JP2006243502A - Forming method for spacer for liquid crystal display element, and liquid crystal display element with spacer formed by the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forming method for a spacer for a liquid crystal display element in which a desired spacer can be formed on a light shield region on a substrate without causing clogging of an ink jet head. <P>SOLUTION: The volume of resin ink for spacer formation jetted by an ink jet method is set large enough to make an ink droplet project from the light shield region. Then an ink droplet is formed which is fine enough to be put in the light shield region by greatly shrinking the volume of the ink droplet through a drying stage for the resin ink. Further, a region which is smaller in contact angle than a circumference is provided in a portion in the light shield region to suppress the movement of the ink droplet in the drying stage. Then drying conditions are controlled to adjust the height of the spacer, thereby forming a desired spacer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for forming a spacer for a liquid crystal display element and a liquid crystal display element having a spacer formed by this method, and more particularly, a method for forming a spacer, which is a constituent member of a liquid crystal display element, using an inkjet method. And a liquid crystal display device provided with a spacer formed by this method.

In recent years, liquid crystal display elements are widely used in various electronic devices such as personal computers, televisions, electronic notebooks, and mobile phones.
In general, a liquid crystal display element has a liquid crystal layer made of a liquid crystal composition sandwiched between two insulating substrates made of a transparent glass substrate or the like so as to face each other. The liquid crystal layer is configured to be sealed by a sealing member that bonds the portions together.
Usually, a liquid crystal driving element such as a TFT (Thin Film Transistor) is formed on one of the two insulating substrates, and a color filter is formed on the other substrate facing each other.

If there is a gap between the two insulating substrates (hereinafter referred to as “cell gap”), that is, if the thickness of the liquid crystal layer is uneven, liquid crystal display unevenness may occur. It is necessary to hold it accurately and uniformly.
In order to uniformly maintain a narrow cell gap of about 2 to 5 μm, for example, plastic beads having a substantially uniform diameter are dispersed on a substrate by spraying, and these plastic beads are used as so-called spacers for maintaining the cell gap. There is.

  However, since plastic beads serving as spacers are randomly dispersed in the seal member and it is difficult to control the dispersion, the density of the spacer distribution locally occurs. In particular, if a large number of spacers aggregate in an area that transmits light from a light source and is used for display (hereinafter referred to as “translucent area”), liquid crystal display unevenness due to light leakage occurs, resulting in display quality. There is a problem that decreases.

  On the other hand, a method of selectively forming a spacer only in a region that does not transmit light (hereinafter referred to as a “light-shielding region”) such as a region where a black matrix exists has been proposed. If the spacer can be arranged in the light-shielding region, liquid crystal display unevenness caused by the spacer can be suppressed, so that a liquid crystal display element with good display quality can be provided.

As a method of selectively forming the spacer in the light shielding region as described above, a method of forming a spacer made of a photoresist in the light shielding region using photolithography can be given. There has also been proposed a method in which a curable resin composition is selectively ejected to a light shielding region by an ink jet method, and the ejected resin composition is cured to form a spacer (Patent Document 1 and Patent Document 2).
JP 2001-83525 A Since the inkjet method does not require a mask for forming a spacer in a desired region, it is expected that the spacer can be formed at a lower cost than the photolithography method.

However, when a technique for forming a spacer by discharging a curable resin composition using an ink jet method is put to practical use, the following problems occur.
In the ink jet method, the volume of ink droplets ejected at a time is usually approximately 1 picoliter (pl) or more, and 4 to 5 pl or more is required to ensure a stable ejection operation. The reason is related to the nozzle diameter at the tip of the discharge nozzle portion in the ink jet method, and it is necessary to reduce the nozzle diameter in order to reduce the discharge volume of ink droplets, but if the nozzle diameter is too small, the nozzle This is because clogging of ink tends to occur near the portion.

On the other hand, it is desirable that the ejection volume of ink droplets for selectively forming spacers in the light shielding region is 1 pl or less.
For example, normally, a black matrix as a light shielding region has a width of about 25 μm, and a case where a spacer having a height of 3.5 μm is formed is considered here. If an ink droplet having a circular bottom surface and a diameter of 25 μm can be formed with a height of 3.5 μm (assuming that the surface of the ink droplet can be approximated by a spherical surface), its volume is 0.88 pl. From this, it can be seen that the volume of the spacer formed is smaller than the volume of the ink droplet that can stably be ejected practically by the ink jet method.

  Furthermore, in the ink jet method, the landing position where the ejected ink droplets adhere to the substrate often deviates slightly from the desired position. The reason for this is due to factors related to the inkjet head, such as the shape of the nozzle part and the non-uniformity of the reforming process on the surface of the nozzle part, and disturbance factors in which the ejected ink droplets are affected by wind during flight. Things can be considered. Therefore, it is usually necessary to estimate a deviation of the landing position of about ± 5 μm.

  In order to further improve the accuracy of the landing position, it is necessary to adopt a device configuration that thoroughly eliminates disturbance factors such as wind, and to select and use a head with good landing position accuracy from among the manufactured inkjet heads. I don't get it. For this reason, the new problem that the manufacturing cost of an inkjet apparatus rises generate | occur | produces.

  Therefore, it is understood that the diameter of the circular bottom surface of the spacer should be about 15 μm or less considering that the accuracy of the landing position is ± 5 μm and ink droplets are ejected into the light shielding region. If calculation similar to the above is performed, the spacer volume at this time is calculated as 0.33 pl. The volume of the spacer is required to be approximately 0.4 to 0.5 pl or less, although there are some changes depending on the height of the spacer, the area of the light shielding area (black matrix area, etc.), and the landing position accuracy. It can be seen that a very small volume spacer should be formed.

  That is, when the curable resin composition is ejected as droplets in the ink jet method, there is a problem that the ink jet head is clogged if the ink droplet ejection volume is made smaller depending on the volume of the spacer to be formed. On the other hand, there is a problem that if the ink droplet discharge volume is increased so that the ink jet head can be stably discharged, the formed spacer protrudes from the light shielding region and causes light leakage.

  Therefore, in consideration of the accuracy of the landing position in the ink jet method, it is a very big problem to form a desired spacer in the light shielding region without causing clogging of the ink jet head.

  In response to this problem, the present inventor has found that the resin ink protrudes from the light shielding region to the light transmitting region at the time when the droplet of the spacer forming resin ink containing the curable resin composition and the solvent has landed on the substrate in the inkjet method. It is sufficient that the cured resin ink is disposed as a spacer in the light shielding region at the time of curing, and at least the solvent and the resin composition are evaporated in the resin ink drying process. The inventors have found that the volume of the resin ink can be reduced with good controllability, and have completed the present invention.

  That is, according to one aspect of the present invention, a discharge step of discharging a spacer forming resin ink containing a curable resin composition and a solvent in a part of a light-shielding region formed on a transparent substrate by an inkjet method, and a discharge A drying process for drying the resin ink, and a curing process for curing the resin ink after the drying process to form a spacer. The resin ink is ejected in such a size that the droplets protrude from the light shielding area in the ejection process. There is provided a method for forming a spacer for a liquid crystal display element, wherein the droplet is contracted to a size that fits in the light shielding region in the curing step.

  Here, examples of the curable resin composition to be used include a thermosetting resin and an ultraviolet curable resin. Examples of the solvent include carbitol, butyl carbitol, methyl carbitol, carbitol acetate, butyl carbitol acetate, and the like.

  According to another aspect of the present invention, a liquid crystal layer is sandwiched between a pair of opposed transparent substrates, and the spacer is formed on one substrate by the spacer forming method according to claim 1. A liquid crystal display element is provided, in which the gap between the pair of substrates is held by the spacer.

According to one aspect of the present invention, since the amount of ejected resin ink droplets may be relatively large, it is possible to reduce the probability of malfunction such as non-ejection and form a spacer with a desired volume. It becomes possible. Further, by evaporating the solvent and the resin composition itself in the drying step, the volume of the resin ink remaining after the drying step can be reduced, so that a desired minute volume spacer can be formed.
According to another aspect of the present invention, a highly reliable liquid crystal display element including a spacer having a desired volume can be obtained.

In the present invention, the volume (discharge amount) of the resin ink to be discharged is preferably at least 10 times the volume of the spacer to be formed.
The reason for this is that, as described above, the volume of the spacer is approximately 1 pl or less, and if the landing position accuracy is also taken into consideration, it is a very small volume of about 0.5 pl or less. This is because it has been proved by experiments that if the volume of the spacer formed after drying / curing is 10 times or more, the occurrence of problems such as clogging of the inkjet head can be suppressed and the spacer can be stably formed.

In the present invention, before the ejection step, ink showing liquid repellency with respect to the resin ink (for example, diluting an alkyl fluoride resin with an organic solvent) in a predetermined area including the area to which the ejected resin ink adheres. It is preferable to include a step of applying ink.
In this way, the contact angle of the ejected resin ink droplets can be made larger than the surroundings, so that the bottom area of the ink droplets can be reduced compared to when no special treatment is performed. It becomes. As a result, it is possible to form a spacer having a small volume by reducing the bottom area of the ink droplet while maintaining a predetermined height.

In general, the height of the spacer allows only an error of about 0.1 μm or less. If the wettability of the substrate surface to the resin ink is not uniform, the shape of the ink droplet changes, and as a result, the height of the cured ink droplet may deviate from the desired height.
According to this forming method, since the ink showing liquid repellency with respect to the resin ink is applied to the substrate before the discharging step, there is an effect of making the surface of the substrate uniform regardless of the history of the previous steps, Variation in the height of the spacer can be reduced.

  Further, in the present invention, prior to the ejection step, there is a step of forming a specific region in which the ejected resin ink adheres within the light shielding region and the contact angle of the resin ink is smaller than the surroundings. Is preferred. As a method for forming such a specific region, for example, the alkyl fluoride resin is applied to a color filter substrate on which an ITO electrode is formed, and the fluorination of the region to be the specific region is performed by a laser cutting process using a laser cutter. There is a method of removing the alkyl resin.

In the present invention, when a minute volume spacer is formed by evaporating a solvent or the like, the resin ink having a circular bottom shape does not necessarily contract concentrically in the drying process, and the center position moves before and after the drying process. Often to do. Therefore, a specific area in which the contact angle of the resin ink is smaller than the surrounding area is provided in advance in the light shielding area.
As a result, the interface energy between the discharged resin ink and the substrate surface becomes higher in this specific area, so if the resin ink gets wet on the specific area, the energy is lower than when the resin ink gets wet in areas other than the specific area. A state can be realized. Therefore, in the process of drying the resin ink, the ink droplets are dried while receiving an action that exists on the specific area, and are pinned and dried on the specific area in the light shielding area. It becomes.

  In the present invention, the area of the specific region formed in the light shielding region is preferably set smaller than the bottom area of the spacer formed after the curing step. This is because if the specific region having a smaller contact angle is larger than the bottom area of the spacer, it is difficult to form a spacer having a higher height.

  Based on the Cassie contact angle equation, the contact angle formed by the ink droplets decreases as the proportion of the region with a small contact angle on the bottom surface of the ink droplets increases. It is desirable to limit the area of the region having a small contact angle to such an extent that an effect of suppressing movement is recognized.

In the present invention, it is preferable that at least a part of the specific region formed in the light shielding region is formed near the edge in the light shielding region.
If the drying process of the ink droplet is examined in detail, it can be seen that the pinning effect does not appear in a state where a region having a smaller contact angle exists at the center of the bottom surface of the ink droplet. In this state, even if the area is reduced in any direction when the bottom area of the ink droplet is reduced, the bottom surface of the ink droplet still includes the specific region.
On the other hand, if the specific region exists so as to be in contact with the outer peripheral portion of the bottom surface of the ink droplet, the bottom area of the ink droplet is reduced while including the specific region, so that the pinning effect is manifested. Will be.

  Then, by forming the specific area closer to the edge than the center of the light shielding area, it is possible to prevent the outer peripheral part of the ink droplet from moving further from the edge of the light shielding area toward the center. As a result, the central portion of the ink droplet can be stopped near the central portion of the light shielding region. For example, when the light shielding region exists in a band shape, it can be said that it is more desirable to form one or more specific regions at positions near both edges.

  In the present invention, the drying step is preferably a step of heat-treating the resin ink and controlling the volume of the spacer formed by at least one of a heating temperature and a heating time during the heat-treatment.

When the spacer forming resin ink containing the curable resin composition and the solvent is dried and cured in accordance with the present invention, the volume of the spacer formed is a mixture of the solvent and the resin component for curing. It is not determined only by the ratio, but the volume changes depending on the heating temperature and heating time during the heat treatment.
Further, the role that the spacer should originally play is to maintain a desired height. However, when the resin ink for forming the spacer is discharged and cured by the ink jet method as in the present invention, the substrate and the resin ink Since the shape changes in relation to the surface properties such as wettability, a spacer having a desired height may not always be formed even if the volume is controlled to a predetermined amount.

  According to the present invention, a spacer having a desired height can be formed by changing the heating temperature and / or the heating time during the drying process without changing the solvent content ratio in the resin ink. It is not necessary to select a resin ink composition for forming a spacer suitable for the method and to sequentially determine optimum discharge conditions for the selected resin ink.

  Embodiments of the present invention will be described below with reference to the drawings. However, this embodiment is illustrative in all respects and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

[Embodiment 1]
Hereinafter, a process of forming a spacer based on Embodiment 1 on a glass substrate on which a color filter is formed (hereinafter, “color filter substrate 1”) will be described with reference to FIGS.
FIG. 1 is an enlarged plan view of the color filter substrate 1 as viewed from above. A transparent electrode, an alignment film, and the like may be formed on the color filter substrate 1, but these are omitted in FIG.

Each picture element region 2 is arranged in a matrix pattern shape, and a black matrix region 3 as a light shielding region is formed in the gap. R, G, and B shown in FIG. 1 indicate that the respective picture elements are red, green, and blue.
The size and pitch of the picture element region 2 are set in accordance with the target display performance of the liquid crystal display element, and the pitch is about 50 to 500 μm.

  The black matrix region 3 has a line width of approximately 20 to 30 μm, and in the present embodiment, a spacer forming resin ink is ejected by an ink jet method to form a spacer on the black matrix region 3.

The inkjet ink ejection method uses, for example, a piezoelectric material typified by PZT (lead zirconate titanate), changes the volume of the ink chamber by the distortion of the piezoelectric material, and ejects the ink from the nozzle by a dynamic action. The piezo method can be mentioned. Alternatively, a heat conversion method may be employed in which air bubbles are instantaneously generated by energizing and heating a heater disposed in the nozzle, and ink is ejected by the pressure. Any method can be used as long as it can eject a minute amount of ink, and the method is not particularly limited.
The drive frequency for ejecting ink is not particularly limited, but if it is set to 1 kHz to 100 kHz, preferably 10 kHz to 30 kHz, ink droplets can be ejected satisfactorily.

  As described above, if the ink droplet discharge amount is set to about 1 pl by narrowing the nozzle diameter or the like, the possibility of non-discharge increases, so it is desirable to set it to about 4 to 5 pl or more. However, when the discharge amount becomes extremely large, the time required for the drying process becomes long. Further, since the degree to which the center position of the ink droplet moves during the drying process is increased, it is difficult to form a spacer in the light shielding region. From the above, the ink droplet discharge amount is preferably about 100 pl or less, more preferably about 10 pl or less.

  The distance from the nozzle tip surface to the color filter substrate 1 is preferably set to about 500 μm. If this distance becomes longer, the accuracy of the ink droplet landing position tends to decrease. Moreover, if it becomes shorter, there is a high possibility that the nozzle tip and the color filter substrate 1 come into contact with each other.

  Furthermore, the ink droplet ejection speed may be set to 5 to 10 m / sec when ink is ejected from the nozzle. If this discharge speed is made slower, the influence of air resistance becomes stronger and the landing accuracy tends to be lowered. Further, if the ejection speed is made faster, the ink droplets will rebound when they land on the substrate 1, and there is a possibility that the ink will scatter outside the desired area.

As described above, if the driving frequency, the distance from the nozzle tip to the TFT substrate, and the ink droplet ejection speed are set to the above-mentioned conditions, suitable ink ejection is possible. However, the conditions particularly limit the present invention. It can be set as appropriate in consideration of desired conditions.
Such conditions are set as appropriate, and as shown in FIG. 2, spacer forming resin ink containing a solvent for spacer formation is discharged from the inkjet head 4 onto the color filter substrate 1.

Considering that the resin ink to be ejected is 4 pl or more and the accuracy of the landing position of the resin ink in the ink jet method is about ± 5 μm as described above, all the ink liquid ejected to form the spacers It is difficult to store the droplets in the black matrix region 3 immediately after being discharged onto the substrate 1.
Actually, as shown in FIG. 2, the ejected ink droplet 5 is formed so as to protrude from the black matrix region 3 having a width of 20 to 30 μm.

Next, the ink droplet 5 is dried by a drying process. That is, the volume of the ink droplet 5 is reduced by evaporating the solvent and the resin composition. In this step, it is only necessary to evaporate the solvent, but depending on the drying conditions, it is also possible to evaporate the resin composition for the purpose of curing. That is, the volume after drying can be controlled by the drying conditions.
Further, if the content ratio of the solvent is increased, the volume of the ink droplet 5 can be reduced relatively easily, and the ink droplet 5 can be contained in the black matrix region 3 as shown in FIG. It becomes possible.

  And if the process which hardens a resin composition is performed after the said drying process, a spacer can be formed on the black matrix area | region 3 which is a light shielding area | region.

  FIG. 4 shows the relationship between the ink droplets 5 and the black matrix region 3 when the black matrix region 3 of the color filter substrate 1 is enlarged and viewed from above. FIG. 4A shows a state immediately after the ink droplets 5 are formed by discharging the resin ink from the inkjet head 4. Here, the ink droplet 5 has a relatively large volume, and the ink droplet 5 protrudes from the black matrix region 3 to the picture element region 2. Then, by the drying process, the volume of the ink droplet 5 contracts and decreases as shown in FIG. 4B, and the bottom surface of the ink droplet 5 is accommodated in the black matrix region 3. Next, a desired spacer can be formed by performing a process of curing the resin composition of the ink droplet 5.

  The resin ink for spacer formation used here contains a solvent whose main purpose is to evaporate in the drying step and a curable resin composition whose main purpose is to form a spacer by curing by a curing process.

The solvent is not particularly limited, but in the ink jet method, if the solvent evaporates on the nozzle surface of the ink jet head 4, it causes non-ejection (clogging), and the composition of the solvent and the curable resin composition varies. Therefore, it is desirable to select an organic solvent having a low vapor pressure at a temperature (for example, room temperature) at which the inkjet head 4 operates. Examples of such a solvent include carbitol, butyl carbitol, methyl carbitol, carbitol acetate, butyl carbitol acetate, and the like.
The curable resin composition is not particularly limited, and examples thereof include a thermosetting resin and an ultraviolet curable resin.

  The resin ink for forming a spacer containing a solvent and a curable resin composition needs to be able to be ejected by an inkjet method, and the viscosity is adjusted to, for example, 2 to 50 centipoise (cP), preferably about 5 to 30 cP. Should. If the viscosity is too high, the ink for forming the spacer cannot be ejected from the inkjet head 4. On the other hand, if the viscosity is too low, the spacer forming ink is sprayed and many fine droplets are ejected, making it difficult to form the intended ink droplet 5.

  As described above, according to the present embodiment, the resin ink is ejected at an ink ejection amount that enables stable operation in the inkjet method, specifically, an ink ejection amount of 4 to 5 pl or more, and the light shielding region. Ink droplets 5 having a minute volume are formed by evaporating the solvent or the solvent and the curable resin composition while forming the bottom surface of the ink droplets 5 substantially protruding from the black matrix region 3. It is possible to store the bottom surface of the ink droplet 5 after being formed and cured in the black matrix region 3.

  In the present embodiment, an example is shown in which the ink droplets 5 are formed on the black matrix region 3 that is the light shielding region formed on the color filter substrate 1, and the spacer is formed. It is not limited to three. For example, the wiring region for electrically connecting the liquid crystal driving element etc. on the substrate side on which the liquid crystal driving element is formed is also a light shielding region, so a spacer is formed on the wiring region of the substrate on which the liquid crystal driving element is formed. You may do it.

  By the way, before the step of discharging the resin ink, in order to make the contact angle of the resin ink in a predetermined area including the area where the resin ink is discharged larger than the surrounding area, an ink having liquid repellency with respect to the resin ink is used. If it is applied to the substrate, the bottom area of the ink droplet 5 after ejection is reduced, and it becomes easy to store the ink droplet 5 in the black matrix region 3.

  In general, the wettability of the substrate surface may change over time due to causes such as organic contamination. When the spacer is formed by curing the ink droplet 5 as in the present invention, the wettability of the substrate surface is related to the contact angle of the ink droplet 5, and as a result, the height of the spacer is affected by the wettability. . Therefore, in order to form a good-quality spacer and produce a high-quality liquid crystal display element, it is necessary to set the surface wettability constant in the entire region where the spacer is to be formed on the substrate.

  As described above, performing the surface treatment on a wide range of predetermined regions including the region where the resin ink is discharged before the step of discharging the resin ink by the inkjet head 4 also has an effect of maintaining the surface wettability constant. Have.

  In addition, as a method for applying the liquid repellency ink to the substrate, an ink jet method may be used, but a spin coating method may be used in some cases.

As the ink exhibiting liquid repellency, an organic solvent containing a small amount (for example, about 1 to 5%) of a fluorine resin, for example, a fluoroalkyl resin may be used. And if an organic solvent is volatilized after application | coating, a fluoroalkyl resin will remain in a thin film shape. As a result, the bottom area of the ink droplets formed by the spacer forming resin ink can be reduced.
In addition, since the thickness of the alkyl fluoride resin layer remaining in a thin film shape exhibits sufficient liquid repellency even when the thickness is 0.05 μm, it is desirable that the alkyl fluoride resin is sufficiently diluted. If the thickness of the alkyl fluoride resin layer becomes extremely thick, an error in the thickness cannot be ignored as an error in the spacer height.

  Here, it will be explained by experimental results that the volume of the resin ink containing the solvent is sufficiently reduced.

The resin ink for forming the spacer is a resin ink in which an equal amount of an ultraviolet curable ink (Dainippon Ink, model name: SD-2407) as a curable resin composition and butyl carbitol acetate as a solvent are mixed. The resin ink was discharged onto a glass substrate using a piezo inkjet head 4 to prepare a sample.
The single ejection amount from the used inkjet head 4 is about 5 pl. This is because the mass of ink droplets when 30,000 droplets of ink are ejected is measured with an electronic balance, and is converted from a resin ink density to a droplet volume of 30,000 droplets. Is the calculated discharge amount.

For this sample, the substrate 1 was heated to dry the ink droplets 5. At this time, the ink droplets 5 were cured by variously changing the drying conditions and then irradiated with an ultraviolet lamp (illuminance 200 mW / cm ² ) having a wavelength peak at 365 nm for 120 seconds. Then, the shape of the ink droplet 5 after the curing treatment was observed with a laser microscope, and its volume was calculated.
Table 1 shows the heating temperature and drying time of the substrate 1 at the time of drying, and the volume of the ink droplets 5 after the completion of curing.

As shown in Table 1, although 5 pl of resin ink was ejected, the size of the ink droplet 5 cured through the drying process and the curing process was 0.5 pl or less, 0.1 times the ejection amount. The following minute ink droplets 5, that is, spacers can be formed.
Further, even when the resin ink has the same amount of solvent (butyl carbitol acetate), the volume of the ink droplet 5 after curing varies depending on the heating temperature and the heating time. Therefore, it can be determined that the volume of the ink droplet 5 can be controlled by the heating temperature and the heating time during drying.

  Thus, being able to control the volume of the ink droplets 5 by the heating temperature and heating time during drying means that the spacer height can be adjusted. The spacer height can also be adjusted by adjusting the mixing ratio between the solvent in the resin ink and the curable resin composition. However, if it is found that the spacer height slightly deviates from the desired region in the production process of the liquid crystal display element, the resin ink supplied to the inkjet head is replaced in order to adjust the resin ink composition as described above. Therefore, it is necessary to perform a complicated procedure for confirming that the resin ink can be normally ejected by the ink jet 4 or obtaining an optimum ejection condition.

Changing the drying conditions as described above is a simple response method compared to replacing the resin ink, and can be said to be an effective control method in the production process of the liquid crystal display element.
That is, after the step of forming the spacer, a step of monitoring the spacer height (or spacer volume) is added, and when the spacer height is out of the allowable range, the result is fed back and the ink in the spacer forming step is fed back. It is also possible to change and adjust the drying conditions of the droplets 5 to return the spacer height to within the allowable range.

[Embodiment 2]
The second embodiment is different from the first embodiment in that a specific region 6 having a smaller contact angle than the surroundings is formed in the black matrix region 3 which is a light shielding region. Since the types of the color filter substrate 1, the ink jet head 4, and the spacer forming resin ink for forming the spacer are the same as those in the first embodiment, the description thereof is omitted. Only the procedure for forming the spacer will be described below with reference to FIGS.

FIG. 5A shows the color filter substrate 1 in which a specific area 6 in which the contact angle of the resin ink is smaller than that of the surrounding area is formed in part of the black matrix area 3.
A spacer forming resin ink is discharged onto the color filter substrate 1 by an ink jet method. Since the ejection amount is relatively large, the formed ink droplet 5 is in a state of protruding from the black matrix (the bottom peripheral portion 7 of the bottom surface of the ink droplet 5 is indicated by a dotted line in FIG. 5B).

  Next, FIG. 5C shows a situation in which the volume of the ink droplet 5 decreases (the bottom area of the ink droplet 5 decreases) by drying the ink droplet 5. Here, an example is shown in which the center position of the ink droplet 5 moves in the lower right direction of the drawing relative to the ejection point, and the arrow in the drawing indicates the direction in which the bottom peripheral portion 7 of the ink droplet 5 moves. Yes.

  Assuming that the regions other than the intentionally formed specific region 6 exhibit uniform surface properties throughout the entire area, the resin ink and the substrate are used regardless of the specific direction of the center of the ink droplet 5 that is moved by the drying process. Since there is no difference in the interfacial energy from 1, the ink droplet 5 can easily move in that particular direction.

However, as shown in FIG. 5D, when the drying progresses and the outer peripheral portion 7 of the bottom surface of the ink droplet 5 comes into contact with the specific region 6 having a smaller contact angle, thereafter, the ink droplet is placed on the specific region 6. The action of decreasing the volume while leaving 5 works. Thereby, the center of the ink droplet 5 is in the upper left direction as shown in FIG. 5D, that is, in the direction opposite to the direction in which the center of the ink droplet 5 is moved in FIG. 6 so that the ink droplet 5 is pinned to 6.
As a result, as shown in FIG. 5 (e), it is possible to suppress the movement of the center of the ink droplet 5 from the black matrix region 3 and to keep the ink droplet 5 in the black matrix region 3. Become.

  In FIG. 5A, one specific region 6 is formed near the center of the width of the band-shaped black matrix region 3. However, as shown in FIG. You may form one by one.

  6A, immediately after the resin ink is ejected and the ink droplet 5 is formed, the bottom peripheral portion 7 of the ink droplet 5 is the black matrix region 3 as in FIG. 5B. (FIG. 6B). However, if the bottom peripheral portion 7 of the ink droplet 5 moves from the pixel region 2 into the black matrix region 3 (FIG. 6C), the pinning effect as described above appears immediately. And as shown in FIG.6 (d), it can suppress that the ink droplet 5 moves outside the black matrix area | region 3 by the two specific area | regions 6 where a contact angle becomes smaller, and can complete | finish a drying process. it can.

  6A to 6D, the bottom surface of the ink droplet 5 can be arranged on the black matrix 3, and the bottom surface width is close to the width of the black matrix region 3. Since the ink droplet 5 can be formed, the volume reduction amount of the ink droplet 5 can be made relatively low.

  In addition, as a formation method of the specific area | region 6 in which a contact angle becomes smaller than the circumference | surroundings, the following method is mentioned, for example.

  First, it is assumed that the surface of the color filter substrate 1 has a relatively small contact angle of the ejected spacer forming resin ink (for example, the contact angle is about 20 ° or less). For example, the contact angle of the surface of the color filter substrate 1 is sufficiently small when an ITO thin film that is a transparent electrode is formed.

  An ink obtained by diluting a fluorine-based resin (fluorinated alkyl resin or the like) with an organic solvent is applied to the color filter substrate 1 by an inkjet method. Thereafter, by volatilizing the organic solvent, a fluorine-based resin layer remaining in a thin film is formed in the application region, and the surface of the region becomes liquid repellent. Next, the fluororesin in the region that should be the specific region 6 is removed by a laser cutting process using a laser cutter.

  The specific region 6 formed by the above process returns to the state of the surface of the substrate 1 before applying the ink in which the fluororesin is diluted with an organic solvent, and the fluororesin is removed by the laser cutting process. In the surrounding area where there was no liquid repellency, the contact angle is smaller than the surrounding area.

  For example, an ITO thin film is formed on the surface of a spacer forming resin ink formed by mixing butyl carbitol acetate and ultraviolet curable ink (Dainippon Ink Co., Ltd., model name SD-2407) in equal amounts. When dropped on the surface of the substrate 1, the contact angle formed by the ink droplet 5 was 2 °. In contrast, when the resin ink was dropped onto the surface of the substrate 1 where the alkyl fluoride resin layer remained with a thickness of 30 nm, the contact angle of the ink droplet 5 was 70 °.

  Therefore, if the fluoroalkyl resin is applied to the color filter substrate 1 on which the ITO electrode is formed, and the fluoroalkyl resin in a specific region is removed by laser cutting with a laser cutter, the contact angle is sufficiently small. It can be seen that can be formed.

  As is clear from the above description, the “specific region in which the contact angle is smaller than the surroundings” means that the contact angle when the ink droplet 5 is formed only in the region is the contact angle in a region other than the region It means a region that becomes smaller than that.

Moreover, the said pinning effect becomes large, so that the area of the specific area | region 6 whose contact angle becomes smaller than the periphery is large. However, as the area of the specific region 6 increases in the bottom region of the ink droplet 5, the contact angle of the ink droplet 6 decreases.
Therefore, it is desirable to keep the area of the specific region 6 at an area where the pinning effect appears to the extent that the ink droplet 5 does not move.

In Embodiment 1 of this invention, it is a figure for demonstrating the structure of the color filter substrate which forms a spacer. In Embodiment 1 of this invention, it is a figure for demonstrating apply | coating the resin ink for forming a spacer on a color filter substrate by the inkjet method. FIG. 3 is a diagram for explaining that by drying ink droplets based on the resin ink ejected in FIG. 2, the volume of the ink droplets is reduced and the bottom surface of the ink droplets is stored in a black matrix region. FIG. 4 is a plan view of the state of FIGS. 2 and 3 as viewed from above the color filter substrate, illustrating the relationship between the bottom surface of the ink droplet and the black matrix region. In Embodiment 2 of the present invention, a configuration in which a region where the contact angle is smaller than the surroundings is arranged in the black matrix region, which is a light shielding region, and in this configuration, the contact angle is set in the step of drying ink droplets. It is a figure explaining that the area | region smaller than this suppresses a movement of an ink droplet. In Embodiment 2 of this invention, it is a figure which shows the structure which forms the area | region where a contact angle becomes smaller than the circumference | surroundings near the edge part of a black matrix, Furthermore, in this structure, it is an ink droplet which has a comparatively large volume Even so, it is a diagram illustrating that ink droplets can be stored on a black matrix.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Color filter board | substrate 2 Picture element area | region 3 Black matrix area | region 4 Inkjet head 5 Ink droplet 6 Area | region where a contact angle becomes smaller than the periphery 7 Bottom surface outer peripheral part of an ink droplet

Claims (8)

A discharging step of discharging a spacer forming resin ink containing a curable resin composition and a solvent in a part of a light shielding region formed on a transparent substrate by an inkjet method, a drying step of drying the discharged resin ink, and drying A curing step of curing the resin ink after the step to form a spacer,
The resin ink is ejected in such a size that the droplets protrude from the light shielding region in the ejection process, and is contracted to a size that allows the droplets to fit in the light shielding region in the curing step. Method.   The method for forming a spacer according to claim 1, wherein the volume of the resin ink ejected in the ejection step is at least 10 times the volume of the spacer to be formed.   The spacer according to claim 1, further comprising a step of applying an ink exhibiting liquid repellency to the resin ink in a predetermined region including a region to which the discharged resin ink adheres before the discharging step. Forming method.   4. The method according to claim 1, further comprising a step of forming a specific region in which the ejected resin ink adheres within the light-shielding region and the contact angle of the resin ink is smaller than the surroundings before the ejecting step. A method for forming a spacer according to claim 1.   The method for forming a spacer according to claim 4, wherein an area of the specific region is set smaller than a bottom area of the spacer to be formed.   The method for forming a spacer according to claim 4, wherein at least a part of the specific region is formed near the edge in the light shielding region.   A drying process consists of heat-processing resin ink, and is a process of controlling the volume of the spacer formed by at least one of the heating temperature at the time of the heat processing, and heating time. The formation method of the spacer of description. A liquid crystal layer is sandwiched between a pair of opposing transparent substrates, a spacer is formed on one substrate by the spacer forming method according to claim 1, and a gap between the pair of substrates is the same. A liquid crystal display element which is held by a spacer.

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