JPH0460613A - Production of liquid crystal panel - Google Patents

Abstract

PURPOSE:To precisely and thinly control an intersubstrate gap by forming microadhesive points on a 1st substrate surface, applying a liquid crystal material on a 2nd substrate, pressing both substrates, and curing the adhesive points thereof. CONSTITUTION:The microadhesive points 2 contg. spacer particles 3 are formed substantially over the entire surface of the 1st substrate 1 in a 1st stage. The liquid crystal material 5 is dropped or applied on the 2nd substrate 4 surface opposing to the above-mentioned substrate in a 2nd stage. The two substrates 1, 4 are stuck and pressed to each other in a 3rd stage. The pressing is executed by putting, for example, the stuck panel into a vacuum bag and sucking the inside of the bag with a vacuum pump, etc., to pressurizing the substrates 1, 4 from both sides nearly uniformly with the atm. pressure. The panel which obviates the fluctuation in the intersubstrate gap of the panel against external force and has the sufficient durability as an optical element is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing panels useful for liquid crystal displays or liquid crystal/yantars.

Conventional technology response speed is 2 digits compared to conventional TN type liquid crystal and STN type liquid crystal 2.
・Although there are expectations for the next-generation high-speed response, high-definition displays and high-speed optical printers for liquid crystals that are three orders of magnitude faster, they have not yet been put into practical use due to the following problems. .

In other words, unlike TN type elements and STN type elements, in ferroelectric liquid crystal elements, the gear metal λ between the substrates constituting the panel is
This is a problem that arises because it is extremely thin (μm) and cannot be used as an optical response element unless gear irregularities are suppressed within the panel surface, otherwise the arrangement of liquid crystal molecules will be disordered and it cannot be used as an optical response element. It is.

The seventh problem is that the liquid crystal injection time is extremely slow due to the small gap between the substrates.
For example, when injecting forced crystals between 30×30 substrates, if we use vacuum capillary injection, which is difficult to achieve with conventional TN-type or STN-type devices, we can inject 77g of crystal between 30×30 substrates. At the same time, at least 6 hours of crazy time is required.
This method was extremely inefficient in terms of industrial production.

In order to solve this problem, in order to solve this problem,
/3, Japanese Patent Publication No. 1983, 2-/ Aj612, Japanese Patent Publication No. 1987-
/! j'61.23, Tokukaihei! -Ta 3! For r/1%, a method has been disclosed in which a glass and a liquid crystal tube are pasted on the board surface and the surrounding area is fixed with adhesive, but in these cases, 'fti Although the crab injection time can be reduced by a large amount per day, the problem of the λth cannot be solved.

In other words, the second problem is that the gap between the substrates must be precisely and thinly controlled. It is necessary to configure the panel so that the gap does not narrow or widen.

As mentioned earlier, even if you fix only the periphery of the panel with N adhesive,
When external pressure is applied to the central part of the panel, the gap becomes small when the substrate is deflected, and at this moment the arrangement of the Kg crystals is irreversibly disturbed.

In order to prevent this, the prior art discloses that the substrates are bonded together after spraying soot with a certain particle size between them, but this is certainly true. Although it becomes more resistant to suppression and prevents the cell gap from narrowing, for example,
), when a horizontal force is applied to the panel, or when a shock is applied, the /g of the channel will easily expand by L due to the deflection of the board, and the liquid crystal will instantly change. This irreversibly disturbs the array state and causes a single problem, which is essentially unanswered.

Means and action for solving all the problems The above problems can be completely solved by the following method of the present invention. That is, (1) a step of forming minute adhesive dots containing all the spacer particles on substantially the entire surface of the first substrate; a step of dropping or coating a liquid crystal material on the opposing surface of the second substrate; This was achieved using artificial panel manufacturing method 2, which involves repeating the process of laminating and inserting the panels and the process of hardening the adhesive points.

The entire process and function of this website will be explained using Figure 1.

In the first section (A), / is a substrate, 2 is a minute adhesive point, and 3 is a spacer particle included in the minute adhesive.

As shown in the figure, the micro adhesive is spread over the entire surface of the substrate in an uncured state in a spherical or rondo shape (in the case of a spherical shape, the diameter is 10 mm).
0 μm or less, preferably 60 μm or less (in the case of a rond shape, one corner is ioo μm or less, preferably 60 μm or less) printed by means such as letterpress or intaglio, and this includes a diameter of about λ μm. A large number of spacer particles are dispersed. The number of minute adhesive points within a plane is 0.3 pieces/mm or more, and for striped ones 0.3 pieces/mm
The above is preferable.

Next, in FIG. 1(B), ≠ indicates the opposing first substrate, j
is a liquid crystal. The amount of liquid crystal to be coated is preferably slightly larger than the volume of voids in the panel after completion = 9.

FIG. 1 (() shows the state in which the substrates of (A) and (B) above are laminated and pressed uniformly. For insertion, put the pasted panel into a vacuum bag and use a full vacuum tube to vacuum the inside of the bag, then apply pressure evenly from both sides of the board at atmospheric pressure. Particularly, the deformation of the adhesive progresses slowly, and the deformation of the adhesive ends when the gap between the substrates is determined by the pressure of 7L and the diameter of 1 length. At this time, the liquid crystal also spreads in the gap between the substrates and spreads across the entire gap between the substrates.

After completing this process, or in parallel with this process, the temperature of the entire panel will be raised! lll, the viscosity of the liquid crystal in a highly viscous paste-like state decreases rapidly,
Fills the gaps between Zenels evenly over the entire surface.

At the same time, if the adhesive is a thermosetting resin,
As the adhesive begins to harden, surprisingly, it pushes away the liquid crystal that was on the surface of the substrate and acts directly on the surface of the substrate, firmly adhering and fixing the substrate. . The leftover liquid crystal seeps out from the surface of both boards.

If the adhesion agent is i: curable, the curing agent should be irradiated with 1 x 1 during this temperature raising process.

Thus, &! according to the present invention! In the case of Tenmanshi, the liquid crystal was injected at the same time as the panel was formed. In ff'81, it is necessary to take the trouble to fix the upper and lower substrates in a furnace due to the large number of small contact points. Since it does not disturb the alignment state of the liquid crystal, it depends on whether it has sufficient f@#i characteristics as an optical element. It is surprising that a liquid crystal material exhibits remarkable adhesion even on the at'1-layer surface.

Although not shown in Figure VC, in the broader scope of the present invention, even if an adhesive layer is formed on the periphery of the substrate as a /-ru material and then pressed, excess liquid crystal metal will be released. I turned all the way around to get out of the way, and without giving in, I opened all the exits and turned.
After the curing is completed, it is preferable to seal the external η and rako with abrasive resin or the like. Although it is important to keep t% of the surrounding/ru material, at the initial stage of the 1!5 base mounting stand, the upper and lower boards are tightly connected to each other, so you can see the advantage of improving the workability of TJ6. .

In addition, since these minute adhesion points are very small, when the display is closed, it is almost impossible to cover all the rows on the screen, which has a negative visual impact.

Since the adhesive used in the present invention involves a printing process, it is necessary to use an adhesive with a long pot life.For example, a thermosetting adhesive such as Structobo For epoxy-based adhesives and UV-curable adhesives, go to Takuya Gosei Co.

In order to completely set the gap between the substrates, it is necessary to knead an inorganic or organic mobilizing force into the adhesive material, and a gap material in the shape of a spherical or rond shape. As for the sub-column, P material is Showa Denko's Alfit, Nippon Electric Glass's P material.
F/II-s, Catalysts Kasei Kogyo Co., Ltd. Shinka Ball Series,
Seeds of M-machine polymer materials: Micropearl manufactured by Chemical Co., Ltd., Eposter manufactured by Nippon Shokubai Chemical Co., Ltd., Toshiba Ricoh 7
Toss Zell and others at the company's front page are furious. Also, especially the board or 10
When the size is larger than mnr, the above-mentioned spacers may be appropriately dispersed in order to further improve the uniformity of the cell gaps.

The shape of the adhesive in the present invention may be dot-like or stripe-like, but it is also possible to use a mixture of both. Further, short stripes may be disposed continuously.

Transparent and transparent electrodes are provided on the substrate used in the present invention.
There is no limit to the size of the material, but glass and plastic are usually preferred. Above 1! On the substrate with poles,
In order to obtain the alignment of the forced injection liquid crystal, it is necessary to provide an alignment film. This kind of alignment film is generally made of materials such as polyimide, polyamide, polyester oxide, polyhinyl alcohol, polyester, polyether sulfo/, polysulfone, nylon/, polycarbonate, cellulose derivatives, etc. A thin film of a polymer or a plasma polymerized film can be preferably used. Also, if necessary,
You can also use an inorganic thin film sound such as 5L02. It is desirable that the thin films of these ILs be subjected to a total treatment of at least 1.2% and 10,000 % of the substrate in order to promote the alignment of the liquid crystal. Furthermore, although the method of the present invention is fully effective when manufacturing ferroelectric liquid crystal panels, it can of course be applied to TN type and STN type liquid crystal panels.

Practical row/) Oh, L, 1TQ (Innoum, tin oxide Rica)
Polyimide LXs Hirooo manufactured by Hitachi Chemical Co., Ltd. was completely coated as an alignment film on the transparent electrode consisting of a transparent electrode, and baked at 3rs"c for 7 hours. A glass plate of !(7)×'jB with a thickness of /,/mm was subjected to rubbing treatment. On this substrate, as a gap material, an adhesion agent with a diameter of λ μm made by Shinbosu Kasei Kogyo Co., Ltd., and a diameter f of Structoho/do X7tttyo made by Mitsui Toatsu Co., Ltd. were applied.
) Approximately 7 30 μm dots are printed by letterpress printing, "mm
Printed on 2. O, ooty are placed in the center of f-4 of the opposite substrate, which is coated with an alignment film on the transparent electrode and rubbed in a shell-like manner.
When I put a C3-i 0/J made by Tyranno Corporation on the ferro-torturism liquid crystal and stuck both substrates together and pressed them down lightly, the liquid crystal spread in a circular shape between the gaps 9 and about 1/3 of the plane. 1 in the area of
Wide and next. In this state, put Nominel into a vacuum plastic bag.
After reducing the pressure in one bag to 2/mrnHg, heat it for 7 hours and heat cure it in an oven at /30''C for 7 hours.
When I removed the panel from heat exchange, the entire surface was filled with liquid crystal. In this state, the liquid crystal that had oozed out slightly was wiped off, and the glass was sealed with "C Stratat Bond x 7≠T0", which was then cured again at 300C for an hour and allowed to cool.

In this panel, the liquid crystals are carefully distributed, and even though the panel was exposed to medium heat for 10 years (all D holes were ≠ 0), there was no disturbance in the distribution of γL.

2) In the same manner as in 7, strip-like adhesive printing was applied to the first substrate surface. The cast density at this time is O0
jN/F717F+, it was set to -25 μm.

The same adhesive composition was screen-printed in stripes along the periphery of the opposing second radix, on the periphery/-l rigid. At this time, create a notch with a length of 0 mm in the middle heat part of the side of @4 as an outlet for discharging the liquid crystal. o, o at the center of this eye and the second board surface.
o6g ferroelectric liquid crystal manufactured by Robic L)C)F-θθ
o4! After dripping in a line in the direction of direct firing with the f-contact stripe on the substrate facing all the lamps, and pasting the two substrates together, vacuum punctures 1 to 1 were applied in the same manner as in row-7. Heat cut at 730°C/hour and cooled in room @1. In the resulting 7g flannel, the liquid crystals were arranged tightly over the entire surface, and the liquid crystal was dropped from the height of the ball tube of the medium heat Vc/θ of this flannel.
It does not emit light and has good impact resistance.

Comparison! ! Row 2: All panels for comparison were made in exactly the same manner as Tenmi Example 2, except that printing of minute adhesive dots was not performed at all. In this panel as well, the liquid crystals were arranged in a wide array, but there was one in the center of this panel.
0? When the hole fell from the SCM tube-hole, a local disturbance of orientation occurred, which could not be repaired and was rare.

Comparison 1-2 Next, create a panel and create an empty cell with no liquid crystal in it in the same manner as in process-2 except that the liquid crystal gold is not placed on the second substrate surface. The empty cells were placed in a full vacuum oven and vacuumed thoroughly to prevent separation between the cells. 1010mm1-
It took a total of 3 hours to reduce the pressure at 1/7 under conditions where no 2/2 swell occurred. During this period, the temperature was raised to /sO'C in order to promote the removal of scum within the cell. The sickle, implementation row-2
The same Kinjing/100CKIJ was hot, and when I touched the cutout of the cell, I injected the liquid crystal into the cell using a capillary tube, but it took half an hour to finish filling it.

This cell is removed from a cooling wave vacuum orb/9. Next,
The liquid crystal was almost well oriented within the resulting ξ channel, but
In some places, during press-fitting, there was some disturbance in the routing, which I thought was caused by the liquid crystal entering and drifting.

Father, is there a 70 in the center of this panel? of, h −le i≠oc
There were six missing pages due to the height of rn, but no tags t were oriented due to this n.

Comparison of practical rows 1 and 11 and comparison rows 11 and 11 shows that the method of the present invention results in crystalline/flannel resistance 'f: shortened injection time, good arrangement, and good yxrh impact resistance. ? It is obvious that getting a worthy nominee is a big deal.

[Brief explanation of the drawing]

Figure 1 (A) shows the III of the first substrate after applying the minute bonding points.
It is an enlarged view of the IJ plane, / is the substrate, - is the minute bonding point, 3
The lotus is one length particle. FIG. 1(B) is an enlarged surface view of the opposing λ-th substrate, μ is the substrate, and j is the liquid crystal. FIG. 1(C) is a side view of the panel after the substrates have been bonded and pressed.

Claims (5)

[Claims] (1) A step of forming minute adhesive dots containing spacer particles on substantially the entire surface of the first substrate, a step of dropping or coating a liquid crystal material on the opposing first substrate surface, and then pasting both substrates together. A method for manufacturing a liquid crystal panel, comprising at least the steps of combining and pressing together and curing the adhesive points. (2) A method for manufacturing a liquid crystal panel according to claim 1, characterized in that a seal made of adhesive is formed on the peripheral portion of at least one of the first and second substrates. (3) The method for manufacturing a liquid crystal panel according to claim 1, wherein the adhesive is a thermosetting resin or a photocurable resin. (4) The method for manufacturing a liquid crystal panel according to claim 1, wherein the liquid crystal material is a ferroelectric liquid crystal. (5) The method for manufacturing a liquid crystal panel according to claim 1, which comprises heating after lamination.