JP2008242193A - Liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce variations of contours in a gas barrier member between products and also improve workability, in a liquid crystal display element arranged with the gas barrier member at a substrate end for preventing gas from entering from an end surface of a flexible substrate, such as a plastic film. <P>SOLUTION: One polarizing plate 17b is extended from the other polarizing plate 17a and the end of the substrate 11a, 11b, A gas barrier member 18 is arranged so as to cover the end surface of the substrate 11a, 11b, by using an extending part of the polarizing plate 17a as a support. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display element comprising a flexible substrate such as a plastic film, wherein a gas barrier member is provided on the side surface of the substrate in order to prevent gas from entering the liquid crystal layer from the side surface of the substrate.

  A liquid crystal display element made of a plastic film substrate has been put into practical use as a display panel for a mobile phone by taking advantage of its light weight and thin properties. Recently, attention has been focused on the features of being hard to break, being bent, and having a high degree of freedom in planar shape, and various applied products have been proposed.

  Since these flexible materials are permeable to gas or water vapor unlike glass, gas or water vapor permeates under normal temperature and pressure. If a liquid crystal display element is made with a substrate using only a flexible material, the gas dissolves in the liquid crystal through the substrate, and if the gas dissolved in the liquid crystal reaches a saturated state, the liquid crystal display element is caused by an impact such as dropping. Bubbles may be generated inside. Therefore, a gas barrier layer made of an inorganic material or an organic material that hardly permeates gas has been provided on the surface of the substrate support material. The gas barrier layer may be provided on both sides of the substrate, but may be provided only on one side of the substrate in order to simplify the manufacturing process. When long-term reliability is important, gas barrier layers are often provided on both sides.

  A liquid crystal display element having a gas barrier layer suppresses the ingress of gas in a plan view. However, since the substrate support material is exposed on the side surface (hereinafter referred to as end surface) generated by cutting the substrate, gas enters the substrate from here. In order to ensure the flexibility of the substrate, the gas barrier layer on the liquid crystal layer side must use an organic substance having a high gas permeability, or use a very thin inorganic material film whose gas permeability has not been lowered. As a result, gas enters the liquid crystal layer from the end face of the substrate through the gas barrier layer in the long term (for example, Document 1).

  As a countermeasure against this, in Conventional Example 1 shown in Document 1 (Example 1 in the document), an epoxy adhesive was applied to the side surface of the liquid crystal display element including the seal to prevent gas from entering from the end face of the substrate. . This sectional view is shown in FIG. From the bottom of the figure, the liquid crystal display element includes a reflective plate 68, a polarizing plate 67, a substrate 61, a transparent electrode 62, an alignment film 63, a liquid crystal layer 66 mixed with a spacer 64, an alignment film 63, a transparent electrode 62, a substrate 61, and a polarization. Plates 67 are stacked. Here, the substrate 61 uses a polycarbonate film as a substrate support material, and has two gas barrier layers made of EVA (copolymer of ethylene and vinyl acetate) and phenoxy resin on both sides. In the side surface portion of the display element, an epoxy adhesive 69 is applied to the seal 65 and the end surfaces of the two substrates 61. In accordance with the description in Document 1, the substrate 61 is composed of a substrate support material and a gas barrier layer (the same applies hereinafter).

  In Conventional Example 2 shown in Document 1 (Example 4 in the document), the entire liquid crystal cell is infiltrated with an epoxy adhesive and then a polarizing plate is attached to prevent gas from entering from the end face of the substrate. This cross-sectional view is shown in FIG. The same members as those in Conventional Example 1 are denoted by the same numbers. The difference from Conventional Example 1 that can be seen from the figure is that there is a layer of epoxy adhesive 69 between the polarizing plate 67 and the substrate 61, and the polarizing plate 67 protrudes outside the substrate 61 (hereinafter referred to as extension). And the side epoxy adhesive is not raised to the left or right.

In addition, Document 1 shows an example in which a gas barrier member is provided on a side surface, an example in which an epoxy adhesive is applied to the side surface of a liquid crystal display element including a polarizing plate, an example in which an epoxy adhesive is applied only to an end surface of a substrate, ing.
JP 2001-221998 A

  In the method of applying the adhesive to the side surface as in Conventional Example 1 of Document 1, even if the adhesive force between the substrate and the adhesive or the surface tension of the adhesive is controlled, the adhesive droops. The cross-sectional shape is not clear. For this reason, the tolerance regarding the planar shape of the liquid crystal display element must be increased.

  Also, in the method of attaching the polarizing plate after infiltrating the entire liquid crystal cell into the epoxy adhesive as in Conventional Example 2 of Document 1, the outer tolerance can be reduced if attention is paid to the outer shape of the polarizing plate. However, since an adhesive substance exists on the surface of the substrate, there is a problem that the assembly work such as sticking a polarizing plate is hindered.

  Accordingly, an object of the present invention is to provide a liquid crystal display element in which a gas barrier member is provided at the end of the substrate in order to prevent gas from entering from the end surface of a flexible substrate such as a plastic film. Is to provide a liquid crystal display element that is small between products and has good workability.

  The present invention relates to a liquid crystal display element in which two flexible substrates are laminated through a seal and liquid crystal is injected into a space formed by the substrate and the seal, and is opposite to the surface on which the liquid crystal is injected. The upper and lower polarizing plates are provided on the side substrate surface, and one of the upper polarizing plate and the lower polarizing plate has a corner formed by extending from the other polarizing plate and the end of the substrate. A gas barrier member is provided so as to cover the end face of the substrate.

  Moreover, it is preferable that the gas barrier member is applied to the corners.

  Further, it is preferable that the side surface of the seal and the end surface of the substrate are substantially on the same plane.

  At the corner formed by the extended polarizing plate and the substrate end surface, a gas barrier member is provided so as to cover the substrate end surface by a method such as coating, using the surface of the extended polarizing plate as a support base. At this time, the gas barrier member does not protrude from the extending portion of the polarizing plate. The shape of the gas barrier member forms a curved surface that is convex upward or downward depending on the surface tension and quantity.

  According to the present invention, since the planar maximum outer shape is determined by the extending width of the polarizing plate, variation in the outer shape between products can be reduced only by paying attention to the outer shape of the polarizing plate. Furthermore, workability is good because a gas barrier member may be disposed on the end surface of the substrate with the surface of the extending portion of the polarizing plate as a support.

  The gap between the substrates or the thickness of the seal is about several μm to several tens of μm. For this reason, when the substrate end face is covered with the gas barrier member, the seal peripheral portion is naturally covered with the gas barrier member. When there is a slight distance between the edge of the substrate and the seal, and the gas barrier member and the side surface of the seal are to be completely in contact with each other, the gas barrier member is immersed in the space formed by the substrate and the seal. . At this time, it is necessary to adjust a certain waiting time and viscosity. If the side surface of the seal and the end surface of the substrate are substantially on the same plane, not only the time for the above-mentioned penetration is unnecessary, but also the viscosity management is moderated, so that workability is improved.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant description is omitted. The scale is changed as appropriate.
(First embodiment)

  FIG. 1 is a perspective view showing a liquid crystal display element according to the first embodiment of the present invention before a gas barrier member is provided. The corners will be described with reference to FIG. A lower substrate 11b, an upper substrate 11a, and an upper polarizer 17a are stacked on the polarizer 17b. In plan view, the substrates 11a and 11b and the polarizing plate 17a are equal in size, and the polarizing plate 17b is large. Therefore, the end surfaces of the substrates 11a and 11b and the polarizing plate 17a are aligned, and the polarizing plate 17b extends from these end surfaces. A region formed from this end face and the surface of the polarizing plate 17b is a corner.

  FIG. 2 is a cross-sectional view showing the liquid crystal display element according to the first embodiment of the present invention. In FIG. 2, the laminated structure of members will be described first. On the lower side of the figure, a polarizing plate 17b, a lower substrate support 11, a lower gas barrier layer 18, a lower transparent electrode 12, and a lower alignment film 13 are laminated. Similarly, on the upper side of the figure, the upper alignment film 13, the upper transparent electrode 12, the upper gas barrier layer 18, the upper substrate support 11 and the polarizing plate 17a are laminated. A laminate of the upper and lower substrate support members 11 and the gas barrier layer 18 is the upper and lower substrates 11a and 11b. Liquid crystal is injected into the space formed by the seal 15 between the upper and lower substrates 11a and 11b. A liquid crystal layer 16 is formed of the spacer 14 and the liquid crystal in this space.

  The upper and lower polarizing plates 17a and 17b have a thickness of 100 μm. The substrate support 11 is made of polycarbonate having a thickness of 100 μm, and the gas barrier layer 18 is made of silicon oxide SiOx having a thickness of 0.03 μm. The transparent electrode 12 is made of ITO having a thickness of 0.03 μm, and the alignment film 13 is made of polyimide having a thickness of 0.05 μm. The seal 15 has a width of 1 mm and is made of an epoxy resin, and the thickness of the liquid crystal layer 16 is 5 μm.

  Next, a structure related to the gas barrier member 19 will be described. The polarizing plate 17b extends 1.0 mm from the substrate 11b. A gas barrier member 19 made of an epoxy resin is applied to corners formed by the end face of the polarizing plate 17a, the end faces of the upper and lower substrates 11a and 11b, and the surface of the polarizing plate 17b. The gas barrier member 19 has a bottom that coincides with the extending portion of the polarizing plate 17b and covers the polarizing plate 17a and the end surfaces of the upper and lower substrates 11a and 11b. Further, the side surface of the seal 15 is in contact with the gas barrier member 19 along a straight line with the end surfaces of the substrates 11a and 11b. This indicates that the end surfaces of the substrates 11a and 11b and the side surface of the seal 15 are on the same plane. The hypotenuse of the gas barrier member draws a curve depending on the surface tension, but is shown as a straight line in the figure.

  FIG. 3 relates to the first embodiment of the present invention, and FIG. 3A is a plan view showing a liquid crystal display element drawn so that an electrode lead-out portion can be seen, a cross-sectional view thereof, and a cross-sectional view of a main part thereof It is. In FIG. 3, the connection state with the external circuit and the state of the gas barrier member similar to the actual one will be described.

  In FIG. 3A, the drive signal is transmitted to the liquid crystal display element via a flexible circuit board 32 (hereinafter referred to as FPC). A wiring electrode (not shown) on the lower surface of the FPC 32 is formed on the lower substrate 11b, and is a transparent electrode (not shown) exposed from a notched portion (hereinafter referred to as an electrode extraction portion) of the upper substrate 11a. And an anisotropic conductive sheet (not shown). In the electrode extraction part, the upper polarizing plate 17a is also cut out in the same shape, and the seal 15 also has a recess. The lower polarizing plate 17b extends outward from the lower substrate 11b. In addition, since the state before application | coating of a gas barrier member was drawn for description, the protection member of the gas barrier member 19 and FPC32 is not shown in figure.

FIG. 3B is a cross-sectional view taken along line AB in FIG. Gas barrier member 1
9 and after application of the protective member 31 of the FPC 32 are shown. From the bottom of the figure, the polarizing plate 17b, the lower substrate 11b, the liquid crystal layer 16, the substrate 11a, and the polarizing plate 17a are laminated, and the coating situation of the gas barrier member 19 at the left end is as described in FIG. . In the electrode extraction part on the right side of the figure, the gas barrier member 19 is applied to the space consisting of the polarizing plate 17a and the end surface of the substrate 11a, the seal 15 and the exposed surface of the substrate 11b, and the end portion of the FPC 32 (and part of the back surface). ing. After the FPC 32 was bonded, the gas barrier member was also applied to the electrode extraction portion when the gas barrier member 19 was applied to the peripheral portion. The protective member 31 of the FPC 32 is applied so as to penetrate into the space formed by the lower surface of the FPC 32, the end surface of the substrate 11b, and the extending portion (and end surface) of the polarizing plate 17. The protective member 31 also serves as a gas barrier for the substrate 11b in addition to preventing corrosion and disconnection of the FPC wiring.

  FIG. 3C is a cross-sectional view of a main part in which the left end of FIG. The thickness of the laminate of the polarizing plate 17a and the substrates 11a and 11b is approximately 0.6 mm, and the extending width of the polarizing plate 17b is 1.0 mm. The gas barrier member 19 has a curved line that protrudes downward.

FIG. 4 is a sectional view of an apparatus using the liquid crystal display element according to the first embodiment of the present invention. A polarizing plate 17a, a substrate 11a, a substrate 11b, and a polarizing plate 17b are stacked from the bottom of the chassis toward the viewer. The seal, the liquid crystal layer, etc. are not shown. By reversing the front and back in this way, the gas barrier material 19 is shielded by the polarizing plate 17b and is hardly visible. Since the gas barrier member 19 is completely shielded by the polarizing plate 17b when trying to make the device thinner by matching the surface of the liquid crystal element and the upper surface of the chassis, just pay attention to the accuracy of the outer shape of the polarizing plate 17b. In this way, the design can be improved.
(Second Embodiment)

FIG. 5 is a cross-sectional view showing a liquid crystal display device according to another embodiment of the present invention. A second embodiment will be described with reference to FIG. From the bottom of the figure, a polarizing plate 54a, a laminate 52 (hereinafter referred to as a plastic cell) in which two plastic substrates are stacked with a liquid crystal layer interposed therebetween, and a polarizing plate 51a are stacked. The polarizing plate 54 a is wider than the plastic cell 52, while the polarizing plate 51 a is narrower than the plastic cell 52. A gas barrier member 53a is applied so as to cover the end surface of the polarizing plate 51a and the end surface (and a part of the surface) of the plastic cell 52 with the extended portion of the polarizing plate 54a as a support. In order to secure a sufficient thickness (lateral direction) of the gas barrier member 53a even at the corner on the upper side (polarizing plate 51a side) of the plastic cell 52, the cross section of the gas barrier member 53a has a convex curve.
(Third embodiment)

A third embodiment will be described with reference to FIG. From the bottom of the figure, a polarizing plate 54b, a plastic cell 52, and a polarizing plate 51b are stacked. The polarizing plate 51b is slightly wider than the plastic cell 52, and the polarizing plate 54b is wider than the polarizing plate 51b. A gas barrier member 53b is applied so as to cover the end surface (and bottom surface) of the polarizing plate 51b and the end surface of the plastic cell 52 with the extending portion of the polarizing plate 54b as a support. By extending the polarizing plate 51b, a sufficient thickness (lateral direction) of the gas barrier member can be secured even at the upper corner (the polarizing plate 51b side) of the plastic cell 52.
(Fourth embodiment)

A fourth embodiment will be described with reference to FIG. From the bottom of the figure, a polarizing plate 54c, a plastic cell 52, and a polarizing plate 51c are stacked. The polarizing plate 51c extends from the plastic cell 52 on the right side of the drawing, and the polarizing plate 54c extends from the plastic cell 52 on the left side of the drawing. On the right side of the figure, the gas barrier member 53c is applied so as to cover the end face of the plastic cell 52 and the end face of the polarizing plate 54c, with the extending portion of the polarizing plate 51c as a support. On the left side of the figure, the gas barrier member 53c is applied so as to cover the end face of the plastic cell 52 and the end face of the polarizing plate 51c, with the extending portion of the polarizing plate 54c as a support. By changing the polarizing plate to be extended depending on the side of the liquid crystal display element, it is possible to increase the degree of freedom when incorporating it into the chassis.

1 is a perspective view showing a liquid crystal display device according to a first embodiment of the present invention. It is sectional drawing which shows the liquid crystal display element which concerns on the 1st Embodiment of this invention. 1A is a plan view showing a liquid crystal display device according to a first embodiment of the present invention, FIG. It is sectional drawing of the apparatus using the liquid crystal display element which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the liquid crystal display element which concerns on other embodiment of this invention. It is sectional drawing of the prior art example 1. FIG. It is sectional drawing of the prior art example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Substrate support material, 11a, 11b, 61 ... Substrate, 12, 62 ... Transparent electrode, 13, 63 ... Alignment film, 14, 64 ... Spacer, 15, 65 ... Seal, 16, 66 ... Liquid crystal layer, 17a, 17b , 51a, 51b, 51c, 54a, 54b, 54c, 67 ... polarizing plate, 18 ... gas barrier layer, 19, 53a, 69 ... gas barrier member, 52 ... plastic cell, 68 ... reflector.

Claims (3)

  In a liquid crystal display element in which two flexible substrates are stacked through a seal and liquid crystal is injected into a space formed from the substrate and the seal, the substrate surface opposite to the surface into which the liquid crystal is injected Each polarizing plate includes a polarizing plate, and one polarizing plate extends from the other polarizing plate and an end portion of the substrate, and covers the end surface at a corner formed by the extending portion of the polarizing plate and the end surface of the substrate. A liquid crystal display element comprising a gas barrier member provided on the liquid crystal display element.   The liquid crystal display element according to claim 1, wherein the gas barrier member is applied to the corner portion. 3. The liquid crystal display element according to claim 1, wherein a side surface of the seal and an end surface of the substrate are substantially on the same plane.

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