (Ni), platinum (Pt), tungsten (W), germanium (Ge) or an alloy of the above materials. In addition, as shown in FIG. 1, the reflective structure 2 may include a connection layer 23 on the last layer of the reflective layer 21 (the second reflection layer 212 which is the farthest from the cavity 3 in this embodiment) and the metal reflection layer 22 In order to increase the bonding force between the reflective laminate 21 and the metal reflective layer 22, the connection layer 23 may be, for example, aluminum oxide (Al ₂ O ₃ ). In another embodiment, the last layer of the reflective layer 21 is the first reflective layer 211, and the first reflective layer 211 is connected to the metal reflective layer 22 through the connecting layer 23. The thickness of the connecting layer 23 may be 1 nm to 50 nm. .

The cavity 3 is located between the transparent substrate 12 and the reflective structure 2, wherein the transparent substrate 12 can directly contact the cavity 3, so that light can be reflected through the interface between the transparent substrate 12 and the cavity 3, and the transparent substrate 12 is The side edges are ejected or returned to the light emitting stack 11; and the cavity 3 can also be directly connected to the reflective structure 2, so that the light energy penetrating the cavity 3 can be reflected by the reflective structure 2, further increased by the transparent substrate 12-cavity 3- The reflectivity of the system formed by the reflective structure 2 to the light emitted by the light-emitting stack 11. As shown in FIG. 1, the cavity 3 of the present embodiment has a thickness T which is the shortest distance between the lower surface 122 of the transparent substrate 12 and the surface 2a of the reflective structure 2 in the direction of the transparent substrate 12 toward the reflective structure 2. Wherein the thickness T is between 200 nm and 800 nm, or may be not less than 400 nm, and when the light-emitting element has the cavity 3 having a thickness T of not less than 400 nm, the light emitted by the light-emitting layer 11 can be increased on the transparent substrate 12, the cavity 3 and the reflective capability of the system formed by the reflective structure 2. Please refer to FIGS. 2A-2C for the relationship between the reflectivity and the incident angle of the light of the transparent substrate 12-cavity 3-reflecting structure 2 of the cavity 3 having different thicknesses T, wherein the thickness of the cavity 3 is T is 300 nm (Fig. 2A), 400 nm (Fig. 2B), and 520 nm (Fig. 2C). The incident light has a wavelength of 450 nm. It can be observed from the figure that when the thickness T is greater than 400 nm, the incident angle is 40 to 70 degrees. The reflectance in the range is greatly improved, and when the thickness T is raised to 520 nm, the incident light for the full angle (ie, 0 to 90 degrees) is almost 100% reflectance, and the thickness of the cavity 3 is apparent. T can be greater than 400 nm, or can be greater than 520 nm to increase the range of incident angles with high reflectivity response.

Further, the transparent substrate 12, the light-emitting stack 11 emit light having a third refractive index _{n. 3,} the cavity 3 and the light-emitting stack 11 emit light having a fourth refractive index _{n. 4,} wherein the third refractive index n _{3 is} greater than the fourth refractive index n ₄ , and the cavity 3 may be vacuum or filled with a substance. If the cavity 3 is filled with a substance, the refractive index of the light emitted by the substance to the light-emitting layer 11 is the fourth refractive index. n ₂ . For example, when sapphire (refractive index of about 1.76 to 1.78) is used as the material of the transparent substrate 12, the substance in the cavity 3 may be selected to include air, nitrogen, magnesium fluoride (MgF ₂ ), aluminum fluoride (AlF ₃ ) or Cerium oxide (SiO ₂ ) or the like. In this case, the third refractive index n ₃ is about 1.76 to 1.78, and the fourth refractive index n ₂ is about 1.0, 1.0, 1.38, 1.38, 1.46, respectively, when the light emitted by the light emitting laminate 11 is directed toward the transparent substrate. When the direction of 12 is advanced, the light may be totally reflected at the interface between the transparent substrate 12 and the cavity 3, and the light may be emitted from the side of the transparent substrate 12 to the outside or returned and separated from the transparent substrate 12 by the light-emitting layer 11. The side emits light, thereby increasing the light extraction rate of the light-emitting element. In different embodiments, in order to make the interface between the transparent substrate 12 and the cavity 3 susceptible to total reflection, the difference between the third refractive index n ₃ and the fourth refractive index n ₄ may be not less than 0.33, or may be between 0.35 and 0.9. Or may be between 0.38 and 0.78, so that the specific difference between the third refractive index n ₃ and the fourth refractive index n ₄ may contribute to an improvement in light extraction efficiency of the light-emitting element.

The carrier 4 is used to support the reflective structure 2, and the implementation of the carrier 4 may include a ceramic substrate, a conductive support or a PCB board, etc., but should not be limited thereto. As shown in FIG. 1, the carrier 4 of the present embodiment has an opposite top surface 41 and a bottom surface 42, wherein the distance between the top surface 41 and the lower surface 122 of the transparent substrate 12 is smaller than the distance between the bottom surface 42 and the lower surface 122, and at least The shape of the partial cavity 3 can be defined by the surface topography of the top surface 41 of the carrier 4. For example, the top surface 41 of the carrier 4 can be recessed toward the bottom surface 42, and the position of the recess is correspondingly located below the transparent substrate 12, and the reflection The structure 2 is located on the top surface 41 of the carrier 4, and the metal reflective layer 22 and the reflective layer 21 of the reflective structure 2 are sequentially stacked on the top surface 41 of the carrier 4, so that the reflective structure 2 is formed on the carrier 4 according to the shape of the top surface 41. Above, the reflective structure 2 has a recess 24 recessed toward the bottom surface 42 , and the recess 24 is correspondingly located below the transparent substrate 12 and is located at the light emitting layer 11 In the path of the passage, the pocket 24 can form at least a portion of the cavity 3. In addition, the carrier 4 is provided with a first guiding portion 43 and a second guiding portion 44 electrically connected to the first electrode 14 and the second electrode 15, respectively, and the first guiding portion 43 and the second guiding portion 44 are located On the surface 2a of the reflective structure 2 or on the carrier 4, a face-up wire bond process, a flip chip bond process or other bonding process is used to pass through the first connector E1. The first electrode 14 is electrically connected to the first guiding portion 43 and the second electrode 15 is electrically connected to the second guiding portion 44 through a second connecting member E2. In one embodiment, the first guiding portion 43 and the second guiding portion 44 penetrate the reflective structure 2 such that at least a portion of the surfaces of the first guiding portion 43 and the second guiding portion 44 are not covered by the reflective structure 2 Exposed, the first electrode 14 and the second electrode 15 are electrically connected to each other through a subsequent bonding process. The first connecting member E1 and the second connecting member E2 can be exemplified by metal wires, metal or alloy solders, or other conductive rubber materials. In addition, the reflective structure 2 of the present embodiment is located on the carrier 4 and has a peripheral edge 2E. The peripheral edge 2E of the reflective structure 2 is located on the outer side of the peripheral edge 12E of the transparent substrate 12 so that the reflective structure 2 is formed. There is sufficient space for the first guiding portion 43 and the second guiding portion 44 to be disposed thereon, and the corresponding position is located outside the transparent substrate 12. In detail, the first guiding portion 43 and the second guiding portion 44 are located between the peripheral edge 2E and the peripheral edge 12E (not shown), so as to facilitate the subsequent engagement of the carrier through the dressing and wire bonding process. The first guiding portion 43 and the second guiding portion 44 of the fourth electrode and the first electrode 14 and the second electrode 15 of the body 1.

As shown in FIG. 1, the body 1 of the present embodiment is disposed above the carrier 4 and coupled to the carrier 4 through a bonding layer 5, wherein the bonding layer 5 has a function similar to the upper layer of the pad. The bonding layer 5 is located on the lower surface 122 of the transparent substrate 12 and correspondingly surrounds the upper edge of the recess 24, and the outer edge of the bonding layer 5 can be close to or aligned with one side 12E of the transparent substrate 12, or the bonding layer 5 is along the transparent substrate. 12 edge settings. In addition, the cavity 3 is formed by the lower surface 122 of the transparent substrate 12, the bonding layer 5, and the reflective structure 2, which may be A closed or non-closed space. The material of the bonding layer 5 may use a substance having a transmittance of 90% or more for the light emitted from the active layer 113, so that the light toward the reflective structure 2 is not blocked or absorbed by the bonding layer 5, and can penetrate the bonding layer 5 to be The reflective structure 2 under the bonding layer 5 is further reflected, thereby increasing the light extraction rate of the light-emitting element. For example, if the bonding layer 5 is transparent (ie, the transmittance of the light emitted from the light-emitting layer 11 is 90% or more), the material of the bonding layer 5 may be selected from benzocyclobutene (BCB). Epoxy, spin-on glass (SOG), polyimide, perfluorocyclobutane (PFCB), Su8, acrylic resin (Acrylic Resin), polymethyl methacrylate (PMMA) a group consisting of polyethylene terephthalate (PET), polycarbonate (PC), polyetherimide, and fluorocarbon polymer, and bonded in one embodiment. The layer 5 can also add a heat conductive agent such as boron nitride (BN) or aluminum nitride (AlN) to the colloid formed by the above materials, so that the heat generated when the body 1 operates can be conducted and transmitted through the bonding layer 5. In another embodiment, the material of the bonding layer 5 may also be a substance having a reflectance of 90% or more for the light emitted from the light emitting layer 11, and may be, for example, selected from the group consisting of metals such as gold, silver, aluminum, chromium, tin, and titanium. The group includes gold tin alloy or tin silver copper alloy, etc., so that the light toward the reflective structure 2 can be partially reflected back to the transparent substrate 12 by the bonding layer 5, and light is emitted from the side surface of the transparent substrate 12, thereby increasing the light of the light emitting element. Takeout rate.

In addition, as shown in FIG. 1 and FIG. 3, the light-emitting element of the first embodiment of the present invention can be selectively provided with a baffle M between the lower surface 122 of the transparent substrate 12 and the reflective structure 2, wherein the baffle M has a first opening O1 corresponding to the lower side of the transparent substrate 12, so that the first opening O1 is disposed at the position where the recess 24 is open, thereby isolating the bonding layer 5 and the cavity 3, so that the cavity 3 is located on the transparent substrate 12, Between the reflective structure 2 and the baffle M, it is possible to prevent the material of the bonding layer 5 from being pressed and moved into the cavity 3 when the body 1 and the reflective structure 2 are joined by the bonding layer 5. The material of the baffle M is selected to have a pair of light emitting laminates 11 A material that emits light with high transparency (more than 90% penetration) or high reflectance (reflectance of more than 90%), such as Epoxy, glass or plastic. In another embodiment, the baffle M includes a first baffle M1 and a second baffle M2. The first baffle M1 forms the first opening O1, and the second baffle forms a second opening O2. The area of the second opening O2 is larger than the area of the first opening O1, and the first baffle M1 is located in the second opening O2, so that the bonding layer 5 is sandwiched between the first baffle M1, the second baffle M2, the transparent substrate 12, and the reflection In the space formed by the structure 2, the material of the bonding layer 5 is prevented from being forced to move toward the cavity 3 or to protrude from the side of the transparent substrate 12. By the arrangement of the shutter M, the bonding layer 5 can be formed at a predetermined position, and the thickness of the cavity 3 can be precisely controlled. Referring to FIG. 3, in the present embodiment, the bonding layer 5 is continuously located on the outer periphery of the cavity 3. However, the form of the bonding layer 5 is not limited thereto, and in the embodiment shown in FIG. 4, the bonding layer 5 is discontinuous and includes a plurality of bonding layer portions 5' which are cavities 3 is a symmetry center arranged around the cavity 3, wherein the baffle M has a plurality of second openings O2 symmetrically, and the shape of the second opening O2 is a shape to be formed by the bonding layer portion 5'. The joint layer portions 5' are symmetrical to each other to the cavity 3.

Referring to Fig. 5, this is a graph showing the relationship between the reflectance and the wavelength of the light-emitting element of the first embodiment of the present invention. The cavity 3 of the light-emitting element shown by the line 5A is filled with air having a refractive index of 1, and the cavity 3 of the light-emitting element of the line 5B is filled with cerium oxide having a refractive index of 1.46, and the light-emitting elements of the lines 5A and 5B. The refractive index of the transparent substrate 12 is 1.76 to 1.78. Therefore, as described above, the difference between the third refractive index n ₃ and the fourth refractive index n ₄ of the light-emitting element of the line 5A is 0.76 to 0.78, and the light-emitting element of the line 5B The difference between the third refractive index n ₃ and the fourth refractive index n ₄ is 0.3 to 0.32. As can be seen from the figure, in the interval of 430 nm to 550 nm, the reflectance of the light-emitting element of the line 5A is higher than that of the light-emitting element of the line 5B, and particularly, the difference in reflectance between the regions of 430 nm and 470 nm is more remarkable. That is, the light-emitting element in which the cavity 3 is filled with air has a higher reflectance than the light-emitting element in which the cavity 3 is filled with cerium oxide in a wavelength range. In addition, please refer to FIG. 6 again, which is a system for the transparent substrate 12-cavity 3-reflecting structure 2 filling the cavity 3 of different substances, and measuring the relationship between the reflectivity of the system and the incident angle of the light, Among them, the substances filled in the cavity 3 are air (line 6A), magnesium fluoride (line 6B) and cerium oxide (line 6C). It can be seen from Fig. 6 that the system in which the cavity 3 is filled with air has a reflectance higher than 97% for incident light having an incident angle of 35 to 62 degrees, and the reflection effect is better than that of the cavity 3 filled with magnesium fluoride and dioxide. The system of 矽. When the substance filled in the cavity 3 is magnesium fluoride, the system has a higher reflectance at an incident angle of 53 to 54 degrees and 60 to 61 degrees than a system in which the cavity 3 is filled with cerium oxide.

Referring to FIG. 7, which is a cross-sectional view of a light-emitting element according to a second embodiment of the present invention, the material of each member of the light-emitting element of the present embodiment and the connection relationship between the members are substantially similar to those of the light-emitting element of the foregoing embodiment. Or the same, the difference is that at least a portion of the shape of the cavity 3 of the present embodiment is defined by the surface topography of the lower surface 122 of the transparent substrate 12. In detail, the transparent substrate 12 of the present embodiment has a concave portion 123 facing the reflective structure 2 to constitute at least a portion of the cavity 3, wherein the concave portion 123 is directed from the lower surface 122 of the transparent substrate 12 toward the light emitting laminate 11. The recess is formed, and the top surface 41 of the carrier 4 is a flat surface. The bonding layer 5 is located between the transparent substrate 12 and the reflective structure 2 and can surround the opening of the recess 123. The cavity 3 is located in the recess 123 of the transparent substrate 12 and the bonding layer 5. And between the reflective structures 2. In another embodiment, the top surface 41 of the carrier 4 may also have a recess 24 as shown in the first embodiment, such that the cavity 3 is located in the recess 24 of the reflective structure 2, the recess 123 of the transparent substrate 12, and the bonding layer. Between 5

Referring to FIG. 8, a cross-sectional view of a light-emitting element according to a third embodiment of the present invention, the material of each member of the light-emitting element of the present embodiment and the connection relationship between the members are substantially the same as those of the foregoing embodiments. Similar or identical, the difference is that the light-emitting element of the present embodiment has a gap between the transparent substrate 12 and the reflective structure 2 by the bonding layer 5. In detail, in the embodiment, the surface 2a of the reflective structure 2 and the lower surface 122 of the transparent substrate 12 are both flat surfaces, and the bonding layer 5 has a function similar to the upper layer of the pad. In detail, the bonding layer 5 is on the surface 2a to The lower surface 122 has a thickness T in the direction to separate the lower surface 122 of the transparent substrate 12 from the surface 2a of the reflective structure 2 to a distance T having a thickness T such that the cavity 3 is disposed on the lower surface of the transparent substrate 12. 122. Between the reflective structure 2 and the bonding layer 5. As shown in FIG. 9, the bonding layer 5 is located at a central position of the lower surface 122 of the transparent substrate 12, and the cavity 3 surrounds the bonding layer 5 such that the cavity 3 is located between the edge 12E of the transparent substrate 12 and the bonding layer 5. The cavity 3 is a gap between the transparent substrate 12 and the reflective structure 2. The feature of this embodiment is that the cavity 3 surrounds the bonding layer 5 so that the cavity 3 directly communicates with the external environment, so when the substance filled in the cavity 3 has a high coefficient of thermal expansion (CTE), for example, : When the material has a thermal expansion coefficient greater than 10 ^-4 K ^-1 at room temperature (about 293 K), the light-emitting element is not easily damaged by the temperature variation of the operating environment, and the damage is caused by the shrinkage of the material. The volume change of the substance is excessively large, and the influence of the bonding layer 5 in combination with the body 1 and the reflective structure 2 is weakened.

Referring to FIG. 10, which is a cross-sectional view of a light-emitting element according to a fourth embodiment of the present invention, the material of each member of the light-emitting element of the present embodiment and the connection relationship between the members are substantially the same as those of the foregoing embodiments. Similar or identical, but the bonding layer 5 can be optionally omitted. The main difference between the present embodiment and the foregoing embodiments is that the first electrode 14 and the second electrode 15 are located between the light-emitting layer 11 and the reflective structure 2, and the first electrode 14 and the second electrode 15 are electrically connected to the first electrode, respectively. The semiconductor layer 111 and the second semiconductor layer 112. Specifically, the transparent substrate 12 of the present embodiment is a conductive substrate, but is not limited thereto. Further, the body 1 may selectively include a buffer layer 13 having conductivity. The first type semiconductor layer 111 is electrically connected to the first electrode 14 through the conductive buffer layer 13 and the transparent substrate 12, and further, the body 1 Further, a conductive path 16 is included to electrically connect the second electrode 15 to the second type semiconductor layer 112 through the conductive path 16 . In order to prevent leakage, the body 1 is further provided with an insulating coating layer 17 covering the periphery of the conductive path 16. In detail, the insulating coating layer 17 is located on the active layer 113, the first type semiconductor layer 111, the buffer layer 13, and the transparent layer. Between the substrate 12 and the conductive path 16, the conductive path 16 is electrically insulated from the above layers (ie, 113, 111, 13, 12).

The carrier 4 of the present embodiment is the same as the foregoing embodiments, and includes a first guiding portion 43 and a second guiding portion 44. The first guiding portion 43 and the second guiding portion 44 are located on the surface 2a of the reflective structure 2, The first electrode 14 and the second electrode 15 of the body 1 are disposed on the first guiding portion 43 and the second guiding portion 44 of the carrier 4, and are formed of a material such as solder or conductive adhesive to form the first connecting member E1 and the second connecting member. E2, the first connecting member E1 is located between the first electrode 14 and the first guiding portion 43 to electrically connect the two, and the second connecting member E2 is located at the second electrode 15 and the second guiding portion 44. The two are electrically connected. The material of the first connecting member E1 and the second connecting member E2 may include tin, antimony, indium, or an alloy composed of two or more of tin, antimony, and indium. The cavity 3 of the embodiment is located on the light emitting laminate 11 , the reflective structure 2 , the first electrode 14 , the second electrode 15 , the first guiding portion 43 , the second guiding portion 44 , the first connecting member E1 and the second connection Between the pieces E2, the first guiding portion 43, the first connecting member E1 and the first electrode 14 of the embodiment have the function of the upper layer, and the three are sequentially stacked in the direction of the surface 2a of the vertical reflecting structure 2. On the surface 2a, the transparent substrate 12 is raised to form the cavity 3 of the thickness T between the lower surface 122 of the transparent substrate 12 and the surface 2a of the reflective structure 2, so that the light-emitting element of the embodiment can be selectively omitted. Layer 5. Similarly, the cavity 3 may be filled with a substance which may be selected to be transparent to the emitted light of the light-emitting stack 11 and having a refractive index to the emitted light (ie, the fourth refractive index n ₄ ) smaller than the third refractive index of the transparent substrate 12 . Rate n ₃ material, and increase the heat dissipation efficiency of the light-emitting element through the substance in the cavity 3. In this embodiment, the transparent material is filled in the cavity 3, thereby providing the function of supporting the light-emitting element to make the light The structural strength of the component is thereby increased.

It is to be noted that the various embodiments of the present invention are intended to be illustrative only and not to limit the scope of the invention. Any obvious modifications or variations of the present invention are possible without departing from the spirit and scope of the invention. The same or similar components in different embodiments, or components having the same reference numbers in different embodiments, have the same physical or chemical properties. In addition, the above-described embodiments of the present invention may be combined or substituted with each other as appropriate, and are not limited to the specific embodiments described. The connection between the specific components and the other components described in detail in the embodiments can also be applied to other embodiments, and all fall within the scope of the scope of the invention as described hereinafter.

Claims (10)

A light emitting device comprising: a transparent substrate; a light emitting laminate; a reflective structure, wherein the transparent substrate is located between the light emitting laminate and the reflective structure; and a cavity between the transparent substrate and the reflective structure Wherein the transparent substrate faces a direction of the reflective structure with a recess to form at least a portion of the cavity. The light-emitting element of claim 1, further comprising a carrier, wherein the reflective structure is located on the carrier. The illuminating device of claim 1, further comprising a first electrode and a second electrode, wherein the luminescent layer comprises a first type semiconductor layer, a second type semiconductor layer and an active layer Between the first type semiconductor layer and the second type semiconductor layer, the first electrode is electrically connected to the first type semiconductor layer and the second electrode is electrically connected to the second type semiconductor layer, the first An electrode and the second electrode are located between the light emitting stack and the reflective structure. The light-emitting element of claim 1, wherein the reflective structure comprises a reflective laminate, the reflective laminate comprising a plurality of first reflective layers and a plurality of second reflective layers interleaved with each other, the first reflective layer and The second reflective layer has a different refractive index. The light-emitting element of claim 1, wherein the transparent substrate has a first refractive index, the cavity has a second refractive index, the first refractive index is greater than the second refractive index, and the first The difference between a refractive index and the second refractive index is between 0.38 and 0.78. A light-emitting element comprising: a transparent substrate; a light-emitting layer; a reflective structure, wherein the transparent substrate is located between the light-emitting layer and the reflective structure; a cavity between the transparent substrate and the reflective structure; And a bonding layer between the transparent substrate and the reflective structure, the bonding layer having a first bonding layer portion and a second bonding layer portion separated from the first bonding layer portion. The illuminating element of claim 6, wherein the first bonding layer portion and the second bonding layer portion are symmetrical to the cavity. The light-emitting element of claim 6, wherein the first bonding layer portion and the second bonding layer portion surround the cavity. A light-emitting element comprising: a transparent substrate having a first width; a light-emitting layer; a reflective structure, wherein the transparent substrate is located between the light-emitting layer and the reflective structure; a bonding layer located on the transparent substrate and The reflective structure has a second width therebetween, wherein the second width is smaller than the first width; and a cavity is located between the transparent substrate, the bonding layer and the reflective structure. The light-emitting element of claim 9, wherein the cavity surrounds the bonding layer.