Miniature LED display panel, manufacturing method thereof and display device

Abstract

The invention provides a miniature LED element, a miniature LED display panel and a display device. The micro LED display panel includes: a micro LED chip including a driving layer and a micro LED array disposed on the driving layer, the driving layer configured to receive a signal for driving the micro LED array; a flexible circuit board (FCB) disposed adjacent to the micro LED chip and configured to be coupled to the micro LED chip, and a plurality of LED chips disposed on the flexible circuit board and configured to be coupled to the micro LED chip; a molding layer disposed to bond the micro LED chips and the FCB together so as to leave an open area above the micro LED array; and the transparent cover is arranged in the opening area and is used for shielding the top surface of the micro LED array.

Description

Technical Field

[0001] This disclosure generally relates to microdisplay technology, and more particularly to a micro LED display panel, a method for manufacturing a micro LED display panel, and a display device. Background Technology

[0002] Inorganic micropixel light-emitting diodes, also known as micro LEDs, micro LEDs, or μ-LEDs, are becoming increasingly important due to their use in a variety of applications, including self-emissive microdisplays, visible light communication, and optogenetics. Micro LEDs exhibit better strain relaxation, higher light extraction efficiency, and more uniform current diffusion, resulting in higher output performance than conventional LEDs. Compared to conventional LEDs, micro LEDs also demonstrate several advantages, such as improved thermal effects, faster response rates, a wider operating temperature range, higher resolution, a wider color gamut, higher contrast, lower power consumption, and operability at higher current densities.

[0003] Micro-LED display panels are manufactured by integrating an array of thousands or even millions of micro-LEDs with an integrated circuit (IC) backplane. In conventional technologies, micro-LEDs are packaged on an IC backplane, with the array of micro-LEDs forming the light-emitting area in the functional region on the front side of the IC backplane. Simultaneously, the non-functional region on the front side of the IC backplane can be used as electrodes, which can create I / O ports for voltage and signal transmission. This packaging arrangement results in larger micro-LED products, requiring more space and thus hindering their application in space-constrained products.

[0004] Therefore, it is necessary to improve the packaging of micro LEDs. Summary of the Invention

[0005] Some embodiments of this disclosure provide a micro LED display panel. The micro LED display panel includes: a micro LED chip including a driving layer and a micro LED array disposed on the driving layer, the driving layer being configured to receive signals for driving the micro LED array; a flexible circuit board (FCB) disposed adjacent to the micro LED chip and configured to be coupled to the micro LED chip; a molding layer disposed on the micro LED chip and the FCB to bond the micro LED chip and the FCB together, providing an opening area above the micro LED array; and a transparent cover disposed within the opening area to shield the top surface of the micro LED array.

[0006] Some embodiments of this disclosure also provide a method for manufacturing a micro LED display panel, comprising: coupling a flexible circuit board (FCB) to a micro LED chip having a driving layer and a micro LED array disposed on the driving layer, the driving layer being configured to receive signals for driving the micro LED array, the FCB being disposed adjacent to the micro LED chip and configured to be coupled to the micro LED chip; forming a molding layer to combine the micro LED chip and the FCB into a single structure, leaving an opening area above the micro LED array; and disposing a transparent cover in the opening area to cover the top surface of the micro LED array.

[0007] Some embodiments of this disclosure provide a display device. The display device includes any of the micro LED display panels disclosed herein. Attached Figure Description

[0008] The embodiments and aspects of this disclosure are described in the following detailed description and accompanying drawings. The features shown in the figures are not drawn to scale.

[0009] Figure 1A A front structural view of an exemplary micro-LED display panel according to some embodiments of the present disclosure is shown.

[0010] Figure 1B Some embodiments based on this disclosure are shown. Figure 1A The diagram shows the rear structure of an exemplary micro LED display panel.

[0011] Figure 2A Some embodiments based on this disclosure are shown. Figure 1A The diagram shows a cross-sectional view of an exemplary micro LED display panel along section line AA.

[0012] Figure 2B Some embodiments based on this disclosure are shown. Figure 1A The diagram shows a cross-sectional view of an exemplary micro LED display panel along section line AA.

[0013] Figure 3A Some embodiments based on this disclosure are shown. Figure 1A , 2A The diagram shows the structure of the microLED chip in the exemplary microLED display panel shown in Figure 2B.

[0014] Figure 3B A structural diagram of the microLED chips in another exemplary microLED display panel according to some embodiments of the present disclosure is shown.

[0015] Figure 3CA structural diagram of the microLED chips in another exemplary microLED display panel according to some embodiments of the present disclosure is shown.

[0016] Figure 4A A front structural view of another exemplary micro-LED display panel according to some embodiments of the present disclosure is shown.

[0017] Figure 4B Some embodiments based on this disclosure are shown. Figure 4A The diagram shows the rear structure of an exemplary micro LED display panel.

[0018] Figure 5A The front of an exemplary display device having a plurality of micro-LED display panels is shown according to some embodiments of the present disclosure.

[0019] Figure 5B Some embodiments based on this disclosure are shown. Figure 5A The back of the exemplary display device shown.

[0020] Figure 6 A structural diagram of another exemplary display device with a combiner is shown, illustrating some embodiments of the present disclosure.

[0021] Figure 7 A flowchart illustrating an exemplary method for manufacturing a micro LED display panel according to some embodiments of the present disclosure.

[0022] Figure 8 A structural diagram of another exemplary display device according to some embodiments of the present disclosure is shown.

[0023] Figure 9 A structural diagram of another exemplary display device according to some embodiments of the present disclosure is shown. Detailed Implementation

[0024] Reference will now be made specifically to exemplary embodiments. Examples of these exemplary embodiments are illustrated in the accompanying drawings. The following description refers to the drawings, wherein, unless otherwise stated, the same numbers in different figures denote the same or similar elements. The implementations set forth in the following description of the exemplary embodiments do not represent all implementations consistent with the present invention. Rather, these implementations are merely examples of apparatuses and methods consistent with aspects of the invention recounted in the appended claims. Specific aspects of this disclosure are described below in more detail. If any terminology and definitions provided herein conflict with those incorporated by reference, the terminology and definitions provided herein shall prevail.

[0025] Figure 1A and 1BA structural diagram of an exemplary micro-LED display panel 10 according to some embodiments of the present disclosure is shown. Figure 2A Some embodiments based on this disclosure are shown. Figure 1A A cross-sectional view of an exemplary micro LED display panel 10 along section line AA. Figure 2B Some embodiments based on this disclosure are shown. Figure 1A A cross-sectional view of an exemplary micro-LED display panel 10 along section line AA. Figure 1A , 1B As shown in Figures 2A and 2B, the micro-LED display panel 10 includes micro-LED chips 110, a flexible circuit board (FCB) 120 (e.g., a flexible printed circuit board), a molding layer 130, and a transparent cover 140. The manufacturing process involves creating the molding layer 130 on a portion of the micro-LED chips 110 and on the FCB 120, thereby bonding the micro-LED chips 110 and the FCB 120 together into a single compact structure. In some embodiments, the molding process can also be transfer molding, injection molding, compression molding, extrusion molding, blow molding, etc. In some embodiments, the molding material of the molding layer 130 can be epoxy molding compound (EMC), acrylic (polymethyl methacrylate), acrylonitrile butadiene styrene (ABS), polyamide (PA), polycarbonate (PC), polyethylene (PE), etc. The resulting component is extremely small and can be seamlessly integrated into a display device. For example, in the deposition process, a molding layer 130 with high-temperature properties can be applied to the micro-LED chip 110 and FCB 120. At high temperatures, the molding material exhibits a softer texture, allowing it to encapsulate the micro-LED chip 110 and FCB 120. After cooling and hardening, the molding layer 130 effectively encapsulates and bonds to the micro-LED chip 110 and FCB 120, merging them into a cohesive whole. Furthermore, a transparent cover 140 can be disposed on or above the micro-LED chip 110 to protect it.

[0026] like Figure 2AAs shown, the microLED chip 110 includes a driving layer 111 and a microLED array 112 disposed on the driving layer 111. The driving layer 111 may include driving circuitry (not shown) for driving the microLED array 112 with received signals. Specifically, the driving layer 111 may include a signal region 113 for receiving signals for driving the microLED array 112 and for transmitting the signals to the driving circuitry. The microLED array 112 is not disposed on the signal region 113 to provide space for leading out electrodes that can be coupled to electrodes within the FCB 120.

[0027] To achieve a compact structure for the micro-LED display panel 10, the FCB 120 can be positioned adjacent to the signal area 113 to shorten the overall length of the micro-LED display panel 10. The distance between the micro-LED chip 110 and the FCB 120 can range from one millimeter to several millimeters. In some embodiments, the distance between the micro-LED chip 110 and the FCB 120 can be set according to the adhesion strength of the molding material of the molding layer 130, so that the components of the micro-LED chip 110 and the FCB 120 are not damaged by the applied force. It should be understood that the micro-LED chip 110 and the FCB 120 can be positioned further apart, in which case, when the adhesion strength of the molding material is relatively low, it may be necessary to use a thicker molding material for the molding layer 130.

[0028] In some implementations, FCB 120 includes a connection region 121 for leading out electrodes. FCB 120 may be coupled to a signal region 113 of a drive layer 111 within the connection region 121 of FCB 120. It should be understood that FCB 120 may not generate signals for driving the micro-LED array 112, but it can transmit these signals and thus act as a medium for transmitting signals and power. These signals may be generated by a graphics processing unit (GPU) connected to FCB 120.

[0029] Further reference Figure 1A , 1B2A and 2B can be used to configure the molding layer 130 to be bonded to the microLED chip 110 and FCB 120 (e.g., the connection area 121 of FCB 120), and to bond the microLED chip 110 and FCB 120 (e.g., the connection area 121 of FCB 120) into a single compact structure. As described above, the molding layer 130 can be disposed on a portion of the outer surface of the microLED chip 110 and FCB 120, and to bond the microLED chip 110 and FCB 120 together. More specifically, the molding layer 130 can be formed to fill the gap 150-1 between the microLED chip 110 and FCB 120, and to form on a portion of the front surface and side surface of the driving layer 111 on which the microLED chip 110 is formed, and on the ends of the FCB 120. The integrated molding layer 130 bonds the microLED chip 110 and FCB 120 into a single compact structure. Figure 2A As shown, the molding layer 130 can be configured to leave an opening region 150-2 above the micro-LED array 112. Through the opening region 150-2, the micro-LED array 112 can emit light representing the rendered image according to the received signal. Here, the molding layer 130 can bond the micro-LED chip 110 to the FCB 120 without affecting the display of the micro-LED array 112.

[0030] In some embodiments, the opening region 150-2 is formed with a specific shape having a periphery defined by the molding layer 130. For example, the opening region 150-2 may be formed with a trapezoidal cross-section and an outwardly widening opening structure. Alternatively, the opening region 150-2 may be formed with a rectangular cross-section. In the deposition process used to form the molding layer 130, the opening region 150-2 can be blocked by the mold used to form the molding layer 130. The molding material cannot fill the space occupied by the mold. After the molding layer 130 has hardened, the mold can be removed to expose the opening region 150-2. The outwardly widening opening structure or rectangular cross-section structure of the opening region 150-2 defined by the periphery of the molding layer 130 facilitates easier demolding. It should be understood that the mold can be removed upwards without damaging the already hardened molding layer 130.

[0031] Furthermore, the outwardly widened opening structure reduces unwanted reflections generated between the inner walls of the opening region 150-2. Such internal reflections within the opening region 150-2 can blur the image rendered by the microLED array 112, potentially degrading display quality. Through the outwardly widened opening structure, most of the light from the microLED array 112 can be emitted through the opening region 150-2 and reach the observer's eye directly. In some embodiments, some light from the microLED array 112 can be emitted through the opening region 150-2 with limited reflection. Figure 1A and 2A As shown, the micro-LED array 112 is fully exposed from the opening region 150-2. That is, light emitted from the micro-LED array 112 can be seen from above the opening region 150-2 within a certain viewing angle (e.g., within an angle range of 85 degrees with the central normal axis of the micro-LED array 112).

[0032] like Figure 2A As shown, a transparent cover 140 can be disposed within the opening region 150-2 to shield the top surface of the micro-LED array 112. That is, the transparent cover 140 can be disposed on or above the top surface of the micro-LED array 112 to protect it. For example, the transparent cover 140 can be directly disposed on the entire top surface of the micro-LED array 112, or the transparent cover 140 can be spaced from the top surface of the micro-LED array 112 by a distance of 1 μm to 500 μm. In some embodiments, the transparent cover 140 may include an adhesive layer (not shown) that adheres to the driving layer 111 around the top surface of the micro-LED array 112. Although the adhesive layer can be light-transmitting, it can absorb light emitted from the micro-LED array 112 to a certain extent. By providing an adhesive layer on the driving layer 111, the transparent cover 140 can be fixed to the micro-LED chip 110 without affecting the light efficiency of the micro-LED array 112. In some embodiments, the adhesive layer can be formed of epoxy adhesive, thermosetting adhesive, moisture adhesive, etc. In some implementations, the transparent cover 140 does not contact the molding layer 130. Specifically, the side surface of the transparent cover 140 is spaced from the molding layer 130 by a distance of 1 μm to 1000 μm.

[0033] Figure 3A and 3B A structural diagram of the microLED chip 110 of an exemplary microLED display panel 10 according to some embodiments of the present disclosure is shown. To clearly illustrate the circuit structure, Figure 3A and 3B Some of the components shown may not be visible from the outside and are indicated by dashed lines. For example... Figure 3A As shown, the molding layer 130 and the transparent cover 140 are omitted to better understand the layout of the micro-LED chip 110. The micro-LED array 112 can be formed on the surface of the driving layer 111 and coupled to it. Furthermore, the driving layer 111 may include metal pads 1111 disposed in a signal region 113, which is on the same surface of the driving layer 111 on which the micro-LED array 112 is formed. Some of the metal pads 1111 can be coupled to corresponding electrodes of the micro-LED array 112 to achieve inter-electrode coupling. Due to the properties of metal, the metal pads 1111 can reflect light incident upon them (…). Figure 3A and 3B (Represented as "incident light"). Some light emitted by the micro-LED array 112 inevitably strikes the metal pads 1111, for example, through one or more reflections. Such reflected light from the metal pads 1111 ( Figure 3A The reflected light (represented as "reflected light") can blur and degrade the image rendered by the micro-LED array 112.

[0034] To prevent this situation, such as Figure 3B As shown, a light-shielding layer 1112 can also be disposed on the metal pads 1111 of the driving layer 111. The light-shielding layer 1112 can absorb light incident upon it and thus improve the quality of the image rendered by the micro-LED array 112. For example, the light-shielding layer 1112 can be a black photoresist, and its thickness can be several micrometers. In some embodiments, the light-shielding layer 1112 can also be a light-shielding film with black or dark color. In some embodiments, the light-shielding layer 1112 can be adhered to the transparent cover 140. For example, the adhesive layer 1114 of the transparent cover 140 can be adhered to the light-shielding layer 1112 and surround the top surface of the micro-LED array 112. It should be understood that the adhesive layer 1114 disposed on the light-shielding layer 1112 does not need to be transparent. Furthermore, since the side surfaces of the transparent cover 140 can be spaced apart from the molding layer 130, the light-shielding layer 1112 can be observed from directly above, as shown. Figure 1A , 2A As shown in 2B.

[0035] In some implementation schemes, such as Figure 3A As shown, at least some metal pads 1111 can be formed around the micro LED array 112. Figure 3B The light-shielding layer 1112 can also be formed around the micro-LED array 112, but not between the micro-LED array 112 and the molding layer 130. Figure 3BA gap is left between (not shown). That is, the light-shielding layer 1112 is formed to cover all metal pads 1111, and when viewed from above the opening region 150-2, any area exposed on the opening region 150-2 other than the micro-LED array 112 can be blocked by the light-shielding layer 1112. The height of the light-shielding layer 1112 can be the same as the height of the micro-LED array 112. The height of an object as used herein is the distance of the highest part of the object from a reference plane (e.g., the bottom surface of the substrate layer 160 described below). For example, the height of the light-shielding layer 1112 is the distance between the top surface of the light-shielding layer 1112 and the back surface of the substrate layer 160. In this regard, the top surface of the light-shielding layer 1112 can be aligned with the top surface of the micro-LED array 112. In some embodiments, such as Figure 2A As shown, the height of the light-shielding layer 1112 can be greater than the height of the micro-LED array 112. In some embodiments, the molding layer 130 can be positioned adjacent to but not on the light-shielding layer 1112. In some embodiments, such as Figure 2B As shown, the molding layer 130 can be configured to be adjacent to and on the light-shielding layer 1112. It should be understood that... Figure 2B The height of the light-shielding layer 1112 shown can be the same as Figure 2A The heights of the light-shielding layers 1112 shown are different.

[0036] Figure 3C A structural diagram of the microLED chips in another exemplary microLED display panel according to some embodiments of the present disclosure is shown. Figure 3C As shown, multiple electrodes 180 can be used to bring out... Figure 2A and 2B The circuit 124 shown. It should be understood that electrode 180 is connected to the micro LED array 112.

[0037] Further reference Figure 1B , 2AIn addition to 2B, the micro-LED display panel 10 also includes a substrate layer 160, which is disposed in conjunction with the molding layer 130 to bond at least a portion of the micro-LED chip 110 to the FCB 120. For example, a connection region 121 of the molding layer 130, the micro-LED chip 110, and the FCB 120 may be disposed on the front surface of the substrate layer 160. On the one hand, the substrate layer 160 can provide mechanical rigidity for surface components disposed thereon (e.g., micro-LED chip 110, FCB 120, etc.). On the other hand, the substrate layer 160 can be attached to the molding layer 130 when the molding layer 130 cools and hardens. Thus, the molding layer 130, together with the substrate layer 160, can provide a sealed or semi-sealed environment for the surface components. In some embodiments, the substrate layer 160 may be formed of a steel sheet. It should be understood that other materials may also be used to form the substrate layer 160, as long as they can provide similar functionality to the steel sheet. For example, the substrate layer 160 may also be formed of ceramic, hard resin, etc.

[0038] In some implementations, the bottom surface of the micro LED chip 110 can be aligned with the bottom surface of the FCB 120. That is, the height of the bottom surface of the micro LED chip 110 can be the same as the bottom surface of the FCB 120.

[0039] In some implementation schemes, such as Figure 2A As shown, FCB 120 may include an adhesive layer 122 adhered to the front surface of substrate 160. The bottom surface of adhesive layer 122 may be aligned with the bottom surface of microLED chip 110. That is, adhesive layer 122 and microLED chip 110 may be attached to substrate 160, which serves as a planar plate. In some embodiments, the bottom surface of adhesive layer 122 may not be aligned with the bottom surface of microLED chip 110. In some embodiments, adhesive layer 122 may be conductive, and its thickness may be from 5 μm to 50 μm. With this arrangement, FCB 120 may be electrically coupled to substrate 160, which may be a common equipotential element in a display device including microLED display panel 10. For example, FCB 120 may be grounded when substrate 160 is grounded. Although not shown, FCB 120 may include conductive lines that act as ground lines and are coupled to the ground potential of elements connected to FCB 120. In some implementations, the adhesive layer 122 may be electrically insulating, and the FCB 120 may not need to be grounded.

[0040] In some embodiments, the driving layer 111 further includes an adhesive layer 1113 adhered to the front surface of the substrate layer 160. The bottom surface of the adhesive layer 1113 may be aligned with the bottom surface of the FCB 120. Specifically, if present, the bottom surface of the adhesive layer 1113 may be aligned with the bottom surface of the adhesive layer 122. In some embodiments, the adhesive layer 1113 is insulating and electrically isolates the driving layer 111 from the substrate layer 160. Because the driving layer 111 may include several electrodes or solder joints on its bottom surface, the back surface of the driving layer 111 may need to be insulated from the external environment. For example, the adhesive layer 1113 may be formed of die attach (DA) adhesive or die attach film (DAF) adhesive. In some embodiments, the bottom surface of the adhesive layer 1113 may not be aligned with the bottom surface of the FCB 120.

[0041] In some embodiments, the thickness of adhesive layer 122 may be similar to the thickness of adhesive layer 1113. In other embodiments, the thickness of adhesive layer 122 may be less than the thickness of adhesive layer 1113.

[0042] In some embodiments, the adhesive layer 122 is disposed only on the bottom surface of the connection region 121, while the substrate layer 160 may be disposed below the connection region 121 via the adhesive layer 122. In some embodiments, such as Figure 2A As shown, the adhesive layer 122 can be further disposed below the bottom surface of the region 123 adjacent to the connection region 121, while the substrate layer 160 is further disposed below the region 123 adjacent to the connection region 121 via the adhesive layer 122. The boundary between the connection region 121 and the region 123 is... Figure 2A The line shown in the middle is dashed. Since FCB 120 is flexible and can be relatively fragile, providing a longer area of ​​FCB 120 on substrate 160 can enhance its reliability in terms of the package of the connection area 121 created by molding layer 130 and substrate 160.

[0043] In some embodiments, the molding layer 130 may also be formed on the FCB 120 extending a distance L1 from the connection region 121. It should be understood that the longer arrangement of the molding layer 130 on the FCB 120 increases the adhesion between the molding layer 130 and the FCB 120. This can enhance the reliability of the FCB 120 in terms of the package created by the molding layer 130 and the substrate layer 160. In some embodiments, the distance L1 extending from the connection region 121 may be equal to or different from the length L2 of the region 123 adjacent to the connection region 121. For example, as... Figure 2B As shown, distance L1 can be longer than length L2 (for example, distance L1 can be 0.05 mm longer than length L2).

[0044] In some embodiments, FCB 120 includes a conductive line 124 extending from connection area 121. FCB 120 can be coupled to signal area 113 via line 124. In some embodiments, such as Figure 2A As shown, the molding layer 130 can be further configured as an encapsulation trace 124. In some embodiments, such as Figure 2B As shown, line 124 may include a bundle of wires extending from different locations in signal area 113 and connection area 121.

[0045] In some implementations, the height of the molding layer 130 is greater than or equal to the height of the micro-LED array 112. The higher molding layer 130 can provide additional protection for the micro-LED array 112, while the lower molding layer 130 can provide a more compact design for the micro-LED display panel 10.

[0046] In some implementation schemes, such as Figure 1A As shown, the width W of the molding layer 130 corresponds to the width of the connection area 121. That is, ignoring manufacturing tolerances and the thin deposition of the molding layer 130 at the edge of the FCB 120, the width of the molding layer 130 can be substantially equal to the width of the connection area 121. In some embodiments, the width of the molding layer 130 can be greater than all areas of the FCB 120 except for the connection area 121. In other words, the connection area 121 is the widest area within the FCB 120 to ensure the rigidity of the two connected parts.

[0047] In some implementation schemes, such as Figure 1A , 1B As shown in Figures 2A and 2B, the micro LED display panel 10 may include a rigid circuit board 170 disposed on the FCB 120 opposite to the connection area 121 and electrically coupled to the FCB 120. The rigid circuit board 170 may include one or more connectors. In this embodiment, the rigid circuit board 170 includes connectors 1701 and 1702 on one surface and connector 1703 on the opposite surface. Connectors 1701, 1702, and 1703 may be connected in a pin-slot configuration to other processing units or other rigid circuit boards of other micro LED display panels. Here, the connectors are not specified as pin-slot configurations, as long as they can be used for communication with external device I / O.

[0048] Figure 4A This diagram shows a front structural view of another exemplary micro LED display panel 40 according to some embodiments of the present disclosure. Figure 4BA rear structural view of an exemplary micro-LED display panel 40 is shown. The micro-LED display panel 40 exhibits many similarities to the micro-LED display panel 10 described above. However, the micro-LED display panel 40 includes a rigid circuit board 460. In some embodiments, the rigid circuit board 460 may have a different shape and function than the rigid circuit board 170 of the micro-LED display panel 10. Specifically, the rigid circuit board 460 includes a memory chip 4602. In some embodiments, the rigid circuit board 460 may also include a cover disposed on or above the memory chip 4602 for protecting the memory chip 4602. The rigid circuit board 460 also includes a connector 4601 located on one surface and the memory chip 4602 located on the surface opposite the connector 4601. The connector 4601 and the memory chip 4602 are connected together for storing data in and outputting data from the memory chip 4602 via the connector 4601. For example, the memory chip 4602 can cache or store patterns to be displayed or instructions for displaying patterns for the micro-LED display panel 40, which can reduce the communication cost between the micro-LED display panel 40 and the signal source (e.g., GPU) and thus improve display efficiency.

[0049] Figure 1A , 1B The miniature LED display panel 10, shown in 2A and 2B, with connectors 1701 to 1703 on both surfaces, can be used as a hub for connection to the miniature LED display panel 40. Other aspects of the miniature LED display panel 40 can be found in [reference needed]. Figure 1A , 1B 2A and 2B are understood by referring to the description of the micro LED display panel 10, and will not be described in detail here. It should be understood that, referring to... Figure 1A , 1B The miniature LED display panels 10 of 2A and 2B may also include memory chips coupled to one or more of connectors 1701, 1702, and 1703.

[0050] Figure 5A This illustration shows a miniature LED display panel 501 (e.g., with) some embodiments according to this disclosure. Figure 1A , 1B (corresponding to miniature LED display panel 10 in 2A and 2B) and miniature LED display panels 502 and 503 (e.g., each corresponding to...) Figure 4A and 4B The front side of an exemplary display device 50 (corresponding to the miniature LED display panel 40 in the image). Figure 5B The back of an exemplary display device 50 is shown. To clearly illustrate the coupling relationship between the connectors, Figure 5A and 5BSome components shown may not be visible from the outside and are indicated by dashed lines.

[0051] like Figure 5A As shown, connectors 4601 of micro LED display panels 502 and 503 are respectively inserted into connectors 1701 and 1702 of micro LED display panel 501, forming an exemplary display device 50 with three cooperating micro LED display panels. More specifically, panels 502 and 503 can be flipped by twisting their respective FCBs so that connectors 4601 of panels 502 and 503 face connectors 1701 and 1702 of micro LED display panel 501, respectively. These micro LED display panels can be specifically driven by connectors 1703 on the back of micro LED display panel 501 via signals received from micro LED display panel 501, such as... Figure 5B As shown. Connector 1703 can be connected to an external device that generates the signal. It should be understood that the micro LED display panels 501, 502, and 503 can be used to display the red, green, and blue components of the composite image, respectively. That is, micro LED display panel 501 can render a red image, micro LED display panel 502 can render a green image, and micro LED display panel 503 can render a blue image.

[0052] Figure 6 Another exemplary display device 60 having a combiner 600 is shown according to some embodiments of the present disclosure. (See also...) Figure 6 The display device 60 (e.g., a color projector) includes Figure 5A and 5B The diagram shows micro-LED display panels 501, 502, and 503, as well as a combiner 600 (e.g., a combining prism). The combiner 600 can be used to combine (also “composite”) images rendered by the micro-LED display panels 501, 502, and 503 into a composite image. It should be understood that the display device 60 may also include other components necessary for operation, which are omitted here.

[0053] As described above, the micro LED display panel 501 can render a red image, the micro LED display panel 502 can render a green image, and the micro LED display panel 503 can render a blue image. These images can be combined into a multicolor image by the combiner 600. The red, green, and blue images can be aligned after being passed through the combiner 600 to form a multicolor image.

[0054] In some implementations, the microLED chip 110 includes an integrated circuit (IC) backplane (e.g., Figure 2A and3A The driving layer 111 is shown. The micro-LED array 112 includes a plurality of micro-LEDs (not shown). Each micro-LED can form at least a portion of a pixel unit on the micro-LED chip 110. For example, for a monochrome display, a pixel unit can be formed by a single micro-LED; and for a color display, a pixel unit can be formed by three micro-LEDs. In some embodiments, each size of the micro-LED chip 110 is no more than 1 centimeter (cm), preferably no more than 20 micrometers (μm). The resolution of the micro-LED array 112 can be 720×480, 640×480, 1920×1080, 1280×720, 2K (i.e., 2048×1080), or 4K (i.e., 3840×2160). The diameter of the micro-LEDs is in the nanometer range, for example, from 20 nm to 100 nm. In some embodiments, the spacing of the micro-LED array 112, i.e., the minimum center-to-center distance between adjacent micro-LEDs, can be in the range of 2 μm to 50 μm. In some embodiments, the number of pixels in the microLED chip 110 can range from thousands to millions or more. In some embodiments, the microLED array 112 may include blue microLEDs, green microLEDs, or red microLEDs.

[0055] In some embodiments, the IC backplane is electrically connected to each microLED of the microLED array 112 via a separate metal interconnect. In some embodiments, each microLED is individually electrically controlled via the IC backplane. In some embodiments, the IC backplane is electrically connected to the electrodes of the microLED chip 110 via a metal interconnect. In some embodiments, a dielectric layer may be formed in the gaps between the microLEDs. In some embodiments, the dielectric layer may also be formed in the gaps between the metal interconnects.

[0056] In some embodiments, each microLED of the microLED array 112 may include a micromesa structure. In some embodiments, the micromesa structure may include, from bottom to top, a first type epitaxial layer, a light-emitting layer, and a second type epitaxial layer. That is, of the three layers, the first type epitaxial layer is closest to the IC backplane; the light-emitting layer is on top of the first type epitaxial layer and farther from the IC backplane; and the second type epitaxial layer is on top of the light-emitting layer and farthest from the IC backplane. In some embodiments, the light-emitting layer is formed of several stacked quantum well layers, particularly superlattice stacked quantum well layers. Preferably, the superlattice stacked quantum well layers include multiple pairs of quantum well layers stacked with quantum barrier layers. In some embodiments, the first type epitaxial layer is a semiconductor material having a first conductivity type and includes several semiconductor layers. The host material of the first type epitaxial layer may be, but is not limited to, a substrate including, but not limited to, one or more of Ga, N, As, P, In, or Al. Furthermore, the first type epitaxial layer may include, from top to bottom, a waveguide layer, a confinement layer, a transition layer, and a window layer. In addition, an ohmic contact layer may be formed below the window layer. In some embodiments, the second type epitaxial layer is a semiconductor material having a second conductivity type and includes several semiconductor layers. The host material of the second type epitaxial layer may be, but is not limited to, a substrate including, but not limited to, one or more of Ga, N, As, P, In, or Al. Furthermore, the second type epitaxial layer may include, but is not limited to, a confinement layer and a waveguide layer from top to bottom. Additionally, in some embodiments, an ohmic contact layer may be, but is not limited to, formed on the confinement layer.

[0057] In some embodiments, a top conductive layer may be formed on the top surface of the microLED array 112. In some embodiments, the top conductive layer may be shared by all microLEDs in the microLED array 112. In some embodiments, the microLED array 112 may comprise a single layer of microLEDs. For example, the microLEDs may be arranged in a planar plane. In some embodiments, the microLED array 112 may comprise multiple layers of microLEDs stacked vertically with an electrical connection layer. Each microLED in the microLED array 112 can be controlled separately by independently controlling the anode and cathode of each microLED, or controlling the individual cathode and common anode electrode layers of the microLEDs, or controlling the individual anode and cathode electrode layers of the microLEDs. For example, the microLEDs may be arranged in several planes parallel to each other.

[0058] Figure 7 A flowchart illustrating an exemplary method 70 for manufacturing a micro LED display panel according to some embodiments of the present disclosure is shown. Figure 7As shown, method 70 includes steps 702 and 704, which can be implemented by a manufacturing apparatus for manufacturing micro LED display panels (e.g., manufacturing equipment including chip mounters, wire bonding machines, molding machines, cutting machines, etc.).

[0059] In step 702, the manufacturing apparatus can couple a flexible circuit board (FCB) to a micro LED chip. (As in combination) Figures 1A to 6 The micro-LED chip includes a driving layer and a micro-LED array disposed on the driving layer. The driving layer may include a signal area thereon where no micro-LED array is disposed. The signal area can be used to receive signals for driving the micro-LED array. Furthermore, the manufacturing apparatus may arrange an FCB adjacent to the signal area and couple it to the signal area in the connection region of the FCB.

[0060] In some implementations, the FCB includes conductive traces extending from the connection area. The FCB can be coupled to the signal area via these traces. In step 702, the molding layer is further configured to encapsulate the traces.

[0061] In step 704, the manufacturing apparatus forms a molding layer to combine the microLED chip and FCB into a single compact structure and leaves an opening area above the microLED array.

[0062] In step 706, the manufacturing apparatus may provide a transparent cover within the opening area to cover the top surface of the micro-LED array.

[0063] In some embodiments of this disclosure, method 70 may further include the step of: providing a light-shielding layer on a metal pad, the metal pad being disposed in a signal area on the front surface of the drive layer, the step of which may be performed by a manufacturing apparatus.

[0064] In some embodiments of this disclosure, method 70 may further include the step of: configuring a substrate layer in conjunction with a molding layer to bond the microLED chip to at least a portion of the FCB, a step which may be performed by a manufacturing apparatus. This step may be performed prior to configuring the molding layer in step 704. In this step, the connection area of ​​the molding layer, the microLED chip, and the FCB may be disposed on the front surface of the substrate layer.

[0065] Other aspects of method 70 can be found by referring to Figures 1A to 6 The above description is sufficient for understanding, and will not be elaborated further here.

[0066] Some embodiments of this disclosure also provide a display device. The display device may include any of the micro LED display panels described herein.

[0067] Figure 8Exemplary display devices are shown according to some embodiments of this disclosure. For example... Figure 8 As shown, a Near Eye Display (NED) 800, such as AR glasses, includes a pair of color projectors 810 and a frame 820 for fixing the color projectors 810. The NED 800 may also include other components, which are omitted here for clarity of the NED 800 configuration. Each color projector 810 may be disposed at the end of a temple (not shown) of the NED 800. A power supply system and processing system for driving the color projectors 810 may be embedded in the temple. The image rendered by each color projector 810 can be captured by the corresponding eye of an observer (not shown), which can be used to create a virtual or augmented scene for the observer. In some embodiments, the term "rendering" may also be referred to as "display," "shown," or equivalent terms. Each color projector 810 may include three micro-LED panels of different colors (e.g., each corresponding to...). Figure 1A , 1B Miniature LED display panel 10 in 2A and 2B or Figure 4A and 4B The image consists of a miniature LED display panel 40 and a combiner (e.g., a combination prism). The combiner can be used to combine (also called “composite”) images rendered by three miniature LED panels into a composite image.

[0068] Figure 9 Another exemplary display device is shown, illustrating some embodiments according to this disclosure. For example... Figure 9 As shown, the head-mounted virtual reality device 900 includes two micro-LED panels 910 (e.g., each corresponding to...). Figure 1A , 1B Miniature LED display panel 10 in 2A and 2B or Figure 4A and 4B The head-mounted virtual reality device 900 may also include a micro-LED display panel 40 (not shown), although it may also include a central processing unit (CPU), a graphics processing unit (GPU) as a signal source, and other related circuitry. Introducing a micro-LED panel embodying the aforementioned micro-LED elements into the head-mounted virtual reality device 900 can improve its illumination efficiency, thereby reducing energy consumption and improving image quality.

[0069] 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 “including,” “having,” “containing,” and “comprising,” as well as other similar forms, are intended to be equivalent in meaning and are open-ended; one or more items following any of these words do not imply an exhaustive list of such one or more items, or that they are limited to only one or more listed items.

[0070] Unless otherwise specified, the term "or" as used herein includes all possible combinations except where it is impractical. For example, if a database is declared to include A or B, then unless otherwise specified or impractical, the database may include A, or B, or A and B. A second example is if a database is declared to include A, B, or C, then unless otherwise specified 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.

[0071] In the foregoing specification, numerous specific details have been described with reference to embodiments that may vary depending on the implementation. Certain adjustments and modifications may be made to the described embodiments. Other embodiments will be apparent to those skilled in the art in light of the specification and practice of the invention disclosed herein. The specification and embodiments are intended to be considered exemplary only, and the following claims indicate the true scope and spirit of the invention. It is also intended that the order of steps shown in the figures is for illustrative purposes only and is not intended to limit one to any particular order of steps. Therefore, those skilled in the art will understand that these steps may be performed in a different order when implementing the same method.

[0072] 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 display panel, characterized in that, include: A micro LED chip includes a driving layer and a micro LED array disposed on the driving layer, the driving layer being configured to receive signals for driving the micro LED array; A flexible circuit board (FCB) is disposed adjacent to the micro LED chip and configured to be coupled to the micro LED chip; A molding layer is disposed on the micro LED chip and the FCB to bond the micro LED chip and the FCB together, thereby leaving an opening area above the micro LED array; as well as A transparent cover is disposed within the opening area to shield the top surface of the micro-LED array.

2. The micro LED display panel according to claim 1, characterized in that, The driving layer also includes a signal area, on which the micro LED array is not disposed, and the FCB is disposed adjacent to and coupled to the signal area.

3. The micro LED display panel according to claim 2, characterized in that, The FCB also includes a connection area adjacent to the signal area, and The micro LED display panel also includes conductive lines connecting the connection area and the signal area.

4. The micro LED display panel according to claim 1, characterized in that, The transparent cover is spaced apart from the top surface of the micro-LED array.

5. The micro LED display panel according to claim 1, characterized in that, The transparent cover includes an adhesive layer that adheres to the driving layer around the top surface of the micro-LED array.

6. The micro LED display panel according to claim 5, characterized in that, The adhesive layer is formed of epoxy adhesive, thermosetting adhesive or water-based adhesive (moisture adhesive).

7. The micro LED display panel according to claim 5, characterized in that, The driver layer also includes: Metal pads on the front surface of the drive layer; and A light-shielding layer is disposed on the metal pad.

8. The micro LED display panel according to claim 7, characterized in that, The metal pads and the light-shielding layer are formed around the micro-LED array.

9. The micro LED display panel according to claim 8, characterized in that, The adhesive layer is formed on the top surface of the light-shielding layer.

10. The micro LED display panel according to claim 1, characterized in that, The side surface of the transparent cover is spaced apart from the molded layer.

11. The micro LED display panel according to claim 2, characterized in that, Also includes: A substrate layer, disposed in conjunction with the molding layer, is provided to bond the microLED chip to at least a portion of the FCB, wherein the molding layer, the microLED chip, and the FCB are disposed on the front surface of the substrate layer.

12. The micro LED display panel according to claim 11, characterized in that, The substrate layer is formed of a steel plate.

13. The micro LED display panel according to claim 11, characterized in that, The FCB includes an adhesive layer that adheres to the surface of the substrate layer, the bottom surface of which is aligned with the bottom surface of the microLED chip.

14. The micro LED display panel according to claim 13, characterized in that, The adhesive layer is conductive.

15. The micro LED display panel according to claim 13, characterized in that, The adhesive layer is a first adhesive layer, and the driving layer further includes a second adhesive layer adhered to the surface of the substrate layer, the bottom surface of the second adhesive layer being aligned with the bottom surface of the FCB.

16. The micro LED display panel according to claim 15, characterized in that, The second adhesive layer is insulating.

17. The micro LED display panel according to claim 16, characterized in that, The second adhesive layer is formed by die attach (DA) adhesive or die attach film (DAF) adhesive.

18. The micro LED display panel according to claim 15, characterized in that, The thickness of the first adhesive layer is less than the thickness of the second adhesive layer.

19. The micro LED display panel according to claim 13, characterized in that, The FCB is coupled to the signal region within the connection region of the FCB, the adhesive layer is disposed on the bottom surface of the connection region, and the substrate layer is disposed below the connection region via the adhesive layer.

20. The micro LED display panel according to claim 19, characterized in that, The adhesive layer is also disposed below the bottom surface of the region adjacent to the connection area, and the substrate layer is further disposed below the adjacent region via the adhesive layer.

21. The micro LED display panel according to claim 20, characterized in that, The molding layer is also formed on the FCB at a distance extending from the connection area.

22. The micro LED display panel according to claim 21, characterized in that, The distance is equal to or different from the length of the adjacent region.

23. The micro LED display panel according to claim 22, characterized in that, The distance is at least 0.05 mm longer than the length of the adjacent region.

24. The micro LED display panel according to claim 2, characterized in that, The FCB is coupled to the signal region in the connection area of ​​the FCB, the FCB includes a conductive line leading out from the connection area, and the FCB is coupled to the signal region via the line.

25. The micro LED display panel according to claim 24, characterized in that, The molding layer is also configured to encapsulate the circuitry.

26. The micro LED display panel according to claim 1, characterized in that, The bottom surface of the micro LED chip is aligned with the bottom surface of the FCB.

27. The micro LED display panel according to claim 1, characterized in that, The height of the molded layer is greater than or equal to the height of the micro-LED array.

28. The micro LED display panel according to claim 2, characterized in that, The FCB is coupled to the signal area within the connection area of ​​the FCB, the width of the molding layer corresponds to the width of the connection area, and the width of the molding layer is greater than the width of all areas of the FCB except the connection area.

29. The micro LED display panel according to claim 1, characterized in that, It also includes a rigid circuit board disposed on the FCB at the opposite end to the micro LED chip and electrically coupled to the FCB, the rigid circuit board including at least one connector disposed on the surface of the rigid circuit board.

30. The micro LED display panel according to claim 29, characterized in that, The rigid circuit board also includes a memory chip, and the at least one connector is coupled to the memory chip.

31. A method for manufacturing a micro LED display panel, characterized in that, include: A flexible circuit board (FCB) is coupled to a micro LED chip, the micro LED chip including a driving layer and a micro LED array disposed on the driving layer, the driving layer being configured to receive signals for driving the micro LED array, and the FCB being disposed adjacent to the micro LED chip and configured to be coupled to the micro LED chip; A molding layer is formed to combine the microLED chip with the FCB into a single structure, leaving an opening area above the microLED array; as well as A transparent cover is provided within the opening area to cover the top surface of the micro-LED array.

32. The method according to claim 31, characterized in that, The driving layer further includes a signal area on which the micro LED array is not disposed, and the FCB is disposed adjacent to the signal area and coupled to the signal area.

33. The method according to claim 32, characterized in that, The FCB also includes a connection area adjacent to the signal area, and The micro LED display panel also includes conductive lines connecting the connection area and the signal area.

34. The method according to claim 31, characterized in that, Also includes: A light-shielding layer is provided on the metal pads arranged on the front surface of the drive layer.

35. The method according to claim 31, characterized in that, Before forming the molded layer, the method further includes: A substrate layer is disposed on at least a portion of the FCB and on the back side of the microLED chip, the substrate layer cooperating with the molding layer to bond the microLED chip to the FCB.

36. The method according to claim 32, characterized in that, The FCB includes conductive lines extending from the connection area, and the FCB is configured to be coupled to the signal area via the lines.

37. The method according to claim 36, characterized in that, The molding layer is further formed to encapsulate the circuit.

38. A display device, characterized in that, Includes a micro LED display panel according to any one of claims 1 to 30.

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