Light emitting diode and light emitting device

Abstract

The invention relates to the technical field of semiconductors, in particular to a light-emitting diode and a light-emitting device, the light-emitting diode comprises a semiconductor laminated layer, a reflecting layer and a light-transmitting layer, the semiconductor laminated layer is provided with a first surface and a second surface which are opposite to each other, and the light-transmitting layer and the reflecting layer are respectively arranged on different surface sides of the semiconductor laminated layer. The light-transmitting layer comprises first film layers and second film layers which are alternately stacked, the uppermost layer and the lowermost layer of the light-transmitting layer are the first film layers, the refractive index of the first film layers is smaller than that of the second film layers, and the total thickness of the first film layers is larger than that of the second film layers. The light-emitting angle of the light-emitting diode can be greatly reduced, the axial light intensity of the light-emitting diode is increased, and market requirements are met.

Description

Light-emitting diode and light-emitting device Technical Field

[0001] The present invention belongs to the field of semiconductor technology, and in particular relates to a light emitting diode and a light emitting device. Background Art

[0002] The light emitting diode (LED) structure has advantages such as low power consumption, environmental protection, long service life and fast response rate. It has been widely used in related fields such as displays, automotive lighting, and general lighting backlights.

[0003] Due to their design and manufacturing process, existing conventional LEDs have a large light-emitting angle (usually 110°~160°), resulting in low axial light intensity, making them unsuitable for special fields such as wearables that require high axial light intensity.

[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a light emitting diode and a light emitting device to reduce the light emission angle of the LED and enhance the axial light intensity.

[0005] According to a first aspect of the present invention, the present invention provides a light emitting diode, comprising at least:

[0006] A semiconductor stack comprising a first semiconductor layer, a light-emitting layer, and a second semiconductor layer stacked in sequence, and having a first surface and a second surface opposite to each other;

[0007] a reflective layer, disposed on the first surface or the second surface side of the semiconductor stack;

[0008] The light-transmitting layer is arranged on the first surface or the second surface side of the semiconductor stack, and the light-transmitting layer and the reflective layer are arranged on different surface sides of the semiconductor stack, characterized in that:

[0009] The light-transmitting layer includes a first film layer and a second film layer alternately stacked, wherein the uppermost layer and the lowermost layer of the light-transmitting layer are both the first film layer, wherein the refractive index of the first film layer is smaller than the refractive index of the second film layer, and the total thickness of the first film layer is greater than the total thickness of the second film layer.

[0010] In some embodiments, the thickness of the first film layer is greater than the thickness of the second film layer immediately adjacent thereto.

[0011] In some embodiments, the first film layer closest to the semiconductor stack has the largest thickness compared to the remaining first film layers, and the first film layer farthest from the semiconductor stack has the smallest thickness compared to the remaining first film layers.

[0012] In some embodiments, the second film layer closest to the semiconductor stack has the largest thickness compared to the remaining second film layers.

[0013] In some embodiments, the thickness of the light-transmitting layer ranges from 15,000 angstroms to 21,000 angstroms.

[0014] In some embodiments, the total number of light-transmitting layers is 15-25.

[0015] In some embodiments, the thickness of the first film layer ranges from 500 angstroms to 3000 angstroms, and the thickness of the second film layer ranges from 400 angstroms to 1000 angstroms.

[0016] In some embodiments, except for the second film layer closest to the semiconductor stack, the thickness difference between the remaining second film layers is no more than 100 angstroms.

[0017] In some embodiments, except for the first film layer closest to and farthest from the semiconductor stack, the thickness difference between the remaining first film layers is no more than 200 angstroms.

[0018] In some embodiments, the material of the first film layer is silicon dioxide, and the material of the second film layer is titanium dioxide.

[0019] In some embodiments, the thickness of the reflective layer is greater than the thickness of the light-transmitting layer.

[0020] In some embodiments, the reflective layer has a thickness ranging from 30,000 angstroms to 55,000 angstroms.

[0021] In some embodiments, the reflective layer is a distributed Bragg reflector or a metal reflective layer.

[0022] In some embodiments, the light emitting diode further includes a first electrode and a second electrode, wherein the first electrode and the second electrode are both disposed on the same surface side of the semiconductor stack and are electrically connected to the first semiconductor layer and the second semiconductor layer, respectively.

[0023] In some embodiments, the light-emitting diode is a face-up light-emitting diode, the reflective layer is arranged on the first surface side of the semiconductor stack, the light-transmitting layer is arranged on the second surface side of the semiconductor stack, and a transparent conductive layer is also arranged between the light-transmitting layer and the second semiconductor layer.

[0024] In some embodiments, the light-emitting diode is a flip-chip light-emitting diode, the light-transmitting layer is arranged on the first surface side of the semiconductor stack, the reflective layer is arranged on the second surface side of the semiconductor stack, and a transparent conductive layer is also arranged between the reflective layer and the second semiconductor layer.

[0025] In some embodiments, the refractive index of the transparent conductive layer is greater than the refractive index of the first film layer and less than the refractive index of the second film layer.

[0026] In some embodiments, the light emitting diode is a vertical structure light emitting diode, the reflective layer is disposed on the first surface side of the semiconductor stack, and the light transmitting layer is disposed on the second surface side of the semiconductor stack.

[0027] In some embodiments, the light emitting diode further includes a substrate disposed on the first surface side of the semiconductor stack.

[0028] According to a second aspect of the present invention, there is provided a light emitting device comprising any light emitting diode as described above.

[0029] The light-emitting diode and light-emitting device provided in the embodiments of the present invention, by providing a light-transmitting layer including an alternately stacked first film layer and a second film layer, and matching the refractive index and thickness relationship of the first film layer and the second film layer to achieve control of the reflection waveform, can significantly reduce the light output angle of the light-emitting diode, thereby reducing the lateral light output of the light-emitting diode, thereby increasing the axial light output of the light-emitting diode, and further increasing the axial light intensity of the light-emitting diode to meet the market demand for small-angle light output.

[0030] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work. The positional relationships described in the drawings in the following description are based on the directions of the components drawn in the diagrams, unless otherwise specified.

[0032] FIG1 is a schematic structural diagram of a light emitting diode provided by a first embodiment of the present invention.

[0033] FIG2 is a schematic structural diagram of the light-transmitting layer in the first embodiment of the present invention.

[0034] FIG3 is a light distribution curve diagram of an existing light emitting diode tested using a spectrophotometer.

[0035] FIG. 4 is a light distribution curve diagram of the light emitting diode shown in FIG. 1 tested using a spectrophotometer.

[0036] FIG5 is a comparison diagram of the light intensity of the conventional light emitting diode and the light emitting diode of the first embodiment.

[0037] FIG6 is a schematic structural diagram of a light emitting diode provided by a second embodiment of the present invention.

[0038] FIG. 7 is a schematic structural diagram of a light-transmitting layer in a second embodiment of the present invention.

[0039] FIG8 is a schematic structural diagram of a light emitting diode provided in a third embodiment of the present invention.

[0040] Figure annotation:

[0041] 1-light-emitting diode; 10-semiconductor stack; 11-first semiconductor layer; 12-light-emitting layer; 13-second semiconductor layer; 101-first surface; 102-second surface; 20-reflective layer; 30-light-transmitting layer; 31-first film layer; 32-second film layer; 41-first electrode; 411-first pad electrode; 412-first contact electrode; 42-second electrode; 421-second pad electrode; 422-second contact electrode; 50-substrate; 60-transparent conductive layer; 70-passivation layer. Example

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] Referring to FIG. 1 , FIG. 1 is a schematic diagram illustrating the structure of a light-emitting diode according to a first embodiment of the present invention. The first embodiment of the present invention provides a light-emitting diode. As shown in FIG. 1 , light-emitting diode 1 is a face-up light-emitting diode, which may include a semiconductor stack 10, a reflective layer 20, and a light-transmitting layer 30.

[0044] The semiconductor stack 10 can be disposed on a substrate 50. The substrate 50 can be an insulating or conductive substrate, such as sapphire, silicon, silicon carbide, or the like. Preferably, the substrate 50 can be made of a transparent material, and the material of the substrate 50 is not particularly limited in this case. In this embodiment, the substrate 50 is a sapphire substrate. In some embodiments, the substrate 50 can be a patterned sapphire substrate.

[0045] The semiconductor stack 10 has opposing first and second surfaces 101, 102, corresponding to the lower and upper surfaces of the semiconductor stack 10 in Figure 1, respectively. From the first surface 101 to the second surface 102, the semiconductor stack 10 comprises, in order, a first semiconductor layer 11, a light-emitting layer 12, and a second semiconductor layer 13. A portion of the upper surface of the first semiconductor layer 11 is uncovered by the light-emitting layer 12 to form a mesa surface (MESA) for subsequent electrode placement. In this embodiment, the second surface 102 of the semiconductor stack 10 serves as the light-emitting surface of the light-emitting diode 1.

[0046] The first semiconductor layer 11 and the second semiconductor layer 13 can both be formed by stacking multiple layers of III-V compound semiconductor layers, such as GaN, InGaN, AlGaN, AlInGaN and other materials. They can be single-layer structures or multi-layer structures, and can be N-type doped or P-type doped to provide electrons or holes. The N-type doping impurity type can be Si, Ge, or Sn, and the P-type doping impurity type can be Mg, Zn, Ca, Sr, or Ba. This case does not exclude the doping of other elements that are equivalent to substitution. The doping conditions of the first semiconductor layer and the second semiconductor layer are different. In this embodiment, the first semiconductor layer 11 is an N-type semiconductor layer and the second semiconductor layer 13 is a P-type semiconductor layer.

[0047] The light-emitting layer 12 is a material capable of providing light radiation. It is the region where electrons and holes recombine to provide light radiation. The specific radiation wavelength range is between 390 and 950 nm, such as blue, green, red, yellow, orange, and infrared light. The light-emitting layer 12 can be a single quantum well or a periodic structure of multiple quantum wells. In this embodiment, the light-emitting layer 12 is a periodic structure of multiple quantum wells, which includes a structure of multiple well layers and multiple barrier layers alternately stacked, such as GaN / AlGaN, InGaN / GaN, InAlGaN / InAlGaN, or InGaN / AlGaN.

[0048] The reflective layer 20 is disposed on the first surface 101 side of the semiconductor stack 10. If a substrate 50 is disposed on the first surface 101 side, the reflective layer 20 is disposed below the substrate 50. The reflective layer 20 is used to reflect light emitted from the semiconductor stack 10 back to the inside of the LED 1, reducing the amount of light emitted from the side. In this embodiment, the reflective layer 20 may be a distributed Bragg reflector (DBR), which is a periodic structure composed of materials with different refractive indices. It reflects light through optical interference, reflecting light from the semiconductor stack 10 toward the reflective layer 20 back into the interior of the LED 1.

[0049] The reflective layer 20 includes a first material layer and a second material layer alternately stacked, and a first material layer and a second material layer adjacent thereto form a reflective film group. The reflective layer 20 may include one or more reflective modules. The materials of the first material layer and the second material layer are SiO2, SiON, and SiO2, respectively. x 、SiN x , Al2O3, MgF2, TiO, TiO2, Ti3O5, Ti2O3, Ta2O5, ZrO2, or any combination thereof, or a mixture thereof, wherein the first material layer and the second material layer are materials having different refractive indices. Preferably, the thickness of the reflective layer 20 ranges from 30,000 angstroms to 55,000 angstroms.

[0050] The light-transmitting layer 30 and the reflective layer 20 are disposed on different surfaces of the semiconductor stack 10. Specifically, the light-transmitting layer 30 is disposed on the second surface 102 of the semiconductor stack 10, i.e., the light-emitting surface of the LED 1. In some embodiments, the light-transmitting layer 30 may cover portions of the upper surfaces and the mesa surface (MESA) of the first and second semiconductor layers 11, 13. The light-transmitting layer 30 is used to reduce the proportion of light emitted at large lateral angles and increase the proportion of light emitted at small axial angles.

[0051] Referring to Figure 2 , the light-transmitting layer 30 includes alternating first and second layers 31, 32. In this embodiment, the first and second layers 31, 32 are alternately stacked from the first surface 101 to the second surface 102 of the semiconductor stack 10. Both the bottommost layer (starting layer) and the topmost layer (terminating layer) of the light-transmitting layer 30 are the first layers 31. The refractive index of the first layer 31 is lower than that of the second layer 32, and the total thickness of the first layer 31 is greater than that of the second layer 32. By matching the high and low refractive indices and adjusting the thickness of the layers, the light-transmitting layer 30 controls the path of incident light within the light-transmitting layer 30. This allows light with a small axial angle to exit smoothly, while light with a large lateral angle is reflected by the light-transmitting layer 30, where it is further adjusted in angle by the reflective layer 20 before re-entering the light-transmitting layer 30. This cycle maintains the light emission at a small angle, thereby increasing the axial light intensity.

[0052] In an optional embodiment, the material of the first film layer 31 can be aluminum oxide (Al2O3) or any silicon oxide compound, such as SiO2, while the material of the second film layer 32 can be any titanium oxide compound, such as TiO2, Ti3O5, etc. In this embodiment, the light-transmitting layer 30 preferably has a composite structure of alternating layers of SiO2 / TiO2, that is, the material of the first film layer 31 is silicon dioxide (SiO2), and the material of the second film layer 32 is titanium dioxide (TiO2).

[0053] In some embodiments, to better ensure that the light-transmitting layer 30 can transmit or reflect light at different incident angles, the light-transmitting layer 30 is provided with a relatively small number of layers and a relatively thin thickness. Specifically, the thickness of the light-transmitting layer 30 is significantly less than that of the reflective layer 20. Preferably, the total number of light-transmitting layers 30 is 15 to 25, with an odd number of layers. More preferably, the thickness of the light-transmitting layer 30 is in the range of 15,000 angstroms to 21,000 angstroms.

[0054] By adjusting the thickness of each film layer in the light-transmitting layer 30, light can be better extracted at small angles. Preferably, the thickness of the first film layer 31 ranges from 500 angstroms to 3000 angstroms, and the thickness of the second film layer 32 ranges from 400 angstroms to 1000 angstroms. Further preferably, the thicknesses of the film layers in the light-transmitting layer 30 are all different or partially the same. Preferably, the thickness of the first film layer 31 is greater than the thickness of the adjacent second film layer 32.

[0055] More preferably, the first film layer 31 (starting layer) closest to the semiconductor stack 10 has the largest thickness compared to the remaining first film layers 31, and the first film layer 31 (terminating layer) farthest from the semiconductor stack 10 has the smallest thickness compared to the remaining first film layers 31. The second film layer 32 closest to the semiconductor stack 10 has the largest thickness compared to the remaining second film layers 32.

[0056] Optimally, except for the first film layer 31 closest to and farthest from the semiconductor stack 10, the thickness difference between the remaining first film layers 31 is no more than 200 angstroms; except for the second film layer 32 closest to the semiconductor stack 10, the thickness difference between the remaining second film layers 32 is no more than 100 angstroms, so as to obtain a smaller light output angle and maximum axial light intensity.

[0057] Continuing with FIG. 1 , the light-emitting diode 1 further includes an electrode structure comprising a first electrode 41 and a second electrode 42. The first electrode 41, the second electrode 42, and the light-transmitting layer 30 are all located on the same surface side (the second surface 102 side) of the semiconductor stack 10. The light-transmitting layer 30 has a first opening that exposes at least a portion of the first semiconductor layer 11, and a second opening that exposes at least a portion of the second semiconductor layer 13. The first electrode 41 fills the first opening and forms an electrical connection with the first semiconductor layer 11. The second electrode 42 fills the second opening and forms an electrical connection with the second semiconductor layer 13.

[0058] Specifically, the first electrode 41 and the second electrode 42 are both metal electrodes, and the material of the first electrode 41 and the second electrode 42 is selected from one or a combination of the group consisting of Ni, Pd, Pt, Cr, Au, Ti, Ag, Al, Ge, W, SiW, Ta, AuZn, AuBe, AuGe, and AuGeNi. Typically, the first electrode 41 and the second electrode 42 are formed by depositing multiple layers of metal materials. The bottom layer of the electrode can be a metal with good adhesion, such as Cr, and the outermost layer of the electrode can be a metal with good conductivity, such as Au. The first electrode 41 can be composed of the same or similar material as the second electrode 42, or it can be composed of a different material.

[0059] In some embodiments, the light-emitting diode 1 may further include a transparent conductive layer 60, a current blocking layer, and other structures. For example, the transparent conductive layer 60 is disposed between the second semiconductor layer 13 and the light-transmitting layer 30. The refractive index of the transparent conductive layer 60 is greater than that of the first film layer 31 and less than that of the second film layer 32. Specifically, the material of the transparent conductive layer 60 may include ITO, IZO, InO, SnO, CTO, ATO, AZO, ZTO, GZO, IWO, or ZnO, but this embodiment is not limited thereto. Indium tin oxide (ITO) is a preferred choice for the transparent conductive layer 60 due to its excellent light transmittance.

[0060] According to the above embodiment, when the semiconductor stack 10 is powered, the light generated will radiate in all directions. Part of the light will be emitted to the reflective layer 20, and the other part will be emitted to the light-transmitting layer 30. The reflective layer 20 will reflect the light emitted to it back to the interior of the light-emitting diode 1 and then emit it to the light-transmitting layer 30. The light-transmitting layer 30 can filter the required light. Specifically, after the light emitted by the semiconductor stack 10 is incident on the light-transmitting layer 30, it is continuously refracted and reflected by the first film layer 31 and the second film layer 32. Ultimately, the light with a smaller light-emitting angle will be transmitted out, while the light with a larger light-emitting angle will be reflected back into the interior of the light-emitting diode 1. Then, after the angle is adjusted by the reflective layer 20, it will be emitted to the light-transmitting layer 30 again. This cycle continues until the light is adjusted to a smaller light-emitting angle and then transmitted out, ultimately obtaining a light-emitting diode 1 with a small light-emitting angle and a strong axial light output.

[0061] In this case, performance tests were conducted on the light-emitting diodes of this embodiment, as shown in Figures 3 to 5. Figure 3 is a light distribution curve obtained by spectrophotometry of a conventional light-emitting diode. Figure 4 is a light distribution curve obtained by spectrophotometry of the light-emitting diode of the first embodiment. Figure 5 is a comparison of the light intensities of the conventional light-emitting diode and the light-emitting diode of the first embodiment.

[0062] As shown in Figures 3 and 4, under the same test conditions, the light-emitting angle of the light-emitting diode 1 of this embodiment is 71.47 degrees, while the light-emitting angle of the light-emitting diode of the prior art is 132.77 degrees. The light-emitting angle of the light-emitting diode 1 of this embodiment is reduced by 61.3 degrees, a reduction of up to 46%. It can be seen that the light-emitting diode 1 of this embodiment has a significant effect on regulating the light-emitting angle. As shown in Figure 5, the axial light intensity value of the light-emitting diode 1 of this embodiment is 127.2 cd, while the axial light intensity value of the light-emitting diode of the prior art is 110.3 cd. The axial light intensity value of the light-emitting diode 1 of this embodiment is increased by 16.9 cd, an increase of 15.3%. In summary, the light-emitting angle of the light-emitting diode 1 of this embodiment is smaller, and the axial light intensity when emitting light is significantly improved.

[0063] 6 is a schematic diagram of the structure of a light emitting diode according to a second embodiment of the present invention. Compared with the light emitting diode according to the first embodiment shown in FIG1 , the light emitting diode according to this embodiment is different mainly in that the light emitting diode 1 according to this embodiment is a flip-chip light emitting diode.

[0064] The semiconductor stack 10 of the flip-chip light-emitting diode has opposing first and second surfaces 101, 102, corresponding to the lower and upper surfaces of the semiconductor stack 10 in Figure 6, respectively. From the first surface 101 to the second surface 102, the semiconductor stack 10 comprises, in order, a first semiconductor layer 11, a light-emitting layer 12, and a second semiconductor layer 13. A portion of the upper surface of the first semiconductor layer 11 is uncovered by the light-emitting layer 12 to form a mesa surface (MESA) for mounting electrodes. In this embodiment, the first semiconductor layer 11 is an N-type semiconductor layer, and the second semiconductor layer 13 is a P-type semiconductor layer.

[0065] In this embodiment, the light-emitting surface of the flip-chip LED 1 is the first surface. The light-transmitting layer 30 is disposed on the first surface 101 side of the semiconductor stack 10, and the reflective layer 20 is disposed on the second surface 102 side of the semiconductor stack 10. If a substrate 50 is disposed on the first surface 101 side, the light-transmitting layer 30 is disposed beneath the substrate 50. The substrate 50 is preferably a sapphire substrate.

[0066] Referring to FIG. 7 , the light-transmitting layer 30 includes alternating first and second film layers 31 and 32. In this embodiment, the first and second film layers 31 and 32 are alternately stacked from the second surface 102 toward the first surface 101, that is, from the upper surface to the lower surface of the semiconductor stack 10. The topmost layer (starting layer) and the bottommost layer (terminating layer) of the light-transmitting layer 30 are both the first film layers 31. The refractive index of the first film layer 31 is lower than that of the second film layer 32, and the total thickness of the first film layer 31 is greater than the total thickness of the second film layer 32.

[0067] It should be noted that, in this embodiment, the light-transmitting layer 30 and the reflective layer 20 are arranged in opposite positions to those in the first embodiment, and their specific structures are reversed, but their beneficial effects are the same as those in the first embodiment, and are not described again here.

[0068] 6 , the light emitting diode 1 further includes an electrode structure including a first electrode 41 and a second electrode 42. The first electrode 41, the second electrode 42 and the light-transmitting layer 30 are all located on the same surface side of the semiconductor stack 10 (the second surface 102 side).

[0069] The first electrode 41 includes a first pad electrode 411 and a first contact electrode 412. The first pad electrode 411 is formed on the surface of the reflective layer 20, and the first contact electrode 412 is in contact with the first semiconductor layer 11 to form an electrical connection. Specifically, the reflective layer 20 has a first opening that exposes at least a portion of the first contact electrode 412. The first pad electrode 411 fills the first opening and is in contact with the first contact electrode 412 to form an electrical connection.

[0070] The second electrode 42 includes a second pad electrode 421 and a second contact electrode 422. The second pad electrode 421 is formed on the surface of the reflective layer 20. The second contact electrode 422 is in electrical contact with the second semiconductor layer 13. The reflective layer 20 has a second opening that exposes at least a portion of the second contact electrode 422. The second pad electrode 421 fills the second opening and is in electrical contact with the second contact electrode 422. In this embodiment, the first electrode 41 is an N-electrode, and the second electrode 42 is a P-electrode.

[0071] In some embodiments, the light-emitting diode 1 may further include a transparent conductive layer 60, a current blocking layer, a passivation layer 70, and other structures. For example, the transparent conductive layer 60 is disposed between the second semiconductor layer 13 and the light-transmitting layer 30, and the passivation layer 70 is disposed between the transparent conductive layer 60 and the reflective layer 20. The specific structure of the transparent conductive layer 60 is the same as that of the first embodiment, while the passivation layer 70 must be made of a light-transmitting and insulating material. The material of the passivation layer 70 may include SiO2, SiC, SiN, Al2O3, or any combination thereof, with silicon dioxide (SiO2) being a preferred choice.

[0072] Referring to Figure 8, which is a schematic diagram of the structure of a light emitting diode according to a third embodiment of the present invention, the light emitting diode of this embodiment differs from the light emitting diodes of the first and second embodiments shown in Figures 1 or 6 in that the light emitting diode 1 of this embodiment is a vertical light emitting diode.

[0073] The semiconductor stack 10 of the vertical light-emitting diode 1 has opposing first and second surfaces 101, 102, corresponding to the lower and upper surfaces of the semiconductor stack 10 in FIG8 , respectively. From the first surface 101 to the second surface 102, the semiconductor stack 10 includes, in order, a first semiconductor layer 11, a light-emitting layer 12, and a second semiconductor layer 13. In this embodiment, the first semiconductor layer 11 is a P-type semiconductor layer, and the second semiconductor layer 13 is an N-type semiconductor layer.

[0074] Continuing with FIG8 , in this embodiment, the light-emitting surface of the vertical light-emitting diode 1 is the second surface 102. The reflective layer 20 is disposed on the first surface 101 side of the semiconductor stack 10, and the light-transmitting layer 30 is disposed on the second surface 102 side of the semiconductor stack 10. The specific structures and beneficial effects of the light-transmitting layer 30 and the reflective layer 20 are the same as those of the first embodiment and will not be further described in this embodiment.

[0075] In some embodiments, a substrate 50 is disposed on the side of the first surface 101, and a reflective layer 20 is disposed beneath the substrate 50. Specifically, the substrate 50 can be made of a transparent material, such as sapphire, silicon, or silicon carbide. In this embodiment, the substrate 50 is preferably a silicon substrate; the reflective layer 20 is a metal reflective layer, preferably a metal with high reflectivity, such as Au, Ag, Cu, or Mo. More preferably, the reflective layer 20 is a gold (Au) reflective layer, which has an extremely high light reflectivity of approximately 95% or more, effectively preventing light from escaping and being lost from the sides.

[0076] 8 , the light-emitting diode 1 further includes an electrode structure, which includes a first electrode 41 and a second electrode 42. The first electrode 41 and the second electrode 42 are located on the same surface side (the first surface 101 side) of the semiconductor stack 10, while the electrode structure and the light-transmitting layer 30 are located on different surface sides of the semiconductor stack 10.

[0077] The second electrode 42 is disposed between the semiconductor stack 10 and the substrate 50, and extends upward through the second semiconductor layer 13 to form an electrical connection therewith. The first electrode 41 is disposed above the second electrode 42 and is electrically connected to the first semiconductor layer 11. An insulating layer is disposed between the first electrode 41 and the second electrode 42 to prevent a short circuit caused by direct contact between the first electrode 41 and the second electrode 42. In this embodiment, the first electrode 41 is a P electrode, and the second electrode 42 is an N electrode.

[0078] An embodiment of the present invention may further provide a light-emitting device, which uses the light-emitting diode 1 provided by any of the above embodiments, and its specific structure and technical effects are not described in detail.

[0079] The size of the light-emitting diode 1 can be Micro LED, Mini LED, or conventional LED. The light-emitting diode 1 can be used in a backlight display or RGB display screen. Hundreds, thousands, or even tens of thousands of small-sized flip-chip light-emitting diodes can be integrated and mounted on an application substrate or a packaging substrate to form the light source portion of a backlight display device or RGB display device.

[0080] In summary, the light-emitting diode and light-emitting device provided in the embodiments of the present invention, by providing a light-transmitting layer 30 including an alternately stacked first film layer 31 and a second film layer 32, and matching the refractive index and thickness relationship of the first film layer 31 and the second film layer 32, can achieve control of the reflection waveform, which can greatly reduce the light output angle of the light-emitting diode 1, thereby reducing the lateral light output of the light-emitting diode 1, thereby increasing the axial light output of the light-emitting diode 1, and further increasing the axial light intensity of the light-emitting diode 1 to meet the market demand for small-angle light output.

[0081] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A light emitting diode, comprising at least: A semiconductor stack, comprising a first semiconductor layer, a light emitting layer and a second semiconductor layer stacked in sequence, and having a first surface and a second surface opposite to each other; A reflective layer, disposed on the first surface or the second surface side of the semiconductor stack; The light-transmitting layer is arranged on the first surface or the second surface side of the semiconductor stack, and the light-transmitting layer and the reflective layer are arranged on different surface sides of the semiconductor stack, characterized in that: The light-transmitting layer includes alternately stacked first and second film layers, wherein the uppermost and lowermost layers of the light-transmitting layer are both first film layers, wherein the refractive index of the first film layer is smaller than the refractive index of the second film layer, and the total thickness of the first film layer is greater than the total thickness of the second film layer.

2. The light emitting diode according to claim 1, characterized in that: The thickness of the first film layer is greater than the thickness of the second film layer adjacent thereto.

3. The light emitting diode according to claim 1 or 2, characterized in that: The first film layer closest to the semiconductor stack has the largest thickness compared to the other first film layers, and the first film layer farthest from the semiconductor stack has the smallest thickness compared to the other first film layers.

4. The light emitting diode according to claim 3, characterized in that: The second film layer closest to the semiconductor stack has the largest thickness compared with the other second film layers.

5. The light emitting diode according to claim 1, characterized in that: The thickness of the light-transmitting layer ranges from 15000 angstroms to 21000 angstroms.

6. The light emitting diode according to claim 1, characterized in that: The total number of light-transmitting layers is 15 to 25.

7. The light emitting diode according to claim 1, characterized in that: The thickness of the first film layer ranges from 500 angstroms to 3000 angstroms, and the thickness of the second film layer ranges from 400 angstroms to 1000 angstroms.

8. The light emitting diode according to claim 1, characterized in that: Except for the second film layer closest to the semiconductor stack, the thickness difference between the remaining second film layers is no more than 100 angstroms.

9. The light emitting diode according to claim 1, characterized in that: Except for the first film layer closest to and farthest from the semiconductor stack, the thickness difference between the remaining first film layers is no more than 200 angstroms.

10. The light emitting diode according to claim 1, characterized in that: The material of the first film layer is silicon dioxide, and the material of the second film layer is titanium dioxide.

11. The light emitting diode according to claim 1, characterized in that: The thickness of the reflective layer is greater than that of the light-transmitting layer.

12. The light emitting diode according to claim 1 or 11, characterized in that: The thickness of the reflective layer ranges from 30,000 angstroms to 55,000 angstroms.

13. The light emitting diode according to claim 1, characterized in that: The reflection layer is a distributed Bragg reflector or a metal reflection layer.

14. The light emitting diode according to claim 1, characterized in that: The light emitting diode further comprises a first electrode and a second electrode. The first electrode and the second electrode are both arranged on the same surface side of the semiconductor stack and are electrically connected to the first semiconductor layer and the second semiconductor layer respectively.

15. The light emitting diode according to claim 1, characterized in that: The light emitting diode is a front-mounted light emitting diode, wherein the reflective layer is arranged on the first surface side of the semiconductor stack, the light-transmitting layer is arranged on the second surface side of the semiconductor stack, and a transparent conductive layer is arranged between the light-transmitting layer and the second semiconductor layer.

16. The light emitting diode according to claim 1, characterized in that: The light emitting diode is a flip-chip structure light emitting diode, the light-transmitting layer is arranged on the first surface side of the semiconductor stack, the reflective layer is arranged on the second surface side of the semiconductor stack, and a transparent conductive layer is arranged between the reflective layer and the second semiconductor layer.

17. The light emitting diode according to claim 15 or 16, characterized in that: The refractive index of the transparent conductive layer is greater than the refractive index of the first film layer, and less than the refractive index of the second film layer.

18. The light emitting diode according to claim 1, characterized in that: The light emitting diode is a vertical structure light emitting diode, the reflective layer is arranged on the first surface side of the semiconductor stack, and the light-transmitting layer is arranged on the second surface side of the semiconductor stack.

19. The light emitting diode according to claim 1, characterized in that: The light emitting diode further includes a substrate, which is disposed on the first surface side of the semiconductor stack.

20. A light emitting device, characterized in that The light emitting diode comprises the light emitting diode as claimed in any one of claims 1 to 19.

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