JP3925535B2 - Manufacturing method of liquid crystal display device - Google Patents

Description

  The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly to a method for manufacturing a liquid crystal cell configured by bonding two substrates together with a sealing material.

  Conventionally, there are various methods for manufacturing a liquid crystal display device, and the following methods are generally employed. First, wiring layers and pixel electrodes are formed on the inner surfaces of two glass substrates, and active elements, color filters, and the like are formed as necessary. Next, a sealing material is applied to either one of the two glass substrates so as to surround the liquid crystal display region while leaving one opening, and the other glass substrate is attached via the sealing material. .

  The two glass substrates are bonded to each other with a predetermined pressure by a press device, and then light and heat are applied to the two bonded glass substrates to cure the sealing material. A cell is formed. Liquid crystal is injected into the liquid crystal cell from the opening of the sealing material under reduced pressure, and after the injection is completed, the opening is sealed.

  The glass substrate pressure bonding process and the sealing material curing process are performed by various methods depending on the type of the liquid crystal cell. For example, when a large number of spacers are dispersedly arranged between glass substrates, the two glass substrates are pressurized and temporarily bonded, and transferred to another jig as it is or as a space between the glass substrates. A liquid crystal cell having an accurate cell gap can be formed by curing the sealing material while being held.

  Although no spacer is disposed between the glass substrates, a spacer having the same size as the desired cell gap is mixed in the sealing material, and pressure is applied to the portion where the sealing material exists to temporarily apply the spacer. In some cases, the sealing material is cured after the pressure bonding.

  In the above conventional method for manufacturing a liquid crystal display device, the plane position between the substrates cannot always be set accurately when the two glass substrates are bonded together. As a result, the assembly between the two glass substrates is not possible. Deviation occurs, and variations in display characteristics and deterioration due to deviation of the pixel structure formed on the inner surface of the glass substrate become a problem.

  Further, in the method of manufacturing the other glass substrate as a large size and manufacturing the one glass substrate as a small substrate corresponding to the liquid crystal display cell, when the pressure bonding and temporary curing are performed on a plurality of small substrates at once, the pressure bonding is performed. Since the degree of deformation of the glass substrate changes greatly depending on the pressure at the time and the degree of curing of the sealing material, the glass substrate after the liquid crystal cell is finished warps and dents to form a liquid crystal cell with a uniform cell gap There is also the problem that it is difficult to do. On the other hand, if pressure bonding and temporary curing are individually performed on a small substrate, a positioning operation must be performed for each small substrate.

  Therefore, the present invention solves the above problems, and the problem is to reduce the misalignment between the substrates and to reduce the warpage and dent of the substrate constituting the liquid crystal cell, so that an accurate and uniform cell gap can be obtained. An object of the present invention is to provide a method for manufacturing a liquid crystal display device that can be formed.

  In order to solve the above-mentioned problem, the means taken by the present invention is to provide a method for manufacturing a liquid crystal display device in which two substrates are bonded via a sealing material and liquid crystal is injected between the substrates. A pre-curing step for semi-curing the sealing material in a state where the substrate is pressure-bonded to the other substrate through the uncured sealing material at a predetermined pressure, and two sheets pressure-bonded in the pre-curing step And a main curing step of curing the sealing material in a state where the pressure is released with respect to the substrate.

  According to this means, the sealing material is semi-cured in a state where the two substrates are pressure-bonded at a predetermined pressure in the temporary curing step, and then the sealing material is cured in a state in which the pressure is released in the main curing step. The substrate deformed by the pressure at the time of pressure bonding in the temporary curing process has a substrate shape due to an appropriate binding force of the semi-cured sealing material and a restoring force of the substrate at the time when the temporary curing process is finished and the pressure is released. Since it is properly restored and the deformation of the substrate is corrected, the flatness of the substrate and the uniformity of the cell gap in the formed liquid crystal cell can be improved by curing the sealing material without applying pressure in the subsequent main curing process. Can be secured.

  Here, in the temporary curing step, the sealing is performed so that the substrate becomes substantially flat after the pressure is released after the temporary curing step is completed with respect to the pressure, or the substrate is slightly warped. The sealing material is preferably semi-cured by adjusting the degree of curing of the material.

  According to this means, the flatness of the substrate and the uniformity of the cell gap in the liquid crystal cell after completion of the temporary curing step can be controlled by adjusting the degree of curing of the sealing material with respect to the pressure applied in the temporary curing step. Can do. If the degree of curing of the sealing material is low, the binding force of the sealing material becomes weak, so that the restoring force of the substrate is superior, and it becomes difficult to control the flatness of the substrate. On the other hand, when the degree of curing of the sealing material increases, the binding force of the sealing material increases, and the shape of the substrate in the crimped state is strongly reflected. Therefore, if the substrate is deformed during crimping, the deformation remains, and If the substrate is not deformed as much as possible at the time of crimping, there is a high possibility that the original distortion of the substrate is reflected or a substrate seal failure occurs.

  Further, in the temporary curing step, one of the substrates is pressure-bonded to the other substrate through the uncured sealing material at a predetermined pressure, and the one substrate is aligned with the other substrate. It is preferable to include an alignment step of performing a semi-curing step of semi-curing the sealing material in a state where the sealing material is pressurized at substantially the same pressure as the predetermined pressure.

  According to this means, alignment is performed in a state where one substrate and the other substrate are bonded in the alignment stage, and in the subsequent semi-curing stage, the pressing force during the alignment is almost the same with almost no change. Since the sealing material is cured in a pressure-bonded state, it is possible to suppress the occurrence of misalignment after alignment, thereby preventing misalignment between the substrates and improving the accuracy and uniformity of the substrate spacing. be able to.

  In this case, the method further includes an alignment step of roughly aligning one of the substrates with the other substrate in a state where the pressure is lower than the predetermined pressure before the alignment step. Is desirable.

  According to this means, since the alignment is performed in a state where the pressure bonding is performed at a low pressure, the alignment is performed without greatly deforming the sealing material and without applying a large stress. Therefore, accurate alignment can be performed quickly and without affecting the sealing performance of the seal portion.

  On the other hand, the sealing material has photo-curing property, and in the main curing step, the substrate is disposed on a light-transmitting cooling stage, and passes through the cooling stage to seal the seal from the cooling stage side. It is preferable to irradiate the material with light.

  According to this means, since light is irradiated from the side where the cooling is performed by the cooling stage, the cooling efficiency of the liquid crystal cell is increased, and the photocuring treatment can be performed without overheating the liquid crystal cell.

  Further, the sealing material has photocurability, and in the main curing step, light is applied to the sealing material from one substrate side, and light is applied to the sealing material from the other substrate side. Preferably, the step of irradiating.

  According to this means, the liquid crystal cell is irradiated with light from both the front and back sides as separate stages, so that the curing efficiency of the sealing material can be increased, and as a result, the liquid crystal cell can be overheated quickly. It is possible to carry out the photocuring treatment without causing it.

  Furthermore, it is preferable that the sealing material has photocurability, and in the main curing step, the sealing material is irradiated with light that is intermittently increased or decreased at a predetermined frequency.

  According to this means, it is possible to prevent overheating of the liquid crystal cell by appropriately setting the light intensity and frequency with respect to the liquid crystal cell by irradiating with light that is intermittently increased or decreased at a predetermined frequency. .

Further, in order to solve the above-mentioned problems, the means taken by the present invention is to place one of a pair of substrates disposed via a photo-curable sealing material on a translucent stage and A method of manufacturing a liquid crystal display device to be attached to a substrate of the substrate, wherein the sealing material is irradiated with light from the other substrate side, and then the sealing material from the one substrate side through the stage. And irradiating with light.
In this case, it is preferable that the irradiation of the light applied to the one substrate or the irradiation of the light applied to the other substrate is performed intermittently.
Further, it is preferable that the stage includes a cooling mechanism, and the light is applied to the sealing material while the stage is cooled by the cooling mechanism.
Moreover, it is preferable to irradiate the sealing material with light while blowing cooling air to the other substrate. The other substrate is preferably smaller than the one substrate, and a plurality of the other substrates are attached to the one substrate.

Further, in order to solve the above-mentioned problems, the means taken by the present invention is to place one substrate on a stage and attach it to the other substrate through a photocurable sealing material. A liquid crystal display manufacturing apparatus, comprising: a plurality of light sources that irradiate light for curing the sealing material; a first stage on which the one substrate is placed; and a second stage having translucency. The plurality of light sources are opposite to the side on which the one substrate is placed with respect to the first stage and the side on which the one substrate is placed with respect to the second stage The pair of substrates is placed on the first stage and the seal material is irradiated with the light, and then the pair of substrates is placed on the second stage, Irradiating the light to the sealing material through a stage To.
In this case, it is preferable that at least one of the first and second stages includes a cooling mechanism.
The cooling mechanism preferably cools the stage by circulating cooling water inside the stage.
Moreover, it is preferable to further provide a cooling nozzle that blows cooling air onto the pair of substrates.

As described above, the present invention has the following effects.
The sealing material is semi-cured in a state where the two substrates are pressure-bonded at a predetermined pressure in the temporary curing process, and then the sealing material is cured in a state where the pressure is released in the main curing process, so that the pressure-bonding is performed in the temporary curing process. The substrate deformed by the pressure of the time, when the temporary curing process is completed and the pressure is released, the substrate shape is appropriately restored by the moderate binding force of the semi-cured sealing material and the restoring force of the substrate, the substrate Therefore, the flatness of the substrate and the uniformity of the cell gap in the formed liquid crystal cell can be ensured by curing the sealing material without applying pressure in the subsequent main curing step.

  By adjusting the degree of curing of the sealing material with respect to the pressure applied in the provisional curing step, the flatness of the substrate and the uniformity of the cell gap in the liquid crystal cell after the termination of the provisional curing step can be controlled. If the degree of curing of the sealing material is low, the binding force of the sealing material becomes weak, so that the restoring force of the substrate is superior, and it becomes difficult to control the flatness of the substrate. On the other hand, when the degree of curing of the sealing material increases, the binding force of the sealing material increases, and the shape of the substrate in the crimped state is strongly reflected. Therefore, if the substrate is deformed during crimping, the deformation remains, and If the substrate is not deformed as much as possible at the time of crimping, there is a high possibility that the original distortion of the substrate is reflected or a substrate seal failure occurs.

  Alignment is performed in a state where one substrate and the other substrate are pressed in the alignment stage, and in the subsequent semi-curing stage, the seal is applied with almost the same pressure without changing the pressure during alignment. Since the material is cured, the occurrence of misalignment after alignment can be suppressed, so that misalignment between the substrates can be prevented and the accuracy and uniformity of the substrate spacing can be improved.

  Since the alignment is performed in a state where the pressure is pressed at a low pressure by the alignment step, the alignment can be performed quickly without greatly deforming the sealing material and without applying a large stress. Accurate alignment can be performed without affecting the sealing performance of the seal portion.

  Since light is irradiated from the side where the cooling is performed by the cooling stage, the cooling efficiency of the liquid crystal cell is increased, and the photocuring treatment can be performed without overheating the liquid crystal cell.

  Since the liquid crystal cell is irradiated with light from both the front and back sides, the curing efficiency of the sealing material can be increased. As a result, the photocuring process can be performed quickly and without overheating the liquid crystal cell. It becomes possible to do.

  By irradiating light that is intermittently increased or decreased at a predetermined frequency, by appropriately setting the light intensity and frequency for the liquid crystal cell, it is possible to prevent overheating of the liquid crystal cell.

  Next, embodiments according to the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a schematic structure of an embodiment of a manufacturing apparatus (substrate bonding apparatus) for a liquid crystal display device according to the present invention.

  In this embodiment, a buffer material 11 is placed on the upper surface of the XY table 10, and a large-sized substrate 31 made of glass or the like is disposed on the surface of the buffer material 11. On the surface of the large-sized substrate 31, a sealing material 32 made of an ultraviolet curable resin is previously applied by a dispenser or the like so as to surround the liquid crystal sealing region. This sealing material is mixed with a spacer (not shown). On the sealing material 32, a small substrate 33 made of glass or the like is pressure-bonded by the pressure-bonding head 20 described later, and then the sealing material 32 is in a semi-cured state.

  The pressure-bonding head 20 can be moved up and down by a lifting mechanism (not shown) and a pressurizing mechanism using hydraulic pressure, air pressure, etc., and can apply a controlled pressure between the large substrate 31 and the small substrate 33. It is configured. The crimping head 20 is provided with a θ alignment mechanism for making itself rotatable about a vertical axis. The θ alignment mechanism and the adjustment of the XY table 10 in the X direction and the Y direction are provided. It is comprised so that the alignment mentioned later may be performed with a mechanism.

  The pressure-bonding head 20 includes a pressure-bonding base 21 made of a light-transmitting material such as glass, and a light-transmitting plate 24 made of a light-transmitting material such as glass and stacked on the pressure-bonding base 21 via a packing 23. A plurality of alignment cameras 25 arranged above the translucent plate 24 and light emitted from an ultraviolet lamp for irradiating ultraviolet rays from above the translucent plate 24 are guided by an optical fiber 26a and irradiated. The light irradiation part 26 comprised so that it is comprised roughly.

  On the bottom surface of the crimping base 21, a pressing surface portion 21a having substantially the same area as the 1.3 inch rectangular small substrate 33 is formed. The pressing surface portion 21a includes a frame-like portion formed on the outer edge of the bottom surface portion of the pressure-bonding base 21 so as to contact the upper surface of the contact area of the small substrate 33 with respect to the sealing material, and an intake recessed portion formed on the inside thereof. Is provided. The intake recess communicates with an intake hole 21b formed so as to vertically penetrate substantially the center of the crimping base 21. The peripheral portion of the pressing surface portion 21a of the crimping base 21 is covered with the light shielding plate 22, and when the sealing material to be described later is semi-cured, another sealing material corresponding to the other small substrate 33 is cured. It is preventing.

  The upper opening of the intake hole 21 b opens in a gap provided between the light transmissive plate 24, and this gap communicates with the intake hole 24 a provided in the light transmissive plate 24. The intake hole 24a is formed at a position shifted outward from the planar position of the pressing surface portion 21a, and is connected to an exhaust pipe 27 connected to an exhaust device (not shown). The intake hole 21b, the gap portion, and the intake hole 24a constitute an intake passage that is formed so as to be disengaged from the planar position of the pressing surface portion 21a.

  When an exhaust valve (not shown) of the exhaust device is opened, air is exhausted from the intake recess through the intake passage composed of the intake hole 21b, the gap and the intake hole 24a. For this reason, the small substrate 33 can be adsorbed to the pressing surface portion 21 a of the crimping base 21.

Next, the operation of the apparatus having the above structure will be described.
First, the small substrate 33 is attracted and held on the pressing surface portion 21a at a material supply position (not shown), and then the pressure-bonding head 20 is moved onto the large substrate 31 and lowered in accordance with the position of the seal material 32 applied in advance. Next, the pressure-bonding head 20 is lowered so that the outer edge portion of the small substrate 33 is in contact with the sealing material 32, and the small substrate 33 is pressed against the large-sized substrate 31.

  When the position of the pressure bonding head 20 is stabilized, the position of the XY table is corrected by the alignment camera 25 so that alignment marks (not shown) of the small substrate 33 and the large size substrate 31 are aligned. Thus, by aligning the rotation direction of the crimp base 21, the alignment is performed so that the small substrate 33 is crimped to the large substrate 31 at a regular position.

  Next, the sealing material is semi-cured by irradiating ultraviolet rays from the light irradiation unit 26. As will be described later, the degree of curing of the sealing material is set according to the degree of warpage or dent of the glass substrate, particularly the small substrate 33 in the liquid crystal cell to be formed. When the semi-curing of the sealing material is finished, the exhaust valve (not shown) of the exhaust device is closed and the pressure-bonding head 20 is raised to separate the pressing surface portion 21a from the small substrate 33. In this manner, the above-described apparatus is configured to sequentially press-bond a plurality of small substrates 33 to predetermined positions on the large substrate 31.

  FIG. 2 shows the pressure state of the pressure-bonding head 20. When the pressure-bonding head 20 is lowered and the small substrate 33 is pressure-bonded to the large-sized substrate 31, the pressure-bonding head 20 first holds the pressure substrate at a pressure of about 4 kg. Step (a) for alignment for performing rough position correction is executed. For example, in this step (A), the positional displacement of the small substrate 33 with respect to the normal position on the large substrate 31 is within 5 μm using the alignment camera 25 or other position sensor. To correct. The processing time of this step (A) is about 1 second.

  Next, the pressure force of the pressure bonding head 20 is increased to about 8 kg, and then kept constant. In this state, the alignment step (b) is executed. In this step (b), using the alignment camera 25, the planar position of the small substrate 33 is corrected with respect to the large substrate 31 so that the error is within 1 μm. The processing time of this step (b) is about 6 seconds.

  Subsequently, the pressure applied by the pressure-bonding head 20 is maintained as it is, and the step (c) for semi-curing the sealing material 32 is executed. In this step (c), ultraviolet rays are irradiated from the light irradiation unit 26, and the sealing material is cured to a predetermined extent within a range where the sealing material is not completely cured. The processing time for this step (c) is about 7 seconds.

  In this embodiment, rough position correction is performed in a state where the substrate is pressed with a small pressure in step (A), and then a high-precision position correction is performed in a state where the final pressure is set in step (B). After that, in step (c), the sealing material is semi-cured by irradiating light without changing the pressurized state.

  In step (a), the position correction is easy because of the low pressure, and a large correction can be easily performed without causing a large deformation in the sealing material and without applying a large stress. In step (b), since alignment is performed with a final applied pressure or a close applied pressure, there is almost no change in the pressure-bonded state between the substrates even after alignment, and the liquid crystal finally finished with pressure bonding. Generation of cell misalignment (shift in the planar direction between two substrates) can be prevented.

  Further, since the applied pressure is hardly changed from step (b) to step (c), the sealing material can be cured while maintaining the alignment accuracy performed in step (b). Here, for example, as shown by a broken line in FIG. 2, when the pressure in step (b) is large and the pressure is reduced in step (c), the substrate is lifted at the seal portion, resulting in poor sealing and cell thickness. Variation, substrate misalignment, etc. occur. On the contrary, as shown by the dotted line in FIG. 2, when the pressing force in step (c) is increased over the pressing force in step (b), the pressing force is increased thereafter even if the corner alignment is performed in step (b). As a result, there is a drawback in that the miscombination occurs again in step (c).

  In the present embodiment, when the small substrate 33 is pressed by the crimping base 21, the small substrate 33 is deformed downward (dent), and the large substrate 31 is also deformed downward by the deformation of the cushioning material 11. Deforms into a convex shape. When the pressure applied by the pressure bonding head 20 is somewhat large, the deformation amount of the large substrate 31 becomes larger than the deformation amount of the small substrate 33. Therefore, as shown on the left side of FIG. At the time of pressurization by 20, the cell gap becomes large at the center of the liquid crystal cell. If the applied pressure is released in this state, the sealing material is incompletely cured, so that there is a certain degree of binding force against the deformation of the substrate, and the applied force causes the substrate to be forcibly deformed. As shown in the right side of FIG. 3 (a), the substrate is reduced in warping and becomes almost flat, and the cell gap of the liquid crystal cell is made uniform. The

  However, as shown on the left side of FIG. 3B, if the applied pressure is too large and the amount of warping of the large substrate 31 increases, the applied pressure after curing of the sealing material is increased as shown on the right side of FIG. Even when released, the substrate may remain warped. In addition, the remaining warpage of the substrate occurs in the same manner because the deformation of the substrate in the pressurized state is difficult to be eliminated by the binding force of the sealing material, particularly when the sealing material is excessively cured. .

  Unlike this embodiment, when the small substrates are pressure-bonded to each other, or when a plurality of small substrates are pressed by a large and flat integrated pressing surface portion on the large substrate, a different aspect from the present embodiment is obtained. Present. In other words, the upper substrate is deformed in a downward convex shape by the pressure applied during crimping, but when the small substrates are crimped, almost no force is generated to deform the lower substrates, and more than one small When the substrate is integrally pressed on the large substrate, the force for deforming the lower substrate is weak, and in any case, the deformation amount of the lower substrate is small, as shown on the left side of FIG. In addition, the cell gap at the center of the liquid crystal cell is smaller than the surroundings. When the applied pressure is released in this state, as shown on the right side of FIG. 3C, the upper substrate is deformed from the recessed state to the warped state when released.

  When the pressure force of the pressure bonding head 20 is small, as shown on the left side of FIG. 3D, the substrate is almost flat and the cell gap is uniform. Due to the provided distortion or the like, the substrate may be slightly warped or may be recessed as shown on the right side of FIG.

  On the contrary, if the pressure force of the pressure bonding head 20 becomes considerably large, the substrate is greatly depressed as shown on the left side of FIG. 3E. In this state, if the curing of the sealing material 32 is excessively advanced, Even if is released, as shown on the right side of FIG.

  As described above, in the present embodiment, the sealing material is semi-cured to restore the deformation of the substrate when the applied pressure is released. Therefore, even if the substrate is slightly warped during pressurization, the liquid crystal cell Distortion can be reduced. Therefore, without worrying about deformation of the liquid crystal cell, it is possible to apply a certain amount of pressure in order to surely obtain a desired cell gap at the time of pressure bonding, and it is possible to reduce the pressure bonding failure of the substrate.

  The amount of restoration at the time of releasing the above-mentioned applied pressure varies depending on the degree of curing of the sealing material. FIG. 4 shows the relationship between the amount of warpage of the liquid crystal cell and the light irradiation time in this embodiment. In the present embodiment, if the light irradiation time to the sealing material is too short, the binding force of the substrate by the sealing material is too small, and the amount of warpage (or the amount of dents) of the substrate due to the original distortion of the small substrate 33. There will be more variation. On the other hand, if the light irradiation time to the sealing material is too long, the sealing material is hardened too much and the binding force becomes large, the warping state of the substrate at the time of pressurization is maintained, and the liquid crystal cell exhibits a large warping. Become.

  In the region A shown in FIG. 4, the amount of warpage of the substrate is small, and variation in the amount of warpage is small, and a stable cross-sectional shape of the liquid crystal cell can be obtained. In this case, in the region A, the substrate is slightly warped, and the formed liquid crystal cell has a slightly larger cell gap at the center. However, when the liquid crystal display is formed, it is more preferable that the substrate is slightly warped in an empty cell state than when the substrate is completely flat. This is because in the subsequent liquid crystal injection step, the liquid crystal cell is depressurized and liquid crystal is injected by the pressure difference between the inside and outside, so that the liquid crystal can be injected more smoothly if the substrate is slightly warped. Moreover, there is a tendency that a substantially flat liquid crystal cell is formed after liquid crystal injection.

  FIG. 5 shows the amount of warpage of the liquid crystal cell and the light irradiation to the sealing material when the small substrates are pressure-bonded to each other or when a plurality of small substrates are pressed on the large substrate by a large and flat integrated pressing surface portion. Shows the relationship with time. Here, the region above the horizontal axis shows the case where the substrate is warped, and the region below the horizontal axis shows the case where the substrate has a dent.

  In this case, the amount of warpage of the liquid crystal cell decreases almost linearly by increasing the light irradiation time to the sealing material, and the formed liquid crystal cell eventually exhibits a cross-sectional shape with a recessed central portion. It becomes like this. Also in this case, it is preferable to set the degree of cure of the sealing material so that the amount of warpage of the liquid crystal cell is small by adjusting the light irradiation time as shown as a region B in FIG. In addition, the dotted line in FIG. 5 shows the curvature amount when the pressurizing force of the crimping head is increased.

  The liquid crystal cell temporarily cured as described above is fully cured in a free state where no pressure is applied. This main curing process is performed by being divided into a first stage shown in FIG. 6 and a second stage shown in FIG. In this step, by completely curing the sealing material, the shape of the liquid crystal cell formed in an almost ideal state in the temporary curing step is hardly deformed so as to withstand external force. Further, as will be described later, by performing the process with an apparatus having a cooling mechanism in the process, it is possible to suppress overheating of the substrate and prevent positional displacement of the substrate that occurs when the sealing material is cured.

  In the first stage, as shown in FIG. 6, a liquid crystal cell in which a plurality of small substrates 33 are bonded to a large substrate 31 via a sealing material 32 is placed on the surface of the cooling stage 40, Ultraviolet rays are irradiated from above by an ultraviolet lamp 41. The cooling stage 40 is made of a surface material with high thermal conductivity, and cooling water circulates inside the cooling stage 40 to constantly cool the stage surface. From obliquely above the liquid crystal cell, cooling air is blown from the air nozzle 42 along the installation surface of the liquid crystal cell. These entire curing devices are sealed with a hood or a casing of the device, and an exhaust duct (not shown) is attached.

  This first step is conductive to cure a photocurable conductive resin (such as kneaded conductive particles in a photocurable resin) applied on an electrode pad on a large substrate 31 of a liquid crystal cell. This is mainly provided because it is necessary to irradiate light from the small substrate 33 side so that the resin does not become a shadow of the electrode pad. However, in this first stage, the curing of the sealing material 32 proceeds at the same time.

  In the second stage, as shown in FIG. 7, a liquid crystal cell is placed on a light-transmissive cooling stage 50, and an ultraviolet lamp 55 is placed on the back side of the cooling stage 50 to irradiate light. It has become. The cooling stage 50 fixes the cooling performance by fixing the translucent plates 51 and 52 made of glass or the like through the packing 53 and circulating the cooling water between the translucent plates 51 and 52. It is supposed to have translucency while ensuring. The air nozzle 54 blows cooling air onto the small substrate 33 in the same manner as described above, and the apparatus is also sealed from the surroundings and includes an exhaust duct as described above.

  In this second stage, light is irradiated from the large-sized substrate 31 side of the liquid crystal cell and the light irradiation side is mainly cooled, so that the cooling efficiency is better than in the first stage and the liquid crystal cell is overheated. The sealing material 32 can be cured without causing it.

  As described above, the curing process is divided into the first stage and the second stage, and the light irradiation efficiency to the sealing material 32 can be improved by irradiating light from both the front and back surfaces of the liquid crystal cell. Can be uniformly cured in a short time. In addition, since the photocuring of the sealing material can be efficiently performed in this way, it is possible to prevent overheating of the liquid crystal cell.

  In the main curing step, the liquid crystal cell is prevented from being overheated by cooling as described above and further by intermittently irradiating light from the ultraviolet lamps 41 and 55. In the present embodiment, as shown by the dotted line in FIG. 8, light irradiation is intermittent at a cycle of 100 seconds. As a result, the temperature of the liquid crystal cell periodically rises and falls as shown by a solid line in FIG. 8, and the temperature does not rise unnecessarily as in the conventional case even if irradiation is continued for a long time. For this reason, even if the amount of light irradiation is increased, overheating of the liquid crystal cell can be prevented.

  The intermittent period of light irradiation is appropriately set according to the heat dissipation of the liquid crystal cell. By optimizing the intermittent period and the light irradiation intensity, curing can be completed quickly without overheating the liquid crystal cell. This light irradiation does not necessarily need to be intermittent, and the same effect can be obtained by increasing or decreasing the light irradiation intensity.

  In the manufacturing method of the above embodiment, the present invention is applied to a manufacturing process that is set so that a plurality of small substrates are crimped to a large substrate, but the present invention is limited to application to such a manufacturing process. It can be applied to a manufacturing process for crimping large substrates including a plurality of liquid crystal displays, and a manufacturing process for crimping small substrates for constituting a single liquid crystal display, For example, as described with reference to FIGS. 3C to 3E and FIG. 5, a plurality of small substrates can be bonded at once, or flat pressing surface portions can be bonded. The present invention can also be applied to a manufacturing process configured to be crimped by a crimping head provided.

  The method employed in the present embodiment is a method in which the sealing material is pressed by the pressure-bonding head by allowing a certain degree of restraining force to prevent the complete restoration while allowing the restoration of the substrate to some extent. The substrate deformed by the process is restored to some extent when the pressure is released, and a flat cell shape is formed as much as possible in the restored state. By such a method, a more ideal cell shape can be obtained with good reproducibility. be able to.

It is a schematic block diagram which shows embodiment of the manufacturing apparatus of the liquid crystal display device which concerns on this invention. It is a time chart which shows the applied pressure of the temporary hardening process in embodiment of the manufacturing method of the liquid crystal display device which concerns on this invention. It is a conceptual explanatory drawing (a)-(e) for demonstrating the cross-sectional shape of the liquid crystal cell at the time of the pressurization of a temporary hardening process, and after pressurization release. It is a graph which shows the relationship between the curvature amount of the liquid crystal cell in the said embodiment, and the light irradiation time of a temporary hardening process. It is a graph which shows the relationship between the curvature amount of the liquid crystal cell in the method different from the said embodiment, and the light irradiation time of a temporary hardening process. It is an apparatus block diagram which shows the process state in the 1st step of the main hardening process in the said embodiment. It is an apparatus block diagram which shows the process state in the 2nd step of the main hardening process in the said embodiment. It is a graph which shows the light irradiation cycle of the main hardening process in the said embodiment, and the temperature change of a liquid crystal cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 XY table 11 Buffer material 20 Crimp head 21 Crimp base 21a Press surface part 21b Intake hole 24 Translucent plate 24a Intake hole 25 Alignment camera 26 Light irradiation part 27 Exhaust pipe

Claims (4)

A method of manufacturing a liquid crystal display device in which one of a pair of substrates disposed via a photocurable sealing material is placed on a translucent stage and adhered to the other substrate,
Irradiating the sealing material with first light from the other substrate side;
After that, while cooling the sealing material, the second light is intermittently applied to the sealing material through the stage from the light irradiation unit disposed on the one substrate side and irradiating the whole pair of substrates. A curing step of irradiating
In the curing step, the stage on the second light irradiation side is cooled by circulating cooling water therein, and the method for manufacturing a liquid crystal display device is characterized. A method of manufacturing a liquid crystal display device in which one of a pair of substrates disposed via a photocurable sealing material is placed on a translucent stage and adhered to the other substrate,
Irradiating the sealing material with first light from the other substrate side;
Thereafter, a curing step of irradiating the sealing material with the second light from the one substrate side through the stage while increasing or decreasing the light irradiation intensity while cooling the sealing material,
In the curing step, the stage on the second light irradiation side is cooled by circulating cooling water therein, and the method for manufacturing a liquid crystal display device is characterized.   3. The method of manufacturing a liquid crystal display device according to claim 1, wherein the sealing material is irradiated with light while blowing cooling air to the other substrate. 4. The method of manufacturing a liquid crystal display device according to claim 1, wherein the other substrate is smaller than the one substrate, and the plurality of the other substrates are adhered to the one substrate.

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