JP2001054756A - Paste applying device, formation of extraction electrode and liquid crystal element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paste applying device capable of making a process efficient. SOLUTION: This coating device is provided with a paste storage part 21 for storing a paste and a paste stirring mechanism 3 having a stirring member reciprocally moving in the vertical direction while rotating in the paste storage part 21. The paste is kept constantly in a uniform dispersing state and is used in a low viscosity by stirring the paste stored in the paste storage part 21 with stirring member. Being low in viscosity, the paste is dried at an ordinary temp. in a short time and in the case of forming an extraction electrode for applying voltage to a liquid crystal element 10, the extraction electrode having excellent joining property to a transparent electrode 12A is obtained because the paste is infiltrated into an insulating film 13A to unnecessitate the removal of the insulating film 13A and the production process of the liquid crystal element is made efficient.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paste coating apparatus which discharges a paste composed of a mixture of fine particles, a binder resin and an organic solvent from a discharge head and forms an extraction electrode on a substrate arranged on a surface plate. , Extraction electrode forming method,
And two substrates with electrodes, at least one of which is transparent;
And a liquid crystal element having a liquid crystal material sandwiched between the substrates.

[0002]

2. Description of the Related Art Conventionally, as a technique for forming an extraction electrode on a substrate of a display element such as a liquid crystal element, a high-viscosity (specifically, about 10,000 cps) silver paste is applied using a dispenser such as a paste application apparatus. The technique to do is common. The reason is that if the viscosity of the paste is high, the phenomenon that the fine particles in the paste and the binder resin are separated from each other due to a difference in specific gravity in a one-day process is unlikely to occur. The paste coating device discharges a paste made of a mixture of fine particles, a binder resin, and an organic solvent from a discharge head, and forms an extraction electrode on a substrate disposed on a surface plate. When applying and applying such a paste from an ejection head, the paste is pressed and extruded to the ejection head in the ejection direction. Also, when not applying, in order to remove the paste attached to the discharge port of the discharge head, a vacuum suction mechanism for vacuum suction on the side opposite to the discharge direction, by removing the paste, This prevents the paste from drying and solidifying on the ejection head. In this case, when the binder resin is a thermoplastic resin, there is a problem that the durability is inferior in terms of adhesion to a substrate and scratch resistance. In order to solve this, a thermosetting resin is mixed in the paste material (see Japanese Patent Application Laid-Open No. 58-114084, etc.), or a silane coupling agent is previously treated on the substrate, and an extraction electrode is formed thereon. (JP-A-57-130015)
(See Japanese Unexamined Patent Publication (Kokai)).

On the other hand, in the case of a liquid crystal element, an insulating film is applied on two plastic substrates with transparent electrodes, a liquid crystal material is applied on the insulating film of one of the substrates, and then the other substrate is laminated. (Japanese Unexamined Patent Publication No.
-328612). Here, since the insulating film still has a problem in the smoothness of the plane of the transparent electrode on the plastic substrate, the insulating film is formed to prevent a short circuit between the two transparent electrodes. At this time, only one of the two substrates is removed on the four sides around the liquid crystal element, the surface of the transparent electrode of the other substrate is exposed, and this electrode is connected to an external power supply. Thereafter, the liquid crystal element is passed between a plurality of rollers, and while applying a shearing force to the sandwiched liquid crystal material, a voltage from an external power supply is applied between the transparent electrodes to orient the liquid crystal material. Here, the surface resistance of the transparent electrode provided on the plastic substrate for a liquid crystal element is usually 100
A high resistance type of about 300 Ω / □ is generally used. For this reason, the voltage supplied from the outside substantially decreases as the distance from the position where the external power supply is connected increases. Therefore, in a liquid crystal element having a particularly large area, in order to realize a uniform alignment state in a plane, it is necessary to form a low-resistance extraction electrode on the exposed transparent electrode. This extraction electrode is coated with a high-viscosity conductive paste in which conductive fine particles are dispersed in a binder resin and a small amount of solvent using a dispenser such as the paste coating device described above or a device such as a screen printing machine. It is formed by doing. Further, in a liquid crystal shutter as disclosed in Japanese Patent Application Laid-Open No. H11-38361, it is necessary to uniformly transmit and block light with respect to the supplied driving voltage. Therefore, after the liquid crystal is aligned and cut into a desired product size, only one of the substrates is half-cut to take out a transparent electrode, and a low-resistance common electrode is formed on the transparent electrode.

[0004]

In the manufacturing process of such a liquid crystal element, it is necessary to dry and cure the applied extraction electrode. However, in order to increase the efficiency of the process, it is conceivable to heat the extraction electrode. Can be However, in particular, in the case of a ferroelectric liquid crystal element, when heated to a certain temperature or higher, there is a possibility that the liquid crystal transitions to an isotropic phase and the alignment of the liquid crystal is disturbed.
For this reason, after applying the paste, it is necessary to dry the paste at room temperature for a long time, and there is a problem that the efficiency of the process is low. In addition, if a photocurable resin is used as the binder resin, it is possible to locally treat only the extraction electrode, but the problem cannot be solved in terms of improving the efficiency of the process.

Further, in the case of a plastic substrate, there is still a problem with the smoothness of the plane of the transparent electrode, and an insulating film is formed to prevent a short circuit between the two transparent electrodes. However, since the paste has a high viscosity, the paste does not penetrate into the insulating film, and the connection between the applied lead electrode and the transparent electrode on the substrate is poor. Therefore, it is necessary to once remove the insulating film on the transparent electrode to be taken out and then apply the paste, which also has a problem that the efficiency of the process is low.

An object of the present invention is to provide a paste coating apparatus, a method for forming an extraction electrode, and a liquid crystal element, which can improve the efficiency of the process.

[0007]

According to a first aspect of the present invention, a paste comprising a mixture of fine particles, a binder resin, and an organic solvent is discharged from a discharge head, and an extraction electrode is formed on a substrate disposed on a surface plate. Is characterized by comprising a paste accumulating section for accumulating a paste, and a paste stirring mechanism having a stirring member that reciprocates vertically while rotating within the paste accumulating section ( Claim 1). According to the first aspect, by stirring the paste accumulated in the paste accumulation unit with the stirring member, it is possible to always maintain the paste in a uniform dispersion state. For this reason, since the fine particles in the paste and the binder resin do not separate from each other, it is not necessary to increase the viscosity of the paste, and a low-viscosity paste can be used. Therefore, if a low-viscosity paste is used, it can be dried at room temperature in a short time as compared with the related art when applied, and
When an extraction electrode for supplying a voltage to the liquid crystal element is formed, the paste permeates the insulating film, so that there is no need to remove the insulating film, and an extraction electrode having good connectivity with the transparent electrode is obtained. It becomes possible. Thus, the efficiency of the manufacturing process of the liquid crystal element can be improved.

In the above, a magnetic field generating unit which moves up and down along the outer wall of the paste storing unit and generates a rotating magnetic field is provided in the vicinity of the above-mentioned paste storing unit. It is preferable to operate synchronously (claim 2). With this configuration, since the stirring member reciprocates up and down in the paste accumulation section while rotating in synchronization with the magnetic field generating section that reciprocates up and down, it is easy to always maintain the paste in a uniform dispersion state. It becomes possible. Further, since the stirring member can be rotated from the outside by the rotating magnetic field from the magnetic field generating unit, the configuration of the paste stirring mechanism can be simplified.

The above-mentioned ejection head is closed when the ejection head is not in contact with the substrate, and is controlled by pressing the substrate when the ejection head is in contact with the substrate. It is desirable that a valve mechanism be provided (claim 3). This makes it possible to control the discharge amount in accordance with the viscosity of the paste to be used and the wettability of the substrate surface, thereby making it possible to form an optimal coating film on the substrate surface.

Further, it is preferable that a discharge head position adjusting mechanism for adjusting the distance between the upper surface of the platen and the tip of the discharge head is provided. In this case, even when the substrate formed of a plastic film has undulations, the pressure applied to the ejection head is constant, whereby it is possible to easily eject a paste with a constant application amount. .

In addition, the apparatus may include a discharge head standby mechanism for holding the discharge head in an initial state and a standby state, and a discharge head immersion mechanism for immersing the discharge head in an organic solvent during a standby period of the discharge head standby mechanism. Desirable (claim 5). Here, when a low-viscosity paste having a large organic solvent content is used as the paste, a film formed by application is quickly dried at room temperature. On the other hand, after application, the paste adhered to the ejection head also dries quickly, so that the ejection port portion of the ejection head may be clogged while waiting for the next application. Therefore, after the ejection head is moved and the desired extraction electrode is formed, the ejection head is caused to stand by in an ejection head standby mechanism in an initial state, and during the standby period until the next coating, the ejection head is immersed in the organic solvent by the ejection head immersion mechanism. By immersing the paste in the paste, it is possible to prevent the paste adhered to the discharge head portion from drying and solidifying.

[0012] A second invention of the present invention is a method for forming an extraction electrode for forming an extraction electrode on a substrate, comprising:
The method includes a stirring step of stirring a paste made of a mixture of a binder resin and an organic solvent, and a discharging step of discharging the stirred paste to a substrate. Here, examples of the fine particles include conductive particles such as silver, silver-palladium alloy, copper, silver-copper alloy, nickel, and carbon black. Examples of the material of the binder resin include an acrylic resin, a phenol resin, a vinyl chloride resin, a polyolefin resin, an epoxy resin, a melamine resin, a polyester resin, an acrylate resin, and a rubber resin.

According to the second aspect of the present invention, by stirring the paste in the stirring step, the paste can always be maintained in a uniform dispersed state. For this reason, since the fine particles in the paste and the binder resin do not separate from each other, it is not necessary to increase the viscosity of the paste, and a low-viscosity paste can be used. Therefore, if a low-viscosity paste is used in the discharge process, it can be dried at room temperature in a shorter time than before, when applied, and an extraction electrode for supplying a voltage to the liquid crystal element. Is formed, the paste penetrates into the insulating film, so that it is not necessary to remove the insulating film, and it is possible to obtain an extraction electrode having good connectivity with the transparent electrode. Thus, the efficiency of the manufacturing process of the liquid crystal element can be improved.

In the above, at least one of the agitating step and the discharging step is performed in any one of claims 1 to 5.
(See paragraph numbers “0007” to “0011”). In this way, it is possible to obtain an extraction electrode having good connectivity with the transparent electrode by selecting a paste coating apparatus that matches the characteristics of the substrate, thereby improving the efficiency of the liquid crystal element manufacturing process. Can be further improved.

The above-mentioned paste has a viscosity of 50 cp.
It is preferably at least s and at most 400 cps (claim 8). In this way, the paste penetrates into the insulating film and reaches the surface of the underlying transparent electrode, so there is no need to remove the insulating film, and good connection between the extraction electrode and the transparent electrode can be obtained. Becomes possible. In addition, since the formed film becomes a thin film due to the low viscosity of the paste, the paste can be quickly dried even at room temperature. In addition,
If the viscosity of the paste is less than 50 cps, the film to be formed becomes too thin, and exceeds the resistance required for applying a voltage from an external power supply, which is not preferable.

According to a third aspect of the present invention, there is provided a liquid crystal device comprising at least one transparent substrate with electrodes and a liquid crystal material sandwiched between the substrates. The transparent electrode is a transparent electrode, and at least one of the transparent electrode-attached substrates is provided with an insulating film on the electrode, and the insulating film is provided on the insulating film.
(See paragraph numbers “0013” to “0015”). An extraction electrode to which a driving voltage application unit for driving the liquid crystal element is connected is formed by using the extraction electrode formation method described in any one of the paragraphs. The electrode is in contact with the electrode through the insulating film (claim 9).

Here, as the substrate, polyethylene terephthalate (PET), polyether sulfone (PE)
S), polycarbonate (PC), polyarylate (P
And a flexible plastic formed of a material such as Ar). In addition, as a material forming the insulating film, an organic polymer material, an inorganic material, or the like is used. From the viewpoint of the permeability of the paste, an organic polymer material is preferably used. As organic polymer materials, epoxy-based, acrylic-based, imide-based, fluorine-based, siloxane-based thermosetting resins, thermoplastic resins such as nylon, polyvinyl alcohol, and polyvinylidene fluoride, and acrylic-based and silicone-based resins UV curable resin such as a resin. Examples of the inorganic material include metal oxides such as silicon oxide, titanium oxide, aluminum oxide, and tantalum oxide. Such an inorganic material is preferably a thin film having a thickness of 0.1 μm or less in order to ensure the permeability of the paste. In the case of the exemplified materials, such a thin film has an effect as an insulating film. The liquid crystal material is not particularly limited as long as it exhibits liquid crystallinity at room temperature and has at least one kind of good solvent, and nematic liquid crystals and ferroelectric liquid crystals are used. Among them, a composition composed of a ferroelectric liquid crystal capable of achieving a large-screen, large-capacity display element with a simple configuration, that is, a ferroelectric liquid crystal composition is suitably used. Examples of the ferroelectric liquid crystal composition include a ferroelectric low-molecular liquid crystal, a ferroelectric polymer liquid crystal, and a mixture thereof. If a ferroelectric polymer liquid crystal is contained as a liquid crystal material, it is possible to form a liquid crystal having excellent film forming properties and alignment properties. As a ferroelectric polymer liquid crystal,
A side-chain type ferroelectric polymer liquid crystal exhibiting a chiral smectic C phase is exemplified. At this time, a non-liquid crystalline polymer substance may be mixed to improve the mechanical strength of the liquid crystal alignment.

According to the third aspect of the present invention, when forming the extraction electrode for supplying a voltage to the liquid crystal element, the paste to be the extraction electrode is simply applied onto the insulating film, and the paste is applied to the insulating film. The paste penetrates and the paste and the transparent electrode come into contact. Therefore, it is not necessary to remove the insulating film, and it is possible to obtain an extraction electrode having good connectivity with the transparent electrode, thereby making it possible to increase the efficiency of the manufacturing process of the liquid crystal element.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a paste coating apparatus 1 and a liquid crystal element 10 according to one embodiment of the present invention.

The liquid crystal element 10 includes a pair of transparent substrates 11A and 11B which are disposed to face each other, transparent electrodes 12A and 12B provided on respective opposing surfaces of the pair of substrates 11A and 11B, and It has insulating films 13A and 13B covering the electrodes 12A and 12B, respectively, and a liquid crystal 14 sandwiched between these insulating films 13A and 13B.

Next, each component of the liquid crystal element of the present embodiment will be specifically described. (1) Substrate The substrate used in the present invention is not particularly limited.
A flexible substrate such as a plastic substrate is suitably selected for improving productivity. As the material of the plastic, polyethylene terephthalate (PET), polyether sulfone (PES), polycarbonate (PC), polyarylate (PAr), and the like are preferable. The material of one of the two substrates may be the same as or different from that of the other substrate, but it is necessary that at least one of the substrates is transparent in terms of extracting light.

(2) Electrode The electrode may be made of a material having conductivity, but is provided on one of the transparent substrates in order to ensure the translucency of at least one of the transparent substrates. Examples include ITO made of indium oxide and tin oxide, and S
The electrode must be a transparent electrode using an electrode material such as nO ₂ . The electrode provided on the other substrate may be a transparent electrode or a metal electrode such as aluminum.

(3) Insulating Film Known materials such as an organic polymer material and an inorganic material can be used as a material constituting the insulating film. From the viewpoint of the permeability of the paste, an organic polymer material is preferably used. Specifically, as the organic polymer material, epoxy-based, acrylic-based, imide-based, fluorine-based, siloxane-based thermosetting resin, or nylon, polyvinyl alcohol, thermoplastic resin such as polyvinylidene fluoride, And ultraviolet-curable resins such as acrylic and silicone resins. Also, as an inorganic material,
Metal oxides such as silicon oxide, titanium oxide, aluminum oxide, and tantalum oxide can be given. Such an inorganic material is preferably a thin film having a thickness of 0.1 μm or less in order to secure the permeability of the paste. In the case of the exemplified materials, even such a thin film exhibits an effect as an insulating film. .

(4) Liquid Crystal As a liquid crystal material, it exhibits liquid crystallinity at room temperature and has at least 1
There is no particular limitation as long as the liquid crystal has more than one kind of good solvent,
Known liquid crystal materials such as a nematic liquid crystal and a ferroelectric liquid crystal can be used. Among them, a composition composed of a ferroelectric liquid crystal capable of achieving a large-screen, large-capacity display element with a simple configuration, that is, a ferroelectric liquid crystal composition is suitably used. As the ferroelectric liquid crystal composition, a ferroelectric low molecular liquid crystal, a ferroelectric polymer liquid crystal, a mixture thereof, or the like can be used. At this time, it is preferable to contain a ferroelectric polymer liquid crystal having excellent film-forming properties and orientation properties. Among them, a side chain type ferroelectric polymer liquid crystal exhibiting a chiral smectic C phase is preferably used. At this time, a non-liquid crystalline polymer substance may be mixed to improve the mechanical strength of the liquid crystal alignment.

On the other hand, the paste coating device 1 is
This is a device for forming an extraction electrode on the substrate 11A of the liquid crystal element 10 disposed thereon, and includes a paste application mechanism 2 for applying paste serving as an extraction electrode, a paste stirring mechanism 3 for stirring the paste, and a discharge. Head position adjustment mechanism 4
Ejection head standby mechanism 5 and ejection head immersion mechanism 6
And an XY moving mechanism 7 for operating the paste applying mechanism 2 in the horizontal and vertical directions.

Examples of the paste include a mixture obtained by mixing conductive fine particles, a binder resin, and an organic solvent. Here, examples of the fine particles include conductive particles such as silver, silver-palladium alloy, copper, silver-copper alloy, nickel, and carbon black. Examples of the material of the binder resin include an acrylic resin, a phenol resin, a vinyl chloride resin, a polyolefin resin, an epoxy resin, a melamine resin, a polyester resin, an acrylate resin, and a rubber resin. The organic solvent is preferably one that dissolves or swells the insulating film.
Since the film thickness is on the order of submicron, it is sufficient if there is some solubility. The viscosity of the paste used is 5
It is preferable that the range be 0 cps or more and 400 cps or less.

The paste application mechanism 2 includes a paste storage unit 21 for storing the paste and a paste
And an ejection head 22 for ejecting the ink to the XY moving mechanism 7 via the support 8.

The paste accumulating section 21 has a supply port 21A at the upper end to which the paste is supplied, and is for accumulating the paste put in from the supply port 21A. Any material can be used as the material of the paste storage section 21 as long as the material has resistance to an organic solvent, and examples thereof include glass and Teflon. The paste accumulating unit 21 is fixed to a support 8 attached to the XY moving mechanism 7 via a connecting member 9 so as to be vertically displaceable, and moves on the substrate 11A together with the ejection head 22. I have. In the conventional coating method, a vacuum suction mechanism is provided on a side opposite to a discharge direction to suction with a vacuum in order to remove a paste attached to a discharge port of a discharge head. However, when a vacuum suction mechanism is provided in the present invention, the concentration of the organic solvent changes and the properties of the applied film thickness change, which is not preferable.

As shown in FIG. 2, the ejection head 22 is closed when the ejection head 22 is not in contact with the substrate 11A, and is closed when the ejection head 22 is in contact with the substrate 11A. Has a valve mechanism 23 for controlling the opening degree by pressing the valve. Such a valve mechanism 23
Accordingly, the discharge amount can be controlled in accordance with the viscosity of the paste to be used and the wettability of the substrate surface, and an optimal coating film can be formed on the substrate surface. Specifically, the ejection head 22 is provided with a valve mechanism 23 composed of a spring 23A fixed to the paste accumulation section 21 and a substantially conical valve body 23B fixed to the tip of the spring 23A. . Valve body 23B
Is projected from the paste discharge port and is spherical so as not to damage the surface of the substrate 11A. Then, the spring 23A contracts in proportion to the pressure applied to the tip portion of the valve body 23B, and as a result, the discharge amount increases.

As shown in FIG. 3, the paste stirring mechanism 3 includes a stirring member 31 built in the paste storage section 21 and a magnetic field generating section 32. The stirring member 31 is made of rugby ball-shaped Teflon that reciprocates in the vertical direction while rotating in the paste accumulating section 21, thereby always keeping the paste in a uniform dispersed state. The magnetic field generation unit 32 is provided near the paste storage unit 21, moves up and down along the outer wall of the paste storage unit 21, and generates a rotating magnetic field, and includes a disk 33 and a motor 34. Have been. As a preferred form of the paste stirring mechanism 3 that reciprocates up and down while rotating the stirring member 31, as shown in FIG. 3, two magnets 33A are respectively provided with N poles and S poles in the paste accumulating section 21. A mechanism that is embedded in the disk 33 so as to face the outer wall side and is connected to the motor 34 and rotated. The disk 33 in which the magnet 33A is embedded and the magnetic field generating unit 32 including the motor 34 are vertically moved by an air cylinder 36 connected via an arm 35 that moves up and down by the height of the paste storage unit 21. Repeat the reciprocating motion. On the other hand, the paste accumulating section 21 has a stirring member 3 having a magnet embedded therein.
1 is pre-installed, so that it rotates in synchronization with the magnetic field generating unit 32 that reciprocates up and down while rotating, and reciprocates up and down in the paste accumulating unit 21, whereby the paste is always uniformly dispersed. Can be kept.

The ejection head position adjusting mechanism 4 includes a substrate 11A
The stopper 41 has a roller 41A attached to the lower end of the connecting member 9 and a micrometer 42 provided above the support 8 for adjusting the distance between the upper surface and the valve body 23B of the ejection head 22. And The stopper 41 is used to apply the paste to the ejection head 2.
2 comes down and comes in contact with the substrate 11A,
2 is prevented from lowering too much with respect to the substrate 11A. The roller 41A is attached to smoothly move the stopper 41 in contact with the substrate 11A when forming the application line. Micrometer 4
The second spindle is in contact with a stopper 43 fixed to the air cylinder 37. Therefore, by moving the spindle of the micrometer 42 forward and backward, the support 8
Moves up and down, so that the ejection head 22 with respect to the substrate 11A
Can be adjusted. Here, the position of the ejection head 22 is made closer to the substrate when applying to a substrate having undulations than when applying the substrate to a substrate having undulations. This makes it possible to stabilize the pressure of the ejection head 22 against the substrate 11A.

The ejection head standby mechanism 5 and the ejection head immersion mechanism 6 are mechanisms for holding the ejection head 22 in an initial state and waiting, and immersing the ejection head 22 in an organic solvent during a standby period. As the paste, a low-viscosity paste having a large organic solvent content is preferably used. Thereby, there is an effect that the film formed by application is quickly dried at room temperature. However, on the other hand, after the application, the paste attached to the ejection head 22 is also quickly dried. For this reason, after the application, the ejection head 22 may rise from the substrate surface and return to the origin, and the ejection port portion of the ejection head 22 may be clogged while waiting for the next application. In order to avoid this, after forming a desired extraction electrode, the ejection head 22 is caused to stand by in an initial state by the ejection head standby mechanism 5, and the ejection head 22 is moved by the ejection head dipping mechanism 6 during a standby period until the next coating. It is preferable to immerse the paste in the organic solvent to prevent the paste attached to the discharge head 22 from drying and solidifying.

Specifically, the ejection head standby mechanism 5
-Y moving mechanism 7. As shown in FIG. 4, the ejection head immersion mechanism 6 includes a container 52 for holding an organic solvent 51 and an organic solvent absorbing pad 53 having elasticity.
Consists of Here, as a specific material of the organic solvent absorbing pad 53 having elasticity, felt or the like can be used. When the application of the paste is completed, the ejection head 22 rises from the surface of the substrate 11A and returns to the origin. Thereafter, the ejection head 22 is lowered again, and the tip of the valve body 23B is pressed against the organic solvent absorption pad 53. At this time, if the ejection head 22 is directly immersed in the organic solvent 51,
It is not preferable because the organic solvent 51 flows back into the paste accumulation section 21 and changes the composition of the paste. Therefore, the pad 53 is in contact with the pad 53 that has absorbed the organic solvent 51. The upper lid 52A of the container 52 is provided with micro holes 52B for keeping the surface of the organic solvent 51 at atmospheric pressure and keeping the absorption pad 53 immersed in the organic solvent 51 at all times.

Next, the procedure for forming the extraction electrode will be described below. First, as a paste, conductive fine particles,
A mixture of a binder resin and an organic solvent is used. In particular, in the liquid crystal element 10, when the extraction electrode is formed on the extraction transparent electrode 12A provided with the insulating film 13A made of an organic polymer, the volume ratio between the organic solvent and the solid content (the binder resin and the fine particles) is set to 1 1.7 to 1:
0.6, and it is preferable to use a low-viscosity paste having a viscosity of 50 cps or more and 400 or less. By using such a paste, the paste penetrates into the insulating film 13A and reaches the surface of the underlying transparent electrode 12A.
There is no need to remove the insulating film 13A, and good connection between the extraction electrode and the transparent electrode 12A can be obtained. Further, since the paste has a low viscosity, the formed film becomes a thin film, so that the paste can be quickly dried even at room temperature. If the viscosity of the paste is smaller than 50 cps, the film to be formed is too thin, which is not preferable because it exceeds the resistance required for flowing a voltage from an external power supply. The above-mentioned paste is supplied to the paste accumulating section 21 of the paste applying apparatus 1 and the paste accumulating section 21
A stirring step of stirring the paste is performed in the inside, and the stirred paste is applied to the discharge head 22 on the insulating film 13A of the substrate 11A.
An ejection step for ejecting is performed. Thus, a substrate (liquid crystal element) on which the extraction electrodes are formed is obtained.

According to the present embodiment, the following effects can be obtained. That is, the paste coating device 1
By providing a paste storage unit 21 for storing paste and a paste stirring mechanism 3 having a stirring member 31 that reciprocates in the vertical direction while rotating in the paste storage unit 21, low-viscosity paste can be used. So you can
When applied, the paste can be dried at room temperature in a shorter time than before, and when an extraction electrode for supplying a voltage to the liquid crystal element 10 is formed, the paste is applied to the insulating film 1.
Since it penetrates into 3A, it is not necessary to remove the insulating film 13A, and it is possible to obtain an extraction electrode having good connectivity with the transparent electrode 12A. Thus, the efficiency of the manufacturing process of the liquid crystal element 10 can be improved.

Further, since the agitating member 31 reciprocates up and down in the paste accumulating section 21 while rotating in synchronization with the magnetic field generating section 32, the paste can always be easily maintained in a uniform dispersion state. Further, since the stirring member 31 can be rotated from the outside by the rotating magnetic field from the magnetic field generator 32, the configuration of the paste stirring mechanism 3 can be simplified.

Further, since the discharge head 22 is provided with the valve mechanism 23, the discharge amount can be controlled in accordance with the viscosity of the paste to be used and the wettability of the substrate surface. A film can be formed.

Further, since the ejection head position adjusting mechanism 4 is provided, even when the substrate has undulation, such as a substrate formed of a plastic film, the ejection head 22 can be used.
Is constant, whereby it is possible to easily discharge a paste with a constant application amount.

Since the discharge head standby mechanism 5 and the discharge head immersion mechanism 6 are provided, the discharge head 22 is moved to form desired extraction electrodes, and then the discharge head 22 is moved to the initial state by the discharge head standby mechanism 5. The discharge head 22 is immersed in the organic solvent absorbing pad 53 by the discharge head immersion mechanism 6 during the standby period until the next application, thereby preventing the paste attached to the discharge head 22 from drying and solidifying. be able to.

Further, since the agitation step and the discharge step are performed by the paste coating apparatus 1, it is possible to obtain an extraction electrode having good connectivity with the transparent electrode 12A, thereby improving the efficiency of the manufacturing process of the liquid crystal element 10. Can be further improved.

The viscosity of the paste is not less than 50 cps and not more than 400 cps.
Since it penetrates and reaches the surface of the underlying transparent electrode 12A, it is not necessary to particularly remove the insulating film 13A, and good connection between the extraction electrode and the transparent electrode 12A can be obtained. Further, since the paste has a low viscosity, the formed film becomes a thin film, so that the paste can be quickly dried even at room temperature.

Further, when forming an extraction electrode for supplying a voltage to the liquid crystal element 10, the paste which becomes the extraction electrode is merely applied onto the insulating film 13A, and the paste permeates into the insulating film 13A, And the transparent electrode 12A are in contact with each other, so that it is not necessary to remove the insulating film 13A from this point as well, and it is possible to obtain an extraction electrode having good connectivity with the transparent electrode 12A. Can be made more efficient.

It should be noted that the present invention is not limited to the above-described embodiment, but includes other configurations that can achieve the object of the present invention, and the following modifications are also included in the present invention.
For example, the viscosity of the paste is 50 cps or more and 40 cps or more.
It is not limited to 0 cps or less, and when it is applied, it penetrates into the insulating film, reaches the surface of the underlying transparent electrode, and does not need to remove the insulating film to obtain good connectivity between the extraction electrode and the transparent electrode. Any viscosity can be used as long as it is possible to determine the viscosity.

Further, as the stirring step and the discharging step,
Both steps are not limited to being performed by the paste application device, and for example, either one may be performed, or may be performed without using the paste application device.

Further, the ejection head standby mechanism and the ejection head immersion mechanism need not be provided if, for example, paste application is performed continuously.

As a discharge head position adjusting mechanism,
For example, if the operator adjusts the distance between the upper surface of the platen and the tip of the ejection head every time the paste is applied, the provision may be omitted.

Further, the valve mechanism may not be provided as long as the discharge amount can be controlled in accordance with, for example, the viscosity of the paste to be used and the wettability of the substrate surface.

The stirring member is not limited to being operated by the magnetic field generating unit, but may be rotated manually or by directly attaching a motor, for example, and may be appropriately selected in practice.

[0049]

Next, the effects of the present invention will be described based on specific examples. [Example 1] In Example 1, based on the above embodiment, a liquid crystal element was manufactured by employing the following specific procedure and the like.

As a substrate, a transparent electrode made of indium tin oxide (ITO) was formed on a polyethersulfone film, width 300 mm, length 500 mm, thickness 1
00 μm plastic substrate (Sumitomo Bakelite Co., Ltd.
FST). An insulating film was formed on each of the transparent electrodes of the two substrates.

As an insulating film material, a cyanoethylated pullulan (manufactured by Shin-Etsu Chemical Co., Ltd.) is used, and a 5% by weight mixed solution of methyl ethyl ketone / acetone is applied using a gravure coater, and dried at 140 ° C. for 4 minutes. Was. It was confirmed by an optical interference method that the thickness of the insulating layer formed here was about 0.2 μm.

Next, a liquid crystal layer was formed on the surface of one insulating layer of the substrate with an insulating layer. As a material for forming the liquid crystal layer, a ferroelectric liquid crystal composition containing a ferroelectric polymer liquid crystal and a polystyrene (molecular weight: 50,000) as a non-liquid crystal polymer material component having a content ratio of 4% by weight were used.
The material was used so that Here, the ferroelectric liquid crystal composition is composed of the following ferroelectric polymer liquid crystal A, low-molecular liquid crystal B, low-molecular liquid crystal C, and low-molecular liquid crystal D:
It is a composition mixed at a weight ratio of 3: 1: 1.

[0053]

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The liquid crystal component and the non-liquid crystal polymer component were dissolved in a common solvent, methyl ethyl ketone. A 28% by weight methyl ethyl ketone solution of the liquid crystal material prepared as described above was applied to the surface of the insulating film using a gravure coater. Then, another one of the substrates with an insulating film is laminated and bonded to the application surface of the liquid crystal material so that the insulating layer is in contact with the liquid crystal layer, and then only one of the substrates is cut by a cutter to have a width of 10 mm.
A transparent electrode was formed.

In preparation for performing the alignment treatment of the thus obtained liquid crystal element, an extraction electrode was formed by paste on the transparent electrode on four sides. As the paste, a silver paste (Doitite D-500 manufactured by Fujikura Kasei, viscosity: 100)
00 cps) and ethyl acetate at a volume ratio of 1: 1. When the viscosity of this paste was measured using a viscometer, it was 125 cps.

As a coating device, a paste coating device combining the respective mechanisms shown in FIGS. 1 to 4 was used. The inner diameter of the paste accumulation section is 15 mm, and the volume is 20 cc. Only 18 cc of the silver paste was injected into the paste accumulation section. Then, the position of the tip of the ejection head is 5 mm from the upper surface of the liquid crystal element (200 μm thick) arranged on the surface plate.
The ejection head was set on the substrate at a speed of 5.4 cm / sec by setting a micrometer so that the ejection head was lowered by 00 μm.

An operation for moving the discharge head is performed.
A paste was applied to the upper and lower sides having a length of 500 mm. And
By leaving at room temperature for 10 minutes, it was dried to a tack-free state. Next, the liquid crystal element was turned over, and paste was applied to the left and right sides having a length of 300 mm in the same procedure, left at room temperature for the same time, and dried. Then, while applying a DC voltage of 40 V between the two substrates via the extraction electrode, the liquid crystal was subjected to a bending deformation to perform an alignment treatment of the liquid crystal, thereby obtaining a liquid crystal element of Example 1.

[Embodiment 2] In this embodiment 2, a siloxane-based thermosetting resin is used as an insulating film material for forming an insulating film. Obtained. Specifically, a product obtained by adding an alkoxysilane having an amino acid, an alkoxysilane having a glycidyl group, and an alkoxysilane at a weight ratio of 1: 1: 1 was used. Ethanol was added thereto, and the mixture was coated on a polyethersulfone (PES) substrate under the same conditions as in Example 1 and heated. The thickness of the obtained insulating film is 0.
It was 16 μm. Then, using the same material and apparatus as in the first embodiment, the liquid crystal is subjected to alignment treatment, and the second embodiment is performed.
Was obtained. The drying time of the applied silver paste was 10 minutes, which was the same as that in Example 1.

Comparative Example 1 A liquid crystal device was manufactured in the same manner as in Example 1 except that the following points were changed. That is, in the paste application device, the method of stirring the paste is changed. Specifically, a stirring member was fixed to the lower end of the paste accumulation unit, and the stirring was performed by rotating the stirring member with a motor. With this stirring method, the color of the lower part of the paste accumulation part is darker,
The upper color was nearly transparent, indicating that a sufficient stirring effect was not exhibited.

Comparative Example 2 A liquid crystal element was manufactured in the same manner as in Example 1 except that the following points were changed. That is, silver paste (（10000 cps)
The amount of ethyl acetate added to
s.

Comparative Example 3 A liquid crystal device was manufactured in the same manner as in Example 1 except that the following points were changed. That is, in the paste coating device, the ejection head position adjusting mechanism was removed.

[Evaluation of Liquid Crystal Element] Each of the liquid crystal elements obtained in Examples 1 and 2 and Comparative Examples 1 to 3 was evaluated for the following points. (1) Width and Thickness of Extraction Electrode On the upper and lower sides of the substrate having a length of 500 mm, measurement was made every 50 mm.

(2) Contrast Ratio and Response Time The obtained liquid crystal element is inserted between two neutral polarizers arranged in a crossed Nicols state, the voltage applied to the liquid crystal element is set to 15 V, and the polarity is switched between positive and negative. , The light and dark states of the liquid crystal element were alternately repeated. Using a halogen lamp as a light source, the amount of transmitted light was measured in each state, and the ratio was defined as a contrast ratio. By measuring the in-plane distribution of the contrast ratio, it is possible to determine whether or not a voltage is uniformly applied in the plane. For this measurement, nine points were measured in an area of 500 mm × 300 mm. The time change of the transmitted light amount was taken into a digital oscilloscope, and the time required for the transmitted light amount to change from 10% to 90% was measured with the transmitted light amount in the bright state being 100% and the transmitted light amount in the dark state being 0%. By measuring the response time near the extraction electrode, it is possible to determine whether or not the connectivity between the transparent electrode and the extraction electrode is good. In this measurement, the response time of the application start portion and the end portion of the extraction electrode was measured for four sides of the liquid crystal element.

Based on the results of each evaluation, Table 3 summarizes the average value and the value obtained by multiplying the standard deviation by three as an index of the variation. As shown in Table 1, in Examples 1 and 2, good results were obtained. However, in Comparative Examples 1 and 2, the width of the extraction electrode was smaller at the end portion than at the coating start portion, and as a result, the contrast ratio and the response time varied. Further, in Comparative Example 3, the width of the extraction electrode had a large variation,
Along with this variation, in-plane unevenness of the contrast ratio was observed.

[0065]

[Table 1]

[0066]

As described above, according to the paste coating apparatus, the method for forming the extraction electrode, and the liquid crystal element of the present invention, there is an effect that the efficiency of the process can be improved.

[Brief description of the drawings]

FIG. 1 is a front view showing a paste application device according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a valve mechanism of a discharge head according to the embodiment.

FIG. 3 is an enlarged view showing a paste stirring mechanism in the embodiment.

FIG. 4 is a schematic diagram showing a discharge head standby mechanism and a discharge head immersion mechanism in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paste coating device 3 Paste stirring mechanism 4 Discharge head position adjustment mechanism 5 Discharge head standby mechanism 6 Discharge head immersion mechanism 10 Liquid crystal element 11A, 11B Substrate 12A, 12B Transparent electrode 13A, 13B Insulating film 14 Liquid crystal 21 Paste accumulating part 22 Discharge head 23 Valve mechanism 31 Stirring member 32 Magnetic field generator 100 Surface plate

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H092 GA32 HA06 HA12 HA16 MA10 MA35 NA27 PA01 QA07 QA13 4D075 AC06 AC84 AC88 AC92 AC93 AC94 AC95 AC96 BB16Z BB20Z BB92Z BB93Z BB95Z CA48 DA06 DB14 DC22 EA14 4F041 BA22 AB BA60

Claims (9)

[Claims] 1. A paste coating apparatus for discharging a paste made of a mixture of fine particles, a binder resin, and an organic solvent from a discharge head to form an extraction electrode on a substrate disposed on a surface plate, wherein the paste is accumulated. And a paste stirring mechanism having a stirring member that reciprocates vertically while rotating within the paste storage section. 2. The paste application device according to claim 1, wherein the paste stirring mechanism is provided near the paste storage unit, moves up and down along an outer wall of the paste storage unit, and generates a rotating magnetic field. A paste applying device, comprising: a magnetic field generating unit for causing the stirring member to operate in synchronization with the magnetic field generating unit. 3. The paste coating apparatus according to claim 1, wherein the discharge head is closed when the discharge head is not in contact with the substrate, and the discharge head contacts the substrate. A paste mechanism which is provided with a valve mechanism for controlling the degree of opening of the substrate by pressing the substrate when the substrate is being pressed. 4. The paste coating apparatus according to claim 1, further comprising a discharge head position adjusting mechanism for adjusting a distance between an upper surface of the platen and a tip of the discharge head. A paste application device characterized by the above-mentioned. 5. The paste coating device according to claim 1, wherein the discharge head standby mechanism causes the discharge head to be in an initial state and waits, and wherein the discharge head standby mechanism controls the discharge head during a standby period. A paste coating device, comprising: a discharge head dipping mechanism for dipping the discharge head in an organic solvent. 6. A method for forming an extraction electrode for forming an extraction electrode on a substrate, comprising: a stirring step of stirring a paste composed of a mixture of fine particles, a binder resin, and an organic solvent; And discharging the substrate to the substrate. 7. The method for forming an extraction electrode according to claim 6, wherein at least one of the stirring step and the discharging step is performed by the paste coating apparatus according to any one of claims 1 to 5. A method for forming an extraction electrode. 8. The method for forming an extraction electrode according to claim 6, wherein the paste has a viscosity of 50 cps or more and 400 cps or less. 9. A liquid crystal device comprising two substrates with electrodes, at least one of which is transparent, and a liquid crystal material sandwiched between the substrates, wherein the electrodes attached to at least one of the transparent substrates are:
A transparent electrode, wherein the at least one transparent electrode-attached substrate is provided with an insulating film on the electrode, and the insulating film is provided on the insulating film.
An extraction electrode to which a driving voltage application unit for driving the liquid crystal element is connected is formed by using the extraction electrode formation method according to claim 8, wherein the extraction electrode penetrates the insulating film. And a liquid crystal element which is in contact with the electrode.