JPH0926595A - Liquid crystal display device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To laminate GH liquid crystal cells so as to realize color display, to improve reliability in connection between an internal electrode and a driving part in a lowermost layer and to facilitate a process. SOLUTION: In this liquid crystal display device which is constituted by plurally laminating the liquid crystal cells consisting of GH liquid crystal being the mixture of dyestuff molecules and liquid crystal molecules and a transference electrode in different colors, and where the driving part controlling potential information given to the respective layers is arranged in a lower layer than the laminated part of the liquid crystal cell; the respective transference electrodes 15 of the liquid crystal cells constituting the same picture element have electrode connection parts at positions where they are not superposed one another. In the electrode 15, the superposed part 15a on the electrode connection part of another transference electrode is separately formed, and the electrode connection part and the driving part of the electrode 15 are electrically connected through the separation part 15a of another transference electrode 15 of the liquid crystal cell constituting the same picture element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device capable of color display by laminating a plurality of liquid crystal cells.

[0002]

2. Description of the Related Art In recent years, a liquid crystal display (LCD) has been used as a thin, low power consumption display device in various portable information devices such as personal computers and word processors. Of the LCDs, the one in which the display surface of the display is directly viewed is called the direct-view type. Direct-view LCDs include a transmissive type that incorporates a light source such as a fluorescent lamp on the back surface and a reflective type that uses ambient light. Of these, the former requires a backlight and is not suitable for low power consumption. This is because the backlight consumes power of 1 W or more and can be used for only 2 to 3 hours when driven by a battery. Therefore, the latter reflective type is most popular as a display for portable information equipment.

The reflection type LCD uses a light reflection plate such as an aluminum foil, and a reflection plate having a matte surface is attached to a rear glass substrate constituting the LCD. Since such a reflective LCD does not emit light, it consumes less power.
However, the conventional reflection type LCD cannot display bright paper white, and naturally cannot display bright color. This is a major technical issue in developing a reflective LCD that is comparable in image quality to a transmissive TFT-LCD.

The reflective LCD has an ECB (Electrically
Controlled Birefrigence mode, GH (Guest Hos)
t) mode, TN (Twisted Nematic) mode, etc. are used. A polarizing plate is required when using the ECB mode or the TN mode. Since the light transmittance of the polarizing plate is about 40%, the utilization efficiency of light is deteriorated.

In the case of a reflective display device, the brightness of the display device is evaluated by the reflectance. This represents what percentage of the light incident on the display is reflected. This measurement is usually performed by integrating diffuse reflected light with an integrating sphere. For example, newspaper has a reflectance of about 60%, fine paper has a reflectance of about 80%, and powders of magnesium oxide, barium sulfate, etc. have a reflectance of 99% or more. On the other hand, if there was a polarizing plate, it would be 40
% Or more reflectance cannot be expected. This causes a problem in display performance. A paper white display requires a reflectance of 60% or more.

In the GH mode which does not use a polarizing plate, the light utilization efficiency is high, and paper white display is possible. GH
When color display is performed in the mode, for example, GH liquid crystal cells of three colors of cyan, magenta, and yellow may be stacked and each cell may be driven independently.

By the way, when dot matrix display is performed on these three layers of GH liquid crystal cells, it is necessary to transmit image information pixel by pixel. However, there is a concern that the electrode structure connected to each pixel will become complicated. Usually, it is easiest to supply a signal to the internal electrodes by wiring formed on the same electrode layer, but the signal supply unit is formed by concentrating on the substrate at the lowermost layer due to process restrictions. There was a need. Therefore, for connection with the transparent electrode on the upper part, an electrode connection is formed by screen printing conductive paste after opening a through hole, or a through hole is opened every time a laminated film is deposited, and the connection portion is formed by a copper plating method. A method of connecting with grown columns is conceivable.

However, this type of method has various problems to be solved in the process. That is, the diameter of the through hole for connection cannot be increased so much due to the aperture ratio, and therefore, even if a conductive paste is printed by screen printing on a groove having a large aspect ratio, a good column cannot be obtained.
Similarly, electroplating a groove with a large aspect ratio does not produce a good column. Further, the method of opening the through holes for each stack and connecting the connecting portions by the pillars grown by the copper plating method has many steps and is troublesome.

Further, the thinner or plating solution used in the paste may penetrate into the transparent electrode layer while passing through various processes such as cleaning, thermosetting and PEP processes, which may cause problems such as alteration. is expected.

[0010]

As described above, the conventional GH
In a liquid crystal display device in which liquid crystal cells are stacked to perform color display, there is a problem in that it is difficult to connect the internal electrode (transparent electrode) and the drive unit in the lowermost layer.

The present invention has been made in consideration of the above circumstances, and an object thereof is to enable color display by stacking GH liquid crystal cells, and to form internal electrodes and a drive unit of the lowermost layer. It is an object of the present invention to provide a liquid crystal display device and a manufacturing method thereof, which can improve reliability in connection of the device and facilitate the process.

[0012]

[Means for Solving the Problems]

(Summary) In order to solve the above problems, the present invention employs the following configuration. That is, according to the present invention, a plurality of liquid crystal cells each composed of a guest-host liquid crystal, which is a mixture of dye molecules and liquid crystal molecules, and a transparent electrode are laminated in different colors, and a driving unit for controlling potential information applied to each layer is formed from a laminated portion of liquid crystal cells. In the liquid crystal display device arranged in the lower layer, the transparent electrodes of the liquid crystal cells forming the same pixel have electrode connecting portions at positions that do not overlap each other, and each transparent electrode is connected to another transparent electrode. The part that overlaps the part is formed separately,
It is characterized in that the electrode connecting portion of the transparent electrode and the driving portion are electrically connected to each other through a separating portion of another transparent electrode of the liquid crystal cell forming the same pixel.

The preferred embodiments of the present invention are as follows. (1) The liquid crystal cell has a laminated structure in which the guest-host liquid crystal is enclosed in microcapsules to form a film, and one transparent electrode and one microcapsule film are used as one unit, and a plurality of units are directly laminated. That (2) Corresponding to the electrode connecting portion of the laminated transparent electrodes, through holes are provided from the transparent electrode to the lower drive portion, and each through hole is filled with a conductive material. (3) Corresponding to the electrode connecting portions of the laminated transparent electrodes, press-fitting the electrically conductive thin wires or metal whiskers between the transparent electrodes and between the transparent electrodes and the driving portion of the lower layer, and by the electrically conductive thin wires or the metal whiskers. To make an electrical connection between the transparent electrode and the underlying drive section.

According to the present invention, in the method of manufacturing a liquid crystal display device having the above-mentioned structure, each transparent electrode of the liquid crystal cell forming the same pixel is formed with an electrode connecting portion at a position not overlapping with another transparent electrode, and A portion of the other transparent electrode that overlaps with the electrode connecting portion is formed separately, and after completion of the laminated structure of the liquid crystal cell, the electrode connecting portion of the transparent electrode and the driving portion are formed in the same pixel. It is characterized in that it is electrically connected through a separate portion of another transparent electrode. (Function) According to the present invention, in each transparent electrode of the liquid crystal cells forming the same pixel, a portion corresponding to an electrical connection portion of another transparent electrode is formed separately, so that the transparent electrode and the drive portion of the lower layer are formed. Will be connected via the separate part of the other transparent electrode, which increases the reliability of the connection. That is, in the connection between the upper layer side transparent electrode and the driving section, the lower layer side transparent electrode separation section is interposed as a kind of relay point, whereby the reliability of the connection can be improved.

In particular, through holes are provided from the transparent electrode to the lower drive section, and each through hole is filled with a conductive material, or electrically conductive thin wires or metal whiskers are provided between the transparent electrodes and between the transparent electrode and the lower drive section. By press-fitting, it is possible to simplify the process without modifying the transparent electrode or patterning the guest-host liquid crystal that occurs in the process as described above, and the reliability as a display device is improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the embodiments, the basic principle of the present invention will be described. The applicant of the present invention is G
GH microcapsules using a material that can be made into a thin film by encapsulating H liquid crystal in microcapsules with a diameter not larger than the cell gap, making it available for coating on a glass substrate, and evaporating the solvent of this paste. It has already been proposed to use a film (Japanese Patent Application No. 7-56).
086).

By using this material, the reflective electrode 13 is formed on the glass substrate 11 as shown in FIG.
Further, a GH liquid crystal layer 14 and a transparent electrode (ITO, tin oxide, etc.) 15 can be alternately laminated thereon.
The transparent electrodes 15 stacked alternately are formed on the glass substrate 11 by TF.
To electrically connect to T (not shown) or the like, a method of forming a through hole and screen-printing a conductive paste, or a pillar 19 grown by an electroplating method, for example, a connecting method using a copper-plated pillar is proposed. Has been done.

However, even with such a structure, as described above, the pillar is formed in the groove having a large aspect ratio, and a good pillar cannot be obtained. Further, in the method of connecting through the through hole for each stack and connecting the connection portion by the pillar grown by the copper plating method, the number of steps is large and the process is troublesome. In addition, it is expected that the thinner or plating solution used in the paste will penetrate into the transparent electrode layer while passing through the steps of cleaning, thermosetting, PEP, etc., causing problems such as alteration.

Although the present invention solves this problem, it is needless to say that the present invention can be applied not only to the one using the GH microcapsule film as described above but also to the laminated structure of a normal GH liquid crystal cell. .

The details of the present invention will be described below with reference to the embodiments shown in the drawings. (Embodiment 1) FIG. 1 shows a schematic configuration of a liquid crystal display device according to a first embodiment of the present invention. (A) is a perspective view and (b) is a sectional view.

In the figure, reference numeral 11 denotes a glass substrate, on which a plurality of TFTs 12 as a driving unit and further signal lines and scanning lines not shown are formed.
A reflecting plate 13 made of aluminum is arranged on the glass substrate 11 with an insulating film interposed therebetween. This reflector 13 constitutes a pixel electrode. Further, a yellow liquid crystal layer 14a, a transparent electrode layer (pixel electrode) 15, a magenta liquid crystal layer 14b, a transparent electrode layer (pixel electrode) 15, and a cyan liquid crystal layer 14c are sequentially laminated on the reflection plate 13.

The liquid crystal layers 14a to 14c are formed by printing a paste containing microcapsules enclosing guest-host liquid crystals containing dye molecules of respective colors (yellow, magenta, cyan) and evaporating the solvent in the paste. Formed by. The transparent electrode layer 15 is formed by sputtering a transparent conductive material and then patterning it by photolithography and etching. The order of stacking the liquid crystal layers 14a to 14c is not limited to the above, and may be changed as appropriate.

Further, a glass substrate having a transparent counter electrode 16 is arranged on the cyan liquid crystal layer 14c.
The TFTs are electrically connected to the reflection plate 13 or the transparent electrode layer 15 by a method described later.

In the liquid crystal display device having the above structure, the liquid crystal layers 14a to 14c and the transparent electrode layer 15 do not have active elements and wirings which are non-display areas, so that the aperture ratio is wide and the transparent electrode layer is formed. Since it is formed of a thin film and no glass substrate is used, the light utilization efficiency is high.

The entire circuit configuration is the same as that of a general liquid crystal display device, and as shown in FIG. 2, a plurality of signal lines 17 and a plurality of scanning lines 18 are arranged so as to be orthogonal to each other. The TFT 1 is provided at each intersection of the signal line 17 and the scanning line 18.
A liquid crystal cell is connected via 2. However, FIG. 2 shows only one layer of the liquid crystal cell portion, and in fact, three layers are laminated so that the same pixel shares a scanning line.

When performing color display with this liquid crystal display device, the voltage applied to the four electrodes sandwiching each liquid crystal layer is predetermined by an arithmetic circuit. For example, when displaying "white", a voltage is applied as shown in FIG. In the figure, G means GND, which is a reference potential. V is a potential with respect to GND, and is a potential that can saturate T in a high state to some extent in the VT (voltage-transmittance) characteristic. Note that the voltage application is shown in two ways because it is necessary to apply an AC waveform to the liquid crystal layer. In the case of the guest-host liquid crystal, when displaying "white", it is necessary to stand the liquid crystal molecules and the dye molecules in the direction perpendicular to the electrode surface as much as possible for the sake of transmitting light, and therefore, it is shown in FIG. Voltage is applied.

On the other hand, when "black" is displayed,
In order to absorb light, it is necessary to orient the liquid crystal molecules and dye molecules in all directions as much as possible. In the liquid crystal display device of the present invention, the liquid crystal molecules are aligned such that the liquid crystal molecules are dispersed in all directions in the absence of an electric field. Therefore, "black"
When is displayed, a voltage is applied as shown in FIG.

When the primary color "red" is displayed, as shown in FIG. 3B, the magenta liquid crystal layer 14b and the yellow liquid crystal layer 14a absorb light, and the cyan liquid crystal layer 1
4c transmits light. When displaying "green", as shown in FIG. 3C, the cyan liquid crystal layer 14c and the yellow liquid crystal layer 14a absorb light, and the magenta liquid crystal layer 14b transmits light. To display "blue",
As shown in (d), the cyan liquid crystal layer 14c and the magenta liquid crystal layer 14b absorb light, and the yellow liquid crystal layer 14a transmits light.

When the complementary color "cyan" is displayed, the cyan liquid crystal layer 14c absorbs the light and the magenta liquid crystal layer 14b and the yellow liquid crystal layer 14a transmit the light as shown in FIG. 3 (f). Let When displaying "magenta", as shown in FIG. 3G, the magenta liquid crystal layer 14b is displayed.
To absorb light, and the cyan liquid crystal layer 14c and the yellow liquid crystal layer 14a transmit light. When displaying "yellow", the yellow liquid crystal layer 14a is displayed as shown in FIG.
To absorb light, and the cyan liquid crystal layer 14c and the magenta liquid crystal layer 14b transmit light.

In this way, the basic eight color display can be performed. In this case, the potentials applied to the electrodes may be V and G. On the other hand, when performing halftone display, so-called frame rate control (FRC) is used,
A dither method using a plurality of pixels, that is, an area gradation method may be used. Alternatively, as shown in FIG. 4, gradation may be displayed by controlling the transmittance with a voltage. For example, when a voltage is applied as shown in FIG. 4A, the cyan liquid crystal layer 14c is in a transmissive state, and the magenta liquid crystal layer 14b and the yellow liquid crystal layer 14a are in a semi-transmissive state. In such a case, it is possible to display a pink color. Further, when displaying light cyan, a voltage is applied as shown in FIG. In the case of such halftone display, it is necessary to set the range of the potential applied to each electrode to −V to G to + V.

Next, the specific structure of the liquid crystal display device of the present invention will be described. FIG. 5 is a perspective exploded view showing a region corresponding to one pixel of the liquid crystal display device of the present embodiment. One scanning line 18 is formed on the glass substrate 11, and three TFTs 12 are formed on the scanning line 18 at intervals. This is because there are three liquid crystal capacitors of cyan, magenta and yellow in one pixel. Further, three signal lines 17 are formed so as to be in contact with the respective TFTs 12 in a direction orthogonal to the scanning lines 18. Each TFT 12 is electrically connected to the reflection plate 13 or the transparent electrode layer 15 by a conductive paste, a metal whisker, or the like as described later. Then, the information sent to each signal line 17 is transmitted through the TFT 12 to the reflection plate (pixel electrode) 13
And to the transparent electrode (pixel electrode) 15.

In FIG. 5, the storage capacity (Cs)
Although not shown, Cs is actually connected in parallel with the liquid crystal capacitance of one pixel. That is, the common wiring for Cs is arranged in parallel with each scanning line 18, and Cs is formed between the common wiring for Cs, the signal line 18, and "a certain metal electrode" in each pixel. This "certain metal electrode" is connected to the pixel electrode in the same manner as the TFT connection. Since there are three liquid crystal capacitors for one pixel, it is necessary to provide three Cs for one pixel.

Next, a method of manufacturing the TFT array substrate shown in FIG. 5 will be described. First, a resin thin film of several microns is deposited on the glass substrate 11 by a spin coating method or the like. Then, a thin film of silicon oxide or silicon nitride is applied to 100 to 200
Then, a single substance or alloy of a conductive substance such as molybdenum, tantalum, tungsten, titanium, aluminum, chromium, copper, or a laminated film is deposited. These materials are patterned by the so-called lithography or photoengravation process (PEP), and TF
A gate of T and a gate line are formed.

Then, a thin film of silicon oxide or silicon nitride is again deposited to a thickness of 200 to 400 nm to form a gate insulating film. Further, an i-type a-Si: H layer is formed in a thickness of 10 to 400 n.
m. A thin film of silicon oxide or silicon nitride as an etching stopper layer may be deposited thereon to a thickness of 100 to 200 nm and patterned by PEP. After that, an n ⁺ -type a-Si: H layer is deposited in a thickness of 10 to 100 nm for the source / drain contact of the TFT. Here, the i-type a-Si: H layer and the n ⁺ -type a-Si: H layer, which are the channels of the TFT, are patterned by PEP.

Then, a single substance or an alloy or a laminated film of aluminum, titanium, molybdenum, tantalum, tungsten, chromium or the like is deposited as a conductive substance to be the source / drain electrodes and the signal line. This is made into a desired pattern by PEP. After that, the n ⁺ type a-Si: H layer between the source and drain of the TFT is removed to complete the TFT.

An insulating film 13 such as a silicon oxide thin film, a silicon nitride thin film, a polyimide, a polycarbonate, an acrylic resin, a fluorine resin, a polyester resin, an epoxy resin, or a silicone resin is further formed on the TFT by 0.1 to 0.1.
Deposit 3 μm. After the deposition, the surface is flattened by CMP (Chemical Mechanical Polishing).

Then, a reflection plate (pixel electrode) 13 is formed on this.
A metal such as aluminum, chromium, molybdenum, or tungsten is deposited to a thickness of 100 to 400 nm. In order to bring the reflection characteristic of the reflection plate 13 close to perfect diffusion, it is necessary to make the metal surface uneven. As a method for making unevenness, it is possible to make unevenness by PEP, a pressing method such as embossing, a method of roughening the surface with a chemical, or a method of rubbing with a file to roughen the surface.

Further, powder such as magnesium oxide or barium sulfide having a perfect diffusion characteristic may be deposited on the conductive material. After that, the yellow guest host (G
H) Apply pasty microcapsules containing liquid crystal. Then, the solvent or the like in the paste is volatilized or the microcapsules are cured. This is the first
GH microcapsule film 15. All such GH microcapsule films have a thickness of 5 to 15 μm.

Here, again, flattening is performed by CMP, and a transparent electrode (pixel electrode) 15 is deposited by 10 to 100 nm and patterned. By repeating the above-described steps the desired number of times of lamination, a laminated substrate as shown in FIG. 6A is completed. However, the second layer is a paste microcapsule containing magenta GH liquid crystal, and the third layer is a paste microcapsule containing cyan GH liquid crystal.

In this embodiment, cyan, magenta,
Although the three-layer structure of yellow has been described, a four-layer structure in which a black opaque GH microcapsule film is added may be used. This is for displaying a brighter black color.

Since the laminated film is completed through the above steps, the method for connecting the internal display electrodes will be described next. As described above, the drive and display signals are supplied from the wiring below the guest-host liquid crystal layer in FIG. 6A, so it is necessary to make internal connection.

As a method, first, the laminated film is annealed,
Improves the stability of the laminated film. After that, the ultrafine needles coated with a highly viscous conductive paste are connected to the transparent electrodes 1 of the laminated substrate of FIG.
By penetrating the FT electrode), the conductive paste 21 is left as shown in FIG. 6B, and electrical connection is made through the remaining conductive paste 21. When the filling using the viscosity of the conductive paste 21 is difficult, it is possible to fill the paste 21 into a syringe or the like and connect the paste 21 while pushing the paste 21 out. The connection using such a needle may be made once, but it is practical to make a connection all at once at the same time.

Here, in the connection with the lower layer wiring, it is necessary to separate the transparent electrode portion and the non-corresponding connecting portion which are through-connected from each other. As a simple method, as shown in FIG. 7 or 8, a method of changing the lead-out electrode pattern shape of the through connection part in correspondence with each connection layer can be considered.

In FIG. 7, electrode connecting portions are provided at positions where they do not overlap each other on one side of a rectangle of each transparent electrode 15 of the liquid crystal cells forming the same pixel, and each transparent electrode connects to another transparent electrode. The part 15a overlapping the part is formed separately. Then, the electrode connecting portion of the transparent electrode and the driving portion are electrically connected to each other via the other transparent electrode separating portion 15a of the liquid crystal cell constituting the same pixel. The same applies to the case of FIG. 8, but in this case, the electrode connection portion and the separation portion 15a are provided at the rectangular corners.

As another method of the through connection, as shown in FIG. 6 (c), metal whiskers 22 such as tungsten or fine metal wires aligned in one direction are arranged on the corresponding connection portion and pressure is applied to insulate the surface. A method is also conceivable in which the transparent electrodes between the laminated films can be connected by penetrating the film. Although it is a pressurizing time, a method of connecting by applying pressure after completion of stacking of all layers and a method of connecting by pressurizing while confirming continuity every stacking can be considered. The above-mentioned connection method is also effective as a repair means when a connection failure occurs.

Further, as shown in FIG. 9A, a stretchable film in which metal whiskers or metal fine wires having a length equivalent to the thickness of the laminated substrates are arranged in the film thickness direction is prepared. As shown in (b), it is also conceivable to carry out a pressure connection in a PEP process or the like after attaching to the laminated guest host substrate, patterning leaving only the corresponding connection portion.

In FIG. 1, the reflective electrode 13 and the two transparent electrodes 15 are connected to the TFT 12, and the other one of the transparent electrodes is used as the counter electrode (common electrode) 16, but FIG.
Then, the reflective electrode 13 is used as a common electrode, and the three transparent electrodes 15 are connected to the TFT 12. Whether the uppermost layer of the transparent electrodes or the reflective electrode is used as the common electrode may be appropriately selected according to the use. On the other hand, FIGS.
As shown in FIG. 7, by connecting the TFT to each of the four display electrodes, it is possible to set fine potentials that cannot be performed with the common electrode.

As described above, according to this embodiment, in each of the transparent electrodes 15 of the liquid crystal cells forming the same pixel, a portion corresponding to an electrical connection portion of another transparent electrode 15 is formed separately. A through hole is provided from the transparent electrode 15 to the lower drive section, and each through hole is filled with a conductive paste, or an electrically conductive thin wire or a metal whisker is provided between the transparent electrodes 15 and between the transparent electrode 15 and the lower drive section. I try to press fit. Therefore, the separation portion 15a of the other transparent electrode 15 serves as a relay point, and the reliability of the connection between the transparent electrode 15 and the lower drive portion can be improved.

Further, the conductive paste 21 for the above through holes
The filling of the electrode or the press-fitting of the electrically conductive thin wire or the metal whisker 22 does not cause the alteration of the transparent electrode 15 which occurs in the process, and it is not necessary to pattern the guest-host liquid crystal. Therefore, the process can be simplified, and the reliability of the display device is further improved. Further, since it is not necessary to stack a plurality of glass substrates as in the conventional case, it is possible to improve the light utilization efficiency. (Embodiment 2) FIGS. 10A and 10B show a main structure of a liquid crystal display device according to a second embodiment of the present invention. FIG. 10A shows a laminated substrate structure, and FIG. 10B shows how whiskers are pressed. There is.

In this embodiment, the transparent electrode 1 is formed on the glass substrate.
5 is laminated, and the GH liquid crystal layer 14 is inserted between the substrates. Then, after forming the laminated body or for each laminated body, the transparent electrode 15 and the TFT in the lower layer are electrically connected to each other by press-fitting the whisker as in the first embodiment. Note that FIG. 10B shows a state in which whiskers are press-fitted for each stack.

Even with such a structure, it is of course possible to obtain the same effect as that of the first embodiment. Note that the present invention is not limited to the above embodiments. In the embodiment, the connection method in the laminated substrate is described by the thin film process using the oxide film or the resin material. However, a means for forming a microlens in the insulating film between the substrate and the laminated film which is the base of the thin film process. The metal thin film is formed on both sides of the perforated glass substrate created by the ion exchange method, which is one of the
It is possible to use a substrate in which through holes can be formed by electrically connecting the front and back surfaces in an EP process or the like. Here, when the transparent electrodes are formed on both sides of the surface of the glass substrate, it is possible to form the double-sided electrodes by collective exposure by simultaneous double-sided exposure and simultaneous double-sided etching. In a collectively molded double-sided electrode substrate, a method of forming a laminated film on both of the display substrates and electrically connecting the both film-forming substrates is also conceivable.

Further, it is not preferable that the guest-host liquid crystal is in contact with the bonded surface because various contaminations are expected. Therefore, it is desirable that the connection surface is covered with the insulating film except for the connection terminals. Therefore, a method of covering the connection surfaces with a glass substrate or an insulating material similar thereto is negative in terms of light utilization efficiency, but is advantageous as an element forming method. The transparent electrode is formed by patterning the corresponding connecting portion and the non-connecting portion in the same manner as in FIG. 8 and FIG. 7, and by alternately interposing the glass through-hole metal and the transparent electrode and the conductive material for inter-substrate connection, Can be connected to.

On the other hand, instead of the perforated glass substrate, a porous glass substrate is used, and a conductive paste is screen-printed, or the insulating portion is masked and then the front and back surfaces of the substrate are deposited by a vapor deposition method, an ion doping method, an electroplating method, or the like. It is also possible to use a method for making the electrical connection. Substrates that have electrical connections on the front and back with appropriate intervals require internal connections between the substrates again after the display electrodes are formed.However, in a simple matrix type substrate in which no switch element is formed in the lower layer of the substrate, signal Since connection for supply can be made from one direction without forming on the front and back surfaces of the substrate, connection of the signal supply wiring can be facilitated and the number of connection wiring with the outside can be halved.

In the same ion exchange method, even if the glass substrate is not completely perforated, as shown in FIG. 10, by weakening the glass on the corresponding connection portion, the multilayer glass substrate of the guest-host liquid crystal can be formed. It is also possible to connect through.

Since this device is composed of a laminated film formed by a thin film process, the smoothness of the transparent electrode on the display surface is deteriorated. Therefore, diffused reflection of incident light occurs, resulting in a decrease in light utilization efficiency. Therefore, by forming the reflective electrode formed on the glass substrate side on the final laminated electrode side of the laminated film and allowing light to enter from the transparent substrate side that is the base, it is possible to prevent irregular reflection of incident light. Inversely incident light is
As it goes to the lower layer, the unevenness of the transparent electrode increases,
It is possible to improve the viewing angle characteristics.

[0056]

As described in detail above, according to the present invention, G
The transparent electrode pattern is devised in the structure in which H liquid crystal cells are laminated, and the through hole is filled with a conductive material, or an electrically conductive thin wire or a metal whisker is pressed into the transparent electrode pattern, so that the electrical connection between the transparent electrode and the lower drive section is reduced. Connection can be made. Therefore, it is possible to realize a liquid crystal display device capable of performing color display by stacking GH liquid crystal cells, improving reliability in connection between the internal electrodes and the drive unit in the lowermost layer, and facilitating the process. Becomes

[Brief description of drawings]

FIG. 1 is a perspective view and a sectional view showing a schematic configuration of a liquid crystal display device according to a first embodiment.

FIG. 2 is a circuit configuration diagram according to the first embodiment.

FIG. 3 is a potential configuration diagram in the first embodiment.

FIG. 4 is a potential configuration diagram in the first embodiment.

FIG. 5 is an exploded perspective view showing a region for one pixel.

FIG. 6 is a diagram showing a configuration of a laminated substrate and electrode connection portions using GH microcapsules.

FIG. 7 is a diagram showing an example of a pixel display portion pattern.

FIG. 8 is a diagram showing another example of a pixel display portion pattern.

FIG. 9 is a diagram showing a connection method using whiskers.

FIG. 10 is a diagram showing a second embodiment.

FIG. 11 is a diagram showing an example of a liquid crystal display using a GH microcapsule film.

[Explanation of symbols]

 11 ... Glass substrate 12 ... TFT (driving part) 13 ... Reflecting electrode 14 ... GH liquid crystal layer 15 ... Transparent electrode 16 ... Counter electrode (transparent electrode) 17 ... Signal line 18 ... Scanning line 21 ... Conductive paste 22 ... Metal whiskers

Claims (4)

[Claims] 1. A plurality of liquid crystal cells each composed of a guest-host liquid crystal, which is a mixture of dye molecules and liquid crystal molecules, and a transparent electrode are laminated in different colors, and a driving unit for controlling potential information applied to each layer is formed from a laminated portion of liquid crystal cells. In the liquid crystal display device arranged in the lower layer as well, the transparent electrodes of the liquid crystal cells forming the same pixel have electrode connection portions at positions that do not overlap each other, and each transparent electrode is connected to another transparent electrode. The portion overlapping the portion is formed separately, and the electrode connecting portion of the transparent electrode and the driving portion are electrically connected via the other transparent electrode separating portion of the liquid crystal cell forming the same pixel. A liquid crystal display device characterized by the above. 2. A laminated structure of the liquid crystal cell, wherein guest-host liquid crystal is enclosed in microcapsules to form a film,
2. The liquid crystal display device according to claim 1, wherein one transparent electrode and one microcapsule film are used as one unit, and a plurality of units are directly laminated. 3. An electrically conductive thin wire or a metal whisker is press-fitted between the transparent electrodes and between the transparent electrodes and the driving portion of the lower layer corresponding to the electrode connecting portion of the laminated transparent electrodes, and the electrically conductive thin wire or 2. The metal whiskers electrically connect the transparent electrode and the lower drive section to each other.
The liquid crystal display device as described in the above. 4. A liquid crystal cell composed of a guest-host liquid crystal, which is a mixture of dye molecules and liquid crystal molecules, and a plurality of liquid crystal cells composed of transparent electrodes are laminated in different colors, and a driving unit for controlling potential information applied to each layer is formed from the laminated portion of the liquid crystal cells. In the method for manufacturing a liquid crystal display device arranged in the lower layer as well, in each transparent electrode of the liquid crystal cell forming the same pixel, an electrode connection portion is formed at a position not overlapping with other transparent electrodes,
A portion of the transparent electrode that overlaps with the electrode connection portion of another transparent electrode is formed separately, and after completion of the laminated structure of the liquid crystal cell, the electrode connection portion of the transparent electrode and the driving portion form a liquid crystal cell that constitutes the same pixel. A method for manufacturing a liquid crystal display device, characterized in that the liquid crystal display device is electrically connected via another transparent electrode separation part.