JPH08304761A - Color liquid crystal display device - Google Patents

Abstract

PURPOSE: To widen a driving margin and to make well display even under any use conditions by supplying scanning signals to the electrodes on a flattening film and supplying information signals corresponding to every color to information electrodes formed finer than these electrodes. CONSTITUTION: Color filters 3 are formed via an undercoating layer 2 on an insulating substrate 1a and the flattening layer 4 is formed thereon. Further, scanning electrodes consisting of striped transparent electrodes 6a and auxiliary electrodes 7a are formed via a barrier layer 5 on its surface. A shorting preventive layer 8a, a rough surface forming layer 9a and an oriented film 10a are formed thereon. On the other hand, the information electrodes consisting of the transparent electrodes 6b and auxiliary electrodes 7b finer than the scanning electrodes are formed on an insulating substrate 1b. A shorting preventive layer 8b, a rough surface forming layer and an oriented film 10b are formed thereon. Both substrates 1a, 1b are disposed to face each other and chiral smectic liquid crystals 13 are held between the substrates. The scanning electrodes are supplied to the scanning electrodes and the information signals corresponding to every color of the color filters 3 are supplied to the information electrodes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal element used for a display device for displaying characters and images, and more particularly to a liquid crystal display device for full color display using a chiral smectic liquid crystal.

[0002]

2. Description of the Related Art Conventionally, a color liquid crystal display device having a red (R), green (G), and blue (B) filter in a stripe shape, and each of the R, G, and B filters is halved.
What has a mosaic filter in which a non-colored (W) filter is provided in addition to a mosaic filter having a pitch shift, R, G, and B is used. Since such a filter is usually provided on the inner surface of the glass substrate, the laminated structure of the films provided on the upper and lower glass substrates is different from that of the black and white liquid crystal display device.

On the other hand, a chiral smectic liquid crystal used for a ferroelectric liquid crystal or an anti-ferroelectric liquid crystal is in one alignment state when an electric field of one polarity is applied to a certain reference potential level, and when an electric field of the other polarity is applied. The other orientation state is obtained. Such characteristics are significantly different from those of the conventional TN type liquid crystal, and a liquid crystal display device for color display utilizing the characteristics is being developed.

FIG. 14 shows a cross section of a conventional binary display (black and white) liquid crystal element using a ferroelectric liquid crystal. 1a, 1 in the figure
b is an insulating substrate, 6a and 6b are transparent electrodes, 7a and 7b are auxiliary electrodes, 8a and 8b are short-circuit preventing layers, 9a and 9b are rough surface forming layers, 10a and 10b are alignment layers, 11 is adhesive beads, 12 Is a spacer bead, and 13 is a liquid crystal layer. The drive electrodes, which are composed of the transparent electrodes 6a and 6b and the auxiliary electrodes 7a and 7b, are each formed in a stripe shape, and form a matrix so as to face each other so as to be orthogonal to each other. In addition, one pixel is from the dotted line to the dotted line in the figure.

[0005]

The potential energies of the two orientation states of the chiral smectic liquid crystal must be symmetrical, but if the structures of the inner surfaces of the upper and lower glass substrates are different as described above, the potential energies are different. Energy may be asymmetric. The potential energy asymmetry tends to cause a threshold asymmetry that switches from one orientation state to the other.

Although such a technical problem hardly occurs in the conventional nematic liquid crystal, it becomes a problem in the chiral smectic liquid crystal because of different characteristics. In particular, the asymmetry of the switching threshold tends to narrow the selection range (driving margin) for selecting the voltage level, pulse width, and frequency of the waveform of the driving signal.

Therefore, in a color display device using a chiral smectic liquid crystal, it is necessary to find out a parameter having a great influence on the drive margin and select it appropriately.

An object of the present invention is to provide a color display device which has a wide driving margin and can perform a good display under any conditions of use.

[0009]

A feature of the present invention is that a chiral film is provided between a pair of electrode substrates, one of which has a color filter, a flattening film and a striped electrode on the substrate and the other of which has a striped electrode. A liquid crystal display device sandwiching a smectic liquid crystal, wherein the other electrode is formed thinner than the electrode on the flattening film, and means for supplying a scanning signal using the electrode on the flattening film as a scanning electrode, There is a means for supplying an information signal corresponding to each color of the color filter by using the electrode as the information electrode.

According to the present invention, by adopting the above-mentioned structure, the condition that easily influences the drive margin is fixed, so that a wide drive margin is secured, and good display can be performed under all usage conditions.

[0011]

FIG. 17 is a block diagram of a color display device according to an embodiment of the present invention. In the figure, 107 is a graphic controller, and the data sent from this is input to the scanning signal control circuit 104 and the information signal control circuit 106 through the drive control circuit 105 and converted into address data and display data, respectively. The scanning signal applying circuit 102 generates a scanning selection signal waveform and a scanning ratio selection signal waveform according to the address data, and applies the scanning selection signal waveform and the scanning ratio selection signal waveform to the scanning electrodes of the display unit 101 including 1280 × 1024 pixels. Further, the information signal applying circuits 103 arranged above and below according to the display data are
The G, B, and W information signal waveforms are generated and applied to the information electrodes having a width narrower than that of the scanning electrodes of the display unit 101.

Next, the structure of the display unit 101 is shown. 1 is a schematic plan view of a liquid crystal element which is an example of the display unit of FIG. 17, FIG. 2 is a sectional view taken along the line AA ′, and FIG. 3 is a sectional view taken along the line BB ′. In the figure, the area surrounded by the dotted line is one pixel, and
a and 1b are insulating substrates, 2 is an undercoat layer, 3 is a color filter forming a predetermined pattern, 4 is a flattening layer, 5 is a barrier layer, 6a and 6b are transparent electrodes, and 7a and 7b.
Are auxiliary electrodes, 8a and 8b are short-circuit prevention layers, and 9a and 9b
Is a rough surface forming layer, 10a and 10b are alignment layers, 11 is adhesive beads, 12 is spacer beads, 13 is a liquid crystal layer, and 14 is a light shielding layer. In FIGS. , The lower side is called the second substrate. Note that FIG. 1 is a plan view seen from the first substrate side. In the present invention, the drive electrode on the first substrate is the scanning electrode, the second substrate side is the information electrode,
A scanning signal and an information signal are applied respectively.

The observer side of the material may be set to either the first substrate or the second substrate, but it is preferably the first substrate side having the color filter film.

Hereinafter, each part of the liquid crystal device shown in FIGS. 1 to 3 will be described in detail along with a manufacturing process with reference to the drawings.

First, the first substrate will be described.

Step-a (FIG. 15 (a)) As the insulating substrate 1a, a substrate having excellent transparency, which is generally commercially available as glass for liquid crystal, can be used, and examples thereof include soda lime glass and non-alkali glass. To be Preferably, one having one surface polished is used. The thickness and size are appropriately selected depending on the screen size and how many panels are taken from one sheet.
When manufacturing a 4.8 inch liquid crystal device, 1.1
A material having a thickness of about mm is used.

Step-b (FIG. 15 (a)) In the present invention, an undercoat layer 2 is preferably provided on the surface of the insulating substrate 1a to prevent the elution of alkali from the glass. The undercoat layer 2 only needs to have a protective effect on the lower layer, for example, SiO ₂ , MgO, Si.
_{N, TiO 2, Al 2 O} 3, ZrO are used, 200
Used with a thickness of 1000Å.

Step-c (FIG. 15 (a)) The insulating substrate 1a having the undercoat layer 2 formed on the surface thereof is subjected to at least one of pure water shower, pure water + ultrasonic cleaning, brush, etc. After washing and drying for various times and combinations, organic substances are removed by UV irradiation.

Step-d (FIG. 15 (a)) The light-shielding layer 14 shown in FIG. 3 has a stripe pattern (black stripe) as shown in FIG. The shape can be appropriately used. The material of the light-shielding layer 14 is excellent in light-shielding property including metals such as Cr and Mo, alloys thereof, Cr ₂ O ₃ such as oxides, and organic materials such as resin in which black pigment is dispersed. Materials can be used. Thickness is 500-1500Å
The range is set according to the light-shielding ability of the material. For example, when a metal is used, the light blocking effect can be obtained even if the thickness is thin. In the present invention, a Mo-Ta alloy layer is preferably used,
It is preferably used at 1000 Å or less. The light shielding layer 14 is obtained by stacking the material on the entire surface of the substrate by sputtering, coating or the like and then patterning. Specifically, a resist selected according to the adhesion to the material is applied to the surface of the light-shielding layer by spinner, printing, etc., prebaked at 70 to 120 ° C., exposed at 90 to 120 mJ, developed, washed and dried. After that, etching is performed with an etching solution such as an acid depending on the material of the light-shielding layer and cleaning is performed. Then, the resist is peeled off and further cleaning is performed.

The light-shielding layer 14 can be formed up to the vicinity of the sealant described later, leaving a small amount of non-light-shielding portion, and this portion can be used for the inspection of the liquid crystal alignment state.

Step-e (FIG. 15 (b)) In the present invention, the color filter 3 preferably forms white (W) in addition to green (G), red (R) and blue (B). As the forming method, there are a dyeing method, a pigment dispersion method, an electrodeposition method and the like, and any of them can be used in the present invention, but the pigment dispersion method will be described as an example. For example, a color resist of a photosensitive resin in which a desired pigment (no pigment is added to W) is dispersed is applied to a thickness of 1.0 to 2.0 μm with a spinner, a coater or the like, and after leveling at a constant temperature, Pre-bake at around 80 ° C. The temperature and holding time at this time, and the thickness to be applied are appropriately selected depending on the resist material. Then 20
Exposure is performed at 0 to 1000 mJ. The degree of exposure is R, G, B,
Since the sensitivity varies depending on W, the exposure time is changed and adjusted. After the exposure, it is developed with a developing solution, a method and a temperature according to the resist material, post-baked at 120 to 250 ° C. and washed. For example, as shown in FIG. 4, each color filter is formed with a gap of several μm so as not to contact the pattern of the light shielding layer 14 formed previously and the adjacent color filter. Further, in addition to the display area as a whole, the non-display area around the display area is formed so as not to be covered with the sealant near the edge of the substrate, which will be described later. Here, the pattern shapes (size of the color filters) of the color filters inside and outside the display area may be different from each other, and for example, one unit can be made larger outside the display area than inside the display area.
The forming process is sequentially performed for each color of each color filter, and the order is appropriately selected depending on the material used.

Step-f (FIG. 15C) Next, a flattening layer 4 for filling the gaps between the color filters and flattening the surface is formed. In the present invention, the flattening layer 4 is coated with a flattening material by a spinner, printing, coater or the like so that the maximum thickness (t in FIG. 2) is 1.5 to 5 μm, and then at 60 to 150 ° C. Formed by leveling and post-baking at 150-330 ° C if necessary (these temperatures are set by the planarizing material). The flattening material may be an inorganic material or an organic material as long as it is capable of flattening the step formed by the color filter 3 and the light shielding layer 14 and is resistant to the subsequent steps, and has heat resistance and chemical resistance. Specific examples thereof include polyamide, epoxy resin, and organic silane-based resin, and of these, organic silane-based resin is preferably used.

In the present invention, the thickness (T) of the liquid crystal layer 13
Is smaller than the maximum thickness (t) of the flattening layer. With this structure, the generation rate of voids generated when the liquid crystal is injected is reduced, and the production yield is improved. Further, in the liquid crystal element of the present invention, the diameter of the spacer beads 12 described later is larger than the thickness (T) of the liquid crystal layer 13, and the spacer beads 12 are fixed so as to be embedded in both substrates. Therefore, it is desirable that the substrate has a pencil hardness of about 7H or less so as to be filled with the spacer beads, and the hardness of the flattening layer 4 is more preferably in the range of 3H to 7H. The pencil hardness is a value obtained by measurement according to a method using a pencil hardness measuring device according to JIS-K5401. Further, the flattening layer 4 is preferably formed up to the lower side of the sealing agent described later. With this configuration, the liquid crystal can be easily injected, and a defective product due to defective injection of the liquid crystal can be prevented from being produced during manufacturing.

Step-g (FIG. 15 (c)) A barrier layer 5 is formed on the surface of the flattening layer 4, and the color filter 3 is protected in subsequent steps such as film forming step and etching. The material of the barrier layer 5 is not limited as long as it has a protective effect.
O ₂ , MgO, SiN, TiO ₂ , Al ₂ O ₃ , ZrO and the like are preferably used. The thickness of the barrier layer 5 is 100, for example.
It is formed at a thickness of about 1000 Å by a method suitable for the material such as printing or spattering.

The above is the process for the first substrate only, and the following processes are common to the first and second substrates. Also, the second
The insulating substrate 1b of the substrate is generally made of the same material as the insulating substrate 1a of the first substrate.

Step-h (FIGS. 15C and 16)
(A)) As the transparent electrodes 6a and 6b, a layer made of a transparent conductive material such as ITO is formed by sputtering, vapor deposition, firing or the like.
It is preferable to use SnO ₂ of 5 to 10% with respect to In ₂ O ₃ , but it may be appropriately selected depending on the transmittance and the conductivity. The thickness of the transparent electrodes 6a and 6b is, for example, 300 to 30.
The value is 00Å, and the thickness is also selected depending on the optical characteristics and resistance of the liquid crystal used. Similar to the light shielding layer 14, the ITO layer is patterned by photolithography to have a desired shape, in particular, a pattern corresponding to a pixel on the first substrate and a color filter on the opposite substrate on the second substrate (for example, the first substrate). The substrate is formed in a stripe shape corresponding to between the light shielding layers 14 shown in FIG. 4, and the second substrate is formed in a shape shown in FIG. However, as the etching solution, an aqueous solution of iron chloride, hydroiodic acid, hypophosphorous acid, or the like is used. It is preferable that the transparent electrode 6a on the side of the first substrate is patterned correspondingly not only on the display region but also on the color filter 3 formed.

In this step, by forming the wiring also outside the display area, the resistance can be measured without affecting the drive electrodes. FIG. 11A shows the wiring 41 provided on the second substrate, and the wiring is similarly provided on the first substrate.

Further, the weir 4 having a substantially L shape shown in FIG.
2 has the function of blocking the layer formed by coating in the subsequent step, and can prevent the solution from flowing out unnecessarily. Further, the weir (pattern) 43 shown in FIG. 11 (b) is preferably formed on the second substrate side in parallel to the liquid crystal injection port described later, so that the liquid crystal can be injected easily and uniformly as described later. Has the effect of The weirs 42 and 43 need not be formed of ITO as long as they have the above-described action, but they can be formed simultaneously when the transparent electrode is formed, which is advantageous in the manufacturing process.

Step-i (FIGS. 15D and 16)
(B)) Auxiliary electrodes 7a and 7b for reducing the wiring resistance of the transparent electrodes 6a and 6b are formed (FIGS. 15D and 16).
(B)). The material is a metal, and Cr, Al, Mo, or an alloy thereof, Mo-Ta, or the like is used. In addition, the transparent electrode 6
In consideration of the adhesiveness with a and 6b, the resistance, and the adhesiveness with the resist, a multilayer structure may be used. Specifically, it is Mo / Al or Mo / Al / Mo-Ta. Especially in the case of a multilayer structure, the etching speed differs depending on the material,
The material is selected in consideration of etching in the subsequent process. For example, when simultaneously etching the above three-layer structure, Mo-
Ta5-10% (for example 200-500Å) / Al alloy (for example 200-1500Å) / Mo-Ta10-20
% (For example, 100 to 500 Å) has a good compatibility with the etching solution. Further, the multilayer structure may be formed by stacking layers while etching each layer.

The above metal is laminated on the entire surface of the substrate, and the steps of resist coating, exposure, development, post baking, etching, and resist stripping are sequentially carried out. For example, in the first substrate, the transparent electrode 6a is overlaid. And an auxiliary electrode 7a (FIG. 5) having an opening on the color filter 3, and a second
In the substrate, the auxiliary electrode 7b overlapping the end of the transparent electrode 6b
(FIG. 7) is formed. The auxiliary electrode 7b may be formed over the entire surface of the transparent electrode 6b outside the display area.

Further, outside the display area, pad portions for short circuit inspection are provided at both ends of each drive electrode. 9 shows the pad portion of the second substrate, and FIG. 10 shows the pad portion of the first substrate.
In the figure, 31 is a drive electrode of the second substrate, 32 is a drive electrode of the first substrate, and 33 is a pad portion. Although not shown in FIG. 9, a pad portion is also formed on the other end of the drive electrode 32, and the same configuration as that of FIG. 9 is adopted. The pad portion 33 is a portion where the lower transparent electrodes 6a and 6b are exposed without forming the auxiliary electrode in the region where the auxiliary electrodes 7a and 7b are originally formed. Since each drive electrode 31, 32 is very fine,
The inspection terminal for short-circuit inspection is also a thin terminal needle adapted to this, and there is a risk that the electrode may be damaged when it comes into contact with the drive electrodes 31 and 32, or the inspection terminal may not be placed on the particularly fine drive electrode 31. As shown in FIGS. 9 and 10, by providing a pad portion 33 exposing a transparent electrode such as ITO which is harder than metal, drive electrodes 31, 32 by inspection terminals are provided.
Damage is prevented. Further, as shown in FIG. 9, particularly in the fine drive electrodes 31, the pad portions 33 are staggered.
And the width of the pad portion 33 is widened, the inspection terminal can be easily mounted. Incidentally, as shown in the figure, it is preferable to expose the lower electrode such as ITO in the narrow portion of the electrode adjacent to the pad portion. Further, as shown in FIG. 10, in the drive electrode 32, the auxiliary electrode 6a is formed at the end portion to suppress an increase in wiring resistance.

After forming the auxiliary electrodes 7a and 7b, the wiring 41 and the pad portion 33 are used to measure the wiring resistance and inspect for a short circuit.

Step-k (FIG. 15 (e) and FIG. 16)
(C)) Short-circuit prevention layers 8a and 8b are formed on the wiring. The short-circuit prevention layers 8a and 8b are insulating layers for preventing a short circuit between the upper and lower substrates, and an organic or inorganic insulating film is formed on the entire surface of the substrate by sputtering, coating, baking or the like. _{Specifically, Ti-Si, SiO 2,} TiO 2, Ta 2 O 5 is used, these have a single layer, it is possible to use a multilayer.
For example, a multilayer structure in which Ta ₂ O ₅ is formed by sputtering to 500 to 1200Å and a solution of a coating type insulating film material such as Ti-Si is printed and baked to form an insulating layer of 500 to 1000Å is preferably used. . The short-circuit prevention layer 8a,
8b is formed up to the outside of the sealing area described later.

Step-1 (FIG. 15 (e) and FIG. 16)
(C)) In order to prevent movement of liquid crystal molecules during device driving, rough surface forming layers 9a and 9b are formed to roughen the alignment film surface described later. The rough surface forming layers 9a and 9b are made of Si of 300 to 700Å
The O ₂ beads are obtained by dispersing 5 to 30% by weight in an insulating film solution having a ratio of Ti-Si = 1: 1 and printing and firing using a color spreading plate. The film thickness is preferably 100 to 300Å, and is formed up to the outside of the sealing region.

Step-m (FIG. 15 (e) and FIG. 16)
(C)) Alignment films 10a and 10b for controlling the alignment of liquid crystal molecules
To form. The material of the alignment film is selected from polyvinyl alcohol, polyimide, polyamideimide, etc., coated or printed on the entire surface of the substrate, baked at 200 to 300 ° C., and has an insulating layer only inside the sealing region with a thickness of 50 to 100 Å. Form. Such an insulating layer is formed on the entire surface in the sealing region and, if necessary, on the region corresponding to the display region, for example. A roller wrapped with a raised rubbing cloth is pressed against the surface of the insulating layer (alignment film), and the rotation speed is 500 to 2000 rp.
While rotating at m, the surface of the insulating layer (alignment film) is rubbed to form alignment films 10a and 10b. As the material of the rubbing cloth, natural fibers such as cotton, aramid, nylon,
It is selected from synthetic fibers such as rayon, Teflon, polypropylene and acrylic, and among them, aramid fiber is preferably used. During the rubbing treatment, a mask may be provided on, for example, the frame portion (outer periphery) of the insulating layer, and the surface of the insulating layer may be rubbed without the frame portion. The rotation direction and feed rate of the roller are appropriately selected depending on the degree of rubbing treatment. After the rubbing process, both substrates are washed.

Step-n (FIG. 13 (a)) One substrate, preferably the first substrate surface (the surface of the alignment film)
Adhesive beads 11 are sprinkled on. The adhesive beads 11 have no tackiness at room temperature and under the driving condition of the element, and exhibit tackiness in various treatments such as heat treatment at the time of bonding substrates to be described later. The adhesive beads 11 are made of an adhesive made of a thermosetting resin or the like that does not affect the liquid crystal, such as epoxy resin or acrylic resin. The diameter of the adhesive beads 11 is preferably 2 to 10 μm, and the beads are dispersed in a solvent such as isopropyl alcohol and sprayed at about 50 to 130 beads / mm ² . Moreover, the adhesive beads 11 are adhered to both substrates after the substrates are sealed. As will be described later, the positions where the first substrate and the second substrate are cut are shifted to expose the terminals at the end portions of the substrate. If the adhesive beads 11 are present, the part to be cut off adheres to the other substrate via the adhesive beads 11. Therefore, it is preferable that the adhesive beads 11 are not in the region to be cut and cut off. It is preferable to apply only in the corresponding areas.

Step-o (FIG. 8) On the other substrate, preferably the surface of the second substrate (for example, the surface of the alignment film), the seal pattern shown in FIG. In the figure, 21 is a sealant, 22 is a liquid crystal inlet, and 23 is a dummy wall described later. As the sealant 21, for example, a thermosetting resin material such as a thermosetting epoxy resin is used, and drawing is performed with a dispenser. The drawing method is not limited to this, and is appropriately selected depending on the material of the sealant, such as screen printing. The width may be set in consideration of the cell thickness and the thickness at the time of printing. The dummy wall 23 is not limited to being provided in the vicinity as shown in FIG. 8, and the formation location can be appropriately changed according to the conditions such as the liquid crystal material to be used. For example, the dummy wall 23 is formed on the opposite side of the injection port 22. May be. Further, in FIG. 8, when the color filter is formed in the non-display area outside the display area, the dummy wall 23 can be provided at a position corresponding to the filter or a position outside the filter forming area. At this time, it is preferable to form a dummy wall outside the filter formation region from the viewpoint of the cell gap.

Step-p (FIG. 13A) Spacer beads 12 are scattered on a substrate different from the substrate on which the adhesive beads are scattered, preferably on the surface of the substrate on which the sealant is drawn. The diameter of the spacer beads 12 is selected to be larger than the cell thickness, but is preferably in the range of 0.6 to 3.5 μm. For example, when the cell thickness is 1 μm, 1.
Select beads having a diameter of about 2 to 1.3 μm. As beads, silica beads and alumina beads are preferably used.
It is sprinkled on the entire surface of the substrate so that the number becomes 00 / mm ² . As such a solvent, it is preferable to select and use a spacer bead having a low melting property. In the present invention, beads having a diameter larger than the setting of the liquid crystal layer thickness are finally used as spacers, so that the beads are fixed between the substrates in a state that they are half embedded in the substrate surface. Later movement of the beads is prevented, and a uniform liquid crystal layer thickness is maintained.

Step-q As shown in FIG. 13, the substrate on which the adhesive beads 11 are dispersed is fixed, and the substrate on which the spacer beads 12 are dispersed is added so that the alignment films 10a and 10b are on the inside. The pressure is applied for 10 to 120 minutes to heat the adhesive beads 11 and the sealant 21 to bond both substrates. That is, the adhesive beads 11 and the spacer beads 12 are dispersed on another substrate, and the substrate on the side on which the adhesive beads 11 are dispersed is fixed and bonded, so that the adhesive beads 11 are biased or detached from the substrate surface in the process. Don't worry. Further, since the spacer beads 12 have a diameter much smaller than that of the adhesive beads 11, the spacer beads 12 are attached to the surface of the substrate even when the substrate is turned upside down.
The spacer beads 12 are neither biased nor fall off from the substrate. By this step, the substrates are bonded together in a state where both the adhesive beads 11 and the spacer beads 12 are uniformly dispersed.

Step-r Scribing is performed by shifting the cutting positions of the first substrate and the second substrate so that the mounting terminal portions are exposed, and the excess substrate is removed. Also, for example, immediately before scribing, a barcode label or the like can be attached to the vicinity of the position corresponding to the injection port on both substrates to identify the substrates.

Step-s Chiral smectic liquid crystal is injected into the liquid crystal cell obtained in the above step. First, put the liquid crystal cell in the vacuum device,
The liquid crystal is attached to the inlet while the cell is sufficiently evacuated. Next, pressure is gradually applied in this state to draw the liquid crystal into the liquid crystal cell at a constant speed as much as possible.

In the present liquid crystal element, the thickness (t) of the flattening layer 4 is larger than the thickness (T) of the liquid crystal layer 13, so that the liquid crystal layer is not as thick as the conventional element having no flattening layer. The void generation rate is low, and the yield in the liquid crystal injection step is improved. Further, in this element, since the flattening layer 4 is formed up to the lower side of the sealant 21 as described above, the liquid crystal can be easily injected, and the manufacturing yield is further improved. Further, as shown in FIG. 11B, the weir 43 is formed of ITO in the liquid crystal cell, and the liquid crystal is outwardly extended along the weir 43 as shown by an arrow in FIG. 12A. Spreads and prevents the formation of bubbles. FIG. 12B shows the flow of liquid crystals in the conventional liquid crystal cell. Further, even if bubbles are generated, the bubbles are pushed between the dummy wall 23 drawn by the sealant 21 and the outer sealant 21, so that there are no bubbles in the display area and a defective product is generated. The rate can be kept low.

As the liquid crystal exhibiting a chiral smectic phase which can be used in the present invention, a liquid crystal composition containing a plurality of liquid crystal compounds and at least one optically active compound (chiral dopant) is preferably used. Examples of preferable liquid crystal compounds that compose the liquid crystal composition include liquid crystal compounds having the structures of the following general formulas 1 to 5 (including optically active compounds), and these are the main constituent components, A liquid crystal composition can be prepared by appropriately changing the compounding ratio of each liquid crystal compound. still,
The liquid crystal compound as used herein is not limited as to whether or not it exhibits liquid crystal properties by itself, and may be any compound that appropriately functions as a liquid crystal component in a liquid crystal composition.

[0044]

Embedded image

P and q are 0, 1, 2 and p + q
Is 1 or 2, and R ₂₁ and R _{22 each} have 1 to 18 carbon atoms.
Is a linear or branched alkyl group, and one or two or more methylene groups in the alkyl group are -O-, -S-, -CO-, -under the condition that hetero atoms are not adjacent to each other. C
HW -, - CH = CH - , - C≡C- may be replaced by, W is a halogen, CN, a CF _3.

Further, R ₂₁ and R ₂₂ may be optically active.

Y ₁ represents hydrogen or fluorine.

[0048]

Embedded image

Y ₁ represents hydrogen or fluorine, and R
₂₃ is a linear or branched alkyl group having 1 to 18 carbon atoms, and R ₂₄ is a hydrogen atom, a halogen, a CN group, or a linear or branched alkyl group having 1 to 18 carbon atoms. An alkyl group, and one or two or more methylene groups in the alkyl group represented by R ₂₃ and R ₂₄ are —O—, —S—, —CO—, —CHW under the condition that hetero atoms are not adjacent to each other. -, -C
H = CH -, - may be replaced by C≡C-, W denotes halogen, CN, a CF _3. Also, R
₂₃ and R ₂₄ may be optically active.

[0050]

Embedded image

R ₂₅ and R ₂₆ are linear or branched alkyl groups having 1 to 18 carbon atoms, and 1 of the alkyl groups is
Or two or more methylene groups are -O-, -S-, -CO-, -CHW under the condition that hetero atoms are not adjacent to each other.
-, - CH = CH -, - may be replaced by C≡C-, W denotes halogen, CN, a CF _3.

Further, R ₂₅ and R ₂₆ may be optically active.

[0053]

[Chemical 4]

R ₂₇ and R ₂₈ are linear or branched alkyl groups having 1 to 18 carbon atoms.
Or two or more methylene groups are -O-, -S-, -CO-, -CHW under the condition that hetero atoms are not adjacent to each other.
-, - CH = CH -, - may be replaced by C≡C-, W denotes halogen, CN, a CF _3.

Further, R ₂₇ and R ₂₈ may be optically active.

[0056]

Embedded image

R ₂₉ and R ₃₀ are linear or branched alkyl groups having 1 to 18 carbon atoms, each of which is 1
Or two or more methylene groups are -O-, -S-, -CO-, -CHW under the condition that hetero atoms are not adjacent to each other.
-, - CH = CH -, - may be replaced by C≡C-, W denotes halogen, CN, a CF _3.

Further, R ₂₉ and R ₃₀ may be optically active.

More preferable examples of the compounds of the general formulas 1 to 4 are shown below.

More Preferred Compound Examples of Compounds of General Formula 1

[0061]

[Chemical 6]

More Preferred Compound Examples of Compounds of General Formula 2

[0063]

[Chemical 7]

More preferred examples of the compound of formula 3

[0065]

Embedded image

More preferred examples of the compound of formula 4

[0067]

[Chemical 9]

R is a hydrogen atom, a halogen, a CN group, or a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, one of which is 2 or 2
One or more methylene groups are -O-, -S-, -CO-, -CHW-, -CH = CH under the condition that hetero atoms are not adjacent to each other.
May be replaced by-, -C≡C-, W
Represents halogen, CN, or CF ₃ . Further, R may be optically active.

Y ₁ represents hydrogen or fluorine.

The upper and lower substrates are sealed with a sealing agent (not shown), and as the sealing agent, for example, a thermosetting epoxy resin is used.

Next, a method of driving the liquid crystal device of this embodiment will be described.

18 to 24 are timing charts showing drive signal waveforms used in the present invention. In the figure, A is a scanning selection signal waveform, B is a scanning non-selection signal waveform, and C and D are information signal waveforms, which correspond to bright or dark, respectively. 1
H is one horizontal scanning period. blk is an erase pulse for erasing (resetting) the pixel on the selected scan electrode,
win is a write pulse for determining the display state of the pixel on the selected scan electrode. The composite waveform of the write pulse and the information signal is applied to the liquid crystal of the corresponding pixel, and it is determined whether the pixel continues the display state by the erase pulse or changes from the display state by the erase pulse to the other display state. To be done.

When a high frame frequency is desired in FIGS. 21 to 24, it is preferable to use the waveforms shown in FIGS. In addition, a preferable waveform is appropriately used according to the flicker of the screen and the size of the required drive margin.

FIG. 25 is a waveform showing an information signal applied to a certain information electrode, which is a waveform when only one of the dark signal and the bright signal is continuously applied over a plurality of consecutive horizontal scanning periods. is there. In FIG. 25, a waveform AA is an AC waveform in which a positive polarity pulse a and a negative polarity pulse b having a width of ΔT are continuously and alternately applied, and is a waveform in which C or D in FIGS. 21 and 22 is continuous.

On the other hand, the waveform BB in FIG. 25 is a waveform in which a pause period of (1/2) ΔT is provided between the pulses a of the waveform AA,
The waveform CC is a waveform in which a similar rest period is provided between the pulses b, and both have the same effective value.
C and D are continuous waveforms. AA, B
When each waveform of B and CC was applied and observed,
The degree of fluctuation of the liquid crystal molecules changes depending on the waveform, and when the direction of inversion due to the negative voltage is changed from the U1 state to the U2 state, it largely fluctuates by the pulse b, that is, the negative pulse in the U1 state, and largely by the pulse a in the U2 state. I found it to shake.

It should be noted that such a fluctuation appears as a color change of the display color, especially in a color display device.

Therefore, consider a waveform that reduces the number of times the pulse b is applied to a pixel in the U1 state. As shown in FIGS. 23 and 24, the information signal has a pause period in of (1/2) ΔT in
When t is entered, the DC pulse b is not applied other than the write pulse for the U2 state even if C or D in FIGS. 23 and 24 continues. That is, if there is another pixel that displays the U1 state on the same information electrode, the number of times the DC pulse b is applied is reduced by one per frame. When all the pixels on the same information electrode display the U1 state, the DC pulse b is 1
It is not applied even once, that is, the CC waveform in FIG. 25 is obtained. Similarly, when all the pixels on the same information electrode display the U2 state, the BB waveform is obtained. Therefore, the fluctuation that has conventionally limited the driving margin is suppressed, and the color change due to the fluctuation is not recognized, and as a result, the driving margin can be widened.

Further, when the relationship between the idle period and the driving margin was examined at intervals of (1/2) ΔT, as shown in FIG. 26, the width of the driving margin was saturated when the idle period was around (1/2) ΔT. I found out that I would do it. This measurement is 1
0 ° C., driving conditions V ₁ = 14.3 v, V ₂ −14.3
_{v, V 3 = 5.7v, V} 4 = -5.7v, V 5 = 6.4
v, V ₆ = 0.8 v, and the display unit 101 of the present embodiment is set.
Is a range in which a good display can be obtained. In order to increase the frame frequency, it is preferable that the pause period is as short as possible. Therefore, from the viewpoints of both margin and speed, (1/2) ΔT is appropriate for the pause period.

Although the relationship between the width of the idle period and the drive margin may be finely divided and measured precisely, the ratio of the idle period to each pulse width may be a simple integer due to the configuration of the drive circuit. It is desirable to set. The reason is that 1H is divided to output the drive waveform and the reference pulse of the drive circuit system is set so as to be an integral multiple of the selection pulse, the auxiliary pulse, or the idle period, so the pulse width ratio becomes too complicated. And the clock becomes very fast. As a result, it is necessary to make a circuit with a response speed faster than necessary, and to avoid cost increase.

That is, in the present invention, the U1 state, U2
When the selection period is ΔT, the number of times of application of a pulse that greatly fluctuates in each state is at least (1/2) Δ
This can be suppressed by including the quiescent period of T, so that it is possible to secure the drive margin, increase the frame frequency, and simplify the drive circuit.

FIG. 23 or FIG. 24 shows the display device of this embodiment.
Driving condition V ₁ = 1 at a temperature of 10 ° C.
_{4.3v, V 2 = -14.3v, V} 3 = 5.7v, V 4 =
-5.7v (V ₅ = 6.4v), set [Delta] T = 80 [mu] s, was driven, could excellent display over the display section 101 entirely.

Further, when the temperature becomes higher than the predetermined temperature, by using the drive signals shown in FIGS. 18 to 22, one horizontal scanning period is shortened and the display speed can be increased.

[0083]

As described above, according to the present invention,
It has a wide drive margin, and can be adapted to any use condition to perform good display. Further, by selecting a drive waveform, high-speed drive or high-quality image display in which flicker on the screen is prevented is possible.

[Brief description of drawings]

FIG. 1 is a schematic plan view of a liquid crystal element that is an example of a display unit according to an embodiment of the present invention.

2 is a cross-sectional view taken along the line AA ′ of the liquid crystal element shown in FIG.

3 is a cross-sectional view of the liquid crystal device shown in FIG. 1 taken along the line BB ′.

FIG. 4 is a diagram showing a color filter and a light shielding layer of the liquid crystal element shown in FIG.

5 is a diagram showing an auxiliary electrode on the first substrate side of the liquid crystal element shown in FIG.

6 is a diagram showing a transparent electrode on the second substrate side of the liquid crystal element shown in FIG.

7 is a diagram showing auxiliary electrodes on the second substrate side of the liquid crystal element shown in FIG.

8 is a diagram showing a seal pattern of the liquid crystal element shown in FIG.

9 is a diagram showing a short circuit inspection pad portion on the second substrate side of the liquid crystal element shown in FIG.

10 is a diagram showing a short circuit inspection pad portion on the first substrate side of the liquid crystal element shown in FIG.

11 is a diagram showing dummy wirings and weirs provided on the second substrate of the liquid crystal element shown in FIG.

FIG. 12 is a diagram showing a flow of liquid crystal when liquid crystal is injected into the liquid crystal element shown in FIG. 1 and a conventional liquid crystal element.

13 is a diagram showing a substrate bonding process of the liquid crystal element shown in FIG.

FIG. 14 is a diagram showing a cross-sectional view of a binary display ferroelectric liquid crystal device.

FIG. 15 is a diagram showing a manufacturing process of the first substrate of the liquid crystal element shown in FIG. 1.

16 is a diagram showing a manufacturing process of the second substrate of the liquid crystal element shown in FIG. 1. FIG.

FIG. 17 is a block diagram of a display device according to an embodiment of the present invention.

FIG. 18 is a timing chart showing an example of drive signal waveforms of the display device according to the embodiment of the present invention.

FIG. 19 is a timing chart showing an example of drive signal waveforms of the display device according to the exemplary embodiment of the present invention.

FIG. 20 is a timing chart showing an example of drive signal waveforms of the display device according to the embodiment of the present invention.

FIG. 21 is a timing chart showing an example of drive signal waveforms of the display device according to the embodiment of the present invention.

FIG. 22 is a timing chart showing an example of drive signal waveforms of the display device according to the embodiment of the present invention.

FIG. 23 is a timing chart showing an example of drive signal waveforms of the display device according to the embodiment of the present invention.

FIG. 24 is a timing chart showing an example of drive signal waveforms of the display device according to the embodiment of the present invention.

FIG. 25 is a diagram showing an information signal waveform in which only one information signal is continuous.

FIG. 26 is a diagram showing a relationship between a rest period and a drive margin.

[Explanation of symbols]

 1a, 1b Insulating substrate 2 Undercoat layer 3 Color filter 4 Flattening layer 5 Barrier layer 6a, 6b Transparent electrode 7a, 7b Auxiliary electrode 8a, 8b Short prevention layer 9a, 9b Rough surface forming layer 10a, 10b Alignment layer 11 Adhesion Beads 12 Spacer beads 13 Liquid crystal layer 14 Light-shielding layer 21 Sealant 22 Filling port 23 Dummy walls 31, 32 Drive electrode 33 Pad part 41 Dummy wiring 42, 43 Weir 101 Display part 102 Scan signal applying circuit 103 Information signal applying circuit 104 Scanning Signal control circuit 105 Drive control circuit 106 Information signal control circuit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical indication location G09F 9/35 330 7426-5H G09F 9/35 330 G09G 3/36 G09G 3/36 (72) Invention Yuichi Masaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yoshinori Shimamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazuya Ishiwatari Canon Inc., 3-30-2 Shimomaruko, Ota-ku, Tokyo (72) Inventor Kazunori Katakura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (1)

[Claims] 1. A liquid crystal display device in which a chiral smectic liquid crystal is sandwiched between a pair of electrode substrates, one of which has a color filter, a flattening film and a striped electrode on a substrate and the other of which has a striped electrode. Then, the other electrode is formed thinner than the electrode on the flattening film, and means for supplying a scanning signal using the electrode on the flattening film as a scanning electrode,
A color liquid crystal display device comprising means for supplying an information signal corresponding to each color of a color filter using the other electrode as an information electrode.