JP2012208467A - Liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display element capable of confining a liquid crystal amount to an appropriate area and preventing occurrence of air bubbles and display spots.SOLUTION: A liquid crystal display element 10 comprises: a pair of substrates 11 and 12 at least one of which has flexibility; and a liquid crystal layer 13 that is encapsulated between the pair of substrates 11 and 12. An area where either one of the pair of substrates 11 and 12 contacts the liquid crystal layer 13 is divided into a display area 6 and a non-display area 5. The display area 6 includes multiple spacers 15 that are arranged between the pair of substrates 11 and 12, and hold spaces between the pair of substrates 11 and 12. The non-display area 5 is provided with an area including no spacers, and has a smaller average cell gap than the display area 6.

Description

  The present invention relates to a liquid crystal display element having flexibility.

  In recent years, so-called flat panel displays have been widely applied as display elements in various fields. The liquid crystal display element as an example is widely used in the mobile display field such as a mobile phone and a PDA by making use of the features of thinness, light weight, and low power consumption, and a pair of glass substrates face each other with a predetermined interval. In general, an annular sealing material is used and a liquid crystal layer is sandwiched between glass substrates (Patent Document 1). However, the display is further reduced in thickness and weight, and leads to a wearable display. Development of a flexible substrate using plastic or the like instead of glass is in progress.

  In such a liquid crystal display element having a liquid crystal layer sealed between a pair of substrates, a spacer is disposed between the pair of substrates to hold the liquid crystal layer. For example, Patent Document 2 (WO 2009/054292) In order to eliminate the cause of bubble generation by distributing the distribution of the spacer arrangement density and collect bubbles in the area where there is little problem, the spacer arrangement density in the peripheral area is set to the spacer in the display area. The arrangement density is lower.

  In paragraphs 0027 to 0029, 0052 and FIGS. 1 and 2 of Patent Document 3 (WO 2006/077838), and FIGS. 1 and 2, the bottom area of the columnar spacer in the non-display area is made smaller than that in the display area. The non-display area is more easily dented than the area, and even when the temperature is lowered or the substrate is deformed, the liquid crystal corresponding to the recessed volume of the non-display area moves to the display area, thereby suppressing the deterioration of reliability due to bubbles.

  In paragraphs 0030 to 0034 of Patent Document 4 (Japanese Patent Publication No. 2004-126197) and FIG. 1, the volume distribution of the liquid crystal member is reduced by making the spacer distribution density smaller in the peripheral portion than in the central portion. However, since the part where the spacer is sparse is deformed, bubbles are prevented from being generated in the liquid crystal member.

JP 2010-217234 A WO 2009/054292 publication WO 2006/077838 Japanese Patent No. 2004-126197

  As described above, in a liquid crystal display element having a liquid crystal layer sealed between a pair of substrates, the cell gap is changed by the density of the spacer to eliminate the cause of bubble generation. In addition, the amount of deflection of the substrate is changed by the size of the bottom area of the columnar spacer, and even when the temperature drops or the substrate is deformed, the deterioration of reliability due to bubbles is suppressed, and the amount of deflection is changed by the density of the spacer density. However, if a flexible substrate such as plastic is used instead of glass, for example, if the amount of liquid crystal is less than the appropriate area determined by the design panel volume, Air bubbles may be generated by the presence of the spacer. For this reason, when an amount of liquid crystal larger than the design panel volume is encapsulated, the substrate itself is flexible, so that the substrate is deformed by attempting to include an excessive amount of liquid crystal, thereby generating display spots. There was a problem.

  The problem to be solved by the present invention has been made in view of such circumstances, and by providing a liquid crystal display element capable of controlling the amount of liquid crystal to an appropriate region and preventing the occurrence of bubbles and display spots. is there.

  In order to solve the above-described problems and achieve the object, the present invention is configured as follows.

  The invention according to claim 1 includes a pair of substrates, at least one of which has flexibility, and a liquid crystal layer sealed between the pair of substrates, and one of the pair of substrates and the liquid crystal layer are The contact area is divided into a display area and a non-display area, and the display area includes a plurality of spacers arranged between the pair of substrates and holding a gap between the pair of substrates. In the liquid crystal display element, a region without a spacer is provided in the region, and an average cell gap of the non-display region is smaller than an average cell gap of the display region.

  According to a second aspect of the present invention, in the non-display area, a spacer is provided on the seal area side, and an area without a spacer is provided on the display area side. It is a display element.

According to a third aspect of the present invention, in the region not provided with the spacer in the non-display region, the interval between the pair of substrates in the seal region is wider than the interval between the pair of substrates in the display region. The liquid crystal display element according to claim 1.

According to a fourth aspect of the present invention, in the non-display area, a spacer is disposed on the seal area side, an area not provided with a spacer is provided on the display area side, and an area not provided with the spacer in the non-display area is 2. The liquid crystal display element according to claim 1, wherein a distance between the pair of substrates in the seal region is wider than a distance between the pair of substrates in the display region.

  The invention according to claim 5 is characterized in that the amount of bending of the substrate in the non-display area is larger than the amount of bending of the substrate in the display area. It is a liquid crystal display element of description.

  According to a sixth aspect of the present invention, in the non-display area, the average cell gap changes according to the amount of liquid crystal sealed, and does not exceed the average cell gap of the display area. It is a liquid crystal display element of any one of thru | or 5.

  With the above configuration, the present invention has the following effects.

  According to the first to sixth aspects of the present invention, the region where one of the pair of substrates is in contact with the liquid crystal layer is divided into a display region and a non-display region, and the display region is disposed between the pair of substrates. And a plurality of spacers for holding a gap between the pair of substrates, and a non-display region is provided with a region without a spacer, and the average cell gap of the non-display region is smaller than the average cell gap of the display region. As a result, the cell gap is stabilized regardless of the amount of liquid crystal and the generation of bubbles can be suppressed, and the performance of the product is improved by expanding the margin with respect to the amount of liquid crystal and improving the cell gap variation.

  Further, in a liquid crystal dropping injection process (ODF: One Drop Fill), a region where one of the pair of substrates and the liquid crystal layer is in contact is divided into a display region and a non-display region, and the non-display region does not include a spacer. Therefore, the movement of the liquid crystal is restricted because the substrate bends between the pair of substrates and the spacing between the substrates is narrowed, and the pre-curing seal and the liquid crystal are not easily in contact with each other. Product quality and reliability are improved. Further, by providing an area without a spacer in the non-display area, the amount of bending of the substrate in the non-display area is larger than the amount of bending of the substrate in the display area, and the non-display area depends on the amount of liquid crystal to be sealed. Since the average cell gap changes and does not exceed the average cell gap of the display area, the amount of liquid crystal can be controlled to an appropriate area, and bubbles and display spots can be prevented from being generated.

It is a top view of the liquid crystal display element of 1st Embodiment. It is sectional drawing of a non-display area | region and a display area part. It is a figure explaining that an average cell gap changes with the change of the amount of liquid crystals. It is a figure explaining the liquid crystal amount dependence of a cell gap. It is a figure explaining the liquid crystal amount dependence of the variation of a cell gap. It is a top view of the liquid crystal display element of 2nd Embodiment. It is sectional drawing of another non-display area | region and a display area part. It is sectional drawing of another non-display area | region and a display area part. It is a figure explaining the liquid crystal amount dependence of the cell gap when using the plastic substrate from which an elasticity modulus differs. It is a figure explaining the liquid crystal amount dependence of the variation in a cell gap when using the plastic substrate from which an elasticity modulus differs. It is a figure explaining the liquid crystal amount dependence of the cell gap when the magnitude | size of the area | region which is not provided with the spacer of a non-display area | region is changed. It is a figure explaining the liquid crystal amount dependence of the variation of a cell gap when the magnitude | size of the area | region which is not provided with the spacer of a non-display area | region is changed. It is a figure explaining the liquid crystal amount dependence of the cell gap when the magnitude | size of the area | region which does not provide the spacer of a non-display area | region in the plastic substrate from which an elasticity modulus differs is changed. It is a figure explaining the liquid crystal amount dependence of the variation of a cell gap when the magnitude | size of the area | region which is not provided with the spacer of a non-display area | region in the plastic substrate from which an elasticity modulus differs is changed. It is a figure of the table | surface which shows generation | occurrence | production of a bubble and a display spot in a comparative example with respect to an Example.

  Hereinafter, embodiments of the liquid crystal display element of the present invention will be described. The embodiment of the present invention shows the most preferable mode of the present invention, and the present invention is not limited to this.

[First Embodiment of Liquid Crystal Display Element]
FIG. 1 is a plan view of a liquid crystal display element, FIG. 2 is a cross-sectional view of a non-display area and a display area portion, and FIG.

  The liquid crystal display element 10 of this embodiment includes a flexible first substrate 11, a flexible second substrate 12 that is disposed opposite to the first substrate 11, and a first substrate 11. And a liquid crystal layer 13 sealed inside a sealing region provided between the second substrate 12 and the second substrate 12 so that the whole can be bent and deformed. The sealing region is formed by a sealing material 14 having a substantially rectangular frame shape.

  The first substrate 11 is, for example, a rectangular plastic substrate that is a transparent flexible substrate such as polycarbonate, a moisture-proof film laminated on the surface of the plastic substrate on the liquid crystal layer side, and laminated on the surface of the moisture-proof film. A plurality of pixel electrodes, a plurality of thin film transistors (hereinafter abbreviated as TFTs) connected to the pixel electrodes, and an alignment film that covers the pixel electrodes, the TFTs, and the like are formed.

  The second substrate 12 is a plastic substrate similar to the first substrate 11, a moisture-proof film laminated on the surface of the plastic substrate on the liquid crystal layer side, and a transparent layer formed on the moisture-proof film and made of ITO or the like. An electrode and an alignment film that covers the transparent electrode are formed. Further, a color filter is formed on the second substrate 12.

  The liquid crystal layer 13 is enclosed between the first substrate 11 and the second substrate 12 in a state surrounded by the sealing material 14 having a substantially rectangular frame shape on the second substrate 12. A non-display area 5 that does not contribute to display is formed inside the sealing material 14, and a display area 6 that contributes to display is formed inside the non-display area 5.

  For the sealing material 14, it is possible to apply a non-conductive resin having strong adhesive properties such as an epoxy resin. Moreover, it is more preferable to apply a thermoplastic resin having high elasticity such as a silicone resin or a thermoplastic elastomer to the sealing material 14. The sealing material 14 is formed along the four sides of the first substrate 11 and the second substrate 12, and holds the first substrate 11 and the second substrate 12 in close contact with each other. As the liquid crystal material of the liquid crystal layer 13, for example, nematic liquid crystal is used, but cholesteric liquid crystal, smectic liquid crystal, or the like may be used.

  As described above, the area where the first substrate 11, the second substrate 12, and the liquid crystal layer 13 are in contact is divided into the display area 6 and the non-display area 5 surrounding the display area 6. Is provided between the first substrate 11 and the second substrate 12, and is provided with a plurality of spacers 15 for maintaining a gap between the substrates, and the non-display region 5 is provided with a region not provided with a spacer. For this reason, the first substrate 11 and the second substrate 12 may come into contact with each other, so that the electrodes and the like are not exposed on the surface where the liquid crystal layer 13 of the first substrate 11 and the second substrate 12 is in contact. It is self-evident that the two substrates are prevented from being electrically short-circuited unnecessarily by using means such as covering the film or partially arranging spacers.

  The spacer 15 is configured by a photo spacer formed in a columnar shape such as a substantially cylindrical shape, for example, and is arranged over the entire display area 6. For example, a particulate spacer such as a resin can be used as the spacer 15.

  The display area 6 is formed in a rectangular shape, and the spacer 15 is formed, whereby the thickness of the liquid crystal layer 13 that is the distance between the first substrate 11 and the second substrate 12 is maintained constant, and the non-display area By providing a region without a spacer in 5, the average cell gap of the non-display region 5 is smaller than the average cell gap of the display region 6.

  As described above, the liquid crystal display element 10 has a region in which the first substrate 11, the second substrate 12, and the liquid crystal layer 13 are in contact with each other between the first substrate 11 and the second substrate 12. The display cell 6 is divided into a region 6 and a non-display region 5 surrounding the display region 6, and the average cell gap (the thickness of the liquid crystal layer 13) of the non-display region 5 is the average cell gap (the thickness of the liquid crystal layer 13) of the display region 6. It is smaller than that.

  That is, when the liquid crystal display element 10 is provided with the non-display area 5 without the spacer and the display area 6 with the spacer, the liquid crystal amount of the liquid crystal layer 13 is equal to the design volume (panel area × spacer height) as shown in FIG. If less, the first substrate 11 and the second substrate 12 receive the pressure corresponding to the differential pressure of “design volume−liquid crystal amount” by the atmospheric pressure at the first substrate 11 and the second substrate 12. However, in the non-display area 5, the amount of bending of the substrate is larger than the amount of bending of the substrate in the display area 6. As a result, the average cell gap is smaller than that of the display area 6 having spacers.

  As shown in FIG. 3, the average cell gap of the non-display area 5 and the display area 6 changes and does not exceed the average cell gap of the display area 6 according to the amount of liquid crystal sealed. The average cell gap of the non-display area 5 is smaller than the average cell gap of the display area 6, the first substrate 11 and the second substrate 12 are greatly bent, and the change of the average cell gap is large. On the other hand, since the average cell gap of the display area 6 is provided with the spacer, the average cell gap of the non-display area 5 is larger, the first substrate 11 and the second substrate 12 are less bent, and the change of the average cell gap is large. Is small.

  The cell gap change and cell gap variation change when the amount of liquid crystal was changed were tested. In this test, a composite material of glass fiber and curable resin is used as the substrate, the thickness of the substrate is 100 μm, and the elastic modulus is 25 GPa. The height of the spacer used is 5 μm.

  The cell gap change test is based on the liquid crystal filling rate dependence of the cell gap on two types of 3.5-inch liquid crystal panels: a normal panel without a non-display area and a panel according to the present invention with a non-display area. Asked. Specifically, the cell gap average value of the display area of each panel produced by changing the amount of liquid crystal was measured, and the degree of change with respect to the liquid crystal filling rate was examined. Since the target panel uses a flexible substrate as described above, the cell gap of the entire display region was measured, and the average value was obtained. The measurement was carried out by moving the probe light with a He—Ne laser focused to 500 μmφ by 1 mm in length and width. The number of measured data is approximately 4000 points.

  In the cell gap variation change test, the average value of the cell gap (FIG. 4) and the standard deviation (σ) (FIG. 5) that causes the variation of the cell gap were obtained from 4000 cell gap data obtained by measurement.

  The test result of the cell gap change will be described with reference to FIG. FIG. 4 is a diagram for explaining the dependency of the cell gap on the amount of liquid crystal. The horizontal axis shows the liquid crystal filling rate (%), the vertical axis shows the average cell gap (μm), the non-display area 5 has no buffer and there is a buffer area, and the spacer is arranged in the non-display area 5 The case where there is no buffer region is indicated by x.

  According to this test result, the cell gap change when the amount of liquid crystal is changed is in the range of about 5.1 (μm) to 5.2 (μm) when there is no spacer in the non-display area 5 and there is a buffer area. In the case where the spacer is arranged in the non-display area 5 and there is no buffer area, the change is in the range of about 4.9 (μm) to 5.3 (μm), and the change is large. In the case where the spacer is arranged in the non-display area 5 and there is no buffer area, when the liquid crystal filling rate (%) is in the range of about 85% to about 95%, the amount of liquid crystal is insufficient and bubbles are generated. As described above, by providing the buffer region without disposing the spacer in the non-display region 5, the change in the cell gap with respect to the amount of liquid crystal is gradual, the stability of the cell gap is improved, and bubbles are hardly generated. In this test result, bubbles were not generated.

  The cell gap is defined by the spacer to be used, but in the case where the buffer region in this test was provided, the result was that the cell gap was more stable than the spacer height. This is because when the liquid crystal moves to a buffer area without a spacer, the liquid crystal must invade against the pressure between the substrates pressed by the atmosphere, and the force pushed out of the display area and the buffer area are greatly suppressed. It is considered that the cell gap is defined by the balance with the atmospheric pressure. As described above, the buffer region in which the spacer is not arranged is considered to maintain a constant cell gap in the display region because it functions as a barrier when the liquid crystal moves from the display region to the buffer region.

  The test result of the cell gap variation change will be described with reference to FIG. FIG. 5 is a diagram for explaining the dependency of the cell gap variation on the amount of liquid crystal. The horizontal axis indicates the liquid crystal filling rate (%), the vertical axis indicates the cell gap variation (3σ) (μm), the non-display area 5 has no buffer and has a buffer area, and the non-display area 5 The case where a spacer is arranged and there is no buffer region is indicated by x.

  According to this test result, the cell gap variation change when the amount of liquid crystal is changed is about 0.15 (μm) when the non-display region 5 has no spacer and there is a buffer region, but the change is small. In the case where a spacer is arranged in the region 5 and there is no buffer region, the change is in the range of about 0.15 (μm) to 0.3 (μm), and the change is large. Thus, by providing the buffer region without arranging the spacer in the non-display region 5, the cell gap variation with respect to the amount of liquid crystal is constant, the uniformity of the cell gap is improved, the stability of the cell gap is improved, Air bubbles are less likely to occur, improving product performance. In addition, in the liquid crystal dropping step, since no spacer is provided in the non-display area, the movement of the liquid crystal is regulated because the substrate is bent between the pair of substrates, and the spacing between the substrates is narrowed. The pre-curing seal does not impair the performance of the liquid crystal, improving the product quality and reliability.

  Further, the average cell gap of the non-display area 5 and the display area 6 changes according to the amount of liquid crystal to be sealed. At this time, the thickness of the liquid crystal layer (cell gap) is determined by the degree of bending of the substrate. The cell gap shows a value corresponding to the amount of deflection between the spacers, but the average value of the cell gap in a region wider than the spacer interval is defined as an average cell gap (or each of the display region 6 and the non-display region 5). Average cell gap), the average cell gap can be treated as an index having a correlation with the amount of bending of the substrate.

  Therefore, the area in contact with the liquid crystal layer 13 is divided into a display area 6 and a non-display area 5 surrounding the display area 6, and the average cell gap of the non-display area 5 is smaller than the average cell gap of the display area 6. Thus, the non-display area 5 can control the amount of liquid crystal to an appropriate area by changing the average cell gap according to the amount of liquid crystal sealed and not exceeding the average cell gap of the display area. It is possible to prevent the occurrence of display spots.

[Second Embodiment of Liquid Crystal Display Element]
A second embodiment will be described with reference to FIG. FIG. 6 is a plan view of the liquid crystal display element. In this embodiment, the non-display area 5 that does not contribute to display is formed only inside one side of the sealing material 14, and the display area 6 that contributes to display is formed inside the other three sides.

  Similarly to the first embodiment, this embodiment is divided into a display area 6 and a non-display area 5, and the display area 6 includes a plurality of spacers that hold a gap between a pair of substrates. The non-display area 5 is provided with an area without a spacer, and the average cell gap of the non-display area 5 is configured to be smaller than the average cell gap of the display area 6.

(Configuration of hidden area)
In the first and second embodiments, the non-display area is provided with an area not provided with a spacer as shown in FIGS. 2 and 3, but it is configured as shown in FIGS. can do.

  In the embodiment of FIG. 7, in the non-display area 5, a spacer 50 is provided on the seal area side, and an area without a spacer is provided on the display area side. In this embodiment, by disposing the spacer 50 on the seal region side, the liquid crystal 13 can be positively accumulated in the non-display region 5 by the spacer 50.

  In the embodiment of FIG. 8, in the region not provided with the spacer in the non-display region 5, the length L1 of the sealing material 14 is longer than the length L2 of the spacer 50, and the first substrate 11 and the first substrate 11 in the display region 6 The interval between the first substrate 11 and the second substrate 12 in the sealing region is made wider than the interval between the two substrates 12, and the liquid crystal 13 is positively accumulated in the non-display region 5 by this widened portion. be able to.

  As described above, the non-display area 5 is provided with an area not provided with a spacer, so that the amount of bending of the substrate in the non-display area 5 is larger than the amount of bending of the substrate in the display area 6. By changing the average cell gap according to the amount of liquid crystal to be sealed and not exceeding the average cell gap of the display region 6, the amount of liquid crystal can be controlled to an appropriate region, and bubbles and display spots can be prevented from being generated. Is possible.

(substrate)
As the transparent flexible substrate, a composite material of glass fiber and curable resin was used, but there is no particular limitation, and any conventionally known substrate can be used. Examples of the resin forming the plastic substrate include thermoplastic resins such as polycarbonate, polyarylate, polyethersulfone, polyester, polysulfone, polymethyl methacrylate, polyetherimide, and polyamide, epoxy resin, unsaturated polyester, and polydiallyl. Examples thereof include thermosetting resins such as phthalate and polyisobornyl methacrylate. 1 type, or 2 or more types can be used for this resin, and it can also be used as a copolymer and a mixture with another component. The thickness and elastic modulus of such a transparent flexible substrate may be determined according to the specifications of the liquid crystal display element so that the flexible substrate can follow and bend according to the amount of liquid crystal to be sealed.

  4 and 5 show the test results on a plastic substrate having an elastic modulus of 25 GPa, but the same test was performed on a plastic substrate having an elastic modulus of 2 GPa. The thickness of the substrate at this time is 100 μm.

  In the cell gap variation change test, the average value of the cell gap (FIG. 9) and the standard deviation (σ) (FIG. 10) that causes the variation of the cell gap are obtained from 4000 cell gap data obtained in the same manner. It was.

  The test result of the cell gap change will be described with reference to FIG. FIG. 9 is a diagram for explaining the dependency of the cell gap on the amount of liquid crystal. The horizontal axis shows the liquid crystal filling rate (%), the vertical axis shows the average cell gap (μm), the non-display area 5 has no buffer and there is a buffer area, and the spacer is arranged in the non-display area 5 The case where there is no buffer region is indicated by x.

  According to this test result, the cell gap change when the amount of liquid crystal is changed is in the range of about 5.05 (μm) to 5.2 (μm) when there is no spacer in the non-display area 5 and there is a buffer area. In particular, in the range where the liquid crystal filling rate exceeds 90%, the cell gap is almost constant.

  In the case where a spacer is arranged in the non-display area 5 and there is no buffer area, it changed in the range of about 4.9 (μm) to 5.1 (μm), and the change was large. Further, when a spacer is arranged in the non-display area 5 and there is no buffer area, when the liquid crystal filling rate (%) is 96 (%), the amount of liquid crystal is insufficient and bubbles are generated. As described above, by providing the buffer region without disposing the spacer in the non-display region 5, the change in the cell gap with respect to the amount of liquid crystal is gradual, the stability of the cell gap is improved, and bubbles are hardly generated. In this test result, bubbles were not generated.

  The test result of the cell gap variation change will be described with reference to FIG. FIG. 10 is a diagram for explaining the dependency of cell gap variation on the amount of liquid crystal. The horizontal axis indicates the liquid crystal filling rate (%), the vertical axis indicates the cell gap variation (3σ) (μm), the non-display area 5 has no buffer and has a buffer area, and the non-display area 5 The case where a spacer is arranged and there is no buffer region is indicated by x.

  According to this test result, the cell gap variation change when the amount of liquid crystal is changed is 0.20 (μm) or less in the test range when there is no spacer in the non-display area 5 and there is a buffer area. Before and after the filling rate of 100 (%), it is as small as about 0.15 (μm). However, when a spacer is arranged in the non-display region 5 and there is no buffer region, the change with respect to the liquid crystal filling rate is not stable and the liquid crystal filling rate is 100. Above (%), it exceeds 0.2 (μm).

  Thus, by providing the buffer region without arranging the spacer in the non-display region 5, the cell gap variation with respect to the amount of liquid crystal is constant, the uniformity of the cell gap is improved, the stability of the cell gap is improved, Air bubbles are less likely to occur, improving product performance. In addition, in the liquid crystal dropping step, since no spacer is provided in the non-display area, the movement of the liquid crystal is regulated because the substrate is bent between the pair of substrates, and the spacing between the substrates is narrowed. The pre-curing seal does not impair the performance of the liquid crystal, improving the product quality and reliability.

(Spacer)
The spacer is formed by exposing and developing after applying a photosensitive resin film, but is not limited thereto. The spacer shape, spacer height, and spacer arrangement density may be determined according to the substrate spacing design of the liquid crystal display element. In the case where the liquid crystal material is supplied by a vacuum injection method, a spacer may be formed in a region serving as an injection path.

  In the present invention, the average cell gap of the non-display area 5 is configured to be smaller than the average cell gap of the display area 6, and the amount of bending of the substrate in the non-display area 5 is larger than the amount of bending of the substrate in the display area 6. In addition, the non-display area 5 is characterized in that the average cell gap changes according to the amount of liquid crystal to be sealed and does not exceed the average cell gap of the display area 6.

(Size of buffer area)
The buffer region in the present invention is characterized by having a function of storing excess liquid crystal. In order to confirm the degree of the effect, the size of the buffer region was changed, and the cell gap change and the cell gap variation change when the liquid crystal amount was changed were tested. There are two types of substrates used in this test, elastic modulus 25 GPa and 2 GPa. The height of the spacer used is 5 μm.

  The cell gap change test is based on the liquid crystal filling rate dependence of the cell gap on two types of 3.5-inch liquid crystal panels: a normal panel without a non-display area and a panel according to the present invention with a non-display area. Asked. Specifically, the cell gap average value of the display area of each panel produced by changing the amount of liquid crystal was measured, and the degree of change with respect to the liquid crystal filling rate was examined. Since the target panel uses a flexible substrate as described above, the cell gap of the entire display region was measured, and the average value was obtained. The measurement was carried out by moving the probe light with a He—Ne laser focused to 500 μmφ by 1 mm in length and width. The number of measured data is approximately 4000 points.

  In the cell gap variation test, the average value of the cell gap and the standard deviation (σ) that causes the variation of the cell gap were obtained from 4000 cell gap data obtained by measurement.

  The test results for the substrate elastic modulus of 25 GPa are shown in FIG. 11 (average cell gap value) and FIG. 12 (standard deviation for variation in cell gap), and the test results for the substrate elastic modulus 2 GPa are shown in FIG. 13 (average cell gap value). ) And FIG. 14 (standard deviation that causes variations in the cell gap). The size of the buffer area at this time is shown in the drawing as a ratio to the display area, and 0 (%) represents a conventional panel having a buffer area size of 0%, that is, no buffer area.

  In both of the substrate elastic modulus 25 GPa and 2 GPa, it was found that the larger the buffer region, the more stable the average cell gap and its variation (3σ) with respect to the liquid crystal filling rate, and a greater effect can be obtained. By providing a buffer region of about 5%, the change amount of the average cell gap with respect to the amount of liquid crystal becomes small, and the effect can be obtained. No bubble generation was seen in all panels provided with a buffer area.

  In the configuration of the present invention, the amount of bending of the substrate in the non-display area 5 is made larger than the amount of bending of the substrate in the display area 6 by not forming a spacer in the non-display area 5. By setting the elastic coefficient, the size of the spacer at that time, the size of the non-display area 5, the size of the elastic coefficient of the substrate and the spacer, and the like in an appropriate range, the amount of bending of the substrate in the non-display area 5 6 to be larger than the bending amount of the substrate.

[Example 1]
Next, examples of the liquid crystal display element will be described. As the substrates 11 and 12, a composite material of glass fiber and curable resin is used, the thickness is 100 μm, and the elastic modulus is 25 GPa. An SiO film is formed on the surface of at least one of the substrates 11 and 12 to a thickness of about 1000 mm by sputtering, and this is used as a moisture-proof film. Subsequently, for each of the substrates 11 and 12, ITO was sputtered on the surface of the moisture-proof film to form electrodes. Further, a TFT or the like was formed on the substrate 11 and a color filter or the like was formed on the substrate 12 by a known method.

  Next, a negative photosensitive resin (for example, JNPC80 manufactured by JSR Corporation) was applied to the substrate 11, and a plurality of photo spacers were formed at predetermined intervals by photolithography. The photo spacer was formed in a substantially cylindrical shape having a height of 5 μm and a diameter of 20 μm.

  In the non-display area 5, the photo spacers were not arranged, and the arrangement density of the spacers in the display area 6 was 100 (pieces / square mm).

  Thereafter, an alignment film was applied to the substrate 12 by spin coating so as to cover the transparent electrode and then baked to form an alignment treatment by rubbing.

  Subsequently, a liquid crystal material is injected between the substrate 11 and the substrate 12 by a dropping injection method. That is, first, the sealing material 14 before curing is supplied to the non-display area 5 of the substrate 12 by a dispenser or the like.

  Next, a liquid crystal material is supplied to a region inside the sealing material 14 in the substrate 12 and inside the sealing partition wall, and the substrate 11 and the substrate 12 are bonded to each other in a vacuum, heated and pressurized. The sealing material 14 was cured. The liquid crystal material was supplied in the range of 90 to 100% of the liquid crystal filling rate, and the presence / absence of bubbles and display spots were evaluated.

  The amount of deflection of the substrate in the non-display area 5 changes more greatly than the amount of deflection of the substrate in the display area 6 according to the amount of liquid crystal to be enclosed, and does not exceed the average cell gap of the display area 6. It was possible to control to an appropriate area.

  Therefore, when a flexible substrate such as plastic is used instead of glass, for example, even if a larger amount of liquid crystal than the design panel volume is encapsulated, the substrate in the non-display area 5 according to the amount of encapsulated liquid crystal. The amount of deflection of the liquid crystal changes more greatly than the amount of deflection of the substrate in the display region 6 and the amount of liquid crystal can be controlled to an appropriate region, so that it is possible to prevent the generation of bubbles and display spots. The results are shown in the table of FIG.

[Example 2]
Although it is the same as that of Example 1, the board | substrates 11 and 12 formed with the polycarbonate were used. This substrate has a thickness of 50 μm and an elastic modulus of 2 GPa. The photo spacer is formed in a substantially cylindrical shape having a height of 5 μm and a diameter of 20 μm. The photo spacer has a spacer arrangement density of 400 in the display area 6 without arranging the spacer in the non-display area 5. It was dense (pieces / square mm).

  In Example 2, since the films of the substrates 11 and 12 are thinner and softer than in Example 1, the arrangement density of the spacers in the display area is set to about 50 μm pitch in terms of pitch, and the density is more flexible than in Example 1. Is preferably increased.

  The amount of deflection of the substrate in the non-display area 5 changes more greatly than the amount of deflection of the substrate in the display area 6 according to the amount of liquid crystal to be enclosed, and does not exceed the average cell gap of the display area 6. It was possible to control to an appropriate region, and it was possible to prevent the generation of bubbles and display spots. The results are shown in the table of FIG.

[Comparative Example 1]
As in the first embodiment, the photo spacers have a spacer arrangement density of 100 (pieces / square mm) in the non-display area 5 and a spacer arrangement density of 100 (pieces / square mm) in the display area 6. It was.

  The amount of bending of the substrate in the non-display area 5 changes in the same way as the amount of bending of the substrate in the display area 6 according to the amount of liquid crystal to be sealed, and the amount of liquid crystal cannot be controlled to an appropriate area, thereby preventing the generation of bubbles. I could not. The results are shown in the table of FIG.

[Comparative Example 2]
As in Comparative Example 1, the photo spacers have a spacer arrangement density of 25 (pieces / square mm) in the non-display area 5 and a spacer arrangement density of 20 (pieces / square) in the display area 6. mm).

  The amount of bending of the substrate in the non-display area 5 changes smaller than the amount of bending of the substrate in the display area 6 according to the amount of liquid crystal to be sealed, and the amount of liquid crystal cannot be controlled to an appropriate area, thereby preventing the occurrence of display spots. I could not. The results are shown in the table of FIG.

  The present invention can be applied to a flexible liquid crystal display element, can control the amount of liquid crystal within an appropriate region, and can prevent generation of bubbles and display spots.

5 Non-display area 6 Display area 10 Liquid crystal display element 11 First substrate 12 Second substrate 13 Liquid crystal layer 14 Seal member 15 in a substantially rectangular frame shape Spacer

Claims (6)

A pair of substrates, at least one of which is flexible;
A liquid crystal layer sealed between the pair of substrates,
A region where one of the pair of substrates and the liquid crystal layer is in contact is divided into a display region and a non-display region,
The display area includes a plurality of spacers arranged between the pair of substrates and holding a gap between the pair of substrates,
In the non-display area, an area without a spacer is provided,
The liquid crystal display element, wherein an average cell gap of the non-display area is smaller than an average cell gap of the display area.   2. The liquid crystal display element according to claim 1, wherein a spacer is provided on the seal region side in the non-display region, and a region not provided with the spacer is provided on the display region side.   2. The space between the pair of substrates in the sealing region is wider than the space between the pair of substrates in the display region in the region not provided with the spacer in the non-display region. Liquid crystal display element.   In the non-display area, a spacer is disposed on the seal area side, and an area not provided with the spacer is provided on the display area side. The liquid crystal display element according to claim 1, wherein an interval between the pair of substrates in the seal region is made wider than an interval between them.   5. The liquid crystal display element according to claim 1, wherein a deflection amount of the substrate in the non-display area is larger than a deflection amount of the substrate in the display area.   6. The non-display area according to claim 1, wherein the average cell gap changes according to an amount of liquid crystal sealed and does not exceed the average cell gap of the display area. A liquid crystal display element according to 1.