JP2019158904A - Liquid crystal display device and method for manufacturing the same - Google Patents

Abstract

To achieve a flexible liquid crystal display device with a hardly recognizable frame region.SOLUTION: The liquid crystal display device has a liquid crystal 300 held between a first substrate 100 and a second substrate 200, in which the first substrate 100 and the second substrate 200 are formed of flexible substrates, a columnar spacer 20 is formed in a display region between the first substrate 100 and the second substrate 200, and an outer wall 21 is formed in the periphery of the first substrate 100 and the second substrate 200. The columnar spacer 20 and the outer wall 21 are formed of a material that develops adhesiveness by irradiation with UV rays or by heating, and the columnar spacer 20 and the outer wall 21 are adhered to the first substrate 100 side.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a display device, and more particularly to a liquid crystal display device that can be flexibly bent.

  In a liquid crystal display device, a TFT substrate in which pixel electrodes and thin film transistors (TFTs) are formed in a matrix and a counter substrate are arranged opposite the TFT substrate, and a liquid crystal layer is sandwiched between the TFT substrate and the counter substrate It has a liquid crystal display panel. An image is formed by controlling the light transmittance of the liquid crystal molecules for each pixel.

  If the distance between the TFT substrate and the counter substrate varies, the layer thickness of the liquid crystal varies, causing uneven brightness and uneven colors. For this reason, usually, a columnar spacer is formed on the counter substrate, and the distance between the TFT substrate and the counter substrate is kept constant by the columnar spacer. However, in a large liquid crystal display panel, when the liquid crystal display panel is used in a standing state, a phenomenon occurs in which liquid crystal accumulates in the lower part of the panel due to gravity, and the distance between the TFT substrate and the counter substrate changes.

  In order to prevent this, Patent Document 1 discloses that in order to make the distance between the TFT substrate formed of glass and the counter substrate constant, a columnar spacer is formed on one substrate, and the other substrate on which the columnar spacer contacts. An arrangement is described in which an adhesive is disposed on the other substrate so that the other substrate is not separated from the columnar spacer, thereby keeping the distance between the TFT substrate and the counter substrate constant.

  In Patent Document 2, a spacer and a sealing material are formed on one glass substrate on which an alignment film is formed, and the other glass substrate is heated after being stacked, so that both substrates are bonded together by the spacer and the sealing material, Thereafter, a configuration in which liquid crystal is injected from an opening opened in the sealing material is described.

  Patent Document 3 describes a configuration in which an adhesive layer is formed on a normal spacer formed on one glass substrate and bonded to the other glass substrate.

  Patent Document 4 describes a configuration in which an alignment film for FFS (Fringe-Field-Switching) is formed by irradiating a liquid crystal material with UV light instead of forming an alignment film by conventional coating.

JP 2011-65086 A JP 2003-330029 A JP 2004-12772 A WO2018 / 008581A1

  The distance between the TFT substrate and the counter substrate is maintained by columnar spacers. However, in order to stabilize the display quality of the liquid crystal display panel, it is important to maintain the distance between the TFT substrate and the counter substrate. It is necessary to be able to cope with the pressure, impact, temperature change, etc. For this reason, columnar spacers are formed between the TFT substrate and the counter substrate. However, if the repulsive force is too small, for example, because the number of columnar spacers formed is too small, the deformation becomes large when a pressing force is applied from the outside, and in an extreme case, it cannot be restored. In addition, if the repulsive force is too large because the number of columnar spacers formed is too large, bubbles may be generated inside the liquid crystal display panel when an impact is applied from the outside or when exposed to a different temperature environment. The phenomenon that occurs occurs. Such a phenomenon is particularly prominent when the TFT substrate and the counter substrate are hard substrates such as glass.

  On the other hand, in the liquid crystal display device, there is a demand to increase the area of the display region as much as possible while keeping the outer dimensions constant. However, since the TFT substrate and the counter substrate are usually bonded together by a sealing material at the periphery, if the width of the sealing material is made extremely small, the bonding strength between the TFT substrate and the counter substrate becomes insufficient.

  In addition, there is a demand for a liquid crystal display device to be flexibly used. When the liquid crystal display panel is used in a curved shape, not only the pressing pressure but also other pressures such as pulling and displacement act on the distance between the TFT substrate and the counter substrate. For bonding the counter substrate, a stronger bonding force is required.

  SUMMARY OF THE INVENTION An object of the present invention is to realize a liquid crystal display device which can be used while being curved, and which can maintain the spacing between substrates and adhesion more stably.

  The present invention overcomes the above problems, and specific means are as follows.

  (1) A liquid crystal display device in which liquid crystal is sandwiched between a first substrate and a second substrate, wherein the first substrate and the second substrate are formed of a flexible substrate, A columnar spacer is formed in a display area between the first substrate and the second substrate, an outer wall is formed at an end of the substrate between the first substrate and the second substrate, and the columnar spacer and the outer wall are formed. Is formed of a material that exhibits adhesiveness by ultraviolet irradiation or heating, and the columnar spacer and the outer wall are bonded to the first substrate side and both surfaces of the second substrate. .

  (2) A method of manufacturing a liquid crystal display device in which a liquid crystal is sandwiched between a first substrate and a second substrate, wherein the first substrate and the second substrate are formed of a flexible substrate, and the second substrate A photosensitive resin is formed on the substrate, and columnar spacers are simultaneously formed on the display area of the second substrate and an outer wall is formed on the peripheral portion of the second substrate by photolithography, and the first substrate and the first substrate are formed. 2. A method for manufacturing a liquid crystal display device, wherein the columnar spacer and the outer wall are made to exhibit adhesiveness by heating or irradiating ultraviolet rays when bonding the two substrates.

(3) A method of manufacturing a liquid crystal display device in which a liquid crystal is sandwiched between a first substrate and a second substrate, wherein the first substrate and the second substrate are formed of a flexible substrate, and the second substrate A photosensitive resin is formed on the first substrate, and columnar spacers are simultaneously formed on the display region of the second substrate and an outer wall is formed on the periphery of the second substrate by photolithography, and the first substrate is formed on the first substrate. Forming an alignment film of
When the first substrate and the second substrate are bonded, the columnar spacer and the outer wall are bonded to the first alignment film by heating or irradiating the columnar spacer and the outer wall with ultraviolet rays. A manufacturing method of a liquid crystal display device characterized by comprising:

It is a top view of a liquid crystal display device. It is AA sectional drawing of FIG. It is a top view of the display area of FIG. It is BB sectional drawing of FIG. It is a top view of the liquid crystal display device by Example 1 of this invention. It is CC sectional drawing of FIG. It is a top view of the display area of FIG. It is DD sectional drawing of FIG. It is sectional drawing which formed the TFT substrate on the glass substrate. It is sectional drawing of the state which formed the array layer and the adhesive material layer on the TFT substrate. It is sectional drawing of the state which formed the counter substrate on the glass substrate and formed the color filter layer and the overcoat film on it. It is sectional drawing of the state in which the photosensitive material for columnar spacers was formed on the overcoat film. It is sectional drawing of the state which formed the columnar spacer and the outer wall on the overcoat film by photolithography. It is sectional drawing of the state filled with the liquid crystal by ODF. It is sectional drawing which shows the state which bonded together the TFT substrate and the counter substrate. Sectional drawing which shows the state which has irradiated the laser beam for laser ablation. It is sectional drawing which shows the state which has peeled the glass substrate. 6 is a cross-sectional view showing a configuration of Example 2. FIG. FIG. 10 is a plan view of a display area in Example 2. It is EE sectional drawing of FIG. It is sectional drawing which shows the state which formed the alignment film on the array layer in a TFT substrate. FIG. 6 is a cross-sectional view showing a state where a columnar spacer and a photosensitive resin for an outer wall are formed on an overcoat film in the counter substrate. It is sectional drawing which shows the state which formed the alignment film after forming the columnar spacer by photolithography. It is sectional drawing which shows the state which has filled the liquid crystal with ODF on the counter substrate side. It is sectional drawing which shows the state which bonded together the TFT substrate and the counter substrate. It is sectional drawing which shows the state which has peeled the glass substrate. 6 is a cross-sectional view of a liquid crystal display device showing a configuration of Example 3. FIG. 6 is a cross-sectional view of a display area of Example 3. FIG. It is a top view of the seal part of a prior art example. It is a top view of the seal part by the present invention. It is sectional drawing which shows the state which curved the liquid crystal display device of the prior art example. It is sectional drawing which shows the state which curved the liquid crystal display device by this invention. It is an example of a liquid crystal display device having a special shape. It is another example of the liquid crystal display device with a special shape. It is an example of the liquid crystal display device with a special external shape. It is another example of the liquid crystal display device with a special outer diameter.

  The contents of the present invention will be described below using examples.

  FIG. 1 is a plan view showing an example of a general liquid crystal display device used for a smartphone or the like. In FIG. 1, the TFT substrate 100 and the counter substrate 200 are bonded by a sealing material 150, and the display region 40 is located in a region where the TFT substrate 100 and the counter substrate 200 overlap with each other and the liquid crystal is interposed between the TFT substrate 100 and the counter substrate 200. Is formed. The width sw1 of the sealing material 150 is, for example, about 0.8 mm, the end of the display area is further inside, and the distance from the end of the counter substrate to the end of the display area, that is, the frame width fw1 is For example, it is about 1.2 mm.

  The sealing material 150 is applied to the counter substrate 200 side with a dispenser, pressed against the TFT substrate 100, and cured after its shape is deformed. Therefore, it is difficult to accurately control the width sw1 of the sealing material 150.

  In the display area 40, scanning lines 91 extend in the horizontal direction (x direction) and are arranged in the vertical direction (y direction). The video signal lines 92 extend in the vertical direction and are arranged in the horizontal direction. A region surrounded by the scanning line 91 and the video signal line 92 is a pixel 93. The TFT substrate 100 is formed larger than the counter substrate 200, and a portion where the TFT substrate 100 and the counter substrate 200 do not overlap is a terminal region 50. The terminal area 50 is formed with terminals for connecting a flexible wiring board for supplying power, video signals, scanning signals and the like to the liquid crystal display panel.

  FIG. 2 is a cross-sectional view taken along the line AA of FIG. In FIG. 2, an array layer 101 including a semiconductor layer for forming a TFT, a scanning line, a video signal line, a pixel electrode, a common electrode, and the like is formed on the TFT substrate 100. The uppermost layer of the array layer 101 is a pixel electrode. On the array layer 101, an alignment film 103 for initial alignment of liquid crystal is formed.

  A color filter layer 201 including a black matrix is formed on the counter substrate 200. An overcoat film 202 is formed on the color filter layer 201. Columnar spacers 10 and 11 are formed on the overcoat film 202. An alignment film 203 is formed so as to cover the columnar spacers 10 and 11 and the overcoat film 201. In this case, since the alignment film 203 is formed only thinly on the columnar spacers 10 and 11 due to the leveling effect, the alignment film 204 on the columnar spacers 10 and 11 is not shown in FIG. . The same applies to the following drawings.

  In FIG. 2, the TFT substrate 100 and the counter substrate 200 are bonded together by a sealing material 150. Further, the liquid crystal 300 is sealed inside by the sealing material 150. The distance between the TFT substrate 100 and the counter substrate 200 is maintained by the columnar spacers 10 formed on the counter substrate 200. The columnar spacer includes a main columnar spacer 10 and a sub columnar spacer 11. In the normal state, the distance between the TFT substrate 100 and the counter substrate 200 is maintained by the main columnar spacer 10.

  In order to prevent the distance between the TFT substrate 100 and the counter substrate 200 from becoming excessively small when a pressing force is applied to the counter substrate 200 or the like, the sub-columnar spacer 11 is disposed. The sub-columnar spacer 11 is not normally in contact with the TFT substrate 100 side, but when the counter substrate 200 receives a pressing pressure from the outside, the sub-columnar spacer 11 contacts the TFT substrate 100 side and maintains the layer thickness of the liquid crystal 300. .

  In general, only the main columnar spacer 10 may be used without arranging the sub-columnar spacers 11 only for maintaining the distance between the substrates. However, when the substrate is made of a hard material such as glass, if only a large number of main columnar spacers 10 are provided, bubbles are generated in the liquid crystal layer due to the impact of returning the shape when a pressing force is applied to the substrate. End up. For this reason, the main columnar spacer 10 must be reduced as much as possible. If the number of main columnar spacers 10 decreases, the function of maintaining the distance between the substrates decreases. Therefore, in order to compensate for this, the sub columnar spacers 11 are provided. The sub-columnar spacer 11 has a gap with the TFT substrate 100, and the generation of bubbles can be suppressed by buffering the impact by the gap.

  In the sub columnar spacers 11, the number of sub columnar spacers 11 is larger than the number of main columnar spacers 10, and the diameter of the sub columnar spacers 11 is larger than the diameter 10 of the main columnar spacers. The diameter φ of the main columnar spacer 10 is, for example, 8 μm, and the diameter of the sub columnar spacer 11 is, for example, 11 μm. The number of sub columnar spacers 11 is, for example, 16 times the number of main columnar spacers 10.

  FIG. 3 is a plan view of a pixel portion in the display area 40 of the TFT substrate 100 of FIG. In FIG. 3, the scanning lines 91 extend in the horizontal direction and are arranged in the vertical direction. The video signal lines 92 extend in the vertical direction and are arranged in the horizontal direction. A region surrounded by the scanning line 91 and the video signal line 92 is a pixel 93, and a pixel electrode or the like exists inside the pixel 93. An alignment film 103 is formed on the entire surface of the TFT substrate 100 as shown in FIG.

  In FIG. 3, the main columnar spacer 10 and the sub columnar spacer 11 formed on the counter substrate 200 side are arranged at the intersection of the scanning line 91 and the video signal line 92. In the region shown in FIG. 3, only one main columnar spacer 10 exists. The sub columnar spacers 11 exist at the intersections with the scanning lines 91 every three video signal lines 92. The diameter of the main columnar spacer 10 is smaller than the diameter of the sub columnar spacer 11.

  4 is a cross-sectional view taken along line BB in FIG. In FIG. 4, an array layer 101 is formed on a TFT substrate 100, and an alignment film 103 is formed thereon. A color filter layer 201 is formed on the counter substrate 200, and an overcoat film 202 is formed thereon. A main columnar spacer 10 and a sub columnar spacer 11 are formed on the overcoat film 202. An alignment film 203 is formed on the overcoat film 202.

  A liquid crystal 300 is sandwiched between the TFT substrate 100 and the counter substrate 200. The distance between the TFT substrate 100 and the counter substrate 200 is defined by the main columnar spacer 10. In the state of FIG. 4, the sub columnar spacer 11 is not in contact with the TFT substrate 100 side. In FIG. 4, the diameter φs of the sub-columnar spacer 11 is larger than the diameter φm of the main columnar spacer 10. Here, the diameter of the columnar spacer 10 refers to a diameter φ at a position of 90% of the height h of the columnar spacer 10, as shown in the lower diagram of FIG. The same applies to the columnar spacers of the present invention shown in the following examples. A liquid crystal 300 is sandwiched between the TFT substrate 100 and the counter substrate 200.

  FIG. 5 is a plan view of a liquid crystal display device according to the present invention. 5 differs from FIG. 1 in that an outer wall 21 is formed around the TFT substrate 100 and the counter substrate 200 in order to seal liquid crystal. The outer wall 21 is made of the same material as the columnar spacer 20. That is, the columnar spacer 20 is formed by photolithography at the same time. The columnar spacer 20 and the outer wall 21 are formed of a material that exhibits adhesiveness by heating or ultraviolet irradiation. Therefore, since the TFT substrate 100 and the counter substrate 200 are bonded to both the columnar spacer 20 and the outer wall 21, the outer wall 21 is much smaller than the case of FIG. For example, it can be formed to a width of about 10 μm. Moreover, since the edge part of the outer wall 21 is also formed by photolithography, it can be controlled accurately.

  On the other hand, the sealing material 150 in FIG. 1 is applied to the counter substrate 200 side by a dispenser and is crushed when the TFT substrate 100 and the counter substrate 200 are bonded. Therefore, it is difficult to accurately control the width sw1 of the sealing material 150. Further, it is difficult to accurately control the end portion of the sealing material 150.

  Thus, in FIG. 5, coupled with the fact that the width sw2 of the outer wall 21 can be reduced, the frame width fw2 can be made significantly smaller than the frame width fw1 in FIG. For example, in FIG. 5, the frame width fw2 can be reduced to 0.1 mm or less, and the width of the outer wall can be reduced to about 0.05 mm.

  5 differs from FIG. 1 in that the TFT substrate 100 and the counter substrate 200 of FIG. 5 are formed of a resin substrate such as polyimide. As a result, the liquid crystal display panel can be flexibly bent. Further, as will be described later, all the columnar spacers 20 formed on the counter substrate 200 are in contact with the TFT substrate 100 side.

  That is, by forming the TFT substrate 100 and the counter substrate 200 with a flexible resin substrate, even if the number of the column spacers 20 is increased and the repulsive force is increased, the TFT substrate 100 and the counter substrate 200 are increased. Can be flexibly deformed to absorb the impact and prevent the generation of bubbles. Also, by adhering most of the columnar spacers 20 to the TFT substrate 100 side, the adhesive force between the TFT substrate 100 and the counter substrate 200 can be shared by the columnar spacers 20, and the adhesive force by the outer wall 21 can be reduced. The width of the outer wall 21 can be reduced, and as a result, the frame width fw2 can be kept very small.

  6 is a cross-sectional view taken along the line CC of FIG. In FIG. 6, an array layer 101 including a plurality of insulating layers and conductive layers such as pixel electrodes is formed on a TFT substrate 100. A color filter layer 201 including a black matrix is formed on the counter substrate 200, and an overcoat film 202 is formed thereon. Columnar spacers 20 are formed on the overcoat film 202. The outer wall 21 is formed of the same material as the columnar spacer 20 around the counter substrate 200. A liquid crystal 300 is sandwiched between the TFT substrate 100 and the counter substrate 200.

  In FIG. 6, the alignment film is not formed. In this case, an additive is added to the liquid crystal in order to align the liquid crystal in a specific direction. Some additives are used to align the liquid crystal vertically, and other additives are used to align the liquid crystal in a certain horizontal direction. The material of the additive is described in Patent Document 4, for example. When such a liquid crystal is sealed between the TFT substrate and the counter electrode, and then irradiated with polarized ultraviolet rays, a polymer layer having an alignment ability with respect to liquid crystal molecules in a predetermined direction is formed on the TFT substrate and the counter substrate. This aligns the liquid crystal.

  In FIG. 6, the columnar spacer 20 and the outer wall 21 are made of a material that exhibits adhesiveness by heating or ultraviolet irradiation. For this reason, the columnar spacer 20 and the outer wall 21 are bonded to the array layer 101, thereby bonding the TFT substrate 100 and the counter substrate 200 and defining the interval between the TFT substrate 100 and the counter substrate 200. Since the outer wall 21 in FIG. 6 is formed by photolithography at the same time as the columnar spacer 20, the width of the outer wall 21 can be reduced to about 10 μm, which is the same as the diameter of the columnar spacer 20. In other words, since only the outer wall 21 cannot maintain the adhesive force between the TFT substrate 100 and the counter substrate 200, the overall adhesive force can be improved by combining the adhesive force of the columnar spacers 20. Yes.

The evaluation of adhesive strength is as follows. When the liquid crystal display panel of FIGS. 1 and 5 is a 5-inch panel, the display area is 62.2 mm × 110.5 mm. In FIG. 1, when the width of the sealing material 150 is 0.8 mm, the area of the sealing material 150 is (62.2 × 0.8 + 110.5 × 0.8) = 276.32 mm ² . In FIG. 5, if the same adhesion area is provided by the columnar spacer 20, for example, the contact area ratio of the columnar spacer 20 is set to 4%. Then, the contact area of the columnar spacer 20 is 62.2 × 110.5 × 0.04 = 274.9 mm ² , which is substantially the same as the bonding area of the sealing material 150 in the case of FIG. Here, the contact area ratio of the columnar spacers 20 is that the area of the display region 40 is S, the area of the columnar spacers 20 at 90% of the height of the columnar spacers 20 is s, and the number of the columnar spacers 20 is n. In this case, s × n / S.

  In FIG. 5, in addition to the adhesion area of the columnar spacer 20, the adhesion force of the outer wall 21 is also applied, so that a larger adhesion area than in the case of FIG. 1 can be achieved. Considering the bonding area of the outer wall 21, the contact area ratio of the columnar spacers 20 should be larger than 1%, and more preferably 2% or more.

  Returning to FIG. 6, in the present invention, unlike FIG. 2, all the columnar spacers 20 formed on the counter substrate 200 are in contact with the TFT substrate 100 side. This is because the columnar spacer 20 has a bonding function between the TFT substrate 100 and the counter substrate 200. In the case of the glass substrate as shown in FIG. 2, when all the columnar spacers are formed by the main columnar spacers 10, bubbles are generated. However, in FIG. 6, since the TFT substrate 100 and the counter substrate 200 are formed of a flexible resin substrate, the TFT substrate 100 and the counter substrate 200 are deformed flexibly with respect to the repulsive force of the columnar spacers 20, so that the generation of bubbles can be suppressed. .

  Here, the meaning that all the columnar spacers 20 are brought into contact with the opposing substrate means that an adhesive force by the columnar spacers 20 is ensured. Therefore, it is not impeded to arrange the columnar spacers that do not contact the opposing substrate for some reason while securing the adhesive force. In this sense, bringing all the columnar spacers 20 in contact with the opposing substrate in this specification has the same meaning as bringing most of the columnar spacers 20 into contact with the opposing substrate. Here, the majority is, for example, 80% or more. On the other hand, the number of main columnar spacers 10 configured as shown in FIGS. 1 to 4 is 10% or less of the number of sub columnar spacers 11.

  In FIG. 6, the width of the outer wall 21 is equal to the diameter of the columnar spacer 20, but may be increased to, for example, about 0.1 mm in consideration of the mechanical strength of sealing the liquid crystal. . The width of the outer wall 21 can be set in accordance with the allowable frame width. Further, in consideration of the width of the outer wall 21, the contact area of the columnar spacer 20 can also be adjusted flexibly.

  FIG. 7 shows an arrangement example of the columnar spacers 20 in the present invention. 7 differs from FIG. 3 in that all the columnar spacers 20 have the same diameter, and are all in contact with the opposing substrate, that is, the TFT substrate 100 side.

  The diameter of the columnar spacer 20 in FIG. 7 is unified to the same diameter as the sub columnar spacer 11 in FIG. The diameter of the columnar spacer 20 may be determined in consideration of the number of the columnar spacers 20 and the width of the outer wall 21 from the viewpoint of securing adhesive force. In addition, the diameter of the columnar spacer 20 related to a specific color can be made different from the diameter of the columnar spacer 20 in other portions in terms of white brightness adjustment. That is, in the present invention, since bubbles do not become a big problem, the degree of freedom in determining the diameter of the columnar spacer 20 is great.

  8 is a cross-sectional view taken along the line DD of FIG. The cross-sectional configurations of the TFT substrate 100 and the counter substrate 200 in FIG. 8 are as described in FIG. In FIG. 8, all the columnar spacers 20 formed on the counter substrate 200 are directly bonded to the TFT substrate 100 side. If the adhesion area of each columnar spacer 20 can be measured with a cross-sectional shape as shown in FIG. 8, the area where the columnar spacer 20 is in contact with the array layer 101 may be measured. When the counter substrate 200 is disassembled and measured, it may be defined as an area based on the diameter at a position of 90% of the height of each columnar spacer 20.

  9 to 17 are sectional views showing a process for manufacturing the configuration of the embodiment 1 shown in FIG. 9 and 10 show processes on the TFT substrate 100 side. In the present invention, the substrate 100 is formed of a flexible resin. Among the resins, polyimide is particularly excellent as a substrate of a display device because of its mechanical strength and heat resistance, so the following explanation will be made on the premise of polyimide, but the present invention is used when other resins are used. Can also be applied.

  FIG. 9 shows a state where a polyimide substrate, which is a polyimide precursor to be the TFT substrate 100, is applied onto a glass substrate 400 and baked to form a polyimide substrate. Polyamide is formed by baking the polyamic acid at about 300 ° C. to 400 ° C. In order to form a flexible display device, the thickness of polyimide is, for example, 10 μm to 50 μm, and more preferably 10 μm to 20 μm. Since the manufacturing process cannot be performed only with such a thin substrate, the glass substrate 400 is obtained after the display device is completed through the manufacturing process while the polyimide substrate to be the TFT substrate 100 is placed on the glass substrate 400. Peel off.

  FIG. 10 is a sectional view showing a state in which the array layer 101 is formed on the polyimide substrate 100 formed as shown in FIG. In the case of an FFS (Fringe-Field-Swihching) panel, the array layer 101 is a base film made of SiO, SiN or the like, a switching element composed of a TFT including a semiconductor layer, an interlayer insulating film, a scanning line, a video signal line, and the like. A passivation film for protecting the layer, a common electrode, a pixel electrode, and the like are included. In the array layer 101, for example, the pixel electrode is formed closest to the liquid crystal layer.

    11 to 14 show a manufacturing process on the counter substrate 200 side. FIG. 11 is a cross-sectional view showing a state where up to the overcoat film 202 is formed on the counter substrate 200. In the present invention, the counter substrate 200 is also formed of polyimide, like the TFT substrate 100. The method for forming the counter substrate 200 using polyimide is the same as described with reference to FIG. Also on the counter substrate 200 side, the thickness of polyimide is 10 μm to 50 μm, more preferably 10 μm to 20 μm. In addition, passing through the manufacturing process with the glass substrate 500 attached is the same as the TFT substrate 100.

  In FIG. 11, a color filter layer 201 having a black matrix and a color filter is formed on a counter substrate 200 that has been baked and solidified, and an overcoat film 202 is formed on the color filter layer 201. The role of the overcoat film 202 is to prevent the pigment in the color filter layer 201 from contaminating the liquid crystal layer 300 and to flatten the surface.

  FIG. 12 shows a state where the columnar spacer 20 and the photosensitive resin 25 to be the outer wall 21 are applied on the overcoat film 202 and prebaked. As materials for the columnar spacers 20 and the outer wall 21 in the first embodiment, thermoplastic, thermosetting, and ultraviolet curable resins are used. These materials are bonded when heated under predetermined conditions or irradiated with ultraviolet rays. It is a material that expresses sex. Such materials are described in, for example, Patent Document 2, Patent Document 3, and the like. Thereafter, the columnar spacer 20 and the outer wall 21 are formed by photolithography. Since the columnar spacer 20 and the outer wall 21 are formed by photolithography, accurate dimensions can be ensured.

  FIG. 13 is a cross-sectional view showing a state in which the photosensitive resin 25 is patterned by photolithography. Since it is a photosensitive resin, it is not necessary to form a photoresist. The feature of FIG. 13 is that not only the columnar spacer 20 but also the outer wall 21 for sealing the liquid crystal 300 is formed simultaneously with the columnar spacer 20. Therefore, unlike the conventional sealing material 150 formed with a dispenser, fine processing is possible and the dimensions can be accurately controlled. The outer wall 21 in FIG. 13 is, for example, 10 μm, but may be about 100 μm in consideration of strength. After the columnar spacer 20 and the outer wall 21 are processed in this way, they are baked and fully cured.

FIG. 14 is a cross-sectional view showing a state in which the liquid crystal 300 is dropped by ODF (One Drop Fill) into the counter substrate 200 thus formed. In this embodiment, liquid crystal filling is performed with ODF, and thus no opening is formed in the outer wall 21 for injecting liquid crystal later.
In this embodiment, since the alignment film is not formed, a material for aligning the liquid crystal without the alignment film is added as the liquid crystal material.

  FIG. 15 is a cross-sectional view showing a state where the TFT substrate 100 side and the counter substrate 200 side formed in this manner are bonded together. In this state, the glass substrate 400 exists on the TFT substrate 100 side, and the glass substrate 500 exists on the counter substrate 200 side. In FIG. 15, after the TFT substrate 100 side and the counter substrate 200 side are bonded together, ultraviolet rays are irradiated or heated to cause the columnar spacer 20 and the outer wall 21 to exhibit adhesiveness, and are bonded to the TFT substrate 200 side. As a result, the liquid crystal 300 is sealed between the TFT substrate 100 and the counter substrate 200.

  Then, for example, by irradiating the sealed liquid crystal with polarized ultraviolet rays, an alignment layer for aligning the liquid crystal is formed at the interface between the TFT substrate and the liquid crystal or at the interface between the counter substrate and the liquid crystal. Orient.

  FIG. 16 shows the laser LB irradiated to the interface between the glass substrate and the polyimide substrate in order to peel the glass substrates 400 and 500 between the glass substrate 400 and the TFT substrate 100 and between the glass substrate 500 and the counter substrate 200. FIG. The glass substrate and the polyimide substrate are peeled off by so-called laser ablation. In order to perform peeling more efficiently, a metal layer or the like may be formed at the boundary between the glass substrate 400, 500 and the polyimide substrate 100, 200.

  FIG. 17 is a cross-sectional view showing a state in which the glass substrate 400 is peeled from the TFT substrate 100 and the glass substrate 500 is peeled from the counter substrate 200 by laser ablation. 17, the state where the glass substrates 400 and 500 are removed is the same as in FIG.

FIG. 18 is a cross-sectional view showing the configuration of the second embodiment. The plan view of the liquid crystal display device of Example 2 is the same as FIG. 5 differs from FIG. 5 in that an alignment film 103 is formed on the array layer 101 and an alignment film 203 is formed on the overcoat film 202.
In FIG. 18, an array layer 101 is formed on a TFT substrate 100 made of polyimide. The configuration of the array layer 101 is the same as described with reference to FIG. Further, a color filter layer 201 having a black matrix and a color filter is formed on the counter substrate 200 made of polyimide, and an overcoat film 202 is formed thereon.
On the overcoat film 202, the columnar spacers 30 and the outer wall 31 similar to those in the first embodiment are formed, and the material constituting the columnar spacers 30 and the outer wall 31 is formed of a material that exhibits adhesiveness by heating or ultraviolet irradiation. Has been. The columnar spacer 30 and the outer wall 31 can be formed by photolithography.

  Thereafter, an alignment film 203 is formed on the overcoat film 202 by, for example, inkjet. Although the alignment film 203 is also formed on the columnar spacer 30, it is omitted in FIG. 18 because it is hardly formed on the columnar spacer 30 by leveling. If a material that repels the alignment film material is used for the columnar spacer 30 and the outer wall 31, the alignment film can be excluded from the columnar spacer 30 and the like. Furthermore, if the alignment film 203 is patterned by photolithography, the alignment film can be reliably removed from the top of the columnar spacer 30. A liquid crystal 300 is sandwiched between the alignment film 103 on the TFT substrate side and the alignment film 203 on the counter substrate side. In this embodiment, the liquid crystal 300 is initially aligned by the alignment films 103 and 203.

  Also in FIG. 18, the adhesion between the TFT substrate 100 and the counter substrate 200 is maintained by bonding the columnar spacers 30 and the outer wall 31 formed on the counter substrate 200 side to the TFT substrate 100 side. In FIG. 18, the columnar spacers 30 are all in contact with the TFT substrate 100 side, which is the same as in the first embodiment. Also in this embodiment, since the TFT substrate 100 and the counter substrate 200 are made of polyimide, even if the repulsive force of the columnar spacer 30 is large, the TFT substrate 100 and the counter substrate 200 are less likely to be deformed flexibly and generate bubbles.

  FIG. 19 is an arrangement example of the columnar spacers 30 in the display area 40 in the second embodiment. The arrangement positions of the columnar spacers 30 in FIG. 19 and that all the columnar spacers 30 have the same diameter are the same as those in FIG. Also in FIG. 19, the columnar spacer 30 itself is exposed to heat or ultraviolet irradiation, and develops adhesiveness when it is cured or softened, and the alignment film 103 formed on the opposing substrate (in this case, the TFT substrate 100) Glue. Therefore, the adhesive layer 102 is unnecessary on the TFT substrate 100 side, and the alignment film 103 can be used.

  Also in the present embodiment, in order to use the columnar spacer 30 for bonding the TFT substrate 100 and the counter substrate 200, it is necessary to secure a contact ratio with respect to the display area of the columnar spacer 30 as in the first embodiment. It is. That is, the contact ratio needs to exceed 1%, more preferably 2% or more, and further preferably 4% or more. Also in the present embodiment, the outer wall 31 contributes to the adhesion between the TFT substrate 100 and the counter substrate 200 as in the first embodiment, and the contact ratio of the columnar spacer 30 is determined in consideration of the width of the outer wall 31. .

  20 is a cross-sectional view taken along line EE in FIG. The configuration on the TFT substrate 100 side and the configuration on the counter substrate 200 side in FIG. 20 are as described in FIG. In FIG. 20, the liquid crystal 300 is sandwiched between the alignment film 103 and the alignment film 203. In FIG. 20, since the alignment films 103 and 203 are formed on the TFT substrate 100 side and the counter substrate 200 side, normal liquid crystal can be used.

  21 to 26 are cross-sectional views showing a process for realizing the configuration of the present embodiment shown in FIG. FIG. 21 is a cross-sectional view showing a configuration on the TFT substrate 100 side. The manufacturing method on the TFT substrate 100 side is the same as that of the first embodiment except that the alignment film 103 is formed. That is, the polyimide substrate 100 is formed on the glass substrate 400, the array layer 101 is formed thereon, and the alignment film 103 is formed thereon.

  FIG. 22 is a cross-sectional view of the counter substrate 200 in a state where a photosensitive resin 35 for columnar spacers is applied and solidified. In FIG. 22, the process is the same as that described in Example 1 until the overcoat film 202 is formed. Thereafter, a photosensitive material 35 that is a precursor of the columnar spacer 30 or the outer wall 31 is applied on the overcoat film 202, and prebaked to be solidified.

  As the material for the columnar spacer 30 and the outer wall 31, thermoplastic, thermosetting, and ultraviolet curable resins are used. These materials exhibit adhesiveness when heated under predetermined conditions or irradiated with ultraviolet rays. Material.

  Thereafter, the columnar spacer 30 and the outer wall 31 are formed by photolithography. Since the columnar spacer 30 and the outer wall 31 are formed by photolithography, accurate dimensions can be ensured.

  After the photosensitive material 35 is solidified, an alignment film 203 is applied as shown in FIG. The alignment film 203 is applied to the entire surface, but the alignment film 203 is omitted because the columnar spacer 30 is hardly formed by leveling. In addition, if the material which repels alignment film material is used for the material of the columnar spacer 30 or the outer wall 31, an alignment film can be reliably excluded from the columnar spacer 30 grade | etc.,. Further, if the alignment film 203 is patterned by photolithography, the alignment film 203 can be removed from the columnar spacer. Thereafter, the alignment film 203 is baked. Then, an alignment process is performed on the alignment film 203. The alignment treatment may be a rubbing method or a photo-alignment method using polarized ultraviolet rays. Thereafter, as shown in FIG. 24, the liquid crystal 300 is dropped onto the counter substrate 200 by ODF, and the counter substrate 200 is filled with the liquid crystal 300. At this time, the columnar spacer 30 and the outer wall 31 are still in a semi-cured state, and adhesiveness is not expressed.

  Thereafter, as shown in FIG. 25, the TFT substrate 100 and the counter substrate 200 are bonded together, and the liquid crystal 300 is sealed inside the outer wall 31. When bonding the TFT substrate 100 side and the counter substrate 200 side, the columnar spacer 30 and the outer wall 31 are heated or irradiated with ultraviolet rays to develop adhesiveness, and the columnar spacer 30 and the outer wall 31 are attached to the TFT substrate 100 side. The alignment film 103 is adhered. After the columnar spacer 30 and the outer wall 31 are completely cured after heating or ultraviolet irradiation, the adhesion of the surfaces of the columnar spacer 30 and the outer wall 31 is lost. Therefore, the liquid crystal layer 300 is not contaminated.

  When the columnar spacer 30 and the outer wall are cured by ultraviolet rays or heat, the volume of the columnar spacer may shrink or slightly soften, and the height of the columnar spacer may be lowered. For this, the height of the columnar spacer after patterning may be set higher by, for example, about 0.2 μm to 0.5 μm than the height of the columnar spacer before the main curing.

  Thereafter, a laser beam is irradiated to the interface between the glass substrate 400 and the TFT substrate 100 and the interface between the glass substrate 500 and the counter substrate 200, and the glass substrate 400 and the glass substrate 500 are removed by laser ablation as shown in FIG. A flexible liquid crystal display device shown in FIG. 18 can be formed.

  As still another configuration of this embodiment, the alignment film on the TFT substrate side is made of a thermoplastic material, and a photo-exothermic material is included in a columnar spacer formed on the counter substrate side. After the TFT substrate and the counter electrode are bonded together, the columnar spacer is heated by irradiating light, the alignment film on the TFT substrate side is heated, and the adhesion is exhibited in the alignment film, and the columnar spacer and the alignment film are bonded. It can be set as the structure to do.

  As described above, according to the present embodiment, it is possible to realize a flexible liquid crystal display device that can narrow the frame width to an extent that it can hardly be recognized and widen the display area.

  FIG. 27 is a cross-sectional view of the liquid crystal display device showing the features of this embodiment. FIG. 27 corresponds to the CC cross-sectional view of FIG. FIG. 27 is different from FIG. 18 of the second embodiment in that the columnar spacer 30 is formed on the alignment film 203 on the counter substrate 200 side. On the other hand, in FIG. 18 of Example 2, the columnar spacer 30 is formed on the overcoat film 202, and after forming the columnar spacer 30, the alignment film 203 is formed. FIG. 28 showing the present embodiment is an enlarged cross-sectional view of the display area of FIG. FIG. 28 differs from FIG. 20 of the second embodiment in that the columnar spacer 30 is formed on the alignment film 203. Other configurations are the same as those in FIG.

  In the case of FIG. 18 or FIG. 20 of the second embodiment, it is considered that the alignment film 203 hardly remains on the columnar spacer 30 due to the leveling effect, but even the thin film remains on the upper surface of the columnar spacer 30. In this case, the adhesive force between the columnar spacer 30 and the alignment film 103 on the TFT substrate 100 side is affected.

  In this embodiment, since the columnar spacer 30 is formed after the alignment film 203 is formed, the alignment film 203 does not hinder the adhesion between the columnar spacer 30 and the alignment film 103 on the TFT substrate 100 side. However, in this case, the surface of the alignment film 203 may be affected by these processes in order to perform application of the photosensitive resin 35 for the columnar spacers 30, provisional baking, photolithography, and the like after the formation of the alignment film 203. There is sex. From such a viewpoint, it is necessary to examine the timing of the alignment treatment of the alignment film.

  The alignment treatment of the alignment film 203 can be performed immediately before the columnar spacers 30 are formed or after the columnar spacers 30 are formed. The method for forming the columnar spacers 30 and the outer wall 31 in this embodiment is the same as that in the second embodiment. The manufacturing process of the liquid crystal display device shown in FIG. 27 is the same as that described in the second embodiment except that the order of forming the alignment film 203 and the columnar spacer 30 is different.

In this embodiment, after the TFT substrate 100 and the counter substrate 200 are bonded together, the columnar spacer 30 and the outer wall 31 are formed by heating or irradiating the adhesive columnar spacer 30 and the outer wall 31 with each other. The alignment film 103 and the alignment film 203 are firmly bonded. In this case, the columnar spacer 30 or the outer wall 31 itself may exhibit adhesiveness at the time of the main curing, or the alignment film 103 or the alignment film 203 is made of a thermoplastic resin, and the columnar spacer 30 and the alignment films 103 and 203 are formed. May be bonded together.
(Supplementary explanation)
Here, various effects when the present invention is applied will be described. FIG. 29 is a plan view showing an end portion of a conventional liquid crystal display panel in which the sealing material 150 is formed by a dispenser. When applying the sealing material 150 with a dispenser, there is a limit to reducing the width of the sealing material 150 in order to prevent the sealing material 150 from being interrupted. Further, as shown in FIG. 29, the sealing material 150 applied to the counter substrate 200 with a dispenser is crushed when the counter substrate 200 and the TFT substrate 100 are bonded, and the shape becomes irregular. Therefore, it is necessary to set a large margin m1 between the sealing material 150 and the display region 40 in consideration of this irregularity.

  On the other hand, according to the present invention, as shown in FIG. 30, since the outer walls 21 and 31 can be formed by photolithography, fine processing with a width of about 10 μm is possible. Further, since the shape can be accurately controlled, a relatively small margin m2 is sufficient between the display area 40 and the display area 40. Therefore, the display area 40 can be set large from this point.

  FIG. 31 and FIG. 32 are comparative examples in the case where the display device is curved and used. FIG. 31 is a cross-sectional view showing a problem when the liquid crystal display device according to the conventional example is used while being curved. When the display device is used while being bent, a large bending stress is applied near the center of the screen. Therefore, the distance between the TFT substrate 100 and the counter substrate 200 is reduced near the center of the screen. Then, a change occurs in the chromaticity or luminance at the screen center and the screen periphery.

  FIG. 32 is a cross-sectional view when the liquid crystal display device of the present invention is used in a curved shape. In FIG. 32, the distance between the TFT substrate 100 and the counter electrode 200 is almost the same as the value d2 at the center of the screen and the value d1 at the periphery of the screen. In the present invention, since the columnar spacers 20 and 30 also serve to bond the TFT substrate 100 and the counter substrate 200, the contact ratio of the columnar spacers 20 and 30 to the display area exceeds 1% of the display area, preferably Is 2% or more, more preferably 4% or more. Therefore, the repulsive force due to the columnar spacers 20 and 30 is large, and the fluctuation of the distance between the TFT substrate 100 and the counter substrate 200 hardly occurs.

  In addition, in the present invention, not a glass substrate but a polyimide of 10 μm to 20 μm, for example, is used as the substrate, so that the bending stress itself is very small compared to the case of a glass substrate. Also from this point, the variation in the distance between the TFT substrate 100 and the counter substrate 200 when the display device is used in a curved shape can be suppressed to be small.

  Conventionally, the external shape of the liquid crystal display device is almost rectangular. However, in recent years, a liquid crystal display device having a shape other than a rectangle has been demanded. FIG. 33 shows an example in which a notch 41 is formed on a rectangular side. FIG. 34 is an example in which a circular hole 42 is formed in the display area 40. In FIGS. 33 and 34, it is necessary to form a seal for sealing the liquid crystal along the end of the notch 41 or the hole 42 in the portion where the notch 41 or the hole 42 is formed. If the outer wall for sealing the liquid crystal is formed by photolithography as in the present invention, it is possible to easily cope with such a seal shape and to realize a narrow frame display even in such a deformed portion. I can do it.

  FIG. 35 and FIG. 36 are examples when the external shape of the display device is not rectangular. FIG. 35 shows an example in which two opposing vertical sides protrude inward. FIG. 36 shows an example in which two opposing horizontal sides are curved in the same direction. In both cases, there are locations where adjacent sides intersect at an acute angle. Although it is difficult to apply the sealing material with a dispenser in such a portion, it is not particularly difficult to form the outer wall by photolithography as in the present invention.

  As described above, according to the present invention, a display device having a curved screen, a display device having an irregular outer shape, or a display region in which various irregular cutouts exist in the screen. It can be easily handled.

  DESCRIPTION OF SYMBOLS 10 ... Main columnar spacer, 11 ... Sub columnar spacer, 20, 30 ... Columnar spacer, 21, 31 ... Outer wall, 25, 35 ... Photosensitive resin for columnar spacers, 40 ... Display region, 50 ... Terminal region, 91 ... Scanning line 92 ... Video signal line 93 ... Pixel 100 ... TFT substrate 101 ... Array layer 103 ... Alignment film 200 ... Counter substrate 201 ... Color filter layer 202 ... Overcoat film 203 ... Alignment film

Claims (20)

A liquid crystal display device in which liquid crystal is sandwiched between a first substrate and a second substrate,
The first substrate and the second substrate are formed of a flexible substrate,
A plurality of columnar spacers are formed in a display region between the first substrate and the second substrate, and an outer wall is formed at a substrate end between the first substrate and the second substrate,
The columnar spacer and the outer wall are formed of a material that exhibits adhesiveness by ultraviolet irradiation or heating,
The liquid crystal display device, wherein the columnar spacer and the outer wall are bonded to both surfaces of the first substrate and the second substrate.   The liquid crystal display device according to claim 1, wherein the first substrate and the second substrate are made of polyimide.   2. The liquid crystal display device according to claim 1, wherein the first substrate and the second substrate are made of polyimide, and the thickness of the polyimide is 10 μm to 20 μm.   The contact ratio is 1% or more when a ratio of an area of the display region and an adhesion area where the columnar spacer is in contact with the first and second substrates is defined as a contact ratio. Item 2. A liquid crystal display device according to item 1.   The liquid crystal display device according to claim 4, wherein the contact ratio is 2% or more.   The liquid crystal display device according to claim 1, wherein an adhesive layer and an alignment film are not formed on the first substrate.   The liquid crystal display device according to claim 1, wherein the columnar spacer is bonded to a first alignment film formed on the first substrate.   The color filter layer is formed on the second substrate, an overcoat film is formed to cover the color filter, and the columnar spacer is formed on the overcoat film. Liquid crystal display device.   A color filter layer is formed on the second substrate, an overcoat film is formed to cover the color filter, a second alignment film is formed to cover the overcoat film, and the columnar spacer is the second spacer. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is formed on an alignment film.   A scanning line and a video signal line are formed on the first substrate, and the columnar spacer is located on the first substrate at a portion where the scanning line and the video signal line intersect when viewed in plan. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is in contact with the liquid crystal display device. A method of manufacturing a liquid crystal display device in which a liquid crystal is sandwiched between a first substrate and a second substrate,
Forming a first substrate and a second substrate with a flexible substrate;
Forming a photosensitive resin on the second substrate, and simultaneously forming a columnar spacer in a display region of the second substrate and an outer wall in a peripheral portion of the second substrate by photolithography;
Manufacturing of a liquid crystal display device characterized in that, when the first substrate and the second substrate are bonded, the columnar spacer and the outer wall are made to exhibit adhesiveness by heating or irradiating ultraviolet rays. Method.   12. The method of manufacturing a liquid crystal display device according to claim 11, wherein an adhesive layer is not formed on the first substrate.   When the ratio of the area of the display region and the adhesion area where the columnar spacer is in contact with the first and second substrates is defined as the contact ratio, the columnar spacer is arranged so that the contact ratio is 1% or more. The method of manufacturing a liquid crystal display device according to claim 11.   The method for manufacturing a liquid crystal display device according to claim 13, wherein columnar spacers are arranged so that the contact ratio is 2% or more. A method of manufacturing a liquid crystal display device in which a liquid crystal is sandwiched between a first substrate and a second substrate,
Forming a first substrate and a second substrate with a flexible substrate;
Forming a photosensitive resin on the second substrate, and simultaneously forming a columnar spacer in a display region of the second substrate and an outer wall in a peripheral portion of the second substrate by photolithography;
Forming a first alignment film on the first substrate;
When the first substrate and the second substrate are bonded, the columnar spacer and the outer wall are bonded to the first alignment film by heating or irradiating the columnar spacer and the outer wall with ultraviolet rays. A manufacturing method of a liquid crystal display device characterized by comprising:   The method of manufacturing a liquid crystal display device according to claim 15, wherein the alignment film is made of a thermoplastic resin.   A color filter layer is formed on the second substrate, an overcoat film is formed on the color filter layer, the columnar spacers and the outer wall are formed on the overcoat film, and then the second substrate is formed. The method of manufacturing a liquid crystal display device according to claim 15, wherein an alignment film is formed.   A color filter layer is formed on the second substrate, an overcoat film is formed on the color filter layer, a second alignment film is formed on the overcoat film, and the second alignment The method of manufacturing a liquid crystal display device according to claim 15, wherein the columnar spacer and the outer wall are formed on a film.   When the ratio of the area of the display region and the adhesion area where the columnar spacer is in contact with the first and second substrates is defined as the contact ratio, the columnar spacer is arranged so that the contact ratio is 1% or more. The method of manufacturing a liquid crystal display device according to claim 15.   The method for manufacturing a liquid crystal display device according to claim 19, wherein columnar spacers are arranged so that the contact ratio is 2% or more.

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