JP3653008B2 - Manufacturing method of liquid crystal display panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a liquid crystal display panel, and more particularly to a method for manufacturing a liquid crystal display panel in which spacers are arranged in a display region by a liquid crystal dropping method.
[0002]
[Prior art]
In general, a liquid crystal display panel has a structure in which two transparent substrates facing each other are bonded by a frame-shaped seal formed around a display area, and liquid crystal is sealed in a gap between both substrates surrounded by the seal. . In order to maintain the cell gap at an appropriate value, a spacer mixed in the seal (referred to as a seal spacer) or a spacer disposed in the display area (referred to as a display portion spacer) is used.
[0003]
As a method of manufacturing this liquid crystal display panel, there are a liquid crystal injection method and a liquid crystal dropping method from the viewpoint of a method of encapsulating liquid crystal. In any method, after the patterning process in which the insulating film and the transparent electrode film, the switch element, the color filter layer, and the like required according to the liquid crystal display method are formed on the transparent substrate, the liquid crystal molecules can be aligned. A rubbing step is performed in which an alignment film (such as a polyimide film) is printed and a groove for aligning is formed. Both methods will be different in subsequent assembly. Divide into the following
In the liquid crystal injection method, a liquid crystal display panel is assembled as follows. That is, a seal is formed in an open curve shape around the display area on one of the transparent substrates by drawing printing or screen printing using a dispenser. In addition, spacers are arranged or formed on one of the display areas on the transparent substrate. Thereafter, the two substrates are overlapped, the two substrates are pressed from the outside to adjust the gap between the two substrates to a desired value, and then the seal is cured. At this time, it is necessary to secure a desired cell gap. Thereafter, the liquid crystal is injected between both the substrates by a vacuum method using the opening of the seal as the liquid crystal injection port. Thereafter, the inlet is sealed with a sealing resin. Here, the vacuum method means that after a liquid crystal display panel having an opening for liquid crystal is installed in a vacuum apparatus and evacuated to a vacuum, the liquid crystal inlet is immersed in a liquid crystal tank filled with liquid crystal, and the atmospheric pressure is gradually increased. In this method, the liquid crystal is injected into the liquid crystal display panel by increasing the number.
[0004]
On the other hand, in the liquid crystal dropping method, a liquid crystal display panel is assembled as follows. That is, a seal is formed in a closed curve around the display area on one of the transparent substrates by drawing printing or screen printing using a dispenser. In addition, spacers are arranged or formed on at least the display area on the transparent substrate by forming or scattering. Thereafter, an appropriate amount of liquid crystal is dropped onto a transparent substrate on which a seal is attached and the display unit spacer is arranged. Thereafter, both substrates are positioned and bonded together in a vacuum chamber. Next, it is left under atmospheric pressure and deformed so that the panel is pinched due to the differential pressure between the atmospheric pressure and the negative pressure in the liquid crystal display panel, and the gap between the substrates is narrowed. When the desired cell gap is obtained by this deformation, the seal is cured.
[0005]
In either method, thermosetting resin or ultraviolet curable resin is mainly used for the seal. Moreover, spherical spacers or cylindrical granular spacers are used as seal spacers or display spacers to be dispersed. The display portion spacer arranged by formation refers to a columnar spacer or the like formed by patterning.
In either method, the two substrates are finally cut to form an outer shape of the liquid crystal display panel, and polarizing plates are attached to the front and rear surfaces of the panel to complete the liquid crystal display panel.
[0006]
[Problems to be solved by the invention]
In the conventional liquid crystal display panel manufacturing method using the conventional liquid crystal dropping method, the following inconvenience occurs between the time when the panel on which both substrates are bonded is released under atmospheric pressure and the seal is cured. It was.
[0007]
In the following, problems in the method of manufacturing a liquid crystal display panel by a conventional liquid crystal dropping method will be described by taking a TFT drive type color LCD panel as an example.
[0008]
2A to 2C are schematic cross-sectional views of a liquid crystal display panel 20 according to a conventional manufacturing method. The liquid crystal display panel 20 is an example of a TFT drive type color LCD panel. As shown in FIG. 2, the liquid crystal display panel 20 is mainly sandwiched between the TFT substrate 1, the color filter substrate 2 provided with the RGB coloring layer 22 facing the TFT substrate 1, and the substrates 1 and 2. Liquid crystal 3, a seal 4 that bonds the substrates 1 and 2 together and seals the liquid crystal 3, a seal spacer 5 that is mixed in the seal 4, and a display unit spacer 16 that is arranged in the display area. The The initial average dimension in the cell gap direction of the display unit spacer 16 is set to a value equal to the appropriate cell gap value d0 to be formed in order to properly perform liquid crystal display. The dimension in the cell gap direction corresponds to the diameter if the spacer is a spherical or cylindrical granular spacer, and the height if the spacer is a columnar spacer.
[0009]
FIG. 2A shows a state immediately after the liquid crystal 3 is dropped on the TFT substrate 1 on which the seal 4 is formed and the display unit spacer 16 is arranged, the substrates 1 and 2 are bonded together in the vacuum chamber, and taken out into the atmosphere. Is shown. In this state, the inside of the liquid crystal display panel 20 is in a pressure state (negative pressure) lower than atmospheric pressure, and the liquid crystal 3 has not yet filled the entire area of the liquid display panel 20, and the vacuum part 7 exists. Thereafter, the liquid crystal display panel 20 is deformed so that the distance between the TFT substrate 1 and the color filter substrate 2 is narrowed due to the pressure difference between the atmospheric pressure and the negative pressure in the panel. In FIG. 2, the color filter substrate 2 is deformed or fluctuated because the TFT substrate 1 is placed on the horizontal surface. Due to this deformation and fluctuation, the liquid crystal 3 is crushed and gradually spreads in the surface direction within the panel, and the vacuum portion 7 decreases.
[0010]
However, the deformation of the liquid crystal display panel 20 proceeds faster at the central portion than at the outer peripheral portion, as shown in FIG. This is because the viscosity of the liquid crystal 3 is extremely lower than the viscosity of the seal 4 while the atmospheric pressure is equally applied to the substrate. That is, the drag force exerted on the color filter substrate 2 by the liquid crystal 3 is smaller than the drag force exerted on the color filter substrate 2 by the seal 4. The viscosity of the liquid crystal 3 is about 0.02 (Pa · s), and the viscosity of the adhesive resin used for the seal 4 is about several tens to several hundreds (Pa · s).
[0011]
Since the deformation of the liquid crystal display panel 20 proceeds faster in the central portion than in the outer peripheral portion, the inner surface of the color filter substrate 2 reaches the display portion spacer 16 disposed in the central portion earliest. When the color filter substrate 2 is further pressed after this arrival and the color filter substrate 2 is in pressure contact with the display unit spacer 16, the color filter substrate 2 receives the drag of the display unit spacer 16, and the progress of the deformation is suppressed. FIG. 2B shows the state at this time. In the state shown in FIG. 2B, the display unit spacer 16 disposed in the center is compressed and deformed, and the cell gap in the center is smaller than the appropriate cell gap d0. This is because the initial dimension in the cell gap direction of the display portion spacer 16 before compression is set to a value equal to the appropriate cell gap value d0.
Further, in the state shown in FIG. 2B, the vacuum part 7 still exists and the pressure inside and outside the panel is not balanced (the internal pressure is not equal to the atmospheric pressure). . The deformation proceeds exclusively at the outer periphery. This is because, in the central portion, both the substrates 1 and 2 are subjected to the drag of the display portion spacer 16 and the progress of deformation and variation is suppressed.
[0012]
Thereafter, the deformation of the outer peripheral portion proceeds, and the state as shown in FIG. In the state shown in FIG. 2C, the deformation of the outer peripheral portion proceeds, and finally the vacuum portion 7 in the panel 20 disappears, the volume in the panel 20 becomes equal to the volume of the liquid crystal 3, and the pressure inside and outside the panel is balanced. It is in the state.
[0013]
In the state shown in FIG. 2C, the inner surface of the color filter substrate 2 is not in contact with the seal spacer 5. That is, the seal spacer 5 is not sandwiched between the two substrates 1 and 2 and sufficiently functions to maintain the gap between the substrates 1 and 2 at the seal portion and regulate it to an appropriate value (function as a spacer). Not.
[0014]
In addition, the inner surface of the color filter substrate 2 is not in contact with the display unit spacer 16 disposed on the outer periphery. That is, the display portion spacer 16 disposed on the outer peripheral portion is not sandwiched between the two substrates 1 and 2, and has a function of holding the gap between the two substrates 1 and 2 and regulating it to an appropriate value (function as a spacer). It has not been demonstrated, and the proper cell gap has not been reached at the outer periphery.
[0015]
Therefore, as shown in FIG. 2C, the cell gap value d1 at the center of the liquid crystal display panel 20 is smaller than the appropriate cell gap d0 (d1 <d0), and the cell gap value d3 at the outer peripheral portion is the appropriate cell gap. It is larger than d0 (d3> d0), and there is a portion in which an appropriate cell gap is obtained (d2 = d0).
[0016]
As described above, the pressure inside and outside the panel is balanced in a state where the cell gap is not uniform, and the progress of the deformation is stopped because the amount of the liquid crystal 3 becomes an appropriate cell gap value d0 over the entire cell gap. This is because the amount is set equal to the volume in the panel 20 in the state. That is, the capacity of the liquid crystal 3 corresponding to the cell gap being smaller than the appropriate cell gap value d0 at the center is pushed to the outer periphery, and the cell gap at the outer periphery is larger than the appropriate cell gap.
The state shown in FIG. 2C is a metastable state and lasts for a while. If the seal 4 is not cured for a considerable period of time, the panel 20 may be deformed in the direction of uniform cell gap by the drag of the display spacer 16 at the center, and a uniform cell gap may be obtained. However, since the pressure is directly applied to the seal 4 since the panel 20 was opened under the atmospheric pressure, if the seal 4 is left uncured under the atmospheric pressure for too long, the seal 4 is broken. There is a risk of being. The time from the release to the atmosphere to the curing of the seal is several minutes to several tens of minutes. Therefore, the seal 4 must be cured while maintaining a nonuniform cell gap in such a manner that the cell gap at the center is small and the cell gap at the outer periphery is large with respect to the appropriate cell gap value as shown in FIG. Must not.
[0017]
Here, the pressure acting on the seal 4 will be described with reference to FIG. FIG. 3 is a plan view of the TFT substrate after seal printing and liquid crystal dropping. As shown in FIG. 3, the auxiliary seal 8 may be formed in a closed curve shape so as to surround the seal 4. FIG. 3 shows a case where a region serving as two liquid crystal display panels is included in one auxiliary seal 8. The auxiliary seal 8 is used to form and maintain a vacuum space between the substrate 4 and the seal 4 to increase and maintain the pressure applied to the substrate by atmospheric pressure.
Since the pressure inside the seal 4 increases as the panel is deformed, the internal pressure is applied to the seal 4 on the inner peripheral surface.
[0018]
Further, when the auxiliary seal 8 is ruptured by atmospheric pressure, atmospheric pressure is applied to the outer peripheral surface of the seal 4. Naturally, in the manufacturing method not using the auxiliary seal 8, the atmospheric pressure is applied to the outer peripheral surface of the seal 4 from the time when the panel is opened to the atmospheric pressure.
[0019]
In the liquid crystal injection method, as described above, the panels are assembled by bonding the two substrates together and curing the seal, and then the liquid crystal is injected from the opening of the seal. Therefore, even when the cell gap becomes smaller than the proper cell gap at the time of panel assembly, since the seal has an opening, the proper cell gap can be recovered after the elasticity of the spacer and the liquid crystal injection process. On the other hand, in the liquid crystal dropping method, since the liquid crystal is sealed and the cell gap is formed in a sealed state, it is difficult to recover the appropriate cell gap once the non-uniform cell gap is formed.
[0020]
As described above, in the conventional method of manufacturing a liquid crystal display panel using the liquid crystal dropping method, a nonuniform cell having a mode in which the cell gap at the center is small and the cell gap at the outer periphery is large with respect to the appropriate cell gap value. A gap liquid crystal display panel is obtained. For this reason, since the display portion spacers arranged on the outer peripheral portion do not support the substrate, the display portion spacer easily deforms due to the influence of external pressure and weight, and the cell gap uniformity cannot be obtained. Furthermore, the liquid crystal expands and contracts due to temperature changes, and the amount of change in the cell gap differs between the central portion and the outer peripheral portion, and the change in display state differs between the central portion and the outer peripheral portion.
[0021]
As a result, there is a problem that the display quality of the liquid crystal display panel is deteriorated.
[0022]
The present invention has been made in view of the above-described problems in the prior art, and in a manufacturing method by a liquid crystal dropping method of a liquid crystal display panel in which a spacer is arranged in a display region, the panel is caused by a difference in viscosity between a seal and a liquid crystal. A method of manufacturing a liquid crystal display panel capable of manufacturing a liquid crystal display panel having an appropriate cell gap in the entire display region and maintaining a good display quality while avoiding inconvenience due to partial differences in the display area. With the goal.
[0023]
[Means for Solving the Problems]
According to the present invention, in a method of manufacturing a liquid crystal display panel by a so-called liquid crystal dropping method, a spacer having an initial dimension in the cell gap direction larger than an appropriate cell gap to be formed in order to properly perform liquid crystal display is used. It is characterized by that.
[0024]
More specifically, in manufacturing a liquid crystal display panel in which two opposing transparent substrates are bonded by a seal and liquid crystal is sealed in a gap between the substrates surrounded by the seal, the display region is surrounded on the transparent substrate. After the liquid crystal is dropped on the inner area of the seal on the transparent substrate, the substrates are bonded to each other through the seal in the vacuum chamber. In the method of manufacturing a liquid crystal display panel in which the seal is cured after the panel is deformed by atmospheric pressure, the panel is deformed by atmospheric pressure, and the volume in the panel is equal to the volume of the liquid crystal, the liquid crystal display is used as a spacer. A method of manufacturing a liquid crystal display panel, characterized in that a liquid crystal display panel having a larger initial dimension in the cell gap direction than a proper cell gap to be formed properly is used.
[0025]
Here, the initial dimension means a dimension in a free state that is not particularly subjected to a compressive load or the like, and means an average dimension of the spacer to be used when there is variation in the dimension of the spacer.
[0026]
Therefore, according to the method of manufacturing the liquid crystal display panel of the first invention, as the display unit spacer, the one having the initial dimension in the cell gap direction larger than the appropriate cell gap to be formed in order to properly perform the liquid crystal display is used. Compared with the case where a display unit spacer having an initial dimension in the cell gap direction equal to the appropriate cell gap is used, it is possible to prevent the cell gap from being excessively collapsed below the appropriate cell gap due to the atmospheric pressure applied to the liquid crystal display panel. it can. Therefore, when the volume in the panel is equal to the volume of the liquid crystal and the deformation of the panel becomes a metastable state, the cell gap in the center is small and the cell gap in the outer periphery is large with respect to the appropriate cell gap value. It is possible to prevent a liquid crystal display panel having a non-uniform cell gap from being generated, and to obtain a liquid crystal display panel having a uniform cell gap by alleviating the non-uniformity of the cell gap at the outer periphery of the central portion. is there.
[0027]
Of course, as has been done in the past, the amount of liquid crystal is set to an amount equal to the volume in the panel when the cell gap is the appropriate cell gap over the entire display area. There is an advantage that a liquid crystal display panel having a gap and good display quality can be obtained.
[0028]
In addition, since a display portion spacer having an initial dimension in the cell gap direction larger than an appropriate cell gap to be formed in order to properly perform liquid crystal display is used, the display portion spacer in the entire display region is sandwiched between both substrates. Thus, it fully functions as a spacer for regulating the cell gap to an appropriate value. As a result, there is an advantage that the uniformity of the cell gap is improved and maintained.
[0029]
The present invention requires that the seal is cured after the volume in the panel and the volume of the liquid crystal become equal, and as a result, it cannot be compressed and deformed to an appropriate cell gap depending on the atmospheric pressure applied to the panel. No spacer (for example, a spacer that is too large compared to the appropriate cell gap or a hard spacer that is slightly larger but hardly deformed) is not used as the display portion spacer. When such a spacer is used, a cavity is left in the panel, and the volume in the panel is not equal to the volume of the liquid crystal. That is, in the present invention, the conditions of the display spacer are set so that the display spacer can be compressed and deformed to an appropriate cell gap by the atmospheric pressure applied to the panel.
[0030]
The second invention is characterized in that, in the liquid crystal display panel manufacturing method of the first invention, a spacer that elastically deforms from an initial dimension to the appropriate cell gap is used as the spacer.
[0031]
Therefore, according to the method of manufacturing the liquid crystal display panel of the second invention, since the spacer that elastically deforms from the initial dimension to the appropriate cell gap is used as the display unit spacer, the deformation from the initial dimension to the appropriate cell gap is caused by atmospheric pressure. There is an advantage that it is easy to obtain.
[0032]
Further, in the liquid crystal display panel manufactured according to the present invention, the display portion spacer is sandwiched between both substrates in a state of being subjected to compressive deformation at room temperature, so that an appropriate cell gap is maintained over the entire display region for a long time. There are advantages. This is because the compressive stress (drag) of the display spacer acts on the entire panel, so that the entire panel is not easily deformed against an external force. In addition, if the display unit spacer is not sandwiched, the display unit spacer may move within the panel after the liquid crystal display panel is completed. As a result of the movement, the display unit spacer is unevenly distributed and the cell gap is uniformly maintained throughout the display region. This is because a phenomenon may occur in which the cell gap becomes non-uniform due to loss of the cell.
[0033]
A resin spacer may be used as the elastic deformation from the initial dimension to the appropriate cell gap.
[0034]
According to a third aspect of the present invention, in the method for manufacturing a liquid crystal display panel according to the first or second aspect, a spacer made of a material that does not substantially deform even when sandwiched between both substrates by the action of atmospheric pressure is used as a seal. It is characterized by using a mixed seal.
Therefore, according to the manufacturing method of the liquid crystal display panel of the third invention, since the spacer made of a material that hardly deforms even when sandwiched between both substrates by the action of atmospheric pressure is used as the seal spacer, There is an advantage that the gap between them can be accurately maintained.
[0035]
The dimension of the seal spacer in the cell gap direction is set to such an extent that the cell gap in the display region becomes an appropriate cell gap when the seal spacer is sandwiched between the two substrates. The relative value of the initial average dimension to the appropriate cell gap value is preferably in the range of more than 102.9% and less than 107.0%. In particular, the relative value is desirably 105% plus or minus 2%.
[0036]
Further, in order to give the seal spacer a material that hardly deforms even when sandwiched between both substrates by the action of atmospheric pressure, it is preferable to use a material having high hardness such as glass or silica.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
A method of manufacturing a liquid crystal display panel according to an embodiment of the present invention will be described below with reference to the drawings, taking a thin film transistor (TFT) driven color liquid crystal display (LCD) panel as an example. The following is one embodiment of the present invention and does not limit the present invention.
[0038]
FIG. 1 shows a schematic cross-sectional view of a liquid crystal display panel 10 according to the manufacturing method of the present invention. The liquid crystal display panel 10 is a TFT drive type color LCD panel. As shown in FIG. 1, a liquid crystal display panel 10 mainly includes a TFT substrate 1, a color filter substrate 2 facing the TFT substrate 1, a liquid crystal 3 sandwiched between the substrates 1 and 2, both substrates 1, 2 and a seal 4 for sealing the liquid crystal 3, a seal spacer 5 mixed in the seal 4, and a display portion spacer 6 arranged in the display area.
[0039]
The initial average dimension in the cell gap direction of the display unit spacer 6 is set to a value larger than the appropriate cell gap value d0 to be formed in order to properly perform liquid crystal display. The dimension in the cell gap direction corresponds to the diameter if the spacer is a spherical or cylindrical granular spacer, and the height if the spacer is a columnar spacer.
[0040]
Further, the conditions of the display unit spacer 6 are set so that the display unit spacer 6 can be compressed and deformed to an appropriate cell gap by the atmospheric pressure applied to the panel 10.
The conditions for this spacer are the properties of the spacer (spacer dimensions (height, cross-sectional area, etc.), mechanical properties (elasticity, plasticity, etc.)) and the number of spacers that exist per unit area on the transparent substrate (transparent The density depends on the density of spacers existing on the substrate), the viscosity of the seal, the viscosity of the liquid crystal, and the like.
[0041]
Further, in the present embodiment, a resin spacer is used for the display unit spacer 6 so as to be elastically deformed from the initial dimension to the appropriate cell gap value d0.
[0042]
In the present embodiment, a glass spacer is used for the seal spacer 5 as a material that hardly deforms even when sandwiched between the substrates 1 and 2 by the action of atmospheric pressure.
[0043]
FIG. 1A shows a state immediately after the liquid crystal 3 is dropped on the TFT substrate 1 on which the seal 4 is formed and the display unit spacer 6 is arranged, the substrates 1 and 2 are bonded together in the vacuum chamber, and taken out into the atmosphere. Is shown. In this state, the inside of the liquid crystal display panel 10 is in a pressure state (negative pressure) lower than the atmospheric pressure, and the liquid crystal 3 has not yet filled the entire area of the liquid display panel 10 and the vacuum part 7 exists. Thereafter, the liquid crystal display panel 10 is deformed so that the distance between the TFT substrate 1 and the color filter substrate 2 is narrowed due to the pressure difference between the atmospheric pressure and the negative pressure in the panel. In FIG. 1, the color filter substrate 2 is deformed or fluctuates because the TFT substrate 1 is placed on a horizontal plane. Due to this deformation and fluctuation, the liquid crystal 3 is crushed and gradually spreads in the surface direction within the panel, and the vacuum portion 7 decreases.
[0044]
However, the deformation of the liquid crystal display panel 10 proceeds faster at the central portion than at the outer peripheral portion, as shown in FIG. This is because the viscosity of the liquid crystal 3 is extremely lower than the viscosity of the seal 4 while the atmospheric pressure is equally applied to the substrate. That is, the drag that the liquid crystal 3 exerts on the color filter substrate 2 is smaller than the drag that the seal 4 exerts on the color filter substrate 2. The viscosity of the liquid crystal 3 is about 0.02 (Pa · s), and the viscosity of the adhesive resin used for the seal 4 is about several tens to several hundreds (Pa · s).
[0045]
Since the deformation of the liquid crystal display panel 10 proceeds faster in the central portion than in the outer peripheral portion, the inner surface of the color filter substrate 2 reaches the display portion spacer 6 disposed in the central portion earliest. When the color filter substrate 2 is further pressed after this arrival and the color filter substrate 2 is in pressure contact with the display unit spacer 6, the color filter substrate 2 receives the drag of the display unit spacer 6, and the progress of the deformation is suppressed. FIG. 1B shows the state at this time. In the state shown in FIG. 1B, the display portion spacer 6 disposed in the center portion is compressed and deformed, and the cell gap in the center portion is substantially equal to the appropriate cell gap d0. This is because the initial average dimension in the cell gap direction of the display unit spacer 6 is set to a value larger than the appropriate cell gap value d0, and the display unit spacer 6 can be compressed and deformed to the appropriate cell gap by the atmospheric pressure applied to the panel 10. This is because the condition of the display unit spacer 6 is set to some extent. Even if the cell gap in the central portion may reach a value smaller than the appropriate cell gap d0, the minimum reached cell gap becomes smaller when a spacer having an initial dimension in the cell gap direction equal to the appropriate cell gap is used. The minimum cell gap can be stopped at a value closer to the appropriate cell gap d0.
[0046]
Further, in the state shown in FIG. 1B, the vacuum part 7 still exists and the pressure inside and outside the panel is not balanced, so that the deformation proceeds after this. The deformation proceeds exclusively at the outer periphery. This is because, in the central portion, both the substrates 1 and 2 are subjected to the drag of the display portion spacer 6 to suppress the progress of deformation and variation.
[0047]
Thereafter, the deformation of the outer peripheral portion proceeds, and a state as shown in FIG. 1C is obtained, and the progress of the deformation of the outer peripheral portion of the liquid crystal display panel 10 is suppressed by the seal spacer 5. The state shown in FIG. 1C is a state in which the outer peripheral portion has been deformed, and finally the inner surface of the color filter substrate 2 is in contact with the seal spacer 5. At this time, since the glass seal spacer 5 hardly deforms, the gap between the substrates 1 and 2 is kept constant with high accuracy.
[0048]
Further, in the state shown in FIG. 1C, the display portion spacer 6 disposed on the outer peripheral portion is sandwiched between the substrates 1 and 2 and is compressed and deformed to have an appropriate cell gap value d0. That is, the appropriate cell gap value d0 is almost reached at the outer peripheral portion.
[0049]
In addition, since the internal pressure is increased due to the collapse of the liquid crystal 3 existing in the outer peripheral portion, the cell in the central portion can be obtained even when the cell gap in the central portion reaches a value smaller than the appropriate cell gap d0 in FIG. The gap value is restored to the appropriate cell gap value d0.
[0050]
In the case of FIG. 1C, even if there is a portion having a cell gap slightly larger than the appropriate cell gap, the amount of the liquid crystal 3 is set to the appropriate cell gap value d0 over the entire display area. Since the volume is set equal to the volume in the panel 10 in the state, a fine vacuum part (not shown) still exists in the panel 10, and the pressure in the panel 10 is still equal to the atmospheric pressure. Absent. That is, since the pressure in the panel 10 is negative, the panel 10 is slowly deformed toward the appropriate cell gap value d0 in the entire display region until the volume in the panel 10 and the volume of the liquid crystal 3 become equal.
[0051]
As a result, the liquid crystal 3 spreads over the entire area of the panel 10 with a uniform thickness, the vacuum portion disappears, and the pressure inside and outside the panel is balanced, so that the liquid crystal display panel 10 having an appropriate cell gap value d0 over the entire display area is obtained. . According to such a liquid crystal display panel 10, good display quality can be ensured.
[0052]
Next, the seal 4 is cured. When an ultraviolet curable adhesive is used for the seal 4, the seal 4 can be cured by irradiating ultraviolet rays. When a thermosetting adhesive is used for the seal 4, the seal 4 can be cured by applying a temperature of about 120 ° C. for 1 hour or longer.
[0053]
Thereafter, the liquid crystal display panel is completed by cutting the outer shape of the panel and attaching polarizing plates to the front and rear surfaces.
[0054]
According to the present embodiment, when the pressure inside and outside the panel is balanced as in the conventional method using a spacer having an initial dimension in the cell gap direction equal to the appropriate cell gap, the seal spacer 5 has the color filter substrate 2 The inner surface is not in contact with each other, and the seal spacer 5 is sandwiched between the two substrates 1 and 2 and functions to maintain the gap between the substrates 1 and 2 at the seal portion to regulate to an appropriate value (function as a spacer). ) Fully.
[0055]
In addition, the inner surface of the color filter substrate 2 is in pressure contact with the display unit spacer 6 arranged on the outer peripheral portion, and the function of holding the gap between the substrates 1 and 2 to regulate to an appropriate value (function as a spacer). Demonstrating.
[0056]
[Experimental example]
Next, the display unit spacer 6 is compressed and deformed to an appropriate cell gap by the atmospheric pressure applied to the panel 10 to obtain a condition for the display unit spacer 6 to be set in order to obtain an appropriate cell gap in the entire display region. An experimental example by the inventor will be described.
[0057]
[Contents of experiment]
A spherical display portion spacer 6 having an initial average dimension φ of 6.0 μm was sprayed, and the appropriate cell gap value d0 was controlled by the dropping amount of the liquid crystal 3. The relative value (6.0 / d0) of the initial average dimension with respect to the appropriate cell gap value d0 was calculated. As a result, the state of the obtained liquid crystal display panel was inspected.
[0058]
[Experimental Conditions] Experimental conditions are disclosed below.
[0059]
(Condition 1) According to the above embodiment.
[0060]
(Condition 2) An auxiliary seal 8 as shown in FIG. 3 was used.
[0061]
(Condition 3) The shape of the display portion spacer 6 is spherical, the material is a polymer resin of divinylbenzene, the diameter is φ6.0 μm, and the spraying density is 200 to 250 / mm. ² It was.
[0062]
(Condition 4) An ultraviolet curable adhesive was used as the seal 4 and the auxiliary seal 8, and the viscosity thereof was about 300 (Pa · s).
[0063]
(Condition 5) The material of the seal spacer 5 is glass, the shape is spherical, and the size is φ6.5 μm.
[0064]
(Condition 6) The liquid crystal 3 has a viscosity of 0.018 to 0.02 (Pa · S).
[0065]
[Experimental Results and Verification] The experimental results and verification of the experimental results are disclosed below.
[0066]
(i) (d0, 6.0 / d0) = (5.99, 100.2%) The seal 4 is pressed from the inner side to the outer side of the panel 10, a part of the seal 4 is ruptured, and the liquid crystal 3 is sealed. Leaked into the area between 4 and the auxiliary seal 8. This is because the initial dimension of the display unit spacer 6 is smaller than d0. It is necessary to make the initial dimension of the display unit spacer 6 relatively larger.
[0067]
(ii) (d0, 6.0 / d0) = (5.83, 102.9%) Cracks were found on the outer peripheral surface of the seal 4. This was because the seal 4 was compressed from the inside to the outside of the panel 10. It is necessary to make the initial dimension of the display unit spacer 6 relatively larger.
[0068]
(iii) (d0, 6.0 / d0) = (5.72, 104.9%) No particular failure was found.
[0069]
(iv) (d0, 6.0 / d0) = (5.61, 107.0%) A variation was observed in the cell gap. This is because the initial dimension of the display unit spacer 6 is slightly larger than d0. It is necessary to make the initial dimension of the display unit spacer 6 smaller.
[0070]
(v) (d0, 6.0 / d0) = (5.50, 109.1%) A variation was observed in the cell gap. This is because the initial dimension of the display unit spacer 6 is slightly larger than d0. It is necessary to make the initial dimension of the display unit spacer 6 smaller.
[0071]
From the above results, the optimum value of the relative value of the initial average dimension with respect to the appropriate cell gap value is in the range of more than 102.9% and less than 107.0%, preferably about 105% plus or minus 2%. I was able to estimate. More preferably, it is about 105%. This tendency does not change much even if the viscosity of the seal is different.
[0072]
By the experiment as described above, the display spacer 6 is compressed and deformed to an appropriate cell gap by the atmospheric pressure applied to the panel 10, and the conditions of the display spacer 6 to be set in order to obtain an appropriate cell gap in the entire display region are determined. Can be sought.
[0073]
【The invention's effect】
As described above, the present invention uses a display spacer having an initial dimension in the cell gap direction larger than the appropriate cell gap to be formed in order to perform liquid crystal display properly. There is an effect that a liquid crystal display panel having an appropriate cell gap in the entire display region and having good display quality can be obtained.
[0074]
Further, in the liquid crystal display panel manufactured according to the present invention, the display spacer is sandwiched between both substrates in a state of being subjected to compressive deformation at room temperature, so the entire panel is deformed by the compressive stress (drag) of the display spacer. This makes it possible to maintain a proper cell gap over the entire display area for a long time.
[Brief description of the drawings]
FIG. 1 is a schematic process cross-sectional view illustrating a manufacturing method according to the present invention.
FIG. 2 is a schematic process cross-sectional view illustrating a conventional manufacturing method.
FIG. 3 is a schematic plan view showing a TFT substrate after multi-face printing and liquid crystal dropping.
[Explanation of symbols]
1 TFT substrate
2 Color filter substrate
3 LCD
4 Seal
5 Seal spacer
6, 16 Display spacer
7 Vacuum part
8 Auxiliary seal
10, 20 LCD panel
22 Colored layer

Claims (1)

In a method for manufacturing a liquid crystal display panel, a step of forming a seal member so as to surround a display region on at least one of two opposing transparent substrates, and a liquid crystal display appropriately on the display region on the substrate A step of disposing a first elastically deforming spacer having an initial dimension in the cell gap direction larger than an appropriate cell gap to be formed; and a step of dropping liquid crystal in a region on the substrate that is inside the seal member; After the step of dripping the liquid crystal, the two transparent substrates are bonded together in the vacuum chamber with the seal member interposed therebetween, and after the step of forming the panel, the panel is exposed to the atmosphere. The first spacer is deformed by opening the inside and deforming the panel by atmospheric pressure, and the volume in the panel is equal to the volume of the liquid crystal. And a step of curing the seal member, and as the seal member, a seal mixed with a second spacer made of a material that hardly deforms even when sandwiched between the substrates by the action of atmospheric pressure. A method of manufacturing a liquid crystal display panel, wherein a member is used and a relative value of an initial average dimension with respect to the appropriate cell gap value is in a range of more than 102.9% and less than 107.0% .

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