JP2001147427A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a reflection type liquid crystal display device which has a wide selecting range for selecting the material of a reflection electrode and a structure difficult to exert an influence on alignment of liquid crystals and can be easily manufactured without need of a counter BM and consideration for reduction of a reflection area due to simplification of manufacturing stage and positioning accuracy to a counter substrate. SOLUTION: In the liquid crystal display device having the liquid crystal interposed between a pair of substrates, a pixel electrode consisting of a transparent conductive film disposed on one substrate in a matrix form and a semiconductor element connected to the pixel electrode, one substrate of the pair of substrates has transparency and an insulating property and the other substrate has a common electrode provided thereon and consisting of a reflection layer and a transparent conductive film. The present invention is characterized in that the reflection layer, the transparent conductive film and the common electrode are separated from one another and the reflection layer is provided on the side of the counter substrate. The reflection layer is specified to be a layer of a medium consisting of a single body or laminated structure of used material and having >=30% reflectivity in air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type and a transflective type liquid crystal display device.

[0002]

2. Description of the Related Art Active matrix liquid crystal display devices using semiconductor elements are used as direct-view display devices such as mobile computers, video cameras, digital cameras, mobile phones, head-mounted displays, and lenses such as front and rear projectors. Development is actively being conducted as a projection type display device for the purpose of enlarged display by the optical system described above.

[0003] These are classified into a reflective display device that reflects external light for display, a transmissive display device that displays by transmitting light from a light source such as a backlight or a metal halide, and a transflective display device that has characteristics of both. Is done.

[0004] The reflective display device is advantageous for a portable device because it does not require a backlight and can achieve low power consumption. Furthermore, when viewing the display under sunlight, it is easier to see than the backlight.

On the other hand, there are drawbacks in that it cannot be used because it cannot be seen in a dark place, that it is difficult to obtain a bright display because of the use of external light, and that it is difficult to increase the contrast.

[0006] For this reason, a transflective display device has been designed so that it can be used even in a dark place. However, also in this case, the contrast and brightness are inferior to those of the reflection type, and the display is more severe.

A conventional reflection type active matrix liquid crystal display device will be described below. Here, a pixel electrode that has a reflective action and utilizes this characteristic is referred to as a reflective pixel electrode.

FIG. 1A shows a conventional example of a single-polarizer type direct-view type active matrix reflective liquid crystal display device in which a reflective pixel electrode has a mirror surface.

A counter substrate comprising a color filter layer 101, a black matrix (BM) 102 and a common electrode 103, and a semiconductor element 1 such as a thin film transistor (TFT)
There is an element substrate on which the active matrix circuit formed by the element 04 is formed.

A liquid crystal 105 is injected between the two substrates, and the electric field of the common electrode 103 and the reflective pixel electrode 106 is controlled to perform electro-optic modulation. In this case, in order to align the liquid crystal 105, the alignment film 10 is provided on both electrodes 103 and 106.
7 is formed, and an alignment process such as rubbing is performed.

Thereafter, a polarizing plate 110 for controlling the amount of transmitted light in combination with the liquid crystal 105, a phase difference plate 109, a scattering plate 108 and the like are also attached to improve the viewing angle and prevent reflection.

In this specification, a polarizing plate, a scattering plate, a retardation plate,
The expression "plate" is used at the end of the expression such as λ / 4 plate, but these are usually called conventionally because they often have the form of a film. However, in the present specification, these do not necessarily have to be plate-shaped. Here, the polarizing plate is defined as a polarizing function, the scattering plate is defined as a forward scattering function, and the retardation plate and the λ / 4 plate are defined as generic names of those having a function of modulating light.

In a direct-view type liquid crystal display device employing the specular reflection pixel electrode 106, it is necessary to scatter light within an arbitrary field of view so as not to affect adjacent pixels in order to make white more white. This is realized by the scattering plate 108 and the like.

A reflector for reflecting external light is a pixel electrode 1.
06 is formed on the element substrate. Since it is formed on the data line, the gate line, the TFT portion, and the capacitor forming portion, an electrode area ratio of about 90% can be obtained in the pixel region.

Further, a reflector 10 is provided on the semiconductor element 104.
7, the irradiation amount of light to this semiconductor layer is reduced directly or indirectly. Accordingly, there is an effect that light leakage in which the off current increases can be prevented. This is particularly effective for a projector that emits light from a strong light source.

In the above-described structure, a normally white mode, in which a black display is applied when a voltage is applied to the liquid crystal 105 and a white display is applied when no voltage is applied, is often used as the reflective liquid crystal display mode. This is because it is easier to obtain brightness than in the normally black mode.

However, when a normally white mode is employed in a liquid crystal display device, light leakage occurs at a boundary between adjacent pixels, which causes deterioration in contrast.

This is because the influence of the horizontal electric field parallel to the substrate surface becomes more remarkable than the electric field applied between the electrodes of each pixel and the opposing substrate, and the liquid crystal molecules existing in this portion are affected by the horizontal electric field. This is because domains of different liquid crystal alignment states are generated under the influence of the directional electric field. The boundary of the domain is observed as a disclination on or near the data line and the gate line. In the display, not only strong light leakage is observed in this portion, but also light leakage is observed in the vicinity thereof.

Normally, in a liquid crystal display device, in order to suppress the generation of a residual DC electric field due to the influence of impurity ions and the like in the liquid crystal and the alignment film material, and to prevent a flicker phenomenon in a display, the liquid crystal display device is used for every frame period and in the same frame. AC drive is used between adjacent pixels in the pixel.
For this reason, electric fields having different polarities exist at the boundary between adjacent pixels, and the electric field is twice as large as the electric field applied between the counter substrate and the (reflection) pixel electrode. It has become.

As a countermeasure for this, there is a method of physically hiding this light leakage. The BM 102 that blocks or absorbs light is formed on the opposite substrate, and a means for hiding the light leakage portion is used.

Although this method is simple, the BM10
2 is required, and the BM region must be secured in consideration of the bonding margin between the counter substrate and the element substrate. For this reason, the effective reflection area of the reflection pixel electrode 106 is considerably reduced.

In the case of a transmissive liquid crystal display device, the BM is formed on the element substrate, and the bonding accuracy can be improved to the mask positioning accuracy. However, in a reflection type liquid crystal display device which is observed from the counter substrate side, in reality, the BM has to be formed on the counter substrate.

The light leakage width due to disclination is 2
If the line width of the data lines or gate lines is 4 μm even when the width is 4 μm, the bonding accuracy between the counter substrate and the element substrate needs to be estimated about ± 2 μm including other margins, and the BM width needs about 6 μm. Becomes

For this reason, the 2 μm pixel region is shielded from light, and as a result, the effective reflection area of the reflection pixel electrode 106 cannot be utilized.

As another countermeasure, the cell gap (approximately the distance between the counter electrode and the pixel electrode) of the liquid crystal display device is reduced to about half that of the related art, and the vertical electric field between the pixel electrode 106 and the counter substrate is reduced around the pixel. Can be considered as a means of strengthening.

The cell gap is a factor of an optical parameter in a liquid crystal display device for effectively utilizing light, and is therefore limited to a liquid crystal operation mode suitable for this.

The liquid crystal material itself, which is another optical parameter, needs to have a refractive index anisotropy constant of about twice as large as that of the conventional liquid crystal material.
This response is quite limited.

In the future, as the definition becomes higher and the line width of the data lines and gate lines becomes narrower, the ratio of the bonding margin between the opposing substrate and the element substrate becomes larger, and the occupied area of the BM 102 increases. For this reason, a problem that the effective area of the reflective pixel electrode 106 is reduced is expected.

FIG. 1B shows an example in which the reflection pixel electrode itself has a scattering effect instead of the combination of the specular reflection pixel electrode and the scattering plate shown in FIG. 1A.

In this configuration, since the scattering effect is realized in the immediate vicinity of the display section, blurring at the outline of the image is less likely to occur than in the case of scattering through the thickness of the transparent substrate. In addition, it is possible to control the directivity of the reflected scattered light without absorbing light by a scattering plate or the like, which is advantageous for display luminance and contrast.

However, in the above structure, it is necessary to form any irregularities 111 on the reflective pixel electrode on the element substrate or its underlying film, and a processing step for this is added. This is also a factor that increases manufacturing costs.

Further, since the reflective pixel electrode has the irregularities 111, it is difficult to make the alignment of the liquid crystal uniform, and depending on the shape of the electrode and the structure of the upper film, there is a possibility that the accumulation of electric charges causing image sticking may occur. is there.

In a reflection type liquid crystal display device, it is essential to improve brightness in order to improve display quality such as visibility, contrast, and beauty. Therefore, the use of a material having a high reflectance is desired.

At present, materials made of aluminum and aluminum alloy are generally used. This has a reflectivity of 83 to 88% for visible light in actual use, and is selected in consideration of etching processing and material stability. In order to obtain a higher reflectance of 10% or more than the current material mainly composed of aluminum, it is conceivable to employ silver, a silver alloy, a dielectric multilayer film, or the like.

However, these materials are known to have corrosion due to oxidation and poor workability. Silver is easily oxidized and corroded. Further, there are problems such as peeling of the film at the time of processing and influence of the residue on the liquid crystal.

For this reason, some measures have been taken such as adding impurities to prevent this to silver and coating the surface, and some of them have been put to practical use, but there are many problems in reliability and productivity.

The dielectric multilayer film can obtain a reflectance close to 100% by laminating films having different refractive indexes. However, the workability of the inorganic dielectric film used for this is extremely poor.

When this film is laminated on the pixel electrode,
An arbitrary electric field cannot be applied to the liquid crystal due to the influence of the dielectric constant.

In the case of a specular reflection pixel electrode and a reflection pixel electrode on which a texture such as unevenness is formed, it is necessary to process the pixel unit. For this reason, it was difficult to use the above materials.

[0040]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems by considering the simplification of the process without the need for the counter BM and the reduction of the reflection area due to the positioning accuracy with the counter substrate. It is not necessary to expand the selection range of the reflective electrode material, and has a structure that does not affect the orientation of the liquid crystal easily.
Another object of the present invention is to realize a reflective liquid crystal display device which is easy to produce. As a result, it is possible to provide a means for improving the display quality such as the reflection luminance and the contrast and providing a highly reliable product at a low price.

[0041]

According to the present invention, a liquid crystal is interposed between a pair of substrates, and a pixel electrode comprising a transparent conductive film arranged in a matrix on one of the pair of substrates; In a liquid crystal display device in which a semiconductor element connected to a pixel electrode is formed, the one substrate is a transparent and insulating substrate, and the other substrate is a common substrate including a reflective layer and a transparent conductive film. It is characterized by having an electrode.

The above structure is characterized in that in a reflective or transflective liquid crystal display device, the reflective layer is separated from the pixel electrode and the common electrode, and the reflective layer is provided on the counter substrate side. Here, the reflection layer is a layer having a characteristic that the reflectance of a medium having a single material or a laminated structure to be used in the air is 30% or more.

The processing of the reflection layer on the counter substrate side is very simple because there is no need to perform processing according to design rules such as pixel electrodes. It is unlikely to be affected by the underlying film during processing. For this reason, the material selection range can be expanded. Since the pixel electrode uses ITO for which conditions have been established so far, it may be processed according to the conventional process rules.

Thus, as the electrode material, aluminum or a material containing aluminum as a main component has conventionally been generally used. However, optically, silver or silver oxide capable of obtaining higher reflectance or scattering characteristics and directivity can be obtained. Material, a dielectric multilayer film, a dichroic mirror,
Application of a hologram or the like becomes easy. By using a material having a high reflectance, the reflection luminance is increased, and a brighter display can be obtained.

It is also possible to realize a direct-view or projection-type liquid crystal display device for color display without using a color filter by reflecting only a specific visible light wavelength region with a dichroic mirror or the like.

Further, by separating the reflective layer and the electrode, it is possible to coat the reflective film material. This facilitates not only means for preventing the reflection film material such as silver from being oxidized, but also the effect of processing residues that affect the liquid crystal retention and the like.

Even when a reflective film having a texture shape having scattering and directivity is formed, it is only necessary to process the counter substrate directly on the reflective film material or to process the underlying film, and the yield of the element substrate is increased. Does not deteriorate.

Further, since it is not necessary to form a texture on the pixel electrode or the common electrode itself, the most important cell gap in the liquid crystal can be made uniform, and not only a structure in which color unevenness is hardly caused, but also the alignment is in the display region. It is easy to make the whole uniform, and it is possible to prevent poor alignment which causes disclination due to structural factors such as unevenness and steps.

The present invention can be easily applied to a structure with a narrow pixel pitch due to high definition of pixels without considering a processing space such as a contact hole.

As a semiconductor element described in the specification, a thin film transistor (TFT) is typical.
In addition, an element including a metal-insulator-metal (MIM), a thin-film diode, a varistor, an insulated gate field-effect transistor, a bipolar transistor, or the like may be used.

According to another aspect of the present invention, a liquid crystal is sandwiched between a pair of substrates, and a pixel electrode disposed in a matrix on one of the pair of substrates, and a semiconductor element connected to the pixel electrode are provided. Is formed, the one substrate is a transparent and insulating substrate, the other substrate has a common electrode comprising a reflective layer and a transparent conductive film on the other substrate, the reflective layer and The common electrode is electrically connected.

By connecting the reflective layer and the common electrode and electrically setting them at the same potential, residual DC due to electrostatic floating charges and impurity ions in a substance between the reflective layer and the common electrode can be obtained.
Prevent the occurrence of minutes.

According to another aspect of the present invention, a liquid crystal is sandwiched between a pair of substrates, and a pixel electrode arranged in a matrix on one of the pair of substrates and a semiconductor element connected to the pixel electrode are provided. Is formed, the one substrate is a substrate having transparency and insulating properties, a λ / 4 plate is provided on the back surface of the substrate surface on which the switching element is formed, and the other substrate is provided with a λ / 4 plate. Has a common electrode comprising a reflective layer and a transparent conductive film.

The above structure is characterized in that, in a reflective or transflective liquid crystal display device, the display observation surface is the back surface of the element substrate, and the λ / 4 plate is arranged on the observation surface of this substrate.

FIGS. 2A and 2B show the polarization state of output light when linearly polarized light is incident on a λ / 4 plate.

First, the case of transmission will be described with reference to the optical system of FIG. Here, it is assumed that the incident light 201 is transmitted through the first polarizing plate 202, the first λ / 4 plate 203, the second λ / 4 plate 204, and the second polarizing plate 205 in this order. In this optical system, the angle between the transmission axis of the first polarizing plate 202 and the slow axis of the first λ / 4 plate 203 is 4
5 °, the first λ / 4 plate 203 and the second λ / 4 plate 2
04 has the same slow axis direction, and the first polarizing plate 202 and the second polarizing plate 205 have the same transmission axis direction.

The incident light 201 passes through the first polarizing plate 202, and is output as linearly polarized light 206 parallel to the transmission axis of the polarizing plate 202. The λ / 4 plate 203 is an optical medium having a uniaxial property whose refractive index is different in the X axis and the Y axis. When the linearly polarized light 206 enters this optical medium,
The light is separated into an ordinary light component and an extraordinary light component, and becomes light having a phase difference therebetween. When the phase difference is λ / 4 at the distance (film thickness) where light travels in the optical medium, λ /
There are four plates. As a result, the output light from this medium becomes elliptically polarized light. At this time, when the linearly polarized light 206 is incident at an angle of 45 ° with the axis of the first λ / 4 plate 203 as shown in the present optical system, it becomes circularly polarized light 207.

Further, this circularly polarized light 207 is converted to the second λ / 4
After passing through the plate 204, the phase difference between the ordinary light component and the extraordinary light component is further added by λ / 4 in this optical medium. As a result, the circularly polarized light 207 becomes the linearly polarized light 208, and the linearly polarized light 208 at this time is the linearly polarized light 20 immediately after passing through the polarizing plate 202.
6 is different from the 90 ° direction. That is, light that has passed through the first λ / 4 plate 203 and the second λ / 4 plate 204 is equivalent to light that has passed through the λ / 2 plate. Linear polarized light 2
Since the polarization axis of 08 is perpendicular to the transmission axis of the second polarizing plate 205, the linearly polarized light 208 is absorbed by the second polarizing plate. This indicates that the image is recognized as black by the observer.

Next, the case of reflection will be described with reference to the optical system shown in FIG. Here, the incident light 209 is
10, a case where light is transmitted in the order of the λ / 4 plate 211, reflected by the reflection medium 212, and then transmitted in the order of the λ / 4 plate 211 and the polarizing plate 210 is considered. In this optical system,
It is assumed that the angle between the transmission axis of the polarizing plate 210 and the slow axis of the λ / 4 plate 211 is 45 °.

The incident light 209 passes through the polarizing plate 210,
Linear polarized light 213 parallel to the transmission axis of the polarizing plate is output, and further passes through the λ / 4 plate 211, and circularly polarized light 214 is output, as in the case of transmission.

The circularly polarized light 214 is reflected by the reflection medium 212 and becomes reflected light 215. The polarization state 216 of the reflected light 215 is the same as that of the circularly polarized light 214. This light 21
6, linearly polarized light 217 by the λ / 4 plate 211
The polarization axis of the linearly polarized light 217 is
Since it is perpendicular to the transmission axis of 0, the linearly polarized light 217 is absorbed by the polarizing plate. This indicates that the image is recognized as black by the observer.

Here, the fact is used that light does not change its properties even if it transmits through an optically isotropic medium or is reflected at a predetermined angle. Here, the predetermined angle is an angle formed by a normal direction of the reflection surface of the reflection layer made of aluminum and is about 12 ° or less.

When the light is reflected at an angle larger than this, the incident light is separated into two components of the S-wave component and the P-wave component at a predetermined ratio, which causes a reduction in contrast.

FIGS. 3A and 3B show the definitions of the P wave and the S wave. Here, as shown in FIG. 3A, the polarized light whose displacement vector of the incident light is in the incident plane is a P-wave, and the polarized light perpendicular to the incident plane is an S-wave as shown in FIG. 3B.

The limitation on the reflection surface and the incident light becomes severe especially in a projection type liquid crystal display device using a strong incident light source.
Usually, the angle of incidence of light (the angle formed with the normal to the reflection surface) is usually several degrees or less, preferably 2 degrees or less, so that the above problem does not occur.

However, in a reflection type liquid crystal display device, a wide range of light is used as incident light. Therefore, it cannot be used within the above-mentioned restrictions. For this reason, an experimental substrate was prepared in which a λ / 4 plate was experimentally arranged on a reflection plate, and a polarizing plate having its axis and the polarization axis set at 45 ° was provided. As a result of observation by changing the angle of the incident light, it was confirmed that a black level without any problem was obtained in a normal use environment.

That is, the limitation of the reflection surface and the incident light does not cause a remarkable problem when used in a reflection type liquid crystal display device used for external light or incident light at a fluorescent lamp level.

From the above, when the λ / 4 plate and the polarizing plate are arranged on the back surface of the element substrate, the semiconductor layer, the data line, the gate line,
Light reflected by the material used for the capacitor electrode and the like is absorbed by the polarizing plate, and is recognized as black by an observer from the back surface of the element substrate.

The present invention makes use of the above-mentioned features, and
It is used as M.

It is possible to control the disclination which appears due to the difference in the alignment state of the liquid crystal so that it exists only on the bus line by the pretilt angle, the pixel shape, the structure, and the cell gap. Light leakage due to disclination can be hidden by a gate line or the like. Here, by using a λ / 4 plate and a polarizing plate, the reflected light of these shields themselves can be absorbed, and the function as a BM can be achieved.

Although the polarizing plate is used here, any organic material may be used as long as it has a function of outputting linearly polarized light of a predetermined axial component to random incident light and absorbing or reflecting other components. , Inorganic materials, or both.

Further, since it is not necessary to form the BM on the opposing substrate, it is not necessary to consider the bonding margin as in the related art. The present invention can be applied to a liquid crystal display device in which the effective area of the reflective electrode is high definition. This is particularly effective in a high-definition liquid crystal display device having a pixel pitch of several tens μm or less.

According to another aspect of the present invention, a liquid crystal is sandwiched between a pair of substrates, and a pixel electrode arranged in a matrix on one of the pair of substrates and a semiconductor element connected to the pixel electrode are provided. Is formed, the one substrate is a substrate having transparency and insulation, the other substrate has a common electrode consisting of a reflective layer and a color filter layer and a transparent conductive film, A color filter layer is disposed between the reflection layer and the common electrode.

In the above configuration, a color filter layer is provided on the reflective layer, and a common electrode is provided thereon, thereby realizing a color display.

Here, the material of the color filter may be a material in which a pigment is filled in an organic resin containing acrylic or polyimide as a main component, or a material in which only a visible light wavelength component in a specific band is transmitted using an inorganic material.

The color filter layer is made of an organic resin film containing acrylic or polyimide as a main component or an inorganic material made of silicon oxide, silicon nitride, or the like, and is flattened or protected at the same time. Alternatively, an overcoat layer for the purpose of forming a separation membrane may be formed.

[0077]

[Embodiment 1] An embodiment of the present invention will be described. This embodiment is an example of a direct-view type reflective or transflective type liquid crystal display device, in which the number of masks used during an element substrate manufacturing process is reduced as compared with the conventional structure to reduce the processing time and cost. State.
Note that the details of the element substrate, which is one of the components of the liquid crystal display device, may follow the method described in Japanese Patent Application No. 11-191093. First, the structure of the element substrate will be briefly described with reference to FIGS. 4A and 4B and FIG.

On the substrate 401, a silicon nitride oxide film 4
02 was formed as a base film for the purpose of preventing impurity diffusion from the substrate 401. A thin film transistor (TFT) 403 is formed at a desired position thereon. TFT40
Reference numeral 3 denotes an active layer 404 made of crystalline silicon, a gate wiring 409 made of a conductive material, and a gate insulating film 408 for insulating the gate wiring 409 and the active layer 404, which are present in a pixel region and a driving circuit region around the pixel region. .

The active layer 404 of the TFT 403 has
By using the ion doping method, an n-type or P-type impurity element is added to a desired active layer region at a desired concentration. As a result, the LDD region 405, the source region 406, the drain regions 407,
A channel type TFT (not shown) is formed.

The data line 412 and the pixel electrode 413 are connected to the source region 406 and a part 407 of the drain region through contact holes, respectively.
Further, the other region 415 of the drain region and the capacitance wiring 41
4, the gate insulating film 408 is used as a dielectric film,
A storage capacitor is formed.

On the TFT 403, a protective insulating film 410 made of an inorganic material and an interlayer insulating film 411 made of an organic film are formed.

On the interlayer insulating film 411, titanium (T
i) or data wiring 4 made of aluminum (Al) alloy
12 and a pixel electrode 413 made of indium oxide / tin oxide (ITO). Note that the data wiring 412 and the pixel electrode 413 are arranged at positions where they are not electrically connected to each other.

In this configuration, the structures of the TFTs and wirings are optimized so that the element substrate can be manufactured with a relatively small number of masks. In fact, an element substrate having this configuration can be manufactured with seven masks, and a film forming step, a patterning step, an etching step, a resist peeling step,
A cleaning step, a drying step, and the like that occur accompanying this are reduced. As a result, effects such as an improvement in yield, a reduction in process time, and a reduction in cost can be expected.

Next, a process for manufacturing the counter substrate 502 will be described with reference to FIG. This substrate forms a liquid crystal display device in combination with the element substrate 501 described above.

In FIG. 5, an alkali-free glass such as the substrate 401 described in the section of the element substrate manufacturing process was used for the substrate 503.

[0086] A reflective layer 504 is formed on the substrate 503 by a vacuum evaporation method. The reflective layer 504 was formed by laminating silver as a main reflective material at 1000 ° and SiO ₂ for protecting silver at 2500 °.

At the time of silver deposition, a shadow mask was used to form a film in a region corresponding to the display portion so that a positioning marker and the like were not hidden. After silver deposition, SiO ₂ was deposited over the entire substrate to form a reflective layer 504.

After the formation of the reflection layer, a color filter 505 is applied by spin coating. Thereafter, preliminary curing is performed at 80 ° C. for 5 minutes on a hot plate. Then, exposure is performed using a photomask according to a photolithography method. The substrate on which this processing has been completed is immersed in a developing solution and shaken to perform development. As the developing solution, a 0.2% aqueous solution of tetramethylammonium hydroxide is used. After immersion in the developer for about 1 minute, wash in running water.

Since the color filter 505 contains a pigment, it may not be possible to remove the pigment with running water alone. Therefore, washing is performed by injecting water onto high-pressure compressed air.

When it is confirmed that the pattern of the color filter 505 is cleanly formed, the main firing is performed at 250 ° C. for one hour in a clean oven. The above steps are performed for three types of color filters, red, blue, and green. Also, the order of forming the color filters 505 can be any color, starting from any color and ending with any color.

After the three color filters are formed,
An overcoat material 506 is applied thereon. In this example, an acrylic overcoat material was used. Apply to the substrate by spin coating, 8 on hot plate
Preliminary curing is performed at 0 ° C. for 3 minutes. Thereafter, main firing is performed in a clean oven at 220 ° C. for one hour.

Next, a common electrode 507 made of a transparent conductive film is formed on the substrate. On the common electrode 507, an ITO film was formed to a thickness of 1000 ° by a sputtering method. After film formation, baking was performed at 250 ° C. for 1 hour in a clean oven to improve transmittance.

In this embodiment, a layer composed of the color filter 505 and the overcoat 506 is a color filter layer.

Next, the element substrate 501 and the opposing substrate 502
The process of manufacturing an active matrix liquid crystal panel will be described with reference to FIG.

First, the element substrate 501 and the counter substrate 50
An alignment film 508 is formed for No. 2. Usually, a polyimide resin or a polyamic acid-based resin is used for the alignment film of the liquid crystal display element. In this embodiment, the alignment film SE7 manufactured by Nissan Chemical Industries, Ltd. is used.
792 was used. An offset printing method was used for forming the alignment film. After the alignment film 508 is formed,
Pre-curing for 90 seconds in the oven
The main baking was performed at 00 ° C. for 90 minutes. The thickness of the alignment film 508 is about 500 ° after the main firing.

A rubbing process is performed on both of the substrates 501 and 502 that have been subjected to such a process so that the liquid crystal molecules are aligned with a certain pretilt angle. The rubbing angle was set so as to form a twist of 55 degrees when a liquid crystal material 510 described later was introduced into the panel. Note that the twist angle is not limited to 55 degrees, but may be 5 degrees.
The angle may be set to about 0 to 60 degrees to improve the contrast.

After removing the dust generated by the rubbing and the loose hair of the rubbing cloth by washing, the counter substrate 50 is removed.
0 is coated with a sealing material (not shown). Temporary curing of the sealing material is performed in a clean oven at 90 ° C. for 30 minutes.

After the temporary curing, a spherical spacer 509 is further dispersed. The spacer 509 used in this embodiment is 4 μm
Is a plastic sphere with a diameter of

Then, the element substrate 501 on which the pixel portion and the driving circuit are formed and the counter substrate 502 are accurately bonded. A columnar filler (not shown) having a diameter of 4.2 μm is mixed in the sealing material. Can be attached.

In order to achieve accurate gap control, a pressure of 0.3 to 0.8 kgf / cm 2 is applied uniformly in a direction perpendicular to the surface of the bonded substrates and over the entire surface of the substrates. 12 at 160 ° C in a clean oven
Baking for 0 minutes was performed.

Then, after waiting for the substrate to cool, the bonded substrate was cut into a desired panel size and formed into a panel shape.

Thereafter, a liquid crystal material 510 was injected into the inside of the panel. The liquid crystal was prepared by mixing a chiral material S-811 into a material having a refractive index anisotropy Δn of 0.124 and adjusting the helical pitch length to 60 to 80 μm. After confirming that the entire inside of the panel is filled with the liquid crystal 510, the panel is completely sealed with a sealing agent (not shown). Table 1 shows the structural specifications of the liquid crystal display device manufactured here.

[0103]

[Table 1]

FIG. 7 is a top view of the element substrate 700, showing a positional relationship between the pixel portion 701, the driving circuit portions 702, 703, and 704 and the sealing material 711. A scanning signal driving circuit 702 as a driving circuit around the pixel portion 701
And an image signal driving circuit 703.

Further, a signal processing circuit 704 such as a CPU or a memory may be additionally provided. The driving circuits provided around the pixel section are configured based on a CMOS circuit. These drive circuits are connected to an external input / output terminal group 706 by a connection wiring group 705. In the pixel portion 701, the gate wiring group 707 extending from the scanning signal driving circuit 702 and the image signal driving circuit 70
3 form a pixel by intersecting in a matrix form a data line group 708 extending from
09 and a storage capacitor 710 are provided.

The sealant 711 is formed outside the pixel portion 701, the scanning signal control circuit 702, the image signal control circuit 703, and other signal processing circuits 704 on the substrate 700 and inside the external input / output terminal 706. I do.

On the outside of the panel, a flexible printed circuit (FPC) is used.
Reference numeral 712 is connected to the external input terminal 706 and used to input an image signal or the like. The connection wiring 705 is connected to each drive circuit.

The external input / output terminal 706 is connected to the data line 708
Alternatively, it is formed of a conductive metal film in the same configuration as the drain wiring 713. The FPC 712 has a structure in which copper wiring is formed on an organic resin film such as polyimide, and is connected to the external input / output terminal 706 with an anisotropic conductive adhesive.

The anisotropic conductive adhesive is composed of an adhesive and particles having a conductive surface with a diameter of several tens to several hundreds μm mixed with the adhesive and plated with gold or the like. By contacting the terminal 706 and the copper wiring, an electrical contact is formed at this portion.

The FPC 712 protrudes outside the external input / output terminal 706 and is bonded to the substrate 700 in order to increase the bonding strength with the substrate 700, and a resin layer is provided at the end to increase the mechanical strength in this portion. .

Next, a method of arranging optical films having a polarizing function and a viewing angle improving function formed on the display observation surface of the panel, that is, the back surface of the element forming surface of the element substrate in this case, will be described with reference to FIG. .

First, a forward scattering plate 51 is provided on the display surface side of the panel.
Attach 1. This forward scattering plate 511 has a haze value of 50.
Good optical characteristics were obtained by using those having a content of ~ 75%.

As the polarizing plate 512, a high-transmission high-polarization type is used in order to increase the reflectance at the white level. The one used in this example has a single transmittance of 44% and a polarization degree of 99.9.
5%.

Further, depending on the display condition of the liquid crystal display device, a process having a function of suppressing reflection of external light on the polarizing plate 512, for example, an anti-reflector process or an anti-glare process may be performed on the polarizing plate 512.

Through the above process, a reflection type liquid crystal display device can be manufactured.

In this embodiment, as shown in FIG.
The surface of the reflection layer of the counter substrate is made flat to form a so-called specular reflection layer 801, on which a color filter 802, an overcoat 803, and a common electrode 804 are formed.
However, the structure having the texture shape 805 having scattering and directivity on the surface of the reflective layer is not limited to this method, as shown in FIG. 8B. Is also good. In this case, among the optical films disposed on the display surface side of the panel, the forward scattering plate is not required.

Alternatively, as shown in FIG. 8C, a conductive metal film 8 made of silver, a silver alloy, aluminum, an aluminum alloy, a dielectric multilayer film, or a combination thereof.
06, a hologram 8 based on the structure of a diffraction grating
07 may be formed so that the hologram structure selectively reflects light of a specific wavelength.

Alternatively, instead of the reflective layer 801 formed on the substrate 800, a layer having both reflective and transmissive properties, for example, a dielectric multilayer film 808 having a half mirror or semi-transmissive property is formed. The present invention can also be applied to a so-called semi-transmissive liquid crystal display device that can be used in any of the transmission modes.

An embodiment having a liquid crystal specification capable of ensuring a higher contrast will be described below.

Example 2 The production of the element substrate and the counter substrate is in accordance with Example 1.

Referring to FIG. 10, a process for manufacturing an active matrix liquid crystal panel from the element substrate 1001 and the counter substrate 1002 will be described.

First, the element substrate 1001 and the opposing substrate 1
002 is formed. Usually, a polyimide resin or a polyamic acid-based resin is used for the alignment film of the liquid crystal display element. In this embodiment, an alignment film SE7792 manufactured by Nissan Chemical Industries is used. An offset printing method was used for forming the alignment film. After forming the alignment film 1003, temporary curing was immediately performed at 80 ° C. for 90 seconds, and further, main firing was performed at 200 ° C. for 90 minutes in a clean oven. Alignment film 10
The film thickness of 03 is about 500 ° after the main firing.

Both substrates 1001 that have been subjected to such processing
And 1002 are subjected to a rubbing treatment so that the liquid crystal molecules are aligned with a certain pretilt angle. The rubbing angle was set so as to form a 90-degree twist when a liquid crystal material 1005 described later was introduced into the panel. The twist angle is not limited to 90 degrees, but may be set to about 75 to 90 degrees to improve the reflectance at the white level.

After removing the dust generated by the rubbing and the loose hair of the rubbing cloth by washing, the counter substrate 10 is removed.
02 is coated with a sealing material (not shown). Temporary curing of the sealing material is performed in a clean oven at 90 ° C. for 30 minutes.

After the temporary curing, the spherical spacer 1004
Spray. The spacer 1004 used in this embodiment is
Plastic sphere with a diameter of 2.5 μm.

Then, the element substrate 1001 on which the pixel portion and the driver circuit are formed and the counter substrate 1002 are accurately bonded. A columnar filler (not shown) having a diameter of 2.7 μm is mixed in the sealing material, and the two substrates 1001 and 1002 are accurately positioned with a uniform interval by the filler and the spacer 1004. Can be attached.

In order to achieve accurate gap control, a pressure of 0.3 to 0.8 kgf / cm 2 is applied uniformly in a direction perpendicular to the surface of the bonded substrates and over the entire surface of the substrates. 12 at 160 ° C in a clean oven
Baking for 0 minutes was performed.

Then, after waiting for the substrate to cool, the bonded substrate was cut into a desired panel size to form a panel.

Thereafter, a liquid crystal material 1005 is provided inside the panel.
Was injected. The liquid crystal material is ZLI4792 manufactured by Merck.
And a mixture prepared by mixing the company's chiral material S-811 and adjusting the helical pitch length to 60 to 80 µm. After confirming that the entire inside of the panel is filled with the liquid crystal 1005, the panel is completely sealed with a sealing agent (not shown).

Table 2 shows the structural specifications of the liquid crystal display device manufactured here.

[0131]

[Table 2]

Next, a method of arranging optical films having a polarizing function and a viewing angle improving function formed on the display observation surface of the panel, that is, the back surface of the element forming surface of the element substrate in this case, will be described with reference to FIG. .

First, as shown in FIG. 10, a forward scattering plate 1006 is attached to the display surface side of the panel. If the haze value of this forward scattering plate 1006 is 50-75%, good optical characteristics can be obtained.

The polarizing plate 1008 and the λ / 4 plate 100
7 is attached. Here, the polarizing plate 1008 and the λ / 4 plate 10
07, the λ / 4 plate 1007
And the polarizing axis of the polarizing plate 1008 are arranged so as to form an angle of 45 degrees with each other. Here, the λ / 4 plate 1007 used a broadband film usable at a visible light wavelength.

The broadband λ / 4 plate 1007 may be manufactured by combining a standard λ / 4 plate and a standard λ / 2 plate made of a polycarbonate-based material, or a commercially available wideband λ / 4 plate may be used. However, in order to realize good black, 380-8
In the wavelength region of 00 nm, 4/2
It is preferable to have a broadband property so as to have a birefringence phase difference of 0 to 6/20.

As the polarizing plate 1008, a high-transmission high-polarization type is used in order to increase the reflectance at the white level. The one used in this example had a single transmittance of 44% and a degree of polarization of 99.
95%.

In FIG. 10, the directions of the optical axes of the polarizing plate 1008 and the λ / 4 plate 1007 are also important, and have a close relationship with the twist angle of the liquid crystal 1005.
For example, when the twist angle is set to 90 degrees, the polarization axis of the polarizing plate 1008 forms an angle of 90 degrees with the rubbing direction applied to the element substrate 1002.
It should just be stuck.

Further, depending on the display condition of the liquid crystal display device, a process having a function of suppressing reflection of external light on the polarizing plate 1008, for example, an anti-reflector process or an anti-glare process may be performed on the polarizing plate 1008.

Through the above process, a reflection type liquid crystal display device can be manufactured.

The construction of the optical film as described above has the following merits. As shown in FIGS. 11A to 11C, external light incident on the liquid crystal display device is converted into circularly polarized light by the polarizing plate 1101 and the λ / 4 plate 1102 and introduced into the panel. Of the circularly polarized light, light reflected on the back surface (display surface side) of the substrate of the element substrate 1103 or a reflective film in the element substrate 1103, that is, light returned without passing through the liquid crystal layer is , Λ / 4 plate 1102 reconverts the light into polarized light perpendicular to the polarization axis of the polarizing plate 1101. Therefore, such light is absorbed by the polarizing plate 1101 and does not enter the eyes of the observer.

On the other hand, as shown in FIGS. 12A to 12C, the light whose polarization state has changed after passing through the liquid crystal layer 1203 passes through the polarizing plate 1201 according to the change state. It will be in the observer's eyes. That is, unnecessary light is absorbed by the polarizing plates 1101 and 1201,
Since only necessary light is transmitted, the contrast is improved.

The film having reflectivity in the element substrate 1103 becomes BM from a different viewpoint. This is because, as described above, light reflected by a reflective film or the like in the element substrate 1103 does not eventually enter the eyes of the observer.

Since the light-shielding film also functions as a BM, it hides light leakage, that is, so-called disclination, which is caused by disturbance of the alignment of the liquid crystal at the periphery of each pixel when the liquid crystal display device is driven. Should be arranged as follows. In order to secure the aperture ratio as much as possible, it is desirable that the area occupied by the light-shielding film is as small as possible.

In the first embodiment (FIGS. 4 and 5) or the present embodiment (FIG. 10), in the pixel regions of the element substrates 501 and 1001, the main film exhibiting the light shielding property is the active layer 404 for forming the thin film transistor. , Gate line (gate electrode) 4
09, a data line 412, and a capacitor wiring 414.

First, the capacitance wiring 414 will be described. The storage capacitor in this embodiment is configured such that the capacitor wiring 414 and the drain region 415 of the TFT are both electrodes of the capacitor, and a part of the gate insulating film 408 is a dielectric film between the electrodes.

The dielectric film of the storage capacitor is the gate insulating film 40.
The same material as that of No. 8 is used, such as SiO2 or SiON. When a storage capacitor is formed using SiO2, SiON, or the like as a dielectric film, the relative dielectric constant of the dielectric film is about 3.8. Therefore, when the dielectric film thickness is 750 °, the electric capacitance per unit area is 0.75 fF / It is about μm ² .
On the other hand, in each pixel, the electric capacitance required for those pixels is (0.06 to 0.07 [fF / μm ² ]) × (pixel area [μm ² ]) [fF] or more.

That is, when SiO 2 or SiON is used as the dielectric as in the present embodiment, the capacitance wiring 414 needs to occupy about 10% of the entire area of the opening formed by the pixel electrode 413. Can also cause a decrease in the aperture ratio.

An improvement measure for achieving a higher aperture ratio will be described in a third embodiment.

[Embodiment 3] In this embodiment, in another example of a direct-view type reflective or transflective liquid crystal display device,
A configuration that can achieve a higher aperture ratio than the configurations of the first and second embodiments will be described.

The details of the element substrate, which is one of the components of the liquid crystal display device, are described in Japanese Patent Application No. 11-053.
424 (Semiconductor Energy Laboratory).

First, the structure of the element substrate will be described with reference to FIG.
A brief description will be given using (a) and (b).

[0152] A silicon nitride oxide film 1302 was formed over the substrate 1301 to serve as a base film for preventing impurity diffusion from the substrate 1301. A thin film transistor (TFT) 1303 is formed at a desired position thereon.

The TFT 1303 exists in the pixel region and the driving circuit region around the pixel region, and includes an active layer 1304 made of crystalline silicon and a gate wiring 130 made of a conductive material.
9, a gate insulating film 1308 that insulates the gate wiring 1309 from the active layer 1304.

In the active layer 1304 of the TFT 1303, an n-type or P-type impurity element is added to a desired active layer region at a desired concentration by using an ion doping method. As a result, the LDD region 130
5, a source region 1306, a drain region 1307, and a P-channel TFT (not shown) are formed.
Among them, the source region 1306 and the drain region 1307
Are the data wiring 1312 and the drain wiring 131, respectively.
3 is connected through a contact hole.

On the TFT 1303, a protective insulating film 1310 made of an inorganic material and a first interlayer insulating film 1311 are formed.

Data wiring 1312, drain wiring 131
3 and a second interlayer insulating film 1314 is formed on the first interlayer insulating film 1311. On this, a capacitor wiring 1315 made of aluminum is formed in a region to be a pixel matrix circuit. This capacitance wiring 1315 is anodized, and an oxide film 1316 made of aluminum oxide is formed on the surface thereof. The thickness of the oxide film 1316 is about 50 nm.

On this, a pixel electrode 1317 is formed. The pixel electrode 1317 is made of indium oxide / tin oxide (I
TO), is connected to the drain wiring 1313 through the contact hole, and partially overlaps with the data wiring 1312, the gate wiring 1309, and the capacitor wiring 1315. In particular, the capacitor wiring 1315 forms a storage capacitor using the oxide film 1316 as a dielectric film.

The structure and steps of the counter substrate 1402 and the steps of manufacturing a liquid crystal display device from the element substrate 1401 and the counter substrate 1402 are the same as those described in Embodiment 1 or 2. Thus, a liquid crystal display device as shown in FIG. 14 can be manufactured.

Further, as shown in FIG. 15, the reflecting film may have a texture structure 1501 to realize scattering. In this case, the forward scattering plate becomes unnecessary.

FIG. 20 is a cross-sectional view illustrating the significance of the liquid crystal display device described in this embodiment.

External light 2002 introduced from the light source 2001 into the liquid crystal display device 2000 reaches the element substrate 2006 through the polarizing plate 2003, the λ / 4 plate 2004, and the forward scattering plate 2005.

A part (not shown) of the incident light 2002 is
The light is reflected on the surface of the element substrate 2006 (the interface between the forward scattering plate 2005 and the element substrate 2006), and a part 2002a is reflected on the surface of the reflective film on the element substrate.
Such light 2002a is not modulated in its polarization state at all, and is absorbed here by the action of the λ / 4 plate 2004 and the polarizing plate 2003 on the return path, so that the observer's eyes 2a
It does not enter 010. That is, all the reflective films on the element substrate are BM in other words.

Most of the other light 2002b passes through the liquid crystal layer 2007 and the color filter layer 2008 after passing through the element substrate.
And reflected by the reflective layer 2009. Then light 2
002b follows the reverse path to the incidence. Of such light 2002b, the light whose polarization state has been modulated by the liquid crystal in some way depends on the way of receiving the light.
The polarized light component parallel to the transmission axis of the polarized light remains, and the polarized light component enters the observer's eye 2010 only after passing through the polarizing plate. On the other hand, light that has not undergone any modulation in its polarization state even after passing through the liquid crystal follows exactly the same fate as the light 2002a and does not enter the observer's eye 2010.

As described above, of the light 2002 introduced into the liquid crystal display device 2000, unnecessary light 2002a not related to display is cut off, while light 200 related to display is cut off.
For 2b, a high contrast display can be obtained by selectively outputting to the outside of the liquid crystal display device by the modulation action of the liquid crystal.

As described above, the reason why the aperture ratio is reduced in the first and second embodiments is that the ratio of the area of the capacitor wiring to the area of the pixel electrode must be increased.

Therefore, in this embodiment, as shown in FIGS. 13 to 15, a capacitor electrode 1315 made of aluminum is formed on the second interlayer insulating film 1314, and this surface is anodized to convert the aluminum oxide from aluminum oxide. A pixel electrode 1317 is formed directly on the insulating film 1316. With such a structure, a storage capacitor is formed in which the capacitor wiring 1315 and the pixel electrode 1317 serve as both electrodes of the capacitor, and the insulating film 1316 formed therebetween is a dielectric film.

Since the relative dielectric constant of aluminum oxide is as large as 8 and its film thickness can be made 500 °,
A capacity as large as 4 to 5 times the conventional storage capacity can be formed.

In other words, when the required storage capacity is the same in the first and second embodiments and that of the structure employed in this embodiment, in the case of the structure employed in the embodiment of the present invention, Reduces the area of the capacitor wiring 1315 by a fraction.
This can be reduced to the following, which is effective for increasing the aperture ratio.

Furthermore, the structure of the gate line 1309 and the data line 1312 and the arrangement of the capacitor wiring 1315 may be properly used as follows according to the pixel size of the panel.

As shown in FIG. 16A, when the pixel size is about 50 μm × 150 μm or larger,
By arranging the gate line 1601 and the data line 1602 in the region corresponding to the edge of each pixel electrode 1603, and increasing the width of either the gate line 1601 or the data line 1602 to about 3 to 6 μm, The liquid crystal display device may also serve as a so-called black matrix that hides most of the light leakage (disclination) due to the disorder in the alignment of the liquid crystal that appears when the liquid crystal display device is driven.

The capacitor wiring 1604 is arranged so as to overlap either the gate line 1601 or the data line 1602, and is hidden by making the gate line 1601 or the data line 1602 thicker in each pixel region. If a disclination exists in a portion where no disclination exists, the portion may be preferentially arranged in that portion.

On the other hand, as shown in FIG. 16B, when the pixel size is smaller than about 50 μm × 150 μm,
The gate line 1605 and the data line 1606 are preferably arranged in regions corresponding to the edge of each pixel electrode 1607, and the width of both wirings is preferably reduced to 2 μm or less to increase the aperture ratio. The capacitor wiring 1608 is disposed so as to overlap with both the gate line 1605 and the data line 1606, so that a necessary storage capacitor is used here, and furthermore, the capacitor wiring 1608 is also disposed so as to cover the periphery of each pixel electrode 1607. (That is, the disclination is almost hidden only by the capacitance wiring 1608).

[Embodiment 4] In this embodiment, a reflection type liquid crystal display device of a projection type will be described with reference to FIG.

Most of the details of the element substrate, which is one of the components of the liquid crystal display device, are described in Example 1.
-According to the method described in Example 3.

However, the difference from the element substrate structures shown in Examples 1 to 3 is that, as shown in FIG.
That is, a light shield 1701 made of a metal film exists so as to overlap with the T element.

The light shield 1701 is provided to prevent light introduced from the light source of the projection device into the liquid crystal display device from being directly or indirectly applied to the TFT element 1702. Thereby, the TFT 1702
To prevent an increase in off-state current due to light of the light source, and take measures against crosstalk and color unevenness of a displayed image due to the increase.

Next, a counter substrate 1703 which is another component of the liquid crystal display device will be described. In the present embodiment, a reflection layer 1707 mainly made of an aluminum alloy and a dielectric multilayer film is used. A non-alkali glass substrate or a quartz substrate is used as the substrate. here,
An alkali-free glass substrate having the same material as the element substrate 1700 was used. Details will be described with reference to FIG.

As shown in FIG. 9A, an aluminum alloy 903 and a dielectric multilayer film 904 are formed as a reflection layer 902 on a substrate 901. As the aluminum alloy 903, a material containing 1% of titanium in aluminum was used. The dielectric multilayer film 904 was formed by laminating eight layers of materials having refractive indices of 1.4 and 2.1 by a vacuum evaporation method (up to four layers are shown in the figure) to increase the reflectance. Naturally, these films were formed by adjusting the film thickness so as to reflect a broadband light in the visible light region.

After forming the reflective layer, a common electrode 905 made of a transparent conductive film is formed on the substrate. An ITO film was formed on the common electrode 905 at a thickness of 1000 ° by a sputtering method. After film formation, 250 ° C in a clean oven to improve transmittance
Baking was performed for 1 hour.

Although the purpose here is to increase the reflectivity by using a dielectric multilayer film, it may be constituted by using a single-layer film 906 as shown in FIG. As described above, the reflection film may be a dichroic mirror 908, and the electro-optical device itself may be colored. With this structure, the size of the peripheral optical system can be reduced.

Next, the element substrate 1700 and the opposing substrate 17
A manufacturing process of a liquid crystal display device using No. 03 will be described with reference to FIGS.

Usually, a polyimide resin or a polyamic acid-based resin is used for the alignment film 1704 of the liquid crystal display element.
In this example, an alignment film SE7792 manufactured by Nissan Chemical was used.

For forming the alignment film, an offset printing method was used.
After forming the alignment film 1704, immediately 90 °
Pre-curing for 2 seconds, then 200 ° C in a clean oven
For 90 minutes. Alignment film 1704 after main baking
Is about 502 °.

Both substrates 1700 that have been subjected to such processing
And 1703 are subjected to a rubbing treatment so that liquid crystal molecules are aligned with a certain pretilt angle. The rubbing angle was set so as to form a 45 degree twist when a liquid crystal substance 1706 described later was introduced into the panel. The twist angle is not limited to 45 degrees and may be set so as to obtain desired optical characteristics.

After removing the dust generated by the rubbing and the hair loss of the rubbing cloth by washing, the counter substrate 17 is removed.
03 is coated with a sealing material (not shown). Temporary curing of the sealing material is performed in a clean oven at 90 ° C. for 30 minutes.

After the temporary curing, the spherical spacer 1705
Spray. The spacer 1705 used in this embodiment is
It is a plastic sphere having a diameter of 5.0 μm.

Element substrate 1 on which a pixel portion and a drive circuit are formed
700 and the opposite substrate 1703 are attached to each other. A columnar filler (not shown) having a diameter of 5.2 μm is mixed in the sealing material, and the two substrates 1700 and 1703 are precisely positioned at a uniform interval by the filler and the spacer 1705. Can be attached.

In order to achieve more accurate gap control, a pressure of 0.3 to 0.8 kgf / cm 2 is uniformly applied in a direction perpendicular to the surface of the bonded substrates and over the entire surface of the substrate. Simultaneously, baking was performed at 160 ° C. for 120 minutes in a clean oven. Then, after waiting for the substrate to cool, the bonded substrate was cut into a desired panel size to form a panel.

Thereafter, the liquid crystal material 1706 is provided inside the panel.
Was injected. The liquid crystal material is ZLI4792 manufactured by Merck.
And a mixture prepared by mixing the company's chiral material S-811 and adjusting the helical pitch length to 60 to 80 µm.

After confirming that the entire inside of the panel is filled with the liquid crystal 1706, the panel is completely sealed with a sealant (not shown).

Table 3 shows the structural specifications of the liquid crystal display device.

[0192]

[Table 3]

Hereinafter, the FP is connected to the external input / output terminal of the liquid crystal panel.
The fact that a necessary signal can be sent from the outside to the liquid crystal panel by attaching C is the same as that described in the first embodiment.

An example of an apparatus for projecting a reflection type liquid crystal panel will be described with reference to FIG. Light source 1801 of projection device
Is emitted into the optical system. First, the light is decomposed into an S-wave component 1810 and a P-wave component 1811 by a prism-type polarizing beam splitter (PBS) 1802.

The PBS 1802 has the property of reflecting only the S-wave component 1810 of light and transmitting the P-wave component 1811 on the reflecting surface inside the prism.
Therefore, only the S-wave component 1810 of the light travels to the dichroic prism 1803.

The dichroic prism 1803 decomposes the incident light 1810 into red, green, and blue components 1812 to 1814 without changing the polarization state thereof, and a panel 1804 for red and a panel 1 for green, respectively.
805, light is supplied to the panel 1806 for blue color.

Each of the three panels 1804 to 1806
The polarized light 1812 to 1814 incident on the panel is appropriately modulated in each panel according to the director arrangement of the liquid crystal. As a result, each light 1812 to 1814
Are emitted out of the panels as S-wave components and P-wave components in the respective panels 1804 to 1806, and returned to the dichroic prism 1803.

The red, green and blue lights 1815 to 1817 are recombined by the dichroic prism 1803,
The process proceeds to S1802. In PBS1802, this time the light P
Only the wave component 1818 passes through the reflecting surface of the prism, and this light is projected on the screen 1808 through the optical lens 1807. In this way, a color projection display is achieved.

Such an optical system can be incorporated in a main body of a front projector as shown in FIG. 19A and a rear projector as shown in FIG.
Thus, a projection type reflection type liquid crystal display device is completed.

[0200]

The liquid crystal display device described in this specification has the following three advantages. First, since the BM does not need to be formed on the opposing substrate, the bonding margin does not need to be considered, and a higher aperture ratio can be expected. In addition, the effective area of the reflective electrode can be applied to a high-definition liquid crystal display device. This shows that the present invention is advantageous not only for a direct-view reflective liquid crystal display device but also for a small reflective liquid crystal display device particularly used for a projection liquid crystal display device.

Second, since the reflective electrode is formed on the counter substrate side, processing is facilitated, and the range of selection of the material and configuration of the reflective layer is expected to be widened (silver electrode, dielectric multilayer film, hologram). You. As a result, a higher reflectivity can be obtained as compared with a conventional reflective electrode mainly containing aluminum. In addition, since the reflection layer and the counter electrode on the counter substrate are separated from each other, the material of the reflection layer can be overcoated or the like, and can be applied to a material whose reflectance is deteriorated by oxidation (such as a silver electrode).

Third, in the case where the reflective electrode itself has a scattering effect, since it is manufactured on the counter substrate side, this processing is not required for the element substrate, and the yield of the element substrate does not decrease in this step. For this reason, cost increase is suppressed. In the case where the reflective layer or several organic layers are formed on another upper layer, the common electrode on the counter substrate side and the pixel electrode on the element substrate side have a flat structure, and the cell gap can be made uniform. . For this reason, the orientation of the liquid crystal is uniform and easy.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a reflection type liquid crystal display device used in a conventional technique.

FIG. 2 is a diagram illustrating a state where incident light passes through a polarizing plate and a λ / 4 plate, and a diagram illustrating a polarization state at each point thereof.

FIG. 3 is a diagram illustrating a P wave and an S wave.

FIG. 4 is a sectional view showing the structure of an element substrate used in Example 1 or Example 2.

FIG. 5 is a cross-sectional view illustrating a structure of a liquid crystal display device used in Example 1.

FIG. 6 is a plan view showing the arrangement of wirings and electrodes on an element substrate used in Example 1 or Example 2.

FIG. 7 is a plan view showing an arrangement of a driving circuit and connection wiring of a liquid crystal display device in Examples 1 to 4.

FIG. 8 is a cross-sectional view showing an example of a structure which can be used as a counter substrate which is one of the components of the liquid crystal display device in Examples 1 to 3.

FIG. 9 is a cross-sectional view showing an example of a structure which can be used as a counter substrate which is one of the components of the liquid crystal display device in Embodiment 4.

FIG. 10 is a cross-sectional view illustrating a structure of a liquid crystal display device used in Example 2.

FIG. 11 is a schematic diagram showing the influence of incident light when the light is introduced into a liquid crystal display device in Examples 2 and 3.

FIG. 12 is a schematic diagram showing the effect of incident light when the light is introduced into a liquid crystal display device in Examples 2 and 3.

FIG. 13 is a cross-sectional view illustrating a structure of an element substrate used in Example 3 or Example 4.

FIG. 14 is a cross-sectional view illustrating a structure of a liquid crystal display device used in Embodiment 3.

FIG. 15 is a sectional view showing a structure of a liquid crystal display device used in Example 3.

FIG. 16 is a plan view showing an arrangement of wirings and electrodes of an element substrate used in Example 3.

FIG. 17 is a cross-sectional view illustrating a structure of a liquid crystal display device used in Example 4.

FIG. 18 is a schematic diagram illustrating a structure of an optical system of a liquid crystal display device used in Example 4 and a behavior of light used therein.

FIG. 19 is a diagram showing an overall view of a projection type liquid crystal display device.

FIG. 20 is a cross-sectional view showing an outline of the invention in this specification.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H048 BA02 BA45 BB02 BB10 BB14 BB28 BB37 BB44 2H091 FA02Y FA14Y FB08 FC02 FD06 GA03 GA13 GA16 LA12 LA30 2H092 GA17 HA04 JA24 JB13 NA07 PA08 PA12 5C094 AA05 AAA A42A BA16 BA43 CA19 CA24 DA12 DA13 DB01 DB04 DB10 EA04 EA05 EA06 EA07 EB02 EB04 EC03 ED03 ED11 ED13 ED14 ED15 ED20 FA01 FA02 FB01 FB02 FB12 FB15 FB16 GA10 GB10

Claims (12)

[Claims] A liquid crystal is sandwiched between a pair of substrates, and a pixel electrode made of a transparent conductive film arranged in a matrix on one of the pair of substrates, and a semiconductor element connected to the pixel electrode And a display device formed with
The liquid crystal display device according to claim 1, wherein the one substrate is a substrate having transparency and insulating properties, and the other substrate has a common electrode composed of a reflective layer and a transparent conductive film. 2. A pixel electrode comprising a transparent conductive film arranged in a matrix on one of the pair of substrates, wherein a liquid crystal is sandwiched between the pair of substrates, and a semiconductor element connected to the pixel electrode. And a display device formed with
The liquid crystal display device according to claim 1, wherein the one substrate is a substrate having transparency and insulation, and the other substrate has a common electrode including a reflective layer, a color filter layer, and a transparent conductive film. 3. The liquid crystal display device according to claim 2, wherein the color filter layer on the other substrate is formed above the reflective layer and below the common electrode. 4. The liquid crystal display device according to claim 2, wherein the color filter layer has an overcoat film made of an organic resin material after the color filter is formed. 5. The reflective layer according to claim 1, wherein the reflective layer is made of one selected from silver, a silver alloy, aluminum, and an aluminum alloy, or a combination thereof. Liquid crystal display device. 6. The liquid crystal display device according to claim 1, wherein the reflective layer on the other substrate and the transparent conductive film are electrically connected. 7. A liquid crystal display device according to claim 1, wherein said reflection layer is made of a dielectric multilayer film. 8. The method according to claim 1, wherein the reflection layer is a hologram (diffraction grating), silver, a silver alloy, aluminum, an aluminum alloy, a dielectric multilayer film,
A liquid crystal display device comprising one selected from dichroic mirrors or a combination thereof. 9. The liquid crystal display device according to claim 7, wherein the dielectric multilayer film of the reflection layer has a semi-transmission characteristic. 10. The reflective layer according to claim 1, wherein the reflective layer comprises a reflective film, an overcoat film,
A liquid crystal display device comprising one or both of an anchor coat film. 11. A liquid crystal display device according to claim 1, wherein a λ / 4 plate and a polarizing plate are arranged on the light incident surface of said one substrate. 12. A liquid crystal display device according to claim 1, wherein a λ / 4 plate, a scattering plate and a polarizing plate are arranged on the light incident surface of said one substrate. .