JP4561066B2 - Liquid crystal display panel and manufacturing method thereof - Google Patents

Description

  The present invention relates to a liquid crystal display panel and a method for manufacturing the same, and more particularly, to a liquid crystal display panel and a method for manufacturing the liquid crystal display panel that can reduce the size of the liquid crystal display panel by reducing the seal width of the seal portion at the periphery of the panel.

A liquid crystal display panel (LCD panel) is configured by enclosing a liquid crystal material between two substrates (a pair of substrates) arranged to face each other with a liquid crystal interposed therebetween. The gap between the two substrates (substrate interval) is one of the important factors that influence the optical characteristics such as transmittance, contrast, viewing angle, and afterimage of the liquid crystal display panel. It is necessary to prevent the gap from becoming uneven.
Therefore, as a method for keeping the substrate interval constant, a method in which a spacer (gap material) is interposed between the substrates is conventionally used.
More specifically, for example, in a region corresponding to an effective pixel portion (inside the display region) of a liquid crystal display panel, a fine gap material such as glass beads or fibers is scattered at a predetermined density between two substrates. Method is used. In recent years, a method of providing an on-chip spacer (OCS) in which a convex portion (island portion) such as a photosensitive resin is formed by patterning on a pixel light-shielding portion on the substrate surface using photolithography or an etching technique is also used. (For example, see Patent Document 1)

In addition, in the non-effective pixel portion (outside of the display area) at the periphery of the liquid crystal display panel, two substrates are bonded and sealed using a sealing resin mixed with fiber as a gap material, and the interval is kept constant. The holding method is widely used.
Specific examples are shown in FIGS. FIG. 5 is a plan view showing the configuration of the liquid crystal display panel, and FIG. 6 is a cross-sectional view showing the configuration of the seal portion in the region b of FIG.
As shown in FIG. 6, in the sealing part, a fiber (gap material) for adjusting the height is mixed in a sealing adhesive resin (sealing material), sandwiched between liquid crystal panels, and an appropriate pressure is applied. Two substrates are bonded. That is, the seal portion simultaneously bonds the two substrates, secures the gap, and seals the liquid crystal. (For example, see Patent Document 2)

JP 2002-131755 A JP 2000-310784 A

  However, in the conventional sealing part bonding method described above, the controllability of the sealing part is low due to the elasticity of the resin and the like, and the position and shape of the boundary of the sealing part cannot be clearly controlled. That is, the peripheral edge (side surface) of the seal portion has a wavy and irregular shape both in a plane parallel to the substrate as shown in FIG. 5 and in a plane perpendicular to the substrate as shown in FIG. Therefore, it was not possible to accurately define the predetermined position with a linear shape. As a result, it is necessary to secure a wide area as a region for the seal portion outside the effective pixel portion in consideration of a variation in the position of the peripheral edge of the seal portion, which increases the size of the liquid crystal display panel. It was.

Moreover, in order to cope with the deformation of the seal itself, there is a problem that the width of the seal portion must be widened.
In particular, in an LCD panel for EVF (Electric View Finder) and the like, the size of the entire panel affects the downsizing of the set, so the size of the area other than the effective pixels of the panel is important, and the ineffective pixel region There was a request to narrow the width.
Further, the method of mixing the fiber for adjusting the height with the seal member has a problem that it is necessary to optimize the size and material of the fiber, and it is difficult to control and takes time.

  The present invention has been made in view of such problems, and its purpose is to form a narrow width by controlling the seal width of the seal portion with high accuracy, thereby reducing the size of the panel. An object of the present invention is to provide a liquid crystal display panel that can be manufactured and a method for manufacturing the same.

In order to solve the above problems, a liquid crystal display panel of the present invention includes a TFT array substrate and a counter substrate disposed to face the TFT array substrate. And it has the effective pixel part provided on the TFT array substrate, and the non-effective pixel part provided around the effective pixel part. Further, between the TFT array substrate and the counter substrate, an on-chip spacer provided in the effective pixel portion and between the TFT array substrate and the counter substrate so that the non-effective pixel portion surrounds the effective pixel portion. The sealing part which consists of the resin part currently formed and the sealing material is provided. Further, in the same photolithography patterning process, the on-chip spacer and the resin portion are formed of the same resin material such as photosensitive polyimide resin or photosensitive novolac resin , and the sealing material formed on the counter substrate side. The resin part and the counter substrate are connected.

As a preferred example, a sealing material is formed on the outer side surface of the seal portion between the TFT array substrate and the counter substrate.

As a preferred example, the apparatus further includes an on-chip spacer that maintains the predetermined distance between the pair of substrates formed inside the display area, and the seal portion and the on-chip spacer are formed of the same material. It is characterized by being.
As another preferred example, an on-chip spacer for maintaining a predetermined distance between the pair of substrates is not formed inside the display region.
Preferably, the seal portion functions as a spacer for maintaining the predetermined distance between the pair of substrates.
Further preferably, the seal part is formed to have a width of 200 μm to 1000 μm.

In addition, the method for manufacturing a liquid crystal display panel according to the present invention includes a photosensitive polyimide resin or a photosensitive resin for an effective pixel portion provided on a TFT array substrate and an ineffective pixel portion provided around the effective pixel portion . And a photomask in which an on-chip spacer provided in the effective pixel portion and a seal portion pattern formed so as to surround the effective pixel portion in the non-effective pixel portion are formed. And a step of transferring the pattern to the resin material. Then, by developing the resin material is applied and forming a resin portion of the seal portion to the on-chip spacer and non-effective pixel portion in the effective pixel portion, on the top surface of the fat portion of the sealing portion, the sealing material step And a step of bringing the counter substrate into close contact with the TFT array substrate. In addition, the liquid crystal material is sealed in a space surrounded by the TFT array substrate, the counter substrate, and the seal portion.

According to the present invention, it is possible to provide a liquid crystal display panel which can be formed with a narrow width by controlling the seal width of the seal portion with high accuracy, and thereby the panel can be miniaturized, and a method for manufacturing the same. .
The present invention can also be applied to a relatively large liquid crystal display panel. In that case, the display area in the liquid crystal display panel can be expanded.

Hereinafter, the present invention will be described with reference to FIGS.
1 is a plan view of a liquid crystal display panel according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the liquid crystal display panel, and FIG. 2A is a cross-sectional view in a region a of FIG. FIG. 2B is a cross-sectional view showing the configuration of the spacer inside the effective pixel portion, FIG. 3 is a flowchart for explaining the manufacturing method of the liquid crystal display panel of this embodiment, and FIG. It is a figure which shows the structure of the liquid crystal display panel of other embodiment.
Note that the liquid crystal display panel shown in the present embodiment is a small liquid crystal display panel for an EVF (Electric View Finder) having an effective pixel area size of about 0.24 inch (about 6.1 mm).

As shown in FIG. 1, a liquid crystal display panel 100 includes an effective pixel portion 101 used for actual image display, a non-effective pixel portion 102 at the periphery thereof, and a pad portion 103 in which external connection terminals (pads) 104 are formed. Have
As shown in FIGS. 2A and 2B, the effective pixel portion 101 and the non-effective pixel portion 102 are configured by disposing the TFT array substrate 110 and the counter substrate 120 to face each other at a predetermined interval.

  In the area corresponding to the effective pixel portion 101 shown in FIG. 1 on the upper surface of the TFT array substrate 110 (the surface facing the counter substrate 120), a large number of pixel electrodes (not shown) having the same shape are formed in a grid pattern. The The pixel electrodes are connected to scanning lines and signal lines (not shown) through TFTs made of amorphous silicon, polysilicon, or the like. An alignment film is laminated on the pixel electrode with a protective film interposed therebetween.

  Further, an on-chip spacer (OCS) 141 as a gap material shown in FIG. 2B is formed in this region (a region corresponding to the effective pixel portion 101 on the upper surface of the TFT array substrate 110). The OCS 141 has a trapezoidal cross section as shown in the figure by a lithography process, a development / etching process, and the like, and is formed at a height that defines the interval between the TFT array substrate 110 and the counter substrate 120. Thereby, in the effective pixel portion 101, the interval between the TFT array substrate 110 and the counter substrate 120 is maintained at a predetermined interval.

In the liquid crystal display panel 100 of the present embodiment, the width W2 of the OCS 141 is 2 μm to 3 μm, and the height is 2.7 ± 0.5 μm.
Further, OCS is polyimide resin, is formed by a photosensitive resin such as a novolac resin. The OCS 141 of this embodiment is formed of a novolac resin.

As shown in FIG. 1, a resin portion 131 is formed in the non-effective pixel portion 102 on the upper surface of the TFT array substrate 110 so as to surround the effective pixel portion 101.
The resin part 131 is formed using the same resin material by the same lithography process and development / etching process as the OCS 141 described above. Further, as shown in FIG. 2A, it has a trapezoidal cross section, and is formed so that its height substantially defines a distance between the TFT array substrate 110 and the counter substrate 120. That is, the resin part 131 itself is formed to act as a kind of spacer. Thereby, in the ineffective pixel portion 102, the distance between the TFT array substrate 110 and the counter substrate 120 is maintained at a predetermined distance.

  Further, as shown in FIG. 2A, an extremely thin sealing material 132 is affixed to the top surface of the resin portion 131, whereby the counter substrate 120 is joined to the resin portion 131. That is, it is bonded to the TFT array substrate 110. The sealing material 132 is made of an adhesive or the like.

In the present embodiment, the width W1 of the resin portion 131 is 200 μm to 1000 μm. Preferably, the width W1 of the resin portion 131 is 300 μm to 700 μm. The height of the resin part 131 is 2.7 ± 0.5 μm, which is the same as the height of the OCS 141. Strictly speaking, the height of the resin portion 131 should be set so that the total height of the thickness of the sealing material 132 and the thickness (height) of the resin portion 131 is the same as the height of the OCS 141. . However, since the sealing material 132 is affixed very thinly, it can be considered that the height of the resin portion 131 is substantially the same as the height of the OCS 141.
Resin portion 131 of this embodiment, polyimide resin is formed by photosensitive resin such as a novolac resin. The resin part 131 of the present embodiment is formed of a novolac resin similarly to the OCS 141.

  The counter substrate 120 is a transparent substrate having a size including the effective pixel portion 101 and the non-effective pixel portion 102 shown in FIG. 1, and is bonded to the resin portion 131 formed on the TFT array substrate 110 via the seal material 132. Is done. A transparent common electrode and an alignment film (not shown) are sequentially stacked on the lower surface of the counter substrate 120 (the surface facing the TFT array substrate 110).

In the liquid crystal display panel 100, liquid crystal is injected into a space surrounded by the TFT array substrate 110, the counter substrate 120, and the seal portion 130 formed as described above.
In addition, a polarizer or the like (not shown) is provided outside the TFT array substrate 110 and the counter substrate 120 to constitute the liquid crystal display panel 100.

Next, a method for manufacturing the liquid crystal display panel 100 will be described with reference to the flowchart of FIG.
First, a spacer material, which is also a photoresist material such as a novolak resin, is applied on the TFT array substrate 110 on which the pixel electrode is formed to a thickness of 2.7 μm by spin coating (step S11).

Next, the TFT array substrate 110 is exposed by irradiating, for example, ultraviolet rays using a photomask in which a pattern of a region for forming the OCS is formed, and an image of the OCS pattern is transferred to the TFT array substrate 110 (step) S12). In this embodiment, at this time, images of these spacer patterns are collectively transferred onto the TFT array substrate 110 using a mask on which both the resin part 131 and the OCS 141 are formed.
Next, the TFT array substrate 110 is developed and etched to form the resin part 131 and the OCS 141 on the TFT array substrate 110 (step S13).

On the other hand, a common electrode is separately formed on one surface of the counter substrate 120.
Then, an alignment film is formed on the opposing surfaces of the TFT array substrate 110 and the counter substrate 120, for example, by vapor deposition (step S14).
Next, the sealing material 132 is applied to the top surface of the resin portion 131 formed on the TFT array substrate 110 (step S15).
After the sealing material 132 is applied, the TFT array substrate 110 and the counter substrate 120 are overlapped, and an appropriate pressure is applied to bring them into close contact with each other (step S16).

When the TFT array substrate 110 and the counter substrate 120 are bonded, a liquid crystal material is sealed in a space surrounded by these substrates and the seal portion 130 (step S17).
After the liquid crystal material is sealed, the liquid crystal sealing port is cured with an ultraviolet curable resin or the like and sealed (step S18).
In this way, the basic components of the liquid crystal display panel are manufactured.

As described above, according to the liquid crystal display panel 100 of the present embodiment, the seal portion 130 of the panel peripheral portion (ineffective pixel portion 102) is formed by OCS, and this OCS serves both as gap control and liquid crystal sealing. I am doing so. Therefore, the accuracy of the seal width and the gap can be remarkably improved as compared with the conventional case. That is, the resin portion 131 is formed using a lithography process and a development / etching process. Therefore, the width, position, etc. of the seal portion 130 can be controlled with lithography accuracy. That is, the width, position, etc. of the seal portion 130 are set to 0. It can be controlled with an accuracy of about several μm.
As a result, the seal portion 130 can be formed in the ineffective pixel portion 102 with an appropriate width necessary and sufficient for enclosing the liquid crystal and maintaining the substrate interval, that is, with a narrower width than the conventional one.

As a result, it is not necessary to secure a margin in the ineffective pixel portion 102, and the width of the ineffective pixel portion 102 can be reduced.
Specifically, as shown in FIG. 1, a conventional liquid crystal display panel having a size indicated by a broken line can be downsized to a size as shown by a solid line without changing the size of the effective pixel portion 101. Therefore, if the size of the panel is not changed, the size of the effective pixel portion 101 can be increased.

In the present embodiment, the resin part 131 and the OCS 141 are collectively formed by a lithography process. Therefore, the manufacturing process can be simplified. As a result, a liquid crystal display panel can be manufactured at a low cost and in a short period.
Thus, by reducing the seal width, the panel size can be reduced, and the apparatus and the set can be reduced in size and cost.

In addition, this invention is not limited to embodiment mentioned above, You may modify | change variously within the scope of the present invention.
For example, when the panel size is small, the OCS in the display region may not be provided as long as the seal portion 130 supports the distance between the TFT array substrate 110 and the counter substrate 120 with sufficient strength. Specifically, for example, if the size (diagonal line size) is 1 inch (2.54 mm) or less, the OCS in the display area can be removed. With such a configuration, when the alignment film is formed on the TFT array substrate, a region that becomes a shadow of the OCS does not occur. Therefore, the alignment film can be formed uniformly on the entire surface, which is effective.

  Further, the size of the resin portion 131 may be arbitrarily set according to the size of the liquid crystal display panel. The OSC can be formed with a width of about 2 μm. Therefore, as long as the width of the resin portion 131 is 2 μm or more, it may be formed with an arbitrary width.

  Further, in this embodiment, as shown in FIG. 2A, the sealing material 132 is pasted on the top of the resin portion 131 and the resin portion 131 and the counter substrate 120 are joined. For example, as shown in FIG. As described above, the sealing material 133 may be attached to the outer side surface of the resin portion 131 so that the TFT array substrate 110 and the counter substrate 120 are bonded to each other. By doing so, the interval between the TFT array substrate 110 and the counter substrate 120 can be controlled with high accuracy, which is effective.

  In addition, the liquid crystal display panel of the present invention is not limited to EVF use, and can be applied to any display panel for projectors, portable devices, and the like.

FIG. 1 is a plan view showing a configuration of a liquid crystal display panel according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the liquid crystal display panel shown in FIG. FIG. 3 is a flowchart showing a manufacturing method of the liquid crystal display panel shown in FIG. FIG. 4 is a diagram showing a configuration of a liquid crystal display panel according to another embodiment of the present invention. FIG. 5 is a plan view showing a configuration of a conventional liquid crystal display panel. FIG. 6 is a cross-sectional view showing a configuration of a conventional liquid crystal display panel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Liquid crystal display panel, 101 ... Effective pixel part, 102 ... Ineffective pixel part, 103 ... Pad part, 110 ... TFT array substrate, 120 ... Opposite substrate, 130 ... Seal part, 131 ... Resin part, 132, 133 ... Seal 141, on-chip spacer (OCS)

Claims (3)

A TFT array substrate;
A counter substrate disposed opposite to the TFT array substrate;
An effective pixel portion provided on the TFT array substrate;
A non-effective pixel portion provided around the effective pixel portion;
On-chip spacers provided in the effective pixel portion between the TFT array substrate and the counter substrate;
Between the TFT array substrate and the counter substrate, the non-effective pixel portion is provided with a seal portion formed of a resin portion and a sealing material formed so as to surround the effective pixel portion,
In the same photolithography patterning process, the on-chip spacer and the resin portion are formed of the same resin material made of photosensitive polyimide resin or photosensitive novolac resin ,
The liquid crystal display panel, wherein the resin portion and the counter substrate are connected by the sealing material formed on the counter substrate side.   The liquid crystal display panel according to claim 1, wherein a sealing material is formed on an outer side surface of the seal portion between the TFT array substrate and the counter substrate. Applying a resin material made of photosensitive polyimide resin or photosensitive novolac resin to the effective pixel portion provided on the TFT array substrate and the non-effective pixel portion provided around the effective pixel portion ; ,
Using an on-chip spacer provided in the effective pixel portion and a photomask in which a pattern of a seal portion formed so as to surround the effective pixel portion is formed in the non-effective pixel portion, the pattern is applied to the resin material. A transfer process;
By developing the resin material, and forming a resin portion of the seal portion on the on-chip spacers and the non-effective pixel portion to the effective pixel portion,
Applying a sealing material to the top surface of the oil portion of the seal portion;
A step of overlapping and adhering a counter substrate to the TFT array substrate;
And a step of enclosing a liquid crystal material in a space surrounded by the TFT array substrate, the counter substrate, and the seal portion.

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