JP2000192040A - Liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display proof against the unevenness of display ascribable to the material coming into contact with the liquid crystal layer or the alignment layer. SOLUTION: This display has a color filter substrate 110 having a substrate 11, a coloring layer 24 disposed on the substrate, and electrodes arranged on the coloring layer; an opponent substrate 120 disposed in opposition to the color filter substrate; and a liquid crystal layer 70 sandwiched between the color filter substrate and the opponent substrate. In this display, the coloring layer contains organic impurities, the hydrophobicity parameter LogP of the liquid crystal molecules contained in the liquid crystal layer is 6 or above, and a liquid crystal composition containing at least 5 wt.% liquid crystal compound terminated with an -OCF3 group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art A liquid crystal display device comprises two electrode substrates each having an alignment film, with the alignment films facing each other, and sandwiching a liquid crystal layer between them. These two electrode substrates are bonded together by a sealing material and a sealing material arranged in a peripheral region, and a granular spacer or a resin formed by a photolithography method is used between them to maintain a distance between the substrates. Are arranged.

When a color display is performed by such a liquid crystal display device, a colored layer composed of red (R), green (G), and blue (B) is often arranged on one of the substrates. In some cases, a so-called active substrate having a plurality of signal lines and a plurality of scanning lines intersectingly arranged on one main surface of the substrate and a switching element arranged at each intersection is provided as a substrate facing the substrate. A matrix array substrate is used, and in some cases, a colored layer is disposed on the active matrix array substrate. Further, if necessary, a transparent protective film made of a resin may be formed on the coloring layer or the substrate having the switching elements.

[0004]

In such a liquid crystal display device, materials such as a sealing material, a sealing material, a spacer material, a protective layer material, and a coloring layer material, which are in direct contact with the liquid crystal layer or the alignment film, are used. In some cases, display unevenness and burning occurred.

[0005] The present invention has been made under such circumstances,
It is an object to provide a liquid crystal display device in which display unevenness or the like due to a material in contact with a liquid crystal layer or an alignment film is prevented.

[0006]

According to a first aspect of the present invention, there is provided a color filter having a substrate, a colored layer disposed on the substrate, and an electrode disposed on the colored layer. A substrate, a counter substrate disposed to face the color filter substrate, and a liquid crystal layer sandwiched in a gap between the color filter substrate and the counter substrate, wherein the coloring layer is an alkyl acid, a phenyl carboxylic acid, Phenylcarboxylic acid derivative, phenylenedicarboxylic acid, phenylenedicarboxylic acid derivative, alkylamine, aniline, aniline derivative, phenylenediamine, phenylenediamine derivative, phenyleneaminecarboxylic acid, phenylenediaminecarboxylic acid derivative, alkylimide, phthalimide derivative, cyanobenzene derivative, And dicyanobenzene derivatives In the liquid crystal display device containing at least one organic impurity selected et al., The molar fraction of each component i in the liquid crystal mixture contained in the liquid crystal layer and x _i,
When the hydrophobic parameter of each component i calculated using a long-chain alkyl group as a methyl group is LogP _i , x _i and Lo
Assuming that the sum of all components of the product of gP _i is LogP, LogP
Provided is a liquid crystal display device wherein P is 6 or more.

According to a second aspect of the present invention, there are provided a plurality of signal lines and a plurality of scanning lines intersecting on one principal surface of a substrate, a switching element arranged at each intersection, and the signal line. A colored layer disposed so as to cover at least a part of the scanning line and the switching element, and connected to each of the switching elements by a through hole formed in the colored layer, and on the colored layer. A liquid crystal display device comprising: an array substrate having a plurality of arranged pixel electrodes; a counter substrate disposed to face the array substrate; and a liquid crystal layer sandwiched in a gap between the array substrate and the counter substrate. the mole fraction of each component i in the liquid crystal mixture contained in the liquid crystal layer and x _i, and LogP _i hydrophobic parameter of each component i which is calculated a long chain alkyl group as a methyl group If, when the LogP the sum of all components of the product of _{x i} and LogP _i, to provide a liquid crystal display device, wherein the LogP is 6 or more.

According to the first and second aspects of the present invention, impurities contained in a seal, a sealing material, a spacer, a protective layer, and a colored layer, such as an alkyl acid, a phenyl carboxylic acid, a phenyl carboxylic acid derivative, a phenylenedicarboxylic acid, Dissolve phenylenedicarboxylic acid derivative, alkylamine, aniline, aniline derivative, phenylenediamine, phenylenediamine derivative, phenyleneamine carboxylic acid, phenyleneamine carboxylic acid derivative, alkylimide, phthalimide derivative, cyanobenzene derivative, dicyanobenzene derivative in liquid crystal layer By making it difficult to perform, it is possible to prevent white spots, uneven alignment, burning, and the like due to a decrease in the voltage holding ratio.

In the liquid crystal display device having a liquid crystal layer sandwiched between the array substrate and the counter substrate, white spots, uneven alignment, and printing are included in a seal, a sealing material, a spacer, a protective layer, a coloring layer, and the like. The above-mentioned impurities with high ionicity and polarity dissolve in the liquid crystal layer and lower the resistance value of the liquid crystal, lowering the voltage holding ratio, or re-adsorbing to the alignment film after the impurities are dissolved in the liquid crystal It is thought that it occurs by doing. Therefore, white spots, uneven alignment, and printing
This is considered to occur when there is a region where the seal, the sealing material, the spacer, the protective layer, the coloring layer, and the like are in direct contact with the liquid crystal layer or the alignment film. This includes seals, seals, spacers,
Impurities contained in the protective layer, the colored layer, etc., seep into the liquid crystal layer involved in the display area, causing elution of the impurities into the liquid crystal layer and subsequent adsorption of the impurities to the alignment film. It is presumed.

The hydrophobic parameter LogP is the logarithm of the distribution ratio P between a 1-octanol solution and an aqueous solution. Such a method using LogP is a method of calculating from empirical parameters. It is known that LogP has an extremely large number of measured values and empirical parameters, and that the measured values and the calculated values match well.

Since LogP is an equilibrium constant,
P is proportional to the difference (ΔG) in free energy per unit concentration between the octanol solution and the aqueous solution of liquid crystal molecules as shown in the following equation. ΔG = -2.3RTLogP Here, the molar component ratio of the liquid crystal molecules i and _{x i,} when the hydrophobic parameters LogP _i, the difference in free energy of the free energy and an aqueous solution of octanol solution in the entire system, As shown in the following equation, it is the sum of the free energy of each component.

ΔG _total = ΣΔG = -2.3RTLogP _i Therefore, for LogP, additivity holds, and Σx _i L
LogP of the liquid crystal mixture can be determined by setting logP _i = LogP. Table 1 below shows the molecular structure of the liquid crystal component,
The calculated values of the hydrophobic parameter LogP, the polarizability α, and the dipole moment DM are shown.

[0013]

[Table 1]

From Table 1, it can be seen that the liquid crystal component having a terminal group of --OCF ₃ is characteristic. That is, this liquid crystal component is characterized in that the polarizability α (proportional to the dielectric constant) is larger than that of the liquid crystal component having a terminal group of F, despite its large LogP and large hydrophobicity.

Usually, an attempt to increase the hydrophobicity results in a decrease in the dielectric constant in order to reduce the number of polar groups. When the dielectric constant decreases, the driving voltage increases, which is not preferable. This indicates that the liquid crystal having the terminal OCF ₃ group has high hydrophobicity, a small decrease in the retention rate, and a possibility of lowering the driving voltage.

Next, a third invention provides a color filter substrate having a substrate, a color layer disposed on the substrate, and an electrode disposed on the color layer, wherein the color filter substrate faces the color filter substrate. A disposed counter substrate, sealing means disposed on the outer periphery of the substrate except for a liquid crystal injection port for bonding the color filter substrate and the counter substrate with a predetermined gap therebetween, and a spacer for holding the gap, A liquid crystal layer made of a liquid crystal composition injected from the liquid crystal injection port into the gap, and a sealing material for sealing the liquid crystal injection port,
The coloring layer is an alkyl acid, a phenylcarboxylic acid, a phenylcarboxylic acid derivative, a phenylenedicarboxylic acid, a phenylenedicarboxylic acid derivative, an alkylamine, an aniline, an aniline derivative, a phenylenediamine, a phenylenediamine derivative, a phenyleneamine carboxylic acid, or a phenyleneamine carboxylic acid. derivatives, alkyl imide, phthalimide derivatives, cyano benzene derivatives, and in a liquid crystal display device containing at least one organic impurity selected from the group consisting of dicyanobenzene derivative, the liquid crystal composition, the molecular terminal -OCF ₃ group A liquid crystal display device comprising at least one kind of liquid crystal compound having a content of 5% by weight or more.

According to a fourth aspect of the present invention, there is provided an array substrate, a counter substrate disposed to face the array substrate, and a liquid crystal layer made of a liquid crystal composition sandwiched between the array substrate and the counter substrate. The array substrate includes a plurality of signal lines and a plurality of scanning lines arranged to intersect with one main surface;
A plurality of colored layers of different colors, which are arranged so as to cover at least a part of the switching elements, the signal lines, the scanning lines, and the switching elements, each of which is disposed on each of the intersections; A plurality of pixel electrodes connected to each of the switching elements through a through-hole portion, and disposed on the coloring layer, wherein the coloring layer includes an alkyl acid, a phenylcarboxylic acid, a phenylcarboxylic acid derivative, and phenylene. From dicarboxylic acid, phenylenedicarboxylic acid derivative, alkylamine, aniline, aniline derivative, phenylenediamine, phenylenediamine derivative, phenyleneaminecarboxylic acid, phenyleneaminecarboxylic acid derivative, and alkylimide, phthalimide derivative, cyanobenzene derivative, and dicyanobenzene derivative Group In the liquid crystal display device containing at least one organic impurity selected et al., The liquid crystal composition comprises at least one or more liquid crystal compounds having a molecular end -OCF ₃ group, the content of the liquid crystal compound is 5 wt % Of the liquid crystal display device.

According to the third and fourth aspects of the present invention, the use of a liquid crystal composition containing a liquid crystal compound having an OCF ₃ group at a molecular terminal in an amount of 5% or more can prevent image sticking and display unevenness.

According to the study by the inventors, display unevenness is caused by the fact that organic impurities in the colored layer are eluted into the liquid crystal layer and the alignment film, and as a result, display unevenness such as uneven alignment and printing phenomenon occurs. Do you get it. That is, alkyl acid, phenyl carboxylic acid, phenyl carboxylic acid derivative, phenylenedicarboxylic acid, phenylenedicarboxylic acid derivative, alkylamine, aniline, aniline derivative, phenylenediamine, phenylenediamine derivative, phenyleneamine carboxylic acid, phenyleneamine carboxylic acid derivative, alkyl Organic impurities such as imide were included in the colored layer, which was found to be the cause.

Further, it has been found that these impurities are largely contained in the green layer among the colored layers. That is, the pigment usually used for the green coloring material of the color filter of the liquid crystal display device is a chlorinated copper phthalocyanine pigment such as G7 or G36, or a chlorinated brominated copper phthalocyanine pigment. Such impurities are included in a large amount.

Further, many impurities are also contained in the dispersant for dispersing the pigment in the coloring paste. Further, it was found that the above-mentioned pigments and dispersants were decomposed at high temperatures, upon contact with alkalis, or upon exposure to ultraviolet rays, to generate the above-mentioned organic impurities. Thus, the green layer is another color,
That is, it has been found that, for example, more impurities are generated in the liquid crystal layer and the alignment film layer than in the red layer and the blue layer.

Furthermore, the present inventors have proposed a display caused by impurities eluted from a colored layer, particularly a green colored layer having a chlorinated copper phthalocyanine pigment, a chlorinated brominated copper phthalocyanine pigment, or a pigment composed of a derivative thereof. It has been found that the printing phenomenon varies greatly depending on the type of liquid crystal composition used.

This is presumably because the ability to elute the above-mentioned impurities differs depending on the chemical structure of the liquid crystal compound contained in the liquid crystal composition. The third and fourth inventions are based on such knowledge.

As the above-mentioned organic impurities, alkyl acids represented by the following formula (1), phenylcarboxylic acids or phenylcarboxylic acid derivatives represented by the following formula (2), and derivatives represented by the following formula (3) Phenylenedicarboxylic acid or phenylenedicarboxylic acid derivative, alkylamine represented by the following formula (4), aniline or aniline derivative represented by the following formula (5), phenylenediamine or phenylenediamine derivative represented by the following formula (6) A phenyleneaminecarboxylic acid or a phenyleneaminecarboxylic acid derivative represented by the following formula (7), an alkylimide represented by the following formula (8), a phthalimide derivative represented by the following formula (9), a formula (10) And a dicyanobenzene derivative represented by the following formula (11).

[0025]

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[0026]

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[0027]

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In the above formula, R ₁ is an alkyl group having 1 to 20 carbon atoms, and R ₂ is —H or 1 to 2 carbon atoms.
An alkyl group of 0, R ₃ is an alkyl group of 1 to 20 carbon atoms, V, W, X, Y, and Z are an alkyl group of 1 to 10 carbon atoms, an alkoxyl group of 1 to 10 carbon atoms, —F, —
One selected from Cl, -Br, -C ₆ H ₅ , -H,
n is 1 or 2.

The amount of the organic impurities eluted into the liquid crystal as described above is determined by placing a cured material 10 mm ³ of a coloring material containing the organic impurities and 50 cc of the liquid crystal in an ampoule tube, sealing it,
For 100 hours and then analyzed. As the liquid crystal material to be extracted, a fluorine-based liquid crystal or a cyano-based nematic liquid crystal can be used. Specifically, a cyano-based liquid crystal of ZL1-1565 (manufactured by E. Merck) or a fluorine-based liquid crystal of LOXON5001 (manufactured by Chisso) can be used. Liquid crystal was used. A Shimadzu 14A (manufactured by Shimadzu Corporation), which is a gas chromatograph, was used as the measuring instrument.

The pigments that can be used in the present invention and are contained in the colored layer include, but are not limited to, the following.

Example of green pigment

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Example of blue pigment

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Example of red pigment

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[0034]

Embodiments of the present invention will be described below. First, embodiments according to the first and second aspects of the present invention will be described. The present inventors conducted an experiment on the effect on the display characteristics of the liquid crystal cell (especially the decrease in voltage holding ratio) when various organic and inorganic substances were mixed to form a liquid crystal cell by changing the composition of the liquid crystal composition. I went like that.

In the liquid crystal cell, alignment films are applied to an array substrate having switching elements and pixel electrodes on a glass substrate, and an opposing substrate having an opposing electrode on the glass substrate. A TN structure in which a plurality of substrates are arranged and a liquid crystal layer is sandwiched between the substrates is provided. The voltage holding ratio was evaluated in a state where various organic substances and inorganic substances were deposited on the alignment film as the deposits. As a liquid crystal material, a fluorine-based liquid crystal mixture was used.

The liquid crystal cell for measuring the voltage holding ratio was manufactured as follows. First, two ITO substrates are prepared, and an alignment film material (soluble polyimide; SE) is provided on each of the substrates.
-5291: manufactured by Nissan Chemical Industries, Ltd.), heat-treated at 80 ° C. for 60 minutes, and rubbed to form an alignment film.

Dodecanoic acid is partially IP-coated on these alignment films.
10% by weight I dissolved in A (isopropyl alcohol)
Impurities were deposited by applying 1 μl of PA solution. Then, ten liquid crystal compositions were sandwiched between these two substrates, ten liquid crystal cells were assembled, and their voltage holding ratios (%) were measured. As a reference, ten liquid crystal cells were similarly prepared without attaching impurities,
The voltage holding ratio (%) was measured. The problem is the difference ΔV (%) between the voltage holding ratio (%) of the liquid crystal cell to which the impurity is attached and the liquid crystal cell to which the impurity is not attached, and it is preferable that ΔV is small.

Next, a liquid crystal cell for evaluating burn-in defects was prepared as follows. First, an array substrate and a counter substrate are prepared, and an alignment film material (soluble polyimide; SE-5291: manufactured by Nissan Chemical Industries, Ltd.) is applied on each of the substrates.
Heat treatment at 0 ° C for 60 minutes, rubbing treatment,
An alignment film was formed.

On these alignment films, 1 μl of a 10% by weight IPA solution in which dodecanoic acid was dissolved as an impurity in IPA (isopropyl alcohol) was partially applied to adhere the impurities. Then, ten kinds of liquid crystal compositions were sandwiched between these two substrates to assemble ten liquid crystal cells.

As a method of evaluating the burn-in defect, a checkerboard pattern is continuously lit for 3 hours with respect to this liquid crystal cell, and then the degree of the print unevenness of the checkerboard pattern around the impurity application region is determined by a full-scale gradation pattern. evaluated. Further, the liquid crystal cell was subjected to continuous lighting evaluation at 50 ° C. and 80% for 100 hours, and the presence or absence of display unevenness was evaluated by a reliability test.

Chemical calculation of the hydrophobic parameter LogP of liquid crystal molecules was performed using a HyperChem (manufactured by Hypercube) and a personal computer (PV3000:
(Manufactured by Toshiba Corporation). First, molecular force field calculation (MM +)
Is used to calculate the optimal conformation of the liquid crystal molecules,
The empirical QSAR (Quantitat)
live Structure-Activity Re
The hydrophobicity parameter, LogP, was calculated using the L. program. Liquid crystal molecules are mixtures of various molecules, but all alkyl groups were calculated as methyl groups. This is because a common alkyl group is not important for considering the relative difference between liquid crystals.

In Table 2 below, various liquid crystal mixtures having different LogP values (LC1-LC1) prepared by combining and mixing liquid crystals having various liquid crystal molecular structures shown in Table 1 above.
0) LogP, Δ of liquid crystal cell determined as described above
V indicates the presence or absence of white spot defect and printing defect.

[0043]

[Table 2]

From Table 2, it can be seen that 10 ⁷ / P and ΔV are almost directly proportional. In order for ΔV to be 10% or less, 10 ⁷ / P is 10 or less, that is, LogP is 6 or less.
It is understood that the above is sufficient. It is known from another experiment using a TFT array substrate that white defects do not occur when ΔV is 10% or less. More preferably, when LogP is 6.3 or more, ΔV is 5% or less, and the reliability of the liquid crystal display device is further improved.

1 / P is the distribution ratio of liquid crystal molecules [LC] aq /
[LC] octanol and [LC] aq >> [LC] octan
Since it is ol, 1 / P is almost proportional to [LC] aq.
[LC] aq is considered to indicate the magnitude of the interaction between liquid crystal and water (polar substance). Therefore, as 1 / P is larger, polar impurities are more likely to be contained, and ΔV becomes larger.

FIG. 1 is a sectional view showing the liquid crystal display device according to the above embodiment. As shown in FIG. 1, the liquid crystal display device 10 includes a counter substrate 120 and a color filter substrate 110.
The liquid crystal layer 70 is sandwiched between the two substrates, and the distance between these two substrates is held by the granular spacer 31.
The opposing substrate 120 and the color filter substrate 110 are provided with a seal 25 disposed so as to surround the outer periphery of the substrate except for the liquid crystal injection port.
The sealing material is applied to the liquid crystal injection port 32. As a sealing material, a thermosetting epoxy adhesive ES-5500 (manufactured by Mitsui Toatsu Chemicals, Inc.) was used.

The opposing substrate 120 is formed on the transparent substrate 21 by IT.
The transparent electrode 22 made of O and the alignment film 13 are sequentially arranged. Further, as shown in FIG. 2, the color filter substrate (array substrate) 110 includes a transparent substrate 11 on which a scanning line (not shown) made of MoW (molybdenum / tungsten) and a gate electrode 16 are arranged. The gate insulating film 12 made of silicon oxide and silicon nitride is arranged so as to cover the gate electrode 16.

On the gate insulating film 12, a semiconductor layer 15 made of amorphous silicon is arranged.
A source electrode 20, a drain electrode 18, and a signal line (not shown) having a three-layer structure of 1 / Mo are arranged. The signal lines and the scanning lines are arranged so as to intersect with each other, and a switching element 14 including a gate electrode 16, a gate insulating film 12, a semiconductor layer 15, a source electrode 20, and a drain electrode 18 is connected to each intersection, and is connected to the switching element. Pixel electrode 30
Is arranged.

Then, the red coloring layer (R) 24a and the green coloring layer (G) 24 cover the switching element 14.
b, blue colored layers (B) 24c are arranged in a stripe pattern. The pixel electrode 30 is disposed on the colored layer 24 and has a through hole 26 formed in the colored layer 24.
Is connected to the source electrode 20 via the. Further, an alignment film 13 is disposed on the entire surface of the substrate so as to cover the pixel electrode 30 and the coloring layer 24.

As the coloring layer material, ultraviolet curable acrylic resins CK-2000, CG2000, CR-200
0, CB-2000 (manufactured by Fuji Hunt Technology Co., Ltd.) and polyimide SE-5294 as an alignment film material.
(Manufactured by Nissan Chemical Industries, Ltd.).

Next, the manufacturing process of the liquid crystal display device described above will be described. First, the color filter substrate 110
Will be described. On the transparent substrate 11, a molybdenum-tungsten film having a thickness of about 0.3 μm was deposited by a sputtering method and patterned to form the gate electrode 16 and the scanning line. Next, an amorphous silicon film was deposited by a CVD method, and the amorphous silicon film was patterned to form a semiconductor layer 15 of the TFT.

Next, Mo (molybdenum), Al (aluminum), and Mo (molybdenum) were sequentially deposited and patterned to form a signal line, a source electrode 20, and a drain electrode 18.

Thereafter, an ultraviolet curable acrylic green resist solution (CGY-S624D) was spin-coated on the substrate on which the electrodes were formed. Subsequently, at about 90 ° C. for about 5
Pre-baked for 1 minute, and
Exposure was performed with ultraviolet light having an intensity of 50 mJ / cm ² . The photomask pattern used here has a stripe-shaped pattern corresponding to the green colored layer and a through hole 26 for connecting the pixel electrode 30 and the source electrode 12 with a diameter of 1.
It has a 5 μm circular pattern.

Subsequently, using an aqueous solution of about 0.1% by weight of TMAH (tetramethylammonium hydride),
Develop the green resist film for about 60 seconds, wash it with water,
By performing post-baking at about 200 ° C. for about 1 hour, a green colored layer 24 a having a through hole 26 was formed.

Subsequently, the blue coloring layer 24b and the red coloring layer 2
4c was formed by the same process as that for the green coloring layer 24a. Next, indium tin oxide (ITO) is deposited on the coloring layer 24 by a sputtering method, and the pixel electrode 30 is formed by patterning the indium tin oxide (ITO). An alignment film material made of polyimide is applied to the entire surface of the substrate. The alignment film was formed by performing the treatment, and the color filter substrate 110 was obtained.

Next, ITO is deposited to a thickness of about 100 nm on the transparent substrate 21 by a sputtering method to form a counter electrode 22. Subsequently, an alignment film material made of polyimide is applied to the entire surface of the substrate, and alignment processing is performed. To form an alignment film,
A counter substrate 120 was obtained.

Then, on the alignment film surface of the counter substrate 120,
Granular spacers 31 having a diameter of about 5 μm were sprayed at a rate of about 100 per square mm. Subsequently, as shown in FIG. 3, a sealing material 25 mixed with a fiber having a predetermined size was applied to the periphery of the opposing substrate 120 except for an injection port 32 for injecting liquid crystal. The opposing substrate 120 and the color filter substrate 110 are attached to each other with the sealant 25 to complete an empty cell.

Next, a nematic liquid crystal material to which a chiral material is added (one of the liquid crystal mixtures LC1 to LC10 having different LogP values shown in Table 2 above) is vacuum-injected into the liquid crystal cell from the injection port 32, and injected. Thereafter, the injection port 32 is sealed using an ultraviolet curable resin as the sealing material 33, and then a polarizing plate (not shown) is disposed on each side of the cell, thereby completing the liquid crystal display device.

As described above, different Logs are used.
A life test was performed on a liquid crystal display device manufactured by injecting a liquid crystal mixture having P. That is, an image was displayed at 80 ° C., and the time required for the occurrence of whiteout failure and the time required for the occurrence of burn-in failure were measured. The results are shown in Table 3 below. The measurement was performed up to 1000 hours, and “not generated” in the table means that no measurement was generated after 1000 hours.

[0060]

[Table 3]

From Table 3 above, it can be seen that all the liquid crystal display devices using the liquid crystal mixture having a Log P of 6 or more have a practical durability of 300 hours or more.

Next, embodiments according to the third and fourth aspects of the present invention will be described. First, the results of experiments performed by the inventors will be described. First, SE-749228 (manufactured by Nissan Chemical Industries, Ltd.) is applied as an alignment film to a thickness of 80 nm on two glass substrates each having an ITO electrode of 1 cm 2, baked, rubbed, and sealed around the both. To form an empty cell, and in this cell, as a liquid crystal composition, -OCF ₃ was added at the molecular end.
Liquid crystal compounds A and B having a group, and -O
Liquid crystal compounds C, D, E, F, G having no CF ₃ group
Various liquid crystal compositions in which H and I were mixed at various concentrations were prepared, and a mixture obtained by adding 3% by weight of a green copper phthalocyanine pigment was injected into the liquid crystal compositions to prepare a liquid crystal cell for voltage holding ratio measurement.

For this liquid crystal cell, the frame frequency 1
The effective value of the voltage held when a 6.6 ms gate pulse was applied was calculated and defined as the voltage holding ratio. Measurement temperature is 60 ° C
Met. The results are shown in Table 4 below.

Further, various liquid crystal compositions to which the green copper phthalocyanine pigment was not added were injected into a liquid crystal display device as shown in FIG. 1 using an active matrix substrate on which a color filter was actually formed, and burn-in. 70 ° C, 8
The display unevenness after performing the 0% operation for 300 hours was evaluated.
The results are also shown in Tables 4 and 5 below.

The UV curable acrylic resin CRY-S623C (red) containing a red pigment (pigment red) used as a coloring layer material, and the CGY-S containing a green pigment (pigment green 7, pigment green 3b).
624D (green), blue pigment (pigment blue 16)
The elution amount of CBV-S625C (blue) (manufactured by Fuji Film Ohlin Co., Ltd.) into the liquid crystal composition containing is 500 ppm, 30 ppm, and 10 ppm, respectively.

[0066]

[Table 4]

[0067]

[Table 5]

The liquid crystal compound used is as shown in the following formula. A: R-X-X-Y-OCF ₃ B: R-X-X-C ₂ H ₄ -Y-OCF ₃ C: R-X-X-Y-F ₂ D: R-X-Y-Y _{-F 2 E: R-X-} X-Y-F 3 F: R-X-Y-Y-F3 G: R-X-X- C 2 H 4 -Y-F 3 H: R-X-X -F.

In the formula, R is an alkyl group having 1 to 8 carbon atoms, X is cyclohexane, Y is benzene, and -F ₂ is 2
-F ₃ is replaced by three F atoms
Indicates that it is substituted with an atom. In addition, although not described in Table 4, actually, 0.5 wt% of S-811 (manufactured by Merck Japan) as a chiral material in the liquid crystal composition.
Each of the liquid crystal display devices was evaluated by adding each of them, injecting them into each cell, and evaluating each liquid crystal display device.

As is apparent from Tables 4 and 5,
When a liquid crystal composition containing less than 5% of a liquid crystal compound having an OCF ₃ group at a molecular terminal is used, the voltage holding ratio when G7 or G36 is added is remarkably reduced, and image sticking or display unevenness is caused. On the other hand, when a liquid crystal composition containing 5% or more of a liquid crystal compound having a —OCF ₃ group at a molecular terminal is used, there is almost no decrease in voltage holding ratio when G7 or G36 is added, and It can be seen that no actual burn-in or display unevenness has occurred.

As described above, in the embodiments according to the third and fourth aspects of the present invention, the use of a liquid crystal composition containing 5% or more of a liquid crystal compound having a —OCF ₃ group at a molecular terminal causes burn-in. And display unevenness can be effectively prevented.

In the case of a liquid crystal display device in which a color filter substrate having a colored layer and an active matrix array substrate are installed facing each other, the electrodes on the color filter substrate usually cover the entire colored layer in many cases. If necessary, the orientation of liquid crystal molecules may be controlled by an electric field generated by a hole provided in the electrode of the color filter substrate corresponding to the display electrode on the opposing array substrate. Alternatively, it is provided as needed and comes into contact with the liquid crystal layer via the alignment film. In such a case, the present invention is particularly effective.

Further, a colored layer is provided on the array substrate,
In the case where the coloring layer is arranged so as to cover at least a part of the signal line, the scanning line, and the switching element, and the switching element and the pixel electrode are connected by a through hole formed in the coloring layer, the coloring layer is protected. When no layer is provided, the colored layer is inevitably exposed from the pixel electrode. In this case, the present invention is particularly effective.

Next, another example of the third and fourth embodiments of the present invention will be described with reference to FIG.

In the above-mentioned liquid crystal display device, the switching element is an inverted staggered type and amorphous silicon is used as a semiconductor layer. In this example, the switching element is a positive staggered type and polysilicon is used as a semiconductor layer. ing. In the above example, a spherical spacer is used as the spacer, whereas in the present example, a columnar spacer fixed to one substrate is used. In this embodiment, a black resin mixed with red, green, and blue pigments is used as the spacer.

As shown in FIG. 4, the liquid crystal display 100
Has a liquid crystal layer 70 interposed between a counter substrate 120 and a color filter substrate (array substrate) 310, and the distance between these two substrates is held by, for example, a columnar spacer 219.

The counter substrate 120 is configured by sequentially arranging a counter electrode 22 and an alignment film 13 on a transparent substrate 21. On the other hand, a color filter substrate (array substrate) 310
Is a method in which an undercoating layer 211 having a two-layer structure of a silicon oxide film and a silicon nitride film is disposed on a transparent substrate 210, and a semiconductor active layer (channel region) 214 and a high concentration Impurity regions 213 are arranged, a gate oxide film 212 is formed so as to cover them, and a gate electrode 215 is arranged on the gate oxide film 212 to form a positive staggered polysilicon TFT.

Note that a scanning line (not shown) is formed in the same step as the gate electrode 215. A signal line 219 having a two-layer structure of Mo and Al is arranged on the scanning line and the gate oxide film 212. The signal line 219 is connected to the high-concentration impurity region 213 via a first contact hole 221 penetrating the interlayer insulating film 220 and the gate oxide film 212.

On the signal line 219, an inorganic insulating film 216 having a two-layer structure of a silicon oxide film and a silicon nitride film,
A colored layer 217 made of an organic resin having a thickness of 3 μm and having a stripe shape of three colors of blue and green is provided. As the organic resin, an ultraviolet-curable acrylic resin CK-2000 (trade name: manufactured by Fuji Film Ourin Co., Ltd.) was used.

A second contact hole 222 is formed in the inorganic insulating film 216 and the coloring layer 217.
On the coloring layer 217, the above-described columnar spacer 230 for maintaining a distance between the array substrate 310 and the counter substrate 120 is disposed in a region where a pixel electrode is not formed later. When forming the columnar spacer 230, a frame light-shielding layer was simultaneously formed in a frame shape along the outer periphery of the substrate.

On the colored layer 217, a pixel electrode 218 made of ITO is arranged.
It is electrically connected to the signal line 219. Further, an alignment film 13 is provided so as to cover the columnar spacer 219, the pixel electrode 218, and the coloring layer 217.

The liquid crystal display device configured as described above is
The liquid crystal composition of (1) shown in Table 4 above containing 20 wt% of a liquid crystal compound having a —OCF ₃ group at the molecular terminal was used, and therefore, display unevenness such as uneven alignment and image sticking was not observed.

In the above example, the color filters are arranged on the array substrate side on which the switching elements are arranged. However, it is needless to say that the present invention can be applied to the case where the color filters are arranged on the opposing substrate. The electrode on the opposing substrate has an opening, and can be applied with a very large effect when the coloring layer is in contact with the liquid crystal layer via the alignment film, or when the coloring layer is directly in contact with the liquid crystal layer. .

[0084]

As described above in detail, according to the first and second aspects of the present invention, the hydrophobic parameter Lo of the liquid crystal molecules is Lo.
By using a liquid crystal mixture having a gP of 6 or more, impurities contained in a seal, a sealing material, a spacer, a protective layer, a coloring layer, and the like can be hardly dissolved in the liquid crystal layer, thereby lowering the voltage holding ratio. White spots, uneven alignment, baking, etc. can be effectively prevented.

According to the third and fourth aspects of the present invention, by using a liquid crystal composition containing 5 wt% or more of a liquid crystal compound having a —OCF ₃ group at a molecular terminal, a display caused by impurities eluted from a colored layer is obtained. Irregularity and burning can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a color filter substrate of the liquid crystal display device according to one embodiment of the present invention.

FIG. 3 is a schematic plan view showing a coating position of a sealing material and a sealing material of the liquid crystal display device according to one embodiment of the present invention.

FIG. 4 is a longitudinal sectional view showing a liquid crystal display device according to another embodiment of the present invention.

[Explanation of symbols]

 10, 100 liquid crystal display device 11, 21, 210 substrate 12 gate insulating film 13 alignment film 14 switching element 15 semiconductor layer 16 gate electrode 18 drain electrode 20 source electrode 21 substrate 22 counter electrode Reference Signs List 24 colored layer 26 through hole 30 pixel electrode 31 spacer 70 liquid crystal layer 110 color filter substrate 120 counter substrate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Jin Hato 1-9-2 Hara-cho, Fukaya-shi, Saitama Pref. Inside the Toshiba Fukaya Electronics Factory (72) Inventor Natsuko Maya 1-9-9 Harara-cho, Fukaya-shi, Saitama No. 2 Inside Toshiba Fukaya Electronics Factory (72) Inventor Atsushi Manabe 1-9-2 Harara-cho, Fukaya-shi, Saitama Prefecture Inside Toshiba Fukaya Electronics Factory (72) Inventor Kiyoshi Shobara 1 Harara-cho, Fukaya-shi, Saitama No. 9-2, Toshiba Fukaya Electronics Factory (72) Inventor Daisuke Miyazaki 1-9-2, Hara-cho, Fukaya-shi, Saitama Prefecture Toshiba Fukaya Electronics Factory (72) Inventor Soji Akiyoshi Shara, Fukaya-shi, Saitama 1-9-2, Tochiba F-term in Toshiba Fukaya Electronics Factory (reference) 2H048 BA45 BB02 BB14 BB44 2H091 FA02Y FB02 FB12 FB13 GA00 GA06 GA13 4H027 BA02 B C04 BD24 BE02 CQ04 CR03 CR04 CT03 CT04 CW04

Claims (6)

[Claims] A color filter substrate having a substrate, a color layer disposed on the substrate, and an electrode disposed on the color layer; a counter substrate disposed to face the color filter substrate; Comprising a liquid crystal layer sandwiched in the gap between the color filter substrate and the counter substrate, the coloring layer, alkyl acid, phenylcarboxylic acid, phenylcarboxylic acid derivative, phenylenedicarboxylic acid, phenylenedicarboxylic acid derivative, alkylamine, Aniline, aniline derivatives,
Liquid crystal display containing at least one organic impurity selected from the group consisting of phenylenediamine, phenylenediamine derivative, phenyleneamine carboxylic acid, phenyleneamine carboxylic acid derivative, alkylimide, phthalimide derivative, cyanobenzene derivative, and dicyanobenzene derivative In the apparatus, when the molar fraction of each component i of the liquid crystal mixture contained in the liquid crystal layer is x _i, and the hydrophobic parameter of each component i calculated with a long-chain alkyl group as a methyl group is LogP _i , x The sum of all components of the product of _i and LogP _i is LogP
Wherein the LogP is 6 or more. 2. A plurality of signal lines and a plurality of scanning lines intersectingly arranged on one principal surface of a substrate, switching elements arranged at each intersection, the signal lines, the scanning lines, and the scanning lines. A colored layer disposed to cover at least a part of the switching element, and a plurality of pixels connected to each of the switching elements by through-hole portions formed in the colored layer and disposed on the colored layer A liquid crystal display device comprising: an array substrate having electrodes; a counter substrate disposed to face the array substrate; and a liquid crystal layer sandwiched in a gap between the array substrate and the counter substrate. If the mole fraction of each component i in the liquid crystal mixtures and x _i, and the hydrophobicity parameters of each component i which is calculated a long chain alkyl group as a methyl group and LogP _i, x _i and L LogP the sum of all components of the product of gP _i
Wherein the LogP is 6 or more. 3. A color filter substrate having a substrate, a color layer disposed on the substrate, and an electrode disposed on the color layer, a counter substrate disposed to face the color filter substrate, Sealing means arranged around the outer periphery of the substrate except for a liquid crystal injection port for adhering the color filter substrate and the counter substrate with a predetermined gap therebetween, a spacer for holding the gap, and the gap from the liquid crystal injection port A liquid crystal layer comprising a liquid crystal composition injected into the liquid crystal layer, and a sealing material for sealing the liquid crystal injection port, the coloring layer, alkyl acid, phenylcarboxylic acid, phenylcarboxylic acid derivative, phenylenedicarboxylic acid, Phenylenedicarboxylic acid derivative, alkylamine, aniline, aniline derivative, phenylenediamine, phenylenediamine derivative, phenyleneamine cal Bonic acid, phenyleneamine carboxylic acid derivative, alkyl imide, phthalimide derivative, cyanobenzene derivative,
And at least one organic impurity selected from the group consisting of a dicyanobenzene derivative and the liquid crystal composition, wherein the liquid crystal composition comprises at least one liquid crystal compound having a molecular terminal —OCF ₃ group, A liquid crystal display device having a compound content of 5% by weight or more. 4. The liquid crystal display device according to claim 1, wherein a switching element is disposed on one of the color filter substrate and the counter substrate. 5. An array substrate comprising: an array substrate; a counter substrate disposed to face the array substrate; and a liquid crystal layer made of a liquid crystal composition sandwiched between the array substrate and the counter substrate. A plurality of signal lines and a plurality of scanning lines intersecting on one main surface, a switching element arranged for each intersection, and at least a part of the signal line, the scanning line and the switching element A plurality of colored layers of different colors arranged so as to cover the plurality of pixel electrodes arranged on the colored layers connected to each of the switching elements through through-hole portions formed in the colored layers. Wherein the colored layer comprises an alkyl acid, a phenylcarboxylic acid, a phenylcarboxylic acid derivative, a phenylenedicarboxylic acid, a phenylenedicarboxylic acid derivative, an alkylamine, Phosphorus, aniline derivatives, phenylene diamine, phenylene diamine derivatives, phenylene amine carboxylic acid, phenylene amine carboxylic acid derivative and alkyl imides,
Phthalimide derivatives, cyano benzene derivatives, and in a liquid crystal display device containing at least one organic impurity selected from the group consisting of dicyanobenzene derivative, said liquid crystal composition comprises at least a liquid crystal compound having a molecular terminal -OCF ₃ group A liquid crystal display device comprising at least one kind, wherein the content of the liquid crystal compound is 5% by weight or more. 6. The coloring layer contains at least one selected from the group consisting of chlorinated copper phthalocyanine pigments, chlorinated brominated copper phthalocyanine pigments, and homologous pigments thereof. The liquid crystal display device according to claim 3.