JPH1096897A - Liquid crystal element, its production and liquid crystal display device having this liquid crystal element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate display unevenness based on temp. distribution within a liquid crystal element plane. SOLUTION: Liquid crystals 15 exhibiting a chiral smectic phase are held between a pair of substrates 11a and 11b which respectively have electrodes 12a, 12b and are disposed to face each other apart a gap of a prescribed length. This element has at least a section connected with a driving circuit 40 for supplying voltage for liquid crystal driving to the electrodes 12a, 12b. The gap is made smaller as the distance from at least one side of the sides connected with this driving circuit 40 increases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device in which liquid crystal is sandwiched between substrates having electrodes, and more particularly to a liquid crystal device configuration for preventing display unevenness due to heat generated by driving.

[0002]

2. Description of the Related Art Clark and Lagerwall have proposed a display device of a type in which a transmitted light is controlled in combination with a polarizing plate by utilizing the refractive index anisotropy of ferroelectric liquid crystal molecules. (JP-A-56-107216). This ferroelectric liquid crystal generally has a chiral smectic phase in a specific temperature range, and in this state, in response to an applied electric field, one of the first optical stable state and the second optical stable state And has a property of maintaining the state when no electric field is applied, that is, it has bistability, and has a quick response to a change in the electric field, and is expected to be widely used as a high-speed and storage-type display element. .

[0003]

However, in order for the above-mentioned chiral smectic liquid crystal to cancel the helical arrangement of molecules inherently present and to have bistability, a cell gap (between a pair of substrates in a liquid crystal cell structure) is required. It is necessary to reduce the length of the gap (effective distance). In addition, it is necessary to uniformly reduce the cell gap in order to eliminate coloring caused by the relationship between the birefringence of the liquid crystal and the cell gap. When the cell gap is reduced, the distance between the transparent electrodes is reduced, so that the capacitance of the liquid crystal element is increased. Therefore, when an element having a structure in which a chiral smectic liquid crystal is sandwiched between a pair of substrates (between electrode substrates) is driven, heat generated by a driving IC provided on an edge of the element increases.
The heat generated causes a temperature distribution in the liquid crystal element surface, and accordingly, the driving characteristics (for example, threshold characteristics) of the liquid crystal molecules become non-uniform, causing display unevenness and deteriorating display quality. Was.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object thereof is to solve a problem in a liquid crystal element, particularly in a liquid crystal panel surface due to heat generation near a portion where a driving IC or the like is mounted. An object of the present invention is to eliminate an excessively uneven temperature distribution and prevent display unevenness in a plane. In particular, it is an object of the present invention to provide a liquid crystal element having a small cell gap, such as a liquid crystal element using a chiral smectic liquid crystal, which solves the above problems.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to provide a liquid crystal device having electrodes each having at least one liquid crystal exhibiting a chiral smectic phase sandwiched between a pair of substrates facing each other with a predetermined gap therebetween. A liquid crystal element having a portion to which a driving circuit for supplying a voltage for driving liquid crystal to the electrode is connected to the side, and as a distance from at least one of the sides to which the driving circuit is connected increases. The length of the gap is reduced.

As described above, in a device having a panel structure in which a liquid crystal (especially a chiral smectic liquid crystal) is sandwiched between substrates having a pair of electrodes, driving is caused by a small gap between the substrates and a large capacitance. IC (drive circuit)
The liquid crystal itself is heated in the vicinity of the side on which the drive IC is mounted due to the heat generation. The degree of such heating varies according to the distance from the side on which the drive IC is mounted, and this distance causes a distribution in the temperature of the liquid crystal during driving, and as a result, an excessively uneven distribution in the driving characteristics. Express.

In the device of the present invention, by setting the size of the gap (cell gap) to be smaller as the distance from the side on which the drive IC is mounted becomes larger, specifically, during driving, The intensity of the electric field applied to the liquid crystal is optimally distributed, the distribution of the driving characteristics of the liquid crystal in the panel surface described above is compensated, and the display characteristics are made uniform.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the liquid crystal device of the present invention will be described below with reference to the drawings.

FIG. 1A is a perspective view schematically showing one structural example of the liquid crystal element of the present invention, and FIG.
It is sectional drawing along the line.

The liquid crystal element (liquid crystal panel) is provided with substrates 11a and 11b made of two members such as glass, and the surfaces of these glass substrates 11a and 11b have a predetermined pattern (for example, a thickness of 400 mm). To 3000A), transparent electrodes 12a and 12b are respectively formed to form a matrix electrode structure. These transparent electrodes 12a, 12b
Is In ₂ O ₃ , SnO ₂ or ITO (Indium-Tin Oxide).
e) and the like.

For example, the transparent electrodes 12a and 12b having such a matrix electrode structure correspond to a scanning electrode and an information electrode when multiplex driving is applied, respectively, and at least one end of the substrates 11a and 11b has a driving IC ( A drive circuit (not shown) is mounted (not shown). The drive circuit supplies a scan signal (voltage) and an information signal (voltage) to these electrodes.
C may be mounted on one side of the substrate or on two sides facing each other depending on the number of electrodes and the like.

The transparent electrodes 12a and 12b are provided with alignment control films 14a and 14b via insulating films 13a and 13b as necessary.
b.

The insulating films 13a and 13b are made of, for example, silicon nitride, silicon carbide containing hydrogen, silicon oxide, boron nitride, boron nitride containing hydrogen,
It is made of an inorganic material such as cerium oxide, aluminum oxide, zirconium oxide, titanium oxide, tantalum oxide, magnesium fluoride or other organic insulating materials, and has at least one layer or a multilayer structure as required. Has a function of preventing a short circuit between the opposing substrates (electrodes). Further, a coating type insulating film such as Ti-Si may be formed on the organic or inorganic insulating film for preventing the short circuit.

The alignment control films 14a and 14b are made of polyvinyl alcohol, polyimide, polyamide imide, polyester imide, polyparaxylene, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride,
It can be formed of an organic insulating material such as polyvinyl acetate, polyamide, polystyrene, cellulose resin, melamine resin, urea resin, acrylic resin, photoresist resin, or another inorganic insulating material. The insulating films 13a and 13b and the orientation control films 14a and 14b are not divided into two or more layers as described above, if necessary, and may be a single layer of an inorganic material orientation control layer or an organic material insulation orientation control layer. It can also be.

The insulating films 13a and 13b and the orientation control films 14a and 14b can be formed by an evaporation method in the case of an inorganic system, or a solution in which an organic insulating material is dissolved or a precursor solution (solvent) in the case of an organic system. 0.1-20% by weight, preferably 0.2-10% by weight), using a spinner coating method, a dip coating method, a screen printing method, a spray coating method,
It can be formed by applying by a roll coating method or the like and curing under predetermined curing conditions (for example, under heating).

The insulating films 13a and 13b and the orientation control films 14a and 14b usually have a thickness of 3 to 1000 nm.
Preferably 4 to 300 nm, more preferably 4 to 10 nm
0 nm is suitable.

At least one of the orientation control films 14a and 14b is subjected to a uniaxial orientation treatment such as a rubbing treatment using gauze, an acetate flocking cloth or the like, regardless of whether it is a two-layer or a single-layer.

FIGS. 2A and 2B are schematic diagrams illustrating a rubbing process. The rubbing roller 200 has a structure in which a rubbing cloth 202 such as a nylon cloth is adhered to a cylindrical roller 201. . This rubbing roller 200 is
The glass substrate 11a (11b) (or rubbing roller) is moved in the direction of arrow B by rotating the glass substrate 11a (11b) (or rubbing roller) in the direction of arrow B while rotating in the direction of Sliding contact between 14a and 14b provides an alignment regulating force. The rubbing roller 200 is applied to the substrate 11a (11b)
It is determined by the contact force at the time of contact with the upper alignment control film 14a (14b). Usually, the rubbing roller 200 is moved up and down to change the pushing amount of the rubbing cloth 202, thereby changing the rubbing cloth 202 and the alignment control film 14a (14b). ).

When such a liquid crystal element is applied as a color display element, at least one of the substrates 11a and 11b has a color composed of dots or lines made of various color members such as R, G, B and W. A filter pattern is provided (not shown). This color filter pattern is formed on a substrate, and may be covered with a flattening layer made of an inorganic material or an organic material as necessary in order to reduce a step between lines and dots constituting the pattern.
Further, between the dots and lines of the color filter, a black light-shielding layer made of a metal or a resin material is provided (not shown), preferably to prevent color mixture between colors. In such a color display element, the patterns of the transparent electrodes 11a and 11b can be set according to the number of color filter patterns.

On the other hand, the two substrates 11a and 11b
Spacers 16 are scattered between the glass substrates 11a and 11b. The spacers 16 distribute the glass substrates 11a and 11b over the entire surface of the panel according to the distance from the side on which the driving IC is mounted (cell gap generally). 0.1 to 20 μm, preferably 0.5 to 3 μm).

As the spacer 16, silica beads, alumina beads, polymer films, and glass fibers are used. Further, a granular adhesive (not shown) or the like may be used to promote a function of maintaining a cell gap obtained by a sealant described later and the spacer described above and improve the impact resistance of the element.

The periphery of the substrates 11a and 11b is adhered by a sealant made of a thermosetting resin such as an epoxy-based adhesive (not shown), and these glass substrates 11a and 11b are attached.
A liquid crystal exhibiting, for example, a chiral smectic phase is sealed between b.

In the liquid crystal device, when a liquid crystal exhibiting the above-mentioned chiral smectic phase (preferably, a chiral smectic C phase) is used, it is preferable that the cell gap is made sufficiently small as described above, so that a molecular helical arrangement inherently generated in the same phase. The structure is released, and the molecule is in a state where it can take at least two stable states.

The alignment state of the liquid crystal can be adjusted by appropriately selecting the characteristics of the liquid crystal material, the material of the alignment control films (14a, 14b), the conditions of the uniaxial alignment treatment, and the like.
For example, Japanese Patent Application Laid-Open No. HEI 3-252624 discloses that a fluorine-containing polyimide capable of giving a high pretilt angle (an angle at which liquid crystal molecules are inclined with respect to the alignment control film) of 10 to 30 degrees to liquid crystal molecules is used as an alignment control film. As disclosed, it is possible to stably obtain a C1 uniform alignment state excellent in characteristics such as contrast. In this case, the direction of the uniaxial orientation treatment, preferably the rubbing treatment, applied to each of the orientation control films (14a, 14b) on both substrates is crossed within a range of 20 degrees or less, so that the uniform orientation state is improved. It can be obtained stably.

As the liquid crystal exhibiting the chiral smectic phase, various liquid crystal compounds can be used. A liquid crystal composition using a plurality of liquid crystal compounds having a phenylpyrimidine skeleton and at least one optically active compound can be used. Etc. can be applied. For example, a liquid crystal (composition) exhibiting a cholesteric phase at a temperature higher than the temperature range of the smectic phase can be used.

In the liquid crystal device, the entire region surrounded by the liquid crystal surrounded by the sealant or the region surrounded by the sealant except for a slightly (about 15 mm or less) frame-shaped portion. Function as an effective optical modulation area that can effectively contribute to the optical modulation by the liquid crystal (for example, in a display element, an area that performs optical modulation for actual display).

Incidentally, polarizing plates 17a and 17b are bonded to the outside of the substrates 11a and 11b.

In the liquid crystal element of the present invention (for example, the structure shown in FIG. 1), as described above, as the distance from the side of the substrate (11a, 11b) to which the drive circuit (drive IC) is connected increases. , The cell gap is set to be small.

In the present invention, preferably, in the panel plane,
After a predetermined distribution (the number of spacers per unit area (mm ² ) around a certain point) is set to the dispersion density of the spacers 16 as described above, it is preferable that the distribution is made in a panel type process as described later. The uniform distribution of the cell gap as described above can be controlled by uniformly pressing and bonding the substrates in a plane.
For example, the dispersion density of the spacer is increased near at least one side of the side to which the drive circuit can be connected, and when the drive circuit is not connected to the opposite side, the dispersion density of the spacer near the side is reduced, and When a drive circuit is also connected, the dispersion density of the spacer is set high near both sides, and the dispersion density of the spacer is set low at the center between both sides (the center of the effective optical modulation area).

In the liquid crystal device according to the present invention, the pair of substrates are opposed to each other by a process described later, for example, according to the relationship between the hardness of the spacer and the film provided on each of the pair of substrates sandwiching the spacer. The cell gap is determined after the spacer is slightly cut into the film in contact with the liquid crystal on the substrate when pressure and heat are applied. Here, the pressure applied by the above-mentioned pressurization varies depending on the dispersion density of the spacers, and the degree of immersion in the film of the spacers to be in contact with the liquid crystal varies. Thus, the distribution of the cell gap can be set according to the dispersion density of the spacer.

More specifically, the cell gap is controlled by setting the distribution of the spacer dispersion density in the effective optical modulation area. With reference to one side to which the drive circuit in the effective optical modulation region is connected, the effective optical modulation region in the direction perpendicular to the side (usually, the longitudinal direction of the electrode to which a signal voltage is supplied by the drive circuit connected to the side) It is preferable that the dispersion density of the spacers in a region at a distance of 10% or less of the entire length be higher than the dispersion density of the spacers in a region at least a distance of 30% or more. In particular, when a driving circuit is connected to two sides facing each other, the dispersion density of the spacer in a region at a distance of 10% or less of the entire length of the effective optical modulation region with respect to each side is at least 30%. % Is preferably higher than the dispersion density of the spacers in a region at a distance of 70% or more.

The spacers are sprayed on the substrate (1
1a, 11b) (actually, orientation control films 14, 14b)
This is performed by injecting a spacer from the nozzle facing the upper side while scanning the nozzle. Here, as described above, the nozzle is scanned in a direction perpendicular to one side to which the drive circuit in the effective optical modulation area is connected, and the ejection amount or scanning speed of the spacer from the nozzle is adjusted along the scanning direction. It is possible to set the distribution of the dispersion density of the spacer.

When multiplex driving is applied to the element structure using the matrix electrode structure as described above, the voltage of the scan selection signal is increased from the viewpoint of reducing crosstalk, so that a voltage is supplied to the scan electrode. The heat generated from the drive circuit (drive IC) is extremely high. Therefore, the control of the cell gap distribution by setting the distribution of the spacer dispersion density as described above is performed in the direction perpendicular to the side to which the drive circuit for supplying the voltage to the scan electrodes is connected within the panel surface (usually, the scan direction). It is extremely effective to apply it in the longitudinal direction of the electrode).

An example of a specific manufacturing process of the liquid crystal element of the present invention will be described with reference to FIG.

As shown in FIG. 3A, the transparent electrode 12
a, 12b, insulating films 13a, 13b, and orientation control film 1
A sealant 18 is applied by printing or the like to one peripheral portion of the pair of substrates 11a and 11b on which the 4a and 14b are formed, except for a portion serving as a liquid crystal injection port. Subsequently, on the alignment control film on one of the substrates (the alignment control film 1 in FIG. 3A).
4b), the spacers 16 are dispersed with the dispersion density distribution as described above.

Next, both substrates are arranged to face each other, and FIG.
As shown in (b), the sealant 18 is heated and pressed (P).
And cured to form a bonded cell structure. In FIG. 3B, the right side is the side where the liquid crystal injection port is formed. FIG. 21 shows an example of a planar structure of such a cell structure. In the figure, reference numeral 20 denotes a portion serving as a liquid crystal injection port.

Liquid crystal is injected into the thus obtained cell (empty cell) from a liquid crystal injection port where no sealant is formed. Thereafter, the injection port is sealed with the same material as the sealant. Then, after subjecting the liquid crystal sealed in the cell to a heat treatment or the like as necessary, a drive circuit (drive IC) is connected to an electrode on a predetermined side of the cell (not shown).

In such a process, particularly in the step of applying pressure and heating to both substrates, usually, the heated air existing between the opposed substrates (11a, 11b) causes the heated air shown in FIG. As shown by an arrow 19 in FIG. Here, as shown in FIG. 4, a portion 20 serving as a liquid crystal injection port, that is, a portion where the sealing agent 18 is not applied is provided on a side where the cell gap can be set to be small. If it is 30% or less of the side including the injection port, in the step of heating (and pressurizing) the sealant, depending on the conditions, the facing substrate (1
The heated air 21 existing between 1a and 11b) may not be quickly exhausted from the inlet. Such heated air may apply pressure to the sealant line on the other side to cause damage such as tearing of the sealant. For example, in the structure shown in FIG. 21, when the cell gap is large in the left area on the drawing, the sealant 18a or 18b
May be damaged by excessive expansion of the heated air that could not be evacuated. In this way, stable production of the liquid crystal element is hindered, and the performance of the finally formed element (eg, liquid crystal alignment) may be adversely affected.

In consideration of such matters, in the liquid crystal element of the present invention, it is preferable to form the sealant in a double structure at the periphery of the substrate. In particular, it is preferable that the sealant formed around the region where the cell gap is small has a double structure. For example, as shown in FIG.
It is preferable to form the second sealant 22 along a part of the inside of the second sealant 8. In these portions of the double structure, the sealant may not be in contact with each other. In particular, the structure of the sealant shown in the drawing is particularly suitable when the cell gap is large in the region on the left side of the drawing.

In the liquid crystal element of the present invention, the distribution of the cell gap by the surface width is provided, and particularly when the average cell gap is large, or when the difference between the maximum value and the minimum value of the cell gap is large, the in-plane Excessive chromaticity distribution occurs in the device, and a light source that supplies uniform planar light using the normal transmitted light or on one surface side of the element is provided, and the light from this light source is used for a display device. In such a case, a phenomenon may occur that yellow is colored in a region having a relatively large cell gap (particularly, a region near a side to which the driving circuit is connected).

Therefore, the liquid crystal element (liquid crystal panel) of the present invention
Is applied to a display device as a transmissive liquid crystal display element, a color is applied to the back side of the element (display panel) in order to compensate for the chromaticity distribution caused by the cell gap distribution in the panel plane described above. It is preferable to arrange an illuminating means (backlight) for irradiating plane light having a degree distribution. In this way, in the liquid crystal element, the display characteristics are improved by making the in-plane drive characteristics uniform, and at the same time, the chromaticity in the region near the side where the drive circuit (drive IC) for the scan electrode or the information electrode is connected is particularly increased. It is possible to reduce unevenness.

[0042]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to specific embodiments. Basically, a liquid crystal device having a structure as shown in FIG. 1 described above was prepared according to the following process, and each of the devices was evaluated.

Glass substrate 1 of about 270 mm × 320 mm
The thickness of each of 1a and 11b is set to 1.1 mm, and the IT
The patterns of the transparent electrodes 12a and 12b of O were formed by a sputtering method and photolithography. This transparent electrode 1
The film thicknesses of 2a and 12b were set to 1500 °, and a large number of stripes having a width of 170 μm were provided at intervals of 30 μm. Insulating films 13a and 13 for preventing short circuit on the transparent electrode
b was formed by sputtering using a Ta ₂ O ₅ film to a thickness of 900 °. Further, a coating type insulating layer (TiSi = 1: 1, manufactured by Tokyo Ohka Co., Ltd.) was applied for surface state modification, and baked at 300 ° C. The film thickness was 1200 °.

On the other hand, the alignment control films 14a and 14b are formed by a polyamic acid (LQ1802 manufactured by Hitachi Chemical Co., Ltd.).
Was applied to a solution of NMP / nBC = 1/1 diluted to 1.5 Wt% with a spinner at 2,000 rpm for 20 seconds, and then baked at 270 ° C. for 1 hour.
This film thickness was 200 °.

Next, a rubbing treatment was performed on these alignment control films 14a and 14b using the apparatus shown in FIG.

The rubbing was performed twice under the conditions of a pushing amount ε of 0.35 mm, a roller rotation speed of 1000 rpm, and a roller feeding speed of 30 mm / sec.

The glass substrate 11 manufactured as described above
a and 11b are sprayed on one glass substrate 11a (11b) with a bead spacer 16 (silica beads, alumina beads, or the like) having a predetermined average particle size in a predetermined distribution as described later, and the other glass substrate 11b The two glass substrates 11a and 11b formed by drawing a seal adhesive, which is an epoxy resin adhesive, by a dispenser on the periphery of (11a) are attached to each other, and the sealing material is sealed at 160 ° C., 1 kg / cm ² , and 1 hour. Heating and curing were performed to form a cell having a matrix electrode structure. The bonded glass substrate 11
The rubbing process performed on a and 11b was performed so that the rubbing directions were substantially parallel.

Here, as shown in FIG. 21, the sealant was formed in a line along the periphery of the substrate except for the injection port 20. The size of the region surrounded by the sealing material was set to 257 mm × 315 mm by measuring the center point of the sealing material application width. The width of the sealing material was 0.27 mm. The length of the discontinuous portion serving as the inlet is 1/1 / the length of the side including the inlet.
It was set to 3.

Thereafter, a phenylpyrimidine-based ferroelectric liquid crystal having the following phase transition temperatures and physical properties was subjected to Is pressure reduction under reduced pressure.
The temperature was raised to the o-phase, injected by capillary action, and then gradually cooled to produce a liquid crystal device. When this element was driven and the alignment state was observed, it was observed that the alignment was in a so-called uniform state. The effective optical modulation area is 235 mm.
× 294 mm.

[0050] Tilt angle θ = 15.1 ° (at 30 ° C.) Spontaneous polarization Ps = 5.5 (nc / cm ² ) (at 30 ° C.) Δn = 0.2

Subsequently, one of the transparent electrodes 12a and 12b functions as a scanning electrode, and the other functions as an information electrode, at least at one or both ends of the cell with respect to each of the transparent electrodes 12a and 12b forming the matrix electrode structure. To this end, a driving IC for supplying a scanning signal voltage or an information signal voltage was connected thereto.

Hereinafter, specific experimental examples will be described in detail.

(Experimental Example 1) In accordance with the above-described process,
A liquid crystal element (liquid crystal) having the structure shown in FIG. 1 and schematically having the structure shown in FIG. 6A or 8A (the insulating film and the alignment control film are omitted in these drawings) Display panel sample 1 (FIG. 6) and sample 2 (FIG. 8) were produced. In these samples 1 and 2, the scanning electrode driving IC
(40) is connected to the scanning electrode (11a) on one side of one substrate (11a). Further, a bead spacer (16) having an average particle diameter of 1.2 μm is used, and a scan electrode (11) to which a voltage is supplied by a drive IC (20) is used.
a) Spreader density in direction a) (corresponding to dispersion density)
Have distributions as shown in FIGS. 6B and 8B, respectively, and the change of the cell gap in the scanning electrode direction is
The state is as shown in FIGS. 6C and 8C, respectively.

FIGS. 6 (b), 6 (c), 8 (b), 8 (c)
In the horizontal axis, the total length of the effective optical modulation region of the element in the scanning electrode direction is 1, and the scanning electrode driving IC (40)
Indicates the relative ratio of the distance with respect to the end side on the side where is formed as a reference (0). The spacer dispersion density and the cell gap are values measured on five lines passing through five points at which the side where the scan electrode driving IC is formed are equally divided and orthogonal to the side (n = 5). About scan electrode drive I
This is a value obtained by averaging values at points equidistant from C. That is,
It is based on values measured at 5 × 5 25 points uniformly arranged in the plane (in the effective optical modulation area).

The cell gap is 5 × 5.
The retardation was measured at each of the 25 points (using Olympus optical device RA100), and the retardation was determined based on this value.

For the elements of Samples 1 and 2,
A black-and-white matrix display was performed using drive waveforms (scan selection signal S and information signal I) as shown in FIG. 5, respectively. The driving conditions were as follows: an ambient temperature of 20 ° C. and V _com = 14.1.
V, V _seg = 5.9V, and V _com + V _seg = 20V. During this driving, the temperature distribution of the liquid crystal in the scanning electrode direction, the fluctuation of the threshold value of the driving of the liquid crystal, and the fluctuation of the display quality generated in each sample were evaluated (measurement was performed at the measurement points of the spacer dispersion density and the cell gap described above). T).
The threshold value fluctuation was measured by a threshold value obtained by changing the pulse width of the driving voltage under the above driving conditions, and the relative evaluation was made with the threshold value at one end of the element (at the distance 1) set to 1. About display quality, 10mm at each measurement point
It was evaluated whether the white or black display was uniform at 10 mm.

The temperature distribution in the same direction was reduced, and the threshold was kept substantially uniform. The difference between the highest and lowest temperatures in sample 1 ΔT = 3.9 ° C., and in sample 2 ΔT = 4.9 ° C.
Met. Further, in the device having the setting shown in FIG. 6, the display state of black and white is uniform over the entire surface of the device, whereas in the case of FIG. 8, the optical device near the side on which the drive IC for the scanning electrode is mounted is provided. Display unevenness occurred in the modulation area. Thus, in a liquid crystal element having a matrix electrode structure,
It has been found that the setting as shown in FIG. 6 can significantly reduce display unevenness particularly generated near the driving IC for the scanning electrode.

This result is obtained by increasing the cell gap in the liquid crystal element having the setting shown in FIG. 6, particularly in the area near the side where the scan electrode driving IC is connected, and thereby increasing the capacity of the liquid crystal element in the same area. Is reduced, the flowing current is reduced, the amount of generated heat is suppressed, and it is recognized that this is obtained because the influence of the generated heat of the driving IC is compensated.

(Experimental Example 2) In accordance with the above-described process,
Sample 3 of a liquid crystal element (liquid crystal display panel) having the structure shown in FIG. 1 and schematically having the structure shown in FIG. 10A (the alignment control film and the insulating film are omitted in these drawings).
Was prepared. In this sample 3, the scanning electrode driving IC (40) is connected to the scanning electrode (11a) on both sides of one substrate (11a) (connected to the driving IC on either side by the scanning electrode). Do). Further, a bead spacer (16) having an average particle diameter of 1.2 μm is used, and a spacer scatter density (corresponding to the dispersion density) in the direction of the scan electrode (11a) to which a voltage is supplied by the drive IC (40). Has a distribution as shown in FIG.
In addition, the change of the cell gap in the scanning electrode direction is shown in FIG.
The state is as shown in FIG.

The display in FIG. 10 is the same as in FIGS. 6 and 8.

On the other hand, the IC has the same spacer distribution density and cell gap distribution as the sample 2, and the scan electrode driving IC is connected to the scan electrode (11a) on both sides of one substrate. Sample 4 connected to the driving IC on either side by the scanning electrode).

Experiment 1 was performed on Samples 3 and 4 described above.
Driving was performed under the same conditions as described above, and similarly, the temperature distribution of the liquid crystal in the scanning electrode direction, the threshold fluctuation of the liquid crystal driving, and the fluctuation of the display quality in the panel surface were evaluated. Figure 1 shows the results.
1 (a) and (b) (sample 3) and FIGS. 12 (a) and 12 (b) (sample 4).

By comparing the result shown in FIG. 11 with the result shown in FIG. 12, the scan electrode driving I as shown in FIG.
In the element provided with C on two opposite sides, by setting the dispersion density of the spacer and the distribution of the cell gap in the scanning electrode direction shown in the figure, the temperature distribution in the same direction is reduced, and the threshold value is reduced. Was kept almost uniform. No display unevenness was observed in the panel surface.

In the devices of Experimental Examples 1 and 2, the cell gap was also increased on the side where the information electrode drive IC was connected, and the cell was extended along the direction perpendicular to the side (ie, the direction of the information electrode). Change the gap (reduce the cell gap as the pole from the side increases)
Thereby, further stabilization of display quality over the entire panel is realized.

(Experimental Example 3) An element having the same configuration as that of Sample 1 of Experiment 1 except that the distribution of the spacer dispersion density in the scanning electrode direction and the cell gap distribution due to this were changed. (Display panel) Samples 5 to 10 were produced. In these samples, the distribution of the spacer dispersion density and the tendency of the cell gap distribution are the same as those of the sample 1 (FIGS. 6B and 6C), and the minimum cell gap shown in the following equation (t). Various relations between dmin and the maximum cell gap dmax were set.

[0066]

[Outside 3] The parameter defined by the above formula (I) is such that the approximate average value of the cell gap having a distribution is (dmax + dmin) /
2 shows the ratio of the gap variation value (dmax-dmin) to 2, and indicates the degree of gap variation. For these Samples 5 to 10 and Sample 2, Experiment 1
Driving was performed under the same conditions as described above, and display unevenness and coloring on the panel surface were evaluated. The results are shown in the table below.

[0067]

[Table 1]

From these results, it can be seen that the maximum cell gap dmax and the minimum cell gap thickness dmin of the panel are:

[0069]

[Outside 4] Thus, the color unevenness is good and the display unevenness can be effectively improved.

Further,

[0071]

[Outside 5] It can be seen that color unevenness is also good.

According to the experiment by the present inventors, it was found that
In inch panels,

[0073]

[Outside 6] In order to set the value, the value Smax of the spacer scattering density on the side of the scanning electrode extraction portion and the value Smin of the minimum cell gap portion of the display area of the panel are determined by:

[0074]

[Outside 7] Has been found to be preferable.

(Experimental Example 4) In this example, means for suppressing in-plane coloring phenomena which may be caused by setting the cell gap distribution were examined.

The chromaticity distribution (CIE-xy chromaticity) in the scanning electrode direction was measured for the sample 1 manufactured in Experimental Example 1 and the sample 3 manufactured in Example 3. Specifically, the entire surface of the panel is set to a white display state, BM-7 (manufactured by Topcon) is used as a measuring device, and the center luminance of the panel surface is set to 10 at room temperature.
It was measured as 0 cd / cm ² (uniform planar light). The results are shown in FIGS. 13A (chromaticity x) and (b) for sample 1.
(Chromaticity y) and Sample 3 are shown in FIGS. 14A (chromaticity x) and (b) (chromaticity y). The horizontal axis of these diagrams is synonymous with the horizontal axis of FIG. That is, measurement is performed at points on five lines that pass through five points that equally divide the side on which the scan electrode drive IC is formed and are orthogonal to the side,
The average value of the values at points equidistant from the scan electrode driving IC is calculated. The size of the measurement area at the measurement point was 5 mmφ.

From the results shown in the figure, the distribution of the cell gap in the scanning electrode direction (FIG. 6C, 10
A chromaticity distribution corresponding to (c)) is observed.

A backlight 30 having a structure as shown in FIG. 15 was arranged on the back surface of the devices of these samples. The backlight 30 has a sample 1 in a lamp case 31.
A plurality of lamps 32 are arranged with the longitudinal direction of the side on which the scanning electrode drive IC of the device is provided, and a lighting curtain 33 and a diffusion plate 34 are provided above the lamps 32. Irradiation is performed. And, as the plurality of lamps 32, those having different chromaticities of irradiation light according to the cell gap distribution in the direction of the scanning electrodes of the panel were arranged.

The entire backlight as plane light,
FIG. 16 shows the chromaticity distribution of the panel in the scanning electrode direction.
(A) and (b) (backlight used for sample 1), and FIGS. 18 (a) and (b) (backlight used for sample 3), display with backlight used The chromaticity distribution of the surface is shown in FIGS. 17A and 17B and FIGS. 19A and 19B, respectively.

For reference, a backlight for irradiating plane light having substantially uniform chromaticity on the entire surface is applied to the element having a uniform cell gap of the sample 2, and similarly, the element in the scanning electrode direction on the display surface is similarly applied. The chromaticity distribution was measured. The results are shown in FIGS.

According to these results, by using a backlight having a chromaticity distribution corresponding to the cell gap distribution for a liquid crystal element having a cell gap distribution, an excessive chromaticity distribution on the display surface can be reduced. It is apparent that the level can be reduced as compared with the case where a backlight having a small chromaticity distribution is used, and can be set to a level equivalent to that of a liquid crystal element having a uniform cell gap.

(Experimental Example 5) In this example, the suppression of the damage of the sealant at the peripheral portion which may occur during the manufacture of the device by setting the cell gap distribution was examined.

As shown in FIG. 21, a sealant is formed in a single-layer structure over the entire periphery of the substrate,
Is set to 1 of the length of the sealant on the side where the inlet is provided.
/ 4, and the curing condition of the sealant is 160 ° C., 2 kgf /
A liquid crystal device was prepared in the same manner as in Sample 1 of Experimental Example 1, except that the time was set to 1 cm ² and the time was changed to 1 hour.

In this case, in the manufacture of ten elements, up to eight pieces of the sealant were peeled off in the direction of the electrode intersecting the sealant near the region 17a and 17b in FIG.

On the other hand, the pattern of the sealant is shown in FIG.
Except that the width of the injection port 20 is set to 1/4 of the length of the sealant provided with the injection port and the conditions for heat curing of the sealant are as described above. A liquid crystal device was manufactured under the same design and conditions as in Example 1. Here, the width of the sealant 22 was set to 0.15 mm, and the distance to the sealant 18 was set to 4.6 mm. In this case, none of the ten elements produced peeling of the sealant.

As a result, the distribution is provided in the cell gap, and particularly when the liquid crystal injection port is formed on the side where the cell gap is set to be small, by forming the sealant in a double structure with respect to the liquid crystal element, The liquid crystal device can be more stably obtained even under severe conditions of heat curing of the sealant, and the obtained device has a long-term and stable display quality as demonstrated in Experimental Example 1 and the like. It is clear that it will be secured.

[0087]

As described in detail above, according to the present invention,
In a liquid crystal element and a liquid crystal display device using the same, an excessively non-uniform temperature distribution in a liquid crystal panel surface caused by heat generation in the vicinity of a portion where a driving IC or the like is mounted is eliminated, and display in the surface is eliminated. The unevenness is improved.

[Brief description of the drawings]

FIG. 1A is a perspective view showing an example of a structure of a liquid crystal element of the present invention. FIG. 1B is a cross-sectional view along the line AA in FIG.

FIG. 2A is a perspective view illustrating a rubbing process applied in manufacturing a liquid crystal element of the present invention. (B) Sectional drawing explaining the rubbing process applied in manufacture of the liquid crystal element of this invention.

FIGS. 3A and 3B are cross-sectional views illustrating a manufacturing process of the liquid crystal element of the present invention.

FIG. 4 is a perspective view schematically showing a state of exhaust from between the substrates in the liquid crystal element of the present invention.

FIG. 5 is a diagram showing driving waveforms used in an embodiment of the present invention.

FIG. 6A is a diagram schematically showing the structure of an element of Sample 1 according to an example of the present invention. (B) The figure which shows the distribution of spacer distribution density in sample 1. (C) A diagram showing the cell gap distribution in sample 1.

7A is a diagram showing a temperature distribution in a device of Sample 1. FIG. (B) A diagram showing a threshold distribution in the element of Sample 1.

FIG. 8A is a diagram schematically showing the structure of a sample 1 according to an example of the present invention. (B) The figure which shows the distribution of spacer distribution density in sample 2. (C) A diagram showing a cell gap distribution in sample 2.

9A is a diagram showing a temperature distribution in a device of Sample 2. FIG. (B) A diagram showing a threshold distribution in the element of Sample 2.

FIG. 10A is a diagram schematically showing the structure of a sample 3 according to an example of the present invention. (B) The figure which shows the distribution of spacer distribution density in sample 3. (C) The figure which shows the distribution of the cell gap in sample 3.

11A is a diagram showing a temperature distribution in a device of Sample 3. FIG. (B) A diagram showing a threshold distribution in the element of Sample 3.

12A is a diagram showing a temperature distribution in an element of Sample 4. FIG. (B) A diagram showing a threshold distribution in the element of Sample 4.

13A and 13B are diagrams showing chromaticity distribution on a panel surface when a backlight of uniform plane light is applied to the element of sample 1. FIG.

14A and 14B are diagrams showing a chromaticity distribution on a panel surface when a backlight of uniform plane light is applied to the element of Sample 3. FIG.

FIG. 15 is a cross-sectional view schematically showing a structure of a backlight used for a liquid crystal element in an example of the present invention.

16A and 16B are diagrams showing a chromaticity distribution of only a backlight used for an element of Sample 1 in an embodiment of the present invention.

17A and 17B are diagrams showing a chromaticity distribution when the backlight having the chromaticity distribution shown in FIG. 16 is applied to the element of Sample 1;

FIGS. 18A and 18B are diagrams showing a chromaticity distribution of only a backlight used for an element of Sample 3 in an embodiment of the present invention.

FIGS. 19A and 19B are diagrams showing a chromaticity distribution when the backlight having the chromaticity distribution shown in FIGS.

FIGS. 20A and 20B are diagrams showing a chromaticity distribution only in the element of Sample 2. FIGS.

FIG. 21 is a plan view showing an example of an arrangement of a sealant in the liquid crystal element of the present invention.

FIG. 22 is a plan view showing another example of the arrangement of the sealant in the liquid crystal element of the present invention.

[Explanation of symbols]

 11a, 11b Substrate 12a, 12b Electrode 13a, 13b Insulating film 14a, 14b Alignment control film 15 Liquid crystal 16 Spacer 17a, 17b Polarizing plate 18 Sealant 20 Liquid crystal inlet

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tetsuro Saito 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Akihiko Komura 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside the corporation

Claims (19)

[Claims] A liquid crystal exhibiting a chiral smectic phase is sandwiched between a pair of substrates each having an electrode and facing each other with a predetermined gap therebetween, and a voltage for driving the liquid crystal is supplied to at least one side of the substrate. A liquid crystal element having a portion to which a drive circuit is connected, wherein the gap decreases as the distance from at least one of the sides to which the drive circuit is connected increases. 2. An electrode formed on one of the substrates is a scanning electrode, an electrode formed on the other substrate is an information electrode, these electrodes form a matrix electrode structure, and a voltage is applied to the scanning electrode. 2. The liquid crystal element according to claim 1, wherein the gap becomes smaller as the distance from the side where the supply driving circuit is formed becomes larger. 3. The gap between the pair of substrates is large enough to cancel a helical arrangement of liquid crystal molecules inherently present in the liquid crystal exhibiting the chiral smectic phase. The liquid crystal element according to the above. 4. A method according to claim 1, wherein the pair of substrates face each other via a plurality of spacers, and a dispersion density of the spacers is changed according to a distance from at least one of the sides to which the drive circuit is connected. 2. The liquid crystal device according to 1. 5. The liquid crystal device according to claim 1, wherein the dispersion density of the spacer is reduced as the distance from at least one of the sides to which the drive circuit is connected is increased. 6. The pair of substrates face each other via a plurality of spacers, and the dispersion density of the spacers changes according to a distance from a side to which a drive circuit for supplying a voltage to the scan electrodes is connected. 3. The liquid crystal device according to claim 2, wherein: 7. The liquid crystal device according to claim 6, wherein the dispersion density of the spacer is reduced as the distance from a side connected to a drive circuit for supplying a voltage to the scanning electrode is increased. 8. The liquid crystal element according to claim 2, wherein a driving circuit for supplying a voltage to the scanning electrode is formed on only one side. 9. The liquid crystal device according to claim 2, wherein drive circuits for supplying a voltage to the scan electrodes are formed on two sides facing each other. 10. The liquid crystal device according to claim 1, wherein the pair of substrates are bonded to each other with a sealant formed at a peripheral portion thereof, and the sealant has a double structure at least in part. 11. When the maximum cell gap dmax and the minimum cell gap dmin are defined as follows: 2. The liquid crystal device according to claim 1, having the following relationship. 12. The relationship between a maximum cell gap dmax and a minimum cell gap dmin is expressed as follows: The liquid crystal device according to claim 11, wherein: 13. A drive for providing a liquid crystal between a pair of substrates facing each other with a predetermined gap therebetween via a spacer and providing electrodes for driving the liquid crystal to at least one side of the electrodes. A liquid crystal element having a portion to which a circuit is connected, wherein a dispersion density of the spacer is changed according to a distance from at least one side to which the driving circuit is connected. 14. The liquid crystal device according to claim 13, wherein the dispersion density of the spacer is reduced as the distance from at least one of the sides to which the drive circuit is connected increases. 15. An electrode formed on one of the substrates is a scanning electrode, an electrode formed on the other substrate is an information electrode, and these electrodes form a matrix electrode structure, and supply a voltage to the scanning electrode. 14. The liquid crystal device according to claim 13, wherein a dispersion density of the spacer is changed according to a distance from a side on which the driving circuit is formed. 16. The liquid crystal element according to claim 13, wherein the dispersion density of the spacer is reduced as the distance from a side to which a drive circuit for supplying a voltage to the scanning electrode is connected increases. 17. A liquid crystal is sandwiched between a pair of substrates each having an electrode and facing each other with a predetermined gap therebetween via a spacer, and a voltage for driving the liquid crystal is supplied to at least one side of the substrate. A method for manufacturing a liquid crystal element having a portion to which a driving circuit is connected, wherein at least a part of the peripheral portion of one of the substrates has a double structure except for a portion for injecting the liquid crystal between the substrates. A step of forming an agent pattern; and a step of spraying a spacer on one of the pair of substrates with a dispersion density having a distribution according to a distance from at least one side of the side to which the drive circuit is connected; A sealant pattern is formed, a pair of substrates on which spacers are scattered are opposed to each other, and a sealant is cured by applying heat and pressure, and a step of bonding the pair of substrates,
A method for manufacturing a liquid crystal element comprising: 18. A drive for providing a liquid crystal between a pair of substrates each having an electrode and facing each other with a predetermined gap therebetween via a spacer, and supplying a voltage for driving the liquid crystal to the electrode on at least one side. A liquid crystal element having a portion to which a circuit is connected, wherein the gap between the substrates is changed according to a distance from at least one of the sides to which the drive circuit is connected; and a back surface of the liquid crystal element. Side, with respect to the liquid crystal element,
A liquid crystal display device comprising: illumination means for irradiating plane light having a chromaticity distribution according to a change in the gap between the substrates. 19. A liquid crystal display comprising a pair of substrates, each having an electrode and facing each other via a spacer with a predetermined gap therebetween, and supplying a voltage for driving the liquid crystal to at least one side of the substrate. A liquid crystal element having a portion to which a circuit is connected, wherein the liquid crystal element changes a dispersion density of the spacer according to a distance from at least one of sides to which the driving circuit is connected; and a back surface of the liquid crystal element. Side, with respect to the liquid crystal element,
A liquid crystal display device comprising: illumination means for irradiating plane light having a chromaticity distribution according to a change in the dispersion density of the spacer.