JP3277765B2 - Manufacturing method of liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal driving substrate on which a TFT element is formed, and a counter substrate provided with a light sensitivity improving measure such as a color filter or a microlens. The present invention relates to a method for manufacturing a liquid crystal display device by forming a liquid crystal panel member, performing liquid crystal injection and external connection wiring.

[0002]

2. Description of the Related Art Conventionally, in manufacturing a liquid crystal display device,
A borosilicate glass or quartz glass substrate on which a driving element such as a TFT element is formed and a borosilicate glass or quartz glass substrate on which a color filter is formed are superimposed,
This is divided to form individual liquid crystal panel members.
Also, after injecting a predetermined liquid crystal into the formed liquid crystal panel member, a flexible printed wiring board is connected to the electrode pads of the liquid crystal panel member by thermocompression bonding, and a polarizing film is attached to the front and back of the liquid crystal panel member. It is trying to make it.

[0003]

When the flexible printed wiring board is thermocompression-bonded, a predetermined anisotropic conductive adhesive is used to secure predetermined electric conduction characteristics and mechanical adhesive strength. Although the connection is made by heating and pressurizing, it is very important to precisely control the heating and pressurizing. In other words, if the heating temperature is too high, a large amount of heat is transmitted to the connection parts such as the electrode pads and the surrounding area, and the damage due to the heat causes chipping or cracking of the TFT-side substrate, deterioration of TFT element characteristics, deterioration of the sealant, color filter side. On the substrate, there is a problem that the color of the color filter is changed, and the quality of the injected liquid crystal is deteriorated due to the deterioration of the injected liquid crystal.

On the other hand, if the heating temperature is too low, the insulating material comprising a thermosetting or thermoplastic binder in the anisotropic conductive adhesive does not sufficiently soften, and the conductive fine particles in the anisotropic conductive adhesive are crushed. Insufficiently, the desired electrical and mechanical connection characteristics cannot be obtained.

[0005] Further, if the pressure is too large, chipping or cracking of the TFT side substrate may occur. If the pressure is too small, the conductive fine particles in the anisotropic conductive adhesive may be crushed as in the case of the low heating. Is insufficient, so that accurate electrical conduction and sufficient mechanical strength cannot be obtained.

In the conventional method of manufacturing a liquid crystal display device, a liquid crystal panel member is formed by dividing a superposed TFT side substrate and a color filter side substrate, and then liquid crystal injection and thermocompression bonding of a flexible printed wiring board are performed. When doing it,
Extra liquid crystal, dust, scratches, etc. are likely to adhere to the surface of the TFT-side substrate or the color filter-side substrate. Furthermore, since the liquid crystal is sealed with an ultraviolet irradiation-curable adhesive, the vicinity of the injection port is contaminated with the adhesive, and a sufficient cleaning operation is required to remove the adhesive, thereby lowering productivity. I have.

[0007]

SUMMARY OF THE INVENTION The present invention is a method for manufacturing a liquid crystal display device which has been made to solve such problems. That is, according to the present invention, first, the liquid crystal driving substrate and the opposing substrate are overlapped, and then the protective tape is applied to the superposed liquid crystal driving substrate and the opposing substrate. Next, after a cut groove that is not completely cut is formed in the liquid crystal driving substrate and the opposing substrate via the protective tape, the liquid crystal panel is divided into individual liquid crystal panel members by breaking. Then, the liquid crystal display device is manufactured by injecting liquid crystal and connecting a predetermined wiring member to the liquid crystal panel member with the protective tape adhered.

Further, as a protective tape used at this time,
When using a material having an ultraviolet irradiation curing type adhesive layer mixed with a conductive surfactant or connecting a predetermined wiring member to a liquid crystal panel member, the liquid crystal driving substrate and the counter substrate are connected via a protective tape. After cooling the liquid crystal, curing the protective tape with ultraviolet irradiation, and performing a predetermined heat treatment on the liquid crystal injected into the liquid crystal panel member, or protecting the liquid crystal panel member after injecting the liquid crystal and connecting a predetermined wiring member. There is also a method of manufacturing a liquid crystal display device by peeling off a tape and attaching a polarizing film via a layer of a conductive surfactant remaining on a liquid crystal driving substrate and a counter substrate.

According to such a method of manufacturing a liquid crystal display device, a liquid crystal panel substrate is formed by dividing a liquid crystal driving substrate and a counter substrate which are superimposed, and the liquid crystal is integrated and a predetermined wiring member is connected. A state in which the protective tape is attached to the surfaces of the liquid crystal drive substrate and the opposing substrate can be prevented from attaching dust and scratches during the manufacturing process.

Further, by using a protective tape having an ultraviolet irradiation-curable adhesive layer mixed with a conductive surfactant, the protective tape can be easily peeled off after the ultraviolet irradiation has been cured, and the protective tape can be peeled off. Later, a thin film of the conductive surfactant remains on the surfaces of the liquid crystal driving substrate and the opposing substrate, and the accumulation of static electricity during the manufacturing process can be prevented. Furthermore, if a thin film of the conductive surfactant remaining on the surface of each substrate when the protective tape is peeled off is used, the static electricity generated when the polarizing film is adhered or the protective tape attached to the polarizing film is peeled off. You can prevent damage.

[0011] Also, since the protective tape is attached,
When connecting a predetermined wiring member, even if the jig for cooling the liquid crystal drive substrate and the opposing substrate is brought into contact with the protective tape via this protective tape, the surface of each substrate is not damaged, and an effective By cooling, the conditions for thermocompression bonding of the wiring member can be relaxed and the area of the electrode pad can be reduced.

In addition, the heat resistance of the UV-curable adhesive cured by UV-curing the protective tape is improved, and the protective tape is damaged even when a predetermined heat treatment is applied to the liquid crystal injected into the liquid crystal panel member. Can be prevented,
The role of the protective tape can be maintained up to the step immediately before bonding the polarizing film.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method for manufacturing a liquid crystal display device according to the present invention will be described below with reference to the drawings.
1 to 5 are schematic cross-sectional views sequentially illustrating a method for manufacturing a liquid crystal display device of the present invention. First, as shown in FIG. 1A, a TFT 1 serving as a driving element is placed on a glass substrate 11 made of quartz.
2 to form a TFT-side substrate 10 as a liquid crystal driving substrate, and as shown in FIG. 1B, a predetermined color filter 22 is formed on a quartz glass substrate 21 to form a color as a counter substrate. The filter-side substrate 20 is configured.

An alignment film 12a of polyimide or the like is formed on the TFT-side substrate 10 and subjected to a rubbing process, and the common electrode 12b is printed. Further, an alignment film 22a of polyimide or the like is formed on the color filter side substrate 20 and subjected to a rubbing process, and a sealant including a liquid crystal sealant 22b and an outer peripheral sealant 22c is printed.

Next, as shown in FIG. 1C, the TFT substrate 10 and the color filter substrate 20 are superposed. The superposition is performed in a state where the TFT 12 and the color filter 22 face each other via the liquid crystal sealing agent 22b and the outer peripheral sealing agent 22c provided on the color filter side substrate 20.

Next, as shown in FIG. 2A, in this embodiment, a protective tape 50 is applied to each of the glass substrates 11 and 21 of the TFT side substrate 10 and the color filter side substrate 20. Performs the first dicing through. As the protective tape 50, for example, a tape in which an acrylic ultraviolet irradiation-curable adhesive layer mixed with a conductive surfactant is provided on a vinyl chloride or polyolefin-based substrate is used. Thereby, protection of the glass substrate in a later process,
When the protective tape 50 is peeled off, some glue residue is generated to facilitate the bonding of the polarizing films, and to prevent the accumulation of static electricity during and after manufacturing.

In the first dicing, a semi-full cut is performed by using a blade 40 so as to leave the glass substrate 11 of the TFT-side substrate 10 at about 50 to 100 μm. At this time, since the protective tape 50 is attached, chips and cutting water when performing the semi-full cut do not adhere to the surface of the glass substrate 11.

After dicing the TFT substrate 10, a second dicing process is performed on the color filter substrate 20, as shown in FIG. 2B. In this case,
The TFT substrate 10 and the color filter substrate 20 shown in FIG.
The glass substrate 21 is diced through the protective tape 50 attached to the color filter-side substrate 20 with 0 as the upper side.

In the second dicing, similarly to the first dicing, the glass substrate 2 is
A semi-full cut is performed so that 1 remains about 50 to 100 μm. Since the protection tape 50 is also attached to the color filter side substrate 20, chips and cutting water at the time of the second dicing do not adhere to the surface of the glass substrate 21.

Next, for example, 20
After irradiating ultraviolet rays of about 0 mJ / cm ² to cure the adhesive layer, braking using a roller 60 as shown in FIG. 2C is performed. Thereby, each glass substrate 11, 2
1 is in a state of being divided at the semi-full cut portion.
Then, as shown in FIG. 3A, the liquid crystal panel member 7 as shown in FIG.
Pick up 0.

The liquid crystal panel member 70 is provided with an electrode pad 13 for giving a predetermined signal to the TFT 12 formed on the TFT-side substrate 10. Further, even in the picked-up state, the protective tape 50 is still adhered to the surface of each of the glass substrates 11 and 21, and even if a suction jig (not shown) or the like at the time of picking up comes in contact with the glass substrate 11 or 21. , 21 are not scratched.

Next, as shown in FIG. 4A, a process for connecting a flexible printed wiring board (hereinafter, simply referred to as FPC) to the electrode pads 13 of the liquid crystal panel member 70 is performed. In order to connect the FPC 14 to the electrode pad 13, the crimp terminal 71 is pressed via the color filter 22 or a silicone sheet 72 for heat shielding to the sealant while the FPC 14 is arranged on the electrode pad 13, and heated and pressurized. I do. At this time, although it depends on the type of the FPC 14, the actual thermocompression bonding conditions include an effective heating of 180 to 200 ° C.,
Heating and pressurizing at 10 to ²⁰ kg / cm ² for 0 to 15 seconds.

In this embodiment, the glass substrates 11 and 21 are cooled via the protective tape 50 together with the heating and pressing. In the example shown in FIG. 4A, the liquid crystal panel member 70 is sandwiched by using a water cooling jig 51 that performs cooling with cooling water, and the glass substrates 11 and 21 are cooled via the protective tape 50. This prevents the TFT 12 provided on the glass substrate 11, the color filter 22 provided on the glass substrate 21, and the sealant from being heated and deteriorated by the heat from the crimping terminal 71, and prevents the TFT 12 from being deteriorated when the FPC 14 is connected. Thermal constraints can be relaxed.

That is, in this embodiment, each glass substrate 1
Since the protective tape 50 is adhered to the first and second substrates 21 and 21, even if the water cooling jig 51 is brought into contact, the surface thereof is not damaged.
FPC14 without considering thermal measures for 1,21
The optimal heating conditions for connecting can be set. Thus, the FPC 14 can be reliably connected without deteriorating the TFT 12 and the color filter 22.

In FIG. 4B, the heat pipe 53
2 shows an example of using a cooling jig 52 in which is incorporated.
The cooling jig 52 holds the liquid crystal panel member 70 to cool the glass substrates 11 and 21. Even in this case, since the cooling jig 52 is brought into contact with the protection tape 50, the glass substrates 11, 21 can be prevented from being damaged.
Since the heat pipe has a simple structure, it is possible to perform cooling efficiently with a small size.

FIG. 5A shows an example of performing cooling using the Peltier element 54. In this example, the Peltier element 54
The glass substrates 11 and 21 are cooled by sandwiching the liquid crystal panel member 70 and passing a predetermined current. Since the Peltier device 54 is also in contact with the respective glass substrates 11 and 21 via the protective tape 50 as in the previous example, it is possible to perform cooling without damaging the respective glass substrates 11 and 21. .

Conventionally, the area of the electrode pad 13 has been increased as much as possible in order to reduce the transmission of heat during the thermocompression bonding of the FPC 14 to each of the glass substrates 11 and 21. Since the heat at the time of thermocompression bonding of the FPC 14 can be reduced from being transmitted to the glass substrates 11 and 21, the area of the electrode pad 13 can be reduced. That is, the size of the entire liquid crystal display device can be reduced by performing various types of cooling.

Next, a liquid crystal is injected between the glass substrates 11 and 21 of the liquid crystal panel member 70, and a heat treatment (about 110 ° C., 30 minutes) for obtaining the orientation is performed. When the liquid crystal is injected or the liquid crystal injection port is sealed with an adhesive, since the protective tape 50 is adhered to the surface of each of the glass substrates 11 and 21, the excess liquid crystal and the adhesive are directly attached. I will not do it. That is, it is not necessary to perform a special cleaning process after this step, and the step can be greatly simplified.

Before the above-described breaking treatment, the protective tape 50 is irradiated with ultraviolet rays to cure the adhesive layer, thereby improving the heat resistance. 50 does not change. Note that this liquid crystal injection and heat treatment step is performed as shown in FIG.
It may be performed before the connection processing of the FPC 14 shown in FIG. 5B and FIG.

Next, as shown in FIG. 5B, a process of peeling the protective tape 50 is performed. Since the conductive surfactant is mixed in the adhesive layer of the protective tape 50, the thin film 50a of the adhesive layer remains on the surfaces of the glass substrates 11 and 21 after the protective tape 50 is peeled off. Become. This thin film 50a has a thickness of about several nm and has no influence on optical characteristics.

Further, the thin film 50a has conductivity. For example, when an amphoteric surfactant is used, the resistance value is 10 ⁶ to 10 ¹² Ω / □. As a result, static electricity during and after the production is reduced by the thin film 50.
a, and can prevent electrostatic damage to the TFT element and the like.

Next, as shown in FIG. 5C, a process of bonding the polarizing films 55 to the surfaces of the respective glass substrates 11 and 21 is performed. When the protective tape 50 is peeled off in the previous step, the thin film 50a of the adhesive layer remains on the surfaces of the glass substrates 11 and 21. For this reason, static electricity generated when the polarizing film 55 is attached or the protective film is peeled off is released to the outside, and damage to the TFT element 12 can be reduced to improve the yield and quality.

In general, in order to release static electricity generated when the polarizing film 55 is bonded or the protective film is peeled off to the outside, measures such as employing a conductive adhesive as an adhesive layer of the polarizing film 55 are taken. However, in the present invention, since the conductive thin film 50a described above remains on the surfaces of the glass substrates 11 and 21, the same effect as that of the conductive adhesive described above can be exerted.
Cost can be reduced.

The polarizing film 55 is applied to each glass substrate 1
The liquid crystal display device 1 is completed by laminating the liquid crystal display devices 1 and 21. In the present embodiment, since the protective tape 50 is applied to the surface of each of the glass substrates 11 and 21 until immediately before the polarizing film 55 is attached, it is possible to prevent dust from being adhered or damaged in each step. Further, the cleaning process can be eliminated by the protective tape 50.

FIG. 6 is a schematic sectional view for explaining a state in which an outer frame is attached to the liquid crystal display device 1. That is, the outer frame 80
Is a liquid crystal display 1 via a silicone RTV 81, for example.
Attached to. For this reason, even if extra liquid crystal in the liquid crystal injection step or an ultraviolet irradiation-curable adhesive in the liquid crystal injection port sealing step adheres to the side surfaces of the glass substrates 11 and 21, the outer frame is formed via the silicone RTV 81. Once the 80 is attached, there is no need to separately clean them.

That is, according to such a series of steps, in the method of manufacturing the liquid crystal display device of the present embodiment, it is possible to completely eliminate the cleaning process in the manufacturing steps after the superposition, greatly reducing the production steps. It can be simplified.

[0037]

As described above, according to the method for manufacturing a liquid crystal display device of the present invention, the following effects can be obtained. That is, since the protective tape is adhered to the surface of each glass substrate, dust or dirt may be attached to the surface of each glass substrate during dicing division, thermocompression bonding of wiring members, liquid crystal injection, and sealing work. Can be prevented. In addition, when performing thermocompression bonding of the wiring member, cooling can be performed without damaging or dusting each glass substrate via the protective tape, which leads to deterioration of the driving element, the color filter, the liquid crystal, the sealant, and the like. Therefore, it is possible to connect the wiring members under optimum conditions.

Further, since the thermal constraint at the time of thermocompression bonding of the wiring member can be relaxed, the area of the electrode pad portion can be reduced, and the size of the entire liquid crystal display device can be reduced. In addition, since the conductive surfactant is mixed into the adhesive layer of the protective tape, a thin film of the conductive surfactant remains on the surface of each glass substrate even when the protective tape is peeled off, and the conductive tape is provided with the conductive surfactant. The thin film prevents accumulation of static electricity when the protective tape is peeled off, when the polarizing film is bonded, or when the polarizing film protective film is peeled off, and the drive element and the like can be prevented from being damaged by static electricity. Further, since the thin film is always conductive at the humidity of the outside air, it is possible to prevent electrostatic breakdown even after shipping.

Further, since the surface of each glass substrate is protected by attaching a protective tape until immediately before the lamination of the polarizing film, the washing after sealing the liquid crystal can be omitted. These make it possible to greatly simplify the manufacturing process of the liquid crystal display device and improve the operation reliability of the liquid crystal display device.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view (part 1) for sequentially explaining a method for manufacturing a liquid crystal display device.

FIG. 2 is a schematic cross-sectional view (part 2) for sequentially explaining the method for manufacturing the liquid crystal display device.

FIG. 3 is a schematic cross-sectional view (part 3) for sequentially explaining the method for manufacturing the liquid crystal display device.

FIG. 4 is a schematic cross-sectional view (part 4) for sequentially explaining the method for manufacturing the liquid crystal display device.

FIG. 5 is a schematic cross-sectional view (part 5) for sequentially explaining the method for manufacturing the liquid crystal display device.

FIG. 6 is a schematic cross-sectional view illustrating an attached state of an outer frame.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 10 TFT side substrate 11 Glass substrate 12 TFT 20 Color filter side substrate 21 Glass substrate 22 Color filter 30 Sealant 50 Protective tape 55 Polarizing film 70 Liquid crystal panel member

Claims (3)

(57) [Claims] A step of superposing a liquid crystal driving substrate and a counter substrate on each other ;
Has UV-irradiation-curable adhesive mixed with surfactant
Applying a protective tape that does not completely cut the liquid crystal driving substrate and the opposing substrate through the protective tape, and then dividing the liquid crystal panel member into individual liquid crystal panel members by breaking. A step of injecting liquid crystal and connecting a predetermined wiring member to the liquid crystal panel member with the protective tape adhered thereto, the method comprising the steps of: 2. The liquid crystal according to claim 1, wherein when connecting a predetermined wiring member to the liquid crystal panel member, the liquid crystal driving substrate and the counter substrate are cooled via the protective tape. A method for manufacturing a display device. 3. After injecting liquid crystal and connecting a predetermined wiring member to the liquid crystal panel member, the protective tape is peeled off, and the conductive surfactant remaining on the liquid crystal driving substrate and the counter substrate is removed. method of manufacturing a liquid crystal display device according to claim 1, wherein the via layers bonding the polarizing film.