JPS61173223A - Formation of liquid crystal display device - Google Patents

Abstract

PURPOSE:To maintain the specified distance between two electrodes by manufacturing spacers on a laminate having a preliminarily provided mask effect. CONSTITUTION:A polyimide soln. 15, for example, PIQ, is coated atop one side and UV light 20 is exposed through the substrate to the resin coating from the lower side of the substrate, then the laminate 50 thereof has light shieldability and therefore the other part except the upper resist can be removed. The PIQ under the resist as a mask is removed and thereafter the positive resist is removed. The liquid crystal filling part is at the same time removed at 3mm width in the peripheral part of the substrate and studs as sealants 6 are provided so as to enclose the inside of the other part. The disposition of the spacers here and there at substantially prescribed intervals therebetween is thus made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention relates to a liquid crystal display panel or an active or matrix type liquid crystal display panel, and relates to a liquid crystal display panel that is used to reduce the thickness of a display unit of a microcomputer, word processor, television, etc. This invention relates to a method for creating a display device.

``Conventional technology j'' Regarding conventional liquid crystal display devices, a transparent conductive film and an alignment film are provided inside two transparent substrates, and liquid crystal is filled between the two transparent substrates to determine whether or not a voltage is applied between the two electrodes. ``On'' and ``Off'' were controlled by This display displays characters, graphs, or pictures.

However, there is a thick gap of about 10 microns between these two transparent electrodes, and recently this gap has increased to 5 microns. However, such a wide interval is TN (Zwifte Tsuku Nematic)
However, if a ferroelectric liquid crystal (hereinafter referred to as FLC) using a chiral smectisocyanate C phase is used, a thickness of 2μ or less, generally 1±0.5μ, is required.

In addition, when a conventionally known TN liquid crystal is filled with a gap of 10 μm using surface tension, a spacer has been devised to control the gap. That is, spacers are generally spherical particles of organic resin, such as Micropearl SP.
-210 (average particle size 10.θ±0.5μ) is used. This microbar is a divinylbenzene-based crosslinked polymer and is a transparent true spherical fine particle.

That is, FIG. 1 shows a vertical cross-sectional view of a conventional liquid crystal display device. In the drawing, two transparent substrates (1
), (1') are filled with a sealing material (6) made of a mixture of resin and a spacer (7) to prevent the liquid crystal from leaking to the outside, and the distance between the two substrates is maintained at the periphery. It is kept constant. However, in the display section (10), that is, the area filled with the liquid crystal (5), the two transparent electrodes tend to short-circuit or come close to each other due to external mechanical stress on the transparent substrate or due to the flatness of the substrate. As a result, the liquid crystal loses its translucency or becomes partially black, which tends to cause defects. For this reason, other spacers (4) are also scattered around the liquid crystal section to keep the respective electrodes at a constant distance so as not to short-circuit.

These spacers are simply scattered between alignment films,
Point contact was made with each, and a large local load was applied to this contact area. If there is an active element in this contact area, this element may be destroyed.

``Problem to be solved by the invention J'' Furthermore, when trying to actually make a liquid crystal display device using this TN liquid crystal, after sealing the two substrates with a sealing material except for a part of the periphery, The liquid crystal is kept in a vacuum and filled with liquid crystal using capillary action.However, the gap between them is 2
In liquid crystals such as PLCs that require μ or less,
Because the viscosity of the spacer itself is high, the spacer may move when filling using capillary action, and because the spacer itself is small, it tends to aggregate with each other, making it impossible to disperse it uniformly. Ta.

Also, since the spacer and alignment film are not bonded in any way,
When the temperature of the display device rises after sealing, the substrate tends to swell due to thermal expansion of the liquid crystal itself, making it impossible to maintain a constant distance between the two electrodes.

For this reason, a phenomenon has been observed in which the contrast of the display differs between the center and the periphery. Especially if the display device is 20
Defects were more likely to occur when the panels were large (cm x 30 cm). Furthermore, since the spacers are scattered at different positions, in a display in which active elements are connected, a local point center force may be applied to the elements, which is likely to cause element failure.

``Means for Solving the Problem J'' For this reason, the present invention does not use the conventionally known single spacer, but instead sets one substrate side provided with a laminate having a masking function at a predetermined height. The substrate is covered with an organic resin film such as polyimide resin using a coating method, and then light is irradiated from the back side of the substrate to selectively form "scallop"-shaped spacers at predetermined positions without using a mask. Furthermore, the sealing material in the peripheral area is also formed of the same material at the same time.For this reason, a positive resist is especially used on the polyimide resin to be applied, and the resist is applied to the areas other than the upper part of the laminate.・By etching and removing the cysts and then removing the polyimide resin, we were able to form spacers in roughly the same shape above the laminate.In this way, we were able to form spacers and seals without using any new masks. It has become possible to create materials.

Of course, if the organic resin film for the spacer, such as polyimide resin, has positive photosensitivity, the positive photosensitive polyimide resin is coated by a coating method without using a positive resist, and then the laminate is used as a mask and irradiated with ultraviolet light.
A spacer can be created by removing the polyimide resin which has a masking effect and is not located above the laminate without using any mask.

"Function" By doing so, it became possible to create a spacer on a previously provided laminate having a masking effect without using any new mask. In addition, the laminated body having this masking effect is, for example, a laminated body of a non-single crystal semiconductor having an NIN structure and a pair of electrodes thereunder, or an M
A J-type element made of a laminate having a TM (metal-insulator-metal) structure is common.

In this way, the height of the organic resin that acts as a spacer can be achieved by using the same material as the sealing material in the peripheral area and the spacer in the display area, and the same coating film can be selectively left even with variations in height. Therefore, we were able to obtain an accuracy of ±0.2μ or less. In addition, this sealing material and a spacer are used to bring the substrate into close contact with the inner surface of another opposing light-transmitting substrate. Therefore, even if the two substrates initially have some degree of non-flatness due to the undulation-like unevenness of the substrates themselves, it can be made uniform by the size and height of the sealing material and the spacer. That is, after forming the seal portion and the spacer portion in the shape of a “scallop” using polyimide resin, another substrate having semi-hard translucent properties is placed above it in a vacuum, and heated to bring them into close contact. Then, due to the sealing part and the spacer part being in close contact with each other, even if the vacuum is removed afterwards, the respective substrates are substantially in close contact with each other, so they do not return to their original non-flat state and the gap between the electrodes remains constant. Therefore, in the final state, problems such as part of the panel being too wide do not occur. In addition, because the substrates are brought into close contact with each other using spacers, the mechanical strength of the display panel itself is not as strong as that of only one panel, but is similar to that of laminated glass, making it possible to have a mechanical strength that is essentially equivalent to the strength of two panels. It became.

The present invention will be described below according to Examples.

Example 1 FIG. 2 shows a vertical cross-sectional view showing the liquid crystal display device of the present invention and its manufacturing process.

In Figure 2 (A), two transparent substrates, for example glass substrates (1) and (1''), one is a solid glass substrate (
1).

On the other hand, a semi-hard glass plate or a translucent organic resin substrate (1°) was used that could be bent when the gap was evacuated.

One side of this hard substrate (1) is connected to the lower leads (11
), a non-single-crystal semiconductor non-linear element with an NIN junction (
12), a laminate (5) consisting of an upper chromium electrode (13)
0). A translucent interlayer insulator (8) is provided around the laminate 50). A transparent conductive film (2), an alignment treatment or an alignment film (3) is provided on the laminate of the lower substrate (1), and an upper electrode (13) of the transparent conductive film (2) and the laminate (50). are electrically connected in series.

Although it is only shown in Figure 2 (C), a similar transparent conductive film (2") can be applied to a semi-hard substrate (1").
, orientation treatment (3') was performed.

Next, as shown in FIG. 3(A), a polyimide solution (15) such as PIQ is applied to the upper surface of one side using a spinner, a roll coater, a spray method, or a free-line printing method.

Furthermore, a positive photoresist (not shown in the drawing) is applied thereon.

Next, these are exposed to ultraviolet light (20) from below the substrate through this substrate (10 mW/cm2 light for about 60 seconds).
did. Then, since this laminate (50) has a light-shielding property, only the resist above it can be left and the other parts can be removed. Using this resist as a mask, the PTQ underneath was removed. Thereafter, the positive resist was removed to obtain the image shown in FIG. 2(B).

At the same time, a "scallop" as a sealing material (6) was provided at the periphery of the substrate with a length of 113 mm, excluding the liquid crystal filling part and surrounding the other parts. That is, it becomes possible to arrange the spacers in a scattered manner with substantially predetermined intervals between the spacers. Furthermore, by creating a "scallop" using this mask method, in the case of an active type liquid crystal panel, localized mechanical stress is applied to nonlinear elements or switching elements, causing leads to break or the elements to become inoperable. possibility can be avoided.

Furthermore, in order to further complete the method of the present invention, FIG.
As shown in the figure, a semi-hard opposing light-transmitting substrate (1') having a light-transmitting electrode (2') and an alignment film (3') provided thereon were pressed together and the gap was evacuated at the same time. In this state, post-hake was performed at 200-300'c.

Then, the scallops (6) and (14) came into close contact with the polyimide alignment film of the opposing glass, making it possible to glue the two glasses together.

After this postbake, the height was 2μ or less, in this case 1.2μ±0.2μ, which was the preferred spacing for the FLC.

In this case, if the opposing glass or translucent organic resin is semi-hard, the other translucent substrate (1) should be aligned along the distortion of the glass (1) itself, and the spacer Since they are fixed to each other, even if the glass substrates themselves have distortions (smooth irregularities), the opposing glasses can be substantially bonded to each other by keeping the electrode gap constant regardless of the distortion.

In the embodiment of the present invention, the gap held by the spacer was then filled with ferroelectric liquid crystal (5) by a known method.

As described above, in order to make the gap between two opposing electrodes constant, one polyimide resin film is selectively left and the same upper and lower polyimide alignment films are used as a spacer and a sealing material. and are placed in close contact with each other. And it was manufactured without using any new masks. As a result, the distance between the two alignment films could be kept constant within a predetermined thickness of 2μ or less within a range of ±0.5μ. In particular, it has an active matrix structure and the number of dots is 400 x 1920.
In a liquid crystal panel with a large area of 30 cm, it was possible to prevent the central part from expanding more than necessary or the two electrodes from coming close to each other.

For this reason, in the past, when attempting to manufacture a liquid crystal display device using large-area substrates, each substrate had to be polished extremely precisely, and the sealant and spacer were made of completely different materials. . In addition, the spacers were not in close contact with the inner surfaces of the upper and lower substrates. Furthermore, the position of the spacer could not be estimated. However, the present invention has other features such as not requiring an expensive polishing process that is 2 to 5 times the price of the glass substrate, and simplifying the process of sealing with a sealing material and the process of dispersing spacers into one. have

In addition, since one to several spacers (one spacer in the example) are provided at a distance of approximately 400 μm, the liquid crystal panel can be handled as an extremely strong substrate similar to so-called laminated glass.

The shape of the spacer can be made into surface contact rather than point contact with the substrate surface, and its area can also be freely controlled.

In the present invention, the alignment film may be left on the glass substrate in the sealing material portion at the periphery of the glass substrate, or may be removed.

In the present invention, a polyimide solution was used. However, this polyimide may be used to form a sealing material by using an ultraviolet curable polyimide (positive) resin and spacing by a selective etching method. However, such positive-type polyimide resins are not commercially available and are still in the experimental stage, so the resist coating process can be omitted at present, but they are expensive.

In the present invention, the same main component material is used for the "scallop" and the alignment films above and below it. This is because all the materials are made of polyimide to improve their adhesion to each other.

However, other materials may be used if this adhesiveness is guaranteed.

[Brief explanation of drawings]

FIG. 1 shows a longitudinal sectional view of a conventionally known liquid crystal display device. FIG. 2 shows a longitudinal sectional view showing the manufacturing process of the liquid crystal display device of the present invention.

Claims (1)

[Claims] 1. A step of forming a laminate having a masking effect and a transparent electrode on a transparent substrate, a step of forming an organic resin film on these, and a step of forming a positive photoresist on the resin film. A step of forming a film, irradiating light from the back side of the substrate, leaving the resist above the layered structure having a masking effect and removing it, and then selectively covering the organic resin film using the remaining resist as a mask. A method for manufacturing a liquid crystal display device, characterized in that the remaining film is used as a spacer. 2. A step of forming a laminate having a masking effect and a transparent electrode on a transparent substrate, a step of forming a positive photosensitive organic resin film on these, and a step of irradiating light from the back side of the substrate. . A method for manufacturing a liquid crystal display device, characterized in that the organic resin film is selectively removed above the laminate having a masking effect, and the remaining film is used as a spacer. 3. A method for manufacturing a liquid crystal display device according to claim 1 or 2, wherein the film having a masking effect is an active element connected to each pixel of a liquid crystal display panel using an active matrix method.