JP2008145755A - Method of manufacturing liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a liquid crystal display panel, which suppresses generation of air bubbles in a liquid crystal layer. <P>SOLUTION: With respect to a liquid crystal display panel 1 where air bubbles has been generated when being lit in a state of a low temperature of ≤10°C, spacers 11 are contracted by applying a prescribed pressure between an array substrate 5 and a counter substrate 6 in such state of a low temperature that the volume of a liquid crystal layer 7 is reduced. Since the volume between the array substrate 5 and the counter substrate 6 can be reduced as much as the volume of air bubbles generated at the low temperature, the generation of air bubbles in the liquid crystal layer 7 can be suppressed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a liquid crystal display element including a liquid crystal layer that is made of a liquid crystal material and interposed between a pair of substrates.

  Conventionally, a liquid crystal display panel as this type of liquid crystal display element has an array substrate and a counter substrate arranged to face each other via a spacer, and a liquid crystal layer made of a liquid crystal material is interposed between the substrates. The array substrate and the counter substrate are bonded to each other by a sealing material.

  A manufacturing method of such a liquid crystal display panel includes a sealing material application step of applying a sealing material to at least one of the array substrate and the counter substrate, and a liquid crystal in which a predetermined amount of liquid crystal material is dropped into the seal. A dropping step, a vacuum bonding step of bonding the array substrate and the counter substrate in a vacuum state, and a sealing material curing step of curing the sealing material.

  In such a liquid crystal display panel manufacturing method, the amount of liquid crystal to be dropped needs to be controlled with high precision. If the amount of liquid crystal is small, bubbles are generated, and if the amount of liquid crystal is excessive, the distance between substrates, that is, the gap is not uniform. There is a problem that uneven display occurs.

As a method for manufacturing a liquid crystal display panel for preventing the bubbles, a contact hole in which liquid crystal is difficult to enter is filled with a column layer to prevent bubbles from remaining in the contact holes (see, for example, Patent Document 1). Alternatively, there is known a technique in which the bubbles in the liquid crystal are expelled to the outside by sequentially bonding the substrates from the center side to the peripheral side (see, for example, Patent Document 2).
JP 2004-295016 A JP 2004-212444 A

  Conventionally, when inspecting a liquid crystal display panel, the liquid crystal display panel is inspected for lighting in a room temperature state, the display state is confirmed, and a defect is determined. With such an inspection method, display unevenness can be determined when the amount of liquid crystal is excessive, but determination when the amount of liquid crystal is insufficient is not easy.

  In particular, if the amount of liquid crystal is excessively insufficient, it can be easily recognized as the generation of bubbles, but if the amount of liquid crystal is only slightly insufficient, the elasticity of the spacer causes a problem in display at room temperature. Is not easy to recognize.

  In such a case, when the liquid crystal display panel is brought into a low-temperature state, the liquid crystal volume is insufficient due to the volume shrinkage of the liquid crystal and the volume of the liquid crystal display panel defined by the spacers supporting the substrates, so that no liquid crystal exists. Cold bubbles may be generated.

  And it has the problem that it is not easy to cope with such a low temperature bubble by the manufacturing method of the said conventional liquid crystal display element.

  The present invention has been made in view of these points, and an object of the present invention is to provide a method of manufacturing a liquid crystal display element in which the generation of bubbles in the liquid crystal layer is suppressed.

  The present invention includes a pair of substrates disposed to face each other, a liquid crystal layer made of a liquid crystal material and interposed between the pair of substrates, and a spacer that is positioned between the substrates and maintains a distance between the substrates. A manufacturing method of a liquid crystal display device comprising: a low temperature lighting inspection process for lighting the liquid crystal display element in a low temperature state of 10 ° C. or less, and bubbles are generated in the liquid crystal layer in the low temperature lighting inspection process. And a bubble removing step of shrinking the spacer by applying a predetermined pressure between the substrates in the low temperature state.

  For the liquid crystal display element in which bubbles are generated when lighted in a low temperature state of 10 ° C. or lower, the spacer is contracted by applying a predetermined pressure between the substrates in this low temperature state in which the liquid crystal layer contracts in volume.

  According to the present invention, since the volume between the substrates can be reduced by the volume of bubbles generated at low temperatures, the generation of bubbles in the liquid crystal layer can be suppressed even at low temperatures.

  Hereinafter, a configuration of a liquid crystal display element according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows an active matrix type liquid crystal display panel 1 as a liquid crystal display element. The liquid crystal display panel 1 includes an array substrate 5 as a substantially square plate-like substrate and a counter substrate 6 as a substantially square plate-like substrate. Are arranged opposite to each other, a liquid crystal layer 7 made of a liquid crystal material LC is interposed in a predetermined gap between the array substrate 5 and the counter substrate 6, and the outer peripheral edge of the array substrate 5 and the counter substrate 6 is sealed. The pixels 8 are joined by the member 8 and have pixels (not shown) arranged in a matrix.

  The array substrate 5 has a glass substrate 9 as an insulating substrate having a substantially transparent rectangular flat plate-like translucency. On the glass substrate 9, a switching element such as a thin film transistor for controlling the operation of each pixel is provided. The driving circuit for driving the switching elements, various array wirings for electrically connecting the driving circuits and the switching elements, and the distance between the array substrate 5 and the counter substrate 6 are formed in a matrix. A plurality of columnar spacers 11 to be held are provided.

  The counter substrate 6 is a substrate on which, for example, a color filter layer corresponding to each pixel is formed, and includes a square flat glass substrate 13.

  The glass substrates 9 and 13 are formed by dividing the large glass substrates 15 and 16 (FIG. 2), which are mother substrates, into predetermined sizes.

  The liquid crystal layer 7 is sandwiched between the substrates 5 and 6, surrounded by the seal member 8, and held between the substrates 5 and 6.

  The seal member 8 is a photo-curing seal such as an ultraviolet curable resin, and is formed in an endless substantially square frame shape around the liquid crystal layer 7.

  Next, a method for manufacturing the liquid crystal display element of the above embodiment will be described.

  First, various circuits, spacers 11 and the like are formed at predetermined positions on the large glass substrate 15 (circuit formation step).

  Next, as shown in FIGS. 2 and 3, the sealing material 8 is applied so as to surround the circuits and the spacers 11 (sealing material application process).

  Further, in this state, a predetermined amount of the liquid crystal material LC is dropped on the large-sized glass substrate 15 by a dropping means such as a syringe (not shown) on the inner region surrounded by the sealing material 8 (liquid crystal dropping step).

  Further, as shown in FIG. 4, the large-sized glass substrate 16 is bonded to the large-sized glass substrate 15 that has undergone the liquid crystal dropping process (bonding process) inside a vacuum chamber (not shown).

  In this state, the sealing material 8 is cured by irradiating the sealing material 8 with ultraviolet rays (not shown) or the like (sealing material curing step).

  Thereafter, the large-sized glass substrates 15 and 16 are divided along predetermined scribe lines (not shown), thereby obtaining the liquid crystal display panel 1 (division step).

  As shown in FIG. 5, such a liquid crystal display panel 1 is lit at a predetermined low temperature when the room temperature is considered to be about 25 ° C., specifically, at a low temperature of 10 ° C. or less, and the display state is changed. At the same time, a predetermined impact or vibration is applied under this low temperature condition to inspect the generation of bubbles B (low temperature lighting inspection process).

  Here, the dropping amount of the liquid crystal material LC in the liquid crystal dropping step is determined by the design of the liquid crystal display panel 1 and is determined by the size of the liquid crystal display panel 1 and the distance between the substrates 5 and 6, that is, the height of the spacer 11. However, the accuracy of the dropping amount of the liquid crystal material LC has an error of ± 5%, so that the liquid crystal material LC is excessive or insufficient.

  Therefore, the liquid crystal display panel 1 in which the dripping amount of the liquid crystal material LC is excessive with respect to the volume of the liquid crystal display panel 1 is lit at room temperature because the excess liquid crystal material LC is unevenly distributed in the panel and causes display unevenness. In the inspection process, the liquid crystal display panel 1 is judged to be defective, and the amount of the liquid crystal material LC dripped is insufficient with respect to the volume of the liquid crystal display panel 1. While the volume of the liquid crystal layer 7 shrinks in the lower lighting inspection process, the volume of the liquid crystal display panel 1 does not change, so that bubbles (cold bubbles) B are generated.

At this time, with respect to the liquid crystal display panel 1 in which the bubbles B are generated, a predetermined pressure, for example, a pressure P of ² kg / cm ² is applied between the substrates 5 and 6 by a pressure press device (not shown) or the like. The volume is reduced by pushing and shrinking the spacer 11 for a minute, and the bubble B is removed as shown in FIG. 6 (bubble removal step).

  Thus, according to the above-described embodiment, for the liquid crystal display panel 1 in which bubbles are generated when turned on in a low temperature state of 10 ° C. or lower, the substrate in this low temperature state in which the liquid crystal layer 7 shrinks in volume. By contracting the spacer 11 by applying a predetermined pressure P between 5 and 6, the volume between the substrates 5 and 6 can be reduced by the volume of the bubbles generated at a low temperature, so that the bubbles B in the liquid crystal layer 7 Generation can be suppressed and yield can be improved.

  That is, the spacer 11 that defines the volume of the liquid crystal display panel 1 cannot be effectively contracted due to the influence of the liquid crystal layer 7 filled between the substrates 5 and 6 at room temperature, whereas the liquid crystal layer 7 In a low temperature state where the volume shrinks, the spacer 11 can be crushed effectively, and the liquid crystal display panel 1 in which bubbles B are generated even when the liquid crystal material LC is dropped in a small amount when the liquid crystal display panel 1 is manufactured. Can be improved.

  In addition, the liquid crystal display panel 1 can detect the deficiency of the liquid crystal material LC due to the generation of bubbles even at room temperature such as room temperature when the drip amount of the liquid crystal material LC is excessively insufficient. If the amount of dripping material LC is a little short, even if a lighting test is performed at room temperature, the elasticity of the spacer 11 is unlikely to cause display problems, and this lack of dripping amount of liquid crystal material LC should be detected. Is not easy. For this reason, since the liquid crystal display panel 1 is inspected at low temperatures in the low temperature lighting inspection process, bubbles B are generated even when the amount of liquid crystal material LC dripped is slightly short. A slight deficiency in the amount of dripping can be reliably detected.

  Further, in the low temperature lighting inspection process, a predetermined impact or vibration is given to the liquid crystal display panel 1, so that the difference between the drip amount of the liquid crystal material LC and the volume of the liquid crystal display panel 1 becomes a bubble B more. This makes it easier to detect a deficiency in the amount of liquid crystal material LC dropped more reliably.

Then, by setting the pressure P applied between the substrates 5 and 6 to 2 kg / cm ² in the bubble removing step, the spacer 11 is set to double the pressure of 1 kg / cm ² that is normally applied when the substrates 5 and 6 are bonded together. Can be reliably crushed.

  Further, since the liquid crystal layer 7 is interposed between the substrates 5 and 6, the spacer 11 is not excessively crushed by the pressure P applied between the substrates 5 and 6 in the bubble removing process.

  Specifically, as a result of producing the 100-panel liquid crystal display panel 1, it was confirmed that there were 3 defective panels due to excessive liquid crystals, and 3 bubbles were generated in the low temperature test at −10 ° C., and 94-panel non-defective products were obtained.

Here, when the pressure of ² kg / cm ² was applied to the three panels in which bubbles B were generated at a low temperature of 10 ° C. or less, the spacer 11 could be shrunk and the volume of the liquid crystal display panel 1 decreased. In addition, the amount of liquid crystal material LC that had been deficient coincides with the amount dropped, so that it was possible to obtain a good panel free of bubbles even at −10 ° C.

  As a result, a total of 97 non-defective panels could be secured and the yield could be improved.

In the above-described embodiment, the pressure P applied between the substrates 5 and 6 in the bubble removal step is not limited to ² kg / cm ² , but can be any pressure that can effectively remove the bubbles B. Can be set arbitrarily.

  Further, the details of the liquid crystal display panel 1 are not limited to the above configuration.

It is explanatory sectional drawing which shows the liquid crystal display element of one embodiment of this invention. It is an explanatory top view which shows the sealing material application | coating process and liquid crystal dropping process of the manufacturing method of a liquid crystal display element same as the above. It is explanatory sectional drawing which shows the sealing material application | coating process and liquid crystal dropping process of the manufacturing method of a liquid crystal display element same as the above. It is explanatory sectional drawing which shows the bonding process of the manufacturing method of a liquid crystal display element same as the above. It is explanatory sectional drawing which shows the low temperature lighting test | inspection process and bubble removal process of the manufacturing method of a liquid crystal display element same as the above. It is explanatory sectional drawing which shows the liquid crystal display element obtained through the bubble removal process same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display panel as a liquid crystal display element 5 Array substrate as a substrate 6 Counter substrate as a substrate 7 Liquid crystal layer
11 Spacer B Bubble
LC liquid crystal material

Claims (2)

A liquid crystal display comprising a pair of substrates opposed to each other, a liquid crystal layer made of a liquid crystal material and interposed between the pair of substrates, and a spacer positioned between the substrates and maintaining a distance between the substrates A method for manufacturing an element, comprising:
A low temperature lighting inspection step of lighting the liquid crystal display element in a low temperature state of 10 ° C. or less;
A bubble removing step of shrinking the spacer by applying a predetermined pressure between the substrates in the low temperature state when bubbles are generated in the liquid crystal layer in the low temperature lighting inspection step. A method for producing a liquid crystal display element. The method for manufacturing a liquid crystal display element according to claim 1, wherein the pressure applied between the substrates in the bubble removing step is 2 kg / cm ² .

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