JP4104706B2 - Liquid crystal display device manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a liquid crystal display element in which the amount of spacers provided between two substrates of the liquid crystal display element can be made constant. More specifically, a liquid crystal display in which the spacer between the two substrates is fixed by dispersing the spacers on the substrate for a certain period of time while the spacer density in the chamber is constant. The present invention relates to a method for manufacturing an element.
[0002]
[Prior art]
The liquid crystal display element is provided by providing transparent electrodes, alignment films, etc. on two insulating transparent substrates made of glass, etc., providing a sealing agent around the cell of one substrate, and spraying spacers on the other substrate. Each substrate is attached so that a transparent electrode and an alignment film are opposed to each other so as to have a constant gap through a spacer, and after dividing into each cell, a gap between the two substrates is filled with a liquid crystal material, and both outer surfaces thereof are filled. It is manufactured by sticking a polarizing plate or the like.
[0003]
This spacer spraying method is, for example, by arranging a substrate for spraying the spacer at the bottom of the chamber, and spraying the spray liquid provided by dispersing the spacer in the solvent together with the atomized compressed air from the spray nozzle provided at the top of the chamber. Spray for about a few seconds. Then, for example, it is performed by allowing the spacer floating in the chamber to settle for a certain period of time of about 30 seconds. Thereafter, the chamber is evacuated for a certain period of time to remove excess solvent and spacers remaining in the chamber. The substrates on which the spacers are dispersed are sequentially taken out, for example, one by two from a cassette that contains dozens of sheets, and are carried into the chamber by a conveyor, and the substrates that have been dispersed are transported by the conveyor again into another cassette. It is stored and sprayed onto the substrates in the cassette in sequence. When spraying to the substrate in the cassette is completed, the cassette is replaced and spacers are sprayed in the same manner.
[0004]
[Problems to be solved by the invention]
According to the above-described spacer spraying method, after spraying the previous substrate, the floating spacer in the chamber is evacuated and a new substrate is placed in the chamber, and a certain amount of spray liquid is placed in the chamber. The spraying amount is applied so that a certain amount of spacers are dispersed. However, even if evacuation is performed for a certain period of time after spraying on a single substrate, the spacers in the chamber do not disappear completely, and a certain amount of spacers are floating, and the floating spacers settle with time. The amount of spacers floating in the chamber varies depending on the time until the next substrate is loaded. When the next substrate is carried into the chamber, if the floating spacer is not constant, the floating spacer in the chamber is not constant even if a certain amount of spray liquid is sprayed. In particular, after replacing the cassette, or after interruption due to line trouble, the substrate supply interval becomes longer, so the number of spacers floating in the chamber decreases, and even if a certain amount of spray liquid is sprayed, it floats. Spacer density is not constant. As a result, even if the substrate is placed in the chamber and left for a certain period of time, a certain amount of spacers do not settle on the substrate, resulting in a non-uniform spacing between the substrates of the liquid crystal panel and a deterioration in display quality. .
[0005]
The present invention has been made to solve such a problem, and provides a method of manufacturing a liquid crystal display element capable of always spraying constant spacers even when the carry-in interval of the substrate into the chamber can be changed. It is in.
[0006]
[Means for Solving the Problems]
A method for producing a liquid crystal display device according to the present invention is a liquid crystal display in which a transparent electrode and an alignment film are formed on a substrate, two spacers are adhered by spraying spacers, and a liquid crystal material is filled in the gap between the two substrates. A manufacturing method of the element,
Spray when cormorants rows spraying the spacers, checks whether preparation of the substrate is made, if the preparation of the substrate is possible with regular intervals, perform the loading of the substrate, to spray liquid in the chamber After a series of spraying steps consisting of settling of spacers floating in the chamber after standing for a certain period of time and exhausting in the chamber and discharging the substrate, the next substrate is carried in and the above series of spraying steps are performed. If the substrate preparation is not completed when the series of spraying steps is completed after the substrate preparation is delayed than usual, the series of spraying steps is regularly repeated without loading the substrate. Then, the substrate is carried into the chamber in accordance with the timing before spraying the sprayed liquid in the series of spraying steps, and the series of spraying steps is performed. That is, as a result of the study by the present inventors, it was found that there is a correlation between the amount of spacers floating in the chamber and the amount of spacers deposited on the insulating transparent substrate, and the density of the spacers in the chamber Is set to be in a constant state, and the spacer is allowed to settle on the substrate, whereby a certain amount of the spacer is dispersed on the substrate.
[0007]
Specifically, the cycle of spraying the dispersion, settling for a certain time, and exhausting for a certain time is regularly adjusted according to the time schedule of a normal spraying process (spraying, leaving for settling, and exhausting), for example. If the loading of the substrate is delayed due to replacement of the cassette, etc., this step is performed without loading the substrate (pseudo-spraying in which the spraying step is performed without the substrate), and the substrate is aligned with the timing before the next spraying. The process can be carried in, or the above process can be repeated periodically in accordance with the substrate carry-in interval at the time of cassette replacement. The former is preferable because the tact time can be shortened and it is easy to maintain a high spacer density in the chamber.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, a method for producing the liquid crystal display element of the present invention will be described.
[0009]
In the liquid crystal display element, an electrode pattern is formed on a transparent conductive film such as ITO on each of two insulating transparent substrates such as glass and plastic, an alignment film is formed, and then spacers are dispersed on one substrate. Then, the two substrates are bonded with a sealant, and divided into each cell or frame shape, and then the liquid crystal material is filled in the gap between the two substrates. As described above, the manufacturing method of the liquid crystal display element of the present invention is based on the knowledge that there is a correlation between the amount of spacer floating in the chamber and the amount of spacer sinking on the substrate. A feature is that the number of spacers interposed between two substrates is made uniform by allowing the spacers to settle on the substrate while maintaining the amount of spacers to be kept constant. The spacer spraying method will be described with reference to the flowchart of FIG. 1 and a schematic diagram of an example of the spacer spraying apparatus shown in FIG.
[0010]
In the spacer spraying apparatus shown in FIG. 2, an exhaust pipe 3 is connected to the lower part of the chamber 1 via an exhaust butterfly valve 2 so that the residue in the chamber 1 can be exhausted. . The chamber 1 is, for example, a 1.5 m square and is formed in a stainless steel box shape having a height of about 2 m, and the exhaust pipe 3 has a diameter of about 10 cm, for example, and a thickness of 1 to 1.3 m / sec. Exhaust at a moderate speed. A spray nozzle 4 is provided in the upper portion of the chamber 1, and the spray liquid 5 is sent into the spray nozzle 4 via the pump P. In the example shown in FIG. 1, a pipe is provided so that the spray liquid 5 in the spray nozzle 4 can be circulated with the spray liquid 5 in the container 52, and a rotor (Teflon) is provided in the container 52 by a magnet stirrer 53. The sprayed liquid 5 is agitated via a magnet 54 coated with the sprayed nozzle 54 so that the sprayed liquid 5 in the spray nozzle 4 does not become non-uniform over time. In addition to the pipe for sending the spray liquid 5, the atomizing gas 6 made of N ₂ or the like for atomizing the spray liquid 5 is introduced into the spray nozzle 4 through the gas passage. In the chamber 1, the temperature in the chamber 1 is not shown in the figure so as to be constant, for example, about 60 ° C., in order to prevent a temperature drop due to vaporization heat when spraying the spray liquid 5 and to facilitate evaporation of the solvent of the spray liquid. A heater is provided. As the spray liquid 5, for example, a silica spherical spacer having a diameter of 5.6 μm dispersed in a solution obtained by mixing ethyl alcohol and pure water in a ratio of 1: 1 was used.
[0011]
The insulating transparent substrate 30 is accommodated in the cassette 31 and placed on the loader 21, where it is placed on the conveyor 22 one by one and carried to the bottom 1 a of the chamber 1. It is transported by the conveyor 23 and stored in another cassette 32 by the unloader 24.
[0012]
Next, a specific example of a method of spraying spacers on the substrate 30 on which the electrode pattern and the alignment film are formed using the spacer spraying device will be described with reference to the flowchart of FIG.
[0013]
First, when the spraying operation is started, it is determined whether or not the substrate 30 is prepared (S1). The preparation of the substrate 30 means that the substrate 30 is taken out from the cassette 31 and transported by the conveyor 22 to stand by before the loading door 11 of the chamber 1. If the substrate has been prepared (YES), it is checked whether or not one cycle of the spraying process (steps S5 to S7 described later) has been completed (S2), and if not completed (NO), the process waits for completion. If completed (YES), the carry-in door 11 is opened, the substrate 30 is set on the bottom 1a in the chamber 1 and the carry-in door 11 is closed (S3), and a predetermined amount of spray liquid is sprayed into the chamber (S5). If the substrate 30 is not ready (NO in S1), it is similarly checked whether or not one cycle of the spraying process has been completed (S4). If not completed (NO), the process returns to step S1. If completed, the process proceeds to a step (S5) of spraying a predetermined amount of spray liquid into the chamber 1 without carrying in the substrate. Thereafter, the spray nozzle or the like is closed and left for a predetermined time of, for example, about 30 seconds (S6), and the spacer floating in the chamber is naturally dropped onto the substrate 30. Next, the exhaust valve 2 is opened and exhausted for a predetermined time of, for example, about 1 to 3 seconds (S7). After the elapse of time, the discharge door 12 is opened, the substrate 30 is discharged from the chamber 1 (S8), the discharge door 12 is closed, and the same process is repeated from step S1. The time from discharge of the substrate 30 to loading of the next substrate is usually about 3 to 4 seconds, and the cycle from loading of the substrate to loading of the next substrate is performed in about 40 seconds.
[0014]
That is, in the present invention, the steps from S5 to S7 are always repeated in a predetermined cycle, and even when the substrate is not ready, spraying of sprayed liquid, leaving for a predetermined time, and exhausting are constant without loading the substrate. It is characterized in that it is repeated in a cycle and the substrate is carried into the chamber in accordance with the timing. For example, in order to take out the substrate 30 stored in the cassette 31 and carry it into the chamber, it takes about 40 seconds to prepare for loading. In this cycle, the substrate can be loaded one after another and the spacers can be dispersed in a certain cycle. . However, when there is no substrate in the cassette and the cassette is replaced, it usually takes about 1 minute to carry the substrate from the replaced cassette into the chamber. In the present invention, because of this cassette replacement, if the substrate is not ready for loading at an interval of about 40 seconds, the spraying process is performed without loading the substrate (pseudo spraying), and the substrate is ready for loading. It waits without carrying in a board | substrate until the next spraying process starts (in the said example, about 20 seconds). Conventionally, the spraying operation is stopped during this exchange, and after the substrate is loaded and the substrate is loaded (interval is about 1 minute), spraying of the sprayed liquid is performed. Although the interval is long and is not constant, in the present invention, a cycle of this series of steps is performed at a constant interval.
[0015]
In the above example, the substrate is loaded in accordance with one cycle of the normal spraying process, and in special cases, the spraying process is always performed in a fixed time by performing pseudo spraying, but the spraying process is performed according to the interval at the time of cassette replacement. It is also possible to set one cycle. In this case, the spraying process time becomes long and waste occurs, and it is not possible to cope with a delay in board loading due to an accident. The same homogenization can be achieved by a simple process of taking in and out.
[0016]
FIG. 3 shows the result A of measuring the amount of spacers on the actual substrate on which the spacers are scattered by this method, together with the result B of the method of performing the spraying process in accordance with the loading of the substrates regardless of the conventional interval. In FIG. 3, the horizontal axis indicates the number of the processing order of the substrates, and the cassette is switched every 13th sheet (dashed line R). As is apparent from FIG. 3, according to the present invention, a constant spraying amount can be always obtained regardless of the switching of the cassette. On the other hand, in the conventional method, a drop in the number of spacers appears when the cassette is switched, and it can be seen that the effect of the present invention is greatly exhibited.
[0017]
In the above example, a spherical spherical spacer made of silica was used as the spacer, but the same result was obtained with plastic beads. Further, in the above-described example, the spray amount of the spray liquid from the spray nozzle is assumed to be constant, and only the spray time is constant, but in the case where the state of the nozzle or the pressure of the atomized gas is not constant, It is preferable to control the weight of the sprayed liquid 5 placed in the container 52 (see FIG. 2) with a decrease amount while measuring the weight of the sprayed liquid 5 with an electronic balance or the like, so that a constant sprayed liquid can be sprayed into the chamber.
[0018]
【The invention's effect】
According to the present invention, the dispersion amount of the spacers on the substrate is always constant by a very simple method, so that the distance between the substrates of the liquid crystal panel is always constant, and the liquid crystal display element of stable quality with excellent display quality. Is obtained.
[Brief description of the drawings]
FIG. 1 is a flowchart illustrating an example of a spacer spraying procedure according to an embodiment of a method for producing a liquid crystal display element of the present invention.
FIG. 2 is an explanatory diagram of an example of a spacer spraying device.
FIG. 3 is a diagram showing a change in spacer density as a result of examining a change in the amount of spraying depending on a substrate when the spacers are sprayed according to the flowchart of FIG. 1;
[Explanation of symbols]
1 Chamber 4 Spray nozzle 5 Spray liquid 6 Atomizing gas 30 Substrate

Claims (1)

A method for producing a liquid crystal display element, comprising forming a transparent electrode and an alignment film on a substrate, spraying spacers to adhere two substrates, and filling a gap between the two substrates with a liquid crystal material,
Spray when cormorants rows spraying the spacers, checks whether preparation of the substrate is made, if the preparation of the substrate is possible with regular intervals, perform the loading of the substrate, to spray liquid in the chamber After a series of spraying steps consisting of settling of spacers floating in the chamber after standing for a certain period of time and exhausting in the chamber and discharging the substrate, the next substrate is carried in and the above series of spraying steps are performed. If the substrate preparation is not completed when the series of spraying steps is completed after the substrate preparation is delayed than usual, the series of spraying steps is regularly repeated without loading the substrate. after could, in accordance with the timing before spraying of the spray solution of the series of spraying step was carried into the substrate into the chamber, preparation of the liquid crystal display device that performs the series of spraying process.

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