JP2002341366A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device which has superior color characteristics in either of cases wherein the device is used as a transmission type and a reflection type. SOLUTION: Each pixel area on the liquid-crystal side surface of one of substrates which are arranged opposite each other across liquid crystal has a reflection display area and a transmission display area, and an opening or cut is formed partially in the part of a color filter, formed in each pixel area on the liquid-crystal side surface of the other substrate, which faces the reflection display area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a so-called partial transmission type liquid crystal display device.

[0002]

2. Description of the Related Art A so-called partially transmissive liquid crystal display device is used, for example, as a small liquid crystal display device for a cellular phone, and is displayed by reflected light of the sun or light of a built-in backlight as necessary. It can recognize the image of the surface. That is, of the transparent substrates opposed to each other via the liquid crystal, one of the transparent substrates has a liquid crystal side surface on which a gate signal line extending in the x direction and juxtaposed in the y direction extends in the y direction. A region surrounded by drain signal lines that are arranged in parallel in the x direction is defined as a pixel region. Each of these pixel regions includes a thin film transistor driven by supply of a scanning signal from one of the gate signal lines, and a thin film transistor. And a pixel electrode to which a video signal from one drain signal line is supplied.

This pixel electrode is made of, for example, ITO (Indium-T
In-Oxide), an electric field is generated between the other transparent substrate on the liquid crystal side and a counter electrode composed of a transparent electrode commonly formed in each pixel area. Thereby, the light transmittance of the liquid crystal in the pixel region is controlled. In each of the pixel regions, a reflector made of, for example, a metal layer is formed in about half of the pixel region, thereby performing a reflective display in a portion (reflective display region) where the reflector is formed. To the portion where the reflection plate is not formed (transmissive display area)
Has a function of performing transmissive display.

The configuration of this type of liquid crystal display device is disclosed in, for example, Japanese Patent Application Laid-Open No. H11-101992,
-242226. And in such a liquid crystal display device, the one for color display is
Red (R), green (G), and blue (B) color filters are formed on the liquid crystal side surface of the other transparent substrate so as to face three adjacent pixel regions, for example.

[0005]

Here, a color filter in a partially transmissive liquid crystal display device is usually of a pale color whose color purity is reduced and transmittance is improved. When used as a reflection type, light passes through a color filter twice, so that attenuation of light at this time is reduced, and a display as bright as possible is obtained. However, it has been pointed out that when used as a transmissive type, light passes through a color filter only once, resulting in a whitish display with inferior color reproducibility as compared with a case where the type is used as a reflective type. If a color filter having excellent color reproducibility is used, the display when used as a reflection type becomes extremely dark, and is not practical.

As a countermeasure, it is conceivable to form a color filter having appropriate optical characteristics in correspondence with each of the reflective display area and the transmissive display area of each pixel area. Inconveniences such as a decrease in the alignment margin of the other transparent substrate with respect to the substrate occur. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid crystal display device which is excellent in color characteristics in both of a transmission type and a reflection type.

[0007]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows. Means 1. The liquid crystal display device according to the present invention has, for example, a reflective display area and a transmissive display area in each pixel area on a liquid crystal side surface of one of the substrates arranged to face each other with the liquid crystal interposed therebetween. An opening or a notch is provided in a part of a portion of the color filter formed in each pixel region on the liquid crystal side facing the reflective display region.

Means 2. The liquid crystal display device according to the present invention has, for example, a reflective display area and a transmissive display area in each pixel area on a liquid crystal side surface of one of the substrates arranged to face each other with the liquid crystal interposed therebetween. A color filter formed in each pixel area on a liquid crystal side surface, wherein an opening or notch is provided at an end of the color filter facing the reflective display area and far from the transmissive display area. It is.

Means 3. The liquid crystal display device according to the present invention has, for example, a reflective display area and a transmissive display area in each pixel area on a liquid crystal side surface of one of the substrates arranged to face each other with the liquid crystal interposed therebetween. A plurality of openings or notches scattered in a part of a portion of the color filter formed in each pixel region on the liquid crystal side facing the reflective display region are provided.

Means 4. The liquid crystal display device according to the present invention has, for example, a reflective display area and a transmissive display area in each pixel area on a liquid crystal side surface of one of the substrates arranged to face each other with the liquid crystal interposed therebetween. It is characterized in that a plurality of circular openings scattered are provided in a part of a portion of the color filter formed in each pixel region on the liquid crystal side facing the reflective display region.

Means 5. The liquid crystal display device according to the present invention has, for example, a rectangular shape surrounded by a pair of gate signal lines and a pair of drain signal lines formed on the liquid crystal side surface of one of the substrates disposed to face each other with the liquid crystal interposed therebetween. Of the three regions in the width direction, the central region is a reflective display region, the two side regions are transmissive display regions, and the other substrate has a liquid crystal side surface. In the formed color filter, an opening is formed in a central region of three regions divided in the width direction, and the opening is formed in a part of a region facing the reflective display region. It is characterized by having been done.

Means 6 The liquid crystal display device according to the present invention has, for example, a rectangular shape surrounded by a pair of gate signal lines and a pair of drain signal lines formed on the liquid crystal side surface of one of the substrates disposed to face each other with the liquid crystal interposed therebetween. Of the three regions in the width direction, the central region is a reflective display region, the two side regions are transmissive display regions, and the other substrate has a liquid crystal side surface. In the formed color filter, an opening is formed in a central region among three regions divided in the width direction, and the opening is formed in a region facing the reflective display region in the width direction. And a plurality of openings arranged side by side.

Means 7. The liquid crystal display device according to the present invention is based on, for example, the configuration of the means 1 to 6, and is characterized in that a resin film is formed so as to cover a color filter on a surface of the other substrate on the liquid crystal side. is there.

Means 8. In the liquid crystal display device according to the present invention, for example, the resin film is formed so as to fill the opening of the color filter formed on the liquid crystal side of the other substrate on the premise of the structure of the means 1 to means 6. It is characterized by having.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the liquid crystal display device according to the present invention will be described below with reference to the drawings. Embodiment 1 FIG. << Overall Configuration >> FIG. 2 is an equivalent circuit diagram showing an embodiment of the liquid crystal display device according to the present invention. Although the figure is a circuit diagram, it is drawn corresponding to an actual geometric arrangement. In the figure, there is a transparent substrate SUB1. This transparent substrate SU
B1 is arranged to face another transparent substrate (not shown) via the liquid crystal.

A gate signal line GL extending in the x direction and juxtaposed in the y direction in the drawing and a gate signal line GL extending in the y direction and extending in the x direction are provided at the center of the transparent substrate SUB1 except for the periphery of the liquid crystal side surface. Are formed in parallel with each other, and a region surrounded by each of the signal lines forms a pixel region. A large number of the pixel regions are arranged in a matrix to constitute a liquid crystal display region 13.

A storage capacitor electrode line CL extending in the x direction is formed between the gate signal line GL and another gate signal line GL adjacent to the gate signal line GL. Represents a capacitive element C described later in each pixel region.
One of the capacitance holding electrodes CT of the add is configured.

Each pixel region has one gate signal line GL
And a transparent pixel electrode PIX to which a video signal from one drain signal line DL is supplied via the thin film transistor TFT.
A storage capacitor Cadd is formed between X and the storage capacitor electrode line CL.

Each of the gate signal lines GL has a gate signal line driving circuit 15 composed of a semiconductor integrated circuit mounted on a transparent substrate SUB1 at both ends (left and right in the figure).
And the scanning signals output from the gate signal line driving circuit 15 are sequentially supplied.

Each of the drain signal lines DL has, at one end (lower side in the figure), a drain signal line drive circuit 1 composed of a semiconductor integrated circuit mounted on a transparent substrate SUB1.
4 so that a video signal is supplied in synchronization with the supply timing of the scanning signal.

Further, the storage capacitor electrode wiring CL has one end (left side in the figure) connected to a terminal Vcom. This terminal Vcom is connected to the transparent substrate S
Input terminals 18, 19, 100 formed around UB1
Are formed in parallel with each other, and are kept at the same potential as a transparent counter electrode (not shown) common to each pixel region on a liquid crystal side surface of another transparent substrate arranged to face the transparent substrate SUB1. It has become.

In the figure, reference numeral 16 denotes a precharge circuit for charging the drain signal line DL, and reference numeral 17 denotes a digital signal (control signal) input to the input terminals 19 and 100 by the gate signal line drive circuit 15 and the drain signal. This is a level shift circuit that sets a voltage sufficient to operate the signal line drive circuit 14.

<< Pixel Structure >> FIG. 3 is a plan view showing an embodiment of a pixel region of the liquid crystal display device according to the present invention, and its IV.
FIG. 4 shows a cross section taken along line -IV. FIG. 3 shows a configuration of one pixel region among the pixel regions constituting the liquid crystal display region 13 shown in FIG. 2. For this reason, in each pixel region in the left, right, up and down directions of this one pixel region. Has a similar configuration.

In FIG. 2, first, an underlayer SiO or SiN is formed on the liquid crystal side surface of the transparent substrate SUB1. The underlayer SiO is formed in order to prevent ionic impurities contained in the transparent substrate SUB1 from affecting a thin film transistor TFT described later. And
A semiconductor layer AS made of, for example, a polysilicon layer is formed on the surface of the underlayer SiO. The semiconductor layer AS is, for example, a polycrystalline amorphous Si film formed by a plasma CVD apparatus using an excimer laser.

The semiconductor layer AS includes a band-shaped portion formed adjacent to a gate signal line GL described later and a rectangular portion occupying almost half (upper side in the figure) of the pixel region integrally with this portion. Is formed. The band-shaped portion of the semiconductor layer AS is formed as a semiconductor layer of a thin film transistor TFT described later, and the rectangular portion of the semiconductor layer AS is formed as one electrode of a pair of electrodes of a capacitive element Cadd described later. I have.

On the surface of the transparent substrate SUB1 on which the semiconductor layer AS is formed, a first insulating film GI made of, for example, SiO2 or SiN is formed so as to cover the semiconductor layer AS. The first insulating film GI functions as a gate insulating film of the thin film transistor TFT, and is one of interlayer insulating films of a gate signal line GL and a drain signal line DL described later, and a capacitive element Ca described later.
It functions as one of the dd dielectric films. On the upper surface of the first insulating film GI, a gate signal line GL extending in the x direction in the figure and juxtaposed in the y direction is formed, and this gate signal line GL is connected to a drain signal line D described later.
Together with L, a rectangular pixel area is defined.

The gate signal line GL may be any conductive film having heat resistance, for example, Al, Cr, Ta,
TiW or the like is selected. In this embodiment, the gate signal line G
TiW is used as L. This gate signal line G
L is partially extended in the pixel region and overlapped so as to intersect with the band-shaped semiconductor layer AS. The extension GL of the gate signal line GL is a thin film transistor TFT
Is formed as the gate electrode GT.

After the formation of the gate signal line GL,
Ion implantation of impurities through the first insulating film GI,
By making the region of the semiconductor layer AS other than immediately below the gate electrode GT conductive, a source region and a drain region of the thin film transistor TFT are formed, and one of a pair of electrodes of the capacitor Cadd is formed. It is supposed to be.

On the upper surface of the first insulating film GI at the center of the pixel region, a storage capacitor electrode line CL extending in the x direction in the figure is formed. The storage capacitor electrode CT extending to the region is formed integrally. This storage capacitor electrode wiring C
L (storage capacitor electrode CT) is formed in the same layer and the same material as the gate signal line GL.

A second insulating film IN is formed of, for example, SiO2 or SiN on the upper surface of the first insulating film GI so as to cover the gate signal line GL and the storage capacitor electrode wiring CL (the storage capacitor electrode CT). Further, a metal film 10 made of, for example, aluminum (Al) is formed on the upper surface of the second insulating film IN so as to occupy almost half of the pixel region (upper region in the drawing).

The metal film 10 is formed on the thin film transistor T
In a portion near the FT, a contact hole CH1 formed in the second insulating film IN and the first insulating film GI is formed.
Through the semiconductor layer AS. Metal film 1
The semiconductor layer AS connected to 0 is a thin film transistor TFT
In contrast, the drain region of the thin film transistor TFT has a portion overlapped with the gate electrode GT and a region of the semiconductor layer AS on the opposite side through a contact hole CH2. To be connected to the drain signal line DL.
The metal film 10 extends to almost the center of the pixel so as to overlap the storage capacitor electrode CT.

That is, the metal film 10 constitutes a reflection plate for forming a reflection type pixel region, and also constitutes the other electrode of the capacitive element Cadd. The capacitance element Cadd is a thin film transistor TFT
Between the source region and the storage capacitor electrode CT, the first capacitor element having the storage capacitor electrode CT as one electrode, the rectangular semiconductor layer AS as the other electrode, and the first insulating film GI as a dielectric film And a two-stage capacitor in which the storage capacitor electrode CT is connected in parallel to one electrode, the metal film 10 is the other electrode, and the second capacitor is a second insulating film IN as a dielectric film. (See FIG. 1).

Further, on the upper surface of the second insulating layer IN, y in FIG.
A drain signal line DL extending in the direction and juxtaposed in the x direction is formed. The drain signal line DL defines a pixel region with the above-described gate signal line GL. The drain signal line DL is, for example, aluminum,
Aluminum having an underlying layer of TiW and aluminum having an underlying layer of MoSi are used. For example, when the aluminum is in direct contact with the polysilicon layer,
Since a conduction failure may occur at a process temperature of not less than ° C., it is effective to form the underlayer as described above.

A part of the drain signal line DL is the second
The thin film transistor TFT is connected to a drain region (a side connected to the drain signal line DL is defined as a drain region in this specification) through a contact hole CH2 formed in the insulating film IN and the first insulating film GI.

A third insulating film IN is formed on the upper surface of the second insulating film IN so as to cover the drain signal line DL and the metal film 10.
An insulating film PSV is formed. This third insulating film PSV
Is formed of, for example, SiO2 or SiN. However, an organic film may be formed by coating or the like. In the case of an organic film formed by coating or the like, the surface can be flattened, and the orientation of the liquid crystal can be made favorable.

The pixel electrode PIX made of, for example, an ITO (Indium-Tin-Oxide) film is formed on the upper surface of the third insulating film PSV.
Are formed. In this case, when the third insulating film PSV is formed of an organic film, the occurrence of pinholes generated in the film can be significantly suppressed, and therefore, when the third insulating film PSV is patterned for forming the pixel electrode PIX of the ITO film. There is an effect that damage to the metal film 10 can be prevented.

This pixel electrode PIX is a thin film transistor T
In the portion adjacent to the FT, the metal film 1 is passed through a contact hole CH3 formed in the third insulating film PSV.
0 is connected.

As a result, the pixel electrode PIX is connected to the source region of the thin film transistor TFT via the metal film 10, and when the thin film transistor TFT is turned on, the video signal from the drain signal line DL is applied to the thin film transistor TFT. It is supplied to the pixel electrode PIX via the TFT.

Here, the selectively formed intervening layer 1 is formed on the surface of the metal film 10 at the connection with the pixel electrode PIX.
1 is formed. The intervening layer 11 is formed by the metal film 1
When aluminum (Al) or the like is used as 0, for example, molybdenum silicon (MoS) is used because contact with the ITO film as the pixel electrode PIX is not good.
i) or formed by interposing a metal such as titanium tungsten (TiW).

In this case, the intervening layer 11 is preferably formed over the entire area of the metal film 10 from the viewpoint of the manufacturing process. In this embodiment, however, the intervening layer 11 is selectively formed within a certain range around the connection with the pixel electrode PIX. Is provided. The reason for this is that the metal film 10 functions as a reflection plate. Therefore, if the intervening layer 11 is formed over the entire area of the metal film 10, the light reflectance is usually reduced by the intervening layer 11. Because. Thus, a material having a high reflectance can be selected as the metal film 10, and a reliable connection with the pixel electrode PIX can be achieved.

In this embodiment, a conductive material made of the same material as that of the intervening layer 11 is formed so as to overlap the drain signal line DL. However, needless to say, it is not always necessary to form them.

The pixel electrode PIX is provided on each of the pixel regions on a liquid crystal side surface of another transparent substrate (not shown) opposed to the transparent substrate SUB1 on which the pixel electrode PIX is formed via a liquid crystal. An electric field is generated between the common counter electrode and the transparent counter electrode, and the light transmittance of the liquid crystal is controlled by the electric field.

In the liquid crystal display device thus configured, the metal film 10 functioning as a reflector does not directly contact the liquid crystal, and the third insulating film PSV is provided between the metal film 10 and the liquid crystal.
And a pixel electrode PIX made of a material that is not easily oxidized.

For this reason, since the metal film 10 has a configuration in which a battery action with liquid crystal interposed between other metals is unlikely to occur, it is possible to prevent the liquid crystal from being deteriorated due to the battery action. To play. The transparent substrate SUB1 configured as described above is arranged to face the transparent substrate SUB2 via the liquid crystal.

On the liquid crystal side surface of the transparent substrate SUB2, a black matrix is formed so as to define each pixel region. That is, at least the black matrix BM formed in the liquid crystal display unit 13 has a pattern in which an opening is formed in a region where a peripheral portion of each pixel region is left, thereby improving display contrast. Also,
The black matrix BM is formed so as to sufficiently cover the thin film transistor TFT on the transparent substrate SUB1 side.
By preventing irradiation of external light to the thin film transistor TFT, deterioration of characteristics of the thin film transistor TFT is avoided. The black matrix BM is formed of, for example, a resin film containing a black pigment.

On the surface of the transparent substrate SUB2 on which the black matrix BM is formed, a color filter FIL is formed so as to cover the opening of the black matrix BM. This color filter FIL includes, for example, red (R), green (G),
For example, a red filter is formed in common in each pixel region group arranged in the y direction, and a red (R) color is commonly formed in pixel region groups sequentially adjacent in the x direction. , Green (G), blue (B), red (R),.
It is formed in such an arrangement. Each of these color filters FIL is composed of a resin film containing a pigment corresponding to the color. Note that these color filters FI
L has an opening in a part thereof,
This will be described in more detail later.

On the surface of the transparent substrate SUB2 on which the black matrix BM and the color filter FIL are formed, the black matrix BM and the color filter FI are provided.
A flattening film OC is formed so as to cover L. The flattening film OC is formed of a resin film that can be formed by coating, and the black matrix BM and the color filter FIL are formed.
Is provided in order to eliminate a step that becomes apparent due to the formation of

On the upper surface of this flat film OC, for example, IT
A light-transmitting conductive film made of an O film is formed, and the conductive film forms a common counter electrode CT in each pixel region. An alignment film is formed on the surface of the flattening film OC. The alignment film is a film that directly contacts the liquid crystal, and the rubbing formed on the surface determines the initial alignment direction of the liquid crystal molecules. Is

<< Color Filter >> FIG. 1 is a plan view (transparent substrate SUB2) showing the structure of the color filter FIL.
FIG. FIG. 1 also shows one pixel region and a part of another pixel region adjacent thereto. The color filter FIL is formed to cover each opening of the black matrix BM formed so as to define each pixel region, and the same color filter is common to each pixel region arranged in the y direction. It has become. In the color filter FIL in the pixel region, an opening HL is provided in, for example, a center of a portion facing the reflector in the reflective display region. This opening HL
Is a rectangular shape having an outline at a portion that is approximately the same distance inward from the periphery of the reflective display area.

As a result, all of the light (light from the backlight) transmitted through the transmissive display area passes through the color filter FIL, and the light (external light such as sunlight) reflected on the reflective display area is reduced. Part of it is a color filter F
The light passes through the IL, and the remaining portion enters the eyes of the observer without passing through the color filter FIL.
In the liquid crystal display device configured as described above, by providing an opening in the color filter FIL formed in the reflective display area, the attenuation of light passing therethrough can be significantly reduced.

The light having a small attenuation as described above is combined with the light having a large attenuation that has passed through the color filter FIL, and is incident on the eyes of the observer as light having a small attenuation as a whole. For this reason, a bright and well-colored display is provided. By providing the opening HL of the color filter FIL substantially in the center of the reflective display area, a part of the opening HL faces the transmissive display area due to misalignment between the transparent substrate SUB1 and the transparent substrate SUB2. The arrangement can be avoided.

Embodiment 2 FIG. FIG. 5 is a configuration diagram showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. In the above-described embodiment, the color filter FI
The opening formed in L is formed so as to be positioned substantially at the center of the reflective display area. But,
As shown in FIG. 5, it may be formed so as to be located far from the transmissive display area and at the end of the reflective area. In this case, even if the misalignment between the transparent substrate SUB1 and the transparent substrate SUB2 occurs, the light transmitted through the transmissive display area surely passes through the color filter FIL without passing through the opening of the color filter FIL. It can be configured as follows.

Embodiment 3 FIG. FIG. 6 is a configuration diagram showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. In the figure, the pixel region is divided into three regions having a boundary in the y direction, for example, a central region is a reflective display region, and each region on both sides is a transmissive display region.

The color filter FIL is also divided into three regions having boundaries in the y direction, and the central region is defined as an opening. In this case, the width of the opening is set to be smaller than the width of the reflective display area.
Light mixed with light passing through the IL and light not passing through the color filter FIL (light passing through the opening) can be recognized.

In this case, the color filter FI
The opening of L has an elongated shape and can be configured to have a very small width. This means that the color filter F
The level difference due to the opening can be significantly reduced by forming the flattening film OC on the surface where the IL is formed, which means that the thickness of the liquid crystal can be made uniform.

The layer thickness of the liquid crystal has a sensitive influence on the display performance, and if the thickness is not uniform, display unevenness with different contrast depending on the place occurs. When an opening is formed in the color filter FIL, a step corresponding to the thickness of the color filter FIL usually occurs, and a portion having a different liquid crystal layer thickness occurs in one pixel region. Therefore, the contrast is reduced as compared with the case where there is no opening.

Display mode utilizing the birefringence effect of liquid crystal,
For example, in the case of a single-polarizer twisted nematic display mode used for a reflection type display, it is sensitive to the thickness of the liquid crystal,
If the thickness fluctuates from the optimum value, the contrast is reduced.

Embodiment 4 FIG. FIG. 7 is a block diagram showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. The opening HL formed in the color filter FIL is divided into a plurality of portions in the short side direction, thereby further reducing the width of each opening significantly. It is like that.

Embodiment 5 FIG. FIG. 8 is a configuration diagram showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. In the figure, the opening HL formed in the color filter FIL is not formed in a band shape but in a rectangular shape scattered in a plurality of matrices. Opening H
By increasing the number of L, their diameter can be reduced, and the influence of the step can be greatly reduced by the flattening film OC formed on the upper surface.

Embodiment 6 FIG. FIG. 9 is a block diagram showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. In the figure, the openings formed in the color filter FIL have a circular shape scattered in a plurality of matrices.

Embodiment 7 FIG. In the above-described embodiment, the flattening film OC is formed by covering the surface of the transparent substrate SUB2 with the color filter FIL. However, the present invention is not limited to this. The openings HL may be selectively formed so as to fill the openings HL only in the portions HL.

Embodiment 8 FIG. FIG. 10 is a configuration diagram showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. The configuration different from that of FIG.
Without making the shape of the opening HL of the IL into an elongated strip shape,
A part of the reflective display area has a shape close to a square. In this case, the length of the periphery of the opening HL can be reduced. In the periphery of the opening HL of the color filter FIL, the alignment of the liquid crystal is likely to be disturbed due to a step in that portion, and this causes a decrease in contrast. Since the degree of the decrease in contrast depends on the length of the periphery of the opening HL, when the opening HL having the same area is formed, the opening is formed to have a substantially rectangular shape, so that the In this case, the region where the alignment disorder is generated is made as small as possible.

Embodiment 9 FIG. FIG. 11 is a configuration diagram showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. This figure shows that, in the pixel region, a transmissive display region is formed in a central portion excluding the periphery, a reflective display region is formed in the periphery, and an opening of the color filter FIL is formed at an end of the reflective display region. is there.

Embodiment 10 FIG. In each of the embodiments described above, the case where the black matrix BM is provided has been described. However, this black matrix BM
Need not be formed.

The transparent substrate SUB with respect to the transparent substrate SUB1
If the two can be accurately aligned, the transparent substrate S
This is because the gate signal line GL and the drain signal line DL formed on the UB1 side can also serve the function of the black matrix BM. However, there is a concern that the reflection of light by these signal lines lowers the contrast in reflective display.

For this reason, as shown in FIG. 3 (FIG. 4), the MoSi formed on the surface of the drain signal line DL is formed.
Alternatively, a configuration covered with a barrier metal such as TiW has a reflectance that is about half that of Al used as a reflective electrode, and thus is extremely effective without the above-described inconvenience. In addition,
In the case of the gate signal line GL, as shown in FIG. 3, by forming itself with TiW or the like, the above-described inconvenience can be eliminated.

FIG. 12 is a plan view showing the configuration when the black matrix BM is not formed, based on the configuration shown in FIG. A region between the color filter FIL and another color filter FIL adjacent to the color filter FIL is arranged so as to face the drain signal line DL, and the drain signal line DL also has the function of the black matrix BM. .

FIG. 13 is a diagram showing a configuration in the case where the black matrix BM is not formed on the premise that the central portion excluding the periphery of the pixel region is a reflective display region and the periphery is a transmissive display region. is there. In this case, the color filter F
The opening portion HL of the IL may be formed in a part of the portion facing the reflective display region, but in the same figure, it is formed to be elongated at substantially the center of the pixel region along the direction of the drain signal line DL. ing. Further, the opening HL of the color filter FIL in FIG. 13 may have a shape connected in the direction of the drain signal line DL.

Embodiment 11 FIG. In each of the above-described embodiments, the semiconductor layer A of the thin film transistor TFT formed in each pixel region is used.
S uses polycrystalline silicon (p-Si).
However, it goes without saying that the present invention is also applicable to those using amorphous silicon (a-Si).

FIG. 14 is a diagram showing a configuration of a pixel of a liquid crystal display device provided with a thin film transistor TFT made of a-Si. FIG. 1 shows three pixel regions which are one pixel of a color display. FIG. 15 shows a cross section taken along line XV-XV in FIG.

In each figure, a pair of gate signal lines GL extending in the x direction and juxtaposed in the y direction are formed on the surface of the transparent substrate SUB1 on the liquid crystal side. The gate signal line GL is made of, for example, Al (aluminum), and has an anodic oxide film AOF formed on the surface thereof. These gate signal lines GL surround a rectangular area together with a pair of drain signal lines DL described later, and this area is configured as a pixel area.

Then, for example, ITO (Indium-Tin-Oxid) is provided at the center of the pixel region except for a slight periphery.
e) Transparent pixel electrode (first pixel electrode) PX such as a film
1 is formed. The pixel electrode PX1 functions as a pixel electrode in a region (transmissive display region) of the pixel region through which light from the backlight BL can pass, and a pixel electrode (second pixel electrode) PX that also serves as a reflective electrode described later.
2 is distinguished.

As described above, the gate signal line GL and the pixel electrode P
On the surface of the transparent substrate SUB1 on which X1 is formed, an insulating film GI made of, for example, SiN (silicon nitride) is formed. The insulating film GI is formed over a region where the thin film transistor TFT is formed (part of the gate signal line GL) and an intersection between the gate signal line GL and the drain signal line DL in the vicinity thereof.

The insulating film GI formed in the region where the thin film transistor TFT is formed functions as a gate insulating film of the thin film transistor TFT, and the insulating film GI formed at the intersection of the gate signal line GL and the drain signal line DL serves as an interlayer. It has a function as an insulating film.

Then, a semiconductor layer AS made of amorphous Si (silicon) is formed on the surface of the insulating film. This semiconductor layer AS is that of the thin film transistor TFT and has a drain electrode SD on its upper surface.
By forming the gate electrode 1 and the source electrode SD2, an MIS transistor having an inverted staggered structure in which a part of the gate signal line GL is used as a gate electrode can be formed.

The semiconductor layer AS has a gate signal line G
L is also formed to extend to the intersection with the drain signal line DL, thereby enhancing the function of each signal line as an interlayer insulating film together with the insulating film GI.

Although not clarified in FIG. 15,
The drain electrode SD on the surface of the semiconductor layer AS;
A semiconductor layer doped with a high-concentration impurity (for example, phosphorus) is formed at the interface between the semiconductor layer 1 and the source electrode SD2, and this semiconductor layer constitutes a contact layer d0. The drain electrode SD1 and the source electrode SD2 are formed simultaneously, for example, when the drain signal line DL is formed.

That is, a drain signal line DL extending in the y-direction and juxtaposed in the x-direction is formed, a part of which extends to the upper surface of the semiconductor layer AS to form a drain electrode SD.
1 is formed, and a source electrode SD2 is formed to be separated from the drain electrode SD1 by the channel length of the thin film transistor TFT. This drain signal line DL
Is composed of, for example, a sequentially laminated body of Cr and Al.

The source electrode SD2 extends slightly from the surface of the semiconductor layer AS to the pixel region side to achieve an electrical connection with the pixel electrode PX1, and a connection with a pixel electrode PX2 also serving as a reflective electrode described later. A contact portion for achieving the above is formed.

Here, the extending portion of the source electrode SD2 not only has a function of achieving connection with the pixel electrodes PX1 and PX2 as described above, but also has a reflective display area (where a pixel electrode PX2 described later is formed). Area)
The pixel electrode PX2 is formed so as to extend to most of the reflective display area so that a height difference due to a step is not large.

That is, when the extending portion of the source electrode SD2 only has a function of establishing connection with the pixel electrodes PX1 and PX2, the extending portion may be formed as a contact portion. Is also relatively short. Then, a step around the extending portion becomes apparent on a surface (upper surface of a protective film PSV described later) forming a pixel electrode PX2 also serving as a reflective electrode described later, and a step is also formed on the surface of the pixel electrode PX2. Will be.

Further, with the configuration as in this embodiment, the extending portion of the source electrode SD2 occupies a relatively large area, which means that its side is relatively long. . Therefore, in the manufacture of the liquid crystal display device, impurities such as dust hardly remain in the vicinity of the pixel electrode PX2, and the adverse effects due to the impurities can be removed.

By the way, in the case of the source electrode of the thin film transistor TFT having a function as a contact portion, the area of the contact portion is small, and the sides thereof are formed slightly complicated by selective etching by the photolithography technique, and impurities such as dusts are formed there. Often remains and impairs the function as a contact portion.

On the surface of the transparent substrate SUB1 on which the drain signal line DL, the drain electrode SD1 and the source electrode SD2 of the thin film transistor TFT are formed, a protective film PSV made of, for example, SiN is formed. The protective film PSV is a layer for avoiding direct contact of the thin film transistor TFT with the liquid crystal.
This is intended to prevent the deterioration of the characteristics.

A contact hole CH is formed in the protective film PSV, and a part of the source electrode SD2 of the thin film transistor TFT is exposed in the contact hole CH. On the upper surface of the protective film PSV, a pixel electrode PX2 also serving as a reflective electrode is formed. The pixel electrode PX2 is formed of a non-light-transmitting conductive film made of, for example, a sequentially laminated body of Cr and Al.

The pixel electrode PX2 is formed so as to occupy most of the pixel region while avoiding the region serving as the light transmitting portion. Part of the pixel electrode PX2 is formed of the protective film P.
It is electrically connected to the source electrode SD2 of the thin film transistor TFT through a contact hole CH formed in a part of the SV. The pixel electrode PX2 is formed so as to extend until it overlaps with another adjacent gate signal line GL different from the gate signal line GL for driving the thin film transistor TFT.
A capacitance element Cadd using SV as a dielectric film is formed.

Then, an alignment film (not shown) is formed on the upper surface of the transparent substrate SUB1 on which the pixel electrode PX2 is formed so as to cover the pixel electrode PX2 and the like. This alignment film is a film that directly contacts the liquid crystal LC, and determines the initial alignment direction of the molecules of the liquid crystal by rubbing formed on the surface thereof.

The transparent substrate SUB1 constructed as described above
In addition, a transparent substrate SUB2 is disposed to face through a liquid crystal LC, and a black matrix BM is formed on the liquid crystal side surface of the transparent substrate SUB2 so as to define each pixel region. That is, at least the black matrix BM formed in the liquid crystal display part AR forms a pattern in which an opening is formed in a region that leaves the peripheral portion of each pixel region, thereby improving display contrast.

The black matrix BM is formed so as to sufficiently cover the thin film transistor TFT on the transparent substrate SUB1 side, and prevents the thin film transistor TF from being irradiated with external light.
The characteristic deterioration of T is avoided. The black matrix BM is formed of, for example, a resin film containing a black pigment.

A color filter FIL is formed on the surface of the transparent substrate SUB2 on which the black matrix BM is formed so as to cover the opening of the black matrix BM. This color filter includes, for example, filters of red (R), green (G), and blue (B). For example, a red filter is commonly formed in each pixel region group arranged in the y direction. Red (R), green (G), blue (B), and red (R) colors are common to the pixel region groups sequentially adjacent to the region group in the x direction.
It is formed in an array of colors,. Each of these filters is composed of a resin film containing a pigment corresponding to the color.

Here, in this embodiment, the color filter FIL has an opening HL in a part of each pixel area facing the reflective display area. In this case, the opening HL has, for example, a rectangular shape extending in the width direction (x direction) of the pixel region, and is positioned substantially at the center of the reflective display region. In such a case, even if the misalignment of the transparent substrate SUB1 and the transparent substrate SUB2 in the y direction occurs, a part of the opening HL does not face the transmissive display area.

Although the provision of the openings HL in the color filter FI hinders the uniformity of the liquid crystal layer thickness as described above, the structure in which the steps are sufficiently eliminated on the transparent substrate SUB1 side as described above. Therefore, it can be suppressed to a range where there is virtually no adverse effect. Further, the opening HL formed in the color filter FIL does not need to be formed in this manner, and may be formed as described in each of the above-described embodiments.

On the surface of the transparent substrate SUB2 on which the black matrix BM and the color filter FIL are formed, the black matrix BM and the color filter FI are provided.
A flattening film OC is formed so as to cover L. The flattening film OC is formed of a resin film that can be formed by coating, and the black matrix BM and the color filter FIL are formed.
Is provided in order to eliminate a step that becomes apparent due to the formation of

On the upper surface of this flat film OC, for example, IT
A light-transmitting conductive film made of an O film is formed, and the conductive film forms a common counter electrode CT in each pixel region. An alignment film (not shown) is formed on the surface of the flattening film OC. The alignment film is a film directly in contact with the liquid crystal LC, and the initial alignment direction of the liquid crystal molecules is formed by rubbing formed on the surface. Is determined

[0095]

As is apparent from the above description,
According to the liquid crystal display device of the present invention, it is possible to obtain a liquid crystal display device having excellent color characteristics even when used as a transmission type or a reflection type. Further, the opening of the color filter can be formed so as to face a part of the reflective display region even when one substrate and the other substrate are misaligned.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating an embodiment of a pixel of a liquid crystal display device according to the present invention, and is a plan view illustrating an embodiment of a configuration of a color filter in a pixel region having a reflective display region and a transmissive display region.

FIG. 2 is an equivalent circuit diagram showing one embodiment of a liquid crystal display device according to the present invention.

FIG. 3 is a plan view showing one embodiment of a pixel on one substrate side of the liquid crystal display device according to the present invention.

FIG. 4 is a view showing a cross section taken along line IV-IV of FIG. 3;

FIG. 5 is a plan view showing one embodiment of a pixel of the liquid crystal display device according to the present invention.

FIG. 6 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

FIG. 7 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

FIG. 8 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

FIG. 9 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

FIG. 10 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

FIG. 11 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

FIG. 12 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

FIG. 13 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

FIG. 14 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

15 is a sectional view taken along line XV-XV in FIG.

[Explanation of symbols]

SUB1: transparent substrate, AS: semiconductor layer, GL: gate signal line, DL: drain signal line, CL: storage capacitor electrode wiring, TFT: thin film transistor TFT, Cadd: storage capacitor element, PIX: pixel electrode, 10: metal layer ( reflector,
FIL ... color filter, H
L: Opening.

Continuing from the front page (72) Inventor Toshio Miyazawa 3300 Hayano, Mobara-shi, Chiba Prefecture Hitachi Display Co., Ltd. (72) Inventor Masataka Okamoto 3681-Hayano, Mobara-shi, Chiba Hitachi Device Engineering Co., Ltd. (72) Inventor Hiroaki Asuma 3300 Hayano, Mobara-shi, Chiba Pref. In Hitachi Display Group (72) Inventor Koichi Abu 3300-Hayano, Mobara-shi, Chiba F-term in Hitachi Display Group, Inc. 2H090 HA03 HD05 HD06 HD06 LA01 LA15 LA20 2H091 FA02Y FA14Y FA41Z FD24 GA02 GA03 GA16 LA15 2H092 GA60 JA24 JB07 JB21 JB31 JB52 JB57 JB58 JB61 KB14 NA01 PA08 PA12

Claims (8)

[Claims] 1. A liquid crystal display device comprising: a first substrate having a reflective display region and a transmissive display region in each pixel region on a liquid crystal side of one of substrates opposed to each other via a liquid crystal; A liquid crystal display device, wherein an opening or a notch is provided in a part of a portion of the color filter formed in each pixel region facing the reflective display region. 2. A liquid crystal display device, comprising: a substrate having a reflective display area and a transmissive display area in each pixel area on a liquid crystal side of one of the substrates opposed to each other with a liquid crystal interposed therebetween; A liquid crystal display device comprising a color filter formed in each pixel region, wherein an opening or a notch is provided at a portion facing the reflective display region and far from the transmissive display region. 3. A reflective display area and a transmissive display area are provided in each pixel area on a liquid crystal side surface of one of the substrates opposed to each other via a liquid crystal, and the other substrate has a liquid crystal side surface. A liquid crystal display device comprising a plurality of openings or notches scattered in a part of a portion of a color filter formed in each pixel region facing the reflective display region. 4. A reflective display area and a transmissive display area are provided in each pixel area on a liquid crystal side surface of one of the substrates opposed to each other with a liquid crystal interposed therebetween, and the other substrate has a liquid crystal side surface. A liquid crystal display device comprising a plurality of circular openings scattered in a part of a portion of a color filter formed in each pixel region facing the reflective display region. 5. A rectangular pixel area surrounded by a pair of gate signal lines and a pair of drain signal lines formed on a liquid crystal side surface of one of the substrates opposed to each other with a liquid crystal interposed therebetween. The central region of the three regions divided in the width direction is a reflective display region, the regions on both sides are transmissive display regions, and a color filter formed on the liquid crystal side surface of the other substrate. Preferably, an opening is formed in a central region of the three regions divided in the width direction, and the opening is formed in a part of a region facing the reflective display region. Characteristic liquid crystal display device. 6. A rectangular pixel region surrounded by a pair of gate signal lines and a pair of drain signal lines formed on a liquid crystal side surface of one of the substrates opposed to each other with a liquid crystal interposed therebetween. The central region of the three regions divided in the width direction is a reflective display region, the regions on both sides are transmissive display regions, and a color filter formed on the liquid crystal side surface of the other substrate. An opening is formed in a central region of the three regions divided in the width direction, and the opening is arranged in the width direction in a region facing the reflective display region. A liquid crystal display device comprising a plurality of openings. 7. The liquid crystal display device according to claim 1, wherein a resin film is formed so as to cover a color filter on a surface of the other substrate on a liquid crystal side. 8. The resin film according to claim 1, wherein a resin film is formed so as to fill the opening of the color filter formed on the liquid crystal side of the other substrate. 3. The liquid crystal display device according to 1.