JP4789337B2 - Method for manufacturing liquid crystal display device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a configuration of a liquid crystal display device.
[0002]
[Prior art]
A liquid crystal display device is a light-weight and thin display device that is advantageous in terms of low power consumption, and is widely used for business in portable terminals such as notebook personal computers, and in homes as monitors for personal computers and flat-screen TVs. Nowadays, it is steadily replacing CRT, which has played an active role as a leading player in display devices.
[0003]
In general, a display device is a means that can reversely convert an electrical signal into an optical signal and reconstruct it into an image or the like so that information such as an image that has been converted into an electrical signal and transferred can be visually recognized. Many such display devices have been devised so far, and a liquid crystal display device is one of them.
[0004]
Display devices are roughly divided into two types depending on how light is used. The two are a method of applying a material that emits light to the display unit of the display device, such as a CRT, and the display unit does not emit light, but another light source is obtained, and the luminance of the light source light is controlled by the display unit in some way This is a method that allows you to A normal liquid crystal display device belongs to the latter. The liquid crystal display device in the invention described in this specification basically uses this normal liquid crystal display device as an example. However, the invention described in this specification can be used as it is in the technical field even for a self-luminous liquid crystal display device. However, in the current technical trend, the liquid crystal display device can be classified as a non-light-emitting type, and therefore, a non-light-emitting type liquid crystal display device will be described as an example.
[0005]
The liquid crystal display device uses the electrical and optical anisotropy of the liquid crystal to provide a mechanism that can control the transmission and non-transmission of light emitted from the light source as an electrical shutter and bulb. The applied electrical image signal can be visualized.
[0006]
An outline of the liquid crystal display device is shown in FIG. 4. In order to realize this, the liquid crystal display device combines a polarizing plate 401, a liquid crystal cell 402, a backlight 403, and the like as necessary, and an integrated liquid crystal display is used as the liquid crystal display device. As a display device, it is incorporated into a display unit and used.
[0007]
3A and 3B schematically show the structure of a cross-sectional view and a top view of a conventional liquid crystal display device. The liquid crystal is held at a constant interval of about 10 μm or less between the substrate 301 and the substrate 302, each of which has a light-transmitting property, and the liquid crystal is sandwiched therebetween. Further, in order to apply an electric field to the liquid crystal on the pair of substrates, a counter electrode 308 made of a conductive thin film is formed on the surface of the substrate (the electrodes on the substrate 301 and the liquid crystal are not shown).
[0008]
In order to visualize the electrical signal applied to the liquid crystal, the liquid crystal molecules are aligned in a predetermined state in the liquid crystal display device so that the optical anisotropy of the liquid crystal can be used effectively. The method of applying an electrical signal and the alignment of liquid crystal molecules are closely related, and several methods have been proposed so far. In general, a general term for these operation methods is called an operation mode. The typical operation modes are those using a nematic liquid crystal, such as a twisted nematic (TN) mode, a vertical alignment (VA) mode, and a lateral electric field drive (IPS). ) Mode, and those that use smectic liquid crystal such as ferroelectric liquid crystal and anti-ferroelectric liquid crystal, surface stabilized ferroelectric liquid crystal (SSFLC) mode, tristable switching (TSS; Tri-State Switching) mode is known and widely used.
[0009]
In any case, the liquid crystal display devices using these operation modes improve the in-plane uniformity of the transmission characteristics of the liquid crystal display device with respect to the applied voltage for the purpose of realizing and maintaining the uniformity of the image quality. In order to improve the uniformity of the response characteristics of the liquid crystal with respect to the applied voltage in the entire apparatus, the distance between the pair of substrates can be kept uniform.
[0010]
3A and 3B schematically show the structure of a cross-sectional view and a top view of a conventional liquid crystal display device. In order to make the distance between the active matrix substrate 301 and the counter substrate 302 uniform. Have a large number of spray spacers 305 having a uniform size on the substrate in order to counteract the force in the direction of narrowing the interval between the substrates. Moreover, it is a general method to adhere | attach substrates with a sealing material so that substrates may not leave | separate.
[0011]
Specifically, in order to bond the pair of substrates 301 and 302, a linear seal pattern 307 is formed so as to be along the outer peripheral portion of the region where the pair of substrates overlap and to surround at least the pixel portion 303. . The pixel portion corresponds to a pixel region. The sealing material forming the seal pattern 307 is made of an adhesive. The line width of the seal pattern is generally constant, and the line width is set to about 1 mm to 4 mm. The sealing material is an adhesive / sealing material for laminating two substrates and enclosing liquid crystal therein, and is a material disposed in the peripheral portion of the panel. The seal pattern is defined by the shape, position and width of the seal.
[0012]
The seal pattern is not made into a closed curve pattern from the beginning, but a cut part is made. This is the liquid crystal inlet. In order to place the liquid crystal in the liquid crystal display device, liquid crystal is injected from this injection port by a vacuum injection method or the like to fill the liquid crystal in the display device. After all of the liquid crystal is filled in the liquid crystal display device, the inlet is closed with a sealing material 110 or the like so that the liquid crystal does not leak from the inlet.
[0013]
As the sealing material, a resin such as a thermosetting epoxy or a UV resin that is cured by ultraviolet rays is used. However, the sealing material uses an insulating material.
[0014]
[Problems to be solved by the invention]
The liquid crystal filled in the liquid crystal display device is in direct contact with the sealing material. Therefore, the trouble that occurs in the sealing material often affects the liquid crystal as a trouble. Of course, the more portions where the liquid crystal and the resin contained in the sealing material are in contact with each other, the higher the probability of occurrence of a malfunction. The malfunction of the liquid crystal results in the deterioration of the image quality of the liquid crystal display device.
[0015]
However, there has been a case where at least one of the plurality of resin components contained in the sealing material is separated before the sealing material is cured by heat or ultraviolet rays.
[0016]
In the case of the TN liquid crystal, since the liquid crystal has fluidity even in the operating temperature range, impurities generated from the sealing material may melt and be included in the liquid crystal as it is. For example, as shown in FIG. 3, the sealing material 313 separated into the liquid crystal is present in the pixel portion 303.
[0017]
If this impurity component is highly soluble in the liquid crystal, it will be dissolved in the liquid crystal, so that it is difficult to grasp its presence with the naked eye, but this will cause a decrease in the electrical insulation of the liquid crystal. When the insulating property of the liquid crystal is lowered, the voltage is not effectively applied to the liquid crystal, so that the image quality such as the contrast is lowered.
[0018]
When the impurity component is not soluble in the liquid crystal, a resin region exists in a region filled with the liquid crystal. If there is no solubility, it is expected that almost no liquid crystal is contained in the resin region. Therefore, the resin-only region is isolated in the liquid crystal, or is partially in contact with the seal pattern or separated. It exists in a state where a plurality of resins are in contact.
[0019]
Since the resin contained in the sealing material is nonpolar and the dielectric anisotropy can be regarded as almost zero, when the drive electric field is applied in this state, the resin reacts to the electric field at all. do not do. It seems that there is a region in the liquid crystal that does not respond to the electric field. This is recognized as a black spot defect in a TN liquid crystal of a so-called normally white display that is in a white display state when no electric field is applied.
[0020]
However, this is a case where the size of the separated resin is relatively large, about 0.1 to 1 mm in diameter. If the diameter is smaller than this, the resin moves due to the turbulent flow of the liquid crystal around the resin due to the response of the liquid crystal. May look like.
[0021]
On the other hand, when a smectic liquid crystal typified by a ferroelectric liquid crystal or an anti-ferroelectric liquid crystal is used, another problem occurs. That is, the linear shape of the interface between the sealing material and the liquid crystal as viewed from the direction in which the display portion can be seen affects the alignment of the liquid crystal.
[0022]
In the case of a material such as a ferroelectric liquid crystal or an antiferroelectric liquid crystal, the viscosity of the liquid crystal at room temperature is considerably higher than that of a nematic material, and therefore the liquidity of the liquid crystal is very poor. If the alignment of the liquid crystal is partially disturbed due to the unevenness on the side surface, the alignment at that location remains disordered. When the region where the orientation is disturbed spreads over the pixel portion, the contrast of the portion is significantly lowered.
[0023]
In this way, it can be seen that the linear shape of the boundary between the sealing material and the liquid crystal as viewed from the direction in which the display portion can be seen is very important. When it is used with a thickness of about 2 μm, as shown in FIG. 3, the exudation 314 of unnecessary sealing material spreads like a whisker from the side of the original pattern as shown in FIG. In severe cases, the unnecessary leakage of the sealing material 314 may spread to the area of the pixel portion 303.
[0024]
This phenomenon is considered as follows. In the hot pressing step after superposition, the panel temperature is generally heated to 150 to 200 ° C. to advance the curing reaction, and when the curing is completed, the panel temperature is lowered to room temperature. At 150 ° C to 200 ° C, the viscosity of the adhesive decreases just before the curing reaction starts, and it becomes a fairly fluid state, so that it adheres to the part where the distance between the substrates is thin due to capillary action. The adhesive begins to flow, and when the time further elapses, the curing reaction starts, so the viscosity of the adhesive suddenly increases, and the adhesive that has once spread solidifies without returning to its original state. End up. This phenomenon was particularly remarkable when the distance between the substrates was reduced.
[0025]
To solve this problem, the resin material is mixed with a roughly spherical material having an average particle diameter of about 3 μm to 4 μm (hereinafter referred to as “filler”), and the apparent viscosity is increased to lower the viscosity when the panel is heated. However, in the case where the distance between the substrates has to be made thinner, there is a contradiction that the distance between the substrates cannot be reduced because the filler becomes an obstacle. It may be necessary to use a sealant that uses a filler with a small average particle size, but in reality, an adhesive with a filler with an average particle size of 3 μm or less has not been completed and used. Not done. In any case, it did not lead to a fundamental solution.
[0026]
For this reason, there has been a demand for a structure that can prevent the adverse effect on the alignment of the pixels due to the diffusion of the resin into the liquid crystal and the disorder of the linear shape of the sealant / liquid crystal boundary and improve the contrast.
[0027]
On the other hand, there is a concern about contamination of the external lead-out wiring section and the FPC attached to the external lead-out wiring section due to deterioration of the sealing material due to external moisture and the like.
[0028]
[Means for Solving the Problems]
The present invention has been devised to solve the above problems. That is, the invention of the present specification includes a pair of substrates at least one of which is transparent, a seal pattern inside the end surfaces so as to be parallel to the end surfaces of the pair of substrates, and an area surrounded by the seal patterns. The liquid crystal display device includes a first partition and a second partition so as to be parallel to the seal pattern on the inside, outside, or both sides, and a liquid crystal so as to be in contact with the seal pattern or the first partition. In this specification, the partition refers to a partition shaped like a wall, the first partition partitions the liquid crystal and the sealing material, and the second partition partitions the sealing material and the air outside the liquid crystal display device. . This partition corresponds to a gap material, and the first partition and the second partition correspond to an inner gap material and an outer gap material, respectively. Further, the first partition is a material for orienting the liquid crystal, and the second partition provided outside protects the sealing material. By providing the first partition in order to maintain the alignment state of the liquid crystal inside the seal pattern, the contrast can be improved by reducing the alignment disorder of the liquid crystal. In addition, by providing the second partition wall, there is an effect that contamination of the external lead-out wiring portion and the FPC due to deterioration of the sealing material due to moisture or the like outside the seal pattern can be prevented.
[0029]
In order to solve the above problem, a columnar spacer may be provided inside the first partition of the liquid crystal display device of the present invention. By providing columnar spacers in addition to the first partition and the second partition, a liquid crystal display device with little variation in gap between the substrates (gap unevenness) can be provided. This columnar spacer corresponds to a gap retaining material.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
1A and 1B are a cross-sectional view and a top view of a liquid crystal display device of the present invention. 2A and 2B are a cross-sectional view and a top view of the liquid crystal display device of the present invention. Here, a case where the present invention is applied to an active matrix liquid crystal display device will be described as an example. Here, as an example, the drive circuit is formed on the same substrate in the active matrix substrate. 101 is an active matrix substrate, and 102 is a counter substrate. Reference numeral 103 denotes a pixel portion, 104 denotes a driving circuit (gate driver) for controlling the pixel portion 103, 105 denotes a scattering spacer, 106a denotes a first partition, 106b denotes a second partition, 107 denotes a seal pattern, and 108 denotes a counter electrode 109 are alignment films. In FIG. 1, the liquid crystal is not shown for the purpose of explaining the internal structure of the liquid crystal display device according to the present invention. However, the active matrix substrate 101 and the counter substrates 102 and 106a are actually the first partition walls and the seal pattern. The space formed by 107, the alignment film 109, and the sealing material 110 is filled with liquid crystal. The pixel portion corresponds to a pixel region.
[0031]
In the active matrix substrate 101, pixel electrodes and signal electrodes are formed on a light-transmitting substrate. The substrate is made of an alkali-free glass or a quartz substrate. Note that a flexible material, for example, a plastic material such as polyimide or polycarbonate may be used as long as it is a light-transmitting substrate. As described above, an active matrix having a known circuit configuration and formed of a known material can be used. The active matrix substrate can be used not only on a glass substrate but also on a Si wafer or a metal substrate.
[0032]
As the active matrix substrate 101, a substrate in which a pixel circuit using active elements is formed, or a substrate in which a drive circuit is formed around the pixel circuit on the same substrate can be used.
[0033]
As the counter substrate 102, a light-transmitting substrate can be used. The substrate is made of an alkali-free glass or a quartz substrate. In addition to this, the substrate may be a flexible material, for example, a plastic material such as polyimide or polycarbonate.
[0034]
As the counter substrate 101, a substrate formed by a known technique such as a liquid crystal display device in which a color filter is patterned on the substrate or a transparent electrode and a black matrix alone is used. I can do it.
[0035]
The alignment film 109 can be made of a material generally used for liquid crystal display devices such as polyimide and polyamide. The material of the alignment film is selected according to the operation mode of the liquid crystal to be used. When the alignment film is applied on the substrate, it is possible to use a printing method or a spinner.
[0036]
Since the alignment film 109 is generally made of an electrically insulating material, the electrode surface is exposed so that the signal electrode formed on the substrate can be electrically connected to the external electric circuit. Pattern. In order to pattern the alignment film, a printing method is desirable. In the case of the printing method, an alignment film pattern is formed in a portion surrounded by a resin pattern.
[0037]
The alignment film 109 is subjected to an alignment process for aligning the liquid crystal. The alignment process is selected according to the operation mode of the liquid crystal to be used. For example, in the TN mode, processing is performed so that the major axis of the liquid crystal molecules is parallel to the substrate. Moreover, you may utilize the photo-alignment process using an ultraviolet-ray etc.
[0038]
Next, the sealing material, the first partition, and the second partition will be described. First, as the sealing material, an adhesive material is used for the purpose of finally sealing the liquid crystal between the substrates so as not to leak to the outside and bonding the pair of substrates to each other.
[0039]
Examples of the sealing material include an epoxy resin and an acrylic resin as the material having adhesiveness. The curing method may be either a thermosetting type or a photocuring type.
[0040]
In addition, in order to make the space | interval of a board | substrate constant, you may add the additive which is hard to receive the deformation | transformation with respect to a sealing material as needed. When this is used when the distance between the substrates is approximately 3 μm or more, it is effective in reducing the variation in the distance between the substrates with respect to the distance between the substrates in the liquid crystal display device. At this time, as the additive, a spacer having a spherical or cylindrical shape and a constant diameter is used. As the additive, an inorganic material such as SiO2 or an organic material mainly composed of divinylbenzene can be used.
[0041]
The diameter of the spacer added at this time is appropriately selected depending on the liquid crystal to be used or the operation mode. For example, in the TN mode, about 4 to 5 μm, and for the ferroelectric liquid crystal and antiferroelectric liquid crystal, about 0.5 to 3 μm.
[0042]
The amount added to the resin depends on the spacer used, but in many cases it may be about 3%. If too much is added, the added spacers overlap each other, and a certain distance between the substrates cannot be obtained.
[0043]
Next, the first partition wall 106a and the second partition wall 106b will be described. The first partition wall 106a provided inside the seal pattern 107 is formed between the seal material and the liquid crystal in order to prevent a malfunction of the seal material, that is, separation of components or unnecessary spread from the pixel portion. A material which is between the substrates and formed between the seal pattern 107 and the liquid crystal is a first partition wall 106a. The first partition 106a corresponds to the inner gap material. The first partition wall 106a may be formed so as to surround the liquid crystal in all the inner portions surrounded by the seal pattern, or only a part thereof. In order to prevent deterioration due to moisture outside the liquid crystal display device, a material provided outside the seal pattern is a second partition wall 106b. The second partition 106b corresponds to an outer gap material. The second partition wall 106b may be formed in all parts outside the seal pattern 107, or only a part thereof.
[0044]
As long as the first partition wall 106a and the second partition wall 106b can be processed into a predetermined shape, any of an inorganic material, an organic material, or a mixture thereof can be used. In particular, the first partition 106a preferably has liquid crystal resistance, and the second partition 106b preferably has water resistance. In addition, a photolithography method, a printing method, a dispensing method, or the like may be used for forming the first partition wall 106a and the second partition wall 106b.
[0045]
When it is desirable that the side surface of the first partition wall 106a has a more linear shape, the first partition wall 106a having a linear side surface when viewed from the direction in which the display portion can be viewed can be formed by photolithography. In the first partition 106a, the side surface refers to a surface in contact with the liquid crystal. In addition, since the mask aligner used when manufacturing the active matrix substrate 101 can be used, the alignment accuracy can be increased. In order to simplify the processing steps, a material that can be patterned by the photolithography method in the first partition wall 106a and the second partition wall 106b is desirable. In this case, a photosensitive resin can be used. For example, an acrylic resin can align molecules in parallel with its side surface by its alignment regulating force, and can realize good liquid crystal alignment. Although a non-photosensitive material such as SiO2 can be used, an extra step of forming the spacer on the SiO2 with a resist or the like as a mask for patterning the spacer and removing the mask after the spacer patterning is completed is required.
[0046]
When the printing method and the dispensing are used, the linear shape of the first partition 106a may be slightly inferior to that of the photolithography method. Instead, a material that forms the first partition 106a and the second partition 106b is used for the substrate. Since it can be formed into a predetermined pattern as it is applied, there is an advantage that the process can be simplified.
[0047]
Note that since the material used for the alignment film is not highly resistant to an alkaline solution such as a developer, the order in which the alignment film is applied and the first partition 106a and the second partition 106b are formed is noted. Should. In the case where the first partition 106a and the second partition 106b are formed by a photolithography method, the first partition 106a and the second partition 106b are formed first, and then an alignment film 109 is applied. On the other hand, in the case of printing method or dispensing, the alignment film may be applied to the substrate before, and then the material constituting the first partition and the second partition may be applied.
[0048]
In addition, the height of the columnar spacer 112 is basically good enough to prevent the seal material from seeping into the pixel portion, but the interval between the opposing pixel electrodes formed on the pair of substrates, that is, It can also be set so that the interval between the substrates can be a predetermined interval. In particular, when the active matrix substrate 101 is used, signal wiring, black matrix, auxiliary capacitance, interlayer insulating film, and the like are formed. In some cases, a step due to these components is generated. Decide. That is, for example, when the interval between the substrates is to be 4 μm, and there is a step 0.2 μm higher than the pixel electrode at the position where the columnar spacer 112 is to be raised, the pressure in the direction of reducing the distance between the pair of substrates in the panel manufacturing process If the deformation is such that the deformation of the first partition wall 106a and the second partition wall 106b may be neglected, the height of the columnar spacer 112 may be 3.8 μm. If the deformation of the first partition 106a and the second partition 106b cannot be ignored, the height of the columnar spacer 112 may be set higher than the final target substrate interval. A columnar spacer corresponds to the gap retaining material.
[0049]
When the columnar spacer 112 is not formed, the spacer is scattered on the substrate as shown in FIG. The spacer is a spherical substance made of an organic substance or an inorganic substance, and those used in conventional liquid crystal display devices can be used as they are. As for the spacer, the density of the spacer in the liquid crystal display device is generally 20 to 200 / mm before the active matrix substrate and the counter substrate are bonded together. ² If so, the distance between the substrates can be kept constant.
[0050]
Note that columnar spacers may also be provided in a portion that does not affect display in the pixel portion, for example, on a source wiring, a gate wiring, or a black matrix, and may be used for holding a distance between substrates. FIG. 3 shows a columnar spacer 112 provided in the pixel portion. In this way, it is not necessary to separately spray spacers.
[0051]
Further, although the case where the spacer is formed on the active matrix substrate 101 is taken as an example, the present invention is not limited to this, and the spacer may be formed on the counter substrate 102 or may be formed on both substrates. However, when the spacer is also formed in the pixel portion, it is desirable to form the spacer on the active matrix substrate by a photolithography method in order to increase the alignment accuracy between the pixel formed on the substrate and the spacer. This is because the mask aligner generally has higher alignment accuracy than the bonding apparatus.
[0052]
In this way, a spacer is formed on either the active matrix substrate or the counter substrate on which the alignment film, the seal pattern, the first partition wall, and the second partition wall are formed, and then bonded to manufacture a liquid crystal display device. Match. If the manufacturing process of a well-known liquid crystal panel is utilized for the process after a bonding process, a liquid crystal display device like FIG. 1 or FIG. 2 can be obtained.
[0053]
By providing the first partition 106 a in order to maintain the alignment state of the liquid crystal inside the seal pattern 107, the contrast can be improved by reducing the alignment disorder of the liquid crystal.
[0054]
Further, by providing the second partition wall 106b, it is possible to prevent contamination of the external lead wiring portion 113 and the FPC attached thereto due to the deterioration of the seal due to moisture or the like outside the seal pattern 107. The columnar spacer 112 in addition to the first partition wall 106a and the second partition wall 106b can provide a sturdy liquid crystal display device with little variation in substrate spacing.
[0055]
Furthermore, when this liquid crystal display device is used, liquid crystal does not enter the outside of the seal pattern 107 and between the substrates, so that loss of liquid crystal can be prevented and cost reduction can be realized.
[0056]
In the cutting process, since the cutting failure is reduced, the yield is improved.
[0057]
In this embodiment mode, the first partition wall 106 a and the second partition wall 106 b are formed on both sides of the seal pattern 107 by a photolithography method. However, the first partition wall 106 a and the second partition wall 106 b may be formed only on either the inside or the outside of the seal pattern 107.
[0058]
Although an active matrix liquid crystal display device is described as an example in this embodiment mode, the present invention can also be applied to a simple matrix liquid crystal display device.
[0059]
The first partition 106a and the second partition 106b used in this embodiment can also be applied to a liquid crystal display device manufactured by a manufacturing method using a dropping injection method or a lamination method. The laminating method is a process in which a sealing material that is an ultraviolet curable resin is applied to a substrate, liquid crystal is then applied to the formed sealing pattern, and the substrate and the other substrate are sandwiched between the sealing material and the liquid crystal.
[0060]
The present invention having the above-described configuration will be described in more detail with the following examples.
[0061]
【Example】
[Example 1]
An embodiment of the present invention will be described with reference to FIGS. Here, an example is shown in which the present invention is applied to a liquid crystal display device using an active matrix substrate in which a pixel circuit and a driving circuit around the pixel circuit are provided on the same substrate. The number of pixels of the active matrix substrate is 640 × 480 pixels, and the pixel pitch is 200 μm × 200 μm.
[0062]
A first partition 106 a and a second partition 106 b are formed on the active matrix substrate 101. As shown in FIG. 2, the second partition is formed along the outer periphery of the substrate at a portion close to the outer periphery of the substrate, and is formed so as to surround the pixel portion 103, the control circuit 104, and the control circuit 111. Is a first partition wall 106b. The first partition and the second partition correspond to the inner gap material and the outer gap material, respectively. The pixel portion corresponds to a pixel region.
[0063]
Next, a plurality of columnar spacers 112 are formed in the pixel portion 103. This columnar spacer corresponds to a gap retaining material. FIG. 2 shows an example in which columnar spacers 112 are also formed in the pixel portion. Actually, the pixel portion 103 transmits pixels at a rate of one for every four pixels (2 pixels × 2 pixels). It is fabricated on the TFT so as not to block light. FIG. 5 shows an enlarged view of the pixel portion representing this state. Reference numeral 501 denotes a source wiring, 502 denotes a gate wiring, and 503 denotes a TFT.
[0064]
The first partition wall 106a, the second partition wall 106b, and the columnar spacer 112 are each patterned into a predetermined shape by photolithography. First, NN700 (manufactured by JSR) whose main component is a photosensitive acrylic material is used as a material. NN700 is applied to the entire surface of the substrate with a spinner. The film thickness is 4.2 μm. After applying NN700 and pre-baking, it is exposed with a mask aligner using an NN700 mask. Thereafter, a baking process at 250 ° C. for 1 hour is performed on the substrate which has been developed with TMAH (tetramethylammonium hydroxide) as a main component and dried. As a result, as shown in FIG. 2, a first partition 106a, a second partition 106b, and a columnar spacer 112 that are wall-shaped and surrounded by the edge of the substrate are formed. The height of the first partition 106a and the second partition 106b is 4 μm. NN700 may be applied to the entire surface of the substrate with a spinner so that the height of the columnar spacer 112 is about 3.8 μm.
[0065]
Next, an alignment film 109 containing polyimide as a main component is applied and baked on the above-described active matrix substrate 101 on which the first partition wall 106a, the second partition wall 106b, and the columnar spacer 112 are formed, and then alignment processing is performed. . The alignment film 109 uses SE5291 (Nissan Chemical). The alignment film 109 is applied on the substrate by a flexographic printing method. The thickness of the alignment film 109 is about 80 nm after baking. The alignment film is pre-baked on a hot plate at 80 ° C. and then baked in a clean oven at 250 ° C. for 1.5 hours.
[0066]
Similarly, the alignment film 109 is applied to the counter substrate 102 and baked.
[0067]
Thereafter, an alignment process is performed by rubbing. Rubbing was performed at an angle of 45 ° with respect to the active matrix substrate 101. The rubbing conditions are a roll rotation speed of 100 rpm, an indentation of 0.4 mm, and a stage speed of 10 mm / s.
[0068]
Substrate cleaning is performed after rubbing to remove dust generated in the rubbing process. Substrate cleaning was performed by immersing the substrate in IPA (isopropanol) and then drying with IPA vapor. In addition, the substrate can be cleaned using pure water.
[0069]
Next, a seal pattern 107 is formed on the substrate. For the formation of the seal pattern, screen printing or a dispenser can be used. Here, a dispenser is used. It may be applied to either one of the substrates, but in this embodiment, it is applied to the counter substrate. A thermosetting epoxy adhesive, XN-21S (Mitsui Chemicals) is used for the sealing material.
[0070]
After the sealing material is applied to the substrates, temporary baking is performed in a clean oven, and then the other substrate is prepared and the substrates are bonded together.
[0071]
Next, hot pressing is performed. This is because the sealing material is fired. A pressure is applied in advance to the pair of bonded substrates so as to crush the panel in a direction perpendicular to the substrate surface using a jig for hot pressing. The pressure at this time is 0.1 to 0.5 kgf / cm ² Here, 0.3 kg / cm ² It is. While maintaining this state, it is placed in a clean oven and the sealing material is thermally cured. Thermal curing is performed for 4 to 10 hours, here 6 hours, and the sealing material is cured.
[0072]
When the hot press is completed, the bonded substrates are cut into a predetermined shape by a general apparatus for cutting glass such as a diamond cutter. At this time, by making the dividing portion and the end of the second partition wall 106b coincide with each other, there is less division failure and the yield is improved. A dicer may be used as a general apparatus for cutting. A dicer is an apparatus that divides a substrate by rotating a hard cutter (dicing saw) at high speed.
[0073]
Liquid crystal is injected into the divided panel (the liquid crystal is not shown). The conditions of pressure control and temperature control at the time of injection differ depending on the liquid crystal, and may be performed under the optimum conditions for injecting each material. This time we will use nematic liquid crystals. Since nematic liquid crystals are fluid like liquids at room temperature, vacuum injection is performed at room temperature. The nematic liquid crystal used is ZLI4792 (manufactured by Merck Japan).
[0074]
After the liquid crystal is injected, the injection port is sealed. In this case, UV curable resin is also used for sealing. However, since the position of the injection port is considerably away from the pixel portion and after the liquid crystal is injected, the sealing material 110 enters the liquid crystal display device. Therefore, there is no particular influence on the alignment state of the liquid crystal.
[0075]
After sealing the inlet, the liquid crystal is realigned. In the realignment treatment, the manufactured liquid crystal display device is heated to 130 ° C. in a clean oven, held for 30 minutes, and then rapidly cooled to room temperature.
[0076]
In the liquid crystal display device manufactured by the method of the present invention in this manner, the sealing material is blocked by the first partition 106 a and the sealing material does not enter the pixel portion 103. On the other hand, since the liquid crystal is in contact with the first partition 106a instead of the sealing material, the alignment of the liquid crystal reflects the flatness of the side surface of the first partition 106a. The linear shape of the side surface of the first partition wall 106a is very good because it may be formed by a photolithography method. As a result, compared with the conventional liquid crystal display device in which the sealing material is in direct contact with the liquid crystal, the alignment of the liquid crystal in the liquid crystal display device of the present invention is greatly improved and the contrast is improved. Further, in addition to the first partition wall and the second partition wall, a plurality of columnar spacers 112 are formed in the pixel portion 103 in FIG. 2, so that a rugged liquid crystal display device with little variation in the gap between the substrates (gap unevenness) can be obtained. Can be provided.
[0077]
Further, by providing the second partition wall 106b, it is possible to prevent contamination of the external lead wiring portion 113 and the FPC attached thereto due to the deterioration of the seal due to moisture or the like outside the seal pattern 107.
[0078]
Furthermore, when this liquid crystal display device is used, liquid crystal does not enter the outside of the seal pattern 107 and between the substrates, so that loss of liquid crystal can be prevented and cost reduction can be realized.
[0079]
In the cutting process, since the cutting failure is reduced, the yield is improved.
[0080]
[Example 2]
In the first embodiment, the case where the first partition 106a, the second partition 106b, and the columnar spacer 112 are formed by a photolithography method has been described. However, in this embodiment, the first partition 106a and the second partition 106 are formed by a printing method. 106b is formed. 1A and 1B are a cross-sectional view and a top view of a liquid crystal display device manufactured by the method of this example.
[0081]
The active matrix substrate 101 and the counter substrate 102 used have the same configuration as that shown in the first embodiment. Further, the coating process, the rubbing process, and the post-rubbing cleaning process of the alignment film 109 are the same as those shown in the first embodiment.
[0082]
Next, a photosensitive resin is applied to the active matrix substrate 101 that has been rubbed and cleaned by flexographic printing. The photosensitive resin used here is NN700. In the printing plate, a first partition 106a and a second partition 106b are formed on a predetermined portion on a substrate, and a printing pattern is formed so as not to be formed on other portions. After coating on the substrate, NN700 is baked under the conditions as shown in Example 1. The height of the first partition 106a and the second partition 106b after firing is 3.8 μm.
[0083]
A spacer 105 for spraying is sprayed on the counter substrate 102. The spacer is made of micropearl (manufactured by Sekisui Fine Chemical) whose main component is divinylbenzene. The spacer has a diameter of 4 μm. The spacer is dry sprayed with nitrogen gas. Spray density is 100 / cm ² And
[0084]
Next, a seal material is applied to the counter substrate 102 to form a seal pattern 107. The method for applying the sealing material is the same as in Example 1. The subsequent steps are the same as those in the first embodiment.
[0085]
Through the above steps, a liquid crystal display device as shown in FIG. 1 is manufactured. By providing the first partition 106a, separation and unnecessary spread of the sealing material can be prevented as in the first embodiment.
[0086]
Further, by providing the second partition wall 106b, it is possible to prevent contamination of the external lead-out wiring portion 113 and the FPC attached thereto due to deterioration of the sealing material due to moisture or the like outside the seal pattern 107. The first partition wall 106a and the second partition wall 106b can provide a sturdy liquid crystal display device with little variation in the distance between the substrates.
[0087]
Furthermore, when this liquid crystal display device is used, liquid crystal does not enter the outside of the seal pattern 107 and between the substrates, so that loss of liquid crystal can be prevented and cost reduction can be realized.
[0088]
In the cutting process, since the cutting failure is reduced, the yield is improved.
[Example 3]
In the first embodiment and the second embodiment, the case where the liquid crystal for TN is used as the liquid crystal is shown, but in this embodiment, an example in which the ferroelectric liquid crystal is used as the liquid crystal is shown. As a method for forming the first partition wall 106a, the second partition wall 106b, and the columnar spacer 112, the method described in Embodiment 1 may be used. FIG. 2 shows a cross-sectional view and a top view of a liquid crystal display device manufactured by the method of this embodiment.
[0089]
First, as shown in Embodiment 1, the first partition 106a, the second partition 106b, and the columnar spacer 112 are formed. The NN 700 constituting them is made to have a height of 1.5 μm after firing. A columnar spacer 112 is also formed in the pixel portion 103.
[0090]
Next, an alignment film 109 is applied. The alignment film 109 is RN1286 (manufactured by Nissan Chemical), and when RN1286 (manufactured by Nissan Chemical) is used, the pretilt angle can be lowered to 1 to 3 °. The thickness of the alignment film is 10 nm to 100 nm, here 50 nm. The alignment film is formed by a flexographic printing method.
[0091]
The alignment film is pre-baked on a hot plate at 80 ° C. and then baked in a clean oven at 250 ° C. for 1.5 hours. After the alignment film is baked, a rubbing step is performed, followed by cleaning after rubbing.
[0092]
Next, a sealing material is applied to the counter substrate 102 to form a seal pattern 107. The sealing material may be a thermosetting resin. After the sealing material is temporarily fired, it is bonded to the active matrix substrate 101, and then hot pressing is performed. Hot pressing is performed in the same manner as in Example 1. The next substrate cutting step is the same as that in the first embodiment.
[0093]
Next, the liquid crystal is injected into the divided panel (the liquid crystal is not shown). The ferroelectric liquid crystal used in this embodiment is FELIX-M4850-100 (manufactured by Hoechst), but any known ferroelectric liquid crystal may be used. The characteristics of liquid crystals are that the phase series is Iso-N. ^* -SmA-SmC ^* -Cry, and the phase transition temperature is Iso-N ^* Is 76 ° C, N ^* -SmA is 71 ° C, SmA-SmC ^* Is 67 ° C, SmC ^* -Cry is -20C. At a temperature at which the liquid crystal exhibits an Iso phase, the liquid crystal is injected into the divided panel by a vacuum injection method.
[0094]
After injecting liquid crystal and sealing the inlet, realignment is performed. Here, the liquid crystal display device is heated to 100 ° C. and maintained at the temperature for 30 minutes, and then cooled to room temperature. Cooling is performed at a rate of 0.1 ° C./min.
[0095]
Since the separation of the sealing material and unnecessary spread are eliminated by the structure of the present invention, a uniform alignment state of the liquid crystal can be obtained. In addition, since the surface of the sealing material that is in contact with the liquid crystal is less likely to form alignment discontinuities, alignment defects that are particularly problematic in smectic liquid crystals are improved.
[0096]
In addition, since the columnar spacer 112 is also formed in the pixel portion 103, the uniformity of the gap and the strength against the pressure for reducing the gap can be further increased. Accordingly, in addition to the first partition wall 106a and the second partition wall 106b, a plurality of columnar spacers 112 are formed in the pixel portion 103, so that a robust liquid crystal display device with little variation in substrate spacing can be provided.
[0097]
Further, by providing the second partition wall 106b, it is possible to prevent contamination of the external lead-out wiring portion 113 and the FPC attached thereto due to deterioration of the sealing material due to moisture or the like outside the seal pattern 107.
[0098]
Furthermore, when this liquid crystal display device is used, liquid crystal does not enter the outside of the seal pattern 107 and between the substrates, so that loss of liquid crystal can be prevented and cost reduction can be realized.
[0099]
In the cutting process, since the cutting failure is reduced, the yield is improved.
[0100]
[Example 4]
A CMOS circuit and a pixel portion formed by implementing the invention of this specification can be used for various display devices (active matrix liquid crystal displays). That is, the present invention can be implemented in all electronic devices in which these display devices are incorporated in the display portion.
[0101]
Such electronic devices include video cameras, digital cameras, projectors (rear type or front type), head mounted displays (goggles type displays), car navigation systems, car stereos, personal computers, personal digital assistants (mobile computers, mobile phones) Or an electronic book). Examples of these are shown in FIGS.
[0102]
FIG. 6A illustrates a personal computer, which includes a main body 2001, an image input portion 2002, a display portion 2003, a keyboard 2004, and the like. The present invention can be applied to the image input unit 2002, the display unit 2003, and other signal control circuits.
[0103]
FIG. 6B illustrates a video camera, which includes a main body 2101, a display portion 2102, an audio input portion 2103, operation switches 2104, a battery 2105, an image receiving portion 2106, and the like. The present invention can be applied to the display portion 2102 and other signal control circuits.
[0104]
FIG. 6C illustrates a mobile computer, which includes a main body 2201, a camera unit 2202, an image receiving unit 2203, operation switches 2204, a display unit 2205, and the like. The present invention can be applied to the display portion 2205 and other signal control circuits.
[0105]
FIG. 6D shows a head-mounted display, which includes a main body 2301, a signal cable 2302, a fixed band 2303, a display monitor 2304, an optical system 2305, a display portion 2306, and the like. The present invention can be applied to the display portion 2306 and other signal control circuits.
[0106]
FIG. 6E shows a player using a recording medium (hereinafter referred to as a recording medium) on which a program is recorded, and includes a main body 2401, a display portion 2402, a speaker portion 2403, a recording medium 2404, an operation switch 2405, and the like. This player uses a DVD (Digital Versatile Disc), CD, or the like as a recording medium, and can perform music appreciation, movie appreciation, games, and the Internet. The present invention can be applied to the display portion 2402 and other signal control circuits.
[0107]
FIG. 6F illustrates a digital camera, which includes a main body 2501, a display portion 2502, an eyepiece portion 2503, an operation switch 2504, an image receiving portion (not shown), and the like. The present invention can be applied to the display portion 2502 and other signal control circuits.
[0108]
FIG. 7A illustrates a front projector, which includes a projection device 2601, a screen 2602, and the like. The present invention can be applied to a liquid crystal display device 2808, which will be described later, constituting a part of the projection device 2601 and other signal control circuits.
[0109]
FIG. 7B shows a rear projector, which includes a main body 2701, a projection device 2702, a mirror 2703, a screen 2704, and the like. The present invention can be applied to a liquid crystal display device 2808, which will be described later, constituting a part of the projection device 2702 and other signal control circuits.
[0110]
FIG. 7C is a diagram showing an example of the structure of the projection devices 2601 and 2702 in FIGS. 7A and 7B. The projection device 2601 and the projection device 2702 include a light source optical system 2801, a mirror 2802, mirrors 2804 to 2806, a dichroic mirror 2803, a prism 2807, a liquid crystal display device 2808, a phase difference plate 2809, and a projection optical system 2810. Projection optical system 2810 includes an optical system including a projection lens. Although the present embodiment shows a three-plate type example, it is not particularly limited, and for example, a single-plate type may be used. In addition, the practitioner may appropriately provide an optical system such as an optical lens, a film having a polarization function, a film for adjusting a phase difference, or an IR film in the optical path indicated by an arrow in FIG. Good.
[0111]
FIG. 7D shows an example of the structure of the light source optical system 2801 in FIG. In this embodiment, the light source optical system 2801 includes a reflector 2811, a light source 2812, a lens array 2813, a lens array 2814, a polarization conversion element 2815, and a condenser lens 2816. Note that the light source optical system illustrated in FIG. 7D is an example and is not particularly limited. For example, the practitioner may appropriately provide an optical system such as an optical lens, a film having a polarization function, a film for adjusting a phase difference, or an IR film in the light source optical system.
[0112]
However, the projector shown in FIG. 7 shows a case where a transmissive liquid crystal display device is used, and an application example in a reflective liquid crystal display device is not shown.
[0113]
FIG. 8A shows a cellular phone, which includes a main body 2901, an audio output portion 2902, an audio input portion 2903, a display portion 2904, operation switches 2905, an antenna 2906, and the like. The present invention can be applied to the audio output unit 2902, the audio input unit 2903, the display unit 2904, and other signal control circuits.
[0114]
FIG. 8B illustrates a portable book (electronic book), which includes a main body 3001, a display portion 3002, a display portion 3003, a storage medium 3004, operation switches 3005, an antenna 3006, and the like. The present invention can be applied to the display portion 3002, the display portion 3003, and other signal circuits.
[0115]
FIG. 8C illustrates a display, which includes a main body 3101, a support base 3102, a display portion 3103, and the like. The present invention can be applied to the display portion 3103. The display of the present invention is particularly advantageous when the screen is enlarged, and is advantageous for displays having a diagonal of 10 inches or more (particularly 30 inches or more).
[0116]
As described above, the application range of the present invention is extremely wide and can be applied to electronic devices in various fields. Moreover, the electronic apparatus of a present Example can be implemented even if it uses the structure which consists of what combination of Example 1- Example 3. FIG.
[0117]
【The invention's effect】
By providing the first partition in order to maintain the alignment state of the liquid crystal inside the seal pattern, the contrast can be improved by reducing the alignment disorder of the liquid crystal.
[0118]
Further, by providing the second partition wall, it is possible to prevent contamination of the external lead-out wiring portion and the FPC attached thereto due to deterioration of the sealing material due to moisture or the like outside the seal pattern.
[0119]
Further, in addition to the first partition wall 106a and the second partition wall 106b, a plurality of columnar spacers 112 are formed in the pixel portion 103, so that a rugged liquid crystal display device with little variation in the gap between the substrates (gap unevenness) can be obtained. Can be provided.
[0120]
When this liquid crystal display device is used, the liquid crystal does not enter the outside of the seal pattern and between the substrates, so that the loss of the liquid crystal can be prevented and the cost can be reduced.
[0121]
In the cutting process, since the cutting failure is reduced, the yield is improved.
[Brief description of the drawings]
FIG. 1A is a cross-sectional view of a liquid crystal display device according to the present invention taken along line AA ′.
(B) Top view of the liquid crystal display device of the present invention.
FIG. 2A is a cross-sectional view of the liquid crystal display device of the present invention taken along line AA ′.
(B) Top view of the liquid crystal display device of the present invention.
FIG. 3 shows a conventional liquid crystal display device.
FIG. 4 shows a structure of a liquid crystal display device.
FIG. 5 is an enlarged view of a pixel portion.
FIG. 6 illustrates an example of an electronic device.
FIG. 7 is a diagram showing a configuration of a projection type liquid crystal display device.
FIG. 8 is a diagram showing an example of a portable terminal.
[Explanation of symbols]
101 Active matrix substrate
102 Counter substrate
103 pixels
104 Control circuit (gate driver)
105 Spacer for spraying
106a First partition 106b Second partition
107 Seal pattern
108 Counter electrode
109 Alignment film
110 Sealing material
111 Control circuit (source driver)
112 Columnar spacer
113 External lead-out wiring section
301 Active matrix substrate
302 Counter substrate
303 pixel section
305 Spacer for spraying
307 Seal pattern
308 Counter electrode
313 Seal material separated into liquid crystal
314 Exudation of sealing material
401 Polarizing plate
402 Liquid crystal cell
403 backlight
501 Source wiring
502 Gate wiring
503 TFT

Claims (7)

A method for manufacturing a liquid crystal display device, comprising: a first substrate; a second substrate; and a liquid crystal held between a pair of substrates including the first substrate and the second substrate,
On the first substrate, a first partition is formed along the outer periphery of the first substrate,
Forming a second partition along the outer periphery of the first substrate outside the region where the first partition is formed on the first substrate;
After forming the first partition and the second partition, a seal is formed between the region where the first partition is formed and the region where the second partition is formed on the first substrate. Forming a pattern,
Bonding the first substrate and the second substrate ,
The first partition is a material having liquid crystal resistance,
The method for manufacturing a liquid crystal display device, wherein the second partition wall is a water-resistant material. In the manufacturing method of the liquid crystal display device of Claim 1 ,
A method for manufacturing a liquid crystal display device, wherein the first partition and the second partition are formed by a photolithography method. A method for manufacturing a liquid crystal display device, comprising: a first substrate; a second substrate; and a liquid crystal held between a pair of substrates including the first substrate and the second substrate,
On the first substrate, a first partition is formed by a photolithography method along the outer periphery of the first substrate,
Forming a second partition wall by a photolithography method along the outer periphery of the first substrate outside the region where the first partition wall is formed on the first substrate;
After forming the first partition and the second partition, an alignment film having polyimide or polyamide is formed in a region surrounded by the first partition on the first substrate,
After forming the alignment film, a seal pattern is formed between a region where the first partition is formed on the first substrate and a region where the second partition is formed,
Bonding the first substrate and the second substrate ,
The first partition is a material having liquid crystal resistance,
The method for manufacturing a liquid crystal display device, wherein the second partition wall is a water-resistant material. In the manufacturing method of the liquid crystal display device according to any one of claims 1 to 3 ,
A method for manufacturing a liquid crystal display device, comprising: forming a first partition; and filling a region surrounded by the first partition with the liquid crystal. In the manufacturing method of the liquid crystal display device as described in any one of Claims 1 thru | or 4 ,
The method for manufacturing a liquid crystal display device, wherein the seal pattern includes an additive. In the manufacturing method of the liquid crystal display device according to any one of claims 1 to 5 ,
The method for manufacturing a liquid crystal display device, wherein the first partition is an acrylic resin. In the manufacturing method of the liquid crystal display device according to any one of claims 1 to 6 ,
A method for manufacturing a liquid crystal display device, wherein the liquid crystal is a ferroelectric liquid crystal.

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