JP2003029265A - Liquid crystal panel, manufacturing method therefor and liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain satisfactory display and low power consumption. SOLUTION: First areas 1B and 2B and second areas 1A and 2A are provided between a front substrate 1 with an electrode and a rear substrate 2 with an electrode, a second liquid crystal layer 7 of a chiral nematic liquid crystal is interposed between an alignment layer 3A and an alignment layer 4A, a first liquid crystal layer 6 having 63 deg. twist alignment is interposed between an alignment layer 3b and an alignment layer 4B, a boundary sealing part 5C is provided between the two liquid crystal layers 6 and 7, voltage is applied independently to the electrodes of the respective liquid crystal layers from driving devices 15 and a polarizing plate 8, a quarter wave plate, a reflection film 9 and a color layer 11 are provided. Only one optical state is stably held in the first liquid crystal layer 6 and two or more optical states are stably held in the second liquid crystal layer 7, when no voltage is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal panel having a plurality of liquid crystal layers having different operation modes between a pair of substrates, a method of manufacturing the same, and a liquid crystal display device having the liquid crystal panel.

[0002]

2. Description of the Related Art Liquid crystal display devices are required to simultaneously display various information. For example, JP-A-58
In 193419, a liquid crystal display device is used for an electronic odometer of an automobile, and is configured to simultaneously display a date, a time display, a cumulative mileage, and a fuel remaining state (conventional example 1). ).

Further, in Japanese Patent Laid-Open No. 62-121486, display patterns such as print characters and figures are provided on the back side substrates of a pair of substrates arranged opposite to each other, and the display patterns are displayed when no voltage is applied. Has been done. Then, the liquid crystal portion is optically turned on and off to cover the display pattern or display it again for variable display (conventional example 2).

Further, a ferroelectric liquid crystal display device having a memory type operation mode and a chiral nematic liquid crystal display device are also known (conventional example 3). The feature is that the display can be held even when no voltage is applied. However, these display elements have not been widely used as a general-purpose liquid crystal display device because their driving waveforms are more complicated than those of TN liquid crystals and STN liquid crystals and the driving voltage is large.

[0005]

Liquid crystal display devices are widely used as display devices for portable devices, public display devices, display devices for personal computers, and display devices for consumer equipment or industrial equipment. However, depending on the nature and content of the display information to be displayed, rewriting of the display is extremely small and rewriting is frequently performed. In that case, when the performance of the entire display device is evaluated, there is a problem that the power consumption required for rewriting the display is large.

In the liquid crystal display devices of Conventional Example 1 and Conventional Example 2,
It is necessary to constantly drive the display surface formed integrally with one liquid crystal panel, whether the display information is partially rewritten or the same display information is held. Therefore, it was not possible to achieve a comprehensive reduction in power consumption.

Further, the liquid crystal display device of Conventional Example 3 has an advantage that power consumption is very small when no voltage is applied. However, when the display is frequently rewritten, it is necessary to continuously apply the high voltage pulse, and power consumption is required accordingly.

Usually, most of the power consumption of a liquid crystal display device is
It is consumed by the driving circuit and the light source, and the power consumption by the liquid crystal layer itself is relatively small. If the power consumption required for driving the power-saving liquid crystal display device can be suppressed, the power consumption can be further reduced.

In this case, it is necessary to optimize the display mode and drive according to the content of the display information required for the liquid crystal display device. Generally, line-sequential driving is performed on a matrix electrode group used for TN liquid crystal or STN liquid crystal.
Also, in the case of the segment type electrode structure, the multiplex drive is performed. When the driving frequency and the crest value of the voltage pulse are high, the power consumption tends to increase.

The present invention intends to provide a plurality of pieces of display information having different rewriting frequencies, which are difficult in the conventional example, as an efficient and good-looking display. For example, the present invention provides a preferable liquid crystal display device when it is attempted to display display information that changes with time and display information that is relatively unchanged on the same display screen.

An object of the present invention is to improve the overall performance of a liquid crystal panel and a liquid crystal display device, reduce the power consumption of the entire device, and to obtain a liquid crystal display device which is easy to manufacture and has good productivity. . Further, by providing a liquid crystal display device that uses a liquid crystal panel that is always driven when performing a display and a liquid crystal panel that has a memory-type operation mode and can hold the display when no voltage is applied, a new usage method is provided. It is a thing.

[0012]

That is, according to the first aspect of the present invention, a first region and a second region are provided between a front substrate with an electrode and a back substrate with an electrode, and the front substrate in the first region is provided. A first liquid crystal layer is sandwiched between the front substrate and the back substrate, and a second liquid crystal layer is sandwiched between the front substrate and the back substrate in the second region, which are independent of the first liquid crystal layer and the second liquid crystal layer. An electrode is arranged so that a voltage can be applied to the first liquid crystal layer, and only one optical state is stably maintained in the first liquid crystal layer when no voltage is applied, and two or more electrodes are provided in the second liquid crystal layer when no voltage is applied. A liquid crystal capable of maintaining an optical state is provided.

In the second aspect, the alignment ability generated in the first liquid crystal layer by the liquid crystal contact surface on the front substrate side and the liquid crystal contact surface on the back substrate side, and the liquid crystal contact surface on the front substrate side and the liquid crystal on the back substrate side. The liquid crystal panel according to aspect 1, wherein the alignment ability generated in the second liquid crystal layer differs depending on the contact surface.

In the third aspect, when the liquid crystal layer is sandwiched by using the same liquid crystal material in the first region and the second region, the alignment ability generated in the first liquid crystal layer and the second liquid crystal. Aspect 1 in which a combination of liquid crystal contact surfaces that makes the alignment abilities generated in the layers substantially equal is provided on the front substrate and the back substrate, and different liquid crystal materials are used for the first liquid crystal layer and the second liquid crystal layer.
The liquid crystal panel described in 1.

Aspect 4 is such that the first liquid crystal layer has a thickness of 30 to 3
A liquid crystal panel according to aspect 1, 2 or 3, which has a twisted orientation of 00 ° and in which at least one polarizing plate is arranged corresponding to the first liquid crystal layer.

The fifth aspect is the first, second, third or fourth aspect.
A liquid crystal display device including the liquid crystal panel and the driving device described in 1 above, wherein the frequency of rewriting display to the first liquid crystal layer is higher than the frequency of rewriting display to the second liquid crystal layer.

In a sixth aspect, a liquid crystal contact surface having a horizontal alignment ability and a liquid crystal contact surface having a vertical alignment ability or a non-alignment ability are divided into regions on at least one of the front substrate with electrodes and the back substrate with electrodes. A method for manufacturing a liquid crystal panel, which comprises forming a first liquid crystal layer having only one optical state when no voltage is applied and a second liquid crystal layer having two or more optical states when no voltage is applied. provide.

In the above liquid crystal panel, the first liquid crystal layer has a liquid crystal having a twist orientation of 30 to 300 ° (hereinafter, referred to as a liquid crystal).
It is called TN-LC. ), And the second liquid crystal layer is a chiral nematic liquid crystal or a cholesteric liquid crystal (hereinafter,
It is called CL-LC. ) Is preferable.

CL-LC may be either a polymer-containing type or a polymer-free type, but it is preferable to use the polymer-free type because the production is easy. Usually, it is prepared to have a helical pitch that selectively reflects visible light.

Further, a light absorbing layer or a black layer for absorbing at least a part of visible light is provided on the back side substrate (substrate opposite to the observing side) of the second liquid crystal layer having a bistable optical state. Is preferred.

The liquid crystal contact surface used in the above liquid crystal panel has an alignment film formed by any one of a rubbing alignment method, a photo-alignment method, an oblique deposition method, a transfer alignment method and a non-alignment method. Is preferably a surface of U (for example, U as a prior art example relating to an alignment film).
See S6156232).

Further, in the present invention, as the non-aligned liquid crystal contact surface, a base film which is in contact with the liquid crystal layer such as a flattening film or an insulating film is provided in addition to a polymer film such as polyimide which has not been rubbed. The surface of may be used as it is as a liquid crystal contact surface.

The main liquid crystal contact surface for twisting the liquid crystal is preferably the surface of a rubbing-treated polymer film having a pretilt angle of 10 ° or less.

The main liquid crystal contact surface for making the liquid crystal layer in the bistable state is basically any surface of a substrate constituent material normally used in a liquid crystal cell when it is not rubbed. It can also be used.

However, in order to secure a good brightness level, it is preferable to use a vertically aligned liquid crystal contact surface.
For example, a polymer film having a pretilt angle of 60 ° or more is preferable. In particular, it is preferable to use a vertical alignment film. Alternatively, the surface of the base film can be used as it is without using the liquid crystal contact surface of the polymer film. However, the viewing angle tends to be rather limited.

Table 1 below shows the presence or absence of bistability of CL-LC depending on the combination of liquid crystal contact surfaces. In the table, the boundary film such as an alignment film or a base film having a liquid crystal contact surface is abbreviated as OC, the planar state is abbreviated as PL, the focal conic state is abbreviated as FC, and the complete planar state exhibiting specular reflection is abbreviated as a complete PL.
Means that there is bistability, and x means that there is no bistability.

[0027]

[Table 1]

Normally, the orientation ability of the sandwiched liquid crystal layer is determined by the orientation ability of the liquid crystal contact surface on each of the front substrate side and the back substrate side. In one aspect of the present invention, when trying to form different liquid crystal layers between a pair of substrates, one substrate side is divided into a plurality of regions within the substrate surface, and a liquid crystal contact surface for each region between the front and back substrates is formed. It is possible to change the alignment ability, give main alignment characteristics to each liquid crystal layer, and provide the liquid crystal contact surfaces in a plurality of regions on the other substrate surface in common.

For example, in order to twist-align the liquid crystal layer, a polymer film having a rubbing-processed liquid crystal contact surface with a pretilt angle of 10 ° or less is provided in one region on one substrate side, and the other region is non-aligned. Provide a membrane. Then, the entire liquid crystal contact surface on the other substrate side is formed by the non-alignment film. As the non-alignment film, the base film can be used as it is. Alternatively, a polymer film may be provided and used without orientation treatment.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION A "clock display" will be described as an example of a display including display information having different rewriting frequencies. In the present invention, the "second display" segment is displayed by the first liquid crystal layer, and each "hour display / minute display" segment is displayed by the second liquid crystal layer capable of stably holding two or more optical states. do. The second liquid crystal layer has a so-called memory type operation mode. When the two liquid crystal layers are used for display, the reference of the rewriting frequency of the display information may be selected and set from about 1 second to about 1 minute. Also,
It can be adjusted depending on the application.

As the liquid crystal, nematic liquid crystal TN-LC can be used for the first liquid crystal layer, and CL-LC having a bistable operation mode can be used for the second liquid crystal layer. Generally, Δn of a nematic liquid crystal having a positive dielectric anisotropy
Is about 0.08 to 0.3, and by selecting Δn of the liquid crystal, T
Adjust Δn · d of N-LC.

At this time, if the twist angle is less than 30 °, the change in the state of white / black becomes small, so that it becomes difficult to perform display. If the twist angle exceeds 300 °, the change in chromaticity becomes large and it becomes difficult to perform a constant display, so the above angle range is set. In addition, under the condition of this angle range, design is performed so as to provide a display within a desired contrast ratio and an allowable chromaticity change.

Then, a plurality of liquid crystal layers having different operation modes are provided in one liquid crystal panel and combined with an external driving device to form a liquid crystal display device. Then, it provides a good-looking display and achieves low power consumption.

Next, the basic structure of the liquid crystal panel of the present invention will be described. First, the inside of one liquid crystal panel is divided by the boundary seal portion. Then, different liquid crystal materials are arranged in the respective divided areas.

For example, the second region 1A having a memory CL-LC or the like and the first region 1B having a non-memory TN-LC or the like are formed in advance to form the front substrate 1. Similarly, the back substrate 2 in which the second region 2A and the first region 2B are formed is prepared, and the boundary seal portion 5C is provided in addition to the normal peripheral seal portion to provide a plurality of liquid crystal layers between the pair of substrates. (See FIG. 1).

Further description will be given with reference to FIGS.
In the first regions 1B and 2B provided with the non-memory liquid crystal, in order to form the first liquid crystal layer 6 in which the liquid crystal is twist-aligned at 30 to 300 °, an alignment film 3B having a low pretilt angle which is rubbed is formed. Use 4B. On the other hand, no alignment film for twist alignment is used for the second liquid crystal layer 7 in the second regions 1A and 2A including the liquid crystal having a memory property. Instead, an alignment film that is not rubbed or a vertical alignment film that is rubbed may be used, or the surface of the base film may be directly used as the liquid crystal contact surfaces 3A and 4A.

This is because the orientation film for twist orientation tends to act so as to impair the bistable optical state of the PL state or FC state of CL-LC. A boundary seal portion 5C is provided between the second regions 1A and 2A and the first regions 1B and 2B.

Thus, in the present invention, a plurality of liquid crystal layers are formed between the pair of substrates with electrodes. At this time, the cell gap of the liquid crystal layer is common. In the present invention, in consideration of the range of normally usable driving voltage, it is preferable to set the cell gap in the range of 3.0 to 6.0 μm. Since both TN-LC and CL-LC are used, it is necessary to select the range that exhibits the preferable performance of both. Particularly preferably, it is set to 3.5 to 5.5 μm. This is to further select a range in which both display characteristics are good.

At this time, if the TN-LC has a reflective structure as shown in FIG. 2, the gap of the liquid crystal cell can be made thinner than that of the transmissive structure shown in FIG. In FIG. 2, the left side of the liquid crystal panel is TN-LC, and the polarizing plate 8 and the λ / 4 plate 1
0, the front substrate 1, the front side alignment film 3B, the first liquid crystal layer 6 twist-aligned at 60 to 63 °, the back side alignment film 4B, and the reflection film 9. This is an example of a reflection type configuration in which the angle of the rubbing axis between the front and back substrates is set to 60 to 63 °. With this configuration, it is possible to exhibit the same function as that of the transmissive configuration having the 90 ° twist orientation. A driving device 15 is provided outside the liquid crystal panel, and its driving output terminals are independently connected to the electrodes of the liquid crystal panel.

On the other hand, in FIG.
The cross section of LC is typically shown. A front polarizing plate 8F, a front substrate 1, a front alignment film 3B, a 90 ° twist-aligned first liquid crystal layer 6, a back alignment film 4B, a back substrate 2, and a back polarizing plate 8R are provided. Illustration of a light source arranged on the lower part or the entire surface of the back substrate is omitted. It should be noted that description of members common to each drawing is omitted.

Below, TN-LC is used as the liquid crystal arranged in the first region, and CL-L is used as the liquid crystal arranged in the second region.
Configuration examples A to E of the present invention will be described by taking the case of using C as an example. In the present invention, a plurality of liquid crystal layers having different operation modes are arranged between a pair of substrates. At that time, since the value of Δn · d in TN-LC and the driving voltage in CL-LC are almost proportional to the cell gap d, the gap of the liquid crystal cell is determined. At this time, in CL-LC, selective reflection occurs at a specific wavelength λ determined by the liquid crystal pitch p and the average refractive index n _AVG (λ = n _AVG · p).

In the present invention, the boundary film having a liquid crystal contact surface includes a case where an electrode or a base film is used in addition to the alignment film in which a polymer film such as polyimide is positively provided. Particularly, a film having a substantially flat film surface in which the surface of the resin film or the like has not been rubbed is referred to as a non-alignment film.

(Structural Example A) An alignment film having a low pretilt angle of 0 to 10 ° is provided only in the first region 1B. Second area 1
A is the state where the surface structure of the base film such as the electrode or the insulating film or the substrate with the electrode is unchanged. Then, the entire surface of the substrate is rubbed so that the rubbing directions are orthogonal to each other between the two substrates holding the liquid crystal. At least one polarizing plate is installed at a position corresponding to the non-memory LC region, and a display with a predetermined contrast ratio is developed.

In this configuration example, since the alignment film obtained by rubbing the resin film is not provided on the interface of the second region, the manufacturing is extremely easy. The variation in display contrast ratio tends to be slightly large. FIG. 7 shows the relationship between the substrates according to this configuration example. In the diagram (A), a resin film is formed, and rubbing is performed in the direction of the arrow. Diagram (B) shows rubbing orientation (horizontal orientation) on a part of the substrate after rubbing.
3 shows a state in which an alignment film having is formed.

(Structure example B) An alignment film having a low pretilt angle is provided on the entire surface. The rubbing process is not performed on the second region 1A, and the rubbing process is performed only on the first region. Then, at least one polarizing plate is installed at a position corresponding to the region where the non-memory type liquid crystal is arranged. This configuration example has the advantages over the configuration example A that the optical characteristics of the second liquid crystal layer having a memory property are stable and that the type of alignment film can be freely selected.

For example, the surface hardness is determined by the pencil hardness test method (J
IS K 5400, JIS S6006, JIS R
(See 6252) and "B" or less, and using an alignment film material that is softer than the conventional one can prevent display burn-in. However, partial rubbing on the substrate surface is indispensable, and the manufacturing process increases accordingly.

FIG. 8 shows this configuration example. The partial drawing (A) shows a state in which a resin film is formed, and a partial rubbing process is performed in the direction of the arrow. Diagram (B) shows a state after rubbing, in which an alignment film having a horizontal alignment capability is formed in the first region 1B of the non-memory LC, and the second region 1A of the memory LC is formed.
A non-alignment film is formed on.

(Structural Example C) A polymer film (non-oriented polymer film) which is not subjected to rubbing treatment is provided on the entire surface of the cell. Then, the TN-LC is arranged in the first region 1B and the CL-LC is arranged in the second region 1A to form a liquid crystal panel.
The optical characteristics of CL-LC are good, and are the same as those of a single-piece liquid crystal element.

In the first region, a twisted structure having a specific pitch has a multi-domain structure in which the directions of the orientation axes (helical axes) are dispersed in the substrate surface. However, if the polarizing plates are arranged in the crossed Nicols state in the first region, a contrast ratio of about 10 can be achieved. This configuration example does not require rubbing treatment at all, and has excellent productivity (see FIG. 9).

(Structure example D) An alignment film having a low pretilt angle is provided in the first region 1B, and an alignment film having a high pretilt angle of 60 to 90 ° is provided in the second region 1A. Next, the entire surface of the substrate is rubbed in the direction of the arrow to form a backside substrate (a substrate opposite to the observation side) (see FIG. 10). Subdivision (A) of FIG.
The left side shows the state where the alignment film with the low pretilt angle is formed and the right side shows the state where the alignment film with the high pretilt angle is separately formed, and FIG.

As the front substrate (observation side substrate), a substrate formed by separately coating an alignment film having a low pretilt angle and a high pretilt angle is used as it is without rubbing treatment, or
A substrate provided with an alignment film having a low pretilt angle on the entire surface, or a base film such as an electrode insulating film or a substrate having a lower structure as it is is used without rubbing treatment.

In this constitutional example, it is necessary to separately coat the alignment film, and the number of steps is slightly increased. However, since the rubbing step which requires manufacturing precision can be performed by "entire surface rubbing", the production method is different from the partial rubbing method. It has good properties and can suppress variations in display performance of products.

(Structure example E) By using an alignment film (vertical alignment film) having a high pretilt angle, the bistability of CL-LC can be maintained even when rubbing alignment is performed (see FIG. 11). However, in order to prevent a narrow viewing angle of the display due to regular reflection from the back substrate side, a non-rubbing orientation alignment film is essential on the front substrate side.

In the case of this configuration example, the contrast ratio of the first region can be set higher than that of configuration example C. The relationship between the above-described vertical alignment film and bistability is shown by the present inventors in Japanese Patent Application No. 2000-162649.

Examples 1 to 6 will be described below. Example 1 is a reference example using two liquid crystal panels, Examples 2A to 2D and 5 are examples of the liquid crystal panel according to the present invention, and Examples 3 and 4 are examples of the liquid crystal display device.

[0056]

EXAMPLES (Example 1) A TN liquid crystal display device was manufactured as follows. Two substrates provided with a transparent conductive film (ITO) were prepared, and the transparent conductive film of each substrate was etched to have a shape corresponding to the second display, an electrode line interval, and the number of electrodes to form an electrode group. .

Next, an electrically insulating layer is formed on the transparent electrode,
Furthermore, polyimide (model number: LX-58) is formed on the electric insulation layer.
(Hitachi Chemical Co., Ltd.) polymer solution was applied and baked to form a polyimide film. Then, the polyimide films of the upper and lower substrates were rubbed in one direction so that they were orthogonal to each other. The film thickness was 300Å, and a horizontal alignment film having a pretilt angle of about 2 ° was formed.

Spacers of resin beads having a diameter of 8 μm were scattered between the electrode facing surfaces of the two substrates with electrodes. After that, a peripheral sealing material made of an epoxy resin containing a minute amount of glass fiber having a diameter of about 8 μm was applied to the four sides of the substrate except for the portion to be the liquid crystal injection port. Then, two substrates with electrodes were attached to each other to prepare a liquid crystal cell.

Next, nematic liquid crystal (general-purpose TN liquid crystal material can be used, for example, ZLI series from Merck) is injected into the liquid crystal cell by a vacuum injection method, and then the injection port is sealed with a photo-curing resin, A TN liquid crystal display device was formed. Further, the respective polarizing axes were attached to the front and back surfaces of the substrates so that the respective rubbing alignment directions of the alignment films of the respective substrates coincided. The light source was placed on the lower surface of the back substrate.

Next, a chiral nematic liquid crystal display device was manufactured. Two substrates with a transparent conductive film (ITO) were prepared. Etching was performed on each substrate so that the electrode shape, the electrode line interval, and the number of electrodes corresponded to the hour / minute display, and an electrode group was formed. Next, an insulating layer was formed on the electrode surface side of each substrate.

Subsequently, a polymer solution of polyimide was applied on the insulating layer of each substrate and baked to form a polyimide film.
The film thickness was about 600Å. The surface of this polyimide film was not subjected to rubbing treatment and was left as it was after being baked, and used as a non-aligned film without rubbing.

Next, a liquid crystal cell was manufactured by the same procedure as that for a general-purpose TN liquid crystal display element. At this time, the spacer has a diameter of 4μ.
m glass fiber, and a glass fiber having a diameter of 4 μm was used in the seal. For CL-LC, T _c = 87
° C, Δn = 0.231, Δε = 16.5, viscosity η = 3
84.7 parts of nematic liquid crystal having 2 mPa · s and specific resistance of 2 × 10 ¹¹ Ω · cm, 5.1 parts of the chiral agent shown in Chemical formula 1,
Liquid crystal P was used in which 5.1 parts of the chiral agent shown in Chemical formula 2 and 5.1 parts of the chiral agent shown in Chemical formula 3 were dissolved and mixed. This liquid crystal P
Had a helical pitch of about 0.34 μm.

[0063]

[Chemical 1]

[0064]

[Chemical 2]

[0065]

[Chemical 3]

After the liquid crystal P was injected into the liquid crystal cell by the vacuum injection method, the injection port was sealed with a photo-curing resin. The injected liquid crystal P was in direct contact with the polyimide film to form a predetermined alignment state.
A black paint for matting was previously provided as a coloring layer on the back substrate surface of this liquid crystal panel.

This chiral nematic liquid crystal display device has the following optical states. In the PL state, which is one of the bistable optical states, the average direction of the orientation axis (helical axis) of the twist structure having a constant repetition pitch p is substantially perpendicular to the electrode substrate. And λ = n _AVG · p
Selective reflection occurs at the wavelength λ of.

On the other hand, in the FC state, the helical axis is oriented in a discrete direction with respect to the electrode substrate surface, and a part of the incident light is scattered but most of the light is transmitted. Therefore, the color of the colored layer provided on the back side is observed from the front side.

Then, after applying a bipolar rectangular wave pulse of 30 V with a pulse width of 500 ms to the external electrode of the chiral nematic liquid crystal display element, the voltage was cut off.
All the pixel portions were in the PL state and reflected green light. Next, when a 20 V bipolar rectangular wave pulse was applied and then the voltage was cut off, weak scattering due to the FC state was exhibited, and the background color black was visually recognized from the front side, and all the pixel portions became black.

After that, even if the voltage applied to change the optical state was cut off, the stable alignment state of the liquid crystal layer of the display section was maintained, and a sufficient contrast ratio that could be visually recognized as a display could be secured.

The display surfaces of the two liquid crystal display elements thus formed are brought into contact with each other to perform one display. In this example, a normal TN liquid crystal drive IC is used for TN
The liquid crystal display device was driven to blink the "second display" and "colon" at the digits of 10 seconds and 1 second. Moreover, the display of "hour display / minute display" was performed by the chiral nematic liquid crystal display element, and the purpose of the clock display could be achieved.

At this time, the display surfaces of the two liquid crystal panels were brought into contact with each other and mounted on a printed wiring board to form one liquid crystal module. The electrodes constituting the segments of both liquid crystal panels were arranged so that the shortest distance between them was within 20 mm in a plane parallel to the substrate surface. As a result, the power consumption of the display device as a whole can be significantly reduced as compared with the case where each liquid crystal panel is used alone.

In this example, it was necessary to manufacture each of the two liquid crystal display elements, and the step of assembling the display surfaces of the two liquid crystal display elements with high accuracy was required.

Example 2A A substrate with electrodes was prepared in the same manner as in Example 1, a predetermined electrode pattern was formed, and an insulating layer was formed on the electrode surface side of each substrate. Next, a resin solution of polyimide (LX-5800) is applied by a printing and transfer method only on the insulating layer corresponding to the first region where the TN-LC of the substrate is arranged, and this is baked to form a polyimide film. Formed. The rubbing treatment was performed in one direction so that the rubbing orientation directions were orthogonal to each other when the two substrates were arranged to face each other. This resin film has a thickness of 300Å and a pretilt angle of about 2
It was °.

Using these two substrates with electrodes, a liquid crystal cell was assembled in the same procedure as in Example 1. At this time, CL-L
At the boundary between the second area where C is arranged and the first area, a sealing material made of epoxy resin containing a small amount of glass fiber having a diameter of about 4 μm is applied in the same manner as the four sides of the substrate to form the boundary sealing part. Provided. Then, attach the two substrates,
A boundary seal portion was provided between the minute display and the second display, and two liquid crystal cells spatially separated were formed between a pair of substrates.

Next, nematic liquid crystal was injected into the first region and liquid crystal P of Example 1 was injected into the second region by a vacuum injection method. Although the liquid crystal can be injected into the two cell spaces separately, the injection ports are provided on the same side of the outer shape of the substrate, and different liquid crystal materials are immersed in the respective injection ports, and vacuum injection is performed at the same time.

After the injection of the liquid crystal material, two injection ports were sealed with a photo-curing resin to manufacture a liquid crystal panel. Furthermore, the first
The polarization axis was aligned with the rubbing direction of the alignment film on each substrate, and the two polarizing plates were attached so as to form the crossed Nicols only in the portion corresponding to the region of (1). Thus, one liquid crystal panel provided with two different types of liquid crystal layers was manufactured in one manufacturing process.

Since CL-LC does not require the presence of the alignment film in order to develop the characteristic bistability, such a manufacturing process can be used. This liquid crystal panel could be displayed by the same driving method as in Example 1. The driving voltage range is about 20 to 30 V for CL-LC, T
It was about 2-3 V by N-LC. Therefore, a good contrast ratio was obtained with low power consumption, and the productivity was good and the manufacturing cost could be significantly reduced as compared with the case where both liquid crystal panels are manufactured separately.

(Example 2B) In the same manner as in Example 1, two substrates with electrodes were prepared, an electrode group was formed, and an insulating layer was formed.
Next, polyimide (LX-580) was formed on the insulating layer of each substrate.
The resin solution of 0) was applied by a printing and transfer method, and this was baked to form a polyimide.

The film thickness of this polyimide film was 300Å. Further, a metal mask having an opening corresponding to the first region on the two substrates with electrodes was set. After rubbing the respective substrate surfaces in one direction so that the rubbing directions between the two substrates were orthogonal to each other, the metal mask was removed from the substrates. The masked portion was not subjected to rubbing treatment, only the portion of the first region was subjected to rubbing treatment, and the pretilt angle was about 2 °. Further, a liquid crystal cell and a liquid crystal panel were manufactured in the same manner as in Example 2A.

This liquid crystal panel can be driven in the same manner as in Example 2A, the driving voltage is about 20 to 30 V in CL-LC, and TN-
It was about 2 to 3 V in LC. As a display device, a good contrast ratio was obtained with low power consumption, and productivity was good and the manufacturing cost was significantly reduced compared to the case where both liquid crystal panels were manufactured separately.

(Example 2C) In the same manner as in Example 1, two substrates with electrodes having a pattern for clock display were prepared, an insulating layer was formed, and polyimide (LX-5800) was applied.
It was fired to form a polyimide film having a thickness of about 300Å. In this example, the rubbing process was not performed. An in-plane spacer and a spacer for peripheral sealing were used under the same conditions as in Example 2A.

Next, a liquid crystal material similar to that of the liquid crystal P was used, and the ratio of the liquid crystal and the chiral material was adjusted so that the helical pitch of the liquid crystal was about 16 μm. The helical pitch of the liquid crystal Q is extremely long as compared with that of CL-LC which is injected into the second region. Therefore, the twist arrangement of about 90 ° is averaged in the cell gap of 4 μm. This makes it possible to form a liquid crystal layer that is almost the same as a normal TN liquid crystal display element.

Then, the liquid crystal Q was simultaneously injected into the first region and the liquid crystal P was injected into the second region by a vacuum injection method, and then the injection port was sealed with a photo-curing resin to manufacture a liquid crystal panel. Further, the two polarizing plates were arranged so as to be in the crossed Nicols state only in the portion corresponding to the first region.

In the first region, liquid crystal molecules were vertically aligned by applying a voltage equal to or higher than the threshold value V _th , and incident light was unable to pass through the polarizing plates arranged orthogonally, resulting in black display. When the voltage was cut off, a large number of microdomains with helical axes oriented in random directions were formed at the substrate interface. A large number of the minute domains are dispersed to form a multi-domain structure. Therefore, there is a domain that looks completely bright through the polarizing plate.
There is also a domain that appears to be dark after it is extinguished, providing average brightness. Then, the contrast ratio with black when the voltage is turned on can be secured.

Thus, one liquid crystal panel provided with two different types of liquid crystal was manufactured in one manufacturing process. This liquid crystal panel could be driven in the same manner as in Example 1. The contrast ratio in the first region was 2-3. In this example, the liquid crystal material can be commonly used, the alignment film is also common in the first region and the second region, and the rubbing treatment is not required. Therefore, the manufacturing is extremely easy, and the manufacturing cost can be significantly reduced.

Example 2D Two substrates with electrodes were prepared in the same manner as in Example 2A, and an insulating layer was formed on the electrode surface side of each substrate. Next, the first of one substrate (hereinafter referred to as P ₁ )
A polyimide film having a low pretilt angle (about 2 °) was formed in the area of 2 by using LX-5800.

In the second area, the resin solution (model number: JAL
S-682-R3 manufactured by JALS Co., Ltd. was applied by a printing and transfer method, respectively, and this was baked to form a polyimide film having a high pretilt angle (about 89 °). Then, this substrate was rubbed in one direction, and this substrate was set as a back substrate.

On the other substrate (hereinafter referred to as P ₂ ) which is a front substrate, a resin solution was applied in the same manner as P ₁ to form a polyimide film, which was used without being rubbed. It should be noted that for the substrate P ₂ , a base film such as an insulating film may be used as it is and may be in contact with the liquid crystal layer.
A liquid crystal cell and a liquid crystal panel were assembled from the two substrates with electrodes in the same manner as in Example 2A.

In the liquid crystal panel of this example, C was applied to the liquid crystal contact surface formed by rubbing an alignment film having a high pretilt angle.
When L-LC was in contact, a bistable operation was obtained in a PL state close to specular reflection and an FC state showing slight scattering.

Further, the TN-LC sandwiched between the alignment films having a low pretilt angle under the low cell gap condition has a normal TN-LC.
The same operation as that of LC could be performed. Therefore, the liquid crystal panel including a plurality of liquid crystal layers exhibiting different operation modes can be manufactured by the manufacturing method in which different alignment films are separately applied in the same substrate as in this example.

The liquid crystal panel of this example also showed the same driving characteristics as in Examples 2A and 2B. Further, as compared with the case where two liquid crystal panels are manufactured separately, the productivity is good and the manufacturing cost can be significantly reduced.

Example 3 The above liquid crystal panel was used as a liquid crystal display device for a desk clock (see FIG. 5). The left side of FIG. 5 is the second area 1 where display is performed by the second liquid crystal layer.
A is the first area 1B on the right side, which is displayed by the first liquid crystal layer. In the second area 1A, in addition to the hour and minute display, the month and day display and the symbol are simultaneously displayed. In the first area 1B, only the second display, which is frequently rewritten, is displayed. As a result, a display device capable of displaying with low power consumption and suitable for battery driving was obtained.

Example 4 The above liquid crystal panel was used for the display device 30 of the oscilloscope. FIG. 6 shows the display. The display screen is divided, and the display information that is less frequently rewritten, such as the month and day or the number of the measurer, is displayed in memory by the second liquid crystal layer, and the display information (waveform data) that is frequently rewritten is displayed at the first liquid crystal layer. Configured to display.

At this time, when the measured data values and the like were transferred from the non-memory type first liquid crystal layer to the memory type second liquid crystal layer for displaying, the liquid crystal portion could be used as a memory. . For example, even when the power of the device is cut off, the display information can be read directly from the display screen. Table 2 below shows the configuration contents of each example.

[0096]

[Table 2]

(Examples 5A to 5D, 6, 7) Above Examples 2A to
The alignment film material of each of the 2D, 3 and 4 liquid crystal panels was changed to a resin material capable of forming a resin film having a soft surface hardness. Specifically, a liquid crystal panel and a liquid crystal display device were manufactured using a polyimide resin solution RN-1266 or RN-1286 manufactured by Nissan Chemical Industries, Ltd. The surface hardness of the polyimide film after baking was "B" and "3B" by the pencil test method, respectively. In this example, a good display could be obtained without the image sticking phenomenon on the display surface of the CL-LC which is a bistable liquid crystal. A technique using this specific alignment film in a chiral nematic liquid crystal display device is
The present inventors have shown in Japanese Patent Application No. 2000-402045.

Example 8 The liquid crystal panel of the present invention was used for a display device of a portable electronic device (see FIG. 12). A 63 ° twist-aligned TN-LC was used as the first liquid crystal layer, and only one polarizing plate corresponding to the TN-LC was arranged on the front substrate side.
A reflective film was provided on the inner surface of the back substrate side to provide a reflective structure. In the case of 63 ° twist orientation, Δn · d of the liquid crystal layer
Is preferably selected from the range of 0.17 to 0.26 and set.

The liquid crystal P of Example 1 was used for the second liquid crystal layer. The liquid crystal display device of this example has a display surface of 3 cm × 4 cm square, and the display surface is divided into two areas, and 3 c
CL-LC of size mx 1 cm and T of 3 cm x 3 cm
N-LC and N-LC were arranged so as to have a rectangular shape as a whole. Then, a front light having LEDs arranged on the side edges of the transparent substrate having irregularities was provided on the front substrate.

Then, the liquid crystal display device was designed such that two liquid crystal layers are used properly for display depending on the nature of the display information. Display information that is frequently rewritten is TN-LC
Is displayed, and the display information is displayed with relatively low rewriting frequency by controlling the driving device with the microcontroller so as to display with CL-LC.

Also, display information that is frequently rewritten is TN
-If the display information is displayed on the LC and there is display information to be stored, the user performs a predetermined operation on the liquid crystal display device to display CL-on the display surface of the TN-LC.
The display can be moved to the LC display surface. In this case, since the display information is stored in the CL-LC itself, the display information can be always viewed even if the liquid crystal display device is powered off.

In each of the examples described above, various light sources such as a front light type, a backlight type (direct type or edge light type), or a semi-transmissive reflection type backlight in which external light and a built-in light source are used and a liquid crystal layer. Can be selected and used in combination with. At that time, the configuration of the TN-LC used in combination with the CL-LC may be changed to a reflective type or a transmissive type to optimize it so that desired display characteristics can be obtained.

[0103]

According to the present invention, when various kinds of display information are to be displayed on a liquid crystal display device, one liquid crystal panel or liquid crystal display device achieves a predetermined display despite low power consumption. it can. Further, it is possible to provide a liquid crystal panel which is easy to manufacture and has good productivity.

Further, a plurality of liquid crystal layers having different operation modes can be manufactured in the same process as manufacturing a general passive drive type liquid crystal display device, and a liquid crystal display device with good productivity can be provided. .

[Brief description of drawings]

FIG. 1 is a partial perspective view of a liquid crystal panel of the present invention by a method of partially coating a boundary film.

FIG. 2 is a partial cross-sectional view of the liquid crystal panel of FIG.

FIG. 3 is a partial perspective view of a liquid crystal panel of the present invention by a partial coating method on a substrate surface.

FIG. 4 is a partial cross-sectional view of the liquid crystal panel of FIG.

FIG. 5 is a schematic diagram showing a display state when the liquid crystal display device of the present invention is used in a timepiece.

FIG. 6 is a schematic diagram showing a display state when the liquid crystal display device of the present invention is used in a measuring instrument.

FIG. 7 is a schematic diagram illustrating an alignment treatment process of configuration example A.

FIG. 8 is a schematic diagram illustrating an alignment treatment process of configuration example B.

FIG. 9 is a schematic diagram illustrating an alignment treatment process of configuration example C.

FIG. 10 is a schematic diagram showing an alignment treatment process of configuration example D.

FIG. 11 is a schematic diagram illustrating an alignment treatment process of configuration example E.

FIG. 12 is a schematic diagram showing a display surface of Example 8.

[Explanation of symbols] 1: Front board 2: Back substrate 1A: second area of front substrate 1B: first area of front substrate 2A: second area of back substrate 2B: First area of back substrate 3A, 3B, 4A, 4B: Boundary film (alignment film) 5: Peripheral seal 5C: Boundary seal part 6: First liquid crystal layer (twisted nematic liquid crystal layer) 7: Second liquid crystal layer (chiral nematic liquid crystal layer) 15: Drive device 20, 30: Liquid crystal display device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Noriko Suehiro             1150 Hazawa-machi, Kanagawa-ku, Yokohama-shi, Kanagawa             Asahi Glass Co., Ltd. (72) Inventor Toshihiko Suzuki             1150 Hazawa-machi, Kanagawa-ku, Yokohama-shi, Kanagawa             Asahi Glass Co., Ltd. F-term (reference) 2H089 HA33 QA16                 2H090 HC05 HC06 KA05 KA08 LA09                       LA16 MA03 MA10 MA15 MA16                       MB01

Claims (6)

[Claims] 1. A first substrate between the front substrate with electrodes and the back substrate with electrodes.
Area and a second area are provided, the first liquid crystal layer is sandwiched between the front substrate and the back substrate of the first area, and the second liquid crystal layer is sandwiched between the front substrate and the back substrate of the second area. And the electrodes are arranged so that a voltage can be independently applied to the first liquid crystal layer and the second liquid crystal layer, and only one optical state is stable in the first liquid crystal layer when no voltage is applied. A liquid crystal panel in which two or more optical states can be retained in the second liquid crystal layer that is retained and in a voltage non-application state. 2. The alignment ability generated in the first liquid crystal layer by the liquid crystal contact surface on the front substrate side and the liquid crystal contact surface on the back substrate side, and the liquid crystal contact surface on the front substrate side and the liquid crystal contact surface on the back substrate side. The liquid crystal panel according to claim 1, which has a different alignment ability from the second liquid crystal layer. 3. Alignment ability generated in the first liquid crystal layer and alignment generated in the second liquid crystal layer when the liquid crystal layer is sandwiched by using the same liquid crystal material in the first region and the second region. The liquid crystal panel according to claim 1, wherein a combination of liquid crystal contact surfaces that make the capabilities substantially equal is provided on the front substrate and the back substrate, and different liquid crystal materials are used for the first liquid crystal layer and the second liquid crystal layer. 4. The first liquid crystal layer according to claim 1, 2 or 3, wherein the first liquid crystal layer has a twist orientation of 30 to 300 °, and at least one polarizing plate is arranged corresponding to the first liquid crystal layer. LCD panel. 5. The liquid crystal panel and the driving device according to claim 1, 2, 3 or 4, and the display rewriting frequency for the first liquid crystal layer is higher than the display rewriting frequency for the second liquid crystal layer. Many liquid crystal display devices. 6. A liquid crystal contact surface having a horizontal alignment ability and a liquid crystal contact surface having a vertical alignment ability are separately formed on at least one of a front substrate with an electrode and a back substrate with an electrode, and in a state in which no voltage is applied. A method for manufacturing a liquid crystal panel, comprising forming a first liquid crystal layer having only one optical state and a second liquid crystal layer having two or more optical states when no voltage is applied.