Display module, preparation method thereof and display device

Abstract

The application belongs to the technical field of display, and discloses a display module, a preparation method thereof and a display device. The display module comprises a micro display screen body, a flexible circuit board, a metal boss and an adhesive. The micro display screen body comprises a first substrate, and a display area is arranged on the first substrate. A plurality of parallel and spaced PADs are arranged on one side of the display area, and the PADs are recessed on the first substrate. The flexible circuit board comprises a second substrate, and a plurality of gold fingers are arranged on the second substrate. The plurality of gold fingers correspond to the plurality of PADs one by one. The metal boss is provided with a plurality of first ends, and the first ends are abutted to the PADs. The second ends of the metal boss protrude from the first substrate. The adhesive is used to connect the second ends of the metal boss and the gold fingers. The application also provides a preparation method of the display module, and the preparation efficiency of the metal boss is improved. The application also provides a display device, which comprises the above display module and has high use reliability.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a display module, its manufacturing method, and a display device. Background Technology

[0002] In recent years, with the development of display technology and the rise of the metaverse concept, micro-display technology has received widespread attention and research. However, as display panels shrink, many technological challenges have gradually emerged, including process challenges brought about by pixel miniaturization, brightness loss caused by CF (Color Filter) during colorization, and challenges to module segment processes brought about by screen miniaturization.

[0003] FPC (Flexible Printed Circuit) is a flexible circuit board that connects the microdisplay body to the driver. A typical FPC bonding process involves aligning the exposed pads (pads) on the screen body with the gold fingers on the FPC and bonding them together using conductive adhesive. In the microdisplay field, because the bonding precision of existing module manufacturing processes cannot meet the increasingly miniaturized screen technology, display abnormalities caused by short circuits in the pads during FPC bonding frequently occur. For example, ... Figures 1-3 As shown, since the alignment and bonding accuracy of the module bonding process is generally ±20μm, and the spacing between PAD110' and Dummy area 120' (non-functional semiconductor structure) of the microdisplay body 100' is usually set to 20μm, during the fabrication process, the gold fingers 210' on the flexible circuit board 200' can easily overlap with the Dummy area 120'. The width of the metal strip in the Dummy area 120' is often greater than the width of a PAD110', which can cause adjacent gold fingers 210' to overlap, resulting in display abnormalities and low module yield.

[0004] Therefore, there is an urgent need for a display module, its manufacturing method, and a display device to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a display module and its manufacturing method, as well as a display device, which aims to solve the problem in the prior art where, when the gold fingers on the FPC are bonded to the PAD on the microdisplay body, the gold fingers on the FPC easily come into contact with the dummy area on the microdisplay body, causing short circuits between adjacent gold fingers and resulting in display abnormalities. This invention avoids contact between the gold fingers and the dummy area, effectively improving the yield of the display module.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A display module, comprising:

[0008] A microdisplay body includes a first substrate, on which a display area is disposed, and on one side of the display area are a plurality of parallel and spaced PADs, which are recessed into the first substrate, and a dummy area is disposed on the side of the PAD away from the display area.

[0009] A flexible circuit board includes a second substrate on which a plurality of parallel gold fingers are provided, and the plurality of gold fingers correspond one-to-one with a plurality of PADs;

[0010] The metal protrusion is provided in multiple ways, and each of the multiple metal protrusions corresponds to one of the multiple PADs. The first end of the metal protrusion abuts against the PAD, and the second end of the metal protrusion protrudes from the first substrate.

[0011] The adhesive component is provided in multiple ways, and each adhesive component corresponds to a gold finger. The adhesive component is used to connect the second end of the metal boss and the gold finger.

[0012] Optionally, the adhesive is a conductive adhesive.

[0013] A method for manufacturing a display module, used to manufacture a display module as described in any of the above embodiments, the method comprising:

[0014] A microdisplay body is provided, the microdisplay body includes a first substrate, a display area is provided on the first substrate, a plurality of parallel and spaced PADs are provided on one side of the display area, and the PADs are recessed on the first substrate, and a dummy area is provided on the side of the PADs away from the display area.

[0015] The first photoresist is coated and exposed and developed. The first photoresist is coated on the microdisplay body, exposed, and developed to transfer the pattern on the first mask onto the first photoresist, forming a window pattern at the metal protrusion position.

[0016] Electroplating involves immersing the micro-display body in an electroplating solution to form the metal protrusion at the window position.

[0017] Remove the first photoresist.

[0018] Optionally, before coating the first photoresist and exposing and developing it, the method further includes:

[0019] Sputtering involves bombarding the microdisplay body with high-speed ions to sputter the target material onto the surface of the microdisplay body, forming a bottom metal layer.

[0020] Optionally, after removing the first photoresist, the method further includes:

[0021] A second photoresist is applied and exposed and developed. The second photoresist is applied to the surface of the bottom metal layer and the metal boss, exposed, and developed to transfer the pattern on the second mask onto the second photoresist, forming a protective pattern for the metal boss.

[0022] Etching to remove the bottom metal layer located around the metal boss;

[0023] Remove the second photoresist.

[0024] Optionally, the microdisplay body needs to be cleaned before the sputtering.

[0025] A display device comprising a display module as described in any of the above embodiments.

[0026] The beneficial effects of the present invention are as follows: In the display module provided by the present invention, the first end of the metal boss abuts against the PAD, and the second end of the metal boss protrudes from the first substrate. When the microdisplay body and the flexible circuit board are bonded, the second end of the metal boss protrudes from the first substrate, which raises the connection point between the PAD and the gold fingers, and forms a height difference between the gold fingers and the dummy area. This avoids contact between the gold fingers and the dummy area in space, prevents short circuits between adjacent gold fingers, and effectively improves the yield of the display module.

[0027] The present invention also provides a method for preparing a display module, which uses an electroplating process to prepare metal bosses. The electroplating process has high reliability, high safety and high efficiency. By using the electroplating process, the preparation efficiency of metal bosses is improved.

[0028] The present invention also provides a display device comprising the above-described display module, which has high reliability in use. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the bonding structure between the microdisplay body and the FPC in the prior art;

[0030] Figure 2 This is a schematic diagram of the structure in the existing technology where the gold finger connects to the dummy area. Figure 1 ;

[0031] Figure 3 This is a schematic diagram of the structure in the existing technology where the gold finger connects to the dummy area. Figure 2 ;

[0032] Figure 4 This is a schematic diagram of the structure of the display module provided in an embodiment of the present invention;

[0033] Figure 5 This is a flowchart of the manufacturing method of the display module provided in the embodiments of the present invention;

[0034] Figure 6 This is a schematic diagram of the structure of the micro-display screen (display area not shown) provided in an embodiment of the present invention;

[0035] Figure 7 This is a schematic diagram of the structure provided in an embodiment of the present invention, showing the bottom metal layer formed after the microdisplay body is formed.

[0036] Figure 8 This is a schematic diagram of the structure after the first photoresist is coated on the bottom metal layer, as provided in an embodiment of the present invention;

[0037] Figure 9 This is a schematic diagram of the structure after a window pattern is formed at the position of the metal boss, provided in an embodiment of the present invention;

[0038] Figure 10 This is a schematic diagram of the structure after forming a metal boss at the window position according to an embodiment of the present invention;

[0039] Figure 11 This is a schematic diagram of the structure after removing the first photoresist according to an embodiment of the present invention;

[0040] Figure 12 This is a schematic diagram of the structure after the second photoresist is coated on the surface of the bottom metal layer and the metal boss, according to an embodiment of the present invention.

[0041] Figure 13 This is a schematic diagram of the structure after forming a protective pattern for the metal boss, provided in an embodiment of the present invention;

[0042] Figure 14 This is a schematic diagram of the structure after removing the bottom metal layer around the metal boss, as provided in an embodiment of the present invention.

[0043] Figure 15 This is a schematic diagram of the structure after removing the second photoresist according to an embodiment of the present invention.

[0044] In the picture:

[0045] 100' Micro-display body; 110' PAD; 120' Dummy area; 200' Flexible circuit board; 210' Gold fingers;

[0046] 100, Microdisplay body; 110, First substrate; 120, Display area; 130, PAD; 140, Dummy area; 200, Flexible circuit board; 210, Second substrate; 220, Gold finger; 300, Metal boss; 310, Filler; 320, Outer protrusion; 400, Adhesive; 500, First photoresist; 600, Bottom metal layer; 700, Second photoresist. Detailed Implementation

[0047] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0048] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0049] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0050] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0051] This embodiment provides a display module and its manufacturing method, as well as a display device, which aims to solve the problem in the prior art where, when the gold fingers on the FPC are bonded to the PAD on the microdisplay body, the gold fingers on the FPC easily come into contact with the dummy area on the microdisplay body, causing short circuits between adjacent gold fingers and resulting in display abnormalities. This embodiment avoids contact between the gold fingers and the dummy area, effectively improving the yield of the display module.

[0052] like Figure 4As shown, the display module includes a microdisplay body 100, a flexible circuit board 200, a metal boss 300, and an adhesive 400. The microdisplay body 100 includes a first substrate 110, on which a display area 120 is disposed. A plurality of parallel and spaced-apart PADs 130 are disposed on one side of the display area 120. Each PAD 130 is recessed into the first substrate 110. A dummy area 140 is disposed on the side of each PAD 130 away from the display area 120. The flexible circuit board 200 includes a second substrate 210, on which a plurality of parallel gold fingers 220 are disposed. Each gold finger 220 corresponds to one of the plurality of PADs 130. A plurality of metal bosses 300 are provided, each corresponding to one of the plurality of PADs 130. The first end of each metal boss 300 abuts against one of the PADs 130, and the second end of each metal boss 300 protrudes from the first substrate 110. A plurality of adhesive members 400 are provided, each corresponding to one of the plurality of gold fingers 220. The adhesive members 400 are used to connect the second end of the metal bosses 300 to the gold fingers 220.

[0053] In the display module provided in this embodiment, the first end of the metal boss 300 abuts against the PAD 130, and the second end of the metal boss 300 protrudes from the first substrate 110. When the microdisplay body 100 and the flexible circuit board 200 are bonded, the second end of the metal boss 300 protrudes from the first substrate 110, which raises the connection point between the PAD 130 and the gold finger 220, and forms a height difference between the gold finger 220 and the dummy area 140. This avoids contact between the gold finger 220 and the dummy area 140 in space, prevents short circuits between adjacent gold fingers 220, and effectively improves the yield of the display module.

[0054] In this embodiment, the metal boss 300 includes a filler 310 and an outer protrusion 320 connected to each other. One end of the filler 310 is embedded in the first substrate 110 and connected to the PAD 130. The outer protrusion 320 is disposed at the other end of the filler 310 and protrudes from the first substrate 110. The size of the outer protrusion 320 is larger than that of the filler 310, and the outer protrusion 320 is used to connect with the adhesive 400. By setting the size of the outer protrusion 320 to be larger than that of the filler 310, on the one hand, the edge of the bottom surface of the outer protrusion 320 is fully connected to the upper surface of the microdisplay body 100, and on the other hand, it ensures that the outer protrusion 320 and the adhesive 400 have a sufficiently large contact area, thereby improving the connection reliability between the outer protrusion 320 and the gold finger 220. In other embodiments, the size of the outer protrusion 320 may be the same as that of the filler 310, or the size of the outer protrusion 320 may be smaller than that of the filler 310, as long as a sufficiently effective contact area is ensured between the outer protrusion 320 and the adhesive 400.

[0055] Optionally, the height of the protrusion 320 is 1.5μm-2.5μm, preferably 2μm. This design avoids the overall thickness of the display module becoming too thick due to the excessive height of the protrusion 320, which would affect the connection with other components; and prevents the height difference between the gold fingers 220 and PAD130 from being too small due to the excessive height of the protrusion 320, which would make short circuit problems unavoidable.

[0056] In this embodiment, the adhesive 400 is a conductive adhesive, which connects the PAD130 and the gold finger 220 together, forming an electrical path between them. The conductive adhesive mainly consists of a resin matrix, conductive particles, dispersing additives, and auxiliaries. The matrix mainly includes epoxy resin, acrylic resin, polyurethane, etc.

[0057] Optionally, the metal boss 300 can be made of aluminum or copper. Both aluminum and copper have good electrical conductivity and are relatively inexpensive.

[0058] This embodiment also provides a method for manufacturing a display module, such as... Figures 5-15 As shown, the method for preparing the above-mentioned display module includes the following steps:

[0059] S1. A microdisplay body 100 is provided. The microdisplay body 100 includes a first substrate 110. A display area 120 is provided on the first substrate 110. A plurality of PADs 130 are provided on one side of the display area 120, which are parallel to each other and spaced apart. The PADs 130 are recessed into the first substrate 110. A dummy area 140 is provided on the side of the PADs 130 away from the display area 120.

[0060] S2. Coating the first photoresist 500 and exposing and developing it: Coating the first photoresist 500 on the microdisplay body 100, exposing and developing it, transferring the pattern on the first mask to the first photoresist 500, and forming a window pattern at the position of the metal protrusion 300.

[0061] S3. Electroplating: Immerse the micro-display body 100 in the electroplating solution to form a metal protrusion 300 at the window position.

[0062] The micro-display body 100 is immersed in the electroplating solution. After being energized, the metal ions in the electroplating solution move to the window position under the action of the potential difference to form metal protrusions 300.

[0063] S4. Remove the first photoresist 500.

[0064] The method for preparing the display module provided in this embodiment uses an electroplating process to prepare the metal boss 300. The electroplating process has high reliability, high safety and high efficiency. By using the electroplating process, the preparation efficiency of the metal boss 300 is improved.

[0065] In this embodiment, before coating the first photoresist 500 and exposing and developing it, the following steps are also included:

[0066] Sputtering: High-speed ions are used to bombard the microdisplay body 100, sputtering the target material onto the surface of the microdisplay body 100 to form a bottom metal layer 600.

[0067] The bottom metal layer 600 acts as a diffusion barrier layer, preventing atoms from diffusing between different materials. For example, if the target material is a titanium-tungsten-gold target, then the bottom metal layer 600 can be a gold layer and a titanium-tungsten layer.

[0068] Furthermore, after removing the first photoresist 500, the process also includes:

[0069] The second photoresist 700 is coated and exposed and developed. The second photoresist 700 is coated on the surface of the bottom metal layer 600 and the metal boss 300, exposed and developed, and the pattern on the second mask is transferred to the second photoresist 700 to form a protective pattern for the metal boss 300.

[0070] Etching removes the bottom metal layer 600 located around the metal boss 300;

[0071] Remove the second photoresist 700.

[0072] By removing the bottom metal layer 600 and the second photoresist 700 around the metal boss 300, excess bottom metal layer 600 and second photoresist 700 can be prevented from affecting the formation of the subsequent display area 120.

[0073] Preferably, the microdisplay body 100 should be cleaned before sputtering to remove impurities. For example, deionized water can be used to clean the microdisplay body 100.

[0074] This embodiment also provides a display device, which includes the above-mentioned display module, and the display device has high reliability in use.

[0075] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A display module, characterized in that, include: The microdisplay body (100) includes a first substrate (110), a display area (120) is provided on the first substrate (110), a plurality of parallel and spaced PADs (130) are provided on one side of the display area (120), the PADs (130) are recessed on the first substrate (110), and a dummy area (140) is provided on the side of the PADs (130) away from the display area (120); The flexible circuit board (200) includes a second substrate (210), on which a plurality of parallel gold fingers (220) are provided, and the plurality of gold fingers (220) and the plurality of PADs (130) correspond one-to-one; A plurality of metal bosses (300) are provided, and the plurality of metal bosses (300) correspond one-to-one with the plurality of PADs (130). The first end of the metal boss (300) abuts against the PAD (130), and the second end of the metal boss (300) protrudes from the first substrate (110). There are multiple adhesive components (400), and each adhesive component (400) corresponds to a gold finger (220). The adhesive component (400) is used to connect the second end of the metal boss (300) and the gold finger (220).

2. The display module according to claim 1, characterized in that, The adhesive (400) is a conductive adhesive.

3. A method for manufacturing a display module, characterized in that, The method for preparing the display module as described in claim 1 or 2 includes: A microdisplay body (100) is provided, the microdisplay body (100) includes a first substrate (110), a display area (120) is provided on the first substrate (110), a plurality of parallel and spaced PADs (130) are provided on one side of the display area (120), and the PADs (130) are recessed into the first substrate (110), and a dummy area (140) is provided on the side of the PADs (130) away from the display area (120); The first photoresist (500) is coated and exposed and developed. The first photoresist (500) is coated on the microdisplay body (100), exposed, and developed to transfer the pattern on the first mask to the first photoresist (500) and form a window pattern at the position of the metal boss (300). Electroplating: The microdisplay body (100) is immersed in an electroplating solution to form the metal protrusion (300) at the window position; Remove the first photoresist (500).

4. The method for preparing a display module according to claim 3, characterized in that, Before coating the first photoresist (500) and exposing and developing it, the process also includes: Sputtering: High-speed ions are used to bombard the microdisplay body (100) to sputter the target material onto the surface of the microdisplay body (100) to form a bottom metal layer (600).

5. The method for preparing a display module according to claim 4, characterized in that, After removing the first photoresist (500), the process further includes: The second photoresist (700) is coated and exposed and developed. The second photoresist (700) is coated on the surface of the bottom metal layer (600) and the metal boss (300), exposed and developed, and the pattern on the second mask is transferred to the second photoresist (700) to form a protective pattern for the metal boss (300). Etching to remove the bottom metal layer (600) located around the metal boss (300); Remove the second photoresist (700).

6. The method for preparing a display module according to claim 4, characterized in that, Before the sputtering, the microdisplay body (100) must be cleaned.

7. A display device, characterized in that, The display device includes the display module as described in claim 1 or 2.

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