Light emitting diode assembly and method of making the same

Abstract

The present application relates to a light emitting diode assembly and a manufacturing method thereof, the light emitting diode assembly comprising a first light emitting diode and a second light emitting diode with a height difference arranged adjacently on a front surface of a substrate, the height difference being such that a height of a second active layer of the second light emitting diode on the front surface of the substrate is higher than a height of a second semiconductor layer of the first light emitting diode on the front surface of the substrate, so as to avoid or reduce as much as possible the light generated by the second active layer of the second light emitting diode from being absorbed by the semiconductor layer of the first light emitting diode adjacent thereto, to improve the light emitting efficiency of the light emitting diode assembly as a whole, and without deliberately increasing the spacing between the first light emitting diode and the second light emitting diode adjacent thereto to improve the light emitting efficiency.

Description

Technical Field

[0001] This invention relates to the field of light-emitting chips, and more particularly to a light-emitting diode assembly and its manufacturing method. Background Technology

[0002] Current light-emitting diodes (LEDs) typically have an epitaxial structure consisting of sequentially stacked N-type semiconductor layers, an active layer, and a P-type semiconductor layer. In related technologies, to improve light output, multiple LEDs are arranged into an array on the same substrate. However, when arranged in an array, the semiconductor layers of each LED absorb not only the light emitted by its own active layer but also the light emitted by adjacent LEDs. Especially with the miniaturization of LEDs, the spacing between LEDs in the array becomes increasingly smaller, exacerbating the absorption of light from adjacent LEDs and resulting in poor overall light extraction efficiency.

[0003] Therefore, improving the light extraction efficiency of LED arrays is an urgent problem to be solved. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a light-emitting diode (LED) component and its manufacturing method, aiming to solve the problem of how to improve the light extraction efficiency of LED arrays in related technologies.

[0005] The present invention provides a light-emitting diode assembly, including a substrate, a first light-emitting diode disposed on the front side of the substrate, and a second light-emitting diode disposed on the front side of the substrate and adjacent to the first light-emitting diode;

[0006] The first light-emitting diode includes a first semiconductor layer, a first active layer and a second semiconductor layer stacked sequentially from the direction away from the front side of the substrate, and the second light-emitting diode includes a third semiconductor layer, a second active layer and a fourth semiconductor layer stacked sequentially from the direction away from the front side of the substrate.

[0007] The first distance between the side of the second semiconductor layer away from the front of the substrate and the front of the substrate is less than or equal to the second distance between the side of the third semiconductor layer away from the front of the substrate and the front of the substrate.

[0008] The aforementioned light-emitting diode (LED) assembly includes a first LED and a second LED disposed adjacent to each other on the front side of a substrate. The first semiconductor layer of the first LED and the third semiconductor layer of the second LED are close to the front side of the substrate, while the second semiconductor layer of the first LED and the fourth semiconductor layer of the second LED are far from the front side of the substrate. The first distance between the side of the second semiconductor layer of the first LED that is far from the front side of the substrate and the front side of the substrate is less than or equal to the second distance between the side of the third semiconductor layer of the second LED that is far from the front side of the substrate and the front side of the substrate. This results in the second active layer of the second LED being higher than the second semiconductor layer of the first LED being higher than the second semiconductor layer of the first LED being higher than the second active layer of the first LED. The position where the light intensity of the LED is strongest is at the center of the active layer. Therefore, this height difference can be used to avoid or minimize the absorption of light generated by the second active layer of the second LED by the semiconductor layer of the adjacent first LED, thereby improving the overall light extraction efficiency of the LED assembly. In particular, when the light energy (e.g., ultraviolet light) generated by the second LED is high and easily absorbed by the semiconductor material and converted into heat energy, the light extraction efficiency can be improved even better. Furthermore, it is not necessary to deliberately increase the spacing between adjacent first and second LEDs to improve the light extraction efficiency.

[0009] Based on the same inventive concept, the present invention also provides a method for manufacturing the aforementioned light-emitting diode assembly, comprising:

[0010] The first light-emitting diode is fabricated on the front side of the substrate, and the second light-emitting diode is fabricated separately.

[0011] The fabricated second light-emitting diode is transferred to the front side of the substrate and placed adjacent to the first light-emitting diode.

[0012] The LED assembly manufactured by the above-described method includes a first LED and a second LED disposed adjacent to each other on the front side of a substrate, with a height difference. This height difference causes the height of the second active layer of the second LED on the front side of the substrate to be higher than the height of the second semiconductor layer of the first LED on the front side of the substrate. This avoids or minimizes the absorption of light generated by the second active layer of the second LED by the semiconductor layer of the adjacent first LED, thereby improving the overall light extraction efficiency of the LED assembly. Furthermore, it eliminates the need to deliberately increase the spacing between adjacent first and second LEDs to improve light extraction efficiency. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a light-emitting diode array structure in related technologies;

[0014] Figure 2A schematic diagram of the distribution of the first and second light-emitting diodes provided in an embodiment of the present invention. Figure 1 ;

[0015] Figure 3 A schematic diagram of the distribution of the first and second light-emitting diodes provided in an embodiment of the present invention. Figure 2 ;

[0016] Figure 4 A schematic diagram of the distribution of the first and second light-emitting diodes provided in an embodiment of the present invention. Figure 3 ;

[0017] Figure 5 A schematic diagram of the distribution of the first and second light-emitting diodes provided in an embodiment of the present invention. Figure 4 ;

[0018] Figure 6 A schematic diagram of the distribution of the first and second light-emitting diodes provided in an embodiment of the present invention. Figure 5 ;

[0019] Figure 7 A schematic diagram of the distribution of the first and second light-emitting diodes provided in an embodiment of the present invention. Figure 6 ;

[0020] Figure 8 Schematic diagram of a light-emitting diode assembly provided for another optional embodiment of the present invention Figure 1 ;

[0021] Figure 9 Schematic diagram of a light-emitting diode assembly provided for another optional embodiment of the present invention Figure 2 ;

[0022] Figure 10 Schematic diagram of a light-emitting diode assembly provided for another optional embodiment of the present invention Figure 3 ;

[0023] Figure 11 Schematic diagram of a light-emitting diode assembly provided for another optional embodiment of the present invention Figure 4 ;

[0024] Figure 12 Schematic diagram of a light-emitting diode assembly provided for another optional embodiment of the present invention Figure 5 ;

[0025] Figure 13 Schematic diagram of a light-emitting diode assembly provided for another optional embodiment of the present invention Figure 6 ;

[0026] Figure 14 Schematic diagram of a light-emitting diode assembly provided for another optional embodiment of the present invention Figure 7 ;

[0027] Figure 15 Schematic diagram of a light-emitting diode assembly provided for another optional embodiment of the present invention Figure 8 ;

[0028] Figure 16 Schematic diagram of a light-emitting diode assembly provided for another optional embodiment of the present invention Figure 9 ;

[0029] Figure 17 A schematic diagram of beam reflection provided for another optional embodiment of the present invention;

[0030] Figure 18 Schematic diagram of a light-emitting diode assembly provided for another optional embodiment of the present invention Figure 10 ;

[0031] Figure 19 A schematic diagram of a method for manufacturing a light-emitting diode component provided in another optional embodiment of the present invention;

[0032] Figure 20 A schematic diagram of the fabrication process of a second light-emitting diode provided in another optional embodiment of the present invention;

[0033] Figure 21 A schematic diagram of the manufacturing process of a light-emitting diode component provided in another optional embodiment of the present invention;

[0034] Explanation of reference numerals in the attached figures:

[0035] 10-Ultraviolet light-emitting diode, 101-N-type semiconductor layer, 102-Active layer, 103-P-type semiconductor layer, 1-Substrate, 2-First light-emitting diode, 21-First semiconductor layer, 22-First active layer, 23-Second semiconductor layer, 3-Second light-emitting diode, 31-Third semiconductor layer, 32-Second active layer, 33-Fourth semiconductor layer, 34-Reflective layer, 341-Adhesive layer, 342-Second reflective layer, 4-Functional layer, 41-Buffer layer, 42-N-type electrode layer, 5-Growth substrate, 6-Temporary substrate, 7-Sacrificial layer. Detailed Implementation

[0036] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0038] In related technologies, to increase light output, multiple ultraviolet light-emitting diodes (UV LEDs) are arranged into an array on the same substrate. For example, see... Figure 1 As shown, multiple ultraviolet light-emitting diodes (LEDs) 10 are arranged in an array on the same substrate. The ultraviolet LEDs 10 are LEDs made from III-nitride wide-bandgap semiconductor materials, and have broad application prospects in sterilization, polymer curing, biochemical detection, non-line-of-sight communication, and special lighting. Compared to traditional ultraviolet light sources like mercury lamps... ， Ultraviolet light-emitting diodes (UV LEDs) have many advantages, such as being mercury-free and environmentally friendly, compact and portable, low power consumption, and low voltage, and have received increasing attention and importance in recent years.

[0039] AlGaN is the core material for fabricating ultraviolet light-emitting diodes (LEDs). AlxGa1-xN is a wide-bandgap direct bandgap semiconductor. By adjusting the Al composition in the ternary compound AlGaN, the bandgap of AlGaN can be continuously varied between 3.4 and 6.2 eV, thus obtaining ultraviolet light with a wavelength range from 210 nm to 365 nm. Its structure is shown below. Figure 1 As shown, it includes an N-type semiconductor layer 101, an active layer 102, and a P-type semiconductor layer 103 stacked sequentially. However, the luminous efficiency of ultraviolet light-emitting diodes 10, especially deep ultraviolet light-emitting diodes, prepared by existing technologies is generally low, limiting the widespread application of ultraviolet light-emitting diodes. The main reason for the low luminous efficiency of ultraviolet light-emitting diodes 10 is their relatively low light extraction efficiency. The factor limiting the light extraction efficiency of ultraviolet light-emitting diodes 10 is mainly due to the strong absorption of ultraviolet light by p-type GaN (i.e., P-type semiconductor layer 103).

[0040] To improve the above problems, in related technologies, several ultraviolet light-emitting diodes 10 are combined into Figure 1 The array shown aims to increase the overall light output. However, after being arranged in an array, the P-type semiconductor layer 103 of each ultraviolet light-emitting diode 10 absorbs not only the light generated by its own active layer 102, but also the light generated by adjacent ultraviolet light-emitting diodes 10. Especially for miniaturized ultraviolet light-emitting diodes, the closer the spacing between adjacent ultraviolet light-emitting diodes, the more severe the light absorption phenomenon of the P-type semiconductor layer 103 will be, causing the luminous efficiency of the ultraviolet light-emitting diode array to decrease rather than increase. For example, see... Figure 1As shown, the light rays Z2 and Z3 generated by the active layer of the ultraviolet light-emitting diode 10 in the middle will be absorbed by the P-type semiconductor layer 103 of the ultraviolet light-emitting diodes 10 on both sides, and the light rays Z1 and Z4 emitted by the ultraviolet light-emitting diodes 10 on both sides will be absorbed by the P-type semiconductor layer 103 of the ultraviolet light-emitting diode 10 in the middle.

[0041] Based on this, the present invention aims to provide a solution that can solve the above-mentioned technical problems, the details of which will be described in subsequent embodiments.

[0042] This embodiment provides a light-emitting diode (LED) assembly, see [link / reference]. Figure 8 As shown, it includes a substrate 1, and a first light-emitting diode 2 and a second light-emitting diode 3 are arranged adjacently on the front side of the substrate 1. In this embodiment, there may be no other devices between the adjacent first light-emitting diode 2 and the second light-emitting diode 3. Of course, in some application scenarios, other devices may be arranged between the adjacent first light-emitting diode 2 and the second light-emitting diode 3 as required, which will not be described in detail here.

[0043] In this embodiment, see Figure 8 As shown, the first light-emitting diode 2 includes a first semiconductor layer 21, a first active layer 22 and a second semiconductor layer 23 stacked sequentially from the direction away from the front of the substrate 1, that is, the first semiconductor layer 21, the first active layer 22 and the second semiconductor layer 23 are stacked sequentially from bottom to top on the front of the substrate 1.

[0044] The second light-emitting diode 3 includes a third semiconductor layer 31, a second active layer 32 and a fourth semiconductor layer 33 stacked sequentially from the direction away from the front side of the substrate 1, that is, the third semiconductor layer 31, the second active layer 32 and the third semiconductor layer 31 are stacked sequentially from bottom to top on the front side of the substrate 1.

[0045] The first distance H1 between the side of the second semiconductor layer 23 away from the front of the substrate 1 (i.e., the top surface of the second semiconductor layer 23, through which light generated by the first active layer 22 passes and exits) and the front of the substrate 1 is less than or equal to the second distance H2 between the side of the third semiconductor layer 31 away from the front of the substrate 1 (i.e., the top surface of the third semiconductor layer 31, through which light generated by the second active layer 32 passes and exits) and the front of the substrate 1. This results in the second active layer 32 of the second light-emitting diode 3 being higher on the front of the substrate 1 than the second semiconductor layer 23 of the first light-emitting diode 2 being higher on the front of the substrate 1. The height difference is such that the light intensity of the second light-emitting diode 3 is strongest at the center of the second active layer 32. Therefore, this height difference can be used to avoid or minimize the absorption of light generated by the second active layer 32 of the second light-emitting diode 3 by the semiconductor layer of the adjacent first light-emitting diode 2, thereby improving the overall light extraction efficiency of the light-emitting diode assembly. In particular, when the light energy (e.g., ultraviolet light) generated by the second light-emitting diode 3 is high and easily absorbed by the semiconductor material and converted into heat energy, the light extraction efficiency can be improved even more. Moreover, it is not necessary to deliberately increase the spacing between the adjacent first light-emitting diode 2 and second light-emitting diode 3 to improve the light extraction efficiency.

[0046] For example, see Figure 8 As shown, the light L1 generated by the second active layer 32 of the second light-emitting diode 3 will no longer be absorbed by the first light-emitting diode 2 located on the left and adjacent to it. When the second light-emitting diode is also located on the right and adjacent to it, the light L2 generated by its second active layer 32 will no longer be absorbed by the first light-emitting diode 2 located on the right and adjacent to it, thereby improving the overall light output efficiency of the light-emitting diode assembly.

[0047] It should be understood that the specific number and distribution of the first light-emitting diode 2 and the second light-emitting diode 3 disposed on the substrate 1 of the light-emitting diode assembly in this embodiment can be flexibly set according to requirements. For example:

[0048] See one example Figure 2 As shown, a first light-emitting diode 2 and a second light-emitting diode 3 can be arranged adjacently on the substrate 1, thus forming a light-emitting diode array of one row and two columns or two rows and one column.

[0049] See another example Figure 3 As shown, two first light-emitting diodes 2 can be arranged adjacent to each other on the substrate 1, and a second light-emitting diode 3 can be arranged between the two first light-emitting diodes 2, thus forming a light-emitting diode array of one row and three columns or three rows and one column. Of course, the second light-emitting diode 3 located between the two first light-emitting diodes 2 may not be in the same row or column as the two first light-emitting diodes 2.

[0050] See another example. Figure 4 As shown, three first light-emitting diodes 2 and one second light-emitting diode 3 can be arranged adjacently on the substrate 1, with the three first light-emitting diodes 2 located on different three sides of the second light-emitting diode 3. Of course, the second light-emitting diode 3 located between two first light-emitting diodes 2 may not be in the same row or column as the two first light-emitting diodes 2.

[0051] See another example Figure 5 As shown, it is similar to Figure 4 The main difference shown is that a first light-emitting diode 2 is provided on all four sides of the second light-emitting diode 3.

[0052] Of course, it should be understood that in some applications, multiple sets of light-emitting diodes can be placed on the substrate, one of which is a light-emitting diode unit. Figures 2 to 5 The combination of any of the first light-emitting diodes 2 and the second light-emitting diodes 3 shown can be flexibly combined and flexibly arranged on the substrate 1.

[0053] See another example. Figure 6 As shown, multiple rows and columns of light-emitting diodes (LEDs) are arranged on the substrate 1. In each row of LEDs, a second LED 3 is placed between every two first LEDs 2. Alternatively, in each column of LEDs, a second LED 3 can be placed between every two first LEDs 2, depending on requirements. The second LEDs 3 can also be randomly or irregularly arranged in the multi-column LED array, as described in [reference needed]. Figure 7 As shown.

[0054] As can be seen from the above examples, the number of first light-emitting diodes 2 and second light-emitting diodes 3 on the substrate 1 of the light-emitting diode assembly in this embodiment, and their specific layout (which can be arrayed or non-arrayed), can be flexibly set according to requirements. As long as there is at least one first light-emitting diode 2 and one second light-emitting diode 3 arranged adjacently, the solution provided in this embodiment is applicable, and will not be described in detail here.

[0055] In this embodiment, the type of the first semiconductor layer 21 of the first light-emitting diode 2 and the type of the third semiconductor layer 31 of the second light-emitting diode 3 can be the same, for example, both can be P-type semiconductor layers or both can be N-type semiconductor layers. In this case, the type of the second semiconductor layer 23 of the first light-emitting diode 2 and the type of the fourth semiconductor layer 33 of the second light-emitting diode 3 are the same, for example, see [reference needed]. Figure 8 As shown, the first semiconductor layer 21 and the third semiconductor layer 31 are N-type semiconductor layers, and the second semiconductor layer 23 and the fourth semiconductor layer 33 are P-type semiconductor layers.

[0056] In another example of this embodiment, the type of the first semiconductor layer 21 of the first light-emitting diode 2 and the type of the third semiconductor layer 31 of the second light-emitting diode 3 can be different. For example, the first semiconductor layer 21 may be a P-type semiconductor layer and the third semiconductor layer 31 may be an N-type semiconductor layer, or the first semiconductor layer 21 may be an N-type semiconductor layer and the third semiconductor layer 31 may be a P-type semiconductor layer. See, for example, [link to example]. Figure 9 As shown, the first semiconductor layer 21 and the fourth semiconductor layer 33 are N-type semiconductor layers, and the second semiconductor layer 23 and the third semiconductor layer 31 are P-type semiconductor layers.

[0057] Furthermore, it should be understood that in this embodiment, the colors of the light emitted by the first light-emitting diode 2 and the second light-emitting diode 3 disposed on the substrate 1 can be the same or different. The colors of the emitted light can be flexibly set, and can be red, green, blue, or ultraviolet light, etc. In one application example, the light emitted by the first light-emitting diode 2 and the second light-emitting diode 3 is ultraviolet light, and the wavelength of this ultraviolet light can be between 320nm and 400nm; or between 280nm and 320nm; or between 200nm and 280nm, that is, the first light-emitting diode 2 and the second light-emitting diode 3 are ultraviolet light-emitting diodes. In this case, the first semiconductor layer 21 and the third semiconductor layer 31 can be, but are not limited to, Al. x Ga 1-x N layers, the first active layer 22 and the second active layer 32 can be, but are not limited to, Al. y Ga 1-y N / Al z Ga 1-z The N-layer, the second semiconductor layer 23, and the fourth semiconductor layer 33 can be, but are not limited to, Al. x Ga 1-x N layers.

[0058] In this embodiment, the method of making the first distance H1 between the top surface of the first active layer 22 and the front surface of the substrate 1 less than or equal to the second distance H2 between the top surface of the third semiconductor layer 31 and the front surface of the substrate 1 can be flexibly set.

[0059] For example, see [see example]. Figure 10 As shown, the light-emitting diode assembly also includes a functional layer 4 disposed on the front side of the substrate 1 between the first light-emitting diode 2 and the second light-emitting diode 3. The specific structure of the functional layer 4 can be flexibly configured according to requirements, for example, see [reference needed]. Figure 11 As shown, it includes a buffer layer 41 arranged from bottom to top and an N-electrode layer 42 arranged on the buffer layer 41 (at this time, the first semiconductor layer 21 and the third semiconductor layer 31 are both N-type semiconductor layers). Of course, a reflective layer can also be arranged on the N-electrode layer 42 as needed, or the N-electrode layer 42 can be directly arranged as a reflective layer, etc.

[0060] In this example, the first distance H1 between the top surface of the first active layer 22 and the front surface of the substrate 1 includes the height of the functional layer 4, and the second distance H2 between the top surface of the third semiconductor layer 31 and the front surface of the substrate 1 also includes the height of the functional layer 4. In one example, the height of the functional layer 4 included in H1 and the height of the functional layer 4 included in the second distance H2 can be the same, for example, see [reference needed]. Figure 10 As shown, at this time, the third distance H3 from the top surface of the third semiconductor layer 31 to the side of the first semiconductor layer 21 near the front of the substrate 1 (i.e., the bottom surface of the first semiconductor layer 21) is less than or equal to the fourth distance H4 from the top surface of the third semiconductor layer 31 to the side of the third semiconductor layer 31 near the front of the substrate 1. See [reference needed]. Figure 14 As shown.

[0061] In another example, the height of the functional layer 4 included in H1 may not be the same as the height of the functional layer 4 included in the second distance H2. For example, the height of the functional layer 4 included in H1 may be less than the height of the functional layer 4 included in the second distance H2. See [link to relevant documentation]. Figure 12 As shown, the height H5 of the functional layer 4 included in H1 is less than the height H6 of the functional layer 4 included in H2. In this case, H3 and H4 can be the same, H3 can be less than H4, or H3 can be greater than H4, as long as it ensures... Figure 12 In this case, H1 should be less than or equal to H2. Of course, in some application scenarios, the height H5 of the functional layer 4 included by H1 can also be set to be greater than or equal to the height H6 of the functional layer 4 included by H2. In this case, H3 can also be set to be less than H4, while ensuring that H1 is less than or equal to H2.

[0062] Of course, in some examples, the front side of substrate 1 can also be configured to satisfy H1 being less than or equal to H2, for example, see Figure 13 As shown, the area on the front side of the substrate 1 where the first light-emitting diode 2 is disposed can be set lower than the area on the front side of the substrate 1 where the second light-emitting diode 3 is disposed. In this case, H3 and H4 can be the same, H3 can be less than H4, or H3 can be greater than H4, as long as it ensures... Figure 13 In this case, H1 should be less than or equal to H2. Of course, in some application scenarios, the area on the front of the substrate 1 where the first light-emitting diode 2 is located can be set higher than the area on the front of the substrate 1 where the second light-emitting diode 3 is located. In this case, H3 can also be set to be less than H4, and H1 can be less than or equal to H2.

[0063] In some application scenarios of this embodiment, see Figure 14As shown, the first semiconductor layer 21 and the third semiconductor layer 31 are N-type semiconductor layers. The light-emitting diode assembly also includes an N-electrode layer 42 disposed on the front side of the substrate 1 between the first semiconductor layer 21 and the third semiconductor layer 31. The N-electrode layer 42 is electrically connected to the first semiconductor layer 21 and the third semiconductor layer 31. This avoids the need for the first light-emitting diode 2 and the second light-emitting diode 3 to have additional N-electrode layers bonded to the substrate 1, resulting in better overall integrity and lower cost. Furthermore, in this embodiment, the second semiconductor layer 23 and the fourth semiconductor layer 33 of the first light-emitting diode 2 and the second light-emitting diode 3 can also be directly electrically connected through a P-type semiconductor layer interconnection structure.

[0064] Another alternative embodiment:

[0065] In this embodiment, to further improve the light extraction efficiency of the LED assembly, a reflective layer can be provided on the second LED 3. This reflective layer can be configured to reflect the light emitted from the first LED 2 adjacent to the second LED 3, preventing the second LED 3 from absorbing this portion, thereby improving the light extraction efficiency. In some examples, the reflective layer is also configured to reflect a portion of the light emitted by the second LED 3 itself to further improve the light extraction efficiency.

[0066] For example, see one example. Figure 15 As shown, it includes a substrate 1, and a first light-emitting diode 2 and a second light-emitting diode 3 disposed adjacently on the front side of the substrate 1. Figure 15 The second light-emitting diode 3 shown is located between two first light-emitting diodes 2. Of course, the number of first light-emitting diodes 2 adjacent to the second light-emitting diode 3 can also be 1, 3, or 4, etc. See [reference needed]. Figures 2-7 As shown, it will not be elaborated further here.

[0067] exist Figure 15 In this embodiment, at least one second light-emitting diode (LED) 3 has a reflective layer 34 on the side of its fourth semiconductor layer 33 near the first LED 2. The reflective layer 34 reflects light emitted from the first LED 2 adjacent to the second LED 3, preventing the second LED 3 from absorbing this portion, thereby improving light extraction efficiency. Furthermore, in some examples, the reflective layer 34 can also reflect a portion of the light emitted by the second LED 3 itself to further improve light extraction efficiency. See, for example... Figure 17As shown, the light beams L0 and L3 emitted by the first light-emitting diodes 2 on the left and right sides of the second light-emitting diode 3 are reflected by the reflective layer 34 on the second light-emitting diode 3 to obtain light beams L01 and L31, which are then emitted. The light beams L1 and L2 emitted by the second light-emitting diode 3 itself are reflected by the reflective layer 34 to obtain light beams L11 and L21, which are then emitted. Therefore, the light extraction efficiency of the first light-emitting diodes 2 and the second light-emitting diodes 3 can be improved, thereby improving the overall light extraction efficiency of the light-emitting diode assembly.

[0068] It should be understood that in this embodiment, a reflective layer 34 may be provided only on the side of the fourth semiconductor layer 33 of the second light-emitting diode 3 near the first light-emitting diode 2, for example, corresponding to Figure 2 In the application scenario shown, the reflective layer 34 can be provided only on the left side of the fourth semiconductor layer 33; corresponding to Figure 3 In the application scenario shown, the reflective layer 34 can be provided only on the left and right sides of the fourth semiconductor layer 33; corresponding to Figure 4 In the application scenario shown, the reflective layer 34 can be provided only on the three sides adjacent to the fourth semiconductor layer 33 and each of the three first light-emitting diodes 2; corresponding to Figure 5 As shown in the application scenario, a reflective layer 34 can be provided on each of the four sides adjacent to the fourth semiconductor layer 33 and the four first light-emitting diodes 2.

[0069] In this embodiment, the specific material and structure of the reflective layer 34 can be flexibly set. For example, in one example, the reflective layer 34 includes a first reflective layer attached to the side of the fourth semiconductor layer 33, that is, the reflective layer 34 is a single-layer structure, and the first reflective layer here can be an insulating reflective layer or a conductive reflective layer, such as a metal reflective layer.

[0070] In another example, see Figure 16 As shown, the reflective layer 34 includes an adhesive layer 341 and a second reflective layer 342. The adhesive layer 341 is attached to the side of the fourth semiconductor layer 33, and the second reflective layer 342 is disposed on the adhesive layer 341, covering at least the side of the adhesive layer 341 opposite to the side of the fourth semiconductor layer 33. The second reflective layer 342 can be an insulating reflective layer or a conductive reflective layer, such as a metal reflective layer. In this example, the adhesive layer 341 can be a light-transmitting material or an opaque material. For example, in one application scenario, the material of the adhesive layer 341 can be, but is not limited to, silicon dioxide, silicon nitride, aluminum nitride, etc.

[0071] In some examples of this embodiment, in order to avoid total internal reflection of the light from the second light-emitting diode 3 at the interface between the reflective layer and the fourth semiconductor layer 33 (e.g., the interface between the adhesive layer 341 and the fourth semiconductor layer 33), the refractive index n2 of the adhesive layer 341 can be set to be greater than the refractive index n0 of air and less than the refractive index n3 of the fourth semiconductor layer 33, thereby further improving the light extraction efficiency.

[0072] In another example of this embodiment, in order to reduce the probability of total internal reflection of the light from the second light-emitting diode 3 at the interface between the reflective layer and the fourth semiconductor layer 33 (e.g., the adhesive interface between the adhesive layer 341 and the fourth semiconductor layer 33), the fourth semiconductor layer 33 may be configured to have a rough surface on the side of the reflective layer 34.

[0073] In one example of this embodiment, see Figures 15 to 17 As shown, the cross-sectional shape of the reflective layer 34 is a right-angled triangle, and one of the right-angled sides of the right-angled triangle is attached to the side of the fourth semiconductor layer 33. The right angle of the right-angled triangle is away from the front of the substrate 1, and the right angle of the right-angled triangle is close to one corner of the front of the substrate 1 (i.e., Figure 15 The reflection angle α is greater than or equal to 5° and less than or equal to 20°. In this example, the value of the reflection angle α can be flexibly determined based on the distance between adjacent first light-emitting diodes 2 and second light-emitting diodes 3, and the height difference between the first active layer 22 of the first light-emitting diode 2 and the third semiconductor layer of the second light-emitting diode 3 on the front side of the substrate 1. The smaller the distance between adjacent first light-emitting diodes 2 and second light-emitting diodes 3, and the greater the height difference between the first active layer 22 of the first light-emitting diode 2 and the third semiconductor layer of the second light-emitting diode 3 on the front side of the substrate 1, the larger the reflection angle α will be. It should be understood that the cross-sectional shape of the reflective layer 34 is not limited to the right-angled triangle in the example above, but can also be a non-right-angled triangle or an inverted trapezoid, as long as the above reflection function can be achieved.

[0074] See Figures 16 to 17 As shown, when the cross-sectional shape of the reflective layer 34 is a right triangle, the second reflective layer 342 is disposed on the hypotenuse of the right triangle.

[0075] Since radiative recombination in LEDs is concentrated at the center of the active layer, meaning the strongest light intensity is also at the center of the active layer, the influence of light absorption between adjacent first LEDs 2 and second LEDs 3 on substrate 1 can be reduced by setting a height difference as shown in the examples above. For instance, setting the second semiconductor layer 23 of the first LED 2 to be lower than the second active layer 32 of the second LED 3. Furthermore, a reflective layer 34, including an adhesive layer 341 and a second reflective layer 342, is formed on the side of the fourth semiconductor layer 33 of the second LED 3. The adhesive layer 341 is configured to be light-transmitting, for example, allowing the transmission of deep ultraviolet or ultraviolet light. Therefore, the reflective layer 34... Figure 17 As shown, this not only reflects as much of the light radiated from the radiation center of the first active layer 22 in the adjacent first light-emitting diode 2 as possible (that is, Figure 17 In addition to L0 and L3 in the second light-emitting diode 3, it can also reflect as much of the light radiated from the radiation center of the second active layer 32 as possible (that is, ...). Figure 17 In the second light-emitting diode 3, the light radiated from the radiation center of the second active layer 32 is reflected only once on the second reflective layer 342 and will not be reflected back to the fourth semiconductor layer 33, which can further improve the light extraction efficiency.

[0076] Of course, in some examples of this embodiment, the first light-emitting diode 2 and the second light-emitting diode 3 on the substrate 1 may also be configured to have the same height, for example, see [reference needed]. Figure 18 As shown, although the second light-emitting diode 3 is provided with a reflective layer 34 in the manner described above, but not limited to the manner described above, it can also reflect the light emitted by the first light-emitting diode 2 adjacent to the second light-emitting diode 3 toward the fourth semiconductor layer 33, and can reflect as much of the light radiated from the radiation center of the second active layer 32 in the second light-emitting diode 3 as possible, thereby improving the light extraction efficiency. This approach is an equivalent alternative to the solution provided by the present invention, and will not be described in detail here.

[0077] Another alternative embodiment:

[0078] For ease of understanding, this embodiment will be described below using the fabrication process of a light-emitting diode (LED) assembly as an example. In this embodiment, the fabrication method of the LED assembly is described in [reference needed]. Figure 19 As shown, it includes, but is not limited to:

[0079] S1901: A first light-emitting diode is fabricated on the front side of the substrate, and a second light-emitting diode as shown in the above embodiments is fabricated separately.

[0080] S1902: Transfer the fabricated second light-emitting diode to the front side of the substrate and place it adjacent to the first light-emitting diode.

[0081] Of course, it should be understood that in some examples, the first light-emitting diode can be fabricated separately, and then in S1902, the fabricated first light-emitting diode and the second light-emitting diode are transferred to the front side of the substrate.

[0082] Furthermore, in some examples, a functional layer can be fabricated on the front side of the substrate before fabricating the first light-emitting diode (LED) on the substrate, depending on the requirements. For ease of understanding, the following example illustrates a fabrication example of an LED assembly, where the functional layer includes a buffer layer and an N-type electrode layer, and the first semiconductor layer of the first LED and the second semiconductor layer of the second LED are N-type semiconductor layers.

[0083] join Figure 20 The separate fabrication process of the second light-emitting diode shown includes, but is not limited to:

[0084] S2001: A second array of light-emitting diodes 3 is formed on the growth substrate 5. Specifically, an epitaxial layer array of the second light-emitting diodes 3 is formed, including a fourth semiconductor layer 33, a second active layer 32, and a first semiconductor layer 21 sequentially formed on the growth substrate 5. The growth methods of the above layers can adopt various epitaxial layer formation methods, which will not be described in detail here.

[0085] S2002: The second light-emitting diode array 3 is transferred onto the temporary substrate 6, and the fourth semiconductor layer 33 is located on the temporary substrate 6 after the transfer. Optionally, in this step, the sidewalls of the fourth semiconductor layer 33 where the reflective layer needs to be formed can be roughened by etching with an etching solution, but not limited to, to obtain a rough surface.

[0086] S2003: A sacrificial layer 7 may be formed between adjacent second light-emitting diodes 3 by means of, but not limited to, inkjet printing technology, the height of the sacrificial layer 7 being equal to the height of the fourth semiconductor layer 33.

[0087] S2004: The sacrificial layer 7 is subjected to inductively coupled plasma (ICP) etching to form the bonding layer 341, which can be formed by controlling parameters such as etching power and DC bias.

[0088] S2005: A metal reflective layer is plated on the side of the adhesive layer 341 to form a second reflective layer 342.

[0089] S2006: A metal bonding layer is formed on the fourth semiconductor layer 33 as an N-type electrode layer 42. For example, the N-type electrode layer 42 can be obtained by first injecting a sacrificial layer of the same height as the fourth semiconductor layer 33 between adjacent second light-emitting diodes 3, then depositing a metal layer, finally patterning the metal layer to expose the sacrificial layer, and finally removing the sacrificial layer.

[0090] See an example of making a light-emitting diode (LED) assembly. Figure 21 As shown, it includes, but is not limited to:

[0091] S2101: A buffer layer 41 and an N-type electrode layer 42 are formed on the front side of the substrate 1.

[0092] S2102: A light-emitting stack consisting of a first semiconductor layer 21, a first active layer 22, and a second semiconductor layer 23 is formed on the N-type electrode layer 42. The wavelength of the light emitted by the first active layer 22 can be controlled by controlling the content of the Al component. The light-emitting stack is patterned according to a predetermined reflection angle α and spacing to obtain the epitaxial layers of multiple first light-emitting diodes.

[0093] S2103: Transfer the fabricated second light-emitting diode 3 to the front side of the substrate 1 and place it adjacent to the first light-emitting diode 2.

[0094] It should be understood that, Figure 20 and Figure 21 The specific manufacturing processes described herein are merely illustrative examples for ease of understanding, and can be replaced by other processes capable of achieving the same functionality. Furthermore, the resulting LED assembly includes a first LED and a second LED disposed adjacent to each other on the front side of a substrate, with a height difference between them. This height difference ensures that the height of the second active layer of the second LED on the front side of the substrate is higher than the height of the second semiconductor layer of the first LED on the front side of the substrate. This avoids or minimizes the absorption of light generated by the second active layer of the second LED by the adjacent semiconductor layer of the first LED, improving the overall light extraction efficiency of the LED assembly without needing to intentionally increase the spacing between adjacent first and second LEDs to improve light extraction efficiency.

[0095] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A light-emitting diode assembly, characterized in that, Includes a substrate, and a first light-emitting diode and a second light-emitting diode disposed adjacently on the front side of the substrate; The first light-emitting diode includes a first semiconductor layer, a first active layer and a second semiconductor layer stacked sequentially from the direction away from the front side of the substrate, and the second light-emitting diode includes a third semiconductor layer, a second active layer and a fourth semiconductor layer stacked sequentially from the direction away from the front side of the substrate. The first distance between the side of the second semiconductor layer away from the front side of the substrate and the front side of the substrate is less than or equal to the second distance between the side of the third semiconductor layer away from the front side of the substrate and the front side of the substrate; The fourth semiconductor layer is further provided with a reflective layer on the side closest to the first light-emitting diode; The reflective layer includes an adhesive layer and a second reflective layer. The refractive index of the adhesive layer is greater than that of air and less than that of the fourth semiconductor layer. The cross-sectional shape of the reflective layer is a right-angled triangle; The right triangle is defined by the corner closest to the front of the substrate as the reflection angle. The greater the height difference between the first active layer of the first light-emitting diode and the third semiconductor layer of the second light-emitting diode on the front of the substrate, the larger the reflection angle α is set.

2. The light-emitting diode assembly as described in claim 1, characterized in that, The third distance from the side of the second semiconductor layer away from the front of the substrate to the side of the first semiconductor layer near the front of the substrate is less than or equal to the fourth distance from the side of the third semiconductor layer away from the front of the substrate to the side of the third semiconductor layer near the front of the substrate.

3. The light-emitting diode assembly as described in claim 1, characterized in that, The first semiconductor layer and the third semiconductor layer are N-type semiconductor layers. The light-emitting diode assembly also includes an N-electrode layer disposed on the front side of the substrate between the first semiconductor layer and the third semiconductor layer. The N-electrode layer is electrically connected to the first semiconductor layer and the third semiconductor layer.

4. The light-emitting diode assembly as described in claim 1, characterized in that, or, The reflective layer includes an adhesive layer and a second reflective layer. The adhesive layer is attached to the side surface, and the second reflective layer is disposed on the adhesive layer and covers at least the side of the adhesive layer opposite to the side surface.

5. The light-emitting diode assembly as described in claim 1, characterized in that, One of the right-angled sides of the right triangle is attached to the side surface, the right angle of the right triangle is away from the front surface of the substrate, and the angle of the right triangle closest to the front surface of the substrate is greater than or equal to 5° and less than or equal to 20°.

6. The light-emitting diode assembly as described in claim 4, characterized in that, The side surface is rough.

7. The light-emitting diode assembly according to any one of claims 1 to 3, characterized in that, The light emitted by the first light-emitting diode and the second light-emitting diode is ultraviolet light, and the wavelength of the ultraviolet light is between 320nm and 400nm; Or, between 280nm and 320nm; Or, it is between 200nm and 280nm.

8. A method for manufacturing a light-emitting diode assembly as described in any one of claims 1 to 7, characterized in that, include: The first light-emitting diode is fabricated on the front side of the substrate, and the second light-emitting diode is fabricated separately. The fabricated second light-emitting diode is transferred to the front side of the substrate and placed adjacent to the first light-emitting diode.

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