JP2822621B2 - Manufacturing method of liquid crystal display element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a method for manufacturing a liquid crystal display element, which aims to improve the accuracy and workability of alignment of upper and lower glass substrates and shaping and cutting of substrates, and also to improve yield and reduce cost. In a method for manufacturing a liquid crystal display element, two glass substrates facing each other via a gap-shaped space are sealed with a sealing layer, and a liquid crystal is injected and sealed into the gap-shaped space. When forming an electrode, a position recognition mark is simultaneously formed on the substrate surface outside the seal layer, and then, when forming an alignment film, a planarization protective film is formed simultaneously over the position recognition mark. The liquid crystal display device is manufactured as described above.

[Industrial applications]

The present invention relates to a method for manufacturing a liquid crystal display element, particularly, a display panel (empty cell) before liquid crystal injection.

In recent years, the development of display devices has been remarkable, and in particular, flat displays have rapidly spread in terms of thinness and light weight. Above all, liquid crystal display devices have low drive voltage and are inexpensive, and therefore are actively introduced into OA equipment fields such as personal computers and word processors.

As liquid crystal display elements have become larger and more precise, their manufacturing techniques have become more sophisticated, and there is a demand for the development of manufacturing methods with higher precision and higher working efficiency.

[Conventional technology]

The use of STN (Super Twisted Nematic) liquid crystal for liquid crystal display devices, especially liquid crystal display devices for graphics display, has made it possible to increase the size and capacity of liquid crystal display devices. It is necessary to manufacture a liquid crystal display panel (referred to as an empty cell) before injecting with high precision and efficiently.

FIG. 4 is a view showing a panel configuration of a liquid crystal display element, showing a state of an empty cell before liquid crystal is injected. FIG. 4 (a) is a top view, FIG. 4 (b) is a partially enlarged view, FIG. (C) is a sectional view.

In the figure, reference numerals 1a and 1b denote transparent glass substrates, on which are formed transparent electrodes 2a and 2b made of, for example, known ITO (In ₂ O ₃ —SnO ₂ ). Alignment films 3a and 3b are formed on the transparent electrodes 2a and 2b in the display area, respectively. The alignment film is obtained by, for example, coating a polyimide resin film and then rubbing with a cloth such as nylon to perform an alignment treatment.

The two glass substrates 1a and 1b thus formed are arranged orthogonally so that the alignment films 3a and 3b face each other as shown in the figure and the respective transparent electrodes 1a and 1b form a matrix intersection. A spacer 4, for example, a small ball made of polyester resin is sandwiched between the substrates, and sealed with a seal layer 5 made of an adhesive. A liquid crystal injection port 50 for injecting a liquid crystal later is provided in a part of the seal layer 5.

60 is a position recognition mark, for example, as shown in FIG.
A double square, for example, an upper glass substrate
1a is provided with an outer square 60a, and the lower glass substrate 1b is provided with an inner square 60b. When the transparent electrodes 2a and 2b are formed on the respective substrates, at least two of these position recognition marks 60 are simultaneously formed, for example, at diagonal corners of the substrate as shown in the figure.

When the two glass substrates 1a and 1b are bonded together in the above arrangement, for example, the position recognition mark 60 is placed in the large square of the position recognition mark 60a of the upper substrate, Manually align the small squares under a microscope, or automatically align them with an image recognition alignment device using a TV monitor and mechanically clamp them, or use an ultraviolet curable resin or the like. After temporary bonding, the sealing layer 5 is heat-bonded and cured to form empty cells. The position recognition mark 60 can be recognized using the fact that the reflectance is different from that of the glass substrate.

When the glass substrate 1 is shaped and cut as necessary after bonding the two substrates, for example, the position recognition mark 60 is read by an automatic cutting device, and the position recognition mark 60 is read.
Each cutting line, for example, the dash-dot lines X ₁ -X ₁ and X ₂ -X ₂ for the upper substrate, and the dotted lines Y ₁ -Y ₁ and Y ₂ -Y ₂ for the lower substrate from the positional relationship between After the determination, the glass substrates 1a and 1b are automatically scribed along each line to produce an empty panel for display, and, for example, after the STN liquid crystal is injected from the liquid crystal injection port 50, the liquid crystal injection port 50 is It manufactures liquid crystal display elements for display by hermetically sealing.

[Problems to be solved by the invention]

However, the conventional position recognition mark 6 (6a, 6b)
For example, since it is formed simultaneously with the transparent electrode 2 (2a, 2b) made of ITO, it usually has a thickness of 100 to 200 nm,
During the alignment treatment of the alignment film 3 (3a, 3b), rubbing cloth or other dust may adhere due to the steps.

FIG. 3 is a view showing an example in which dust adheres to a conventional position recognition mark. FIG. 3 (a) is a top view and FIG. 3 (b) is a sectional view. Here, an alignment film 3 (3a, 3b) made of, for example, a polyimide resin film is provided on the transparent electrode in the display area inside the seal layer 5 (not shown). In the figure, reference numeral 80 denotes fiber scraps of a rubbing cloth attached to the position recognition mark 6a of the upper glass substrate 1a, and reference numeral 90 denotes a lower glass substrate.
For example, the rubbing cloth fiber scraps attached to the position recognition mark 6b of 1b.

The same parts as those described in the above drawings are denoted by the same reference numerals, and the description of the same parts will be omitted.

As described above, if the dust 80 or 90 adheres to the position recognition mark 6, the image recognition of the position recognition device becomes inaccurate or impossible, and the accuracy of bonding the substrates and the accuracy of cutting and shaping the substrates are reduced. As a result, problems such as deterioration of product quality and yield have arisen, and solutions have been required.

[Means for solving the problem]

The above object is achieved by a method for manufacturing a liquid crystal display device, comprising sealing a glass layer facing two glass substrates via a gap-like space with a sealing layer and injecting and sealing a liquid crystal into the gap-like space. When forming a transparent electrode on the substrate, a position recognition mark is simultaneously formed on the substrate surface outside the seal layer, and then, when forming an alignment film, a flattening protective film covering the position recognition mark is simultaneously formed. The problem can be solved by manufacturing a liquid crystal display element so as to be formed.

[Action]

According to the method of the present invention, at the time of forming the alignment film 3, at least two position recognition marks 6 provided on the corners of the respective glass substrates 1, for example, on the substrate outside the sealing layer 4, are planarized and protected. Since the film 7 is formed at the same time, there is no step in the position recognition mark 6 and no dust 80 or 90 such as rubbing cloth dust adheres even when the alignment treatment by rubbing is performed. Positioning can be easily performed.

〔Example〕

FIG. 1 is a diagram showing a method of an embodiment of the present invention.
Indicates a glass substrate 1a (for example, an upper substrate), FIG. 12B shows a state in which the glass substrate 1b (for example, a lower substrate) is aligned, and FIG. (A) is a top view of each, and (b) is a cross-sectional view of each.

In the figure, 6a and 6b are position recognition marks, for example, ITO (In)
₂ O ₃ —SnO ₂ ), and the sealing layer 5 on the glass substrates 1 a and 1 b
At least two of them are formed at appropriate positions on the outer side of the substrate, for example, at the corners on the diagonal line of the substrate, at the same time as the transparent electrodes in the form of stripes not shown here. Outer diameter is 0.2mm (6a)-0.1mm (6b)
It is about.

Reference numerals 7a and 7b denote flattening protective films, which are formed simultaneously with an alignment film (not shown), for example, a polyimide resin film, and have a circular shape with a size of, for example, 5 mmφ. The marks 6a and 6b are formed simultaneously with the alignment film by transfer printing, for example, so as to cover the marks 6a and 6b with a film having a thickness of about 100 nm.

As can be seen from the cross-sectional views of FIGS. 7A and 7B, the steps of the position recognition marks 6a and 6b are gently covered by the flattening protective films 7a and 7b. No dust or the like adheres to the position recognition mark itself. Therefore, the position recognition mark can be automatically aligned by the image recognition alignment device using the TV monitor while observing the transmitted light or the reflected light,
It is possible to achieve high precision and easily within a short period of time, so that the bonding accuracy of the substrate and the shaping and cutting accuracy of the substrate have been greatly improved as compared with the conventional example, and the working efficiency has been greatly improved.

FIG. 2 is a view showing a method of another embodiment of the present invention. FIGS. 2A and 2B show two modified examples.

5A, the flattening protective films 7'a, 7'b are not circular but are square, and in FIG. 4B, the position recognition marks 6'a, 6'b are circular instead of square. Use something. It is clear that any of the above satisfies the purpose of the method of the present invention and has the same effect as the above-mentioned embodiment.

The same parts as those described in the above drawings are denoted by the same reference numerals, and the description of the same parts will be omitted.

Further, the position recognition mark 6 is not limited to the above-mentioned shape, and it goes without saying that an easy-to-use mark such as a cross, a star, or a triangle may be used as appropriate.

Further, the position of the position recognition mark 6 is not limited to the corner of the substrate, but may be provided outside the display screen, that is, at an appropriate place outside the seal layer 5, and the number of the position recognition marks 6 may be at least two. If it is possible to align the two substrates and determine the position of each cutting line, it is needless to say that three or more substrates may be used if necessary.

The method of the embodiment described above is an example, and it is needless to say that materials and configurations to be used may be suitably used or a combination thereof may be used as long as the method of the present invention is followed.

〔The invention's effect〕

As described above, according to the method of the present invention, when forming the alignment film 3, for example,
Since at least two position recognition marks 6 provided at the corners of the substrate outside the seal layer 5 are simultaneously formed with the flattening protective film 7, there is no step in the position recognition marks 6. Even when the orientation treatment by rubbing is performed, dusts 80 and 90 such as fiber scraps of the rubbing cloth do not adhere.

Therefore, high-precision positioning can be easily performed within a short period of time, and the bonding accuracy of the substrate and the shaping and cutting accuracy of the substrate are greatly improved as compared with the conventional example, and the work efficiency is also greatly improved. This greatly contributes to improving the quality and yield of the liquid crystal display element and reducing the price.

[Brief description of the drawings]

1 is a diagram showing a method of an embodiment of the present invention, FIG. 2 is a diagram showing a method of another embodiment of the present invention, FIG. 3 is a diagram showing an example in which dust adheres to a conventional position recognition mark, FIG. 4 is a diagram showing a panel configuration of the liquid crystal display element. In the figure, 1 (1a, 1b) is a glass substrate, 2 (2a, 2b) is a transparent electrode, 3 (3a, 3b) is an alignment film, 4 is a spacer, 5 is a sealing layer, 6 (6a, 6b), 6 '(6'a, 6'b) is a position recognition mark, 7 (7a, 7b) and 7'(7'a,7'b) are flattening protective films, and 80 and 90 are dust.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02F 1/13 G02F 1/1333 G02F 1/1337

Claims (1)

(57) [Claims] 1. A liquid crystal display device comprising two glass substrates (1) opposed to each other with a gap-shaped space therebetween sealed with a sealing layer (5), and liquid crystal is injected and sealed into the gap-shaped space. In the manufacturing method, when forming the transparent electrode (2) on the glass substrate (1), a position recognition mark (6) is simultaneously formed on the substrate surface outside the sealing layer (5). A method for manufacturing a liquid crystal display element, wherein a flattening protective film (7) is simultaneously formed covering the position recognition mark (6) when forming 3).