JPH04324827A - Liquid crystal injection method - Google Patents

Abstract

PURPOSE:To permit complying with demand for many-sort, small quantity production by achieving injection of liquid crystal panel by panel, and to enhance the efficiency of using the material for the liquid crystal. CONSTITUTION:An exfoliatable resin is applied to around the liquid crystal injection hole in a panel 1 so as to provide a simple sump 6 for liquid crystal, and inside of the panel 1 is evacuated, and then a material to liquid crystal is put in this liquid crystal sump 6, and injection is performed. After inside of the panel 1 is filled with liquid crystal, the sump 6 is removed, and the injection hole is blocked.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display element used in image display devices, computer terminals, optical shutters, etc., and more particularly to a method of injecting liquid crystal into a panel that will become a display element.

0002

[Prior Art] Liquid crystal display elements, which first appeared for displays in clocks, calculators, etc., have come to be used in a wide range of fields including computer terminals, optical shutters, and other applications other than display, as image quality has improved and larger sizes have increased. Ta. In principle, a liquid crystal display element is an electro-optical element that controls light passing through the element by applying a voltage to a liquid crystal sandwiched between substrates on which electrodes are formed. In recent years, a type of liquid crystal display element called an active matrix type in which switching elements are formed on a substrate surface to improve display characteristics has been actively developed, but the basic structure and operation are the same.

[0003] Next, an outline of the general manufacturing process of a liquid crystal display element will be described below. (1) The ITO film formed on the glass substrate is patterned to form driving electrodes. (2) An organic film for liquid crystal alignment is formed on the surface on which the electrodes are formed by printing and baking. (3) Orienting the surface of the organic film. (4) Two glass substrates that have been subjected to orientation treatment are placed facing each other with a certain distance between them and bonded together with an adhesive. (5) Cutting and separating the glass substrate into predetermined panel shapes. (6) Inject liquid crystal into the panel. (7) Connect the panel to the driving circuit.

Among the above steps, those related to the present invention are (
Since this is the liquid crystal injection part of step 6), this step will be explained in more detail using diagrams. FIGS. 2(a) and 2(b) are diagrams showing a conventional liquid crystal injection method, with (a) being a front view and (b) being a side view. In FIGS. 2(a) and 2(b), 1 is a panel, 2 is an adhesive, 3 is an injection port, 4 is a liquid crystal, and 5 is a liquid crystal dish. Next, the injection procedure will be explained.

The liquid crystal dish 5 containing the liquid crystal 4 and the panel 1 are set in a vacuum device. Conventional methods typically involve implanting multiple panels at once. At this time, the panel 1 and the liquid crystal 4 are not brought into contact with each other yet. Next, the inside of the device is evacuated, the pressure inside the panel 1 is reduced, and the gas dissolved in the liquid crystal 4 is degassed. When the inside of the panel 1 reaches a predetermined degree of vacuum, the injection port 3 of the panel 1 is brought into contact with the liquid crystal 4, and then the inside of the vacuum device is returned to normal atmospheric pressure. Then, due to the pressure difference, the liquid crystal 4
gradually enters the panel 1 through the injection port 3 (the state shown in FIG. 2). When the inside of the panel 1 is completely filled with liquid crystal, the panel is taken out and the injection port 3 is sealed with adhesive.

A liquid crystal display element is completed by connecting a driving circuit to a panel filled with liquid crystal in the manner described above.

[0007]

Problems to be Solved by the Invention The above-mentioned conventional liquid crystal injection method has the problem that the liquid crystal usage efficiency is low, and since injection is performed in lots, the work efficiency is poor and it is difficult to cope with high-mix, low-volume production. Even with the method shown in FIG. 2, it is theoretically possible to inject liquid crystal into the panels one by one. However, in reality, it is difficult to implement this method due to cost disadvantages such as the need to prepare a large number of liquid crystal plates. Therefore, injection is basically performed on a lot-by-lot basis, which is inefficient and unsuitable for high-mix, low-volume production.

Furthermore, in the method shown in FIG. 2, if the injection port moves away from the liquid crystal surface even for a moment during injection, gas will enter the panel, resulting in poor injection. Therefore, the liquid crystal pan must contain more liquid crystal material than is actually injected into the panel. Furthermore, since some liquid crystal materials are used repeatedly, there is a risk that the characteristics of the liquid crystal materials may change. This is because the ratio of each component in the liquid crystal material may change due to a difference in vapor pressure since the liquid crystal material is evacuated.

[0009]

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and it is possible to create a liquid crystal plate by applying a peelable resin on the panel to create a simple liquid crystal reservoir. To realize a liquid crystal injection method which enables injection of each panel one by one without using any liquid crystal and has high liquid crystal use efficiency.

0010

[Operation] By pouring the liquid crystal material into the liquid crystal reservoir provided on the panel, the liquid crystal pan used in the conventional method is completely unnecessary, and it becomes possible to inject one panel at a time. In addition, only the amount of liquid crystal material required for one panel is added to the liquid crystal reservoir, and since it is not used repeatedly, the characteristics of the liquid crystal material do not change.

[0011]

EXAMPLES The present invention will be explained in detail with reference to Examples below. (First Embodiment) FIGS. 1(a) and 1(b) are diagrams showing a liquid crystal injection method according to a first embodiment of the present invention, in which (a) is a cross-sectional view, and (b)
) is a plan view. In FIGS. 1A and 1B, 1 is a panel, 2 is an adhesive, 3 is an injection port, 4 is a liquid crystal, and 6 is a liquid crystal reservoir.

Next, a specific injection method will be explained step by step. (1) A releasable resin is applied using a dispenser or the like around the injection port 3 of the panel 1, in which two substrates are bonded together and cut into a predetermined shape, and then hardened to produce the liquid crystal reservoir 6. (2) Set the panel 1 in a vacuum device with the side on which the liquid crystal reservoir 6 is formed facing up, and evacuate it. (3) When the interior of the panel 1 reaches a predetermined degree of vacuum, a predetermined amount of liquid crystal 4 is poured into the liquid crystal reservoir 6. (4) Return the inside of the vacuum device to normal atmospheric pressure and take out the panel 1 from the vacuum device. Then, due to the pressure difference, the liquid crystal 4 is gradually injected into the panel 1 through the injection port 3 (the state shown in FIG. 1). In the conventional method, it was necessary to take out the liquid crystal pan at the same time as many panels, or to leave it in a vacuum device until the liquid crystal was completely injected into the panel, but with the method of the present invention, the panel could be taken out. You can immediately start the next injection. (5) When the inside of the panel 1 is completely filled with the liquid crystal 4, the liquid crystal reservoir 6 made of peelable resin is removed and the injection port 3 is sealed with adhesive.

The removable resin used here includes, for example, urethane-based and rosin-based resins, but there is no fear that they will react with the liquid crystal material after curing and change the properties of the liquid crystal.
Moreover, there is no particular restriction as long as it can be peeled off with a slight force after curing. As a result of adopting the liquid crystal injection method of this example,
It is now possible to inject individual panels, making it easier to handle high-mix, low-volume production. Furthermore, since there is no need to prepare more liquid crystal material than necessary and use it repeatedly, the usage efficiency of the liquid crystal is improved and there is no need to worry about deterioration of characteristics. (Second Embodiment) FIGS. 3(a) and 3(b) are diagrams showing a second embodiment of the present invention, in which (a) is a plan view and (b) is a sectional view. In FIGS. 3A and 3B, 1 is a panel, 2 is an adhesive, 3 is an injection port, 4 is a liquid crystal, and 6 is a liquid crystal reservoir made of a peelable resin. The only difference from the first embodiment is that the injection port 3 is located on the screen rather than at the edge of the panel 1, and the injection procedure is exactly the same as the first embodiment.

The advantage of the method of the second embodiment is that the injection can be performed before cutting and separating the bonded glass substrates into specific shapes. Therefore, it is suitable for cases where the size of the panel is relatively small and a large number of panels are produced from one set of glass substrates. Therefore, in this embodiment, there is not much merit in being able to inject each panel one by one, and the main effect is to improve the usage efficiency of the liquid crystal material.

[0015]

[Effects of the Invention] As explained above, by using the injection method of the present invention, it is possible to inject liquid crystal into each panel, which not only greatly improves work efficiency, but also improves the usage efficiency of liquid crystal materials and prevents characteristic deterioration. can also be prevented.

[Brief explanation of the drawing]

FIG. 1(a) is a cross-sectional view showing a liquid crystal injection method according to a first embodiment of the present invention. (b) is a plan view showing the liquid crystal injection method according to the first embodiment of the present invention.

FIG. 2(a) is a front view showing a conventional liquid crystal injection method. (b) is a side view showing a conventional liquid crystal injection method.

FIG. 3(a) is a plan view showing a second embodiment of the present invention. (b) is a sectional view showing a second embodiment of the present invention.

[Explanation of symbols]

1 Panel 2. Adhesive 3 Inlet 4.LCD 5. Liquid crystal dish 6 Liquid crystal reservoir

Claims (1)

[Claims] [Claim 1] In a liquid crystal injection method in which liquid crystal is injected into a panel consisting of a pair of substrates facing each other with a fixed interval, a simple liquid crystal reservoir is created on the panel and after the injection is completed. , a liquid crystal injection method characterized by removing the liquid crystal reservoir.