JP3441383B2 - Liquid crystal display device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a liquid crystal display device uniform in electrooptic characteristics by stably forming the axial symmetry orientation in whole pixel region. SOLUTION: In ASM display mode liquid crystal display device in which n-type liquid crystal material having a negative dielectric coefficient and a vertical orientation film are used. When a mixture containing the liquid crystal material and a polymerizable material is poured, pouring time is shortened or pouring speed is enhanced so as to suppress the change in the composition ratio of the materials and to adjust the voltage response time difference &Delta;&tau;of the liquid crystal material in the whole pixel region to be in the range expressed by the formula, 0 msec<&Delta;&tau;<20 msec.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a viewing angle using an n-type liquid crystal material having a negative dielectric constant, which is suitable for a large display for wall hangings, a television device for wall hangings, a car navigation, a laptop personal computer and the like. ASM (Axially Symm) with excellent characteristics
etric Aligned Micro-cell)
The present invention relates to a display mode liquid crystal display device and a manufacturing method thereof.

[0002]

2. Description of the Related Art The liquid crystal display device described above has features such as light weight, thin shape, and low power consumption. Therefore, the liquid crystal display device has been used as a key device in the coming multimedia society by various OAs (Office Automatio).
n) Liquid crystal display devices such as thin film transistors (TFTs) and PALs that have been applied and developed in the field of devices and AV (Audio Visual) devices.
C (Plasma Addressed Liquid)
A device having a crystal display) as a switching element is known.

This liquid crystal display device has a TN liquid crystal display mode in which a nematic liquid crystal molecule is twisted by about 90 ° in the vicinity of both electrode substrates when a voltage is not applied by using a horizontal alignment film in a normally white mode, and 240 ° or more. The twisting STN display mode is often used. However, in these liquid crystal display devices, the viewing angle characteristics are narrow, so that
Display performance was insufficient as an alternative display.

In order to improve the viewing angle characteristics of the liquid crystal display device, various display modes are being put into practical use. One of them is ASM as disclosed in Japanese Patent Laid-Open No. 8-341590. There is a display mode liquid crystal display device.

The operating principle of this conventional liquid crystal display device will be described with reference to FIG. In FIG. 10, (a) and (b) show the state when no voltage is applied,
(C) and (d) show the states when a voltage is applied. Also,
(A) And (c) is sectional drawing, (b) and (d) are figures which show the result of having observed the upper surface with the polarization microscope of a crossed Nicol state. The liquid crystal display device 100 has a negative dielectric anisotropy Δε (N type) between the pair of substrates 132 and 134.
A liquid crystal layer 140 composed of liquid crystal molecules 142 is sandwiched. Vertical alignment layers 138a and 138b are formed on the surfaces of the substrates 132 and 134 in contact with the liquid crystal layer 140. In addition, a convex portion 136 is formed on the surface of at least one of the pair of substrates 132 and 134 on the liquid crystal layer 140 side. Due to the convex portion 136, the liquid crystal layer 140 has two different thicknesses, dout and din. As a result, as will be described later, a liquid crystal region that exhibits an axially symmetric orientation when a voltage is applied is defined as a region surrounded by the protrusion 136. In this figure, electrodes formed on the pair of substrates 132 and 134 for applying a voltage to the liquid crystal layer 140 are omitted.

As shown in FIG. 10A, when no voltage is applied, the liquid crystal molecules 142 are aligned in the direction perpendicular to the substrate by the regulating force of the vertical alignment layers 138a and 138b. When observing a pixel region in which no voltage is applied with a crossed Nicols polarization microscope, a dark field is exhibited as shown in FIG. 10B (normally black mode). As shown in FIG. 10 (c), when a voltage is applied, the liquid crystal molecules 142 having negative dielectric anisotropy are acted on by a force that aligns the long axes of the liquid crystal molecules perpendicular to the direction of the electric field. Molecules 142 are oriented axially symmetrically about an axis 144 perpendicular to the substrate. As a result, as shown in FIG. 10D, an extinction pattern is observed in the direction along the polarization axis.

FIG. 11 shows a black display portion 11 and a white display portion 12 when the liquid crystal display device in the ASM display mode is observed under a polarizing plate parallel Nicol. This Figure 1
As shown in FIG. 1, the ASM-mode liquid crystal display device has a wide viewing angle characteristic, and is expected to be used as a substitute for a CRT or as a new application.

[0008]

In the above-described conventional liquid crystal display device, the following process is required to orient the liquid crystal molecules existing in the liquid crystal region surrounded by the polymer region in an axially symmetrical manner. Met.

First, a voltage is applied at room temperature to a precursor mixture containing a liquid crystal material and a polymerizable resin material, which are injected into the cell, so that the precursor mixture is oriented in an axially symmetrical manner. At this time, four extinction patterns are observed. Further, while applying a voltage at which these four extinction patterns were observed, the exposure energy was 0.
Irradiate with ultraviolet rays at 48 J / cm ² for 10 minutes. After this,
Even if the voltage application is stopped once and both electrodes of the pair of substrates are short-circuited outside the substrates, and the voltage is suddenly applied, the axially symmetrical orientation is maintained.

However, in the normally black mode, it takes a long time to inject the liquid crystal into the liquid crystal cell for the ASM display mode, which requires about 5 times the injection time as compared with that in the normally white mode. There's a problem.

When the precursor mixture is injected by the usual vacuum injection method, the precursor mixture moves in the gap having a cell thickness of several μm in the entire pixel region. Therefore, the composition ratio changes due to a chromatographic effect that causes friction and collision with the interface of the substrate and the projecting structure on the substrate, and the adsorption and desorption of the material constituent molecules. As a result, as shown in FIG. 12, the voltage response time τ tends to increase with the distance from the injection hole, which is considered to cause variations in electro-optical characteristics.

Further, the display quality is impaired for the same reason depending on the sectional shape, surface area, and arrangement of the cell thickness maintaining material.

The present invention has been made to solve the above-mentioned problems of the prior art, and it is possible to stably form an axially symmetric orientation in the entire pixel region, and to make the electro-optical characteristics uniform and to provide an excellent display. It is an object of the present invention to provide a liquid crystal display device having high quality and a manufacturing method thereof.

[0014]

The liquid crystal display device of the present invention comprises a liquid crystal material having a negative dielectric constant and a polymerizable resin material between a pair of substrates, at least one of which has a vertical alignment layer.
Is injected between the pair of substrates to form the polymerizable resin.
A display medium having a polymer region formed by curing an oil material and a liquid crystal region made of a liquid crystal material substantially surrounded by the polymer region is sandwiched, and liquid crystal molecules in the liquid crystal region are A liquid crystal display device that is aligned substantially perpendicular to the pair of substrates when no voltage is applied, and is axially symmetrical when a voltage is applied, and the voltage response time difference Δτ of the liquid crystal material in all pixel regions is 0 msec <Δτ ≦. 20m
It is injected between the pair of substrates so as to be in the range of sec.
Injecting time t of the mixture, the liquid crystal material and the polymerizable resin material
Relationship with the flow distance l of the mixture of materials , expressed as l ² = at
Injection coefficient a and the voltage response of the liquid crystal material in the entire pixel region.
Answer time difference Δτ is Δτ ≦ 47.3a ^-1.2 ... (1) a ≧ 2 ... (2) and Δτ ≧ 0.0003t ² + 0.015t ... (3) t ≦ 250 ... (4) is formed by injecting the mixture between the pair of substrates.
Are, above objects can be achieved.

The cell thickness holding material that defines the distance between the pair of substrates is provided in parallel with the injection path for injecting the liquid crystal material into the cell, is provided with the injection path opened, or is a point. It is desirable to be provided in place.

It is preferable that a plurality of injection holes and a plurality of exhaust holes are provided when the liquid crystal material is injected into the cell.

It is desirable to have a portion outside the pixel region where the cell thickness is thicker than other portions or thicker than inside the pixel region.

A black matrix having grooves may be provided on one of the pair of substrates. The mixture
The compound is formed between the pair of substrates by the voltage application induction injection method.
May be injected into.

In the method of manufacturing a liquid crystal display device of the present invention, a polymer region and a negative dielectric constant substantially surrounded by the polymer region are provided between a pair of substrates, at least one of which has a vertical alignment layer. A display medium having a liquid crystal region made of a liquid crystal material having a directionality is sandwiched, and liquid crystal molecules in the liquid crystal region are aligned substantially perpendicular to the pair of substrates when no voltage is applied, and are axially symmetric when a voltage is applied. A method of manufacturing a liquid crystal display device in which a liquid crystal display device is aligned in a uniform pattern, wherein a voltage response time difference Δτ of a liquid crystal material in all pixel regions is 0 msec <Δτ ≦ 20 mse.
a step of injecting a mixture containing a liquid crystal material and a polymerizable material into the cell while controlling the injection rate or the injection time so that the range is within the range of c; Comprising a step of orienting molecules in an axially symmetric manner, and a step of curing the polymerizable material to form the polymer region,
In the step of injecting the mixture into the cell, the pair of
Injection time t of the mixture injected between the substrates and flow of the mixture
Relationship with moving distance l, injection coefficient a represented by l ² = at
And the voltage response time difference Δτ of the liquid crystal material in the entire pixel area
And Δτ ≦ 47.3a ^−1.2 (1) a ≧ 2 (2) and Δτ ≧ 0.0003t ² + 0.015t (3) t ≦ 250 (4) The relationship is satisfied, and thereby the above-mentioned object is achieved.

[0020]

In the step of injecting the mixture into the cell, the voltage response time difference Δτ of the liquid crystal material in the entire pixel region is
It is desirable to perform the injection so that the injection time t and the injection time t satisfy the relationship of Δτ ≧ 0.0003t ² + 0.015t (3) t ≦ 250 (4).

It is desirable that the concentration of the polymerizable material in the liquid crystal material be 1% or less.

The step of injecting the mixture into the cell may be performed by an induction injection method.

The step of injecting the mixture into the cell may be performed by an induction pressure injection method.

The step of injecting the mixture into the cell may be performed by a voltage application induction injection method.

In this specification, the term "picture element" indicates a basic unit for forming an image in a liquid crystal display device. The term "picture element region" refers to a portion that constitutes a "picture element" in a liquid crystal display device, and this portion includes a liquid crystal region sandwiched between a pair of substrates.

In the liquid crystal display device according to the present invention, the liquid crystal regions have a fixed correspondence with the picture elements and are spatially arranged regularly. The liquid crystal region does not necessarily have to be formed for each picture element, and for example, due to manufacturing methods such as different aspect ratios, one picture element partitioned by a black matrix or the like is further divided into two or more n pieces. Then, a liquid crystal region may be formed for each divided region.

The operation of the present invention will be described below.

In the present invention, the liquid crystal molecules in the liquid crystal region are oriented in axial symmetry, so that they have excellent viewing angle characteristics.

Since the voltage response time difference Δτ of the liquid crystal material in the entire picture element region is in the range of 0 msec <Δτ ≦ 20 msec, it becomes possible to perform the ASM alignment collectively in the entire picture element region by applying the voltage, and Embodiments 1 and 2 will be described later. As shown in FIG. 3, a display quality that is not rough when viewed by human eyes is obtained. Further, there is no variation in electro-optical characteristics during voltage switching, and excellent display quality can be obtained.

In the step of injecting the mixture containing the liquid crystal material and the polymerizable material into the cell, the injection speed is increased or
Alternatively, by shortening the injection time, the liquid crystal material is injected at high speed, so that the change in the composition ratio of the mixture is suppressed.
Since the liquid crystal material is injected more uniformly, the voltage response time difference Δτ of the liquid crystal material in the entire pixel area becomes smaller.

The voltage response time difference Δτ of the liquid crystal material and the injection coefficient a in the entire picture element region have a relationship of Δτ ≦ 47.3a ^−1.2 (1) as shown in Embodiment 5 described later. When a ≧ 2 (2) is satisfied, a range of 0 msec <Δτ ≦ 20 msec is obtained, and uniform switching display quality is achieved.

The voltage response time difference Δτ of the liquid crystal material in the entire pixel region and the injection time t have a relationship of Δτ ≧ 0.0003t ² + 0.015t (3) as shown in Embodiment 5 described later. When t ≦ 250 (4), the range of 0 msec <Δτ ≦ 20 msec is obtained, and uniform switching display quality is achieved.

In order to increase the injection speed of the mixture containing the liquid crystal material and the polymerizable material, it is preferable that the viscosity coefficient of the mixture is low. Further, when the viscosity coefficient of the mixture is low, the resin concentration is uniform in the liquid crystal cell because it is less affected by the chromatographic effect with the substrate interface. Therefore, as shown in Embodiment 6 described later, it is desirable that the concentration of the polymerizable material with respect to the liquid crystal material is 1% or less, and thereby uniform switching element characteristics can be obtained.

Structural design of the liquid crystal cell is also important in order to increase the injection speed of the liquid crystal material and to shorten the injection time. Since the injection speed is proportional to the flow cross section of the liquid crystal material and inversely proportional to the flow length, it is desirable to widen the flow cross section and shorten the flow length. For this purpose, it is conceivable to increase the number of injection holes and exhaust holes, increase the cell thickness, and reduce the number of structures that act as a barrier in the injection direction. For example, the thickness or width of the black matrix is reduced to reduce the volume, or a groove or the like is provided to partially eliminate it, so that the cell thickness is thicker than the other portion outside the pixel region or inside the pixel region. By providing a thicker portion, the flow cross section becomes wider. Further, the barrier for the liquid crystal injection direction can be reduced by providing the cell thickness holding material in parallel with the injection path, opening the injection path, or providing them in a scattered manner.
The flow distance becomes shorter.

The induction injection method has a vacuum degree of 133 Pa or more 6
Since it is 700 Pa or less (1 Torr or more and 50 Torr or less), which is not so high as compared with the conventional vacuum injection method,
It is injected with almost no change in the composition ratio of the mixture.

In the induction pressure injection method, first, the injection hole and the exhaust hole are evacuated to evacuate the inside of the liquid crystal cell. Next, the mixture is immersed in the injection hole, returned to the atmosphere, and further pressurized by about 1 atm, so that the injection speed of the mixture is improved and the injection time is further shortened.

When the mixture is injected, if the long axes of the liquid crystal molecules are close to parallel to the injection direction, the flow viscosity will be lower than that in the case of being vertical, and the injection speed will be low. In the present invention,
By using a vertical alignment layer and an n-type liquid crystal material having a negative dielectric constant, the liquid crystal molecules are aligned substantially vertically when no voltage is applied and the liquid crystal molecules are aligned horizontally when a voltage is applied. It is desirable that the long axis of the is parallel to the injection direction.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

The liquid crystal display device of the present invention has basically the same configuration as the conventional liquid crystal display device 100 shown in FIG. 10, and the liquid crystal layer 140 sandwiched between the pair of substrates 132 and 134 is It has a polymer region 136 and a liquid crystal region substantially surrounded by the polymer region 136. A vertical alignment layer is formed on one or both substrates, and liquid crystal molecules in a liquid crystal region having a negative dielectric constant are aligned substantially perpendicular to the substrate when no voltage is applied, and when a voltage is applied, the liquid crystal region is aligned. Axisymmetric with respect to the central axis (perpendicular to the substrate).

The liquid crystal region of this liquid crystal display device is typically formed for each picture element defined by the opposing electrodes, and since the liquid crystal molecules in the liquid crystal region are oriented in axial symmetry, an excellent viewing angle is obtained. Have characteristics. As mentioned above,
The picture element area may include a plurality of liquid crystal areas.

In this liquid crystal display device, the voltage response time difference Δτ of the liquid crystal material in the entire pixel region is 0 msec <Δτ ≦ 2.
The range is 0 msec.

In the manufacture of this liquid crystal display device, a mixture containing a liquid crystal material and a polymerizable resin material is injected into a cell,
After applying a voltage to the mixture to orient it in an axially symmetric manner,
The polymerizable material is cured to form a liquid crystal region substantially surrounded by the polymer region.

In the step of injecting the mixture, the change in the composition ratio of the mixture is reduced in the entire pixel region, so that the voltage response time difference Δτ of the liquid crystal material in the entire pixel region can be reduced.

For example, the liquid crystal is formed in the gap 34 between the electrode substrate 39 such as a TFT substrate or a PALC substrate and the counter electrode substrate 38 such as a CF substrate by the induction injection method using the manufacturing apparatus shown in FIG. It is desirable to inject a mixture containing the material and the polymerizable material.

In this induction injection method, as shown in FIG. 1B, injection holes and exhaust holes 42, 42 are provided around the display region 43 on either one of the pair of electrode substrates. Then, as shown in FIG. 1A, the exhaust hole injection jig 31 and the injection hole injection jig 32 are arranged in the exhaust hole 35 and the injection hole 36 via the interfering silicone rubber or the O-ring 33, for example. After being evacuated for a certain period of time by a vacuum pump, the connection portion 40 of the material bottle 41 containing the mixture containing the liquid crystal material and the polymerizable material is connected to the liquid crystal material drain pipe 37 while maintaining the vacuum state, and the liquid crystal material The mixture containing the polymerizable material is injected into the cell. After the injection hole 36 is covered with the mixture, the pressure is returned to the atmospheric pressure, and the exhaust hole is directly sucked by the vacuum pump to fill the mixture in the cell.

According to this induction injection method, since the degree of vacuum is not so high as compared with the conventional vacuum injection method, it is possible to further reduce the change in the composition ratio of the mixture. At this time, when the injection hole is covered with the mixture and pressurized with nitrogen gas or the like, the induction pressure injection method is performed. Alternatively, a voltage may be applied between the pair of electrode substrates to form a voltage application induction injection method.

The present inventors measured the distance and time for a mixture containing a liquid crystal material and a polymerizable material to move in a cell,
Furthermore, regarding the liquid crystal panel for which the injection of the mixture has been completed,
The voltage application response time was measured with respect to the distance from the injection hole to calculate the response time difference. As a result, it has been found that there is a certain relationship between the required time t at which the injection is completed and the response time difference Δτ, or between the injection coefficient a and the response time difference Δτ described later. That is, the shorter the injection time or the faster the injection speed, the smaller the response time difference Δτ.

Here, the response time τ is the sum of Rise Time and Decay Time of the electro-optical characteristics of the liquid crystal material, and the response time difference Δτ is the response time measured at each part of the panel (for example, as shown in FIG. 12). It is the difference between τh and τl).

As shown in FIG. 2, when a rectangular capillary having a cross section of width w and thickness d and a length of 1 is used, and a pressure of Pa and Pb per unit area is applied to both ends to flow the liquid crystal, the unit is When the flow rate per time is Q, the viscosity coefficient η can be expressed as η = {w × d ³ (Pa−Pb)} / 12 × l × Q (5).

Since the fluctuation parameters are the injection time t and the flow distance l, the above equation (5) can be expressed as l ² = at (6).

This a is called an injection coefficient and can be obtained by regression calculation from the measurement of t and l.

Since the injection time can be shortened by increasing the unit flow rate Q in the above equation (5),
It is desirable to reduce the viscosity coefficient and the flow distance l and increase the pressure difference, the cell thickness d, and the unit cross-sectional area.

For example, it is considered effective to use the induction pressure injection method for increasing the pressure difference, and it is effective to use the voltage application induction injection method for decreasing the viscosity coefficient.

Further, in order to reduce the viscosity coefficient,
The concentration of the polymerizable material in the liquid crystal material is preferably 1% or less.

Furthermore, in order to uniformly inject the liquid crystal material composition by the chromatographic effect at the substrate interface with the cell thickness d being constant, the structural design of the liquid crystal cell is also important. For example, it is desirable to arrange the cell thickness holding material so as not to obstruct the injection direction or to design the cell so that the flow cross-sectional area becomes large.

As described above, by injecting the mixture containing the liquid crystal material and the polymerizable material in a short time, it is possible to reduce the voltage response time difference of the liquid crystal material in the entire pixel region without causing the composition ratio unevenness. You can Therefore, by applying a voltage to the mixture, it is possible to collectively perform the ASM orientation processing in all the pixel regions, and it is possible to obtain a display quality that is not rough when viewed by human eyes. Furthermore, even when voltage switching is performed, it is possible to obtain display quality without variations in electro-optical characteristics within the display area.

Hereinafter, more specific embodiments of the present invention will be described, but the present invention is not limited to these.

(Embodiment 1) In this embodiment, a liquid crystal material and a polymerizable material are formed by induction injection into a 5 type cell in which one injection hole and one exhaust hole are formed in one of a pair of substrates. The mixture containing and was injected, and the voltage response time Δτ was measured.

First, I was placed on a glass substrate having a thickness of 1.1 mm.
A sealant was patterned by screen printing on a substrate having a transparent electrode made of TO (mixture of indium oxide and tin oxide) and having a thickness of 100 nm. The glass substrate with the ITO electrode may be a TFT substrate or a PALC substrate.

On the other substrate, a transparent electrode made of ITO having a thickness of 100 nm was formed on a glass substrate having a thickness of 1.1 mm, and a thickness of 300 having an opening (a gap) of 100 μm square.
nm black matrix (B
M) was patterned. A negative-type photo-curable resin material was applied onto this substrate, exposed using a predetermined mask, and developed, rinsed and baked to form wall-shaped protrusions with a step difference of 3 μm on the BM. On the wall-shaped protrusions, a protrusion 45 having a step of 3 μm as shown in FIG. 3B was patterned in a predetermined position using a negative type photo-curable resin material. The BM, the wall-shaped projections, and the projections 45 form a projecting structure, and the portion where the liquid crystal region is formed is controlled to be a region (picture element 44) surrounded by the projecting structure.

A vertical alignment film (JAS manufactured by Japan Synthetic Rubber Co., Ltd.) was formed on the other substrate and the above-mentioned glass substrate with the ITO electrode.
LS204) was applied with a spinner and baked to form a vertical alignment layer.

Next, as shown in FIG. 1B, a hole was formed in the injection hole 42 and the exhaust hole 42 with a drill, and both substrates were bonded together to form a cell.

An n-type liquid crystal material (Δε = −4.0, Δn = 0.08, cell thickness 6 μm) was used as a liquid crystal material in this cell.
3.96 g, R684 (manufactured by Nippon Kayaku Co., Ltd.) 0.04 g as a polymerizable material, and Irugcure 6 as a photoinitiator.
41 (manufactured by Ciba Geigy) and 0.002 g were thoroughly mixed to obtain a precursor mixture. The compatibilization temperature of this precursor mixture was 80 ° C.

The precursor mixture and the cell were set in the induction injection apparatus shown in FIG. 1 (a), vacuumed for 1 hour, then poured into the injection hole and returned to normal pressure. The injection direction at this time was the direction shown by the arrow 47 in FIG. In FIG. 3A, 44 is a picture element, and 45 is a picture element.
Indicates the cell thickness holding material, and 46 and 47 indicate the injection direction of the mixture.

Injecting the precursor mixture into the cell in this way
A liquid crystal cell was produced by sealing with a photocurable sealing material. Then, by applying a voltage to the precursor mixture at room temperature, the liquid crystal molecules are oriented in an axially symmetrical manner, and while applying the axially oriented voltage, the exposure energy is 0.48 J / cm 2.
^The polymerizable material was cured by irradiating it with ultraviolet rays at ² for 10 minutes to fix the alignment of the liquid crystal.

With respect to the liquid crystal display device thus obtained, the voltage response time difference Δτ was measured at three points in the display area between the injection hole and the exhaust hole. No. Shown as 1.

[0068]

[Table 1]

The injection coefficient a at this time was 2 ≦ a ≦ 3.7, and the range of Δτ was 10 msec to 20 msec.

In this liquid crystal display device, it was possible to carry out the batch ASM orientation treatment by applying a voltage, and a display quality free of roughness was obtained. Also, in this range of Δτ,
The liquid crystal display device having no display unevenness was obtained because the response unevenness during voltage switching was not felt by human eyes.

(Embodiment 2) In Embodiment 2, a mixture containing a liquid crystal material and a polymerizable material is injected into a 5-type cell manufactured in the same manner as in Embodiment 1 by an induction pressure injection method.

The cell thickness holding material 45 was formed in a pattern as shown in FIG. 3A, and the injection direction was the direction shown by the arrow 46. After the injection step, the liquid crystal display device was manufactured in the same manner as in the first embodiment.

The results of the measurement of Δτ for this liquid crystal display device are shown in Table 1 above. Shown as 2.
With the liquid crystal display device of this embodiment, the same results as in Embodiment 1 were obtained.

In this liquid crystal display device, a batch ASM alignment treatment can be performed by applying a voltage, and a liquid crystal display device having a display quality without roughness and display unevenness during voltage switching was obtained.

(Embodiment 3) In this embodiment, (1) an injection hole 42 and an exhaust hole 42 are formed as shown in FIG.
A 5-type liquid crystal display device in which an injection path of a mixture containing a liquid crystal material and a polymerizable material is parallel to a short side direction of the liquid crystal cell, and (2) a cell structure similar to that of the first embodiment. Liquid crystal display devices of type 5 and type 25 were manufactured using plastic beads as shown in FIG. 3C instead of the thickness maintaining material.

(1) The injection path was parallel to the short side direction of the liquid crystal cell, and the injection direction was the direction shown by the arrow 47 in FIG. The same procedure as in Form 1 was performed. After the injection step, the liquid crystal display device was manufactured in the same manner as in the first embodiment.

The results of measurement of Δτ for this liquid crystal display device are shown in Table 1 above. Shown as 3.
With the liquid crystal display device of this embodiment, the same results as in Embodiment 1 were obtained.

In this liquid crystal display device, a batch ASM alignment treatment can be carried out by applying a voltage, and a liquid crystal display device having a display quality without roughness and display unevenness during voltage switching was obtained.

(2) The 5 type and 25 type liquid crystal display devices using the plastic beads 48 as shown in FIG. 3C as the cell gap material which does not become a barrier in the injection direction of the mixture are as follows. Was prepared.

First, I was put on a glass substrate having a thickness of 1.1 mm.
A sealing agent was patterned by screen printing on a substrate having a transparent electrode made of TO and having a thickness of 100 nm.

On the other substrate, a transparent electrode made of ITO having a thickness of 100 nm was formed on a glass substrate having a thickness of 1.1 mm, and a thickness of 300 having a 100 μm square opening (a gap) was formed.
nm black matrix (B
M) was patterned. On this substrate, 6 μm plastic beads (Micropearl manufactured by Sekisui Plastics Co., Ltd.) are dry-sprayed, a photocurable resin material is applied, and exposure is performed using a predetermined mask, followed by development, rinsing and baking. To form a protrusion having a height of 1.5 μm.

Subsequent steps were performed in the same manner as in Embodiment 1 to fabricate 5-type and 25-type liquid crystal display devices.

With respect to the obtained liquid crystal display devices of type 5 and 25, the measurement results of Δτ are shown in Table 1 above. 4 and No. Shown as 5.

From this result, it was found that even in the 25-inch liquid crystal display device, the range of Δτ can be set to 10 msec to 20 msec, and it can be applied to an ultra-large panel.

(Embodiment 4) In Embodiment 4, a mixture containing a liquid crystal material and a polymerizable material is injected into a 5-type cell manufactured in the same manner as in Embodiment 1 by a voltage application induction injection method.

The cell thickness holding material 45 was formed in a pattern as shown in FIG. 3 (b). The applied voltage is the saturation voltage of the transmittance (threshold voltage × 5) in the voltage transmittance characteristics shown in FIG.
Then, after the injection step, a liquid crystal display device was manufactured in the same manner as in the first embodiment.

The results of measurement of Δτ for this liquid crystal display device are shown in Table 1 above. Shown as 6.

In the liquid crystal display device of this embodiment, the injection coefficient a is 4 ≦ a ≦ 7.4 and the response time difference Δτ is 5 mse.
It was c ≦ Δτ ≦ 20 msec.

In this liquid crystal display device, the following can be considered as the reason for increasing the injection speed. In the normally black mode, an n-type liquid crystal is used in which liquid crystal molecules are aligned substantially vertically with respect to the substrate when the voltage is off and horizontally when the voltage is on. When the mixture is injected without applying a voltage, the n-type liquid crystal molecules are injected in the state perpendicular to the substrate at the interface of the vertical alignment film. In the macro state, the nematic liquid crystal molecules move in the short-axis direction and have lower lubricity than the long-axis direction, so that the injection time is longer in the vertical alignment state than in the horizontal alignment state.
Therefore, the injection time can be shortened by applying a voltage and injecting the liquid crystal molecules in a horizontal alignment state with high movement and lubricity.

In this liquid crystal display device, a batch ASM alignment treatment can be performed by applying a voltage, and a liquid crystal display device having a display quality without roughness and display unevenness during voltage switching was obtained.

(Embodiment 5) In the present embodiment, a seal pattern 49 as shown in FIG. 6 is provided in order to make the injection path of the mixture equivalent to type 20 with the size of type 5 cell. As the cell thickness holding material, the plastic beads 48 shown in FIG. 3C were used. This liquid crystal display device was manufactured in the same manner as in the first embodiment.

With respect to the liquid crystal display device thus obtained, the voltage response time difference Δτ was measured in the display region between the injection hole and the exhaust hole.

FIG. 7 shows the relationship between the injection coefficient a and the voltage response time difference Δτ, and FIG. 8 shows the injection time t and the voltage response time difference Δτ.
Shows the relationship with. Here, in the injection apparatus of FIG. 1A, the time for emptying the cell by using a vacuum pump is set to 10
The mixture containing the liquid crystal material and the polymerizable material was injected into different liquid crystal cells under different conditions from 10 minutes to 60 minutes every 10 minutes.

From FIG. 7, the relationship of Δτ≈47.3a ^−1.2 (7) was obtained.

From the above equation (7), 0 msec <Δτ ≦ 2
It can be seen that in order to satisfy the range of 0 msec, it is necessary to satisfy Δτ ≦ 47.3a ^−1.2 (1) while at the same time injecting a ≧ 2 (2).

Further, the relationship of Δτ = 0.003t ² + 0.015t (8) was obtained from FIG.

From the above equation (8), 0 msec <Δτ ≦ 2
It can be seen that in order to satisfy the range of 0 msec, Δτ ≧ 0.0003t ² + 0.015t (3) is satisfied and at the same time, t ≦ 250 (4) is injected.

The injection hole can be increased in order to shorten the injection time. In this case, however, impurities are likely to be mixed into the liquid crystal material from the encapsulating material, so that there is a concern that the retention rate may decrease, and practical application is not possible. Have difficulty.

Therefore, in order to further shorten the injection time of the mixture, the flow cross-section is made larger as the cell structure,
It is desirable to form the cell thickness holding material in a direction parallel to the injection direction, or to design it so as not to become an obstacle, and to perform it by a voltage application induction injection method or an induction pressure injection method. Also, the number of injection holes and exhaust holes can be increased.

In the case of a PALC panel, as shown in FIG. 9, a glass substrate facing the glass substrate 46 provided with plasma partition walls (ribs) 55 and plasma electrodes 57 in order to increase the liquid crystal flow cross-sectional area. CF above 50
The grooves 5 are formed in the black matrix 52 provided between the layers 51.
3 may be provided. In this case, the black matrix 52
The width 58 is about 200 μm, the groove width 59 is about 150 μm, and the plasma partition wall 55 is about 250 μm. Therefore, the groove 53 does not affect the display. In this figure, 54 is a thin glass plate of about 50 μm.

(Embodiment 6) In Embodiment 6, a 5 type cell is manufactured in the same manner as in Embodiment 1, and the concentration of the polymerizable material with respect to the liquid crystal material is changed from 0% to 5% at intervals of 0.5%. Then, each mixture was injected into different liquid crystal cells.

As a result, when the concentration of the polymerizable material with respect to the liquid crystal material is 1% or less, display unevenness does not occur,
Uniform electro-optical characteristics were obtained within the plane of the liquid crystal cell. This is because the resin concentration can be made uniform in the liquid crystal cell without being affected by the chromatographic effect with the substrate interface, and the injection rate can be made sufficiently high because the viscosity coefficient is small. Therefore, the concentration of the polymerizable material with respect to the liquid crystal material is preferably 1% or less.

Comparative Example 1 In Comparative Example 1, a mixture containing a liquid crystal material and a polymerizable material was injected into a 5-type cell manufactured in the same manner as in Embodiment 1 by a conventional vacuum injection method.

The cell thickness holding material 45 was formed in a pattern as shown in FIG. 3A, and the injection direction was the direction shown by the arrow 47. As shown in FIG. 13, a seal pattern 102 and an injection port 103 were formed in a liquid crystal cell 101, and after the injection step, a liquid crystal display device was manufactured in the same manner as in the first embodiment.

The results of measuring Δτ for this liquid crystal display device are shown in Table 1 above as sample No. Shown as 7.

In the liquid crystal display device of this comparative example, the injection coefficient a
Is 0 <a ≦ 0.5 and the response time difference Δτ is 100 ms.
It was ec or more. This is presumably because the material composition ratio of the precursor mixture changes due to the long injection time, and Δτ increases.

(Comparative Example 2) In Comparative Example 2, a mixture containing a liquid crystal material and a polymerizable material was injected into the 5-type cell manufactured in the same manner as in Embodiment 1 by the induction injection method.

The cell thickness holding material 45 was formed in a pattern as shown in FIG. 3 (a), and the injection direction was the direction shown by the arrow 46. After the injection step, the liquid crystal display device was manufactured in the same manner as in the first embodiment.

Table 1 shows the results of the measurement of Δτ for this liquid crystal display device. Shown as 8.

In the liquid crystal display device of this comparative example, the injection coefficient a
Is 0.5 ≦ a ≦ 1, and the response time difference Δτ is 50 mse
It was c ≦ Δτ ≦ 100 msec. It is considered that this is because the cell thickness holding material 45 is in the direction perpendicular to the injection direction 46, so that the injection time becomes long, the material composition ratio of the precursor mixture changes, and Δτ becomes large.

[0111]

As described above in detail, according to the present invention, the injection time of the mixture containing the liquid crystal material and the polymerizable material can be shortened in any panel size, so that all the picture elements can be obtained. A uniform composition ratio is obtained in the region, and variations in threshold characteristics do not occur. Therefore, it is possible to collectively perform the ASM orientation treatment on all the pixel regions by applying a voltage, and it is possible to obtain a high display quality without roughness.

Further, by suppressing Δτ of the mixture containing the liquid crystal material and the polymerizable material within 20 msec in the entire pixel region, a liquid crystal display excellent in display quality without electro-optical characteristics during voltage switching in the display region. The device is obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an induction injection device used in an embodiment, and a plan view showing an arrangement of injection holes and exhaust holes in a liquid crystal display device of the embodiment.

FIG. 2 is a flow model diagram of a viscous fluid.

FIG. 3 is a plan view showing a pattern of a cell thickness holding material in the embodiment.

FIG. 4 is a plan view showing the arrangement of injection holes and exhaust holes in the liquid crystal display device of Embodiment 3.

FIG. 5 is a diagram showing voltage (V) -transmittance (T) characteristics of the liquid crystal display device of Embodiment 4.

FIG. 6 shows a fifth embodiment in which the injection path of the type 5 cell is 2;
It is a top view showing a seal pattern for making it a 0 type grade.

FIG. 7 is a diagram showing a relationship between an injection coefficient of a mixture and a voltage response time difference Δτ of a liquid crystal material.

FIG. 8 is a diagram showing a relationship between an injection time of a mixture and a voltage response time difference Δτ of a liquid crystal material.

FIG. 9 is a cross-sectional view of a cell in which grooves are provided in a black matrix so that the flow cross-sectional area is increased in the PALC panel of Embodiment 5.

FIG. 10 is a cross-sectional view showing a configuration of a conventional liquid crystal display device and a plan view showing its viewing angle characteristics.

FIG. 11 is a plan view showing viewing angle characteristics in a conventional liquid crystal display device.

FIG. 12 is a diagram for explaining a voltage response time difference Δτ.

13 is a plan view showing a seal pattern and an injection port of the liquid crystal cell of Comparative Example 1. FIG.

[Explanation of symbols]

31 Exhaust hole injection jig 32 Injection jig for injection holes 33 Interfering silicone rubber or O-ring 34 Gap between a pair of substrates 35 Exhaust hole 36 injection holes 37 Liquid crystal material drain tube 38 Counter electrode substrate (CF substrate) 39 Electrode substrate (TFT substrate or PALC substrate) 40 connection 41 Material Bottle 42 Injection hole or exhaust hole 43 display area 44 picture element 45 cell thickness holding material 46, 47 Injection direction of mixture 48 cell thickness holding material (plastic beads) 49 seal pattern 50,56 glass substrate 51 CF layer 52 Black Matrix 53 Black Matrix Groove 54 50 μm thin glass plate 55 Plasma partition wall (rib) 57 Plasma electrode

Continuation of the front page (56) Reference JP-A-10-186330 (JP, A) JP-A-9-255706 (JP, A) JP-A-10-161135 (JP, A) JP-A-8-95069 (JP , A) JP 10-123571 (JP, A) JP 5-72540 (JP, A) JP 7-325293 (JP, A) JP 7-104252 (JP, A) JP 7-234412 (JP, A) JP-A-10-253974 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02F 1/1334 G02F 1/1337 G02F 1/1341

Claims (11)

(57) [Claims] 1. A liquid crystal material having a negative dielectric constant and a polymerizable material between a pair of substrates, at least one of which has a vertical alignment layer .
Injecting a mixture containing a resin material between the pair of substrates
A display medium having a polymer region formed by curing the polymerizable resin material and a liquid crystal region made of a liquid crystal material substantially surrounded by the polymer region is sandwiched, and a liquid crystal in the liquid crystal region is sandwiched. A liquid crystal display device in which molecules are aligned substantially perpendicular to the pair of substrates when no voltage is applied, and is axially symmetrical when a voltage is applied, and a voltage response time difference Δτ of the liquid crystal material in all pixel regions is 0.
msec <As the range of .DELTA..tau ≦ 20 msec, the
The injection time t of the mixture injected between the pair of substrates and the liquid crystal
Relationship with the flow distance l of the mixture of the material and the polymerizable resin material
The injection coefficient a represented by l ² = at and the total pixel area
The voltage response time difference Δτ of the liquid crystal material is Δτ ≦ 47.3a ^−1.2 (1) a ≧ 2 (2) and Δτ ≧ 0.0003t ² + 0.015t (3) t ≦ 250 (4) , the mixture is formed between the pair of substrates by injection.
It is to have, a liquid crystal display device. 2. A cell-thickness-holding material that defines a space between the pair of substrates is provided in parallel with an injection path when the liquid crystal material is injected into the cell, or is provided with an injection path opened. Alternatively, the liquid crystal display device according to claim 1, which is provided in a scattered manner. 3. The liquid crystal display device according to claim 1, wherein a plurality of injection holes and a plurality of exhaust holes are provided when the liquid crystal material is injected into the cell. 4. The liquid crystal display device according to claim 1, wherein, outside the picture element region, there is a portion where the cell thickness is thicker than other portions or thicker than inside the picture element region. 5. The liquid crystal display device according to claim 4, wherein a black matrix having a groove is provided on one of the pair of substrates. 6. The mixture is prepared by a voltage application induction injection method.
According to claim 1, which is injected between the pair of substrates.
Liquid crystal display device. 7. A liquid crystal comprising a polymer region between a pair of substrates, at least one of which has a vertical alignment layer, and a liquid crystal material having a negative dielectric anisotropy substantially surrounded by the polymer region. And a liquid crystal molecule in the liquid crystal region is aligned substantially perpendicular to the pair of substrates when no voltage is applied, and is axially symmetrical when a voltage is applied. And the voltage response time difference Δτ of the liquid crystal material in all pixel regions is 0.
A step of injecting a mixture containing a liquid crystal material and a polymerizable material into the cell while controlling the injection rate or the injection time so that msec <Δτ ≦ 20 msec, and applying a voltage to the mixture, In the step of injecting the mixture into the cell, the step of injecting the mixture into the cell includes the steps of orienting the liquid crystal molecules in the elementary regions in an axially symmetrical manner and curing the polymerizable material to form the polymer region
Injection time t of the mixture injected between the substrates and flow of the mixture
Relationship with moving distance l, injection coefficient a represented by l ² = at , and liquid crystal material in all pixel regions
Voltage response time difference Δτ of Δτ ≦ 47.3a ^−1.2 (1) a ≧ 2 (2) and Δτ ≧ 0.0003t ² + 0.015t (3) t ≦ 250 .. A method for manufacturing a liquid crystal display device , which satisfies the relationship of (4) . 8. The method for manufacturing a liquid crystal display device according to claim 7, wherein the concentration of the polymerizable material in the liquid crystal material is 1% or less. 9. Injecting the mixture into a cell,
The method for manufacturing a liquid crystal display device according to claim 7, which is performed by an induction injection method. 10. The method according to claim 7 , wherein the step of injecting the mixture into the cell is performed by an induction pressure injection method.
A method for manufacturing a liquid crystal display device according to item 1. Wherein said step of injecting into the cell the mixture, according to claim 7, wherein performing the voltage application induces implantation
Item 9. A method for manufacturing a liquid crystal display device according to any one of items 8 .