KR102047225B1

KR102047225B1 - non-conductive type adhesive means and display device using the same

Info

Publication number: KR102047225B1
Application number: KR1020120138222A
Authority: KR
Inventors: 윤여오; 박동식; 황재철; 박은주; 신성의; 박정범; 송혜선; 손아람
Original assignee: 엘지디스플레이 주식회사
Priority date: 2012-11-30
Filing date: 2012-11-30
Publication date: 2019-11-22
Also published as: KR20140072325A

Abstract

The present invention comprises a resin serving as a base; At least one material of a coupling agent or an adhesion improving agent having an affinity with a surface of a panel for a display device and a surface of a chip on film (COF); Provided are a non-conductive paste (NCP) type adhesive means including conductive particles and a display device having the same.

Description

Non-conductive type adhesive means and display device using the same}

The present invention relates to an NCP type adhesive means used when mounting a display device panel and a printed circuit board for driving the same through a COF (chip on film). The present invention can improve adhesion and suppress COF peeling. The present invention relates to a non-conductive paste (NCP) type adhesive means capable of improving the electrical conductivity between a panel and COF, and a display device having the same.

In recent years, as the society enters the full-scale information age, the display field that processes and displays a large amount of information has been rapidly developed. In recent years, as a flat panel display device having excellent performance of thinning, light weight, and low power consumption, Liquid crystal displays or organic light emitting diodes have been developed to replace conventional cathode ray tubes (CRTs).

Among the liquid crystal display devices, an active matrix liquid crystal display device including an array substrate having a thin film transistor, which is a switching element capable of controlling voltage on and off, is realized in each pixel. Excellent ability is attracting the most attention.

In addition, the organic light emitting diode has a high brightness and low operating voltage characteristics, and because it is a self-luminous type that emits light by itself, it has a high contrast ratio, an ultra-thin display, and a response time of several microseconds ( Iii) It is easy to implement a moving image, there is no limit of viewing angle, it is stable even at low temperature, and it is attracting attention as a flat panel display device because it is easy to manufacture and design a driving circuit because it is driven at a low voltage of DC 5 to 15V.

In such a liquid crystal display and an organic light emitting device, an array substrate including a thin film transistor, which is essentially a switching element, is configured to remove each of the pixel areas on and off. In the non-display area, a printed circuit board (PCB, hereinafter referred to as PCB) having a plurality of drive integrated circuits (ICs) for driving components configured in the array substrate is a tape carrier package. package: TCP, hereinafter referred to as TCP) or COF.

At this time, the COF has a configuration in which a driving IC is connected on an FPC (flexible printed circuit board), and fine wiring can be formed, a high degree of freedom in shape, and double-sided wiring are possible. It is attracting attention as a member to let.

The configuration of the array substrate will be described in more detail.

A plurality of gate pad electrodes and data pad electrodes connected to an external circuit, and gate and data link wirings connected to the plurality of gate pad electrodes and data link electrodes are formed in non-display regions on the upper and left sides of the array substrate.

In addition, a plurality of gate wires connected to each of the gate pad electrodes and the gate link wires and extending in a horizontal direction in the display area of the array substrate, and connected to the respective data pad electrodes and the data link wires and vertically connected to each other. The data lines extending in the direction cross each other to form a plurality of pixel regions.

In addition, thin film transistors are formed in the vicinity of the gate and the data wiring, and each pixel region is connected to the drain electrode of the thin film transistor and has a pixel electrode formed thereon.

On the other hand, in the case of the liquid crystal display device with respect to the array substrate having such a configuration, the color filter substrate is opposed to each other to form a liquid crystal panel by interposing the liquid crystal layer on these two substrates, and in the case of an organic light emitting device, An organic light emitting diode including a light emitting layer is formed and an opposing substrate is provided to encapsulate the organic light emitting diode, thereby forming a panel for an organic light emitting device.

In general, a driving circuit for driving an array substrate is implemented in a printed circuit board, and thus, the printed circuit board should be mounted on the panel.

That is, the printed circuit board may include a gate pad electrode connected to the gate line more precisely on one side of a panel (a liquid crystal panel or an organic light emitting diode panel) having the above-described configuration, and generally, one side on which the gate pad electrode is formed. It is formed on an orthogonal upper surface and is in contact with a data pad electrode connected to a data line, and is mounted by performing a tape automated bonding (TAB) process using TCP or COF as a medium.

1 is a diagram illustrating a step of bonding a COF to a panel during a conventional TAB process progress step of mounting a printed circuit board on the panel.

As shown in the drawing, a COF 20 is first bonded on the panel 10 prior to mounting the printed circuit board (not shown) having a plurality of driving circuits on the panel 10. After the bonding process of the COF 20 is completed, the COF 20 and the printed circuit board (not shown) are bonded to finally mount the printed circuit board (not shown) on the panel.

In this case, in order to mount the COF on the panel 10, an anisotropic conductive film (ACF) 15 having a plurality of conductive balls 18 mixed with the thermosetting resin 16 is disposed on the top of one end of the panel 10 and the COF 20. After interposed therebetween, the conductive ball 18 in the ACF 15 is pressurized by being pressed in contact with the COF 20 through a heating bar 30 that is a heating means. Hardened in such a state that the wires (not shown) provided in the P-type) and the pad electrodes (not shown) provided in the panel 10 are in contact with each other.

The ACF 15 used in the bonding process of the COF 20 proceeded in this manner is composed of a plurality of conductive balls 18 and a thermosetting resin 16 as described above, and the ACF 15 having such a configuration. When bonding the COF 20 and the panel 10 through the process temperature of 150 ℃ to 190 ℃ is usually required.

However, in the case where the bonding of the COF 20 is performed through the thermocompression method using the ACF 15 having the thermosetting property, the COF is provided on the COF 20 and connected to the driving IC due to the high temperature fluidity. (20) Reduction or non-uniformity of the effective conductive ball 18 for energizing the wiring (not shown) provided inside and the pad electrode (not shown) provided on the panel 10, and the ACF (15). Bonding surface nonuniformity by the line hardening of the thermosetting resin which comprises () has arisen.

Furthermore, in the COF 20, the double layered FPC has a circuit formed of copper, which is a low-resistance metal material, formed directly on a polyimide (PI) film, whereby the ACF 15 has a low adhesive PI. Since the adhesive is adhered to the film, when the ACF 15 is used as an adhesive, the adhesive force is reduced.

The PI surface exposed between circuits or wirings is formed by forming a metal material layer for forming copper circuits or wirings by deposition or sputtering on a PI film by using a metallization method that is optimal for high definition among FPCs having a double layer structure. Is very smooth and the adhesion strength with ACF is further reduced.

On the other hand, recently, a narrow bezel (NB) type display device having a width of about 0.5 mm to 2 mm in a non-display area has been proposed. In the case of an NB type display device having such a configuration, a polarizing plate (external visibility) (Not shown) (including a circular polarizing plate for securing) is extended to a portion where the pad electrode of the non-display area is formed.

In this case, when the COF 20 is mounted on the panel 10 by the above-described thermocompression method having a high process temperature of 150 ° C to 190 ° C, the high temperature generated when the COF 20 is bonded to the polarizing plate As a result, the polarizing plate is deformed so that the role of the polarizing plate (not shown) is deteriorated.

Therefore, in place of the ACF 15 of the thermosetting material, there is a need for an adhesive means having excellent adhesive force to maintain a state of contacting the panel with the COF 20 without requiring a high temperature process of 150 ° C. or higher.

Furthermore, recent display devices have to provide full HD display quality, and the pad electrodes provided in the panel have become smaller in width and spaced apart from each other. In this case, the conductive ball contacts the COF and the panel. When the conductive balls are placed in a state where agglomeration occurs between the pad electrodes, short circuits between adjacent pad electrodes are caused. Therefore, ACF including conductive balls is becoming increasingly impossible to use for high-definition display devices. to be.

In recent years, a large area of the display device has been increased, and in addition to having a flat display area, the display device has a concave shape in the direction in which the user looks at the display device for convenience of viewing. A curved display device having a radius of curvature and configured with a display area has been proposed.

The curved display device has a problem that the edge portion of the driving IC does not adhere to the polyimide film of the COF due to the increase in the radius of curvature of the panel source portion, and the adhered portion undergoes repeated fatigue due to continuous bending. At the same time, a problem arises in that the adhesive force is further lowered by stress concentration, and the driving IC is easily peeled from the polyimide film.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and excellent in adhesion to COF, and the COF and the panel can be cured at a low temperature of 130 ° C. or lower by excluding a high temperature thermocompression process, and further, a curved display device (curved) Even if applied to display device), we propose an adhesive means that has excellent adhesive properties and low stress characteristics with fatigue resistance, and furthermore, by adhering COF and panel by using such adhesive means, it has excellent adhesive strength and at the same time between panel and COF. It is an object of the present invention to provide a display device having excellent electrical conductivity.

NCP type adhesive means according to an embodiment of the present invention for achieving the above object is a resin as a base; At least one material of a coupling agent or an adhesion improving agent having compatibility with the surface of the display panel and the surface of a chip on film (COF); It is characterized by including electroconductive particle.

In this case, the content of the coupling agent is 1 to 3% by weight based on the total content of the non-conductive paste (NCP) -type adhesive means, the adhesion enhancer is the non-conductive paste (NCP) -type adhesive It is 3 to 9% by weight based on the total content of the means, the conductive particles are characterized in that the content of 0.1 to 4.0% by weight based on the total content of the non-conductive paste (NCP) -type adhesive means.

The coupling agent is 3-Aminopropyl diisopropyl ethoxysilane, 3-Glycidoxypropyldiisopropyl ethoxysilane, 3-Cyanopropyldiisopropylchlorosilane, n-octyldiisopropyl chlorosilane, N-methyl-3-amino propyltrimethoxysilane, N, N-dimethyl-N-octadecyl-3-aminopropyltrimethoxysilylchloride (DMOAP ) Is any one of the features.

In addition, the adhesion improving agent, characterized in that the polyester compound which is a material capable of improving the adhesion by participating in the crosslinking reaction with the base resin, wherein the polyester compound is a polyester acrylate (polyester acrylate), It is characterized in that it is any one of polyester methacrylate and polyester epoxy.

In addition, the epoxy resin is at least one material selected from the group consisting of naphthalene epoxy monomer, epoxy acrylate monomer, BPA epoxy monomer, BPF epoxy monomer, cresol epoxy monomer and novolac epoxy monomer, the acrylate The system resin is 2-ethylhexyl acrylate, tridecyl methacrylate, nonyl phenol ethoxylate monoacrylate, beta-carboxyethyl acrylate, isobornyl acrylate, tetrahydroperfuryl acrylate, tetrahydrofurfuryl methacryl At least one selected from the group consisting of latex, 4-butylcyclohexyl acrylate, dicyclopentenyl acrylate, dicyclopentenyl oxyethyl acrylate, ethoxyethyl acrylate, ethoxylated monoacrylate It is characterized by a substance.

The non-conductive paste (NCP) type adhesive means further includes an ionic curing agent and a photo curing accelerator, and has a property of curing in response to UV light, wherein the ionic curing agent and the photo curing accelerator are each NCP ( It is characterized by more than 0.01 and less than 10% by weight based on the total content of non-conductive paste) adhesive means.

In this case, the ionic curing agent is a boric acid salt (Borate) or iodine (Iodine) salt, the light curing accelerator is a light diffusion polymer material having a light diffusing function polystyrene (PS), polycarbonate (PC), polyethylene terephthalate ( PET).

A display device according to an embodiment of the present invention is a display device having an NCP (non-conductive paste) type adhesive means according to any one of claims 1 to 9, wherein the array substrate and the counter substrate A display device having a panel attached thereto; The non-conductive paste (NCP) type bonding means formed on a pad provided in a non-display area of the array substrate of the panel; And a chip on film (COF) mounted in contact with the non-conductive paste (NCP) type adhesive means.

In this case, the display device may be a flat panel display device or a curved display device having a predetermined radius of curvature and having a curved shape.

Since the adhesive means according to the embodiment of the present invention does not have a plurality of conductive balls in the interior thereof, as in the conventional ACF, the bundles of the plurality of conductive balls are formed as the width and the spacing interval of the wiring provided in the panel or the COF are narrowed. When generated, it is possible to fundamentally prevent the occurrence of short defects between neighboring wires, and by including the conductive particles in the form of particles of several to several tens of nanometers, the size of which is relatively smaller than the plurality of conductive balls, NCP. It has the effect of improving the electrical conductivity of the adhesive means of the type.

Furthermore, the NCP type adhesive means according to the embodiment of the present invention can maintain the bonded state for a long time even if it has a relatively small adhesive surface area by strengthening the adhesive force by including an appropriate amount of coupling agent or / and adhesion improving agent.

Therefore, even in an NB type display device or a large-area curved display device, the COF can be prevented from being peeled off to maintain the bonded state for a long time.

In addition, the NCP type adhesive means according to an embodiment of the present invention, when further comprises an ionic curing agent and a photo-curing accelerator, has a photocurable properties and changes the optical path, characterized in that the light diffusion occurs therein As a result, even if the bonding process of the COF and the panel is performed at a relatively low temperature (110 to 130 ° C) lower than the temperature (150 ° C to 190 ° C) required for thermal pressurization of the conventional ACF, excellent adhesion and conductivity between the COF and the panel are achieved. It has the effect of having characteristics.

Furthermore, since the bonding between the COF and the panel is performed at a low temperature process, the polarizing plate that can be provided in the panel and the COF itself are not exposed to high temperature of 130 ° C. or higher, thereby preventing deformation or dislocation of these components.

1 is a view showing a step of bonding a COF to a panel during a conventional TAB process progress step of mounting a printed circuit board on the panel.
2A and 2B show bonding of a panel and a COF using NCP type bonding means according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described.

COF is a structure in which a driving IC is connected on a double layered FPC, which enables the formation of fine wiring, high degree of freedom of shape, double-sided wiring, and easy mounting without damaging the substrate on which the fine wiring is formed. Have

When COF is bonded to the display device by electrodeposition means, the COF should be bonded to PI having high elasticity because copper wires or circuits are formed directly on the PI film on copper FPC. .

In addition, a PI surface exposed between circuits or wirings is formed by forming a metal material layer for forming a copper circuit or wiring by deposition or sputtering on a PI film by using a metallization method that is optimal for high definition among FPCs having a double layer structure. Is very smooth so that the adhesion with the bonding means is further reduced.

Therefore, in order to solve this problem, in addition to improving the chemical and electrical adhesion of the surface of the PI film by the functional group or the adhesion aid in the adhesion means, it is important to design to minimize the interfacial stress (interfacial stress).

On the other hand, in order to bond the COF to the panel of the display device by the bonding means, a heat pressurization process is required, and the panel, due to residual stress due to the difference in temperature and the coefficient of thermal expansion when the panel, the COF and the bonding means are connected, Stress concentration occurs at the interface between the adhesive and the adhesive means, and at the interface between the COF and the adhesive means.

Therefore, in terms of the base resin, a material design that lowers the elastic modulus of the bonding means and imparts stress relaxation characteristics to alleviate stress concentration is required.

If the elastic modulus of the material is arbitrarily lowered to relieve the stress, it may cause a problem that the connection resistance increases due to the drop in adhesion. In particular, the rapid increase in the connection resistance after aging compared to the initial stage can be seen in the low elastic modulus COF compared to the high modulus COF. Therefore, it is very important to design a material that can maintain a moderate level of elastic modulus and simultaneously control high adhesion and low connection resistance.

On the other hand, since the NCP type adhesive means maintains the connection between the bumps of the driving IC and the pads on the display array substrate only by mechanical bonding, the connection resistance increases when the NCP type adhesive means exists between the two components. It is desirable to minimize the NCP type of adhesive means between the two components as it causes a drop.

The interfacial peeling pattern is a result of the combination of various factors, and the causes for this are various. However, the main cause is based on the results of the expansion due to water absorption, such as the properties of the resin such as glass transition temperature (Tg) and adhesion. Degradation and tensile stress, stress migration, ion migration due to corrosion (oxidation) due to moisture infiltration, and compressive stress due to pressurization have become.

The most important factor is known as residual stress of NCP type bonding means after COF bonding.

The main factors that determine peeling between electrodes in contact with each other are the bonding force and the interface separation force. Conventional NCP type bonding means generates shear stress due to the difference in thermal expansion coefficient between bumps, array substrates, and driving ICs provided in the driving IC after cooling, resulting in residual stress between interfaces. There is a problem that the physical connection between the electrodes is destroyed and the connection resistance is increased, and the separation between the NCP type adhesive means and the electrode occurs, so that reliability is not secured.

The present invention effectively adds a small amount of conductive particles to simultaneously solve the problem that the currentity and fairness are trade-off, thereby ensuring fairness and currentity, and effectively causing a problem of peeling between the PI film and the driving IC. An NCP type adhesive means that can be suppressed and a display device having the same are proposed.

NCP-type adhesive means according to an embodiment of the present invention includes a hydrophobic property to effectively control the peeling problem between the PI film and the drive IC due to the stress concentration and adhesion loss on the drive-IC edge region by including an appropriate amount of coupling agent Polyester acrylic, consisting of a bulky side group with stress relief, an ester functional group that imparts adhesion, and an acrylate or methacrylate base capable of thermal and light curing Polyester acrylate or polyester methacrylate is introduced, and the level of stable flatness without mechanically increased radius of curvature is reduced by about 20% compared to the initial length of the driver IC. Through this, it is possible to cope with NB and fine pitch of large area curved TV. In a low-temperature fast curing, high adhesion, endothelial, and provides NCP type adhesive means for securing low stress COF.

Hereinafter, the composition of the NCP type adhesive means used for bonding the COF and the display panel according to an embodiment of the present invention.

The NCP type adhesive means according to the embodiment of the present invention includes a resin that is largely based, any one of a coupling agent or an adhesion enhancer, or both a coupling agent and an adhesion enhancer, and also comprises an appropriate amount of conductive particles. Is characteristic.

The NCP type adhesion means having such a configuration may further comprise an ionic curing agent and a photo curing accelerator in addition to the resin serving as the base, a coupling agent or / and an adhesion improving agent, and an appropriate amount of conductive particles.

At this time, the coupling agent is 1 to 3% by weight (more preferably 2 to 3% by weight) based on the total content of the NCP type adhesive means, the adhesion improving agent is 3 to 3 based on the total content of the NCP type adhesive means 9 wt% (more preferably 6 to 9 wt%), the conductive particles are preferably 0.01 to 4.0 wt% (more preferably 0.01 to 0.5 wt%).

And, when the NCP type adhesion means further comprises an resin serving as the base, a coupling agent or / and an adhesion enhancer, and an ionic curing agent and a photocuring accelerator in addition to the conductive particles, the ionic curing agent and the photocuring accelerator It is preferable to be more than 0.01 and less than 10% by weight (preferably 1 to 5% by weight) based on the total content of the NCP type adhesive means, respectively.

The most characteristic of the NCP type adhesive means according to an embodiment of the present invention having such a composition and composition ratio is that the coupling agent or / and the adhesion enhancer and the conductive particles are contained in an appropriate amount.

On the other hand, it is preferable that the base resin which is one of the constituent materials of the NCP type bonding means according to the embodiment of the present invention having such a configuration is an epoxy resin or an acrylate resin.

In this case, the epoxy resin may be at least one selected from the group consisting of naphthalene-based epoxy monomers, epoxy acrylate monomers, BPA-based epoxy monomers, BPF-based epoxy monomers, cresol-based epoxy monomers and noblock-based epoxy monomers.

In addition, the acrylate-based resin is 2-ethylhexyl acrylate, trilydecyl methacrylate, nonylphenol ethoxylate monoacrylate, beta carboxy ethyl acrylate, isobornyl acrylate, tetrahydrofurfuryl acrylate, tetrahydro In the group consisting of loperfuryl methacrylate, 4-butylcyclohexyl acrylate, dicyclopentenyl acrylate, dicyclopentenyl oxyethyl acrylate, ethoxy ethyl acrylate, ethoxylated monoacrylate It may be one or more materials selected.

In addition, the coupling agent is a material that forms a COF, PI, an array substrate of the panel itself or a material forming a pad portion, for example, a transparent conductive material, such as indium tin oxide (ITO) or indium zinc oxide (IZO) Since the adhesive force with () should be excellent, it is contained in order to improve the adhesive force at the interface with the material which forms these COF, and the material which comprises an array substrate.

Such coupling agents include amphiphilic substances at the interface between the array substrate and the COF, such as 3-Aminopropyl diisopropyl ethoxysilane, 3-Glycidoxypropyl diisopropyl ethoxysilane, 3-Cyanopropyldiisopropylchlorosilane, n-octyl diisopropyl chloro silane, N-methyl-3-amino It may be any one of propyltrimethoxysilane and N, N-dimethyl-N-octadecyl-3 aminopropyltrimethoxysilylchloride (DMOAP).

In addition, the adhesion improving agent may improve the adhesive force by participating in the crosslinking reaction with the base resin to improve the adhesive force, such as a polyester compound, for example, polyester acrylate (polyester acrylate), polyester It may be one of methacrylate (polyester methacrylate), polyester epoxy (polyester epoxy).

Such an adhesion improving agent is characterized in that it serves to impart hydrophobic properties to the NCP type adhesive means in addition to the adhesive force increase. This is because the ester compound itself is characterized by reducing the moisture absorption rate.

Thus, when the adhesion improving agent is provided in the NCP type adhesive means, it has hydrophobic properties, and the hydrophobic property can suppress moisture penetration into the interface between the COF and the array substrate, thereby enhancing the expansion force between the COF and the array substrate. The gap is generated on the contact surface, which has the effect of reducing the occurrence of contact failure.

Furthermore, as one component of the polyester compound, an ester functional group serves to enhance adhesion to the polyimide film, and the bulky side group of the base resin is stress releasing. The chemical structure design is reflected to have a function.

It is preferable that the said electroconductive particle is silver nanoparticle.

Table 1 shows the dispersibility, viscosity, and curing of the NCP type adhesive means including the coupling agent and / or the adhesion improving agent while changing the content ratio of each of the coupling agent and the adhesive improving agent. The result of measuring the rate connection resistance and adhesive force is shown.

In this case, the NCP type adhesion means is measured for containing N-methyl-3-amino propyltrimethoxysilane as the coupling agent and polyester acrylate as the adhesion improving agent.

In Table 1, when the content of the adhesion enhancer without the coupling agent is 3% by weight, 6% by weight, 9% by weight are described as Example 1, Example 2 and Example 3, respectively, the adhesion enhancer without the coupling agent It is described as Comparative Example 1 that the content of 12% by weight.

In addition, in Table 1, in the case where the content of the adhesion improving agent is 6% by weight, the content of the coupling agent is 1% by weight, 2% by weight, 3% by weight in Examples 4, 5 and 5, respectively. It was described as 6, and the content of the coupling agent 4% by weight was described in Comparative Example 2.

In Table 1, spec is the minimum required value of each measurement item.

Among the measurement items, TAT represents the time taken to cure to the reference curing rate at 120 ° C., and CTE represents the expansion rate according to the temperature change. In addition, the driving reliability is a measure of the occurrence of line dim defects in the display area when driving for 500 hours in a 60 ° C, 90% temperature and humidity atmosphere. It is described as 'NG'.

Looking at Examples 1 to 3 and Comparative Example 1, characterized in that only the content ratio of the adhesion improver without a coupling agent, it can be seen that the content of the polyester acrylate, which is the adhesion improver, is maximized at 6% by weight.

That is, despite the increase in the content of the adhesion improver, the adhesion is not improved, the content ratio is the highest point based on the 6% by weight, it can be seen that the adhesive strength is gradually reduced even if the content ratio increases.

At this time, it can be seen that in Examples 1 to 3 and Comparative Example 1, the adhesive force is 80 Kgf / cm 2 or more, which greatly exceeds the reference value of 30 Kgf / cm 2 in terms of adhesive force.

The initial / aging (1,000 hours) peel strength, which can ultimately determine the proper use of NCP type adhesive means for COF, was selected as the property of 1000/900 gf / cm specification. Reliability can be secured.

However, when the adhesion enhancer is contained in an amount exceeding 9% by weight, the viscosity is greatly increased to exceed the reference value of 10000 ± 1500 cP, and further, the curing time (TAT), which is a product manufacturing productivity aspect, is 6 seconds as a reference value. (sec) is exceeded, so the specification is out.

On the other hand, although not shown in Table 1, when the content of the adhesion improver is less than 3% by weight, the adhesive force does not tend to increase significantly.

Therefore, the appropriate content of the adhesion improver in the NCP type adhesion means is 3 to 9% by weight, more preferably 6 to 9% by weight of the aging peel adhesion properties greater than 900gf / cm is appropriate. Able to know.

division unit Spec Example 1 Example 2 Example 3 Comparative Example 1 Example 4 Example 5 Example 6 Comparative Example 2 polyester acrylate weight% - 3.0 6.0 9.0 12.0 6.0 6.0 6.0 6.0 N-methyl-3-Aminopropyl trimethoxy silane weight% - 0.0 0.0 0.0 0.0 1.0 2.0 3.0 4.0 Dispersibility - Good Good Good Good Good Good Good Good Good Viscosity (@RT) cP 10,000 ± 1,500 9,850 10,500 11,300 12,100 10,960 10,250 9,800 10,850 TAT (@ 120 ℃) sec <6 5 5 6 7 5 5 5 5 Curing rate (%) % > 80 93 93 89 86 93 93 92 92 CTE (α1) Ppm / ℃ <70 43 43 44 44 43 43 43 43

God

Lightning

castle Connection resistance mΩ <1.50 1.21 1.22 1.22 1.23 1.22 1.22 1.22 1.22 Die shear
Adhesion Kgf / ㎠ > 30 81 88 85 84 89 90 92 87 Peel strength
(Early) gf / cm > 1,000 1,120 1,260 1,200 1,080 1,290 1,325 1,380 1,260 Peel strength
(1000 hours aging) gf / cm > 900 940 1,010 980 860 1,030 1,050 1,110 1,000 Driving reliability - pass pass pass pass Pass pass pass pass Pass

On the other hand, the experiment according to Examples 4 to 6 and Comparative Example 2 was carried out to calculate the optimal concentration of the coupling agent content for reinforcing the adhesive strength with the PI and glass substrate based on the content ratio of Example 2.

According to Table 1, when the content of the coupling agent in the NCP type adhesive means to increase the content of the coupling agent up to 3% by weight gradually increases the adhesive force, it can be seen that the adhesion is sharply reduced when added to a content greater than 3% by weight.

Therefore, it can be seen that the content of the coupling agent is preferably 1 to 3% by weight.

Although the coupling agent is not spec out in the measurement item even if the content is substantially 4% by weight, the coupling agent has a maximum content ratio of 3% by weight and has a content ratio higher than this, so that it has an interface saturation or higher. At concentrations (e.g., critical micelle concentrations (CMCs), they exist as dispersed phases, rather degrading adhesion, and do not improve the properties of other metrics, so the amount is equal when realizing the same material cost). It is preferable to lower the content ratio of the coupling agent is 1 to 3% by weight is preferable.

Table 2 shows the results of measuring the dispersibility, viscosity, curing rate connection resistance and adhesion while changing the content ratio of the conductive particles in the NCP type adhesive means according to the embodiment of the present invention including the conductive particles. In this case, the conductive particles are silver nanoparticles, and the measurement items are the same as the items listed in Table 1 except for the insulation resistance, and thus description of the same measurement items as in Table 1 is omitted.

Insulation resistance represents the insulating property of the material, the larger the value is higher the insulating property, if the value is less than 10 ⁹ mΩ and the conductive properties are increased to act as a wiring.

division unit Spec Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Comparative Example 3 polyester acrylate weight% - 6.0 6.0 6.0 6.0 6.0 6.0 6.0 N-methyl-3-Aminopropyl trimethoxy silane weight% - 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Silver Nano Particle Content wt.% - 0.1 0.2 0.5 1.0 2.0 4.0 5.0 Dispersibility - Good Good Good Good Good Good Good Good Viscosity (@RT) cP 10,000 ± 1,500 9,850 9,970 11,500 13,500 14,200 17,450 19,400 TAT (@ 120 ℃) sec <6 5 5 5 6 7 8 9 Curing rate (%) % > 80 92 92 90 87 85 82 79 CTE (α1) ppm / ℃ <70 42 41 41 39 38 36 35

God

Lightning

castle Connection resistance mΩ <1.50 1.25 1.22 1.20 1.18 1.18 1.15 1.12 Insulation Resistance mΩ > 10 ^9-12 10 ¹² 10 ¹² 10 ¹² 10 ¹¹ 10 ¹⁰ 10 ⁹ 10 ⁸ * Die shear
Adhesion Kgf / cm2 > 30 34 35 38 41 41 44 45 Peel strength
(Early) gf / cm > 1,000 1,380 1,375 1,350 1,300 1,180 1,100 1,010 Peel strength
(1000 hours aging) gf / cm > 900 1,100 1,100 1,070 1,040 940 880 850 Operational Reliability * - pass pass pass pass pass pass pass NG (short)

Referring to Table 2, the increase in the content of silver nanoparticles serves to effectively disperse the stress concentrated at the interface by effectively reducing the CTE, the volume expansion rate with temperature changes, through the increase of the surface area and uniformity of the silver nanoparticles. Able to know.

On the other hand, referring to Examples 7,8,9, it can be seen that at the level of the content of silver nanoparticles less than 1.0% by weight, it satisfies the minimum requirements for TAT, viscosity, curing rate, expansion rate, and connection resistance. have.

On the other hand, in Examples 10, 11, 12 and Comparative Example 3 in which the content of the silver nanoparticles is 1.0% or more, it can be seen that the viscosity and the TAT increase rapidly. Furthermore, in the case of Comparative Example 3 in which the silver nanoparticles had a content of 5% by weight, it can be seen that a short was generated.

Based on the results according to Table 2, it was found that the content of the silver nanoparticles in the NCP type adhesion means preferably has a content ratio of less than 0.1 to 4% by weight that no short occurs.

On the other hand, theoretically, based on the effective volume of the drive IC that is discharged from the upper and lower electrode portions by the pressurization of the NCP type adhesive means and filled in the empty space, the silver nanoparticles may form a bridge continuously to cause a short circuit. By inferring the possibility, it is possible to calculate the content ratio of silver nanoparticles that should be included to the minimum.

If the silver nanoparticles content is more than 1.0% by weight, the shear bond strength tends to increase due to the increase of elastic modulus and viscosity of the material and local aggregation, but the peel strength, which is the most important characteristic for bonding with COF, Fell.

Therefore, when the silver nanoparticles are larger than 0.5% by weight, since the desired viscosity reference range is exceeded, it can be seen that the silver nanoparticles have a content ratio of 0.1 to 0.5% by weight.

On the other hand, in the NCP type adhesive means according to an embodiment of the present invention having the above-described configuration, in addition to the resin as the base, the coupling agent or / and the adhesion improving agent and the appropriate amount of conductive particles, further ionic curing agent and light curing accelerator It may be configured to include.

In this case, it is preferable that the ionic curing agent and the light curing accelerator have a content ratio of more than 0.01 and less than 10% by weight, respectively, based on the total content of the NCP type adhesive means.

On the other hand, the ionic curing agent may be a boric acid salt (Borate) or iodine (Iodine) salt.

The photo cure accelerator is configured to make curing of the base resin easier and faster during UV light irradiation. For example, the photo cure accelerator is a light diffusion polymer material having a light diffusing function, such as polystyrene (PS), polycarbonate (PC), and polyethylene. Terephthalate (PET).

In this case, the light-diffusion polymer material may be in the form of particles, the light-diffusing particles are characterized in that the refractive index has a value larger than the base resin, and further preferably has a refractive index of 1.5 or more. The light diffusing particles having such a high refractive index may have a spherical or amorphous form.

The NCP type adhesion means further comprises an ionic curing agent and a photocuring accelerator, together with a coupling agent or / and an adhesion enhancer and conductive particles, is characterized in that it is cured in response to UV light, and the photocuring accelerator is included to irradiate UV light. Even when the structure that shields the UV light is disposed at a point in time at which the light is emitted, a region where direct UV light is not irradiated is generated, so that light diffusion occurs inside the UV light to a region where the UV light is not directly irradiated by the shielding structure. It has been found that the curing rate is improved by having the function of reaching the light.

And, in addition to the base resin and the hydrophobicity improver NCP-type adhesive means further comprises a ionic curing agent and a photo-curing accelerator has a thermal curing characteristics, so that the shield is selectively provided to the area where the UV light is not irradiated, In addition to the irradiation of the phase UV light has a merit that can be cured a little more stable by further proceeding the heat curing step of applying a heat in a contact manner using a heating bar as in the prior art.

In this case, the thermosetting process is not heated so that the temperature reached to the NCP type bonding means is 150 to 190 ℃ by using the conventional heating bar, but to a temperature of 110 to 130 ℃ lower than the above-mentioned temperature Even if it is a feature that can be cured sufficiently.

On the other hand, since the NCP type adhesive means according to the embodiment of the present invention does not have a plurality of conductive balls therein as in the conventional ACF, the width and the spacing interval of the wiring provided in the panel or the COF are narrowed. When agglomeration of conductive balls occurs, short-circuit defects can be prevented from occurring between neighboring wirings, and the NCP includes conductive particles in the form of nano-level particles that are relatively smaller in size than the plurality of conductive balls. It has the effect of improving the electrical conductivity of the adhesive means of the type.

Hereinafter, a method of bonding the panel and the COF using the NCP type adhesive means according to an embodiment of the present invention will be described briefly.

2a and 2b is a view showing bonding the panel and the COF using the NCP type bonding means according to an embodiment of the present invention.

As shown in FIG. 2A, the panel 110 in which the array substrate 107 and the counter substrate 105 are bonded to each other is placed on the base 200, and the array substrate 107 of the panel 110 is positioned. The NCP type adhesive means 120 according to the embodiment of the present invention is grapeed through a dispenser or the like, corresponding to an area in which the gate and the data pad electrode (not shown) are provided.

In this case, the NCP type adhesive means 120 has a uniform thickness and well formed by satisfying the reference value as both viscosity and dispersibility as described through Table 1.

In this state, one end of the COF 130 is placed on the array substrate 107 of the panel 10 to overlap with the NCP type bonding means 150 on the top of the NCP type bonding means 150. In contact with the NCP type adhesive means 150. In this case, the COF 130 has a double layer structure consisting of two FPCs (130a, 130b) made of a PI material, each of the FPC (130a, 130b) is provided with a copper wiring (not shown), the double layer The driver IC 133 is provided in any one of the FPCs 130a of the FPCs 130a and 130b having the structure.

Next, as shown in FIG. 2B and FIG. 2C, the COF 130 is in contact with the NCP type bonding means 120 applied on the array substrate 107. The heating bar is placed on the top of the COF 130 and the thermal pressurizing means 150 is in contact with the shock absorbing means 140 in a state where the shock absorbing means 140 is disposed on the surface of the COF 130. 130 is thermally pressurized.

In this case, as illustrated in FIG. 2D, the COF 130 has a gate or data pad electrode (not shown) provided with a plurality of wires or electrodes (not shown) provided therein in the array substrate 107. And the NCP type adhesive means 120 are wrapped around the electrode (not shown) and the wiring (not shown) provided in the pad electrode and the COF 130, respectively.

In this state, as shown in FIG. 2E, when the thermal pressurization means (150 of FIG. 2D) and the buffer means (140 of FIG. 2D) are removed from the upper portion of the COF 130, the heat supply is not performed. The NCP type adhesive means 120 is hardened to fix the COF 130 on the panel 110.

In this case, the NCP type adhesive means 120 according to the embodiment of the present invention includes silver nanoparticles (not shown) as conductive particles having a size of a nanometer level therein, such silver nanoparticles (not shown) Insulation property is maintained between adjacent wirings (not shown) or between pad electrodes (not shown) by the role of the electrical conductance between the wiring (not shown) of the COF 130 and the pad electrode (not shown) of the panel 110. Will improve.

Furthermore, the NCP type adhesive means 120 according to the embodiment of the present invention enhances the adhesive strength of the panel and the COF 130 as compared to the conventional ACF by including an appropriate amount of a coupling agent or / and an adhesive enhancer.

Therefore, the NCP type bonding means 120 according to the above-described embodiment of the present invention is provided in a curved display device (not shown) having a large area so that the COF 130 may be mounted. It is possible to suppress the occurrence of peeling, and furthermore, even if the bonding portion is narrowed by the radius of curvature of the curved display device (not shown), the peeling of the COF 130 can be suppressed because the adhesive force per unit area is larger than that of the conventional ACF. .

On the other hand, in the above-described method of mounting the COF 130 according to the embodiment of the present invention is shown as an example proceeds through a heat press process, Figure 3 (on the display device panel according to a modification of the embodiment of the present invention) As shown in the drawing showing a part of the step of mounting the COF 130), the NCP type adhesive means 120 is a suitable content ratio of ionic curing agent in addition to the base resin and the coupling agent or / and the adhesion enhancer and the conductive particles And a photo-curing accelerator, the UV light is emitted using the UV irradiation apparatus 310 simultaneously with the heat pressurization using the heat pressurizing means 150 or before the heat pressurization is carried out. By irradiating the NCP type adhesive means 120 through the hardening of the NCP type adhesive means 120 can proceed.

When UV light is further irradiated in addition to the thermal pressurization using the thermal pressurization device as described above, since the temperature of the thermal pressurization means can be proceeded at a low temperature of 20 to 80 ° C., the mounting of the COF 130 can be performed in a relatively low temperature process. Is characteristic.

In this case, problems such as deformation of the polarizing plate and the like, deformation of the COF 130 itself, and mounting position of the COF 130 may be suppressed due to the progress of the high temperature process.

Meanwhile, referring to FIGS. 2A through 2E, the bonding between the COF 130 and the panel 110 of the display device is described using the proposed NCP type bonding means 120 as an example. It is apparent that the proposed NCP type adhesive means 120 including a coupling agent or / and an adhesive enhancer and conductive particles may be a bonding between the panel 110 and TCP in place of the COF 130. The invention is not limited to the above embodiments, and various changes and modifications may be made without departing from the spirit of the invention.

107: array substrate
105: counter substrate
110: panel
120: NCP type bonding means
130: COF
130a, 130b: (COF) FPC
133: Drive IC
140: buffer means
150: thermal pressurization means
200: water bed

Claims

A panel on which the array substrate and the opposing substrate are bonded;
Is formed on the pad provided in the non-display area of the array substrate,
A resin serving as a base; A coupling agent having compatibility with the surface of the panel and the surface of a chip on film (COF); An adhesion improving agent having a hydrophobicity and a material capable of improving adhesion by participating in a crosslinking reaction with the resin; A non-conductive paste (NCP) containing conductive particles;
It comprises a chip on film (COF) mounted in contact with the non-conductive paste (NCP, non-conductive paste),
Curved display device having a constant radius of curvature and configured in a curved shape.

The method of claim 1,
The coupling agent has a content of 1 to 3% by weight based on the total content of the non-conductive paste (NCP),
The adhesion improving agent is 3 to 9% by weight based on the total content of the non-conductive paste (NCP, non-conductive paste),
The conductive particles are curved display device characterized in that the content of 0.1 to 4.0% by weight based on the total content of the non-conductive paste (NCP, non-conductive paste).

The method of claim 2,
The coupling agent,
One of 3-Aminopropyl diisopropyl ethoxysilane, 3-Glycidoxypropyldiisopropyl ethoxysilane, 3-Cyanopropyldiisopropylchlorosilane, n-octyldiisopropyl chlorosilane, N-methyl-3-amino propyltrimethoxysilane, N, N-dimethyl-N-octadecyl-3-aminopropyltrimethoxysilylchloride (DMOAP) Characterized curved display.

The method of claim 2,
The adhesion enhancer,
Curved display device characterized in that the polyester compound.

The method of claim 4, wherein
The polyester compound is a curved display device, characterized in that any one of polyester acrylate (polyester acrylate), polyester methacrylate (polyester methacrylate), polyester epoxy (polyester epoxy).

The method of claim 1,
The resin is an epoxy resin or an acrylate resin,
The epoxy resin is at least one material selected from the group consisting of naphthalene-based epoxy monomers, epoxy acrylate monomers, BPA-based epoxy monomers, BPF-based epoxy monomers, cresol-based epoxy monomers and novolac-based epoxy monomers,
The acrylate-based resin is 2-ethylhexyl acrylate, tridecyl methacrylate, nonylphenol ethoxylate monoacrylate, beta-carboxyethyl acrylate, isobornyl acrylate, tetrahydroperfuryl acrylate, tetra hydroper Selected from the group consisting of furyl methacrylate, 4-butylcyclohexyl acrylate, dicyclopentenyl acrylate, dicyclopentenyl oxyethyl acrylate, ethoxyethyl acrylate, ethoxylated monoacrylate Curved display device characterized by at least one material.

The method of claim 1,
The non-conductive paste (NCP, non-conductive paste) further comprises an ionic curing agent and a photo cure accelerator, characterized in that the cured display device characterized in that it cures in response to UV light.

The method of claim 7, wherein
And the ionic curing agent and the photocuring accelerator are each greater than 0.01 and less than 10 wt% based on the total content of the non-conductive paste (NCP).

The method of claim 8,
The ionic curing agent is a boric acid salt (Borate) or iodine (Iodine) salt,
The light curing accelerator is a light diffusion polymer material having a light diffusing function, characterized in that any one of polystyrene (PS), polycarbonate (PC), polyethylene terephthalate (PET).

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