JPH0785146B2 - Liquid crystal display cell manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a liquid crystal display cell using a flexible film such as a plastic film as a substrate.

2. Description of the Related Art A liquid crystal display cell displays a pattern by encapsulating a liquid crystal substance between opposed substrates provided with electrode patterns and applying a signal voltage to electro-optically modulate the liquid crystal substance. Conventionally, inorganic glass has been used as a substrate, but a flexible film such as plastic is used from the viewpoints of thinning, weight reduction, size increase, curved surface display, strength and manufacturing cost. The liquid crystal display cell, which has been used in the past, is receiving attention.

To make such a liquid crystal display cell, for example,
As shown in each member in FIGS. 15 and 16, first, two substrates 11 and 12 on which a transparent electrode 41 is formed and an alignment film 43 is applied are used, and a spacer 45 is interposed between these substrates, and an outer peripheral portion thereof is formed. Is sealed with a sealing material except the liquid crystal injection port 17 to form a seal portion 13 to obtain a liquid crystal cell, and then a liquid crystal substance is formed by a vacuum injection method.
Fill 31. The vacuum injection method uses the pressure difference between the atmospheric pressure applied to the liquid crystal and the vacuum in the liquid crystal cell by immersing the liquid crystal injection port 17 of the liquid crystal cell in the liquid crystal substance in a vacuum and then returning the pressure to the atmospheric pressure. Is a method of injecting. In the cell in which the liquid crystal substance is injected in this way, as shown in FIGS. 15 and 16, generally, bubbles 33 remain inside the cell,
In addition, the cell thickness is formed to be larger than the diameter of the spacer 45.
In such a state, liquid crystal display quality with high reliability and display quality cannot be obtained.

Therefore, as shown in FIG. 17 and FIG. 18, after injecting the liquid crystal, by sequentially applying pressure in the direction of the injection port 17 from the opposite side of the injection port with a roll or the like, the excess liquid crystal substance in the cell A method is used in which bubbles are transferred toward the inlet and discharged.

However, this method can effectively discharge the bubbles remaining in the vicinity of the inlet as shown in FIG. 19 and FIG. 20, but it becomes difficult to discharge the bubbles as the distance from the inlet becomes longer,
It was extremely difficult to completely remove bubbles in a cell having a large display area.

Japanese Laid-Open Patent Publication No. 59-119325 discloses a segment display type liquid crystal display cell in which a gate (opening) is provided in a part of a sealing material on a side facing a liquid crystal inlet of the liquid crystal cell, and a bubble storage portion connected to the gate. Is provided on the outer peripheral side of the sealing material, and when the liquid crystal is filled in the liquid crystal cell, the bubbles are pushed up and sent to the bubble storage part, and after the liquid crystal is filled, the bubble storage part is cut off and positioned on the opposite side of the liquid crystal chamber. It has been proposed to seal the gate and the liquid crystal inlet with epoxy resin.

However, in this method, it is necessary to separately seal the two positions of the liquid crystal injection port and the gate with epoxy resin, and in the XY matrix type liquid crystal display element, it is necessary to take out the signal electrode and to connect with the external electrode. There is a problem that connection is difficult. In the case of a segment electrode as shown in JP-A-59-119325, the electrode can be drawn out and connected to the outside by using the side that is not cut or sealed with a sealing agent, but it is of a matrix type. In the liquid crystal display element, it is necessary to draw out and connect the electrodes in both X-Y directions (both vertical and horizontal sides), and this becomes difficult if the liquid crystal inlet and the gate are located on the opposite sides.

OBJECT OF THE INVENTION The present invention can effectively prevent the remaining of air bubbles, and further,
It is an object of the present invention to provide a method for manufacturing a liquid crystal display cell in which an electrode can be led out in the Y direction and can be connected to the outside.

According to the method of manufacturing a liquid crystal display cell of the present invention, the opposing flexible film substrates are sealed by an inner seal portion except for the liquid crystal inlet, and a liquid crystal chamber is formed in a portion surrounded by the counter substrate and the inner seal portion. And an outer seal portion is formed on the outer peripheral portion of the inner seal portion, and a liquid crystal inflow passage is formed in a portion surrounded by the outer seal portion, the inner seal portion, and the counter substrate. The liquid crystal inlet is sealed at the position farthest from the liquid crystal inlet or in the vicinity of the gold, and is closed by the outer seal except that it has at least one communication opening and opens to the liquid crystal chamber, and Is used to form a closed end by extending from the communication opening to the vicinity of the liquid crystal injection port, and a liquid crystal substance is introduced into the liquid crystal cell from the liquid crystal injection port to fill the liquid crystal chamber. At the same time, the liquid crystal substance is caused to flow into the liquid crystal inflow path from the communication opening toward the closed end of the liquid crystal inflow path, and the bubbles remaining in the liquid crystal cell are transferred to the closed end, and then the liquid crystal inflow path is closed. It is characterized in that the vicinity of the closed end is removed.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a plan view showing an embodiment of a liquid crystal cell used in the present invention, in which opposing flexible substrates 11 and 12 are sealed by an inner seal portion 13, and the substrates 11 and 12 and the inner seal portion are sealed. 1
A liquid crystal chamber 15 surrounded by 3 is formed. Inner seal part 1
3 has a liquid crystal inlet 17. An outer seal portion 21 is formed on the outer peripheral portion of the inner seal portion 13, and a portion surrounded by the outer seal portion 21, the inner seal portion 13 and the substrates 11 and 12 is a liquid crystal inflow path 23.
Is formed. The liquid crystal inflow path 23 is sealed except for opening and communicating with the liquid crystal chamber 15 via a communication opening 19 provided in the inner seal portion 13. The communication opening 19 opens in the liquid crystal chamber 15 near the position farthest from the liquid crystal inlet 17.

When a liquid crystal substance is injected into this liquid crystal cell by the vacuum injection method, the liquid crystal substance flows into the liquid crystal chamber 15 from the liquid crystal inlet 17 to fill the liquid crystal chamber 15 as shown by the arrow in FIG. It flows into the liquid crystal inflow path 23 through the communication opening 19 and fills up in sequence. At this time, bubbles 33 remaining in the liquid crystal chamber 15
Is transferred to the liquid crystal inflow path 23 along the flow of the liquid crystal substance,
Finally, as shown in FIG. 3, it is driven into the closed end portion 23a of the liquid crystal inflow path 23 located beside the liquid crystal inlet 17.

Then, as shown in FIG. 4, air bubbles 33 are formed at the BB cutting line.
The closed end portion 23a into which is driven is cut and removed. After that, excess liquid crystal is extruded by rolling similar to the conventional method, and the opening is sealed with a sealant 25 such as epoxy resin,
A liquid crystal display cell as shown in FIG. 5 is obtained.

This liquid crystal display cell effectively prevents bubbles from remaining in the cell, and has a double seal structure of an inner seal portion and an outer seal portion, which is excellent in mechanical strength such as impact resistance. At the same time, the barrier property is improved and the reliability is increased. Even if air or moisture enters from the outside through the outer seal portion, they are trapped in the gap between the outer seal portion and the inner seal portion. The liquid crystal chamber 15 functions as an effective display area, while the liquid crystal inflow path 23 functions as a bubble discharge path when the liquid crystal display cell is formed and as a trap portion after the liquid crystal display cell is formed. Further, the portion to be cut and removed is sufficient only on the liquid crystal injection port 17 side, so that the liquid crystal injection port 17 and the liquid crystal inflow path opened by cutting can be simultaneously sealed with the sealant 25 such as an epoxy resin. Moreover, since it is not necessary to cut the substrates 11 and 12 on the side of the communication opening 19 on the side facing the liquid crystal injection port 17, the lower substrate 12 can be left in a state of protruding from the upper substrate 11. Therefore, as shown in FIG. 20, the transparent electrode 41 on the line formed on the lower substrate 12 can be drawn to the outside by using this protruding portion, and the connection with the external electrode can be made. Is also easy. Line-shaped transparent electrodes 41 are also formed on the above-mentioned substrate 11, and the upper and lower substrates are formed.
The 11, 12 transparent electrodes 41, 41 form an XY matrix. In FIG. 20, 43 is an alignment film and 45 is a spacer.

The case where the liquid crystal inflow path is formed in the gap between the inner seal portion and the outer seal portion to form the double seal structure has been described above, but the liquid crystal cell used in the present invention is not limited to this.

Further, it is not necessary to provide the liquid crystal inflow passage in the entire outer peripheral portion of the inner seal portion, but it may be provided in a part as shown in FIG. 6, for example.

7 to 14 are plan views showing another embodiment of the liquid crystal display cell obtained by the present invention, showing various modes of the communication opening. The shape of the liquid crystal cell suitable for producing this liquid crystal display cell will be apparent from the comparison between FIG. 1 and FIG.

In FIG. 7, the communication openings 19 are unevenly distributed from the center, and in FIG. 8, there are two communication openings 19 and 19.
In FIG. 9, two communication openings 19, 19 are provided, and a double seal structure is realized over substantially the entire circumference of the liquid crystal chamber 15.

In FIGS. 10 and 11, a flow control seal portion 27 is provided in front of the communication opening 19 in order to prevent backflow of the liquid crystal substance and control the flow.

In FIGS. 12 to 14, the communication opening 19 has a certain length to control the flow.

In any of the above cases, since there is a portion of the lower substrate 12 protruding from the upper substrate 11, X
The line-shaped transparent electrode 41 in the direction can be drawn out and connected to the external electrode.

EFFECT OF THE INVENTION According to the method for producing a liquid crystal display cell of the present invention, with a relatively simple cell structure, and by the vacuum injection method excellent in productivity, the remaining of bubbles in the cell is effectively prevented, High reliability can be obtained by preventing adverse effects such as deterioration of the alignment film due to gas, particularly oxygen or water vapor. Further, if there are bubbles, they appear as black dots, but since they disappear, high quality liquid crystal display is possible. Therefore, a cell having a large display area, which has been difficult to manufacture due to the remaining bubbles, can be prepared, and a liquid crystal display cell using a plastic film as a substrate can be upsized.

Further, since the substrate can be cut only on one side having the liquid crystal injection port, transparent electrodes can be drawn out from the upper and lower substrates in the XY directions and connected to the outside, and a liquid crystal display cell having a matrix type electrode can be realized. .

[Brief description of drawings]

FIG. 1 is a plan view of a liquid crystal cell used in the present invention. 2, 3, and 4 are views for explaining a method for manufacturing a liquid crystal display cell of the present invention. 5 to 14 are plan views showing an embodiment of the liquid crystal display cell of the present invention. It should be noted that in the above and below plan views, the sealing member is shown by the hatched portion. 15 to 20 are views for explaining a method for manufacturing a conventionally manufactured liquid crystal display cell, and FIG. 15 is a plan view and FIG.
FIG. 17 is a sectional view taken along the line AA in FIG. 15, FIG. 17 is a plan view, FIG. 18 is a sectional view taken along the line A′-A ′ in FIG.
19 is a plan view and FIG. 20 is a sectional view taken along the line A "-A" in FIG. 11,12 …… Flexible substrate, 13 …… Seal part 15 …… Liquid chamber, 17 …… Liquid crystal inlet 19 …… Communication opening, 21,21 ′ …… Outside seal part 23 …… Liquid crystal inlet 23a ...... Closed end of liquid crystal inflow path 25 …… Sealant 27 …… Seal part for flow control 33 …… Bubbles 41 …… Transparent electrode 43 …… Alignment film 45 …… Spacer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takamichi Enomoto 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) Reference JP-A-59-119325 (JP, A) JP-A-57 -171319 (JP, A)

Claims (1)

[Claims] 1. A flexible film substrate facing each other is sealed by an inner seal portion except a liquid crystal injection port, a liquid crystal chamber is formed in a portion surrounded by the counter substrate and the inner seal portion, and the inner seal portion is further provided. An outer seal portion is formed on an outer peripheral portion of the liquid crystal, and a liquid crystal inflow passage is formed in a portion surrounded by the outer seal portion, the inner seal portion, and the counter substrate, and the liquid crystal inflow passage is the liquid crystal furthest from the liquid crystal injection port. At a position inside the room or in the vicinity thereof, except for having at least one communication opening and opening to the liquid crystal chamber, the liquid crystal is sealed by the outer seal portion, and the liquid crystal inflow path is provided from the communication opening to the liquid crystal injection port. A liquid crystal cell that extends to the vicinity of the liquid crystal cell and forms a closed end is introduced, and a liquid crystal substance is introduced into the liquid crystal cell from the liquid crystal inlet to fill the liquid crystal chamber and liquid crystal flows from the communication opening. The liquid crystal substance is caused to flow into the liquid crystal inflow path toward the closed end of the liquid crystal, the bubbles remaining in the liquid crystal cell are transferred to the closed end, and then the vicinity of the closed end of the liquid crystal inflow path is removed. A method of manufacturing a characteristic liquid crystal display cell.