JP2003107455A - Liquid crystal display device and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device with enhanced reliability of its reflection electrode, brightness, and manufacturing yield. SOLUTION: In the liquid crystal display device which has a couple of transparent substrates placed opposite to each other with a liquid crystal layer inbetween, and on one of the substrates, a plurality of scanning wires, a plurality of signal wires crossing the scanning wires, and thin film transistors in the vicinity of each crossing are provided, which has a protection film formed to cover the thin film transistors and the signal wires, and a pixel electrode formed by being connected to the source electrodes of the thin film transistors thereon and in which the pixel electrode is made of a material with a high light reflection efficiency with respect to an incident light from the surface, linear minute recessed parts or projections regularly laid out and recessed parts or projections irregularly laid out over the linear recessed parts or projections, are formed in a protection film under the pixel electrode.

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 thin film transistor (TFT) having a reflective electrode.
The present invention relates to an active matrix type liquid crystal display device such as a display system and a manufacturing method thereof.

[0002]

2. Description of the Related Art A liquid crystal display device is a transmissive liquid crystal display device that displays an image by switching transmission and blocking of light from a backlight by a liquid crystal panel and a reflective liquid crystal device that reflects and uses light incident from the surroundings. There is a display device.

Since the transmissive liquid crystal display device has the drawback that the power consumption of the backlight is large and the visibility is deteriorated by external light, it is not the best as a display device for a portable information terminal mainly used outdoors.

On the other hand, the reflection type liquid crystal display device is widely used as a display device for portable information terminals because it has low power consumption and is thin and lightweight.

In order to improve brightness and contrast, minute irregularities are irregularly formed on the surface of the reflective electrode of the reflective liquid crystal display device so as to enhance the reflection efficiency of external light. It is disclosed in JP-A-6-75238.

The fine irregularities are formed of resin under the reflective electrode for ease of shape control.

[0007]

However, the adhesion between the resin and the metal is weak, and the reflective electrode is partially peeled off from the resin, which causes a problem of reduction in reflection efficiency.

It is expected that the adhesiveness between the resin and the metal will be improved by increasing the density of the irregularities, but there is a limitation that irregularities should be arranged irregularly in order to improve the scattering characteristics of the incident light, and the adhesion is enhanced. Not enough.

An object of the present invention is to solve the above-mentioned problems of the prior art, and the resin and metal are strongly adhered to each other in the reflective pixel electrode portion,
Another object of the present invention is to provide a liquid crystal display device using an electrode that reflects external light without being reflected, and a manufacturing method thereof.

[0010]

The typical means for solving the problems provided by the present application are as follows.

(Means 1) A transparent substrate and another substrate which is arranged to face the transparent substrate with a liquid crystal layer interposed therebetween, and a plurality of scanning wirings on the other substrate and a direction intersecting the scanning wirings. A plurality of signal wirings wired to each other, a thin film transistor provided near each intersection thereof, a protective film formed to cover the thin film transistor and the signal wiring, and a source of the thin film transistor formed on the protective film. In a liquid crystal display device having a pixel electrode electrically connected to an electrode, the pixel electrode being formed of a material having light reflectivity, a plurality of thin lines are formed in a region of the protective film below the pixel electrode. -Shaped recesses or protrusions are formed in the first region, and a second region is formed between the first region is formed in the recesses or protrusions, a thin line in the first region Concave or convex The width is almost regular, the width of the second region is larger than the regular width.

(Means 2) A transparent substrate and another substrate which is arranged to face the transparent substrate with a liquid crystal layer interposed therebetween, and a plurality of scanning wirings on the other substrate, and a direction intersecting the scanning wirings. A plurality of signal wirings wired to each other, a thin film transistor provided near each intersection thereof, a protective film formed to cover the thin film transistor and the signal wiring, and a source of the thin film transistor formed on the protective film. In a liquid crystal display device having a pixel electrode electrically connected to an electrode, the pixel electrode being formed of a material having light reflectivity, a plurality of thin lines are formed in a region of the protective film below the pixel electrode. Area having a concave or convex shape and a second area having a concave or convex portion extending between the first areas, and a thin linear shape in the first area. Concave or convex The width of the parts is approximately regular and the second regions are arranged irregularly.

(Means 3) A transparent substrate and another substrate which is arranged to face the transparent substrate with a liquid crystal layer interposed therebetween, and a plurality of scanning wirings on the other substrate and a direction intersecting the scanning wirings. A plurality of signal wirings wired to each other, a thin film transistor provided near each intersection thereof, a protective film formed to cover the thin film transistor and the signal wiring, and a source of the thin film transistor formed on the protective film. In a liquid crystal display device having a pixel electrode electrically connected to an electrode through a contact hole, at least a part of the contact hole has a wavy shape when seen in a plan view.

Further, the means 3 has a plurality of linear concave portions or convex portions substantially regularly arranged in a region of the protective film below the pixel electrode, and the corrugated shape has a plurality of linear shapes. It has a regularity similar to that of the concave portion or the convex portion.

Further, in the means 3 or 4, the corrugated shape is formed on or adjacent to an extension line of the plurality of linear recesses or projections which are substantially regularly arranged.

Further, in the means 1 to 5, the spacing between the substantially regularly arranged linear concave portions or convex portions is 50.
Arrange so that the error is within%.

Further, in the means 1 to 5, the interval between the linear concaves or convexes arranged substantially regularly is 10
Arrange so that the error is within%.

Further, in the means 1 to 5, the period of the linear recesses or protrusions arranged substantially regularly is 1 μm.
It is arranged so as to be from m to 6 μm.

Further, the means 1 to 5 are arranged such that the depth of the concave portions or the height of the convex portions which are substantially regularly arranged is 0.001 μm to 1 μm.

(Means 4) A step of applying a photosensitive resin and exposing the resin using a mask in which linear light-shielding patterns and linear opening patterns are regularly arranged, and dot- or band-shaped light-shielding There is a step of exposing the resin using a mask in which patterns are irregularly arranged, and the resin is developed with an alkaline solution to form a pattern.

(Means 5) A photosensitive resin is applied, and a mask having regularly arranged linear light-shielding patterns and linear opening patterns and irregularly arranged dots or strip-shaped light-shielding patterns is used. To expose the resin, and then develop the resin with an alkaline solution to form a pattern.

According to the present invention, it is possible to improve the adhesion strength between the pixel electrode and the protective film, realize a liquid crystal display device having high reliability and high reflectance. Further, by having both the regular portion and the irregular portion, it is possible to realize a liquid crystal display device having an electrode that further reflects external light without being reflected.

Further, since the contact hole portion has a corrugated shape, even if peeling stress occurs on one side of the contact hole due to stress, it is possible to prevent the stress from spreading to the entire side, so that the rate of connection failure is greatly reduced. Thus, a liquid crystal display device having high reliability can be realized.

Further means of the invention will be apparent in the following description.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a liquid crystal display device and a manufacturing method thereof according to the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is an overall equivalent circuit diagram showing one embodiment of a liquid crystal display device according to the present invention. Although the figure is an equivalent circuit, it is drawn corresponding to the actual geometrical arrangement.

In FIG. 1, there is a pair of transparent substrates SUB1 and SUB2 arranged to face each other with a liquid crystal interposed therebetween, and the liquid crystal is enclosed by a seal material SE which also fixes one transparent substrate SUB1 to the other transparent substrate SUB2. ing.

On the liquid crystal side surface of the one transparent substrate SUB1 surrounded by the sealing material SE, the gate signal line GL extending in the X direction and provided in the Y direction and the X direction extending in the Y direction. And a drain signal line DL attached to the.

Each gate signal line GL and each drain signal line D
The region surrounded by L and L constitutes a pixel region, and the matrix-shaped aggregate of these pixel regions is the liquid crystal display unit A.
It constitutes R.

Each pixel region is provided with a thin film transistor TFT operated by a scanning signal from the gate signal line GL on one side and a pixel electrode to which a video signal from the drain signal line DL on one side is supplied via the thin film transistor TFT. PX1 is formed.

This pixel electrode PX1 is a transparent substrate SUB2.
An electric field is generated between the counter transparent electrode PX2 formed above and the light transmittance of the liquid crystal is controlled by this electric field.

One end of each of the gate signal lines GL extends beyond the sealing material SE, and the extended end constitutes a terminal to which the output terminal of the vertical signal drive circuit V is connected. There is.

Further, a signal from a printed circuit board arranged outside the liquid crystal display panel is inputted to an input terminal of the vertical scanning drive circuit V.

The vertical scanning drive circuit V comprises a plurality of semiconductor devices, a plurality of gate signal lines GL adjacent to each other are grouped, and one semiconductor device is assigned to each group. .

Similarly, one end of each of the drain signal lines DL extends beyond the sealing material SE, and the extended end constitutes a terminal to which the output terminal of the video signal driving circuit He is connected. Has become.

The input terminal of the video signal drive circuit He is adapted to receive a signal from a printed circuit board arranged outside the liquid crystal display panel.

The video signal driving circuit He is also composed of a plurality of semiconductor devices, and a plurality of drain signal lines DL adjacent to each other are grouped, and one semiconductor device is assigned to each group. There is.

One of the gate signal lines GL is sequentially selected by the scanning signal from the vertical scanning circuit V.

A video signal is supplied to each of the drain signal lines DL by a video signal drive circuit He at the timing of selecting the gate signal line GL.

FIG. 2 is a plan view showing the structure in the pixel region (the unevenness on the surface of the pixel electrode PX1 is not shown), and FIG. 3 and BB are sectional views taken along line AA of FIG.
A cross-sectional view taken along the line is shown in FIG.

As for the sectional structure of the region RE1 in FIG. 3 and the region RE2 in FIG. 4, the same sectional structure can be obtained as long as it is within the region RE shown in FIG. 2, and the line A--A or B-- shown in FIG. The sectional view is not limited to the line B.

On the surface of the transparent substrate SUB1 on the liquid crystal side, first, X
A pair of gate signal lines GL (one of which is not shown) extending in the Y direction and arranged side by side in the Y direction is formed.

These gate signal lines GL surround a rectangular area together with a pair of drain signal lines (one of which is not shown) described later, and this area is configured as a pixel area.

An insulating film GI made of, for example, SiN is formed on the SUB surface of the transparent substrate on which the gate signal line GL is formed in such a manner as to cover the gate signal line GL.

The insulating film GI functions as an interlayer insulating film for the gate signal line GL in the formation region of the drain signal line DL described later, and functions as a gate insulation film in the formation region of the thin film transistor TFT described later. In the formation area of the capacitive element Cadd, which will be described later, the piezoelectric element functions as a dielectric.

On the surface of this insulating film GI,
A semiconductor layer AS made of, for example, amorphous Si is formed so as to overlap a part of the gate signal line GL.

The semiconductor layer AS may be polycrystalline Si.

This semiconductor layer AS is a thin film transistor T.
By forming the drain electrode SD1 and the source electrode SD2 on the upper surface of the FT, the MIS having the inverted stagger structure in which a part of the gate signal line GL is used as the gate electrode.
Type transistors can be constructed.

Here, the drain electrode SD1 and the source electrode SD2 are formed at the same time when the drain signal line DL is formed.

That is, a drain signal line extending in the Y direction is formed, a part of which extends to the upper surface of the semiconductor layer AS to form the drain electrode SD1.
A source electrode SD2 is formed apart from the drain electrode SD1 by the channel length of the thin film transistor TFT.

The source electrode SD2 slightly extends from the surface of the semiconductor layer AS to the upper surface of the insulating film GI on the pixel region side, and a contact portion for connecting to a pixel electrode PX described later is formed.

The semiconductor layer AS and the drain electrode SD1
A thin layer doped with a high concentration of impurities is formed at the interface with the source electrode SD2, and this layer functions as a contact layer.

A high-concentration impurity layer is already formed on the surface of the contact layer when the semiconductor AS layer is formed, and the contact layer is exposed by using the pattern of the drain electrode SD1 and the source electrode SD2 formed on the upper surface as a mask. It can be formed by etching the formed impurities.

As described above, the protective film PC is formed on the surface of the transparent substrate on which the thin film transistor TFT, the drain signal line DL, the drain electrode SD1 and the source electrode SD2 are formed.

In this case, the protective film PC plays a role of avoiding direct contact of the thin film transistor TFT with the liquid crystal LC and preventing characteristic deterioration of the thin film transistor TFT.

Further, silicon nitride (SiNx) is provided between the semiconductor layer AS of the thin film transistor TFT and the protective film PC.
By forming the inorganic insulating film made of, it is possible to improve the reliability of preventing the characteristic deterioration of the thin film transistor TFT.

Further, the protective film PC is a pixel electrode P which will be described later.
It is a base of X1 and serves as a layer for forming irregularities on the surface of the pixel electrode PX1.

Further, in the present invention, the positive type photosensitive polymer resin is used for the protective film PC, but the unevenness can be formed also by using the negative type photosensitive polymer resin.

FIG. 5 is a plan view of a mask for forming irregularities on the surface of the protective film PC used in the present invention.
6 is a sectional view taken along the line D and FIG. 7 is a sectional view taken along the line D-D in FIG.

The cross-sectional structure of the region RE3 in FIG. 6 and the region RE4 in FIG. 7 is the same as the light-shielding pattern SH shown in FIG.
A similar cross-sectional structure can be obtained within the region surrounded by 3.
The sectional view is not limited to the line CC or the line DD shown in FIG.

In FIG. 6, the light shielding pattern SH is formed on the mask substrate QU with a material having a low light transmittance, such as chromium (Cr).
Is formed by. Opening pattern KA1 and opening pattern C
HX represents a portion where there is no chrome on the mask substrate QU.

In the masked area RE3, the width W1 of the linear light-shielding pattern SH1 and the width D of the linear opening pattern KA1.
They are regularly arranged in the cycle of the sum LX of 1.

Further, in this embodiment, the LX is set to 2 μm.

On the other hand, in FIG. 7, the light-shielding pattern SH2 formed on the mask substrate QU is a masked region RE.
In No. 4, they are arranged irregularly.

The light-shielding pattern SH2 in this case is preferably circular in plan view, but may be polygonal such as quadrangle or octagon.

The opening pattern CHX formed on the mask substrate QU is a pattern for forming a contact hole CH that electrically connects the pixel electrode PX1 and the source electrode SD2 of the thin film transistor TFT described later. In the figure, in order to facilitate understanding, the opening pattern C
Although HX is hatched, it is a region through which light is transmitted like the opening pattern KA1.

A protective film PC which allows the mask as described above to pass therethrough.
Exposure of light irradiated to, in place of the opening pattern CHX and 200 mJ / cm ^2, is set to 40 mJ / cm ² by using interference and diffraction of light at the location of the opening pattern KA1.

After the exposure as described above, the pattern is formed on the protective film PC by developing with an alkaline solution.

If necessary, the protective film PC may be subsequently baked.

A pixel electrode PX1 made of, for example, aluminum (Al) is formed on the surface of SUB1 of the transparent substrate on which the protective film PC is thus formed.

The pixel electrode PX1 may be made of any material having high light reflection efficiency with respect to incident light, such as molybdenum (Mo), titanium (Ti), tantalum (Ta), tungsten (W), chromium (Cr), silver. A metal such as (Ag) may be used.

Although not shown, an alignment film for initial alignment of liquid crystal molecules is formed on the surface (interface) in contact with the liquid crystal LC of the active matrix substrate.

SUB obtained by forming as described above
On the surface on 1, the irregularities CO1 regularly arranged in the period L are formed in the region RE1, and the irregularities CO2 irregularly arranged in the region RE2 are formed.

The unevenness height of the unevenness CO1 is 0.001.
It suffices if it is from 1 μm to 1 μm, and in this embodiment, it is 0.4 μm.

The concavities and convexities CO1 are regularly formed with a cycle L, and in this embodiment, they are 2 μm.

On the other hand, the average height of the irregularly arranged irregularities CO2 is 0.1 to 2 μm in the area RE of FIG.
The incident light can be scattered within this range, and is set to 0.7 μm in this embodiment.

The average distance between the vertices of the adjacent irregularities CO2 may be 10 μm to 30 μm,
In this embodiment, the thickness is 15 μm.

FIG. 14 is an enlarged view of a region E near the contact hole CH in FIG.

In the present embodiment, the contact hole CH has a quadrangular shape, and strictly has a shape with rounded corners.

The contact hole CH is not limited to the above-mentioned shape, but may be circular or elliptical.

The close contact between the pixel electrode PX1 and the protective film PC is strengthened by the anchor effect because the surface area is increased due to the presence of regular irregularities CO1 on the surface of the protective film PC.

FIG. 8 is a diagram showing the adhesion strength between the pixel electrode PX1 and the protective film PC. The density of irregularly arranged irregularities shown on the horizontal axis of the figure indicates a value obtained by dividing the number of vertices of the convex portion by the pixel area. For example, the pixel area is 16000 μ.
In the case where there are 160 vertices of irregularly arranged convex portions in m ^2, the number is 0,01 / μm ² . The density of irregularly arranged irregularities in the practical range is 0.005 pieces / μm ² to 0.015 pieces / μm in consideration of the diffusibility of incident light.
It is ² . Therefore, the structure of the present invention having the regular concavities and convexities CO1 has a pixel electrode PX in the practical range as compared with the conventional structure.
1 indicates that the adhesion strength between the protective film PC and the protective film PC is stronger.

Further, since the irregularly arranged irregularities CO2 are present, the reflection efficiency of external light is high. (Example 2) In Example 2, the adhesion strength between the pixel electrode PX1 and the protective film PC in the contact hole CH is made stronger than in Example 1.

FIG. 15 is an enlarged view of a region E near the contact hole CH in FIG.

Since the wavy shape exists in a plan view in a partial region of the contact hole CH, the pixel electrode PX
The area where 1 and the protective film PC are in contact with each other is increased, and the anchor effect strengthens the adhesion between the pixel electrode PX1 in the contact hole CH and the protective film PC.

Therefore, it is possible to prevent a decrease in reflectance due to peeling of the pixel electrode PX1.

Further, the perimeter of the contact hole in plan view increases. This increases the perimeter and reduces the probability of wire breakage in the contact hole, and the corrugation prevents the contact hole from spreading to the entire side even if peeling stress occurs on one side of the contact hole. Therefore, the rate of connection failure can be significantly reduced, and high reliability can be realized. (Example 3) In Example 3, the adhesion strength between the pixel electrode PX1 and the protective film PC in the contact hole CH is made stronger than in Example 1.

16 and 17 are enlarged views of the region E near the contact hole CH in FIG.

The presence of the wavy shape in a plan view in the region of the contact hole CH increases the contact area between the pixel electrode PX1 and the protective film PC, and the anchor effect causes the pixel electrode PX1 of the contact hole CH and the protective film PC to be in contact with each other. Will become tighter.

Therefore, the reduction of the reflectance due to the peeling of the pixel electrode PX1 is prevented.

Further, the perimeter of the contact hole in plan view increases. This increases the perimeter and reduces the probability of wire breakage in the contact hole, and the corrugation prevents the contact hole from spreading to the entire side even if peeling stress occurs on one side of the contact hole. Therefore, the rate of connection failure can be significantly reduced, and high reliability can be realized. (Embodiment 4) The embodiment 4 has a pixel electrode PX1 more than the embodiment 1.
In order to strengthen the adhesion of the protective film PC and enhance the reflection efficiency of external light, a shape in which linear irregularities are regularly arranged on the irregularly arranged irregularities is formed.

FIG. 9 is a sectional view taken along line AA of FIG.
The diagram corresponds to FIG. 3.

In order to obtain the surface shape as shown in FIG. 9, a protective film PC made of a photosensitive resin is applied after the drain electrode SD1 and the source electrode SD2 of the thin film transistor TFT are formed, and the mask of FIG. 11 described later is applied. And a step of performing exposure at an exposure dose of 200 mJ / cm ² by using FIG.
The mask is used to expose at an exposure dose of 40 mJ / cm ² , and then developed with an alkaline solution.

If necessary, the protective film PC may be subsequently fired.

In this case, the unevenness can be formed by changing the order in which the mask of FIG. 10 and the mask of FIG. 11 are used.

FIG. 10 and FIG. 11 are plan views of a mask for forming irregularities on the surface of the protective film PC used in the present invention.
12 and 11 are cross-sectional views taken along line JJ of FIG.
A sectional view taken along the line -I is shown in FIG.

The cross sectional structure of the region RE6 in FIG.
The same cross-sectional structure can be obtained as long as it is within the region surrounded by the light-shielding pattern SH3 shown in FIG. 10, and the cross-sectional view taken along the line JJ shown in FIG. Similarly, the cross-sectional structure of the region RE7 in FIG. 13 is the same as that in the region surrounded by the light shielding pattern SH6 shown in FIG. 11, and the cross-sectional view taken along the line I-I shown in FIG. It is not limited to.

In the masked region RE6 of FIG. 12, there are a linear light-shielding pattern SH4 and an opening pattern KA2. The width WX1 of the light-shielding pattern SH4 and the width DX1 of the opening pattern KA2.
Are regularly arranged in the period of XX.

Further, in this embodiment, XX is set to 2 μm.

On the other hand, in the mask of FIG. 11, the light-shielding pattern SH5 formed on the QU is the masked region RE.
In No. 7, they are arranged irregularly.

The light-shielding pattern SH5 in this case is preferably circular in plan view, but may be polygonal such as quadrangular or octagonal.

Next, S of the transparent substrate on which the protective film PC is formed
A pixel electrode PX1 made of aluminum (Al), for example, is formed on the surface of the UB1 on the protective film PC.

Although not shown, an alignment film for initial alignment of liquid crystal molecules is formed on the surface (interface) of the active matrix substrate which is in contact with the liquid crystal LC.

SUB obtained by forming as described above
In the region RE6, the surface on the top of No. 1 has a shape in which linear irregularities CO3 are regularly arranged in a cycle X on irregular irregularities CO4 drawn by a thick dotted line in the figure.

In this embodiment, the cycle X is set to 2 μm, and the height of the unevenness of the unevenness CO3 is 0.001 μm.
1 μm is sufficient, and 0.001 μm to 1 in this embodiment.
μm.

On the other hand, the average height of the irregularly arranged irregularities CO4 is 0.1 to 2 μm in the region RE of FIG.
The incident light can be scattered within this range, and is set to 0.7 μm in this embodiment.

Further, the contact hole CH has a corrugated shape in a plan view.

FIG. 18 shows the pixel electrode PX1 in this embodiment.
It is a figure which showed the adhesion strength of the protective film PC.

The close contact between the pixel electrode PX1 and the protective film PC is strengthened by the anchor effect because the surface area is increased due to the presence of regular irregularities CO3 on the surface of the protective film PC.

Similarly, in the contact hole CH having a corrugated shape with a period S in a plan view, the close contact between the pixel electrode PX1 and the protective film PC has an increased surface area and is strengthened by the anchor effect.

Further, since the irregularly arranged irregularities CO3 are present, the reflection efficiency of external light is high.

Further, the perimeter of the contact hole in plan view increases. This increases the perimeter and reduces the probability of wire breakage in the contact hole, and the corrugation prevents the contact hole from spreading to the entire side even if peeling stress occurs on one side of the contact hole. Therefore, the rate of connection failure can be significantly reduced, and high reliability can be realized.

[0112]

As is apparent from the above description, according to the present invention, it is possible to realize a liquid crystal display device having an improved adhesion strength between a pixel electrode and a protective film, a high reliability and a high reflectance. Further, by having both the regular portion and the irregular portion, it is possible to realize a liquid crystal display device having an electrode that further reflects external light without being reflected. In addition, since the contact hole portion has a corrugated shape, even if peeling stress occurs on one side of the contact hole due to stress, it can be prevented from spilling over the entire side, so that the rate of connection failure can be greatly reduced, which is high. A reliable liquid crystal display device can be realized. Further, in manufacturing, the yield can be improved.

[Brief description of drawings]

FIG. 1 is an overall equivalent circuit showing an embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a plan view showing an embodiment of a pixel of the liquid crystal display device according to the present invention.

FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2 in one embodiment.

FIG. 4 is a cross-sectional view taken along line BB of FIG. 2 in one embodiment.

5 is an explanatory view of a photomask for forming the surface shape of the pixel electrode in FIGS. 3 and 4. FIG.

6 is a cross-sectional view taken along the line CC of FIG.

7 is a cross-sectional view taken along the line DD of FIG.

FIG. 8 is a graph comparing the adhesion strength between the pixel electrode and the resin that is the base of the pixel electrode between the embodiment of the present invention and the related art.

FIG. 9 is a sectional view taken along line AA of FIG. 2 in another embodiment.

FIG. 10 is an explanatory diagram of a photomask for forming the pixel electrode surface shape of FIG. 9 in another embodiment.

FIG. 11 is an explanatory diagram of a photomask for forming the surface shape of the pixel electrode of FIG. 9 in another embodiment.

12 is a sectional view taken along line JJ of FIG.

13 is a cross-sectional view taken along the line I-I of FIG.

FIG. 14 is an enlarged plan view of a region E of FIG. 2 in one embodiment.

FIG. 15 is an enlarged plan view of a region E of FIG. 2 according to another embodiment.

16 is an enlarged plan view of a region E of FIG. 2 in another embodiment.

FIG. 17 is an enlarged plan view of a region E of FIG. 2 in another embodiment.

FIG. 18 is a graph comparing the adhesion strength between the pixel electrode and the resin that is the base of the pixel electrode with that of another example of the present invention in the related art.

[Explanation of symbols]

SUB ... Transparent substrate, GL ... Gate signal line, DL ... Drain signal line, AS ... Semiconductor layer, TFT ... Thin film transistor, PX ... Pixel electrode, GI ... Insulating film, PS ... Protective film, L
C ... liquid crystal, CH ... contact hole, QU ... transparent substrate,
KA ... Opening pattern in mask, SH ... Shading pattern in mask, SD ... Source / drain electrode, CO ... Concavo-convex shape of pixel surface.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ryutaro Oke             Hitachi, Ltd. 3300 Hayano, Mobara-shi, Chiba             Factory Display Group F-term (reference) 2H090 HA04 HA05 HA06 HB07X                       HC05 HC11 HC12 HD06 HD08                       LA01 LA04 LA20                 2H091 FA16 FD04 GA02 GA07 GA13                       LA12 LA16                 2H092 GA19 HA05 JA26 JA46 JB56                       KB25 MA10 MA14 MA18 NA18                       NA29 PA12                 5F110 AA30 BB01 CC07 GG02 GG13                       GG15 HK09 HL02 HL03 HL04                       HM20 NN02 NN03 NN24 NN27                       NN40 NN72

Claims (11)

[Claims] 1. A transparent substrate and another substrate which is arranged to face the transparent substrate with a liquid crystal layer interposed therebetween, and a plurality of scanning wirings on the other substrate and wirings in a direction intersecting with the scanning wirings. A plurality of signal lines, a thin film transistor provided in the vicinity of each intersection thereof, a protective film formed so as to cover the thin film transistor and the signal line, and a source electrode of the thin film transistor formed on the protective film. In a liquid crystal display device having an electrically connected pixel electrode and the pixel electrode formed of a material having light reflectivity, a plurality of thin linear lines are formed in a region of the protective film below the pixel electrode. A first region in which a concave portion or a convex portion is formed and a second region in which the concave portion or the convex portion is formed are arranged between the first regions, and a thin linear shape in the first region. The width of the recess or protrusion is A liquid crystal display device, wherein the liquid crystal display device is substantially regular and the width of the second region is larger than the regular width. 2. A transparent substrate and another substrate which is arranged to face the transparent substrate with a liquid crystal layer interposed therebetween, and a plurality of scanning wirings on the other substrate and wirings in a direction intersecting with the scanning wirings. A plurality of signal wirings, a thin film transistor provided near each intersection thereof, a protective film formed to cover the thin film transistor and the signal wiring, and a source electrode of the thin film transistor formed on the protective film. In a liquid crystal display device having pixel electrodes electrically connected to each other, wherein the pixel electrodes are formed of a material having light reflectivity, a plurality of thin linear lines are formed in a region of the protective film below the pixel electrodes. A first region in which a concave portion or a convex portion is formed and a second region in which a concave portion or a convex portion is formed across the first region, and a thin linear concave portion in the first region Or the width of the convex part is A liquid crystal display device, which is substantially regular and in which the second regions are irregularly arranged. 3. A transparent substrate and another substrate which is arranged to face the transparent substrate with a liquid crystal layer interposed therebetween, and a plurality of scanning wirings on the other substrate and wirings in a direction intersecting with the scanning wirings. A plurality of signal wirings, a thin film transistor provided near each intersection thereof, a protective film formed to cover the thin film transistor and the signal wiring, and a source electrode of the thin film transistor formed on the protective film. A liquid crystal display device having a pixel electrode electrically connected through a contact hole, wherein at least a part of the contact hole has a corrugated shape in a plan view. 4. A plurality of linear concave portions or convex portions arranged substantially regularly in a region of the protective film below the pixel electrode, wherein the corrugated shape has a plurality of linear concave portions or 4. A regularity substantially similar to that of the convex portion.
The liquid crystal display device according to item 1. 5. The corrugated shape is formed on or adjacent to an extension line of the plurality of linear recesses or projections which are substantially regularly arranged. The liquid crystal display device according to claim 1. 6. The liquid crystal display device according to claim 1, wherein an interval of the linear recesses or protrusions arranged in a regular manner has an error within 50%. 7. The liquid crystal display device according to claim 1, wherein an interval between the linear recesses or protrusions arranged substantially regularly is within 10%. 8. The liquid crystal display device according to claim 1, wherein the substantially regular linear recesses or protrusions have a period of 1 μm to 6 μm. 9. The liquid crystal according to claim 1, wherein the depth of the concave portions or the height of the convex portions which are substantially regularly arranged is 0.001 μm to 1 μm. Display device. 10. A step of applying a photosensitive resin so as to cover the entire surface of the substrate, and exposing the resin using a mask in which linear light-shielding patterns and linear opening patterns are arranged regularly. There is a step of exposing the resin using a mask in which dots or strips of light-shielding patterns are irregularly arranged,
A method for manufacturing a liquid crystal display device, which comprises developing the resin with an alkaline solution to form a pattern. 11. A photosensitive resin is applied, and exposure is carried out using a mask having regularly arranged linear light-shielding patterns and linear opening patterns and irregularly arranged dot-shaped or band-shaped light-shielding patterns. Then, the resin is developed with an alkaline solution to form a pattern, which is a method for manufacturing a liquid crystal display device.