阅读说明：本技术 一种fpc与tft的绑定方法及显示模组 (Binding method of FPC and TFT and display module ) 是由 陈致临 于 2021-09-27 设计创作，主要内容包括：本发明公开一种FPC与TFT的绑定方法及显示模组,方法包括步骤：在ACF中混合设定量的有机矽烷,形成贴合胶；利用点胶机在所述FPC的贴合部位点上所述贴合胶；利用绑定设备绑定所述FPC和所述TFT,其中所述TFT的用于绑定所述FPC的基板为玻璃基板；利用固化机固化所述FPC和所述TFT之间的所述贴合胶。本发明中,将有机矽烷混合在ACF中后,有机矽烷与ACF发生作用而生成矽醇基,该矽醇基可与玻璃表面的矽醇基形成强的醚键,从而增强FPC与TFT绑定时的附着力,大大提高TFT的可靠性。(The invention discloses a binding method of an FPC (flexible printed circuit) and a TFT (thin film transistor) and a display module, wherein the method comprises the following steps: mixing a set amount of organosilane in the ACF to form a bonding glue; adhering the adhesive on the adhering part of the FPC by using a dispenser; binding the FPC and the TFT by using binding equipment, wherein a substrate of the TFT for binding the FPC is a glass substrate; and curing the bonding glue between the FPC and the TFT by using a curing machine. In the invention, after the organosilane is mixed in the ACF, the organosilane reacts with the ACF to generate silanol groups, and the silanol groups can form strong ether bonds with the silanol groups on the surface of the glass, thereby enhancing the adhesive force when the FPC and the TFT are bound and greatly improving the reliability of the TFT.)

1. A binding method of FPC and TFT is characterized by comprising the following steps:

mixing a set amount of organosilane in the ACF to form a bonding glue;

adhering the adhesive on the adhering part of the FPC by using a dispenser;

binding the FPC and the TFT by using binding equipment, wherein a substrate of the TFT for binding the FPC is a glass substrate;

and curing the bonding glue between the FPC and the TFT by using a curing machine.

2. The FPC and TFT bonding method of claim 1, wherein the volume ratio of the ACF to the organosilane is greater than 1.

3. The FPC and TFT bonding method of claim 2, wherein the volume ratio of the ACF to the organosilane is 8.5-9.3: 1.

4. The FPC and TFT bonding method of claim 3, wherein the bonding paste has a thickness of 2-4 μm.

5. The bonding method of the FPC and the TFT according to claim 3, wherein dots are arranged in the bonding glue between the FPC and the TFT, and the number of the conductive gold balls contained in the bonding glue is not less than 20.

6. A display module, comprising:

a TFT including a glass substrate;

and the FPC is bound with the glass substrate through bonding glue, wherein the bonding glue comprises ACF and organosilane mixed in the ACF.

7. The display module of claim 6, wherein the volume ratio of ACF to organosilane is greater than 1.

8. The display module of claim 7, wherein the volume ratio of ACF to organosilane is 8.5-9.3: 1.

9. The display module of claim 8, wherein the thickness of the adhesive is 2-4 μm.

10. The display module of claim 8, wherein dots are disposed in the adhesive between the FPC and the TFT, and the number of the conductive gold balls is not less than 20.

Technical Field

The invention relates to the technical field of display, in particular to a binding method of an FPC (flexible printed circuit) and a TFT (thin film transistor) and a display module.

Background

Although the TFT-LCD industry is a very mature industry, there are more or less difficult problems due to process limitations and design defects. For example, the adhesive used for bonding the FPC and the TFT is an ACF, and the ACF fixes and electrically connects the FPC and the TFT.

However, ACF has poor adhesiveness, and thus the FPC is easily loosened and even detached from the TFT. Therefore, a series of problems can be generated, such as transfer printing inner dirt, Cgd, parasitic capacitance, via hole corrosion, electrostatic damage, flicker, binding failure or ghost shadow and the like, the service performance and the service life of the TFT-LCD are influenced, and the user experience is reduced.

Disclosure of Invention

The invention discloses a binding method of an FPC (flexible printed circuit) and a TFT (thin film transistor) and a display module, which are used for solving the problem of poor binding firmness of the FPC and the TFT in the prior art.

In order to solve the problems, the invention adopts the following technical scheme:

a binding method of FPC and TFT is provided, which comprises the following steps:

mixing a set amount of organosilane in the ACF to form a bonding glue;

adhering the adhesive on the adhering part of the FPC by using a dispenser;

binding the FPC and the TFT by using binding equipment, wherein a substrate of the TFT for binding the FPC is a glass substrate;

and curing the bonding glue between the FPC and the TFT by using a curing machine.

Optionally, the volume ratio of the ACF to the organosilane is greater than 1.

Optionally, the volume ratio of the ACF to the organosilane is 8.5-9.3: 1.

Optionally, the thickness of the adhesive is 2-4 μm.

Optionally, the conductive gold balls are disposed in the adhesive between the FPC and the TFT, and the number of the conductive gold balls is not less than 20.

Still provide a display module assembly, include:

a TFT including a glass substrate;

an FPC bonded with the TFT by a bonding paste, wherein the bonding paste includes ACF and an organosilane mixed in the ACF.

Optionally, the volume ratio of the ACF to the organosilane is greater than 1.

Optionally, the volume ratio of the ACF to the organosilane is 8.5-9.3: 1.

Optionally, the thickness of the adhesive is 2-4 μm.

Optionally, the conductive gold balls are disposed in the adhesive between the FPC and the TFT, and the number of the conductive gold balls is not less than 20.

The technical scheme adopted by the invention can achieve the following beneficial effects:

after the organosilane is mixed in the ACF, the organosilane and the ACF react to generate silanol groups, and the silanol groups can form strong ether bonds with the silanol groups on the surface of the glass substrate, so that the adhesive force of the FPC and the TFT during binding is enhanced, the conditions of FPC binding failure or falling off and the like are effectively avoided, the problems of pad printing internal dirt, Cgd, parasitic capacitance, via hole corrosion, electrostatic shock, flicker, binding realization or ghost shadow and the like are greatly reduced, and the reliability of the TFT is greatly improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below to form a part of the present invention, and the exemplary embodiments and the description thereof illustrate the present invention and do not constitute a limitation of the present invention. In the drawings:

FIG. 1 is a flow chart of a method for bonding FPC and TFT according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a display module according to an embodiment of the disclosure.

Wherein the following reference numerals are specifically included in figures 1-2:

TFT-1; FPC-2; adhesive-3; a substrate-11; conductive gold ball-31.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The method for binding the FPC2 and the TFT1 disclosed by the invention specifically comprises the following steps as shown in figures 1 and 2:

step S10, mixing a predetermined amount of organosilane into the ACF to form a bonding paste 3;

step S20, attaching glue 3 to the attachment site of the FPC2 by a glue dispenser;

step S30, binding the FPC2 and the TFT1 with a binding device, wherein the substrate 11 of the TFT1 for binding the FPC2 is a glass substrate 11;

in step S40, the bonding paste 3 between the FPC2 and the TFT1 is cured by a curing machine.

In the method for bonding the FPC2 and the TFT1, an ACF (Anisotropic Conductive Film) is called an Anisotropic Conductive adhesive, and the main components of the ACF are two major components, namely a resin adhesive and Conductive gold balls 31. The ACF is characterized in that the resistance characteristics of the Z-axis electrical conduction direction and the XY insulation plane have obvious differences, and when the difference between the Z-axis conduction resistance value and the XY insulation resistance value exceeds a certain ratio, the ACF is called as good conduction anisotropy, so that the anisotropic conduction characteristics of the ACF mainly depend on the filling rate of the conductive gold balls 31. However, although the conductivity of the ACF increases as the filling rate of the conductive gold balls 31 increases, the probability of short circuit caused by the contact of the conductive gold balls 31 is also increased. Therefore, in the ACF, the filling rate of the conductive gold balls 31 is strictly limited.

The organosilane is a kind of organosilicon resin, the organosilicon resin is a high molecular polymer containing a silicon-oxygen bond in the main chain and an organic group, and the organosilane is a low molecular weight organosilicon polymer, i.e. liquid silicone oil. When the organosilane is mixed in the ACF under the normal temperature state, the organosilane and the ACF react to generate silanol groups, the silanol groups can form strong ether bonds with the silanol groups on the surface of the glass substrate 11, namely, the ACF mixed with the organosilane forms chemical covalent bonds between the FPC2 and the TFT1, the bonding strength of the adhesive 3 is greatly improved, the adhesive force when the FPC2 and the TFT1 are bonded is enhanced, the conditions of bonding failure or falling off of the FPC2 are effectively avoided, the problems of transfer printing internal stain, Cgd, parasitic capacitance, via hole corrosion, electrostatic shock, flicker, bonding failure or ghost shadow and the like are greatly reduced, and the reliability of the TFT1 is greatly improved.

The content of the conductive gold balls 31 in the ACF is limited, and when a large amount of organosilane is mixed in the ACF, although the bonding strength between the FPC2 and the TFT1 is increased, the conductive performance between the FPC2 and the TFT1 is affected by reducing the content of the conductive gold balls 31. Therefore, the volume of the organic silane mixed in the ACF is smaller than that of the ACF, that is, the volume ratio of the ACF to the organic silane is greater than 1, so as to improve the binding firmness between the FPC2 and the TFT1 as much as possible while ensuring the conductivity between the FPC2 and the TFT 1.

Further, in a preferred example, the volume ratio of ACF to organosilane is 8.5-9.3: 1. At this time, the number of the conductive gold balls 31 between the FPC2 and the TFT1 is not less than 20, so that good conductivity is formed between the FPC2 and the TFT1, and the bonding firmness between the FPC2 and the TFT1 meets requirements.

When the FPC2 needs to be bonded, firstly, the ACF mixed with the organosilane is dotted on the FPC2 by a dispenser, then the ACF mixed with the organosilane is pressurized and heated for about 2-10s in the environment of (3-10) x 104Pa and 60-100 ℃, then the FPC2 is mounted on the glass substrate 11 of the TFT1 by a bonding device, the conductive gold ball 31 is extruded and broken in the environment of about (20-40) x 104Pa and 150-200 ℃, so that the FPC2 and the TFT1 are conducted, and finally, the ACF mixed with the organosilane is cured by a curing machine, so that the bonding of the FPC2 and the TFT1 is completed. Wherein, the curing machine can be an ultraviolet lamp tube curing machine and the like. After the FPC2 and the TFT1 are bound, the thickness H of glue between the FPC2 and the TFT1 is 2-4 μm, so that the bonding firmness of the FPC2 and the TFT1 is improved on the basis of ensuring the conductivity of the FPC2 and the TFT 1.

The display module of the invention comprises a TFT1 and an FPC 2. The TFT1 includes a glass substrate 11. The FPC2 is bonded to the glass substrate 11 by the adhesive 3. The adhesive 3 includes ACF and organosilane mixed in the ACF, and the adhesive 3 enhances the bonding strength between the FPC2 and the TFT1, thereby improving the reliability of the TFT 1.

The ACF is called Anisotropic Conductive Film, and its main components are resin adhesive and Conductive gold ball 31. The ACF is characterized in that the resistance characteristics of the Z-axis electrical conduction direction and the XY insulation plane have obvious difference, when the difference between the Z-axis conduction resistance value and the XY insulation plane resistance value exceeds a certain ratio, the ACF is called to have good conduction anisotropy, and therefore the anisotropic conduction characteristic of the ACF mainly depends on the filling rate of the conductive particles. However, although the conductivity of the ACF increases with the increase of the filling rate of the conductive gold balls 31, the probability of short circuit caused by the contact between the conductive gold balls 31 is also increased. Therefore, in the ACF, the filling rate of the conductive gold balls 31 is strictly limited.

The organosilane is a kind of organosilicon resin, the organosilicon resin is a high molecular polymer containing a silicon-oxygen bond in the main chain and an organic group, and the organosilane is a low molecular weight organosilicon polymer, i.e. liquid silicone oil. When the organosilane is mixed in the ACF under the normal temperature state, the organosilane and the ACF react to generate silanol groups, the silanol groups can form strong ether bonds with the silanol groups on the surface of the glass substrate 11, namely, the ACF mixed with the organosilane forms chemical covalent bonds between the FPC2 and the TFT1, the bonding strength of the adhesive 3 is greatly improved, the adhesive force when the FPC2 and the TFT1 are bonded is enhanced, the conditions of bonding failure or falling off of the FPC2 are effectively avoided, the problems of transfer printing internal stain, Cgd, parasitic capacitance, via hole corrosion, electrostatic shock, flicker, bonding failure or ghost shadow and the like are greatly reduced, and the reliability of the TFT1 is greatly improved.

The content of the conductive gold balls 31 in the ACF is limited, and when a large amount of silane is mixed in the ACF, although the bonding strength between the FPC2 and the TFT1 is increased, the conductive performance between the FPC2 and the TFT1 is affected by the decrease in the content of the conductive gold balls 31. Therefore, the volume of the organic silane mixed in the ACF is smaller than that of the ACF, that is, the volume ratio of the ACF to the organic silane is greater than 1, so as to improve the binding firmness between the FPC2 and the TFT1 as much as possible while ensuring the conductivity between the FPC2 and the TFT 1.

Further, in a preferred example, the volume ratio of ACF to organosilane is 8.5-9.3: 1. At this time, the number of the conductive gold balls 31 between the FPC2 and the TFT1 is not less than 20, so that good conductivity is formed between the FPC2 and the TFT1, and the bonding firmness between the FPC2 and the TFT1 meets requirements.

When the FPC2 needs to be bonded, firstly, the ACF mixed with the organosilane is dotted on the FPC2 by a dispenser, then the ACF mixed with the organosilane is pressurized and heated for about 2-10s in the environment of (3-10) x 104Pa and 60-100 ℃, then the FPC2 is mounted on the glass substrate 11 of the TFT1 by a bonding device, the conductive gold ball 31 is extruded and broken in the environment of about (20-40) x 104Pa and 150-200 ℃, so that the FPC2 and the TFT1 are conducted, and finally, the ACF mixed with the organosilane is cured by a curing machine, so that the bonding of the FPC2 and the TFT1 is completed. Wherein, the curing machine can be an ultraviolet lamp tube curing machine and the like. After the FPC2 and the TFT1 are bound, the thickness H of glue between the FPC2 and the TFT1 is 2-4 μm, so that the bonding firmness of the FPC2 and the TFT1 is improved on the basis of ensuring the conductivity of the FPC2 and the TFT 1.

While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.