JP2005258137A - Liquid crystal display panel and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display panel which can eliminate defective display due to a spacer and secure a large tolerance in cell gaps when assembling the panel and has a liquid crystal layer which is evenly thick and to provide its manufacturing method. <P>SOLUTION: Bead spacers 3 are used as the spacer to determine the thickness of the liquid crystal layer and arranged only between the pixel 14 and the pixel 14. Walls are formed on the substrate 1b on which the bead spacers 3 are arranged and that at the boundaries between the pixel 14 and a black matrix 15 to prevent the beads spacer 3 from moving into the pixel 14. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display panel and a manufacturing method thereof.

The liquid crystal display panel 9, as shown FIG 12, a TFT (T hin F ilm T ransistor ) substrate 1a formed with the transistors 16, red, blue, CF forming a green color (C olor F ilter) and the substrate 1b In this structure, the liquid crystal 5 is sandwiched between the spacers 3 and the substrates 1a and 1b are surrounded by a sealing material and bonded and fixed. In addition, 2 is an overcoat film, 14 is a color pixel, 15 is a black matrix (hereinafter referred to as “BM”), FIG. 9A is a top view seen from the spacer 3, and FIG. It is AA 'sectional drawing in the figure (a).

  In the liquid crystal display panel 9, an interval 10 (hereinafter referred to as “cell gap”) between the two substrates 1a and 1b in which the liquid crystal 5 is sealed is an important factor that determines display quality. In particular, the absolute dimension of the cell gap 10 and the uniformity of the cell gap 10 over the entire surface of the liquid crystal display panel 9 are important.

  Therefore, in the liquid crystal display panel 9 having such a configuration, in order to keep the distance between the two substrates constant, spherical transparent particle spacers 3 (hereinafter referred to as “bead spacers”) made of glass or synthetic resin having a uniform particle size. Is generally used by spreading between the substrates 1a and 1b.

  However, in the liquid crystal display panel using beads spacers dispersed on the substrate, the assembly work is performed after many beads spacers are dispersed on the substrate, so the beads spacers spill out during production and become particles that contaminate the production line. In addition to liquid crystal display panels that have been assembled, if a bead spacer is included in the display pixel together with the liquid crystal in the display pixel, there is no liquid crystal in the bead spacer portion. For example, when transparent particles are used for the bead spacer, when the liquid crystal display panel is set to black display, only the bead spacer portion becomes a bright spot. In addition, the alignment of the liquid crystal molecules in the vicinity of the bead spacer is disturbed, and light leakage occurs in this portion, which causes a problem that the contrast of the liquid crystal display panel is lowered and the display quality is adversely affected.

  Also, if the bead spacer moves from the initial spray position when assembling the two substrates or sealing the liquid crystal, the alignment film is damaged and the liquid crystal alignment is controlled in this area. Therefore, there is a problem that the display quality of the display panel is adversely affected as described above.

  Furthermore, as shown in FIG. 13, the CF substrate 1b used in the liquid crystal display panel is almost always not the same in thickness. This may occur unavoidably in manufacturing the red, green, and blue color pixel portions, or may change the film thickness of each color pixel portion in order to display an optimal color. For example, the bead spacers 3 dispersed on the green pixel portion 14G are in contact with and fixed to the two substrates 1a and 1b, but the bead spacers 3 dispersed on the red pixel portion 14R and the blue pixel portion 14B are Since there is an interval between the other substrate 1a, the fixing force of the bead spacer 3 is weak, and the bead spacer 3 moves due to vibration or the like. Even in such a case, the alignment film is scratched during the movement, and the liquid crystal alignment is not controlled in this portion, so that the display quality of the display panel is adversely affected as described above.

  As a method for preventing such movement of the bead spacer, as disclosed in Patent Document 1 below, a solvent in which a spacer member is mixed in an alignment agent is formed on a substrate, and the substrate is dried and baked to form a spacer. As described in Patent Document 2 below, a method of fixing with an aligning agent, and after applying an aligning agent on a substrate, the aligning agent is sprayed on the spacer substrate without solidifying, and then the aligning agent is solidified to form a spacer. In addition, as described in Patent Document 3 below, a spacer coated with a hot melt type adhesive or an epoxy adhesive is sprayed on the substrate, and then solidification treatment such as heating is performed to fix the spacer. A method has been proposed.

  However, although these methods can suppress the movement of the spacers, the spacers are disposed in the pixel portion, so that there is no effect of suppressing display defects due to light leakage due to the spacers or abnormal alignment around the spacers.

  As a technique for solving this, as shown in FIG. 14, a method of providing a columnar spacer 4 in a non-display area portion 15 (BM coating portion) between the pixel portion 14 and the pixel portion 14 on the CF substrate 1b is disclosed in the following patent. Suggested in references 4 and 5.

  This columnar spacer 4 is generally applied by applying a photosensitive resin serving as a spacer on a substrate while adjusting the thickness to a predetermined thickness by spin coating, slit coating, printing, or the like. A photomask having a convex shape is used, and the photosensitive resin is exposed through the photomask using an exposure light source. Thereafter, development processing is performed, and the photosensitive resin applied to the portion not to be the spacer is removed, the developer adhering to the substrate is washed, and the substrate is dried to form a convex spacer on the substrate.

  Since the columnar spacer manufactured by such a method can be placed at any position in the BM coating part between the pixel part that does not affect the display quality, there is a problem with the bead spacer. It is possible to prevent the display quality from being deteriorated due to light leakage from the columnar spacer portion. However, since the thickness of the liquid crystal layer (the distance between the two substrates) that affects the display quality is determined by the height of the columnar spacer, a photosensitive resin is used when manufacturing the columnar spacer in order to make the thickness of the liquid crystal layer uniform. It is necessary to make the coating film thickness uniform over the entire surface of the substrate and match the film thickness with the target value.

  However, in the actual photosensitive resin material application process, due to changes in the viscosity of the material, variations in shrinkage during drying, variations in shrinkage due to variations in exposure, etc. It is very difficult to form columnar spacers with small variations.

  Further, the columnar spacer 4 manufactured using the photolithography method has a limit in minimizing the diameter because of the manufacturing method. For example, when a liquid crystal display panel having a cell gap of 4 μm is manufactured, a bead spacer 3 having a diameter of 4 μm is used in a liquid crystal display panel using the bead spacer 3, whereas a columnar spacer is used in a liquid crystal display panel using the columnar spacer 4. Even if the height of 4 is 4 μm, the diameter is generally 15 μm to 30 μm as shown in FIG. 15 (c).

  Even when a normal liquid crystal panel has a volume expansion of the liquid crystal due to a temperature change in the use environment or a panel temperature increase due to a backlight, the thickness of the liquid crystal layer needs to be uniform over the entire panel surface due to the action of the spacer. Therefore, at the time of manufacturing the liquid crystal display panel, it is general to assemble the spacer so that the spacer is elastically deformed as shown in FIGS. 15B and 15D in consideration of the volume expansion of the liquid crystal due to this temperature change. Is.

As shown in FIG. 15, in the bead spacer 3 and the columnar spacer 4, the stress and strain of the spacer itself have a relationship as shown in FIG. 16 due to the difference in diameter and tip shape. This indicates that when the same stress is applied, the range of elastic deformation is wider in the bead spacer 3 than in the columnar spacer 4, and the range in which the spacer functions normally is wide. The deformation amount of the bead spacer = H _B −h _b , the deformation amount of the columnar spacer = H _F −h _f , and the maximum spacer deformation amount in the elastic deformation region: T2> T1.

From the above results, as shown in FIG. 17, the bead spacer 3 and the columnar spacer 4 have different maximum deformation amounts (T2> T1) in the elastic deformation region that functions normally. In the liquid crystal display panel used, it can be said that the liquid crystal display panel using the bead spacer 3 has a wider product tolerance with respect to a temperature change (M2> M1) from normal temperature (MB). Therefore, from the viewpoint of assembling the liquid crystal layer uniformly, it can be said that the liquid crystal display panel using the bead spacer is easier to manufacture.
JP-A-60-262129 JP-A-61-2129 JP-A-4-243230 JP 61-173222 A US Pat. No. 5,963,288

  In the liquid crystal display panel of the background art, spherical bead spacers are dispersed over the entire surface of the substrate to determine the thickness of the liquid crystal layer sealed between the two substrates, and the cell gap is determined by the bead spacers. And a method in which columnar spacers are formed by photolithography using a photosensitive resin in a portion that does not affect display quality between the pixel portion and the pixel portion on the substrate in advance. Is mainly used.

  Liquid crystal display panels using bead spacers are easier to make than methods using columnar spacers, but bead spacers are also placed in the pixel area. There is a problem that display defects such as the above occur.

  On the other hand, in a liquid crystal display panel using columnar spacers, the columnar spacers can be arranged at arbitrary positions, so that the portion other than the display area that does not affect the display quality between pixels is usually In addition, since it is generally arranged on the BM formed around the display area, it is possible to suppress the occurrence of display failure due to light leakage of the columnar spacer portion.

  However, it is very difficult to manufacture columnar spacers having a uniform height over the entire surface of the substrate and high dimensional accuracy due to the characteristics of the manufacturing method. Also, when manufacturing a liquid crystal display panel using a substrate on which this columnar spacer is formed, the diameter of the columnar spacer is larger than that of the bead spacer, and the shape of the tip is flat, so that the range of good quality of spacer deformation is good. However, there is a problem that it is difficult to manufacture as compared with a method using a bead spacer.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display panel that does not cause display defects such as light loss and has a wide range of good products when assembling a liquid crystal display panel by a spacer that determines the thickness of a liquid crystal layer, and a manufacturing method thereof That is.

  In the liquid crystal display panel of the present invention, the spacer that determines the distance between the TFT substrate and the CF substrate that affects the display quality is disposed only at a position other than the display region between the pixel portion and the pixel portion. In order to make such an arrangement, the surface of the bead spacer is coated with an adhesive whose adhesive strength is reduced by irradiating the surface of the bead spacer. By irradiating ultraviolet rays, the adhesive strength of the bead spacers is reduced, and then the entire surface of the substrate is washed to remove only the bead spacers scattered on the pixel portion where the adhesive strength of the bead spacers has been reduced. The bead spacers are arranged only at the positions.

  Further, as another aspect, instead of coating the bead spacer with an adhesive whose adhesive strength is reduced by irradiating ultraviolet rays, the bead spacer is spread on the substrate on which the bead spacer is spread before or after the bead spacer is spread. Apply adhesive at both timings, and then reduce the adhesive strength of the bead spacers by irradiating UV light to the part other than the part where the bead spacers are to be left, and then wash the entire surface of the substrate, Only the bead spacers scattered on the pixel portion where the adhesive force is reduced are removed.

  Furthermore, as another aspect, the bead spacers arranged between the pixel units move to the display pixels when the liquid crystal display panel is assembled, the liquid crystal display panel is handled or used, and the display quality is increased. In order to prevent the bead spacer from moving into the display pixel, a partition wall is provided at the boundary between the effective pixel portion and the non-pixel portion (BM).

  In this way, a bead spacer is used as a spacer for determining the cell gap, and the bead spacer is arranged only in a display area other than the display area between the pixel portion, thereby displaying due to an orientation abnormality caused by the bead spacer. Defects can be suppressed.

  In addition, bead spacers that are arranged only outside the display area between the pixel units move into the display pixels during assembly and handling of the liquid crystal display panel and during use of the liquid crystal display panel, thereby causing orientation abnormalities. It is possible to suppress an abnormal alignment of the display pixel portion due to the bead movement by disposing the partition wall for preventing the bead spacer movement at the boundary between the effective pixel portion and the non-pixel portion (BM).

  As described above, in the present invention, the bead spacer that determines the distance between the TFT substrate and the CF substrate that affects the display quality is disposed only at a position (BM portion) other than the display region between the pixel portion and the pixel portion. By adopting such a configuration, it is possible to suppress display defects due to light leakage or orientation abnormality caused by the bead spacer.

  In addition, bead spacer movement prevention is provided so that bead spacers placed only outside the display area between the pixel portions do not move into the display pixels during assembly, handling, and use of the liquid crystal display panel. By disposing the partition wall at the boundary between the effective pixel portion and the non-pixel portion (BM), the movement of the bead spacer is suppressed, and the display failure due to the light leakage or the alignment abnormality caused by the bead spacer can be suppressed.

  In addition, the spacer that determines the thickness of the liquid crystal layer of the liquid crystal display panel uses a bead spacer, so the thickness of the liquid crystal layer is uniform, and the good product tolerance range of the cell gap when assembling the liquid crystal display panel is widened. It is possible to manufacture a quality liquid crystal display panel with a high yield.

  Examples of the present invention will be described below.

  Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view showing an embodiment of a liquid crystal display panel according to the present invention, and FIGS. 2A and 2B are a plan view and a sectional view showing a liquid crystal display element (CF substrate side) according to the present invention. .

  A liquid crystal display panel 9 manufactured by using the present invention includes a TFT substrate 1a on which transistors are formed, a CF substrate 1b on which red, blue, and green colors are formed under the overcoat film 2, and these two substrates in a predetermined manner. It is mainly composed of a bead spacer 3 for adjusting the interval, a partition wall 6 having a function of preventing the movement of the bead spacer 3, and a liquid crystal 5. Although omitted in the drawing, the two substrates 1a and 1b are fixed and the liquid crystal is fixed. The liquid crystal 5 in the display panel 9 is constituted by a sealing material having a function of preventing the liquid crystal 5 from overflowing to the periphery.

  In the present invention, the bead spacer 3 is used as a spacer for defining the thickness of the liquid crystal layer. The bead spacers 3 are disposed only between the partition walls 6 that serve to prevent the movement of the bead spacers 3 formed on the BM 15, and do not exist on the pixel portion 14.

  First, with reference to FIG. 3, an example of a manufacturing method in the case where the partition wall 6 having the function of preventing the movement of the bead spacer 3 is manufactured using a photolithography method will be described below.

  1) A photosensitive resin 20 serving as a partition wall is applied on the CF substrate 1b while adjusting the thickness to a predetermined thickness by spin coating, slit coating, printing, or the like (FIG. 3A).

  2) Using the photomask 21a in which the partition wall 6 has a convex shape on the CF substrate 1b, the photosensitive resin film 20 is exposed using the exposure light source 22 over the photomask 21a (FIG. 3B). )).

  3) The developing process is performed to remove the photosensitive resin 20 applied to the portion not to be the partition wall 6 (FIG. 3C).

  4) The developer attached to the CF substrate 1b is washed away, and the CF substrate 1b is dried. (FIG. 3 (d)). Through the above steps, the partition wall 6 is formed on the CF substrate 1b so as to prevent the bead spacer 3 from moving.

  In the present description, the CF substrate 1b is used as the substrate for forming the partition wall. However, when the substrate is combined, the partition wall is disposed at a position between the pixel portion and the pixel portion (BM portion). As shown in FIG. 9, the effect is the same even if the substrate on which the partition wall 6 is disposed is a TFT-side substrate 1a.

  Next, as shown in FIG. 4, an example of a manufacturing method in the case where the partition wall 6 is manufactured using an etching method will be described below.

  1) A resin material 19 to be a partition wall 6 is applied on the CF substrate 1b while adjusting the thickness to a predetermined thickness by spin coating, slit coating, printing, or the like, and prebaked to dry the resin material 19 (FIG. 4 ( a)).

  2) A photosensitive resin such as a positive resist 18 is applied on the resin material 19 to be the partition walls 6 by spin coating, slit coating, printing, or the like, as described above (FIG. 4B).

  3) The positive resist 18 is exposed by using a photomask 21b in which the partition wall has a convex shape on the CF substrate 1b and using the exposure light source 22 through the photomask 21b (FIG. 4C).

  4) Development of the positive resist 18 and etching treatment of the resin material 19 to be the partition wall 6 are performed using an alkali developer, and the positive resist 18 and the resin material 19 applied to the portion not to be the partition wall 6 are removed (FIG. 4). (d)).

  5) The positive resist material 18 remaining on the material of the partition wall 6 is peeled off, the resist stripping solution adhering to the CF substrate is washed away, and the CF substrate 1b is dried (FIG. 4E). Through the above steps, the partition walls 6 are formed in a convex shape on the substrate 1b.

  The feature of this method is that it is excellent in forming a fine pattern as compared with the photolithography method, so that the curvature of the edge portion of the partition wall that serves to prevent the movement of the manufactured bead spacer can be reduced.

  In this description, the CF substrate 1b is used as the substrate on which the partition wall is formed. However, when the substrate is combined, the partition wall 6 is disposed at a position between the pixel portion and the pixel portion (BM portion). As shown in FIG. 9, the same effect is obtained when the substrate on which the partition wall 6 is arranged is a TFT-side substrate 1a.

  In addition to the above method, a photosensitive resin film or a thermosetting resin is applied directly on the substrate using a printing method so that the partition wall that functions to prevent the movement of the bead spacers has a convex shape, and then a predetermined post-treatment is performed. There is also a method of forming a shape by applying and curing.

  In the above description, the number of partition walls 6 formed between the pixel portion 14 and the pixel portion 14 has been described as two. However, as shown in FIG. If the space which can arrange | position can be ensured, of course, the number of the partition 6 may be two or more.

  Next, as shown in FIG. 5, when a liquid crystal display panel is manufactured using a substrate 1b in which a partition wall 6 is formed on a BM 15, beads having a function for setting a distance between two substrates to a predetermined value. A method of disposing only between the partition walls 6 having the function of preventing the movement of the spacer will be described.

For the bead spacer used in the present invention, a surface coated with an adhesive material is used. This pressure-sensitive adhesive has an adhesive strength of about 2.5 to 13.0 N / 25 mm in a normal state, but the pressure-sensitive adhesive is cured by irradiating ultraviolet light of about 500 to 1000 mJ / cm ² here. A material whose adhesive strength is reduced to 0.1 to 0.4 N / 25 mm or less.

  Examples of adhesives having such functions include acrylic adhesives used in the dicing UV tape UC series manufactured by Furukawa Electric Co., Ltd. and dicing self-peeling manufactured by Sekisui Chemical Co., Ltd. Candidates include pressure-sensitive adhesives used in mold-type adhesive tapes.

  Hereinafter, a method of arranging the bead spacer 3 only between the partition walls 6 will be described with reference to FIG.

  1) The bead spacers 3 coated with the adhesive 13 are spread over the entire surface of the CF substrate 1b. As a spraying method of the bead spacer 3, spraying may be performed on the entire surface of the CF substrate 1b by using a spray nozzle, or by spraying in the vicinity of or between the partition walls 6 formed on the BM 15 by using an ink jet or the like. May be. In this state, the bead spacer 3 is 2.5 to 13.0 N / 25 mm with respect to the CF substrate 1 b (N / 25 mm is a notation method representing the adhesive strength (adhesive strength) determined by JIS Z-0237 or the like). It is adhered with a strength of about a value when the width of the test piece is 25 mm. (Fig. 5 (a))

  2) A photomask 21c patterned so that light is shielded only between the partition walls 6 formed on the BM 15 is fixed in alignment with the CF substrate 1b, and an exposure light source 22 is passed through the photomask 21c. Irradiate with ultraviolet light. (Fig. 5 (b))

  3) By washing the entire surface of the CF substrate 1b with a cleaning solution 23 such as pure water, the bead spacers 3 whose adhesive strength with the CF substrate 1b has been reduced by the irradiation of ultraviolet rays are washed away. That is, the bead spacers 3 scattered between the partition walls 6 formed on the BM 15 remain. (Fig. 5 (c))

  4) The entire surface of the CF substrate 1b is again irradiated with ultraviolet rays using the exposure light source 22, and the pressure-sensitive adhesive 13 on the surface of the bead spacers 3 distributed between the partition walls 6 is cured. In order to prevent the liquid crystal display panel from being contaminated by the components of the pressure-sensitive adhesive 13 and thus causing a display defect when the liquid crystal display panel is produced without the pressure-sensitive adhesive 13 being cured. Is what you do. Note that this treatment can be omitted if the adhesive 13 is a material that does not cause liquid crystal contamination even when it is not cured. Further, when it is necessary to minimize damage to the pixel portion 14 due to ultraviolet irradiation, the effect is the same even if ultraviolet rays are irradiated through the photomask 21d. (Fig. 5 (d))

  Next, using FIG. 6, the adhesive 13 is not coated on the bead spacer 3 but the adhesive 13 is applied to the CF substrate on which the partition wall 6 having the function of preventing the movement of the bead spacer 3 is formed. Thus, a method for arranging the bead spacers 3 only between the partition walls 6 formed on the BM 15 will be described.

  1) First, the adhesive 13 is applied to a predetermined thickness by spin coating, slit coating, printing, or the like. (Fig. 6 (a))

  2) The bead spacers 3 are spread over the entire CF substrate 1b. As a method for spraying the bead spacers 3, spray beads may be sprayed on the entire surface of the CF1b substrate, or may be selectively used in the vicinity of or between the partition walls 6 formed on the BM 15 by using an inkjet or the like. It may be sprayed. In this state, the bead spacer 3 is bonded to the CF substrate 1b with a strength of about 2.5 to 13.0 N / 25 mm. (Fig. 6 (b))

  3) A photomask 21c patterned so that light is shielded only between the partition walls 6 formed on the BM 15 is fixed to the CF substrate 1b in alignment, and the exposure light source 22 is passed through the photomask 21c. Irradiate with ultraviolet rays. (Fig. 6 (c))

  4) By washing the entire surface of the CF substrate 1b with a cleaning solution 23 such as pure water, the bead spacers 3 whose adhesive strength with the CF substrate 1b has been reduced by the irradiation of ultraviolet rays are washed away. That is, the bead spacers 3 dispersed between the partition walls 6 formed on the BM 15 are left. (Fig. 6 (d))

  5) The UV light source 22 is used to irradiate the entire surface of the CF substrate 1b again or the portion where the UV light is not irradiated and the pressure-sensitive adhesive is not cured in the previous process, and the pressure-sensitive adhesive 13 in the remaining portion is cured. Also in this process, when a liquid crystal display panel is produced in a state where the adhesive 13 is not cured, the components of the adhesive 13 cause contamination of the liquid crystal, thereby preventing display defects. Is what you do. Note that this treatment can be omitted if the adhesive 13 is a material that does not cause liquid crystal contamination even when it is not cured. When it is necessary to minimize damage to the pixel portion 14 due to ultraviolet irradiation, the effect is the same even if ultraviolet rays are irradiated through the photomask 21d. (Fig. 6 (e))

  In FIG. 6, the adhesive 13 is applied to the substrate 1b before the bead spacer 3 is spread over the entire CF substrate 1b. However, after the bead spacer 3 is spread over the entire CF substrate 1b, the adhesive 13 is applied to the substrate 1b. An example of application is shown in FIG. Moreover, the example which apply | coats the adhesive 13 before spraying the bead spacer 3 after spraying is shown in FIG. The other steps in FIGS. 7 and 8 are the same as those in FIG. Therefore, the adhesive 13 may be applied at any one or both before and after the bead spacers 3 are dispersed.

  In the above description, the description has been made on the assumption that the partition wall 6 is formed on the CF substrate 1b. However, as shown in FIG. 9, when the liquid crystal display panel 9 is assembled, the pixel portion 14 and the pixel portion 14 face each other. If the partition wall 6 is formed at such a position, the same effect can be obtained even if the partition wall 6 is formed on the TFT substrate 1a side.

  As described above, the bead spacers are arranged outside the display area and between the partition walls that serve to prevent the movement of the bead spacers, and the two substrates are assembled to complete the liquid crystal display panel.

  As a manufacturing method for manufacturing a liquid crystal display panel using the substrate, two methods of a vacuum injection method and a drop injection method have been proposed. The vacuum injection method is a method in which liquid crystal is injected into a space provided between the TFT substrate and the CF substrate after the TFT substrate and the CF substrate are assembled via a spacer. In contrast, the dropping injection method is a method in which a predetermined amount of liquid crystal is dropped on one of the TFT substrate and the CF substrate, and then the other substrate is overlapped to assemble a liquid crystal display panel and inject liquid crystal at the same time.

  The partition formed on the BM prevents the bead spacer from moving from the initial spray position when the TFT substrate and CF substrate are assembled, when liquid crystal is injected into the space of the TFT substrate and CF substrate, and when the liquid crystal display panel is used. Have work. Therefore, the height of the partition formed on the BM may be a height at which the bead spacer does not move in these states. The height of the partition differs depending on the method of manufacturing the liquid crystal display panel and the method of forming the partition (the shape of the corner of the partition). The result of the confirmation experiment is shown in FIG.

  When a liquid crystal display panel is manufactured by a vacuum injection method, first, a TFT substrate and a CF substrate are overlaid, and a gap is created to create an empty liquid crystal display panel that does not contain liquid crystal. Liquid crystal is injected from the liquid crystal injection port provided in the section using capillary action and pressure difference. The liquid crystal injection method using the pressure difference is a vacuum atmosphere by evacuating the empty space inside the liquid crystal display panel where the overlapping and gap formation is completed, and then the inlet is brought into contact with the liquid crystal so that the periphery of the liquid crystal display panel The liquid crystal is injected into the liquid crystal display panel using the pressure difference between the inside and outside of the liquid crystal display panel by returning the pressure to atmospheric pressure or increasing the pressure.

  In this assembly method, when the liquid crystal is injected, since the bead spacer is always sandwiched and pressurized by the TFT substrate and the CF substrate, the bead spacer hardly moves. Possible movement of the bead spacer may be when the TFT substrate and the CF substrate are overlapped, when a gap is formed, when the panel is deformed, such as when a liquid crystal panel is used, or when the volume of liquid crystal is expanded by heat.

  As a result of the experiment shown in FIG. 10, in the case of a liquid crystal display panel manufactured by a vacuum injection method, almost no bead movement was observed if the height of the partition wall was about 30% or more of the diameter of the bead spacer. In the etching method, 20% or more is sufficient.

  In contrast, when a liquid crystal display panel is manufactured by the dropping injection method, first, a prescribed amount of liquid crystal is dropped on either the TFT substrate or the CF substrate, and this substrate is overlaid in a vacuum atmosphere to create a gap. The liquid crystal is injected and assembled at the same time. In the case of this assembly method, when the liquid crystal display panel is assembled, the bead spacer may be moved when the liquid crystal dropped on the substrate wets and spreads over the entire surface of the substrate.

  As a result of the experiment shown in FIG. 10, when the height of the partition wall is about 70% or more of the diameter of the bead spacer, the movement of the bead spacer during assembly was hardly observed. In the etching method, 60% or more is sufficient.

  As described above, according to the present invention, it is possible to freely select an arrangement position of the bead spacer by using the pressure-sensitive adhesive whose adhesive strength is reduced by irradiating ultraviolet rays. In addition, two or more partition walls are arranged at a position (BM part) other than the display area between the pixel part of the liquid crystal display panel and the bead spacers are arranged between the partition walls, thereby providing a liquid crystal display panel. It is possible to suppress movement into the display pixel during assembly, handling, and use.

Sectional drawing which shows the structure of the liquid crystal display panel which concerns on this invention The top view and sectional drawing which show the structure of the liquid crystal display panel which concerns on this invention Process diagram for manufacturing barrier ribs by photolithography Process chart for manufacturing partition walls by etching method Process diagram of placing bead spacers coated with adhesive between partition walls Process diagram for arranging bead spacers between partitions coated with adhesive Process diagram of placing bead spacers between partition walls by applying adhesive after spraying bead spacers Process diagram of placing bead spacers between partition walls by applying adhesive before and after spreading bead spacers Sectional drawing of the liquid crystal display panel which shows the other Example of this invention. The figure showing the relationship between the manufacturing method of a liquid crystal display panel and the height of a partition The top view and sectional drawing of the liquid crystal display element which show the other Example of this invention. A perspective view and a sectional view showing a structure using a bead spacer in a conventional liquid crystal display panel A perspective view and a sectional view showing a structure using a bead spacer in a conventional liquid crystal display panel with a pixel step. A perspective view and a cross-sectional view showing a structure using columnar spacers in a conventional liquid crystal display panel with pixel steps Sectional view showing spacer deformation Stress-strain diagram of spacer Graph showing the relationship between spacer deformation and liquid crystal display panel temperature

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a ... TFT substrate, 1b ... CF substrate, 2 ... Overcoat film, 3 ... Bead spacer, 4 ... Columnar spacer, 5 ... Liquid crystal, 6 ... Partition, 9 ... Liquid crystal display panel, 13 ... Adhesive, 14 ... Color pixel, 15 ... BM, 16 ... TFT, 18 ... Positive resist, 19 ... Resin material, 20 ... Photosensitive resin, 21 ... Photomask, 22 ... Light source for exposure

Claims (10)

  In a liquid crystal display panel having a pair of substrates sandwiching a liquid crystal, a bead spacer is attached to a portion other than the display region between the pixel portion so that the distance between the pair of substrates is a predetermined interval. A liquid crystal display panel characterized by being arranged via   The liquid crystal display panel according to claim 1, wherein the pressure-sensitive adhesive is a pressure-sensitive adhesive whose adhesive strength decreases when irradiated with ultraviolet rays.   2. The liquid crystal display panel according to claim 1, wherein convex partition walls are formed in a portion other than the display region by a photolithography method or an etching method.   The liquid crystal display panel according to claim 1, wherein a black matrix is formed in a portion other than the display region and around the display region.   The liquid crystal display panel according to claim 1, wherein two or more convex partition walls are formed in a portion other than the display area.   The liquid crystal display panel according to claim 1, wherein bead spacers are disposed only between two or more convex partition walls disposed in a portion other than the display area. Adhesive strength is reduced by irradiating only a portion other than the display region between the pixel portion with the bead spacer so that the distance between the pair of substrates holding the liquid crystal becomes a predetermined interval. In the manufacturing method of the liquid crystal display panel arranged via the adhesive,
After the adhesive is coated on the surface of the bead spacer and the bead spacer is dispersed on the entire surface of the substrate, the bead spacer is disposed only in a portion other than the display region by removing only the bead spacer disposed in the pixel portion. A method for producing a liquid crystal display panel.   The removal of only the bead spacers arranged in the pixel part is performed by irradiating UV light to a part other than the part where the dispersed bead spacers are to be left, thereby reducing the adhesive force of the bead spacers, and then cleaning the entire surface of the substrate. 8. The method of manufacturing a liquid crystal display panel according to claim 7, wherein only the bead spacers with reduced adhesive strength are removed. Adhesion that reduces the adhesive force by irradiating only the part other than the display area between the pixel part and the bead spacer so that the distance between the pair of substrates holding the liquid crystal becomes a predetermined distance. In the manufacturing method of the liquid crystal display panel arranged through the agent,
Before or after spraying the bead spacer on the substrate on the side where the bead spacer is sprayed, or after applying the adhesive, by removing only the bead spacer arranged in the pixel portion, A method for manufacturing a liquid crystal display panel, wherein bead spacers are arranged only in a portion other than a display region. The removal of only the bead spacers arranged in the pixel part is performed by irradiating UV light to a part other than the part where the dispersed bead spacers are to be left, thereby reducing the adhesive force of the bead spacers, and then cleaning the entire surface of the substrate. 10. The method of manufacturing a liquid crystal display panel according to claim 9, wherein only the bead spacers with reduced adhesive strength are removed.

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