Micro-led pixels and micro-led panels

Abstract

The present disclosure provides a micro-LED pixel and a micro-LED panel. The micro-LED pixel comprises a first light emitting mesa; a second light emitting mesa disposed above the first light emitting mesa and covering a portion of the first light emitting mesa; and a third light emitting mesa disposed above the second light emitting mesa and covering a portion of the second light emitting mesa; wherein a top surface of the first light emitting mesa is triangular in shape.

Description

Technical Field

[0001] This disclosure generally relates to microdisplay technology, and more specifically, to a microlight-emitting diode (LED) and a microLED panel. Background Technology

[0002] Typically, traditional micro-LED pixels consist of three or more micro-LED mesa arranged side-by-side to form a micro-LED panel. Three or more micro-LED mesa can emit light of different colors. However, this is not advantageous for reducing the size of micro-LED pixels.

[0003] To reduce the size of micro-LED pixels, a micro-LED pixel can include several vertically formed micro-LED layers with the same asymmetry axis. The micro-LED layers define the light-emitting area, and the electrodes of the micro-LED layers are formed on an outer panel outside the light-emitting area of ​​the micro-LED pixel. However, the outer panel increases the size of the micro-LED pixel.

[0004] Therefore, it is necessary to further improve the micro-LED pixel structure in order to reduce the size of the micro-LED pixels and increase the light-emitting area of ​​the micro-LED pixels. Summary of the Invention

[0005] Embodiments of this disclosure provide a micro LED pixel. The micro LED pixel includes: a first light-emitting platform; a second light-emitting platform disposed above the first light-emitting platform and covering a portion of the first light-emitting platform; and a third light-emitting platform disposed above the second light-emitting platform and covering a portion of the second light-emitting platform; wherein the top surface of the first light-emitting platform is triangular in shape.

[0006] Embodiments of this disclosure provide a micro LED panel. The micro LED panel includes two or more of the micro LED pixels. Attached Figure Description

[0007] The following detailed description and accompanying drawings illustrate embodiments and aspects of this disclosure. The various features shown in the figures are not drawn to scale.

[0008] Figure 1 A top view structural diagram of a micro LED pixel according to some embodiments of the present disclosure is shown.

[0009] Figure 2 The micro LED pixel edge according to some embodiments of the present disclosure is shown. Figure 1 The structural diagram of the cross-sectional view along section line A-A' shown.

[0010] Figure 3 The micro LED pixel edge according to some embodiments of the present disclosure is shown. Figure 1 The structural diagram of the cross-sectional view along section line B-B' shown.

[0011] Figure 4 A top view structural diagram of an exemplary micro-LED panel according to some embodiments of the present disclosure is shown. Detailed Implementation

[0012] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings, wherein, unless otherwise stated, the same reference numerals in the different drawings denote the same or similar elements. The embodiments described below are not representative of all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with aspects related to this disclosure. Specific aspects of this disclosure are described below in more detail. In the event of any conflict with terms and / or definitions incorporated by reference, the terms and definitions provided herein shall prevail.

[0013] In order to reduce the size of micro LED pixels and increase their light-emitting area, embodiments of this disclosure provide an improved micro LED pixel.

[0014] Figure 1 A top view structural diagram of a micro LED pixel 100 according to some embodiments of the present disclosure is shown. Figure 2 The micro LED pixel edge according to some embodiments of the present disclosure is shown. Figure 1 The structural diagram of the cross-sectional view along section line A-A' shown. Figure 3 The micro LED pixel edge according to some embodiments of the present disclosure is shown. Figure 1 The structural diagram of the cross-sectional view along section line B-B' shown.

[0015] refer to Figures 1 to 3 The micro LED pixel 100 includes three or more light-emitting platforms, such as a first light-emitting platform 110, a second light-emitting platform 120, and a third light-emitting platform 130. In the vertical direction, as... Figure 2 and Figure 3 As shown, the first light-emitting platform 110, the second light-emitting platform 120, and the third light-emitting platform 130 are arranged at different positions from bottom to top. For example, the first light-emitting platform 110 is positioned lower than the second light-emitting platform 120, and the second light-emitting platform 120 is positioned lower than the third light-emitting platform 130. In some embodiments, each of the first light-emitting platform 110, the second light-emitting platform 120, and the third light-emitting platform 130 has a columnar structure. That is, the shape of the top surface of the light-emitting platform is the same as the shape of the bottom surface of the light-emitting platform. In some embodiments, the area of ​​the top surface of the light-emitting platform is smaller than the area of ​​the bottom surface of the light-emitting platform.

[0016] The micro LED pixel 100 also includes an integrated circuit (IC) backplane 190, which serves as the base of the micro LED pixel 100. Three or more light-emitting mesa are disposed above the IC backplane 190. Each light-emitting mesa is connected to a top electrode and a bottom electrode, respectively. A first bottom pad 111, a second bottom pad 121, and a third bottom pad 131 are provided on the IC backplane 190 for connecting each bottom electrode (not shown), respectively. In some embodiments, the first bottom pad 111, the second bottom pad 121, and the third bottom pad 131 are positive pads (P pads).

[0017] In some embodiments, the first light-emitting platform 110 is located at the bottommost position. The second light-emitting platform 120 covers a portion of the first light-emitting platform 110, and the third light-emitting platform 130 covers a portion of the second light-emitting platform 120. (See reference...) Figure 1 In this example, the top surface of the first light-emitting platform 110 is triangular in shape, more specifically, a triangle with rounded corners. The top surface of the second light-emitting platform 120 is elongated and is positioned along one side of the triangle of the first light-emitting platform 110. The top surface of the third light-emitting platform 130 is circular and is positioned above one end of the second light-emitting platform 120. The top surface of the first light-emitting platform 110 is lower than the bottom surface of the second light-emitting platform 120, and the top surface of the second light-emitting platform 120 is lower than the bottom surface of the third light-emitting platform 130. That is, each light-emitting platform is spaced apart from the other light-emitting platforms, i.e., they do not contact each other.

[0018] In some embodiments, the three or more light-emitting platforms include at least a red light-emitting platform emitting red light, a green light-emitting platform emitting green light, and a blue light-emitting platform emitting blue light. For example, the first light-emitting platform 110 is a red light-emitting platform, the second light-emitting platform 120 is a green light-emitting platform, and the third light-emitting platform 130 is a blue light-emitting platform. In some embodiments, the first light-emitting platform 110 is a red light-emitting platform, the second light-emitting platform 120 is a blue light-emitting platform, and the third light-emitting platform 130 is a green light-emitting platform.

[0019] In some embodiments, a bottom conductive structure is provided on the bottom surface of each light-emitting mesa to connect the light-emitting mesa to the bottom pad. (Reference) Figures 1 to 3In this example, the first bottom conductive structure 114 of the first light-emitting mesa 110 is a bonding layer disposed between the first light-emitting mesa 100 and the integrated circuit (IC) backplane 190. The first bottom conductive structure 114 can be directly connected to the first bottom pad 111. In some embodiments, a conductive film 116 is further disposed between the first bottom conductive structure 114 and the first light-emitting mesa 110. The conductive film 116 can provide ohmic conductivity on the positive side (P-side) of the first light-emitting mesa 110, and the conductive film 116 together with the top surface of the first bottom conductive structure 114 can form an ODR (omnidirectional reflector) structure with high reflectivity. In some embodiments, the conductive film 116 is a TCO (transparent conductive oxide) film, such as an ITO (indium tin oxide) film, an AZO (antimony-doped zinc oxide) film, an ATO (antimony-doped tin oxide) film, an FTO (fluorine-doped tin oxide) film, etc. In some embodiments, the second bottom conductive structure 124 of the second light-emitting platform 120 and the third bottom conductive structure 134 of the third light-emitting platform 130 are conductive layers that can extend to the outside of the light-emitting platform.

[0020] In some embodiments, a bottom connection structure is also provided to connect each bottom conductive structure to a corresponding bottom pad. (See reference) Figures 1 to 3 In this example, a second bottom connection structure 122 is disposed next to the second light-emitting mesa 120 and connected to the second bottom pad 121. A second bottom conductive structure 124 extends and connects to the second bottom connection structure 122. Therefore, the bottom of the second light-emitting mesa 120 is connected to the second bottom pad 121 via the second bottom conductive structure 124 and the second bottom connection structure 122. A third bottom connection structure 132 is disposed next to the third light-emitting mesa 130 and connected to the third bottom pad 131. A third bottom conductive structure 134 extends and connects to the third bottom connection structure 132. Therefore, the bottom of the third light-emitting mesa 130 is connected to the third bottom pad 131 via the third bottom conductive structure 134 and the third bottom connection structure 132. In some embodiments, the second bottom connection structure 122 and the third bottom connection structure 132 are through holes, which are made of metal and have a hollow structure.

[0021] There are no restrictions on the shape of each bottom connection structure. In some embodiments, the outline of the bottom connection structure and the light-emitting platform can be rectangular, which may be convenient for the arrangement of micro LED panels.

[0022] In some embodiments, a top conductive structure is provided on the top surface of the light-emitting mesa to connect the light-emitting mesa to a top pad. Reference Figure 2In this example, a first top conductive structure 115 is disposed on the top surface of the first light-emitting platform 110. In some embodiments, the first top conductive structure 115 is a first transparent conductive layer covering the entire top surface of the first light-emitting platform 110. In some embodiments, the first top conductive structure 115 of the first light-emitting platform 110 is a first point conductive structure formed on the top surface of the first light-emitting platform 110. The point conductive structure includes a plurality of conductive points (or pads) formed on the top surface of the light-emitting platform. In some embodiments, the first point conductive structure is formed on a portion of the top surface of the first light-emitting platform 110 not covered by the second light-emitting platform 120. That is, the first point conductive structure covers a portion of the top surface of the first light-emitting platform 110. Reference Figure 3 A second top conductive structure 125 is disposed on the top surface of the second light-emitting platform 120. In some embodiments, the second top conductive structure 125 is a second transparent conductive layer covering the entire top surface of the second light-emitting platform 120. In some embodiments, the second top conductive structure 125 is a second point conductive structure formed on the top surface of the second light-emitting platform 120. In some embodiments, the second point conductive structure is formed on the portion of the top surface of the second light-emitting platform 120 not covered by the third light-emitting platform 130. That is, the second point conductive structure covers a portion of the top surface of the second light-emitting platform 120.

[0023] refer to Figure 2 and Figure 3 The micro-LED pixel 100 also includes a top conductive layer 160 formed on the top surface of the micro-LED pixel 100 and covering the micro-LED pixel 100. The top conductive layer 160 is configured to connect each light-emitting mesa to a top electrode (not shown). In some embodiments, the micro-LED pixel 100 also includes top connection structures for connecting the light-emitting mesa to the top conductive layer 160. In this example, a first top connection structure 113 is disposed on a first top conductive structure 115 of the first light-emitting mesa 110 and extends upward to the top of the micro-LED pixel 100 for connection to the top conductive layer 160. A second top connection structure 123 is disposed on a second top conductive structure 125 of the second light-emitting mesa 120 and extends upward to the top of the micro-LED pixel 100 for connection to the top conductive layer 160. The top conductive layer 160 may be directly connected to a third light-emitting mesa 130. In some embodiments, the top conductive layer 160 has a recess 161 for connection to the third light-emitting mesa 130. In some embodiments, the first top connection structure 113 and the second bottom connection structure 123 are through holes, which are made of metal and have a hollow structure. In some embodiments, the top conductive layer 160 may be connected to the top electrode, for example, via an external wire.

[0024] In some embodiments, the top conductive layer 160 is transparent with a light transmittance of not less than 70%. In some embodiments, the microLED pixel 100 further includes a top pad 180 disposed on the top surface of the top conductive layer 160 and configured to provide a contact for connection to a top electrode (not shown). In some embodiments, the top pad 180 is disposed at the edge of the microLED pixel 100 and surrounds the microLED pixel 100. In some embodiments, the top pad 180 is a negative pad (N-pad). In some embodiments, a top electrode may be disposed on an integrated circuit (IC) backplane 190, and external wires for connecting the top electrode to the top pad 180 are also provided.

[0025] refer to Figures 1 to 3 Optical isolation between adjacent micro-LED pixels can be achieved through the second bottom connection structure 122 and the third bottom connection structure 132. In some embodiments, to improve optical isolation, the micro-LED pixel 100 further includes an optical isolation structure 140, which is disposed at a corner corresponding to the triangle of the first light-emitting platform 110, wherein the third light-emitting platform 130 is not located at this corner. In some embodiments, each of the gap G1 between the second bottom connection structure 122 and the third bottom connection structure 132, the gap G2 between the second bottom connection structure 122 and the optical isolation structure 140, and the gap G2 between the third bottom connection structure 132 and the optical isolation structure 140 is no greater than 1 micrometer; for example, each of G1 and G2 is equal to or less than 0.1 micrometer. Therefore, optical isolation can be further improved.

[0026] In some embodiments, the optical isolation structure 140 is configured to extend between the top conductive layer 160 and the integrated circuit (IC) backplane 190. For example, the top of the optical isolation structure 140 is equal to or higher than the top surface of the third light-emitting mesa 130, and the bottom of the optical isolation structure 140 is equal to or lower than the bottom surface of the first light-emitting mesa 110. The optical isolation structure 140 is not connected to the light-emitting mesa (including the conductive structure and conductive film), the top conductive layer 160, or the integrated circuit (IC) backplane 190.

[0027] In some embodiments, the optical isolation structure 140 is reflective. In some embodiments, the material of the optical isolation structure 140 is metal.

[0028] Since the second bottom connection structure 122 and the third bottom connection structure 132 are connected to the positive pad, the second bottom connection structure 122 and the third bottom connection structure 132 should be electrically isolated from each other. In some embodiments, the gap G1 may also provide electrical isolation between the second bottom connection structure 122 and the third bottom connection structure 132.

[0029] The micro-LED pixel 100 also includes a dielectric material filling the space within the micro-LED pixel 100, namely the space between the integrated circuit (IC) backplane 190 and the top conductive layer 160. In some embodiments, the dielectric material fills the space between the first light-emitting mesa 110, the second light-emitting mesa 120, the third light-emitting mesa 130, the second bottom connection structure 122, the third bottom connection structure 132, the integrated circuit (IC) backplane 190, the top conductive layer 160, and the optical isolation structure 140. In some embodiments, the dielectric material is selected from one or more of silicon oxide, silicon nitride, SiCN, SiNO, or Al2O3. In some embodiments, the dielectric material is transparent.

[0030] With the above structure, the micro-LED pixels provided by the embodiments of this disclosure can achieve a good balance between high transmittance and size.

[0031] Figure 4 A top view structural diagram of an example micro-LED panel 400 according to some embodiments of the present disclosure is shown. The micro-LED panel 400 includes two or more micro-LED pixels 100 arranged in an array. Figure 4 As shown in this example, a 2×2 array is illustrated, where each microLED pixel 410, 420, 430, and 440 can have a rectangular shape. Therefore, two or more microLED pixels 100 can be arranged closely together. Most light crossing between two adjacent microLED pixels 410 and 430 can be prevented by the bottom connection structure 411 of microLED pixel 410 and the bottom connection structure 431 of microLED pixel 430. An optical isolation structure 444 of microLED pixel 440 is further provided between two adjacent microLED pixels 420 and 440 to prevent light crossing.

[0032] Different types of micro-LED panels are available. For example, the resolution of display panels typically ranges from 8×8 to 3840×2160. Common display resolutions include QVGA (Quarter Graphics Array) with a resolution of 320×240 and an aspect ratio of 4:3, XGA (Extended Graphics Array) with a resolution of 1024×768 and an aspect ratio of 4:3, D (High Definition) with a resolution of 1280×720 and an aspect ratio of 16:9, FHD (Full High Definition) with a resolution of 1920×1080 and an aspect ratio of 16:9, UHD (Ultra High Definition) with a resolution of 3840×2160 and an aspect ratio of 16:9, and 4K with a resolution of 4096×2160. A wide variety of pixel sizes are also available, from submicron and below to 10 millimeters and above. The size of the entire display area can also vary greatly, from tens of micrometers or smaller to hundreds of inches or larger.

[0033] The miniature LED panel 400 can be used as a miniature LED display panel, a miniature LED image panel, etc.

[0034] Those skilled in the art should understand that micro LED panels are not limited to the above-described structure and may include more or fewer components than shown, or may combine some components or use different components.

[0035] It should be noted that relational terms such as “first” and “second” in this document are used only to distinguish one entity or operation from another, and do not require or imply any actual relationship or order between these entities or operations. Furthermore, the words “contains,” “has,” “includes,” and “includes,” as well as other similar forms, are intended to have the same meaning and are open-ended, because one or more items following any of these words are not intended to be an exhaustive list of such one or more items, or to be limited to only the listed one or more items.

[0036] As used herein, unless otherwise expressly stated, the term "or" covers all possible combinations unless impractical. For example, if it is specified that a database may include A or B, then unless otherwise expressly stated or impractical, the database may include A or B, or A and B. As a second example, if it is specified that a database may include A, B, or C, then unless otherwise expressly stated or impractical, the database may include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C.

[0037] In the foregoing description, numerous specific details have been described, which may vary depending on the implementation. Certain adjustments and modifications may be made to some of the described embodiments. Other embodiments will be apparent to those skilled in the art upon consideration of the description and practice of this disclosure herein. This specification and embodiments are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims. The sequence of steps shown in the figures is for illustrative purposes only and is not intended to limit the scope to any particular sequence of steps. Therefore, those skilled in the art will understand that these steps may be performed in a different order while implementing the same method.

[0038] Exemplary embodiments have been disclosed in the accompanying drawings and description. However, many variations and modifications can be made to these embodiments. Therefore, although specific terms are used, they are used in a general and descriptive sense only and not for limiting purposes.

Claims

1. A miniature LED pixel, characterized in that, Comprising: a first light emitting mesa; a second light emitting mesa disposed above the first light emitting mesa and covering a portion of the first light emitting mesa; and a third light emitting mesa disposed above the second light emitting mesa and covering a portion of the second light emitting mesa, wherein a top surface of the first light emitting mesa is triangular in shape, wherein a top surface of the second light emitting mesa is elongated strip-shaped, and the second light emitting mesa is disposed along one side of the triangle of the first light emitting mesa. a top surface of the third light emitting mesa is circular in shape, and the third light emitting mesa is disposed above one end of the second light emitting mesa.

2. The micro-LED pixel of claim 1, wherein, Further comprising a plurality of bottom conductive structures configured to connect each of the first, second, and third light emitting mesas to an integrated circuit (IC) backplane, respectively.

3. The micro-LED pixel of claim 1 or 2, wherein, A first bottom conductive structure of the bottom conductive structures is a bonding layer disposed between the first light emitting mesa and the integrated circuit (IC) backplane.

4. The micro-LED pixel of claim 3, wherein, A second bottom conductive structure of the bottom conductive structures is disposed at a bottom of the second light emitting mesa, and the second bottom conductive structure is connected to the integrated circuit (IC) backplane through a first bottom connection structure.

5. The micro-LED pixel of claim 4, wherein, The first bottom connection structure is a via.

6. The micro-LED pixel of claim 5, wherein, The second bottom conductive structure is a conductive layer.

7. The micro-LED pixel of claim 5, wherein, A third bottom conductive structure of the bottom conductive structures is disposed at a bottom of the third light emitting mesa, and the third bottom conductive structure is connected to the integrated circuit (IC) backplane through a second bottom connection structure.

8. The micro-LED pixel of claim 5, wherein, Further comprising:

9. The micro-LED pixel of claim 1, wherein, a top conductive layer disposed on top of the micro LED pixel; a first top conductive structure configured to connect the first light emitting mesa to the top conductive layer; and a second top conductive structure configured to connect the second light emitting mesa to the top conductive layer. The first top conductive structure is a transparent conductive layer and covers the top surface of the first light emitting mesa. The first top conductive structure is a point conductive structure.

10. The micro-LED pixel of claim 9, wherein, The point conductive structure is formed on a portion of the top surface of the first light emitting mesa that is not covered by the second light emitting mesa.

11. The micro-LED pixel of claim 9, wherein, The first top conductive structure is connected to the top conductive layer through a top connection structure.

12. The micro-LED pixel of claim 11, wherein, The second top conductive structure is a transparent conductive layer and covers the top surface of the second light emitting mesa.

13. The micro-LED pixel of claim 9, wherein, The second top conductive structure is a point conductive structure.

14. The micro-LED pixel of claim 9, wherein, The second top conductive structure is formed on a portion of a surface of the second light emitting mesa that is not covered by the third light emitting mesa.

15. The micro-LED pixel of claim 14, wherein, The second top conductive structure is connected to the top conductive layer through a top connection structure.

16. The micro-LED pixel of claim 15, wherein, The top conductive layer is directly connected to the third light emitting mesa.

17. The micro-LED pixel of claim 9, wherein, Further comprising a top pad disposed on a top surface of the top conductive layer.

18. The micro-LED pixel of claim 9, wherein, The top pad is disposed at an edge of the top conductive layer and around the micro LED pixel.

19. The micro-LED pixel of any one of claims 9-10, wherein, Further comprising a dielectric material filled between the top conductive layer and an integrated circuit (IC) backplane.

20. The micro-LED pixel of claim 19, wherein, Further comprising an optical isolation structure disposed at a corner of the micro LED pixel.

21. The micro-LED pixel of claim 9, wherein, The first light emitting mesa is a red light emitting mesa.

22. The micro-LED pixel of claim 1, wherein, ​ 23. The micro-LED pixel of claim 1, wherein, ​ 24. The micro-LED pixel of claim 23, wherein, The third light emitting mesa is a green light emitting mesa.

25. A micro-LED panel comprising: comprise two or more micro-LED pixels according to any one of claims 1 to 24.

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