TW202201817A - Light-emitting device - Google Patents

Abstract

A light-emitting device includes a substrate; a semiconductor stack capable of emitting a light having a peak wavelength λ, located on the substrate; and a light field adjustment layer located on the substrate or the semiconductor stack, wherein the light field adjustment layer includes a plurality of first layers and a plurality of second layers alternately stacked on top of each other, each of the plurality of first layers includes a first optical thickness, and each of the plurality of second layers includes a second optical thickness.

Description

light-emitting element

The present invention relates to a light-emitting element, and in particular, to a light-emitting element comprising a light field adjustment layer.

Light-Emitting Diode (LED) is a solid-state semiconductor light-emitting element, which has the advantages of low power consumption, low heat generation, long working life, shock resistance, small size, fast response speed and good optoelectronic properties, such as stable emission wavelength. Therefore, light-emitting diodes are widely used in household appliances, equipment indicator lights, and optoelectronic products.

According to an embodiment of the present invention, a light-emitting element is disclosed, which includes a substrate; a semiconductor stack capable of emitting a light having a peak wavelength λ on the substrate; and a light field adjustment layer on the substrate or the semiconductor layer, wherein the light The field adjustment layer includes a plurality of first layers and a plurality of second layers alternately stacked on top of each other, each of the plurality of first layers includes a first optical thickness, and each of the plurality of second layers includes a second optical thickness.

According to an embodiment of the present invention, the first optical thickness is less than 0.25λ, and the second optical thickness is greater than or approximately equal to 0.25λ.

According to an embodiment of the present invention, the first optical thickness is substantially equal to 0.25λ, and the second optical thickness is less than or greater than 0.25λ.

According to an embodiment of the present invention, the first optical thickness is greater than 0.25λ, and the second optical thickness is less than or approximately equal to 0.25λ.

According to another embodiment of the present invention, a light-emitting element is disclosed, which includes a substrate; a semiconductor stack capable of emitting a light with a peak wavelength λ, located on the substrate; and a light field adjustment layer located on the substrate or the semiconductor layer, wherein The light field adjustment layer includes a plurality of first layers, a plurality of second layers, and a space layer located between two adjacent first layers or between two adjacent second layers, wherein the space The layer contains an even multiple of 0.25+/-0.025λ in optical thickness.

In order to make the description of the present invention more detailed and complete, please refer to the description of the following embodiments and cooperate with the relevant figures. However, the embodiments shown below are for illustrating the light-emitting element of the present invention, and the present invention is not limited to the following embodiments. In addition, the dimensions, materials, shapes, relative arrangements, etc. of the constituent parts described in the embodiments are not limited to the description, and the scope of the present invention is not limited to these, but is merely a description. In addition, the size and positional relationship of the components shown in the drawings may be exaggerated for the sake of clarity. Furthermore, in the following description, in order to appropriately omit the detailed description, the same names and symbols are used for the same or similar components.

FIG. 1 is a side view of a light-emitting device 1 disclosed in an embodiment of the present invention. FIG. 2 is an emission spectrum diagram of a light-emitting element 1 according to an embodiment of the present invention. FIG. 2A is a partial enlarged view of the area A of FIG. 1 according to an embodiment of the present invention. FIG. 2B is a partial enlarged view of the area A of FIG. 1 according to another embodiment of the present invention.

As shown in FIG. 1, a light-emitting element 1 includes a substrate 10; a semiconductor stack 20 is located on the substrate 10, including a first semiconductor layer 21, a second semiconductor layer 22 and an active layer 23 located on the first semiconductor layer Between the layer 21 and the second semiconductor layer 22 ; a transparent conductive layer 40 on the semiconductor stack 20 ; a protective layer 50 covering the semiconductor stack 20 ;

The substrate 10 may be a growth substrate for epitaxially growing the semiconductor stack 20 . The substrate 10 includes a gallium arsenide (GaAs) wafer for epitaxial growth of aluminum gallium indium phosphide (AlGaInP), or a gallium nitride (GaN), indium gallium nitride (InGaN), or aluminum gallium nitride (InGaN) wafer for epitaxial growth. AlGaN) sapphire (Al ₂ O ₃ ) wafer, gallium nitride (GaN) wafer, silicon carbide (SiC) wafer or aluminum nitride (AlN) wafer.

The substrate 10 includes a first surface 101 and a second surface 102 . In this embodiment, the first surface 101 is the main light emitting surface of the light emitting element 1 . The light field adjustment layer 30 is disposed on the first surface 101 of the substrate 10, and has the function of selectively reflecting and penetrating a light having a peak wavelength λ emitted by the semiconductor stack 20, so that the transmittance of the light is affected by the incident light. The light field distribution of the light-emitting element 1 can be adjusted by changing the angle of the light-emitting element 1 . As shown in FIG. 2 , the semiconductor stack 20 of the light-emitting element 1 emits a light beam ranging from 430 nm to 470 nm, wherein the peak wavelength λ is the wavelength relative to the maximum light intensity, such as 450 nm.

The substrate 10 is in contact with the semiconductor stack 20 via the second surface 102 . The second side 102 may be a roughened surface. Roughened surfaces include surfaces with irregular morphology or surfaces with regular morphology. For example, with respect to the second surface 102 , the substrate 10 includes one or more protrusions (not shown) protruding from the second surface 102 , or includes one or more recesses (not shown) recessed in the second surface 102 . In a cross-sectional view, the convex portion (not shown) or the concave portion (not shown) may be in a semicircular shape or a polygonal shape.

In one embodiment of the present invention, by metalorganic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), hydride vapor deposition (HVPE), physical vapor deposition (PVD) or ion The electroplating method is used to form a semiconductor stack 20 having optoelectronic properties, such as a light-emitting stack, on the substrate 10 , wherein the physical vapor deposition method includes sputtering or evaporation.

The semiconductor stack 20 includes a first semiconductor layer 21 , a second semiconductor layer 22 , and an active layer 23 formed between the first semiconductor layer 21 and the second semiconductor layer 22 . The wavelength of light emitted by the light-emitting element 1 can be adjusted by changing the physical and chemical composition of one or more layers in the semiconductor stack 20 . The material of the semiconductor stack 20 includes III-V semiconductor materials, such as AlxInyGa(1- _{xy )} N, _AlxGa (1- _{x )} As or _AlxInyGa (1- _{xy )} P, wherein 0≦x, y≦1; (x+y)≦1. When the material of the semiconductor stack 20 is AlGaAs or AlInGaP series material, it can emit red light with wavelengths between 610 nm and 650 nm, or green light with wavelengths between 530 nm and 570 nm. When the material of the semiconductor stack 20 is InGaN series material, it can emit blue light or deep blue light with wavelengths between 400 nm and 490 nm, or green light with wavelengths between 490 nm and 550 nm. When the material of the semiconductor stack 20 is AlGaN series or AlInGaN series material, ultraviolet light with wavelengths between 250 nm and 400 nm can be emitted.

The first semiconductor layer 21 and the second semiconductor layer 22 can be cladding layers, and the two have different conductivity types, electrical properties, polarities, or provide electrons or holes according to doped elements, such as the first semiconductor layer. The first semiconductor layer 21 is an n-type semiconductor, and the second semiconductor layer 22 is a p-type semiconductor. The active layer 23 is formed between the first semiconductor layer 21 and the second semiconductor layer 22 . Electrons and holes are recombined in the active layer 23 driven by a current to convert electrical energy into light energy to emit light. The active layer 23 can be a single heterostructure (SH), a double heterostructure (DH), a double-side double heterostructure (DDH), or a multi-quantum well structure (multi-quantum) well, MQW). The material of the active layer 23 can be a neutral, p-type or n-type semiconductor. The first semiconductor layer 21 , the second semiconductor layer 22 , or the active layer 23 may be a single layer or a structure including a plurality of layers.

In an embodiment of the present invention, the semiconductor stack 20 may further include a buffer layer (not shown) between the first semiconductor layer 21 and the substrate 10 to release the material between the substrate 10 and the semiconductor stack 20 . The stress caused by lattice mismatch can reduce misalignment and lattice defects, thereby improving the quality of epitaxy. The buffer layer can be a single layer or a structure including multiple layers. In one embodiment, PVD aluminum nitride (AlN) can be selected as a buffer layer formed between the semiconductor stack 20 and the substrate 10 to improve the epitaxial quality of the semiconductor stack 20 . In one embodiment, the target used to form PVD aluminum nitride (AlN) is composed of aluminum nitride. In another embodiment, a target composed of aluminum may be used to form aluminum nitride reactively with the aluminum target in the presence of a nitrogen source.

In order to reduce the contact resistance and improve the efficiency of current spreading, the light emitting element 1 includes a transparent conductive layer 40 on the second semiconductor layer 22 . The material of the transparent conductive layer 40 includes a metal material or a transparent conductive oxide having a thickness of less than 500 angstroms (Å). Metal materials include chromium (Cr), titanium (Ti), tungsten (W), gold (Au), aluminum (Al), indium (In), tin (Sn), nickel (Ni), platinum (Pt) or the above materials of alloys. Transparent conductive oxides include indium tin oxide (ITO) or indium zinc oxide (IZO).

The light-emitting element 1 includes a first electrode 61 and a second electrode 62 formed on the same side of the semiconductor stack 20 . The light emitting element 1 can be of a flip chip structure or a lateral chip structure. When the light-emitting element 1 has a flip-chip structure, as shown in FIG. 1 , the light field adjustment layer 30 is disposed on the first surface 101 of the substrate 10 . When the light-emitting element 1 has a horizontal wafer structure, the light field adjustment layer 30 can be disposed on the semiconductor stack 20, for example, between the semiconductor stack 20 and the first electrode 61 and the second electrode 62 (not shown). The light field adjustment layer 30 is disposed on the main light emitting surface of the light emitting element 1 , and adjusts the light field distribution of the light emitting element 1 by adjusting the reflectivity and transmittance of the light directed toward the main light emitting surface.

When the light-emitting element 1 has a flip chip structure, as shown in FIG. 1 , in order to increase the light extraction efficiency of the light-emitting element 1 , the light-emitting element 1 may include a reflective layer 41 to reflect the active layer 23 of the semiconductor stack 20 the generated light, and the reflected light is directed toward the substrate 10 to be emitted outward. The reflective layer 41 includes a metal reflective layer or an insulating reflective structure. When the reflective layer 41 is a metal reflective layer 41 , the material thereof includes metals such as aluminum (Al), silver (Ag), rhodium (Rh) or platinum (Pt) or an alloy of the above materials. In one embodiment, in order to prevent the surface of the metal reflective layer 41 from being oxidized, thereby deteriorating the reflectivity of the metal reflective layer 41 , a barrier layer (not shown) can be formed on the metal reflective layer 41 to cover the surface of the metal reflective layer 41 . top and side surfaces. The material of the barrier layer (not shown) includes metal materials, such as titanium (Ti), tungsten (W), aluminum (Al), indium (In), tin (Sn), nickel (Ni), chromium (Cr), Metals such as platinum (Pt) or alloys of the above materials. The barrier layer may have one or more layers, such as titanium (Ti)/aluminum (Al), and/or nickel-titanium (NiTi)/titanium-tungsten (TiW). When the reflective layer 41 is the insulating reflective structure 41 , it includes alternately stacking two or more insulating materials with different refractive indices to form a distributed Bragg reflector (DBR) structure. In one embodiment of the present invention, when the reflective layer 41 is the insulating reflective structure 41 , it may include one or more through holes (not shown), and the second electrode 62 is connected to the second electrode 62 through one or a plurality of through holes of the insulating reflective structure 41 . The transparent conductive layer 40 forms electrical connections. In one embodiment of the present invention, the second electrode 62 includes a reflective metal material, which can be combined with the insulating reflective structure 41 to form an Omni-Directional Reflection.

In one embodiment of the present invention, when the light-emitting element 1 is of a horizontal wafer structure, the reflective layer 41 can be disposed on the first surface 101 of the substrate 10 .

In one embodiment of the present invention, the light-emitting element 1 includes an insulating layer 51 on the first electrode 61 and the second electrode 62 ; a first electrode pad 71 on the insulating layer 51 ; and a second electrode pad 72 on the insulating layer 51 . on layer 51. The insulating layer 51 includes a first insulating layer opening 511 to expose the first electrode 61 ; and a second insulating layer opening 512 to expose the second electrode 62 . The first electrode pad 71 contacts the first electrode 61 and is electrically connected to the first semiconductor layer 21 through the first insulating layer opening 511 . The second electrode pad 72 contacts the second electrode 62 and is electrically connected to the second semiconductor layer 22 through the second insulating layer opening 512 .

The first electrode 61 , the second electrode 62 , the first electrode pad 71 and the second electrode pad 72 include metal materials such as chromium (Cr), titanium (Ti), tungsten (W), gold (Au), and aluminum (Al) , indium (In), tin (Sn), nickel (Ni), platinum (Pt) and other metals or alloys of the above materials. The first electrode 61 , the second electrode 62 , the first electrode pad 71 and the second electrode pad 72 may be composed of a single layer or multiple layers. For example, the first electrode 61, the second electrode 62, the first electrode pad 71 and the second electrode pad 72 may include a Ti/Au layer, a Ti/Pt/Au layer, a Cr/Au layer, a Cr/Pt/Au layer, a Ni layer /Au layer, Ni/Pt/Au layer or Cr/Al/Cr/Ni/Au layer. The first electrode 61 , the second electrode 62 , the first electrode pad 71 and the second electrode pad 72 can be used as a current path for the external power supply to supply power to the first semiconductor layer 21 and the second semiconductor layer 22 . The first electrode 61 , the second electrode 62 , the first electrode pad 71 and the second electrode pad 72 include a thickness between 1 and 100 μm, preferably between 1.2 and 60 μm, and more preferably between 1.5 and 6 μm.

The materials of the protective layer 50 and the insulating layer 51 contain non-conductive materials. Non-conductive materials include organic materials, inorganic materials, or dielectric materials. Organic materials include Su8, benzocyclobutene (BCB), perfluorocyclobutane (PFCB), epoxy resin (Epoxy), acrylic resin (Acrylic Resin), cycloolefin polymer (COC), polymethyl methacrylate ester (PMMA), polyethylene terephthalate (PET), polycarbonate (PC), polyetherimide (Polyetherimide) or fluorocarbon polymer (Fluorocarbon Polymer). Inorganic materials, including Silicone or Glass. Dielectric materials include aluminum oxide (Al ₂ O ₃ ), silicon nitride (SiN), silicon oxide (SiO _x ), silicon oxynitride (SiO _x N _y ), titanium oxide (TiO _x ) or magnesium fluoride (MgF _x ) ). In one embodiment of the invention, the protective layer 50 and/or the insulating layer 51 may be a single-layer structure. In a variant of the invention, the protective layer 50 and/or the insulating layer 51 can be formed by a combination of the above-mentioned materials to form a protective layer or insulating layer with a multi-layer structure, for example, by alternately stacking two or more materials with different refractive indices to form a multilayer structure. A reflective structure containing distributed Bragg reflectors (DBR) is formed. The protective layer 50 and/or the insulating layer 51 preferably have a thickness of 0.5 μm to 4 μm, preferably a thickness of 2.5 μm to 3.5 μm, and more preferably a thickness of 2.7 μm to 3.3 μm.

In one embodiment of the protective layer 50 and/or the insulating layer 51 comprising a distributed Bragg reflector (DBR) structure, the protective layer 50 and/or the insulating layer 51 emit light having a peak wavelength λ to the semiconductor stack 20 Has a reflectivity of more than 90%. When light enters the protective layer 50 and/or the insulating layer 51 at a right angle or at various incident angles, the protective layer 50 and/or the insulating layer 51 both exhibit good reflectivity to improve luminous efficiency.

In one embodiment where the protective layer 50 and/or the insulating layer 51 includes a distributed Bragg reflector (DBR) structure, the distributed Bragg reflector (DBR) structure may include a plurality of regions, such as a first region and a second region. The first region is closest to the semiconductor stack 20 , the second region is farther from the semiconductor stack 20 , and the first region and the second region respectively have a plurality of film layers. The plurality of film layers in the first region and the second region are respectively formed by alternately stacking film layers composed of two or more materials with different refractive indices. In one embodiment, the first region and the second region are respectively formed by alternately stacking third layers and fourth layers composed of two materials. The material of the third layer has a third index of refraction (low index of refraction), such as a _SiO2 layer (n: about 1.47), and the material of the fourth layer has a fourth index of refraction (high index of refraction), such as a _TiO2 layer (n: about 2.41). In one embodiment, the third layer and the fourth layer of the first region respectively include a third optical thickness and a fourth optical thickness, and the third optical thickness and the fourth optical thickness are respectively greater than 0.25λ. The third layer and the fourth layer in the second region respectively include a third optical thickness and a fourth optical thickness, and the third optical thickness and the fourth optical thickness are respectively less than 0.25λ. In one embodiment, there are another or more regions between the first region and the second region, such as a third region and a fourth region, and the third region is closer to the first region than the fourth region. The third region and the fourth region respectively have a plurality of film layers. The plurality of film layers in the third region and the fourth region are respectively formed by alternately stacking film layers composed of two or more materials with different refractive indices. In one embodiment, similar to the first region and the second region, the third region and the fourth region are respectively formed by alternately stacking third layers and fourth layers composed of two materials. The material of the third layer has a third index of refraction (low index of refraction), such as a _SiO2 layer (n: about 1.47), and the material of the fourth layer has a fourth index of refraction (high index of refraction), such as a _TiO2 layer (n: about 2.41). In one embodiment, the third layer and the fourth layer in the third area respectively include a third optical thickness and a fourth optical thickness; the third layer and the fourth layer in the fourth area respectively include a third optical thickness and a fourth optical thickness. The third and fourth optical thicknesses of the third and fourth regions are respectively smaller than the third and fourth optical thicknesses of the first region, and greater than the third and fourth optical thicknesses of the second region, and The third optical thickness and the fourth optical thickness of the third region are greater than or equal to the third optical thickness and the fourth optical thickness of the fourth region. In one embodiment, the third optical thickness and the fourth optical thickness of the third area are respectively greater than 0.25λ, and the third optical thickness and the fourth optical thickness of the fourth area are respectively greater than 0.25λ. In one embodiment, the third optical thickness and the fourth optical thickness of the third area are respectively greater than 0.25λ, and the third optical thickness and the fourth optical thickness of the fourth area are respectively less than 0.25λ. In one embodiment, the third optical thickness and the fourth optical thickness of the third area are respectively less than 0.25λ, and the third optical thickness and the fourth optical thickness of the fourth area are respectively less than 0.25λ. In one embodiment, the third optical thickness and the fourth optical thickness of the third area are respectively equal to 0.25λ, and the third optical thickness and the fourth optical thickness of the fourth area are respectively equal to 0.25λ.

The optical thickness difference between two adjacent third material layers and fourth material layers located in each region is less than 0.05λ, more preferably less than 0.025λ. The optical thickness is the product of the physical thickness and the refractive index (n) of the material layer.

The light field adjustment layer 30 is disposed on the main light emitting surface of the light emitting element 1 , and adjusts the light field distribution of the light emitting element 1 by reflecting light in a direction perpendicular to the main light emitting surface. The light field adjustment layer 30 includes two or more materials with different refractive indices stacked alternately to form a Bragg reflector (DBR) structure, which selectively reflects light of a specific wavelength and changes the transmittance of the light according to its incident angle.

The main light emitting surface of the light emitting element 1 depends on the structure, and can emit light from one side of the substrate 10 or from one side of the first electrode 61 and the second electrode 62 . When the light-emitting element 1 has a flip chip structure, as shown in FIG. 1 , the light field adjustment layer 30 is disposed on the first surface 101 of the substrate 10 . When the light-emitting element 1 has a lateral chip structure, the light field adjustment layer 30 may be disposed between the semiconductor stack 20 and the first electrode 61 and the second electrode 62 (not shown).

Taking the light-emitting element 1 as a flip chip structure as an example, according to Snell's law, as shown in FIG. 3, since the light L travels from the semiconductor stack through the substrate 10, the light field adjustment layer The refractive index of each material encountered in the process of 30 and emitted into the air changes, so that the exit angle θj of the outgoing light after the light L passes through the light field adjustment layer 30 is greater than the incident angle θi of the light L incident on the light field adjustment layer 30 .

Specifically, as shown in FIGS. 3A and 3B , after the light L enters the light field adjustment layer 30 at an incident angle smaller than θi and exits through the light field adjustment layer 30 , there will be a first light in the first region θ1 Intensity; after the light L enters the light field adjustment layer 30 at an incident angle greater than θi and exits through the light field adjustment layer 30, there will be a second light intensity in the second region θ2, wherein the light field adjustment layer 30 is less than θi. The light transmittance of the angle is less than 50%, so the light-emitting element 1 has a bat-wing light field distribution.

As shown in FIG. 3B , the transmittance of light L is the highest near the exit angle of 60 degrees to 70 degrees, and maintains an overall high transmittance in the angle range of 30 degrees to 80 degrees.

FIG. 4 is a light field distribution diagram of a conventional light-emitting element without the light field adjustment layer 30 . Compared with Fig. 4, it can be seen from Fig. 3B that the light amount of light L between 0 degrees and 30 degrees is significantly reduced, and the light amount between 30 degrees and 90 degrees is relatively increased.

By replacing the optical structure of the lens with the light field adjustment layer 30 , the optical distribution can be adjusted at the wafer level or on the wafer, avoiding the additional use of the optical structure of the lens.

As shown in FIGS. 2A and 2B , the optical field adjustment layer 30 includes two kinds of dielectric films having different refractive indices, which are stacked multiple times in an alternating manner, for example, a first layer 30 a and a second layer 30 b. As shown in FIG. 3A and FIG. 3B , the user can adjust the light field adjustment layer 30 to reduce the transmittance of light less than the specific incident angle θi, and the transmittance of the light greater than the specific incident angle θi. increase to adjust the distribution of the bat-wing light field. For example, the light L in the light field adjustment layer 30 includes light incident at a first incident angle (not shown) and a second incident angle (not shown). When the second incident angle is greater than the specific incident angle θi, and the first incident angle is smaller than the specific incident angle θi, the transmittance of the light L at the second incident angle is greater than the transmittance at the first incident angle to realize the bat-wing light field distribution .

In this embodiment, by selecting the refractive indices, thicknesses T ₁ and T ₂ of the first layer 30 a and the second layer 30 b of the light field adjusting layer 30 and the number of stacks thereof, the penetration of the light L at each incident angle is adjusted. transmittance.

Specifically, the light field adjustment layer 30 is formed by repeatedly stacking the first layer 30 a and the second layer 30 b having different refractive indices for 2 to 50 times. The thickness of the light field adjustment layer 30, that is, the total of the _first optical thickness T1 and the _second optical thickness T2 of the plurality of first layers 30a and the plurality of second layers 30b can be designed to be 0.5 μm˜5 μm, preferably It is 1 μm to 3 μm, more preferably 1.5 μm to 2 μm.

One of the first layer 30a and the _second layer 30b of the light field adjustment layer ₃₀ is a high refractive index layer, such as _TiOx , _HfO2 , ZnO, _La2O3 , CeO2, _ZrO2 , _ZnSe , _Si3N4 , Nb ₂ O ₅ or Ta ₂ O ₅ , and the other of the first layer 30a and the second layer 30b of the light field adjustment layer 30 is a low refractive index layer, such as SiO ₂ , LaF ₃ , MgF ₂ , NaF, Na ₃ AlF _6. CaF ₂ or AlF ₃ .

In one embodiment of the invention, the first layer and/or the last layer of the light field adjustment layer 30 includes TiO _x , HfO ₂ , ZnO, La ₂ O ₃ , CeO ₂ , ZrO ₂ , ZnSe, Si ₃ N ₄ , Nb ₂ O ₅ or Ta ₂ O ₅ .

In another embodiment of the invention, the first layer and/or the last layer of the light field adjustment layer 30 includes SiO ₂ , LaF ₃ , MgF ₂ , NaF, Na ₃ AlF ₆ , CaF ₂ or AlF ₃ .

In another embodiment of the invention, the light field adjustment layer 30 further includes a first starting layer (not shown) and a second starting layer (not shown) located on the first layer 30a, the second layer 30b and the substrate. 10, wherein the first starting layer is a high refractive index layer, the second starting layer is a low refractive index layer, the optical thicknesses of the first starting layer and the second starting layer are both less than 0.25λ, and the first starting layer is It is closer to the substrate 10 or the semiconductor stack 20 than the second starting layer.

For ease of description, the first layer 30a is a high refractive index layer, such as TiO ₂ , and the second layer 30b is a low refractive index layer, such as SiO ₂ , for illustration, but it is not intended to limit the disclosure of the present invention. The light field adjustment layer 30 includes a plurality of film stacks, each region of the film stack includes a plurality of first layers 30a and a plurality of second layers 30b, the plurality of first layers 30a respectively include a first optical thickness, a plurality of second layers 30a respectively. The layers 30b each include a second optical thickness. Wherein, the plurality of first optical thicknesses are variable, and/or the plurality of second optical thicknesses are variable. The changing trend of the plurality of first optical thicknesses is to first become thinner and then thicker, or to become thicker and then thinner. The changing trend of the plurality of second optical thicknesses is to first become thinner and then thicker, or to become thicker and then thinner. Alternatively, when the optical thicknesses of one of the plurality of first layers 30a and the plurality of second layers 30b vary, the plurality of optical thicknesses of the other are substantially the same. The optical thickness difference between the two adjacent first layers and the second layers of the film stack in each region is greater than 0.025λ, preferably greater than 0.05λ, more preferably greater than 0.1λ. The optical thickness is the product of the physical thickness and the refractive index (n) of the material layer. The following will describe in detail according to different embodiments.

In one embodiment of the invention, the light field adjustment layer 30 includes a first-region film stack and a second-region film stack in the thickness direction, and the first-region film stack is closer to the substrate 10 or the semiconductor stack than the second-region film stack. Layer 20. A plurality of first layers 30a and a plurality of second layers 30b located in the first region are alternately stacked on top of each other, and a plurality of first layers 30a and a plurality of second layers 30b located in the second region are alternately stacked on top of each other. above each other. The plurality of first layers 30a of the light field adjustment layer 30 include a first optical thickness less than 0.25λ, and the plurality of second layers 30b of the light field adjustment layer 30 include a second optical thickness greater than or approximately equal to 0.25λ. As shown in FIGS. 1 , 2A and 5A to 5B, when the peak wavelength of the light L generated by the active layer 23 is λ, the plurality of first layers 30 a of the light field adjustment layer 30 respectively have a first optical The thickness T ₁ is less than 0.25λ, but greater than 0.15λ. As shown in FIG. 5A , the plurality of second layers 30b of the light field adjustment layer 30 have a second optical thickness T ₂ greater than 0.25λ but less than 0.35λ. Or as shown in FIG. 5B , the plurality of second layers 30b respectively have a second optical thickness T ₂ between 0.25λ+/-0.025λ. Under each of the above conditions, as shown in FIGS. 5A-5B, the first optical thicknesses of the plurality of first layers 30a may be thinned and then thickened, and/or the second optical thicknesses of the plurality of second layers 30b may be First thin and then thick; alternatively, the first optical thicknesses of the plurality of first layers 30a can be thinned and then thickened, and/or the second optical thicknesses of the second layers 30b can be thickened first and then thinned . In one embodiment, the first optical thicknesses of the plurality of first layers 30a can be thickened and then thinned (not shown), and/or the second optical thicknesses of the plurality of second layers 30b can be thinned first and then thinned. thick, or thicken first and then thin (not shown). In one embodiment, the first optical thicknesses of the plurality of first layers 30a may be less than 0.25λ, but greater than 0.15λ, and maintain a thickness difference within 10% (not shown), and/or the plurality of second layers 30b The second optical thickness can be greater than 0.25λ, but less than 0.35λ, and maintain a thickness difference within 10% (not shown).

The first optical thickness difference between the plurality of first layers 30a of the film stack in the first region may be smaller or greater than the first optical thickness difference between the plurality of first layers 30a of the film stack in the second region, and/or the difference in the first optical thickness between the plurality of first layers 30a of the film stack in the second region The second optical thickness difference between the plurality of second layers 30b of the first region film stack may be smaller or greater than the second optical thickness difference between the plurality of second layers 30b of the second region film stack. The first optical thickness difference is the difference between the maximum value and the minimum value of the first optical thickness. The second optical thickness difference is the difference between the maximum value and the minimum value of the second optical thickness. In this embodiment, the first optical thickness difference is between 0.025λ˜0.1λ. When the second optical thickness T ₂ is greater than 0.25λ, the second optical thickness difference is between 0.025λ˜0.1λ. When the second optical thickness T ₂ is approximately equal to 0.25λ, the second optical thickness difference is less than 0.025λ.

In another embodiment of the invention, the first layer 30a of the light field adjustment layer 30 includes a first optical thickness approximately equal to 0.25λ, and the second layer 30b of the light field adjustment layer 30 includes a second optical thickness less than or greater than 0.25 λ. As shown in FIGS. 1 , 2A and 6A to 6B, when the peak wavelength of the light L generated by the active layer 23 is λ, the first layer 30 a of the light field adjustment layer 30 has a first optical thickness T ₁ between 0.25λ+/-0.025λ. As shown in FIG. 6A, the second layer 30b has a _second optical thickness T2 less than 0.25λ, but greater than 0.15λ. As shown in FIG. 6B, the second layer 30b has a _second optical thickness T2 greater than 0.25λ, but less than 0.35λ. Under each of the above conditions, the second optical thicknesses of the plurality of second layers 30b can be thinned first and then thickened, thickened first and then thinned (not shown in the figure), or maintained within a thickness difference of 10% (not shown in the figure). shown), the first optical thicknesses of the plurality of first layers 30a are substantially the same. The second optical thickness difference between the plurality of second layers 30b in the first region may be smaller or greater than the second optical thickness difference between the plurality of second layers 30b in the second region. In this embodiment, when the second optical thickness T ₂ is less than 0.25λ, the second optical thickness difference is between 0.025λ˜0.1λ. When the second optical thickness T ₂ is greater than 0.25λ, the second optical thickness difference is between 0.025λ˜0.1λ.

In another embodiment of the invention, the first layer 30a of the light field adjustment layer 30 includes a first optical thickness greater than 0.25λ, and the second layer 30b of the light field adjustment layer 30 includes a second optical thickness less than or approximately equal to 0.25 λ. As shown in FIGS. 1 , 2A and 7A to 7B, when the peak wavelength of the light L generated by the active layer 23 is λ, the first layer 30 a of the light field adjustment layer 30 has a first optical thickness T ₁ Greater than 0.25λ, but less than 0.35λ. As shown in FIG. 7A, the second layer 30b has a _second optical thickness T2 less than 0.25λ, but greater than 0.15λ, or as shown in FIG. 7B, the _second optical thickness T2 is between 0.25λ+/-0.025 between λ. Under each of the above conditions, the first optical thicknesses of the plurality of first layers 30a can be thinned and then thickened, and/or the second optical thicknesses of the plurality of second layers 30b can be thinned and then thickened; or The first optical thicknesses of the plurality of first layers 30a may be thinned and then thickened, and/or the second optical thicknesses of the plurality of second layers 30b may be thickened and then thinned. In one embodiment, the first optical thicknesses of the plurality of first layers 30a can be thickened first and then thinned, and/or the second optical thicknesses of the plurality of second layers 30b can be thinned first and then thickened, or Thicker and thinner. In one embodiment, the first optical thicknesses of the plurality of first layers 30a may be greater than 0.25λ, but less than 0.35λ, and maintain a thickness difference within 10% (not shown), and/or the plurality of second layers 30b The second optical thickness may be less than 0.25λ, but greater than 0.15λ, and maintain a thickness difference within 10% (not shown). The first optical thickness difference between the plurality of first layers 30a of the film stack in the first region may be smaller or greater than the first optical thickness difference between the plurality of first layers 30a of the film stack in the second region, and/or the first optical thickness difference between the plurality of first layers 30a of the film stack in the second region The second optical thickness difference of the plurality of second layers 30b of the zone film stack may be smaller or greater than the second optical thickness difference between the plurality of second layers 30b of the second zone film stack. In this embodiment, the first optical thickness difference is between 0.025λ˜0.1λ. When the second optical thickness T ₂ is less than 0.25λ, the second optical thickness difference is between 0.025λ˜0.1λ. When the second optical thickness T ₂ is approximately equal to 0.25λ, the second optical thickness difference is less than 0.025λ.

In another embodiment of the invention, as shown in FIG. 1 , FIG. 2A and FIG. 8 , when the peak wavelength of the light L generated by the active layer 23 is λ, the first layer 30 a of the light field adjustment layer 30 includes A first optical thickness is less than 0.25λ, more preferably less than 0.2λ, but greater than 0.05λ. The second layer 30b of the light field adjustment layer 30 includes a second optical thickness greater than or approximately equal to 0.25λ, but less than 0.4λ. Under each of the above conditions, the ratio of the second optical thicknesses of the plurality of second layers 30b to the first optical thicknesses of the plurality of first layers 30a is greater than 2.5. In this embodiment, the first optical thickness difference is greater than 0.025λ but less than 0.1λ, and the second optical thickness difference is greater than 0.005λ but less than 0.25λ. The second optical thickness difference of the plurality of second layers 30b is greater than the first optical thickness of the plurality of first layers 30a. In this embodiment, the light field adjustment layer 30 includes a single-area film stack, and the optical thickness is the product of the physical thickness and the refractive index (n) of the material layer. The first optical thickness difference is the difference between the maximum value and the minimum value of the first optical thickness. The second optical thickness difference is the difference between the maximum value and the minimum value of the second optical thickness.

FIG. 2B is a schematic structural diagram of the light field adjustment layer 30 according to another embodiment of the present invention. As shown in FIGS. 1 and 2B, the first layer 30a of the light field adjustment layer 30 includes a first optical thickness between 0.25+/-0.025λ, and the second layer 30b includes a second optical thickness between between 0.25+/-0.025λ.

The light field adjustment layer 30 includes a first-region film stack and a second-region film stack in the thickness direction, and the first-region film stack is closer to the substrate 10 or the semiconductor stack 20 than the second-region film stack. A plurality of first layers 30a and a plurality of second layers 30b located in the first region are alternately stacked on top of each other, and a plurality of first layers 30a and a plurality of second layers 30b located in the second region are alternately stacked on top of each other. above each other. The first optical thickness difference between the plurality of first layers 30a of the film stack in the first region is substantially equal to the first optical thickness difference between the plurality of first layers 30a of the film stack in the second region, and/or the first optical thickness difference between the plurality of first layers 30a of the film stack in the second region The second optical thickness difference between the plurality of second layers 30b of the zone film stack is substantially equal to the second optical thickness difference between the plurality of second layers 30b of the second zone film stack. In this embodiment, the first optical thickness difference is less than 0.025λ, and/or the second optical thickness difference is less than 0.025λ.

In this embodiment, the light field adjustment layer 30 includes a space layer 30c located between two adjacent first layers 30a or between two adjacent second layers 30b, wherein the space layer 30c Include an optical thickness that is an even multiple of 0.25+/-0.025λ, such as 0.5+/-0.05λ or 1+/-0.1λ.

In one embodiment of the invention, the first layer 30a of the optical field adjustment layer 30 is a high refractive index layer, such as TiO _x , HfO ₂ , ZnO, La ₂ O ₃ , CeO ₂ , ZrO ₂ , ZnSe, Si ₃ N ₄ , Nb ₂ O ₅ or Ta ₂ O ₅ , and the second layer 30b of the optical field adjustment layer 30 is a low refractive index layer, such as SiO ₂ , LaF ₃ , MgF ₂ , NaF, Na ₃ AlF ₆ , CaF ₂ or AlF ₃ . If the space layer 30c is located between two adjacent first layers 30a, the space layer 30c includes SiO ₂ , LaF ₃ , MgF ₂ , NaF, Na ₃ AlF ₆ , CaF ₂ or AlF ₃ . If the space layer 30c is located between two adjacent second layers 30b, the space layer 30c includes TiO _x , HfO ₂ , ZnO, La ₂ O ₃ , CeO ₂ , ZrO ₂ , ZnSe, Si ₃ N ₄ , Nb ₂ O ₅ or Ta ₂ O ₅ .

Photons can be formed by electron beam evaporation (E-beam evaporation), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), or atomic vapor deposition. The field adjustment layer 30 can stably control the thickness of each layer of the Bragg mirror (DBR) structure.

In the field of displays, the light source is usually changed from a Lambertian light source to a bat-wing light source through secondary optical elements to achieve higher light uniformity. important. Because of the high directivity of LEDs, if used as a direct light source display, additional diffusers or secondary optical elements need to be added. The present invention achieves a better uniform light pattern design through the design of the DBR and the control of the light exit angle, so as to save the cost of the diffuser and the secondary optical element and reduce the thickness, so that the display can be made cheaper and thinner. One technology realizes various light types.

FIG. 9 is a schematic diagram of a light emitting device 100 according to an embodiment of the present invention. As shown in FIG. 9 , the light-emitting device 100 includes a circuit board 1001 and a light-emitting element 1 disposed on the circuit board 1001 . The circuit board 1001 includes a first outer electrode 1002a and a second outer electrode 1002b. The first electrode 61 and the second electrode 62 of the light-emitting element 1 can be connected to the first external electrode 1002a and the second external electrode 1002b through a first welding part 1004a and a second welding part 1004b, respectively.

The circuit board 1001 includes an insulating resin board, a ceramic board, or a metal board, such as a printed circuit board (PCB), a metal core printed circuit board (MOPCB), a metal printed circuit board (MPCB), or a flexible printed circuit board (FPCB).

In this embodiment, the first surface 101 of the substrate 10 is the main light emitting surface, and the light field adjustment layer 30 is disposed on the first surface 101 of the substrate 10 .

FIG. 10 is a schematic diagram of a backlight module 7 according to an embodiment of the present invention. The backlight module 7 includes a first frame 201; a liquid crystal display screen 202; a brightness enhancement film 300; an optical module 400; a light-emitting module assembly 500; and a second frame 700, wherein the light-emitting module assembly 500 includes Any one of the above-mentioned light-emitting elements 1 or light-emitting devices 100 is disposed in the light-emitting module assembly 500 in an edge-type or direct-type light-emitting manner. In another embodiment of the invention, the backlight module 7 further includes a wavelength conversion structure 600 on the light emitting module assembly 500 .

FIG. 11 is a schematic diagram of a display 8 according to an embodiment of the present invention. A display 8 includes an LED light-emitting panel 1000; a current source (not shown); a bracket 2000 to support the LED light-emitting panel 1000, wherein the LED light-emitting panel 1000 includes a plurality of the above-mentioned light-emitting elements 1 or light-emitting devices 100. The LED light-emitting panel 1000 includes a plurality of pixel units, and each pixel unit includes a plurality of light-emitting elements or light-emitting devices respectively emitting different colors. For example, each pixel unit includes three pixels that emit red light, green light, and blue light respectively. light-emitting element.

The embodiments exemplified in the present invention are only used to illustrate the present invention, and are not intended to limit the scope of the present invention. Any obvious modifications or changes made by anyone to the present invention do not depart from the spirit and scope of the present invention.

1: Light-emitting element

10: Substrate

20: Semiconductor stack

21: The first semiconductor layer

22: Second semiconductor layer

23: Active layer

30: Light Field Adjustment Layer

30a: first floor

30b: Second layer

30c: Spatial Layer

40: Transparent conductive layer

41: Reflective layer

50: Protective layer

51: Insulation layer

61: The first electrode

62: Second electrode

71: The first electrode pad

72: Second electrode pad

100: Lighting device

101: The first side

102: The second side

511: opening of the first insulating layer

512: opening of the second insulating layer

1001: circuit board

1002a: first external electrode

1002b: Second external electrode

1004a: First welding part

1004b: Second welding part

θi: Incident angle

θj: exit angle

θ1: first region

θ2: The second area

L: light

FIG. 1 is a side view of a light-emitting device 1 disclosed in an embodiment of the present invention.

FIG. 2 is an emission spectrum diagram of a light-emitting element 1 according to an embodiment of the present invention.

FIG. 2A is a partial enlarged view of the area A of FIG. 1 according to an embodiment of the present invention.

FIG. 2B is a partial enlarged view of the area A of FIG. 1 according to another embodiment of the present invention.

FIG. 3 is a schematic diagram of light propagation according to an embodiment of the present invention.

FIG. 3A is a schematic diagram of light propagation according to an embodiment of the present invention.

FIG. 3B is a light field distribution diagram of the light-emitting element 1 disclosed in an embodiment of the present invention.

FIG. 4 is a light field distribution diagram of a conventional light-emitting element.

FIGS. 5A to 5B are diagrams showing changes in the optical thickness of the light field adjustment layer 30 according to an embodiment of the present invention.

FIGS. 6A to 6B are diagrams of optical thickness variations of the light field adjustment layer 30 disclosed in an embodiment of the present invention.

FIGS. 7A to 7B are diagrams of optical thickness variations of the light field adjustment layer 30 disclosed in an embodiment of the present invention.

FIG. 8 is a graph showing the optical thickness variation of the light field adjustment layer 30 according to an embodiment of the present invention.

FIG. 9 is a schematic diagram of a light emitting device 100 according to an embodiment of the present invention.

FIG. 10 is a schematic diagram of a backlight module 7 according to an embodiment of the present invention.

FIG. 11 is a schematic diagram of the display 8 according to an embodiment of the present invention.

1: Light-emitting element

10: Substrate

20: Semiconductor stack

21: The first semiconductor layer

22: Second semiconductor layer

23: Active layer

30: Light Field Adjustment Layer

40: Transparent conductive layer

41: Reflective layer

50: Protective layer

51: Insulation layer

61: The first electrode

62: Second electrode

71: The first electrode pad

72: Second electrode pad

101: The first side

102: The second side

511: opening of the first insulating layer

512: opening of the second insulating layer

Claims (20)

A light-emitting element, including: a substrate; A semiconductor stack emitting a light having a peak wavelength λ on the substrate; and A light field adjustment layer is located on the substrate or the semiconductor layer, wherein the light field adjustment layer includes a plurality of first layers and a plurality of second layers, which are alternately stacked on each other, and each of the plurality of first layers includes a first layer. an optical thickness, and each of the plurality of second layers includes a second optical thickness, Wherein the first optical thickness and the second optical thickness meet any of the following: The first optical thickness is less than 0.25λ, the second optical thickness is greater than or approximately equal to 0.25λ, The first optical thickness is equal to 0.25λ, the second optical thickness is less than or greater than 0.25λ, or The first optical thickness is greater than 0.25λ, and the second optical thickness is less than or approximately equal to 0.25λ. The light-emitting device as claimed in claim 1, wherein the first optical thicknesses of the plurality of first layers are first thinned and then thickened. The light-emitting device according to claim 1, wherein the first optical thicknesses of the plurality of first layers are thickened first and then thinned. The light-emitting device according to claim 2 or claim 3, wherein the second optical thicknesses of the plurality of second layers are first thinned and then thickened. The light-emitting device according to claim 2 or claim 3, wherein the second optical thicknesses of the plurality of second layers are thickened first and then thinned. The light-emitting device according to any one of the second or third claim, wherein the light field adjustment layer comprises a first-area film stack and a second-area film stack, and is located in the first-area film stack The first optical thickness difference of the plurality of first layers is greater than the first optical thickness difference of the plurality of first layers of the second region film stack. The light-emitting device according to any one of the second or third claim, wherein the light field adjustment layer comprises a first-area film stack and a second-area film stack, and is located in the first-area film stack The first optical thickness difference of the plurality of first layers is smaller than the first optical thickness difference of the plurality of first layers of the second region film stack. The light-emitting device as claimed in claim 1, wherein a first layer and a last layer of the light field adjustment layer comprise TiO _x , HfO ₂ , ZnO, La ₂ O ₃ , CeO ₂ , ZrO ₂ , ZnSe, Si ₃ N ₄ , Nb ₂ O ₅ or Ta ₂ O ₅ . The light-emitting element of claim 1, wherein the plurality of first layers comprise TiO _x , HfO ₂ , ZnO, La ₂ O ₃ , CeO ₂ , ZrO ₂ , ZnSe, Si ₃ N ₄ , Nb ₂ O ₅ or Ta ₂ O ₅ , and the plurality of second layers comprise SiO ₂ , LaF ₃ , MgF ₂ , NaF, Na ₃ AlF ₆ , CaF ₂ or AlF ₃ . The light-emitting element according to claim 1, wherein the light-emitting element has a bat-wing light distribution. A light-emitting element, including: a substrate; A semiconductor stack emitting a light having a peak wavelength λ on the substrate; and A light field adjustment layer is located on the substrate or the semiconductor layer, wherein the light field adjustment layer includes a plurality of first layers, a plurality of second layers, and a space layer between two adjacent first layers or between two adjacent second layers, Wherein, the space layer includes an even multiple of an optical thickness of 0.25+/-0.025λ. The light _- emitting element of claim ₁₁ , wherein the plurality _of first layers comprise _TiOx , _HfO2 , ZnO, _La2O3 , CeO2, _ZrO2 , ZnSe, _Si3N4 , _{Nb2O 5} or Ta ₂ O ₅ , and the plurality of second layers comprise SiO ₂ , LaF ₃ , MgF ₂ , NaF, Na ₃ AlF ₆ , CaF ₂ or AlF ₃ . The light-emitting element as claimed in claim 12, wherein the space layer is located between two adjacent second layers, and the space layer comprises TiO _x , HfO ₂ , ZnO, La ₂ O ₃ , CeO ₂ , ZrO ₂ , ZnSe, Si ₃ N ₄ , Nb ₂ O ₅ or Ta ₂ O ₅ . The light-emitting element as claimed in claim 12, wherein the space layer is located between two adjacent first layers, and the space layer comprises SiO ₂ , LaF ₃ , MgF ₂ , NaF, Na ₃ AlF _6. CaF ₂ or AlF ₃ . The light-emitting device according to claim 11, wherein the light field adjustment layer comprises a first-area film stack and a second-area film stack, the plurality of first layers and the first-area film stack located in the first-area film stack The plurality of second layers are alternately stacked on top of each other, and the plurality of first layers and the plurality of second layers of the second region membrane stack are alternately stacked on top of each other. The light-emitting element according to claim 14, wherein the light-emitting element has a bat-wing light distribution. The light-emitting device of claim 11, wherein each of the plurality of first layers includes a first optical thickness, and each of the plurality of second layers includes a second optical thickness. The light-emitting element of claim 17, wherein the first optical thickness is between 0.25+/-0.025λ, and the second optical thickness is between 0.25+/-0.025λ. The light-emitting element according to claim 11, wherein the substrate is a transparent substrate. The light-emitting element of claim 11, wherein the optical thickness of the space layer is 0.5+/-0.05λ or 1+/-0.1λ.

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