A chip-on-film binding structure, display module and terminal device

Abstract

The present invention provides a chip-on-film binding structure, a display module and a terminal device, the chip-on-film binding structure comprising: a chip-on-film, comprising a first pin; a flexible circuit board, comprising a second pin, the second pin being connected to the first pin; the first pin comprising a first end and a second end opposite to each other, the second pin comprising a third end and a fourth end opposite to each other, the first end of the first pin and the third end of the second pin overlapping to form an effective contact area; the second end of the first pin and the fourth end of the second pin respectively extending from opposite sides of the effective contact area, forming a first exposed area at the second end of the first pin, and forming a second exposed area at the fourth end of the second pin. The chip-on-film binding structure, display module and terminal device of the present invention, while meeting the requirements of the FPC and COF binding process, effectively improve the problem of easy corrosion of the exposed part of the FPC pin, which is conducive to reducing poor display of the display screen, improving reliability, and increasing the service life of the product.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a chip-on-film binding structure, a display module and a terminal device. Background Art

[0002] The current OLED (organic light-emitting diode) display module process is complex. As people's demands for the diversity of its functions increase and its size is reduced, the laser cutting, binding and bonding of display modules are becoming more and more demanding, and the precision requirements of each process are getting higher and higher.

[0003] At present, COF (Chip On Film, or Chip On Flex) technology is used on OLED display modules to achieve ultra-narrow borders. Chip On Flex technology is a technology that uses thermal compression to bond the pads on the driver chip to the pins on the flexible circuit board. The flexible circuit board includes a substrate, a metal layer and a paint film. The paint film exposes both ends of the metal layer. One of the two exposed parts is bonded to the display substrate, and the other part (COF Pin) is bonded to the Pin of the flexible circuit board FPC. In the current OLED display module COF technology, there is a problem that the exposed part of the FPC pin is easily corroded, which causes the display module to produce defects, affecting the module product yield and product life. Summary of the invention

[0004] The purpose of the present invention is to provide a chip-on-film binding structure, a display module and a terminal device, which can meet the requirements of the FPC and COF binding process and effectively improve the problem of corrosion of the exposed part of the FPC pin, thereby reducing display defects of the display screen, improving reliability and increasing product service life.

[0005] The technical solution provided by the present invention is as follows:

[0006] An embodiment of the present invention provides a chip-on-film binding structure, including:

[0007] A chip-on-chip film, wherein the chip-on-chip film comprises a first pin;

[0008] And, a flexible circuit board, the flexible circuit board comprising a second pin, the second pin being connected to the first pin;

[0009] The first pin includes a first end and a second end opposite to each other,

[0010] The second pin includes a third end and a fourth end opposite to each other,

[0011] The first end of the first pin and the third end of the second pin overlap to form an effective contact area;

[0012] The second end of the first pin and the fourth end of the second pin extend from opposite sides of the effective contact area respectively, and a first exposed area is formed at the second end of the first pin, and a second exposed area is formed at the fourth end of the second pin.

[0013] Exemplarily, the first exposed area has a first length in an extending direction from the first end to the second end;

[0014] The second exposed area has a second length in an extending direction from the first end to the second end;

[0015] The first length and the second length are less than 0.3 mm.

[0016] Exemplarily, the first length is 0.05-0.20 mm.

[0017] Exemplarily, the first length is 0.1 mm.

[0018] Exemplarily, the second length is 0.1-0.2 mm.

[0019] Exemplarily, the second length is 0.1 mm.

[0020] Exemplarily, the chip-on-film includes:

[0021] substrate;

[0022] A metal layer is disposed on the substrate, and a driver IC is connected to the metal layer;

[0023] A paint film is disposed on the metal layer, wherein the paint film exposes two ends of the metal layer, and the exposed two parts are respectively the first pin and a third pin for connecting with the display substrate.

[0024] An embodiment of the present invention further provides a display module, comprising the COF binding structure as described above.

[0025] Exemplarily, the display module is an OLED display module.

[0026] An embodiment of the present invention further provides a terminal device, comprising the display module as described above.

[0027] The beneficial effects brought by the present invention are as follows:

[0028] In the above scheme, the second end of the first pin of the COF is extended out of the effective contact area between the first pin and the second pin of the flexible circuit board, that is, the first pin of the COF is designed to be longer than the effective contact area. Thus, compared with the aforementioned method in which only the FPC Pin is exposed but the COF Pin is not exposed (that is, the length of the COF Pin is equal to the length of the effective contact area), the first pin of the COF is designed to be longer than the effective contact area. Thus, since the length of the COF Pin (first pin) is lengthened, the exposed portion of the FPC Pin (second pin) can be reduced while the length of the effective contact area between the first pin and the second pin is kept unchanged, thereby achieving the improvement of the problem of easy corrosion of the exposed portion of the FPC pin while meeting the process requirements of FPC and COF Bonding, which is beneficial to reducing display defects of display screens, improving reliability, and increasing product service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram showing a structure of a chip-on-film binding structure in the prior art;

[0030] Figure 2 A schematic structural diagram of a chip-on-film binding structure provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0032] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one", "one" or "the" do not indicate quantity restrictions, but indicate that there is at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Similar words such as "connect" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0033] like Figure 1 As shown, currently, in the FOF binding process (COF and FPC binding process) of the OLED display module, COF pin2 and FPC pin1 need to ensure full contact, that is, the effective contact area between COF pin2 and FPC pin1 needs to have a certain length ( Figure 1 In the figure, A is the effective contact area. Due to the current binding device positioning and product tolerance, in order to ensure that the effective contact area A of FPC pin1 and COF pin2 has a certain length, such as Figure 1 As shown, the length of FPC Pin 1 is longer than the length of COF Pin 2. For example, Figure 1 As shown in the figure, the length of FPC Pin 1 is about 0.30mm longer than that of COF Pin 2; and one end of FPC pin 1 is flush with one end of COF pin 2, and the other end is exposed, while COF pin is not exposed at all. As time goes by, the exposed part of FPC Pin 2 will be oxidized and corroded, and even cracks will occur, causing circuit peeling and increased resistance, which will cause abnormal screen display, point defects, bright lines, etc. on the screen, as well as local heating, which will seriously affect the product yield of the module factory and the product life.

[0034] In view of the problems in the FOF binding process of OLED display devices, such as the exposed part of the FPC Pin is prone to oxidation and corrosion, which affects the product life, the embodiments of the present invention provide a flip-chip film binding structure, a display module and a terminal device, which effectively improves the problem of corrosion of the exposed part of the FPC pin while meeting the requirements of the FPC and COF binding processes, which is conducive to reducing display defects on the display screen, improving reliability and increasing product service life.

[0035] like Figure 2 As shown, a flip chip film binding structure provided by an embodiment of the present invention includes:

[0036] A chip-on-film (COF) 10, wherein the chip-on-film (COF) 10 comprises a first pin 100;

[0037] And, a flexible circuit board FPC 20, wherein the flexible circuit board FPC 20 comprises a second pin 200, and the second pin 200 is connected to the first pin 100;

[0038] The first pin 100 includes a first end and a second end opposite to each other.

[0039] The second pin 200 includes a third end and a fourth end opposite to each other.

[0040] The first end of the first pin 100 and the third end of the second pin 200 overlap to form an effective contact area A;

[0041] The second end of the first pin 100 and the fourth end of the second pin 200 extend from opposite sides of the effective contact area A respectively, and a first exposed area 100 a is formed at the second end of the first pin 100 , and a second exposed area 200 a is formed at the fourth end of the second pin 200 .

[0042] In the above scheme, the second end of the first pin 100 of the COF 10 is extended out of the effective contact area A between the first pin 100 and the second pin 200 of the flexible circuit board FPC 20, that is, the first pin 100 of the COF 10 is designed to have a length greater than the length of the effective contact area A. Compared with the aforementioned method in which only the FPC Pin is exposed but the COF Pin is not exposed (that is, the length of the COF Pin is equal to the length of the effective contact area), the first pin 100 of the COF 10 is designed to have a length greater than the length of the effective contact area A. In this way, since the length of the COF Pin (first pin 100) is lengthened, while the length of the effective contact area A of the first pin 100 and the second pin 200 is kept unchanged, the exposed portion of the FPC Pin (second pin 200) can be reduced, thereby achieving the improvement of the problem of easy corrosion of the exposed portion of the FPC pin while meeting the process requirements of FPC and COF Bonding, which is beneficial to reducing display defects of display screens, improving reliability, and increasing product service life.

[0043] In an exemplary embodiment, the first exposed area 100a has a first length L1 in the extension direction from the first end to the second end; the second exposed area 200a has a second length L2 in the extension direction from the third end to the fourth end; the first length L1 and the second length L2 are less than 0.3 mm.

[0044] like Figure 1 As shown, in one embodiment of the FPC and COF design, the length of FPC Pin 1 is 0.30 mm longer than COF Pin 2 to ensure the effective pin contact area. Figure 2 In the solution, the length of the second exposed area 200a of the FPC Pin (ie, the second pin 200) exposed outside the effective contact area A can be less than 0.3 mm.

[0045] Exemplarily, the first length L1 is 0.05-0.20 mm; exemplary, the second length L2 is 0.1-0.2 mm.

[0046] With the above solution, the length of the first pin 100 extending outside the effective contact area A can be between 0.05 and 0.20 mm, and the length of the second pin 200 extending outside the effective contact area A can be between 0.1 and 0.2 mm.

[0047] Preferably, the first length L1 is 0.1 mm; the second length L2 is 0.1 mm.

[0048] Using the above Figure 2 In the solution, the length of COF Pin and FPC pin are both 0.1mm longer than the length of effective contact area A. Compared with the prior art, the length of FPC pin can be reduced by 0.2mm and the length of COF pin can be increased by 0.1mm while the length of effective contact area A remains unchanged. This not only meets the process conditions but also prevents corrosion of FPC Pin, which is beneficial to reduce display defects of display screens and increase product service life.

[0049] Table 1 shows the difference between the FPC pin length designed to be 0.3 mm longer than the COF pin and the above embodiment. Figure 2 The reliability results are compared with the COF 10 bonding structure shown.

[0050] Item Chip-on-film binding structure in the prior art Chip-on-film binding structure according to an embodiment of the present invention 8585 operation 2 / 15Pin corrosion No corrosion THO 2 / 15Pin corrosion No corrosion

[0051] Table 1

[0052] Using 8585 operation (i.e. double 85 test, which refers to aging test under the conditions of high temperature 85℃ and relative humidity 85%) and THO (i.e. high temperature and high temperature operation test, which refers to aging test under the conditions of high temperature 60℃ and relative humidity 90%), as shown in Table 1, it can be seen that Figure 1 When the FPC pin length is designed to be 0.3 mm longer than the COF pin, 2 / 15 of the FPC Pin corrosion occurs; while the COF Pin and FPC Pin design in the COF 10 binding structure provided by the embodiment of the present invention has a very good reliability result. It can be seen that the COF 10 binding structure provided by the embodiment of the present invention can effectively prevent FPC Pin corrosion and solve the problem of poor display screen caused by FPC Pin corrosion.

[0053] In an exemplary embodiment of the present invention, Figure 2 As shown, the chip-on-film COF 10 includes:

[0054] Base 11;

[0055] A metal layer 12 is disposed on the substrate 11, and a driver IC is connected to the metal layer 12;

[0056] A paint film 13 is disposed on the metal layer 12 , and the paint film 13 exposes two ends of the metal layer 12 , wherein the exposed two parts are respectively the first pin 100 and a third pin (not shown in the figure) for connecting with a display substrate.

[0057] The COF 10 binding structure provided in the embodiment of the present invention is applicable to mobile terminals and various OLED display module structures, but is certainly not limited thereto.

[0058] In addition, an embodiment of the present invention further provides a display module, including the COF 10 binding structure provided by the embodiment of the present invention. Exemplarily, the display module is an OLED display module.

[0059] An embodiment of the present invention further provides a terminal device, comprising the display module provided by the embodiment of the present invention.

[0060] There are a few points to note:

[0061] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure, and other structures may refer to the general design.

[0062] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thickness of layers or regions is exaggerated or reduced, that is, these drawings are not drawn according to the actual scale. It is understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, the element may be "directly" "on" or "under" the other element or there may be intermediate elements.

[0063] (3) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to obtain new embodiments.

[0064] The above description is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. The protection scope of the present disclosure shall be based on the protection scope of the claims.

Claims

1. A chip-on-film binding structure, comprising: A chip-on-chip film, wherein the chip-on-chip film comprises a first pin; And, a flexible circuit board, the flexible circuit board comprises a second pin, the second pin is connected to the first pin; characterized in that, The first pin includes a first end and a second end opposite to each other, The second pin includes a third end and a fourth end opposite to each other, The first end of the first pin and the third end of the second pin overlap to form an effective contact area; The second end of the first pin and the fourth end of the second pin extend from opposite sides of the effective contact area respectively, and a first exposed area is formed at the second end of the first pin, and a second exposed area is formed at the fourth end of the second pin; The first exposed area has a first length in an extending direction from the first end to the second end; The second exposed area has a second length in an extending direction from the third end to the fourth end; The first length and the second length are less than 0.3 mm; wherein, The first length is 0.05-0.20 mm; the second length is 0.1-0.2 mm.

2. The chip-on-film binding structure according to claim 1, characterized in that: The first length is 0.1 mm.

3. The chip-on-film binding structure according to claim 1, characterized in that: The second length is 0.1 mm.

4. The chip-on-film binding structure according to claim 1, characterized in that: The flip chip film comprises: substrate; A metal layer is disposed on the substrate, and a driver IC is connected to the metal layer; A paint film is disposed on the metal layer, wherein the paint film exposes two ends of the metal layer, and the exposed two parts are respectively the first pin and a third pin for connecting with the display substrate.

5. A display module, characterized in that: It comprises the chip-on-film binding structure as claimed in any one of claims 1 to 4.

6. The display module according to claim 5, characterized in that: The display module is an OLED display module.

7. A terminal device, characterized in that: Comprising the display module as described in claim 5 or 6.

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