JP2002268042A - Liquid crystal device, manufacturing method therefor and electronic instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal device excellent in characteristics and mass-productivity, suitable for an electronic instrument provided with a touch key and using a plastic substrate. SOLUTION: In this liquid crystal device, a lower substrate 21 of a pair of substrates sandwiching a liquid crystal 26 is constituted of only a plastic substrate 22. An upper substrate 13 consists of a glass substrate 14 and signal lines of a scanning line, a data line 3 and the like, a TFT connected to the signal lines, a comb-shaped pixel electrode 1 and a common electrode 11 which constitute an IPS system driving electrode and a color filter 17 are formed on the glass substrate 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device, a method of manufacturing the same, and electronic equipment, and more particularly to a structure of a liquid crystal device using a plastic substrate for at least one substrate.

[0002]

2. Description of the Related Art In recent years, with the spread of portable electronic devices such as small portable information terminals and the like, there are advantages such as lighter weight, thinner shape, easier to break, and curved surface display as compared with conventional liquid crystal display panels. There is an increasing demand for liquid crystal display panels using plastic film substrates. An example of a liquid crystal device using a plastic substrate is disclosed in, for example, Japanese Patent Laid-Open No. 6-214111.
And Japanese Patent Application Laid-Open No. 2000-267073.

In a liquid crystal display device (conventional example 1) described in JP-A-6-214111, one of a pair of substrates sandwiching liquid crystal is a glass substrate, the other is a plastic substrate,
A panel is composed of a combination of a glass substrate and a plastic substrate. In order to constitute a color liquid crystal display device, a color filter is arranged on the outer surface of the plastic substrate.

A liquid crystal display device (conventional example 2) described in Japanese Patent Application Laid-Open No. 2000-267073 also has a panel composed of a combination of a glass substrate and a plastic substrate in the same manner as described above. An object of the present invention is to provide a color liquid crystal display device using a thin film transistor (hereinafter abbreviated as a TFT) as a switching element of a pixel. A TFT and a color filter are formed on a glass substrate used as an element substrate. Then, a common electrode, an alignment film, and the like are formed on a plastic substrate used as a counter substrate.

Although the liquid crystal display devices described in these two publications are composed of a combination of a glass substrate and a plastic substrate, a device using two plastic substrates has been studied in pursuit of thinner and lighter weight. Have been. A liquid crystal display device using a plastic substrate can be used for various electronic devices, but at present, it is often used for small portable devices such as watches, calculators, electronic organizers, and the like, for example, calendar display, schedule, address book management, and the like. When switching various functions, the function can be switched by touching a part of the screen on which the desired function is displayed with a finger or a pen, or the handwriting input can be performed. There are also things. In the case of this type of liquid crystal display device for a portable device, a switch for switching functions or a touch key as an input device is mounted on a substrate serving as a display surface.

[0006]

As described above, a liquid crystal display device using a plastic substrate has many advantages such as reduction in thickness and weight, but it has various problems. I have. One of them is the problem of heat resistance and elasticity of the plastic substrate. That is, a plastic such as a methacrylate resin or a polycarbonate resin is used as a material of the plastic substrate. Generally, the glass transition temperature of these plastic materials is 150 to 200 ° C.
And the substantial heat-resistant temperature is about 120 to 150 ° C.
Heat treatment at 0 ° C. or higher cannot be applied.

Therefore, for example, in the case of the liquid crystal display device of Conventional Example 2, a common electrode made of a transparent conductive film such as indium tin oxide (hereinafter abbreviated as ITO) is provided on the plastic substrate side as the opposite substrate. Although it is necessary to form the film, general sputtering which becomes high during the formation of the ITO film cannot be used, and room temperature sputtering is indispensable. However, an ITO film formed by room-temperature sputtering is a normal IT film.
There are drawbacks such as a higher resistance value and lower reliability than the O film, and a high quality film cannot be obtained. Also, as for the alignment film formed on the common electrode, it is troublesome that a material having a low firing temperature needs to be selected.

Further, the plastic substrate has a higher coefficient of thermal expansion than the glass substrate, and greatly expands and contracts even with a slight temperature change. Further, the degree of expansion and contraction becomes more remarkable as the substrate becomes larger. For this reason, it is difficult to accurately align a plastic substrate with another substrate when bonding two substrates after a heat history in a manufacturing process for each substrate, and it is difficult to increase the size of a liquid crystal device using a plastic substrate. It was difficult. In addition, in the case of the liquid crystal display device of Conventional Example 1, not only the alignment between the substrates but also each pixel and each of R, G, and B at the time of actually bonding the plastic substrate after expansion and contraction to the external color filter. It was difficult to precisely align the dye layers.

Usually, when mass-producing a liquid crystal display device, a plurality of patterns of the liquid crystal display device are simultaneously formed on one mother glass, two mother glasses are bonded together, and a liquid crystal is injected. A manufacturing method called so-called "multiple-piece" is adopted, in which the liquid crystal display device using a plastic substrate needs to be bonded to a large-sized substrate for the above-mentioned reason. Could not be implemented. Therefore, conventionally, each device is individually manufactured from the beginning, or in the case of a combination of a glass substrate and a plastic substrate, even if it is made together, at most one plastic glass divided for each device on one mother glass is used. A method of bonding substrates has been adopted. However, these were very poor productivity methods.

In the case of a liquid crystal device provided with a touch key, when the touch key is pressed with a finger or a pen, the pressing force distorts the substrate of the liquid crystal cell therebelow, resulting in distorted display.
The cell gap may change and display unevenness may occur. As a countermeasure, these are joined via a spacer or the like for providing a gap between the liquid crystal cell and the touch key,
A gap is provided so that the liquid crystal cell and the touch key do not directly contact. However, with this configuration, the thickness of the entire liquid crystal device has been increased, which has been an obstacle to thinning the liquid crystal device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has disadvantages in that a desired characteristic cannot be obtained due to a limitation of a processing temperature in a manufacturing process and alignment between substrates is difficult. It is an object of the present invention to provide a liquid crystal device which can be manufactured without occurrence, has excellent productivity, and has a structure suitable for an electronic device having a touch key, and a method for manufacturing the same.

[0012]

In order to achieve the above object, a liquid crystal device according to the present invention comprises a pair of substrates sandwiching liquid crystal, a plurality of scanning lines and a plurality of data lines formed in a matrix. A switching element connected to the scanning line and the data line, a pixel electrode connected to the switching element, and a common electrode for generating a horizontal electric field between the pixel electrode, a liquid crystal device, One of the substrates is a plastic substrate, and a plurality of scanning lines and a plurality of data lines, a switching element, a pixel electrode, and a common electrode are provided over the other substrate.

The present inventors, when studying the means for solving the above-mentioned problems, considered whether the presence of the electrode and the alignment film on the plastic substrate side could be eliminated. As described above, even if a TFT substrate is used as the substrate on the side opposite to the plastic substrate (this substrate is referred to as the other substrate in the claims), a conventional example using a pixel electrode is a conventional example. A common electrode is required on a plastic substrate as shown in FIG. Thin Film Diode (TFD)
(Hereinafter abbreviated as a switching element) also requires an electrode on the plastic substrate side.

On the other hand, a pixel electrode on the other substrate,
If a common electrode is provided, and the liquid crystal is driven by a lateral electric field generated between the pixel electrode and the common electrode, a so-called in-plane switching (hereinafter abbreviated as IPS) driving method is adopted. Thought that it would be possible to eliminate the electrodes from the plastic substrate side. That is, a switching element, a scanning line and a data line for driving the switching element, a pixel electrode electrically connected to the switching element, and a common electrode are provided on the other substrate, and a basic substrate is provided on a plastic substrate (one substrate). Is a configuration in which nothing is provided.

According to this configuration, since there is no pattern requiring alignment on the plastic substrate in the first place, no alignment is required when the other substrate and the plastic substrate are bonded to each other. Does not hinder alignment. Therefore, the size of the liquid crystal device can be easily increased, and not only the size of each liquid crystal device can be increased, but also the manufacturing method of “multiple-piece” can be adopted at the time of manufacturing the liquid crystal display device, thereby improving mass productivity. be able to.

In the present invention, a conventional general glass substrate can be used as the material of the "other substrate". When a glass substrate is used, since the heat resistance temperature is sufficiently higher than that of a plastic substrate, a normal method can be used when forming various films such as ITO, and a highly reliable high-quality film is formed. can do.

However, the material of the "other substrate" is not limited to a glass substrate, and a plastic substrate may be used. According to the above explanation, a high-quality film with high reliability cannot be obtained by using a plastic substrate.
For example, during the manufacturing process, a switching element and an electrode are produced at a high temperature using a glass substrate, and after these switching elements and electrodes are completed, they are separated from the glass substrate and transferred to a plastic substrate. By using the method, a switching element or an electrode having the same characteristics as those directly formed on a glass substrate can be formed on a plastic substrate. By using both substrates as plastic substrates, the thickness and weight of the liquid crystal device can be further reduced.

The liquid crystal device of the present invention can be applied to both black and white and color displays, but a color filter is required for color display. Since the gist of the present invention is to provide nothing as much as possible on the plastic substrate side,
Also in this case, the color filter is desirably provided on the inner surface side of the other substrate. With this configuration, a color liquid crystal device can be easily realized.

The liquid crystal device of the present invention can be applied to any type of liquid crystal device of a transmission type, a reflection type and a transflective type. It is necessary to use a substrate with a sufficiently high. On the other hand, in the case of the reflection type, the reflection layer may be formed on the plastic substrate side or on the other substrate side, but when the reflection layer does not also serve as an electrode and is a solid reflection layer having only a reflection function, Can be formed on the plastic substrate side. In this case, since the reflective layer is formed in a solid pattern substantially equal to the size of the display area, there is no problem in alignment between the substrates.

When the reflection layer is provided on the plastic substrate side, it may be provided on the inner surface side (liquid crystal side) of the substrate by forming a metal film or the like, or may be provided on the outer surface side by external attachment or the like. . Especially when provided on the inner surface side of the substrate, since light does not pass through the substrate, it is possible to use an inexpensive plastic material with low light transmittance or a plastic material with low transmittance but good heat resistance. Become.

As described above, it is possible to eliminate the electrode on the plastic substrate side.
When an electrode of the type is provided, the alignment film on the plastic substrate side is not necessarily required. The reason is that according to the display principle of the IPS mode, the liquid crystal molecules are rotated in the plane of the substrate by the lateral electric field from the other substrate, instead of utilizing the twist of the liquid crystal molecules in the liquid crystal layer between the substrates. This is because the display is performed. This solves the conventional problem of having to select an alignment film on the plastic substrate side having low heat resistance that requires a low firing temperature. However, an alignment film may be provided on the inner surface of the plastic substrate. In this case, there are advantages that the contrast ratio can be improved and the display quality can be improved.

Further, in the liquid crystal device of the present invention, a touch key may be provided directly on the liquid crystal device. As described above, when a liquid crystal device is applied to a portable electronic device, a touch key may be attached to a front surface of a liquid crystal cell. A gap was provided between the key and the key, and this structure hindered the thinning of the liquid crystal device. On the other hand, in the liquid crystal device of the present invention, the deformation of the plastic substrate on the back side is absorbed by the deformation of the front substrate by the pressing, so that the display distortion can be reduced. In addition, the adoption of the IPS driving method reduces the influence of the cell gap change on the display.

In other words, in other words, the liquid crystal device of the present invention is a liquid crystal device having a pair of substrates sandwiching liquid crystal, and one of the pair of substrates is formed of a plastic substrate. The liquid crystal is driven by a lateral electric field generated from the other substrate.

The method for manufacturing a liquid crystal device according to the present invention is the method for manufacturing a liquid crystal device according to the present invention described above, wherein a plurality of liquid crystal devices corresponding to a plurality of liquid crystal devices are provided on a substrate having a size sufficient for the plurality of liquid crystal devices. Simultaneously forming a scanning line and a plurality of data lines, a switching element, a pixel electrode and a common electrode, and bonding a substrate and a plastic substrate having a size corresponding to the substrate via a sealing material, The method includes a step of injecting a liquid crystal between the substrate and the plastic substrate, a step of separating the plastic substrate for each liquid crystal device, and a step of separating the substrate for each liquid crystal device.

That is, by adopting the liquid crystal device having the above structure, alignment is not required at the time of bonding the substrates as described above, and the expansion and contraction of the plastic substrate does not become a problem. Since a “multiple-piece” manufacturing method can be adopted when manufacturing the device, mass productivity can be improved. Thereby, the manufacturing cost can be reduced.

An electronic apparatus according to the present invention includes the liquid crystal device according to the present invention. The provision of the liquid crystal device of the present invention makes it possible to reduce the thickness and weight of the liquid crystal display unit, which is particularly suitable for portable electronic devices.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an equivalent circuit diagram of switching elements, signal lines, and the like in a plurality of pixels arranged in a matrix forming an image display area of a liquid crystal device of this embodiment;
FIG. 2 is an enlarged plan view of one pixel of the liquid crystal device,
FIG. 3 is a cross-sectional view taken along line AA ′ of FIG. 2, and FIG. 12 is a schematic view illustrating the steps of assembling the liquid crystal device in order. In all of the following drawings, the scale of each layer and each member is different in order to make each layer and each member have a size recognizable in the drawings. The overall configuration of the liquid crystal device including the non-display area will be described later.

In the present embodiment, a plastic substrate is used for the lower substrate (one substrate) and a glass substrate is used for the upper substrate (the other substrate).
A data line and a scanning line, which are signal lines for driving the TFT, a pixel electrode connected to the TFT, and a common electrode for generating a horizontal electric field between the pixel electrode and the pixel electrode are formed. An example of the configuration will be described.
That is, a liquid crystal cell is constituted by a combination of a plastic substrate and a glass substrate, and the glass substrate side is an active matrix substrate.

As shown in FIG. 1, a plurality of pixels arranged in a matrix forming an image display area of the liquid crystal device in the present embodiment include a pixel electrode 1 and a TFT 2 for controlling the pixel electrode 1. The data line 3 formed and supplied with the image signal is electrically connected to the source of the TFT 2. The image signal S1 to be written to the data line 3,
S2,..., Sn may be supplied line-sequentially in this order, or may be supplied to a plurality of adjacent data lines 3 for each group. Further, the scanning line 4 is electrically connected to the gate of the TFT 2, and the scanning signals G1, G2,.
, Gm are applied in this order in a line-sequential manner. The pixel electrode 1 is electrically connected to the drain of the TFT 2. When the TFT 2 serving as a switching element is turned on for a predetermined period, the image signals S 1, S 2,... Write at the timing.

The image signals S1, S2,..., Sn of a predetermined level written in the liquid crystal via the pixel electrodes 1 are held for a certain period between the common electrodes described later. The liquid crystal modulates light by changing the orientation and order of the molecular assembly according to the applied voltage level, thereby enabling gray scale display. In the case of the normally white mode, the amount of transmitted light of the incident light is reduced according to the applied voltage, and in the case of the normally black mode, the amount of transmitted light of the incident light is increased according to the applied voltage. Light having a contrast according to the image signal is emitted from the liquid crystal device. Here, in order to prevent the held image signal from leaking, the pixel electrode 1
A storage capacitor 5 is added in parallel with the liquid crystal capacitor formed between the capacitor and the common electrode. The storage capacitor 5 is formed between the drain of the TFT 2 and a capacitor line 6 for supplying a constant potential via a dielectric film.

FIG. 2 is an enlarged plan view of one pixel. However, since there is no pattern on the plastic substrate side for the purpose of the present invention, the pattern on the glass substrate constituting the upper substrate is substantially It is a top view which shows the state which looked up from the bottom. In the liquid crystal display device of the present embodiment, liquid crystal capable of supporting the IPS mode is sandwiched between a pair of substrates including an upper substrate and a lower substrate. As shown in FIG. 2, the pattern configuration of the upper substrate is formed in a matrix such that a plurality of data lines 3 extending in the vertical direction in the figure and a plurality of scanning lines 4 extending in the horizontal direction in the figure cross each other. Is provided. An area surrounded by these adjacent data lines 3 and scanning lines 4 constitutes one pixel of the liquid crystal device of the present embodiment.

A semiconductor layer 8 is provided in a lower left portion of the pixel so as to cross under the scanning line 4, and a source electrode 9 branched from the data line 3 is provided in a source region on one end of the semiconductor layer 8. Are connected to pixel electrodes 1 respectively, and this portion is connected to a pixel switching T
FT2 is constituted. The pixel electrode 1 has two electrode fingers 1a extending in the vertical direction near the center and the right end of the pixel, and is formed in a comb shape. On the other hand, a comb-shaped common electrode 11 having two electrode fingers 11a extending in the vertical direction is provided at the center and the left end of the pixel.

Next, the cross-sectional structure of the pixel portion will be described. The cross-sectional structure of the TFT 2 may be a conventional general structure, and illustration and description thereof will be omitted. As shown in FIG.
On the upper substrate 13, a common electrode 11 made of a metal film such as aluminum is formed on the inner surface side (liquid crystal side) of a glass substrate 14, and, for example, R (red), G (green), B
A color filter 17 including a dye layer 15 of a different color (blue) and a light-shielding layer 16 (black matrix) for shielding light between the dye layers 15 is formed. The signal lines such as the TFT 2 and the data lines 3 and the scanning lines 4 are arranged in the region of the light shielding layer 16.

On the color filter 17, each dye layer 15
An overcoat layer 18 made of an insulating film is formed to flatten a step formed by the light-shielding layer 16 and the pixel electrode 1 and the data line 3 made of the same layer of a metal film such as aluminum are formed on the overcoat layer 18. Have been.
Then, an alignment film 19 made of polyimide or the like is formed on the entire surface of the upper substrate 13. The surface of the alignment film 19 has been subjected to a horizontal alignment process by a rubbing process or the like. However, since the IPS mode is used in the present embodiment, the alignment regulating force may be weaker than in the case of the liquid crystal driving method using a vertical electric field between the upper and lower substrates.

On the other hand, the lower substrate 21 is a plastic substrate 22
It consists only of: As a specific material of the plastic substrate 22, for example, a plastic plate or a plastic film made of a methacrylate resin, an acrylate resin, polycarbonate, polyether sulfone, triallyl cyanurate (triallyl cyanurate), or the like is used. The thickness of the plastic substrate 22 is preferably about 50 to 2000 μm.
About 00 μm is more desirable. Although illustration is omitted, in order to supplement the heat resistance, gas permeation resistance, solvent resistance, and the like of the plastic substrate 22, it is actually desirable that the surface of the plastic substrate be coated with various protective films. Further, in the present embodiment, no alignment film is formed on the lower substrate 21 side, but there is no particular problem from the display principle of the IPS mode. However, an alignment film may be formed on the inner surface of the lower substrate 21. Thereby, the contrast ratio can be improved, and the display quality may be improved.

An incident side polarizing plate 23 (polarizer) is provided on the outer surface side of the lower substrate 21, and an emission side polarizing plate 24 (analyzer) is provided on the outer surface side (observer side) of the upper substrate 13. A lighting device 25 (backlight) is provided below the lower substrate. Therefore, in the liquid crystal device of the present embodiment, light from the illumination device 25 sequentially transmits through the incident-side polarizing plate 23, the lower substrate 21, the liquid crystal 26, the upper substrate 13, and the outgoing-side polarizing plate 24, so that the observer's eyes. enter. The display principle of the liquid crystal device of the present embodiment basically only needs to be in the IPS mode. Whether the liquid crystal material has a positive or negative dielectric anisotropy is used, and the liquid crystal molecules associated therewith. Various settings such as the initial alignment direction and the direction of the transmission axis of each polarizing plate can be appropriately selected.

In manufacturing the liquid crystal device having the above structure, the upper substrate 13 can be basically manufactured by a well-known manufacturing method having a conventional general IPS type electrode. However, when performing color display, it is preferable to form a color filter on the upper substrate. Broadly speaking, a semiconductor layer 8, a scanning line 4, and a common electrode 11 are sequentially formed on a glass substrate 14, and a color filter 17 is formed thereon.
Next, after forming the overcoat layer 18, the data lines 3
Then, the pixel electrode 1 is formed, and finally, the alignment film 19 may be formed. The lower substrate 21 side is a plastic substrate 22
You just need to prepare However, when viewed through the entire assembly process, it is completely different from the conventional method. That is,
2. Description of the Related Art Conventionally, when manufacturing a liquid crystal device using a plastic substrate, a method has been adopted in which a liquid crystal device is manufactured individually for each device, or a plastic substrate divided for each device is bonded to one mother glass. I was On the other hand, according to the configuration of the present embodiment, it is possible to perform a multi-cavity process generally used in a liquid crystal device using two glass substrates. This assembling process will be described with reference to FIG.

First, as shown in FIG. 12A, a plastic substrate 31 having a work size (in this embodiment, a size sufficient to take four liquid crystal devices) and a pattern shown in FIG. After preparing the glass substrates 32 collectively formed for each panel, for example, a spacer 33 for keeping a constant interval between the two substrates is sprayed on the upper surface of the plastic substrate 31, and the glass substrate 32 is formed on the electrode forming surface of the glass substrate 32. Forms a sealing material 34 for sealing liquid crystal by screen printing or the like. Next, as shown in FIG. 12 (2), the sealing material 34 is cured in a state where the two substrates 31 and 32 are overlapped, and the two substrates 31 and 32 are bonded. next,
As shown in FIG. 12 (3), after cutting the plastic substrate 31 side with a cutter or the like, the glass substrate 32 side is scribed and chipped using a diamond glass scriber, a break machine, or the like, and the individual liquid crystal cells 35 (empty cells) are cut. ).

Thereafter, as shown in FIG. 12D, the two substrates 31 and 32 are passed through a liquid crystal injection port 37 which is an opening of a sealing material 34 of each liquid crystal cell 35 using a liquid crystal injection device 36.
The liquid crystal 26 is injected into the gap between them. Thereafter, as shown in FIG. 12 (5), the liquid crystal injection port 37 is sealed with a sealing material 38, and a polarizing plate is attached to both sides, thereby completing the liquid crystal device. Here, it has been described that the liquid crystal 26 is injected after the liquid crystal cell 35 is completely divided into four liquid crystal cells 35. However, only one direction is scribed in the vertical and horizontal directions from the substrate bonded in the work size, and a plurality of cells are formed in a strip shape. Of course, the liquid crystal may be injected in a state where the liquid crystal is connected. Finally, a lighting device, various driving substrates, and the like are mounted on the liquid crystal device and stored in a case, thereby completing a liquid crystal display device.

In the liquid crystal device of the present embodiment, FIG.
As shown in the figure, TF is provided on the upper substrate 13 (glass substrate 14) side.
T2, a data line 3 and a scanning line 4, which drive the TFT2,
While the comb-shaped pixel electrode 1 and the common electrode 11 and the color filter 17 constituting the IPS type electrode are provided, nothing is provided on the lower substrate 21 (plastic substrate 22) side, that is, on the plastic substrate 22. Since there is no pattern that requires alignment, there is no need for alignment when the two substrates 13 and 21 are bonded together, and the expansion and contraction of the plastic substrate 22 does not pose a problem. Therefore, the size of the liquid crystal device can be easily increased, and not only the size of each liquid crystal device can be increased, but also a method of manufacturing a plurality of liquid crystal devices can be adopted.
A color liquid crystal device can be manufactured by a manufacturing method with high productivity.

Further, since the TFT 2, various electrodes, signal lines, alignment films and the like are all formed on the glass substrate 14 side, high-temperature processing can be used in the process of forming the various films constituting these, and the reliability can be improved. And a high-quality film with high quality can be formed. As a result, a switching element, an electrode, a wiring, and an alignment film having excellent electric characteristics and reliability can be obtained. Further, there is no need to select a special manufacturing process or manufacturing apparatus that performs processing at room temperature.

In this way, it is easy to reduce the weight and thickness,
It is possible to easily realize a liquid crystal display device that makes use of the advantages of a plastic substrate such as not breaking and displaying a curved surface. In addition, this liquid crystal display device has
Since the PS mode is used, the advantage of the IPS mode such as a wide viewing angle can be obtained.

[Second Embodiment] Hereinafter, a second embodiment of the present invention will be described.
The embodiment will be described with reference to FIG. In the first embodiment, an example of a transmissive color liquid crystal device has been described. In the present embodiment, an example of a reflective color liquid crystal device will be described. Nevertheless, the basic configuration as a liquid crystal device, specifically, a planar pattern configuration including TFTs shown in FIG. 2, signal lines such as data lines and scanning lines, IPS type electrodes such as pixel electrodes and common electrodes, and the like. Is exactly the same as in the first embodiment. Therefore, in the present embodiment, only different portions will be described using the cross-sectional view of FIG. 4 corresponding to FIG. 3 of the first embodiment, and detailed description of common portions will be omitted. In FIG. 4, the same components as those in FIG. 3 are denoted by the same reference numerals.

As shown in FIG. 4, the liquid crystal device of the present embodiment uses a glass substrate 14 as an upper substrate 13 (the other substrate), and a TFT for pixel switching on the glass substrate 14.
2. Data line 3 which is a signal line for driving TFT2
Further, a scanning electrode 4, a pixel electrode 1 connected to the TFT 2, a common electrode 11 for generating a horizontal electric field between the pixel electrode 1, a color filter 17, and the like are formed. The configuration of the upper substrate 13 is exactly the same as in the first embodiment.

On the other hand, the structure of the lower substrate 41 is such that a reflective layer 42 made of a metal film having a high reflectivity such as aluminum or silver is formed on the entire inner surface of the plastic substrate 22, and an alignment film is formed on the reflective layer 42. 43 are formed. With this configuration, in the case of the present embodiment, external light such as natural light or illumination light incident from the upper substrate 13 side passes through the upper substrate 13 and the liquid crystal 26 and is reflected on the surface of the reflective layer 42, and then the liquid crystal 26 again. ,
The light passes through the upper substrate 13 and enters the eyes of the observer. Therefore, in order to uniformly scatter the reflected light over a certain wide angle, for example, a scattering layer made of a resin such as acrylic resin in which bead-like particles having different refractive indexes are dispersed or a resin having minute irregularities formed on the surface. May be formed on the reflective layer 42. Alternatively, by forming irregularities on the inner surface of the plastic substrate 22, irregularities may be provided on the surface of the reflective layer 42 formed thereon. In the case where the alignment film 43 is provided on the lower substrate 41, it is not necessary to have a strong alignment regulating force as in the case of the upper substrate 13.

A polarizing plate 24 is provided on the outer surface (display surface) of the upper substrate 13. The polarizing plate 24 serves both as a polarizer and an analyzer. Therefore, in the case of the present embodiment, the composition of the liquid crystal, the cell gap, and the like are adjusted so that the retardation of λ / 4 can be adjusted by turning on / off the liquid crystal. Further, a retardation plate may be provided on the outer surface of the upper substrate 13.

In the first embodiment, the plastic substrate 2
On the other hand, in the liquid crystal device of the present embodiment, the reflective layer 4 is provided on the plastic substrate 22 side.
2 and an alignment film 43 are provided. However, neither the reflective layer 42 nor the alignment film 43 need to be patterned and may be formed in a solid pattern, so that alignment with the glass substrate 14 is not necessary.
Therefore, since the expansion and contraction of the plastic substrate 22 does not cause a problem, not only the size of each liquid crystal device can be increased, but also a method of manufacturing a plurality of liquid crystal devices can be adopted. Can produce,
Since the elements, electrodes, and wirings can be formed by high-temperature treatment, the same effects as in the first embodiment, such as a liquid crystal device having excellent electrical characteristics and reliability and utilizing the advantages of a plastic substrate, can be obtained. it can.

In this embodiment, unlike the first embodiment of the transmission type, light is not transmitted inside the plastic substrate 22 because the reflection layer 42 is formed on the inner surface side of the lower substrate 41. Will be. Therefore, the first methacrylate resin, acrylate resin, polycarbonate, polyether sulfone, triallyl cyanurate, etc.
It goes without saying that the materials used in the above embodiments can be used, but plastic materials having a lower transmittance than these plastics, such as polyimide, having higher heat resistance can also be used. Thereby, a further effect that a highly reliable alignment film can be used can be obtained.

[Third Embodiment] Hereinafter, a third embodiment of the present invention will be described.
The embodiment will be described with reference to FIG. Although the example of the reflection type color liquid crystal device has been described in the second embodiment, this embodiment also shows another embodiment of the reflection type color liquid crystal device. Therefore, also in the present embodiment, FIG.
Only different portions will be described with reference to the cross-sectional view of FIG. In FIG. 5, the same reference numerals are given to the same components as those in FIGS.

As shown in FIG. 5, the liquid crystal device according to the present embodiment uses a glass substrate 14 as an upper substrate 13 (the other substrate) and a TFT for pixel switching on the glass substrate 14.
2. Data line 3 which is a signal line for driving TFT2
Further, a scanning electrode 4, a pixel electrode 1 connected to the TFT 2, a common electrode 11 for generating a horizontal electric field between the pixel electrode 1, a color filter 17, and the like are formed. The configuration of the upper substrate 13 is exactly the same as in the first and second embodiments.

The structure of the lower substrate 45 is such that the reflective layer 42 is formed on the inner surface side of the plastic substrate 22 in the second embodiment, whereas the reflective layer 46 is formed on the outer surface of the plastic substrate 22 in the present embodiment. A polarizing plate 47 is provided. The polarizing plate 47 is formed by forming a reflection layer 46 made of a metal film having a high reflectance, such as aluminum or silver, on one surface of a general polarizing plate, and is disposed so that the reflection layer 46 side is the outer surface side. I have. Also, plastic substrate 2
2, an alignment film 43 is formed on the inner surface. Therefore, in the case of the present embodiment, external light such as natural light or illumination light incident from the upper substrate 13 side is applied to the upper substrate 13, the liquid crystal 26, the lower substrate 45,
After transmitting through the polarizing plate 47 and reflecting on the surface of the reflective layer 46,
The light again passes through the polarizing plate 47, the lower substrate 45, the liquid crystal 26, and the upper substrate 13, and enters the eyes of the observer. Also in the case of the present embodiment, the second
As in the embodiment, means for uniformly scattering the reflected light over a certain angle may be added.

The liquid crystal device of the present embodiment is similar to the second embodiment in that the alignment between the plastic substrate 22 and the glass substrate 14 is unnecessary. Therefore, since the expansion and contraction of the plastic substrate 22 does not cause a problem, not only the size of each liquid crystal device can be increased, but also a method of manufacturing a plurality of liquid crystal devices can be adopted. As in the first and second embodiments, a liquid crystal device that can be produced, has excellent electrical characteristics and reliability because it can form elements, electrodes, and wirings by high-temperature treatment, and can take advantage of a plastic substrate can be obtained. The effect of can be obtained.

Generally, when a color filter is arranged on the upper substrate side and a reflective layer is arranged on the outer surface side of the lower substrate when forming a reflection type color liquid crystal device, light incident at a certain angle can be applied to the lower substrate having a certain thickness. There is a concern that double reflection and color mixing may occur due to parallax due to reciprocation inside the inside of the camera. This problem is remarkable when a normal glass substrate is used as the lower substrate. In this regard, in the case of the present embodiment, since the lower substrate 45 is the plastic substrate 22 having a thickness of at most about 50 to 250 μm, double reflection or color mixing due to parallax hardly causes a problem, and a good display screen is obtained. Can be

[Fourth Embodiment] Hereinafter, a fourth embodiment of the present invention will be described.
The embodiment will be described with reference to FIG. In this embodiment, an example of a liquid crystal device having touch keys will be described. However, the liquid crystal device according to the first embodiment is used as a basic configuration of an applied liquid crystal device. Therefore, also in this embodiment, only different portions will be described using the cross-sectional view of FIG. 6 corresponding to FIG. 3 of the first embodiment, and detailed description of common portions will be omitted. 6, the same reference numerals are given to the same components as those in FIG.

As shown in FIG. 6, the liquid crystal device according to the present embodiment uses a glass substrate 14 as an upper substrate 13 (the other substrate) and a TFT for pixel switching on the glass substrate 14.
2. Data line 3 which is a signal line for driving TFT2
Further, a scanning electrode 4, a pixel electrode 1 connected to the TFT 2, a common electrode 11 for generating a horizontal electric field between the pixel electrode 1, a color filter 17, and the like are formed. The lower substrate 21 is composed of only the plastic substrate 22. And
An incident side polarizing plate 23 (polarizer) is provided on the outer surface side of the lower substrate 21, and an emission side polarizing plate 24 (analyzer) is provided on the outer surface side (observer side) of the upper substrate 13. Is provided with a lighting device 25 (backlight).
The above configuration is exactly the same as that of the first embodiment.

In the present embodiment, the output side polarizing plate 2
A touch key 51 is arranged on the outer surface side of the touch panel 4. Although the detailed structure of the touch key 51 used here is not shown, a position detection method includes a resistance contact method, a capacitance method, and the like. In any case, a transparent electrode having a predetermined shape is formed on the inner surface. This is one in which a pair of substrates are arranged to face each other.

Also in the case of the liquid crystal device of this embodiment, the size of the liquid crystal device can be increased and a manufacturing method in which a plurality of devices can be used can be adopted. , Electrodes, and wiring can be formed, so that a liquid crystal device that is excellent in electrical characteristics and reliability and can take advantage of a plastic substrate can be obtained.
The same effect as that of the embodiment can be obtained.

Further, in the case of this embodiment, the touch key 5
The glass substrate 14 is also deformed to the extent that 1 is deformed by pressing, but the deformation is absorbed by the deformation of the plastic substrate 22, so that the gap between the two substrates is kept substantially uniform,
With the liquid crystal device having the touch keys 51, the problem of display distortion due to pressing, which has conventionally been a problem, can be reduced. That is, since there is no problem even if the touch keys 51 are directly stuck on the liquid crystal device without leaving a space, the device can be made thinner. Further, since the IPS driving method is employed, the influence of the cell gap change on the display is reduced. As a result, a liquid crystal display device suitable for a small portable device such as a timepiece, a calculator, and an electronic organizer can be provided.

In the present embodiment, an example in which the liquid crystal device of the first embodiment is provided with touch keys is shown, but the configuration of the liquid crystal device having the touch keys is not limited to this. Instead, they may be provided in the liquid crystal devices of the second and third embodiments, or may be provided in liquid crystal devices of other configurations.

[Overall Configuration of Liquid Crystal Device] The overall configuration of the liquid crystal device of the above embodiment including a non-display area will be described below. Here, the description will be made on the assumption that the upper substrate is a plastic substrate and the lower substrate is a glass substrate. The overall configuration of the liquid crystal device is, as shown in FIG.
On top, a sealing material 34 is provided along its edge,
A light-shielding film 54 as a frame is provided in parallel with the inside. In a region outside the seal member 34, a data line driving circuit 55 and an external circuit connection terminal 56 are provided along one side of the upper substrate 13, and a scanning line driving circuit 57 is provided on two sides adjacent to this one side. It is provided along. Further, on one remaining side of the upper substrate 13, a plurality of wirings 58 for connecting between the scanning line driving circuits 57 provided on both sides of the image display area are provided.

As shown in FIG. 8, the plastic substrate 22 on the side of the lower substrate 21 having substantially the same contour as the sealing material 34 shown in FIG. 7 is fixed to the upper substrate 13 by the sealing material 34. 13 and the lower substrate 21
6 is enclosed. The opening provided in the sealing material 34 shown in FIG.
Is sealed by.

[Electronic Apparatus] An example of an electronic apparatus including the liquid crystal display device of the above embodiment will be described. FIG. 9 is a perspective view showing an example of a mobile phone. In FIG. 9, reference numeral 1000 denotes a mobile phone main body, and reference numeral 1001 denotes a liquid crystal display unit using the above-described liquid crystal display device.

FIG. 10 is a perspective view showing an example of a wristwatch type electronic device. In FIG. 10, reference numeral 1100 denotes a watch main body, and reference numeral 1101 denotes a liquid crystal display section using the above-described liquid crystal display device.

FIG. 11 is a perspective view showing an example of a portable information processing device such as a word processor or a personal computer. 11, reference numeral 1200 denotes an information processing device, reference numeral 1202 denotes an input unit such as a keyboard, reference numeral 1204 denotes an information processing device main body, and reference numeral 1206 denotes a liquid crystal display unit using the above-described liquid crystal display device.

Since the electronic apparatus shown in FIGS. 9 to 11 includes the liquid crystal display section using the liquid crystal device of the above embodiment, the liquid crystal display section can be made thinner and lighter, hardly broken, and curved. It has the advantage that it can be displayed,
It is suitable for this kind of portable electronic device.

The technical scope of the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the present invention. For example, in the first embodiment, an example of a transmission type liquid crystal device,
In the third embodiment, an example of the reflection type liquid crystal device has been described.
With the function of reflecting and transmitting light at a certain rate,
The present invention can also be applied to a transflective liquid crystal device having a reflective layer called a so-called half mirror or a reflective layer in which a window for light transmission is formed in each pixel and an illuminating device.

Also, in the second and third embodiments, the reflection layer is formed on the plastic substrate side when forming the reflection type liquid crystal device. However, the configuration on the glass substrate side becomes considerably complicated. If this is acceptable, a reflective layer may also be formed on the glass substrate side on which TFTs, color filters, etc. are formed, and the plastic substrate may be used as the upper substrate (observer side). Further, in all of the above embodiments, examples of the color liquid crystal device have been described. However, it goes without saying that the present invention may be applied to a monochrome liquid crystal device having no color filter.

Although the liquid crystal device is constituted by a combination of a glass substrate and a plastic substrate in all the above embodiments, the liquid crystal device may be constituted by two plastic substrates. In this case, during the manufacturing process, a method of forming switching elements and electrodes on a glass substrate, peeling the switching elements and electrodes from the glass substrate after the completion of these switching elements and electrodes, and transferring it to a plastic substrate, is adopted. It is possible to form a switching element and an electrode having the same characteristics as those manufactured in the above. Alternatively, as long as a certain degree of deterioration in characteristics can be tolerated, elements, electrodes, and the like may be directly formed on a plastic substrate. By using both substrates as plastic substrates, it is possible to further reduce the thickness and weight of the liquid crystal device. Further, the electrode described in the above embodiment, the pattern shape of the wiring and the like, the material of various films, the specific description of the film thickness and the like are merely examples,
It can be changed as appropriate.

[0069]

As described in detail above, according to the liquid crystal device of the present invention, the alignment between the plastic substrate forming a pair of substrates and the other substrate is not required, and the expansion and contraction of the plastic substrate poses a problem. In addition, not only can individual liquid crystal devices be enlarged in size, but also a multi-cavity manufacturing method can be adopted, so that liquid crystal devices can be produced by a method with high mass productivity. Elements, electrodes, and wiring are formed by high-temperature processing. Therefore, an advantage is obtained in that a liquid crystal device having excellent electrical characteristics and reliability and utilizing the advantages of a plastic substrate can be provided. In addition, a touch key can be provided without a display problem, and a liquid crystal device particularly suitable for a portable electronic device can be realized.

[Brief description of the drawings]

FIG. 1 is an equivalent circuit diagram of a plurality of pixels forming an image display area of a liquid crystal device according to a first embodiment of the present invention.

FIG. 2 is an enlarged plan view of one pixel of the liquid crystal device.

FIG. 3 is a sectional view taken along the line A-A 'of FIG.

FIG. 4 is a cross-sectional view illustrating a liquid crystal device according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a liquid crystal device according to a third embodiment of the present invention.

FIG. 6 is a sectional view showing a liquid crystal device according to a fourth embodiment of the present invention.

FIG. 7 is a plan view illustrating an overall configuration of the liquid crystal device of the above embodiment.

FIG. 8 is a sectional view taken along line H-H ′ of FIG. 7;

FIG. 9 is a diagram illustrating an example of an electronic device using the liquid crystal device of the above embodiment.

FIG. 10 is a diagram showing another example of the electronic device.

FIG. 11 is a diagram showing still another example of the electronic device.

FIG. 12 is a schematic view showing an assembling process of the liquid crystal device in order.

[Explanation of symbols]

 Reference Signs List 1 pixel electrode 2 TFT (thin film transistor, switching element) 3 data line 4 scanning line 11 common electrode 13 upper substrate (other substrate) 14, 32 glass substrate 17 color filter 19 alignment film 21, 41, 45 lower substrate (one substrate) ) 22, 31 plastic substrate 26 liquid crystal 42, 46 reflective layer 43 orientation film 51 touch key

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/1337 G02F 1/1337 5C094 1/1339 505 1/1339 505 5G435 1/1341 1/1341 1/1343 1/1343 1/1368 1/1368 G09F 9/00 338 G09F 9/00 338 366 366A 9/30 310 9/30 310 338 338 349 349B 349D (72) Inventor Hidefumi Sakata 3-3 Yamato, Suwa City, Nagano Prefecture No. 5 Seiko Epson Corporation (72) Shohei Yoshida 3-5-3 Yamato, Suwa-shi, Nagano Prefecture Seiko Epson Corporation F-term (reference) 2H048 BB01 BB02 BB44 2H089 NA24 QA12 QA16 TA01 TA04 TA09 TA12 TA17 2H090 JB03 JC11 JC13 LA15 LA20 2H091 FA02Y FA14Z GA01 GA06 GA13 LA12 LA30 2H092 GA62 JA24 JB22 JB31 MA05 NA25 N A27 PA01 PA02 PA08 PA12 5C094 AA08 AA15 AA43 AA46 BA03 BA43 CA19 CA24 DA12 DA13 EB02 EB04 EC02 ED20 FA01 FA02 GB10 5G435 AA04 AA17 AA18 BB12 BB15 BB16 CC09 CC12 EE27 EE49 FF03 GG12 HH02H18H18H

Claims (11)

[Claims] 1. A pair of substrates sandwiching liquid crystal, a plurality of scanning lines and a plurality of data lines formed in a matrix, a switching element connected to the scanning lines and the data lines, and A liquid crystal device having a connected pixel electrode and a common electrode that generates a lateral electric field between the pixel electrode, wherein one of the pair of substrates is formed of a plastic substrate, and the other is formed of a plastic substrate. A plurality of scanning lines and a plurality of data lines, the switching element, the pixel electrode, and the common electrode. 2. The liquid crystal device according to claim 1, wherein the other substrate is made of a glass substrate. 3. The liquid crystal device according to claim 1, wherein the other substrate is made of a plastic substrate. 4. The liquid crystal device according to claim 1, wherein a color filter is provided on an inner surface of the other substrate. 5. The liquid crystal device according to claim 1, wherein a reflection layer is provided on an inner surface of said one substrate. 6. The liquid crystal device according to claim 1, wherein a reflection layer is provided on an outer surface of the one substrate. 7. The liquid crystal device according to claim 1, wherein an alignment film is provided on an inner surface of the one substrate. 8. The liquid crystal device according to claim 1, wherein a touch key is provided on an outer surface of the other substrate. 9. A liquid crystal device having a pair of substrates in which liquid crystal is sandwiched, wherein one of the pair of substrates is formed of a plastic substrate, and the liquid crystal is driven by a lateral electric field generated from the other substrate. A liquid crystal device characterized by the above-mentioned. 10. The method for manufacturing a liquid crystal device according to claim 1, wherein the plurality of scanning lines corresponding to the plurality of liquid crystal devices are formed on a substrate having a size enough to accommodate the plurality of liquid crystal devices. And simultaneously forming the plurality of data lines, the switching element, the pixel electrode and the common electrode, and bonding the substrate and a plastic substrate having a size corresponding to the substrate via a sealant; A step of injecting liquid crystal between the substrate and the plastic substrate, a step of separating the plastic substrate for each liquid crystal device, and a step of separating the substrate for each liquid crystal device. Of manufacturing a liquid crystal device. 11. An electronic apparatus comprising the liquid crystal device according to claim 1. Description: