JP2004062145A - In-plane switching mode active matrix type liquid crystal display and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a display defect caused by a change in characteristics of a thin film transistor and a display defect caused by a short circuit between a pixel electrode and a common electrode and to enlarge an aperture ratio, in an in-plane switching mode liquid crystal display. <P>SOLUTION: In the liquid crystal display 10, a scanning line 20 and a common electrode wiring 21 are formed in the same layer so as to be parallel to each other. A data line 24 and the scanning line 20 are covered with a common electrode 27 via an interlayer insulating film 26 and the common electrode wiring 21 is singly formed on one side of the scanning line 20. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal display device, and more particularly to a lateral electric field type active matrix liquid crystal display device and a method of manufacturing the same.
[0002]
[Prior art]
Liquid crystal display devices are of a type in which the direction of the molecular axis of the aligned liquid crystal molecules (referred to as "director") is rotated in a plane perpendicular to the substrate to perform display, and a plane parallel to the substrate. There is a type in which the image is rotated and displayed.
[0003]
A typical example of the former is a TN (Twisted Nematic) mode liquid crystal display device, and the latter is called an IPS (In-Plane Switching) mode (transverse electric field type) liquid crystal display device.
[0004]
Since the IPS mode liquid crystal display device basically looks only in the short axis direction of the liquid crystal molecules even when the viewpoint is moved, there is no dependence of the “standing” of the liquid crystal molecules on the viewing angle. A wider viewing angle than a TN mode liquid crystal display device can be achieved.
[0005]
For this reason, in recent years, IPS mode liquid crystal display devices tend to be used more frequently than TN mode liquid crystal display devices.
[0006]
Examples of the IPS mode liquid crystal display device include those described in Japanese Patent No. 3125872 (JP-A-2000-89240) and JP-A-2000-81637.
[0007]
As a typical example of the conventional IPS mode liquid crystal display device, FIGS. 40 and 41 show a liquid crystal display device described in Japanese Patent No. 3125872 (JP-A-2000-89240). FIG. 40 is a plan view of the liquid crystal display device described in the publication, and FIG. 41 is a cross-sectional view taken along line XX of FIG.
[0008]
As shown in FIGS. 40 and 41, the scanning lines 101 and the data lines 102 are covered with a common electrode 103.
[0009]
[Problems to be solved by the invention]
In the conventional liquid crystal display device shown in FIGS. 40 and 41, the common electrode wiring 105 and the common electrode 103 shield the scanning line 101 and the data line 102, respectively. 41), the liquid crystal display device shown in FIGS. 40 and 41 has the following problem.
[0010]
When the common electrode wiring 105 is formed of a transparent conductive film, the wiring resistance increases, so that the common electrode wiring 105 is delayed, and crosstalk occurs in the direction of the scanning line 101 depending on the display pattern.
[0011]
When the common electrode wiring 105 is formed of an opaque metal film, the liquid crystal comes into contact with the opaque metal via the alignment film. Therefore, when a DC voltage is applied, the opaque metal is included in the liquid crystal by an electrochemical reaction. It elutes and display stains caused by this are easily generated on the display screen.
[0012]
The present invention has been made in view of such a problem, and it is possible to dispose a low-resistance common electrode wiring under an interlayer insulating film that is stable for display, and further increase the aperture ratio. It is an object of the present invention to provide a horizontal electric field type liquid crystal display device and a method of manufacturing the same.
[0013]
[Means for Solving the Problems]
In order to achieve this object, the present invention provides a liquid crystal display device comprising an active element substrate, a counter substrate, and a liquid crystal layer held between the active element substrate and the counter substrate. Wherein the active element substrate has a gate electrode, a drain electrode, a thin film transistor having a source electrode, a pixel electrode corresponding to a pixel to be displayed, a common electrode to which a reference potential is applied, a data line, and a scan line. , A common electrode line, the gate electrode is electrically connected to the scan line, the drain electrode is connected to the data line, the source electrode is connected to the pixel electrode, and the common electrode is connected to the common electrode line. And the electric field applied between the pixel electrode and the common electrode, the electric field substantially parallel to the surface of the active element substrate causes the molecular axis of the liquid crystal layer to be in a plane parallel to the active element substrate. In a lateral electric field type active matrix type liquid crystal display device which performs display by rotating the scanning line and the common electrode wiring, the scanning line and the common electrode wiring are formed in the same layer and parallel to each other, and the data line and the scanning The line is covered by the common electrode via an interlayer insulating film, the common electrode wiring is formed only on one side of the scanning line, and the common electrode is a contact provided on the interlayer insulating film. A horizontal electrode is electrically connected to the common electrode wiring via a hole, and the common electrode is formed so as to shield a gap between the scanning line and the common electrode wiring. An electric field type active matrix liquid crystal display device is provided.
[0014]
In the in-plane switching mode active matrix liquid crystal display device according to the present invention, the scanning lines and the data lines are covered with the common electrode via the interlayer insulating film. For this reason, the common electrode shields the leakage electric field from the scanning line and the data line, and as a result, an effective display area that can be controlled by the pixel electrode and the common electrode can be enlarged. Accordingly, the area of the common electrode wiring can be reduced. Specifically, in the conventional IPS mode liquid crystal display device, common electrode wirings are provided on both sides of the scanning line in order to shield a leakage electric field from the scanning line. In the apparatus, since the common electrode has a function of shielding a leakage electric field from the scanning line, it is possible to reduce the number of common electrode wirings for shielding the leakage electric field from the scanning line to one.
[0015]
Further, in the active matrix liquid crystal display device according to the present invention, since the pixel electrode and the common electrode are formed in different layers, a short circuit between the two electrodes can be completely prevented.
[0016]
The common electrode is electrically connected to the common electrode wiring via a contact hole provided in the interlayer insulating film. Thereby, the resistance of the common electrode can be reduced, and display defects such as crosstalk due to signal delay can be reduced.
[0017]
Since the common electrode is formed to shield a gap between the scanning line and the common electrode line, a horizontal electric field generated between the scanning line and the common electrode line can be completely shielded.
[0018]
In a case where the present invention is applied to the above-described single-domain liquid crystal display device, the contact hole is provided with a rubbing direction with respect to a data line extending direction when a rubbing direction is given in a plan view of each pixel. Preferably, it is formed at any one of the vicinity of two corners giving a diagonal line obtained by rotating at an acute angle in the same direction as the direction.
[0019]
By providing a contact hole at such a position, a reverse rotation preventing structure is provided at the end of the pixel to stabilize the alignment. Therefore, the contact hole and the common electrode reverse rotation preventing structure can be efficiently arranged, and the aperture ratio can be increased.
[0020]
In the active matrix type liquid crystal display device, for example, electric fields in first and second directions substantially parallel to a surface of the active element substrate are applied between the pixel electrode and the common electrode, A first sub-pixel region rotated in a first rotation direction in a plane in which a molecular axis of the liquid crystal layer is parallel to a surface of the active element substrate, and an electric field in the second direction. Is applied, a second sub-pixel region rotated in a second rotation direction different from the first rotation direction in a plane in which a molecular axis of the liquid crystal layer is parallel to a surface of the active element substrate; It is also possible to form as what has.
[0021]
That is, the present invention can be applied not only to a so-called single-domain liquid crystal display device but also to a multi-domain liquid crystal display device.
[0022]
Further, when the present invention is applied to the above-described multi-domain liquid crystal display device, the contact hole is, in a plan view of a pixel, a direction in which the common electrode wiring extends toward the inside of the pixel, It is preferable that the common electrode is provided at any one of corner positions such that the angle between the common electrode wiring and the direction extending toward the center of the pixel is 90 degrees or more.
[0023]
By providing a contact hole at such a position, the aperture ratio can be increased.
[0024]
Preferably, the common electrode extends at least 3 μm or more from the data line in the width direction.
[0025]
Further, it is preferable that the common electrode protrudes at least 1 μm or more from the scanning line in the width direction.
[0026]
Preferably, the common electrode is formed in a layer closer to the liquid crystal layer than the pixel electrode, and the common electrode and the pixel electrode are preferably electrically insulated from each other by an interlayer insulating film.
[0027]
It is preferable that the pixel electrode and the data line are formed in the same layer.
[0028]
By forming the pixel electrode and the data line in the same layer, both can be formed in a common pattern, and an increase in the number of manufacturing steps can be prevented.
[0029]
The pixel electrode may include a plurality of first portions and a second portion that connects the plurality of first portions to each other at an end of the first portion. Preferably, the two portions are arranged on the common electrode wiring. By arranging the second portion in this way, the second portion can form a storage capacitor together with the common electrode wiring.
[0030]
It is preferable that the second portion of the pixel electrode is separated from the next scanning line by 3 μm or more.
[0031]
The common electrode may be formed in a layer closer to the liquid crystal layer than the pixel electrode. In this case, the pixel electrode and the common electrode can form a storage capacitor therebetween.
[0032]
The common electrode and the pixel electrode are preferably formed of a transparent conductive material, for example, ITO (Indium Tin Oxide).
[0033]
Thereby, the aperture ratio can be improved.
[0034]
As the interlayer insulating film, any one of a film made of an organic material, a film made of a transparent inorganic material, and a film having a two-layer structure of a film made of an organic material and a film made of a transparent inorganic material is selected. Is possible.
[0035]
The interlayer insulating film is formed by laminating an organic film and an inorganic film, and the interlayer insulating film made of the organic film is provided on the scanning line, the data line, and the common electrode line, and the scanning line and the data line. And it is preferably formed near the common electrode wiring.
[0036]
Alternatively, the interlayer insulating film is formed by laminating an organic film and an inorganic film, and the interlayer insulating film made of the organic film is formed on the scanning line and the data line and in the vicinity of the scanning line and the data line. It is preferred that
[0037]
Alternatively, the interlayer insulating film is formed by stacking an organic film and an inorganic film, and the interlayer insulating film made of the organic film is formed on the data line and the thin film transistor and in the vicinity of the data line and the thin film transistor. Is preferred.
[0038]
Alternatively, it is preferable that the interlayer insulating film is formed by laminating an organic film and an inorganic film, and the interlayer insulating film made of the organic film is formed on the data line and in the vicinity of the data line.
[0039]
Further, it is preferable that the interlayer insulating film made of the organic film is formed only inside the pattern of the common electrode.
[0040]
This makes it possible to reduce the capacitance between wirings without lowering the strength of the horizontal electric field due to the organic film, thereby improving display quality.
[0041]
The interlayer insulating film made of the organic film may be formed of a photosensitive resin material.
[0042]
Preferably, the thin film transistor is formed at an intersection of the scanning line and the data line, and the drain electrode of the thin film transistor is formed directly by the data line.
[0043]
This eliminates the necessity of forming the drain extraction electrode formed in the conventional IPS mode liquid crystal display device, and can minimize the area occupied by the thin film transistor in the pixel. In addition, the aperture ratio can be improved by an amount corresponding to the area of the drain extraction electrode that is no longer needed.
[0044]
The black matrix layer can be formed, for example, in a matrix. Preferably, the black matrix layer covers the thin film transistor and is formed as an isolated pattern only on the thin film transistor.
[0045]
By forming the black matrix layer in the minimum area as described above, the aperture ratio can be further improved.
[0046]
The black matrix layer is 1 × 10 ¹⁰ It is preferable to form from a material having a specific resistance of Ω · cm or more.
[0047]
It is preferable that the color layer constituting the color filter has an edge parallel to the data line.
[0048]
As described above, by forming the edge of the color layer in parallel with the data line, it is possible to prevent an unnecessary light-shielding region from increasing, and to further improve the aperture ratio.
[0049]
Further, it is preferable that each color layer constituting the color filter is formed with no gap between the adjacent color layers or overlaps with the adjacent color layers.
[0050]
If there is a gap between adjacent color layers, when a single color is displayed, a predetermined color is mixed with white, which causes a problem that the range of displayable colors (chromaticity range) is narrowed. Furthermore, when observing the liquid crystal panel obliquely, light passing through the pixel is observed so as to escape from an adjacent pixel, so that the display color may be shifted in an oblique visual field. Therefore, these problems can be prevented by forming each color layer with no gap between adjacent color layers or overlapping each other with adjacent color layers.
[0051]
A columnar pattern for securing a gap between the active element substrate and the counter substrate may be provided so as to be arranged at an arbitrary position between the scanning line and the common electrode wiring.
[0052]
Since it is easier to make the height of the columnar pattern uniform than to make the spacer diameter uniform, the use of the columnar pattern makes the gap between the active element substrate and the counter substrate uniform. It becomes easier.
[0053]
This columnar pattern may be formed on either the active element substrate or the counter substrate.
[0054]
The liquid crystal material constituting the liquid crystal layer preferably has Δε of 9 or more.
[0055]
More preferably, the liquid crystal material constituting the liquid crystal layer has Δε of 11 or more.
[0056]
The liquid crystal material forming the liquid crystal layer preferably has an N / I point of 80 degrees Celsius or more.
[0057]
It is preferable that an opening is formed in the common electrode on a channel of the thin film transistor, and an end of the opening is separated from an end of the channel by a predetermined distance.
[0058]
By providing such an opening, the thin film transistor is not covered with the common electrode, so that a change in the potential of the common electrode affects the thin film transistor, which prevents the characteristics of the thin film transistor from shifting. Can be. In particular, when the liquid crystal display device is driven by the gate line inversion, since the potential of the common electrode greatly fluctuates, it is effective to form the above-described opening in the common electrode.
[0059]
The present liquid crystal display device may further include a reverse rotation prevention structure for preventing the liquid crystal from rotating in the opposite direction in the sub-pixel region where the liquid crystal molecules rotate in the same direction. In this reverse rotation prevention structure, the relationship between the rubbing axis and the direction of the electric field generated in the sub-pixel region is such that, in all the regions in the sub-pixel region, the direction of the electric field is changed by the acute angle rotation from the rubbing axis in the same direction. And an auxiliary electrode provided with an equal potential to at least one of the pixel electrode and the common electrode.
[0060]
By preventing the liquid crystal from rotating in the reverse direction using this reverse rotation prevention structure, that is, by fixing the twist direction of the liquid crystal in one direction, the reliability of display can be improved.
[0061]
The data line is electrically connected to a protection circuit wiring formed in the same layer as the scanning line through a contact hole formed in an insulating film in a peripheral portion of the screen, and the scanning line is connected to the screen. In the peripheral portion, it is preferable that the peripheral portion is electrically connected to a protection circuit wiring formed in the same layer as the data line through a contact hole formed in the insulating film.
[0062]
The data line is electrically connected to a protection circuit wiring formed in the same layer as the scanning line by a conductive pattern formed in an upper layer through a contact hole formed in the interlayer insulating film in a peripheral portion of a screen. The scanning line is connected to the data line and the protection line is formed in the same layer as the data line by a conductive pattern formed in an upper layer through a contact hole formed in the interlayer insulating film in a peripheral portion of the screen. Preferably, it is electrically connected to the circuit wiring.
[0063]
The above-described in-plane switching mode active matrix type liquid crystal display device according to the present invention can be mounted on an electronic device and used.
[0064]
By manufacturing a liquid crystal panel using the active matrix liquid crystal display device according to the present invention, an aperture ratio in a display portion can be improved and luminance of the display portion can be improved.
[0065]
Further, the present invention is a liquid crystal display device comprising an active element substrate, a counter substrate, and a liquid crystal layer held between the active element substrate and the counter substrate, The active element substrate includes a thin film transistor having a gate electrode, a drain electrode, and a source electrode, a pixel electrode corresponding to a pixel to be displayed, a common electrode to which a reference potential is applied, a data line, a scanning line, and a common electrode wiring. Wherein the gate electrode is electrically connected to the scanning line, the drain electrode is connected to the data line, the source electrode is connected to the pixel electrode, and the common electrode is connected to the common electrode wiring, respectively. The molecular axis of the liquid crystal layer is rotated in a plane parallel to the active element substrate by an electric field applied between the pixel electrode and the common electrode and substantially parallel to the surface of the active element substrate. In the method of manufacturing an in-plane switching type active matrix liquid crystal display device for performing display according to the above, the scanning lines and the common electrode wiring are arranged on the same layer in parallel with each other, and the common electrode wiring is arranged on one side of the scanning line. A step of forming only one, a step of forming an interlayer insulating film on the data line and the scanning line, a step of forming a contact hole in the interlayer insulating film, and a step of forming a contact hole on the interlayer insulating film through the contact hole. Forming the common electrode so as to be electrically connected to the common electrode wiring and to shield a gap between the scanning line and the common electrode wiring. Provided is a method for manufacturing a lateral electric field type active matrix liquid crystal display device.
[0066]
Further, the present manufacturing method preferably includes a step of forming the pixel electrode and the data line in the same layer.
[0067]
The method may further include forming the pixel electrode from a plurality of first portions and a second portion interconnecting the plurality of first portions at an end of the first portion. Preferably, it is provided. In this case, the second portion is located on the common electrode line and forms a storage capacitor with the common electrode line.
[0068]
The interlayer insulating film is selected from any of a film made of an organic material, a film made of a transparent inorganic material, and a film having a two-layer structure of a film made of an organic material and a film made of a transparent inorganic material. Is preferred.
[0069]
Further, in the present manufacturing method, the interlayer insulating film is formed from a stack of an organic material and an inorganic material, and the interlayer insulating film made of the organic material is formed on the scanning lines, the data lines and the common electrode wiring, and It is preferable that the method further includes a step of forming the scanning line, the data line, and the common electrode wiring in the vicinity.
[0070]
Alternatively, in the manufacturing method, the interlayer insulating film is formed from a stack of an organic material and an inorganic material, and the interlayer insulating film made of the organic material is formed on the scanning line and the data line, and the scanning line and the data line. It is preferable to include a step of forming the film in the vicinity of.
[0071]
Alternatively, in the present manufacturing method, the interlayer insulating film is formed from a stack of an organic material and an inorganic material, and the interlayer insulating film made of the organic material is formed on the data line and the thin film transistor, and the data line and the thin film transistor. It is preferable to include a process of forming the vicinity.
[0072]
Alternatively, the present manufacturing method includes a step of forming the interlayer insulating film from a stack of an organic material and an inorganic material, and forming the interlayer insulating film made of the organic material on the data line and in the vicinity of the data line. Is preferred.
[0073]
Further, it is preferable that the present manufacturing method includes a step of forming the black matrix layer as an isolated pattern only on the thin film transistor so as to cover the thin film transistor.
[0074]
Further, the present manufacturing method preferably includes a step of forming a color layer constituting a color filter so as to have an edge parallel to the data line.
[0075]
In addition, the present manufacturing method preferably includes a step of forming the color layers constituting the color filter so that each color layer has no gap between adjacent color layers or overlaps with the adjacent color layers. .
[0076]
Further, in the present manufacturing method, between the scanning line and the common electrode wiring, a columnar pattern for securing a gap between the active element substrate and the counter substrate is formed on the active element substrate or the counter substrate. It is preferable to include a process of forming the first substrate.
[0077]
Further, the present manufacturing method preferably includes a step of forming an opening in the common electrode on a channel of the thin film transistor. In this case, the end of the opening is formed to be separated from the end of the channel by a predetermined distance.
[0078]
Further, in the present manufacturing method, the data line is electrically connected to a protection circuit wiring formed in the same layer as the scanning line through a contact hole formed in an insulating film in a peripheral portion of a screen, and the scanning is performed. It is preferable that the method further includes a step of electrically connecting the line to a protection circuit wiring formed in the same layer as the data line through a contact hole formed in the insulating film in a peripheral portion of the screen.
[0079]
Further, in the present manufacturing method, the data line is protected in a peripheral portion of a screen by a conductive pattern formed in an upper layer through a contact hole formed in the interlayer insulating film and formed in the same layer as the scanning line. The scanning line is electrically connected to circuit wiring, and the scanning line is formed in the same layer as the data line by a conductive pattern formed through a contact hole formed in the interlayer insulating film in a peripheral portion of a screen. It is preferable to include a step of electrically connecting to the circuit wiring.
[0080]
BEST MODE FOR CARRYING OUT THE INVENTION
(First embodiment of the present invention)
1, 2, and 3 show an in-plane switching mode active matrix liquid crystal display device according to a first embodiment of the present invention. FIG. 1 is a plan view of an active matrix type liquid crystal display device 10 according to the present embodiment, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is a view of the active matrix type liquid crystal display device 10 shown in FIG. It is a circuit diagram of a unit pixel portion.
[0081]
As shown in FIG. 2, the liquid crystal display device 10 includes an active element substrate 11, an opposing substrate 12, and a liquid crystal layer 13 held between the active element substrate 11 and the opposing substrate 12. Become.
[0082]
The opposing substrate 12 includes a transparent insulating substrate 16, a black matrix layer 17 formed in a matrix as a light shielding film on the transparent insulating substrate 16, and a black matrix layer 17 on the transparent insulating substrate 16 partially. The color layer 18 is formed so as to overlap, and a transparent overcoat layer 19 formed so as to cover the black matrix layer 17 and the color layer 18.
[0083]
Further, in order to prevent charging due to contact from the surface of the liquid crystal display panel from affecting the liquid crystal layer 13 electrically, a transparent conductive layer (not shown) is provided on the back surface of the transparent insulating substrate 16. ) Is formed.
[0084]
The color layer 18 is formed of a resin film containing red (R), green (G), and blue (B) dyes or pigments.
[0085]
The active element substrate 11 includes: a transparent insulating substrate 22; a first metal layer 40a formed on the transparent insulating substrate 22 to form the gate electrode 30a (see FIG. 3) and the common electrode wiring 21; A gate insulating film 23 formed on the transparent insulating substrate 22 to cover the metal layer 40a; an island-shaped amorphous silicon film 30b formed on the gate insulating film 23; a data line 24; a source electrode 30c; A second metal layer 40b forming the electrode 25; and an interlayer insulating film 26 formed on the gate insulating film 23 to cover the second metal layer 40b, ie, the data line 24, the source electrode 30c, and the pixel electrode 25. And a common electrode 27 formed of a transparent electrode on the interlayer insulating film 26.
[0086]
The island-shaped amorphous silicon film 30b, the data line 24, and the source electrode 30b constitute a thin film transistor (TFT) 30.
[0087]
In the present specification, in the active element substrate 11 and the counter substrate 12, a layer closer to the liquid crystal layer 13 is referred to as an upper layer, and a layer farther from the liquid crystal layer 13 is referred to as a lower layer.
[0088]
The active element substrate 11 and the counter substrate 12 each have an alignment film (not shown) disposed thereon, and have an angle of about 10 to 30 degrees from the extending direction of the pixel electrode 25 and the common electrode 27 (this angle is After the rubbing treatment is performed so that the liquid crystal layer 13 is homogeneously aligned in a predetermined direction L in which the liquid crystal layer 13 is tilted (referred to as the initial orientation direction of the molecules), the liquid crystal layers 13 are bonded to face each other.
[0089]
A polarizing plate (not shown) is attached outside the active element substrate 11, and a polarizing plate (not shown) is attached outside the opposing substrate 12 via a conductive layer (not shown). . The polarizing plate on the active element substrate 11 side sets the polarization axis perpendicular to the rubbing axis, and the polarizing plate on the counter substrate 12 side sets the polarization axis parallel to the rubbing axis, and the polarizing axes of both polarizing plates are orthogonal to each other. Is set to
[0090]
A number of spacers 28 (only one is shown in FIG. 2) for maintaining the thickness of the liquid crystal layer 13 are disposed between the active element substrate 11 and the opposing substrate 12. Is formed with a seal (not shown) for preventing liquid crystal molecules from leaking outside.
[0091]
A data signal is supplied to the data line 24 formed on the active element substrate 11, a reference potential is supplied to the common electrode wiring 21 and the common electrode 27, and a scanning signal is supplied to the scanning line 20.
[0092]
As shown in FIG. 1, the thin film transistor 30 is provided at an intersection of the scanning line 20 and the data line 24 in correspondence with each pixel. That is, the thin film transistor 30 is formed so as to be directly connected to the data line 24.
[0093]
More specifically, in the conventional IPS mode liquid crystal display device shown in FIG. 40, the drain electrode is formed by extending the drain extraction electrode 154a from the data line 154. In the liquid crystal display device 10, by connecting the thin film transistor 30 directly to the data line 24, it is not necessary to form the drain extraction electrode 154a extending from the data line.
[0094]
The gate electrode 30a is electrically connected to the scanning line 20, the drain electrode is electrically connected to the data line 24, and the source electrode 30c is electrically connected to the pixel electrode 25.
[0095]
In the liquid crystal display device 10 according to the present embodiment, a protection circuit for protecting the data lines 24 and the scanning lines 20 can be provided.
[0096]
FIG. 34 is a plan view illustrating an example of the protection circuit.
[0097]
The data lines 24 are formed in the peripheral portion of the screen at a protection circuit wiring 24A formed in the same layer as the data lines 24, a contact hole 23a formed in the gate insulating film 23, and a protection circuit formed in the same layer as the scanning lines 20. The wiring 20A is connected to the protection circuit 41 via these orders.
[0098]
Similarly, the scanning line 20 is formed in the same layer as the protection circuit wiring 20B formed in the same layer as the scanning line 20, the contact hole 23c formed in the gate insulating film 23, and the data line 24 in the peripheral portion of the screen. The protection circuit wiring 24 </ b> B is connected to the protection circuit 42 through these orders.
[0099]
FIG. 35 is a plan view showing another example of the protection circuit.
[0100]
The data line 24 includes a protection circuit wiring 24A formed in the same layer as the data line 24, a contact hole 26a formed in the interlayer insulating film 26, a conductive pattern 43 formed on the interlayer insulating film 26, and The protection circuit wiring 20 </ b> A formed in the same layer as the scanning line 20 is electrically connected to the protection circuit 41 via these orders.
[0101]
Further, in the peripheral portion of the screen, the scanning line 20 includes a protection circuit wiring 20B formed in the same layer as the scanning line 20, a contact hole 26b formed in the interlayer insulating film 26, and a conductive pattern formed on the interlayer insulating film 26. The protection circuit wiring 24 </ b> B formed in the same layer as the data line 43 and the data line 24 is electrically connected to the protection circuit 42 through these orders.
[0102]
By providing the protection circuits 41 and 42, even when an abnormal potential is applied to the scanning line 20 or the data line 24, the abnormal potential of the scanning line 20 or the data line 24 escapes to the protection circuits 41 and 42. Therefore, the potential of the scanning line 20 or the data line 24 can be stabilized.
[0103]
In the active matrix type liquid crystal display device 10 according to the present embodiment, as shown in FIGS. 1 and 2, both the scanning lines 20 and the common electrode wirings 21 are formed on the transparent insulating substrate 22 in the same layer. And are formed parallel to each other.
[0104]
Further, only one common electrode wiring 21 is formed on one side of the scanning line 20.
[0105]
The common electrode 27 further covers the data line 24 and the scanning line 20 via the gate insulating film 23 and the interlayer insulating film 26, and further shields the gap between the scanning line 20 and the common electrode wiring 21. It is formed as follows.
[0106]
Although the common electrode 27 can be formed so as to cover the entire thin film transistor 30, as shown in FIG. 1, an opening 27a (a region surrounded by a broken line) exposing the channel is formed on the channel of the thin film transistor 30. It can also be formed. The end of the opening 27a is separated from the end of the channel by a predetermined distance toward the inside of the channel. That is, the opening 27a has a similar shape to the channel of the thin film transistor 30.
[0107]
Further, as shown in FIGS. 1 and 2, the opening 27 a of the common electrode 27 is formed so as to be covered by the black matrix layer 17 when viewed from above.
[0108]
Further, as shown in FIG. 1, the black matrix layer 17 (the region surrounded by the broken line in FIG. 1) is formed only above the thin film transistor 30 so as to cover the thin film transistor 30. That is, the black matrix layer 17 is formed to have a minimum size necessary to prevent light from entering the thin film transistor 30. In addition, the black matrix layer 17 is not formed on the scanning lines 20 and the data lines 24, but is formed only on the thin film transistors 30 as an isolated pattern.
[0109]
Further, a contact hole 29 is formed through the gate insulating film 23 and the interlayer insulating film 26, and the contact hole 29 is filled with a conductive material. The common electrode 27 is electrically connected to the common electrode wiring 21 via a conductive material filled in the contact hole 29.
[0110]
Each color layer 18 is formed such that its edge is parallel to the data line 24.
[0111]
Note that the edges of the color layer 18 are arranged in parallel with the data lines 24 when the data lines 24 are formed linearly as shown in FIG. 36 and when the data lines 24 are formed as shown in FIG. This includes both cases where it is formed in a bent line shape.
[0112]
In the active matrix liquid crystal display device 10 according to the present embodiment, the common electrode 27 is made of ITO (Indium Tin Oxide), which is a transparent conductive material.
[0113]
In the active matrix type liquid crystal display device 10 according to the present embodiment, a pixel selected by a scanning signal supplied via the scanning line 20 and in which a data signal supplied via the data line 24 is written. An electric field parallel to the transparent insulating substrates 16 and 22 is formed between the common electrode 27 and the pixel electrode 25. According to this electric field, the orientation direction of the liquid crystal molecules is rotated in a plane parallel to the transparent insulating substrates 16 and 22, and a predetermined display is performed.
[0114]
According to the active matrix type liquid crystal display device 10 according to the present embodiment, the following effects can be obtained.
[0115]
In the active matrix type liquid crystal display device 10 according to the present embodiment, the scanning lines 20 and the data lines 24 are covered by the common electrode 27 via the interlayer insulating film 26. Therefore, the common electrode 27 can shield the leaked electric field from the scanning line 20 and the data line 24, and can enlarge an effective display area that can be controlled by the pixel electrode 25 and the common electrode 27.
[0116]
Furthermore, since the common electrode 27 is connected to the common electrode wiring 21 through the contact hole 29, the resistance of the common electrode 27 can be reduced, and display defects such as crosstalk due to signal delay can be achieved. Can be reduced.
[0117]
Further, since the common electrode 27 can shield the leakage electric field from the scanning line 20 and the data line 24, the area of the common electrode wiring 21 can be reduced.
[0118]
Specifically, in the conventional IPS mode liquid crystal display device, it is necessary to provide the common electrode wirings 151 on both sides of the scanning line 150 in order to shield a leakage electric field from the scanning line 150. In the active matrix type liquid crystal display device 10, since the common electrode 27 has a function of shielding an electric field leaking from the scanning line 20, one common electrode wiring 21 for shielding the electric field leaking from the scanning line 20 is provided. It is possible to reduce to one. Further, by shielding between the common electrode wiring 151 and the scanning line 150, it is possible to suppress an extra electric field generated between the common electrode wiring 151 and the scanning line 150. Can be expanded effectively.
[0119]
In the active matrix type liquid crystal display device 10 according to the present embodiment, the possibility of causing a short circuit between the pixel electrode 25 and the common electrode 27 is extremely low. Therefore, the production yield of the present liquid crystal display device 10 can be kept high.
[0120]
Further, in the active matrix type liquid crystal display device 10 according to the present embodiment, the common electrode 27 is formed of ITO which is a transparent conductive material, so that the aperture ratio can be improved.
[0121]
Further, in the active matrix type liquid crystal display device 10 according to the present embodiment, the thin film transistor 30 is formed so as to be directly connected to the data line 24. For this reason, it is not necessary to form the drain extraction electrode 154a formed in the conventional IPS mode liquid crystal display device shown in FIG. 40, and the area occupied by the thin film transistor 30 in the pixel can be minimized. In addition, the aperture ratio can be improved by an amount corresponding to the area of the drain extraction electrode 154a.
[0122]
In the active matrix type liquid crystal display device 10 according to the present embodiment, as shown in FIG. 2, the black matrix layer 17 is formed only on the thin film transistor 30 so as to cover the thin film transistor 30. By forming the black matrix layer 17 in the minimum area as described above, the aperture ratio can be further improved.
[0123]
In addition, each color layer is formed with no gap between adjacent color layers or overlaps with adjacent color layers. As a result, the range of colors that can be displayed (chromaticity range) is not reduced, and the display quality is improved.
[0124]
Further, in the active matrix type liquid crystal display device 10 according to the present embodiment, each color layer 18 is formed such that an edge is parallel to the data line 24. As described above, by forming the edge of the color layer 18 in parallel with the data line 24, it is possible to prevent an unnecessary light-shielding region from increasing, and to further improve the aperture ratio.
[0125]
Further, in the active matrix type liquid crystal display device 10 according to the present embodiment, the common electrode 27 is formed so as to cover the thin film transistor 30. Thus, unnecessary leakage of the horizontal electric field from the thin film transistor 30 can be prevented. In the common electrode 27, an opening 27a for exposing the channel of the thin film transistor 30 can be formed. With such a structure, unnecessary lateral electric field leakage from the thin film transistor 30 is minimized, and a change in the potential of the common electrode 27 affects the thin film transistor 30, thereby shifting the characteristics of the thin film transistor 30. Can be prevented. In particular, when the liquid crystal display device 10 is driven by gate line inversion driving, it is effective to form the opening 27 a in the common electrode 27 because the potential of the common electrode 27 greatly varies.
[0126]
Note that, as shown in FIGS. 1 and 2, the opening 27a of the common electrode 27 is covered with the black matrix layer 17, so that the formation of the opening 27a does not affect the aperture ratio.
[0127]
Further, in the active matrix type liquid crystal display device 10 according to the present embodiment, the black matrix layer 17 is formed to have a minimum size necessary to prevent light from entering the thin film transistor 30, and is formed on the thin film transistor 30. Only as an isolated pattern. By forming the black matrix layer 17 in this manner, the aperture ratio can be increased.
[0128]
Next, specific numerical examples of the active matrix liquid crystal display device 10 according to the present embodiment will be described below.
[0129]
The common electrode 27 preferably extends at least 3 μm or more from the data line 24 in the width direction when viewed from above.
[0130]
The present inventor has experimentally determined the relationship between the amount of protrusion (μm) of the common electrode 27 from the data line 24 and the crosstalk level. FIG. 4 is a graph showing the result.
[0131]
The crosstalk level at which the viewer can visually recognize the crosstalk is 3.
[0132]
As shown in FIG. 4, when the overhang of the common electrode 27 from the data line 24 is about 2.5 μm, the crosstalk level becomes 3, and when the overhang exceeds about 2.5 μm, the crosstalk level becomes 3 or less.
[0133]
Therefore, the amount of protrusion of the common electrode 27 from the data line 24 may be about 2.5 μm or more, and if it is 3 μm or more, the crosstalk level can be reliably suppressed to the visual recognition level or less.
[0134]
The common electrode 27 preferably extends at least 1 μm or more from the scanning line 20 in the width direction when viewed from above.
[0135]
The present inventor has experimentally determined the relationship between the protruding amount (μm) of the common electrode 27 from the scanning line 20 and the crosstalk level. FIG. 5 is a graph showing the result.
[0136]
As shown in FIG. 5, when the overhang amount of the common electrode 27 from the scanning line 20 is 1.0 μm, the crosstalk level becomes the visual recognition level 3, and when the overhang amount exceeds 1.0 μm, the crosstalk level increases. The level will be 3 or less.
[0137]
Therefore, the amount of protrusion of the common electrode 27 from the scanning line 20 may be 1.0 μm or more, or if it is 1.5 μm or more, for example, the crosstalk level can be reliably suppressed to the visual level or less.
[0138]
In addition, by setting the amount of protrusion of the common electrode 27 from the scanning line 20 to 1.0 μm or more, unnecessary electric field leakage from the scanning line 20 can be suppressed. Light leakage can also be suppressed.
[0139]
Black matrix layer 17 is 1 × 10 ¹⁰ It is preferably made of a material having a specific resistance of Ω · cm or more.
[0140]
The present inventor has experimentally determined the relationship between the specific resistance (Ω · cm) of the material constituting the black matrix layer 17 and the peripheral luminance increase level. FIG. 6 is a graph showing the result.
[0141]
The level at which the viewer can visually recognize the increase in the peripheral luminance is 1.
[0142]
As shown in FIG. 6, the specific resistance of the material constituting the black matrix layer 17 is 1 × 10 ^9.5 In the case of Ω · cm, the peripheral luminance increase level becomes 1 which is the visual recognition level, and the specific resistance is 1 × 10 ^9.5 If it exceeds Ω · cm, the peripheral luminance rise level becomes 1 or less.
[0143]
Therefore, the specific resistance of the material constituting the black matrix layer 17 is 1 × 10 ^9.5 Ω · cm or more, 1 × 10 ¹⁰ If it is equal to or more than Ω · cm, the peripheral luminance increase level can be reliably suppressed to the visual recognition level or less.
[0144]
Specific resistance is 1 × 10 ^9.5 As a material having a resistance of Ω · cm or more, for example, there is a material in which a resin is dispersed in titanium oxide as a black pigment.
[0145]
Further, Δε of the liquid crystal material constituting the liquid crystal layer 13 is preferably 9 or more, and more preferably 11 or more.
[0146]
The present inventor has experimentally determined the relationship between Δε of the liquid crystal material and the VT peak voltage. FIG. 7 is a graph showing the result. The VT peak voltage indicates an applied voltage that gives the maximum transmittance.
[0147]
In order to drive the liquid crystal display device at an appropriate voltage (usually, the effective voltage between the pixel electrode and the common electrode is 5 V), it is desirable that the value of the VT peak voltage be 6 V or less, and 5.5 V or less. It is more desirable that
[0148]
As shown in FIG. 7, when Δε of the liquid crystal material is about 8.4, the VT peak voltage becomes 6 V, and when Δε of the liquid crystal material is about 10.6, the VT peak voltage becomes 5 V. 0.5V.
[0149]
Therefore, Δε of the liquid crystal material constituting the liquid crystal layer 13 may be about 8.4 or more, and if it is 9 or more, the VT peak voltage can be reliably reduced to 6 V or less. Furthermore, if Δε is 11 or more, the VT peak voltage can be reliably reduced to 5.5 V or less, and the liquid crystal display device can be driven relatively easily.
[0150]
Further, the N / I point (clearing point) of the liquid crystal material constituting the liquid crystal layer 13 is preferably at least 80 degrees Celsius, and more preferably at least 90 degrees Celsius.
[0151]
By doing so, it becomes possible to apply the present liquid crystal display device to a display device such as a mobile phone device.
[0152]
FIG. 8A is a plan view showing the positional relationship between the pixel electrode 27, the scanning line 20, and the common electrode wiring 21 when viewed from above.
[0153]
As shown in FIG. 8A, the pixel electrode 27 has a plurality of linear first portions 27b extending in parallel with each other, and extends in a direction orthogonal to the first portions 27b, and an end portion of each first portion 27b. And a second portion 27c interconnecting the plurality of first portions 27b.
[0154]
In this case, it is preferable that the second portion 27c be disposed so as to overlap the common electrode wiring 21. By overlapping the second portion 27c with the common electrode wiring 21, it becomes possible for the second portion 27c and the common electrode wiring 21 to form a storage capacitor 32 (see FIG. 3) therebetween.
[0155]
Further, when the pixel electrode 27 is formed from the first portion 27b and the second portion 27c as shown in FIG. 8A, the distance D between the second portion 27c and the next scanning line 20 (see FIG. (See (A)) is preferably 3 μm or more.
[0156]
The inventor has obtained the relationship between the distance D and the wiring capacitance of the scanning line 20 through experiments. FIG. 8B is a graph showing the result. The vertical axis of the graph shown in FIG. 8B indicates a relative value of the wiring capacitance when the wiring capacitance is set to 10 at a level where there is no problem in display.
[0157]
Here, if the wiring capacity of the scanning line 20 is 10 or less, no display problem occurs. If the wiring capacity of the scanning line 20 is 6 or less, a desired display can be performed.
[0158]
As shown in FIG. 8B, when the distance D is about 0.6 μm, the wiring capacity becomes 10, and when the distance D exceeds about 0.6 μm, the wiring capacity becomes 10 or less. Further, when the distance D is about 2.4 μm, the wiring capacity becomes 6, and when the distance D exceeds about 2.4 μm, the wiring capacity becomes 6 or less.
[0159]
Therefore, the distance D may be 0.6 μm or more, and if it is 1.0 μm or more, display problems can be reliably suppressed. Further, the distance D is particularly preferably 2.4 μm or more, and if it is 3 μm or more, a desirable display can be reliably performed.
[0160]
The pixel electrode 25 forms a storage capacitor 32 (see FIG. 3) between the second electrode 27c, which is a part of the common electrode 27, and the common electrode wiring 21.
[0161]
Further, it is preferable that each color layer 18 is arranged so that there is no gap between adjacent color layers. If there is a gap between the adjacent color layers 18, when a single color is displayed, a predetermined color is mixed with white, so that there is a problem that the range of displayable colors (chromaticity range) is narrowed. Furthermore, when observing the liquid crystal panel obliquely, light passing through the pixel is observed so as to escape from an adjacent pixel, so that the display color may be shifted in an oblique visual field.
[0162]
In order to ensure that there is no gap between the adjacent color layers 18, the adjacent color layers 18 can be arranged so as to overlap each other. In this case, the width of the region where the adjacent color layers 18 overlap is set to, for example, 3 μm or more.
[0163]
FIGS. 9, 10 and 11 are cross-sectional views of respective steps in an example of a method for manufacturing the active element substrate 11 in the in-plane switching mode active matrix liquid crystal display device 10 according to the present embodiment. 9, 10, and 11 include a peripheral section, a pixel section, and a pixel section plan view in order from the left.
[0164]
Hereinafter, a method of manufacturing the in-plane switching mode active matrix liquid crystal display device 10 according to the present embodiment will be described with reference to FIGS.
[0165]
First, as shown in FIG. 9A, a first metal layer 40a is formed on a transparent insulating substrate 22, the first metal layer 40a is patterned, and a gate electrode 30a, a scanning line 20, and a common electrode wiring are formed. 21 are formed at the same time.
[0166]
Next, as shown in FIG. 9B, a gate insulating film 23 is formed on the transparent insulating substrate 22 so as to cover the gate electrode 30a, the scanning line 20, and the common electrode wiring 21. Further, an i-layer 35a not doped with an impurity and an n-layer 35b doped with an n-type impurity are formed on the gate insulating film 23.
[0167]
Next, as shown in FIG. 9C, the i-layer 35a and the n-layer 35b are patterned to form an island 36 for the thin film transistor 30.
[0168]
Next, as shown in FIG. 10A, a second metal layer 40b made of chromium is formed on the gate insulating film 23 and the island 36, and the data line is formed by patterning the second metal layer 40b. 24 and the source electrode 30c are formed.
[0169]
By patterning the second metal layer 40b, although not shown, the pixel electrode 25 is also formed at the same time.
[0170]
Next, as shown in FIG. 10B, an interlayer insulating film 26 is formed to cover the gate insulating film 23.
[0171]
Next, as shown in FIG. 10C, a contact hole 29 reaching the common electrode wiring 21 and a contact hole 37 reaching the data line 24 are formed simultaneously.
[0172]
Next, as shown in FIG. 11, an ITO film is entirely formed so that the contact holes 29 and 37 are filled with ITO, and the common film 27 is formed by patterning the ITO film.
[0173]
Through the above steps, the active element substrate 11 in the active matrix liquid crystal display device 10 according to the present embodiment is formed.
[0174]
In the liquid crystal display device 10 according to the present embodiment, as shown in FIG. 1A, the liquid crystal alignment direction L (rubbing direction) defined by rubbing, the pixel electrode 25 and the common electrode 27 (and the The common electrode 21 is rotated clockwise from the liquid crystal alignment direction L by an acute angle so that the common electrode overlaps with the direction of the electric field applied between the equipotential common electrode lines 21). At 27, an oblique edge 27b as an auxiliary electrode is formed.
[0175]
If there is a region where the direction of the acute angle rotation from the liquid crystal alignment direction to the electric field direction is counterclockwise, this region is formed by applying an electric field between the pixel electrode 25 and the common electrode 27 to the target liquid crystal rotation direction. , A domain that rotates in the opposite direction is generated at the pixel end. If there is a domain that is rotating in the reverse direction and the disclination that occurs at the boundary between the domain that is rotating normally and the domain that is rotating in the reverse direction occurs for a long time, the display state changes accordingly, and the initial state changes. In some cases, the same state as described above cannot be obtained, and the reliability is reduced.
[0176]
By forming the oblique edge 27b as a reverse rotation preventing structure on the common electrode 27, such reverse rotation can be prevented. That is, the twist direction of the liquid crystal can be fixed in one direction.
(Second embodiment of the present invention)
FIG. 12 is a plan view of an in-plane switching mode active matrix liquid crystal display device 40 according to a second embodiment of the present invention.
[0177]
In the in-plane switching mode active matrix liquid crystal display device 10 according to the first embodiment, the common electrode 27 is formed of ITO which is a transparent conductive material. In the display device 40, not only the common electrode 27 but also the pixel electrode 25 is formed of ITO. Except that the pixel electrode 25 is formed of ITO, the active matrix liquid crystal display device 40 according to the present embodiment has the same configuration as the active matrix liquid crystal display device 10 according to the first embodiment. I have.
[0178]
By forming not only the common electrode 27 but also the pixel electrode 25 with ITO, which is a transparent conductive material, the aperture ratio can be further improved as compared with the active matrix type liquid crystal display device 10 according to the first embodiment.
[0179]
FIGS. 13, 14 and 15 are cross-sectional views of respective steps in an example of a method for manufacturing the active element substrate 11 in the in-plane switching mode active matrix liquid crystal display device 40 according to the present embodiment. 13, FIG. 14, and FIG. 15 include a peripheral section view, a pixel section view, and a pixel section plan view in order from the left, as in FIGS.
[0180]
Hereinafter, a method for manufacturing the in-plane switching mode active matrix liquid crystal display device 40 according to the present embodiment will be described with reference to FIGS.
[0181]
First, as shown in FIG. 13A, a first metal layer 40a is formed on a transparent insulating substrate 22, the first metal layer 40a is patterned, and a gate electrode 30a, a scanning line 20, and a common electrode wiring are formed. 21 are formed at the same time.
[0182]
Next, as shown in FIG. 13B, a gate insulating film 23 is formed on the transparent insulating substrate 22 so as to cover the gate electrode 30a, the scanning line 20, and the common electrode wiring 21. Further, an i-layer 35a not doped with an impurity and an n-layer 35b doped with an n-type impurity are formed on the gate insulating film 23.
[0183]
Next, as shown in FIG. 13C, the i-layer 35a and the n-layer 35b are patterned to form an island 36 for the thin film transistor 30.
[0184]
Next, as shown in FIG. 14A, a contact hole 37 is formed in the gate insulating film 23 in the peripheral portion of the screen. The contact hole 37 reaches the gate electrode 30a.
[0185]
Next, as shown in FIG. 14B, a second metal layer 40b made of chromium is formed, and the data line 24 and the source electrode 30c are formed by photolithography and etching of the second metal layer 40b. Form.
[0186]
At the same time, the data line 24 is electrically connected to the protection circuit wiring (not shown) formed on the same layer as the scanning line 20 by the second metal layer 40b made of chromium via the contact hole 37. Further, the scanning line 20 is connected to a protection circuit wiring (not shown) formed in the same layer as the data line 24 via a contact hole (not shown) formed in the gate insulating film 23 in the peripheral portion of the screen. Make electrical connection.
[0187]
In this case, the data line 24 and the scanning line 20 are connected at the peripheral portion of the scanning line 20, as shown in the sectional view of the peripheral portion in FIG. As described above, at this stage, the connection between the data line 24 and the scanning line 20 is performed when the data line 24 is formed by etching before the connection between the data line 24 and the scanning line 20. This is because there is a possibility of elution.
[0188]
Next, as shown in FIG. 14C, an ITO film is formed on the front surface, and the pixel electrode 25 is formed by patterning the ITO film.
[0189]
Next, as shown in FIG. 15A, an interlayer insulating film 26 is formed to cover the gate insulating film 23.
[0190]
Next, as shown in FIG. 15B, a contact hole 29 reaching the common electrode wiring 21 is formed.
[0191]
Next, as shown in FIG. 15C, an ITO film is entirely formed so that the contact hole 29 is filled with ITO, and the common electrode 27 is formed by patterning the ITO film.
[0192]
Through the above steps, the active element substrate 11 in the active matrix liquid crystal display device 40 according to the present embodiment is formed.
(Third embodiment of the present invention)
FIG. 16 is a sectional view of an in-plane switching mode active matrix liquid crystal display device 50 according to the third embodiment of the present invention.
[0193]
In the active matrix liquid crystal display device 50 according to the present embodiment, as in the active matrix liquid crystal display device 40 according to the second embodiment, the pixel electrode 25 is formed of ITO which is a transparent conductive material. Further, a transparent electrode 25a is formed as a protective layer covering the data line 24. Except that the transparent electrode 25a is formed, the active matrix liquid crystal display device 50 according to the present embodiment has the same configuration as the active matrix liquid crystal display device 40 according to the second embodiment.
[0194]
The transparent electrode 25a is made of ITO like the pixel electrode 25, and is formed simultaneously with the pixel electrode 25. Since the transparent electrode 25a can be formed by partially changing the formation pattern of the pixel electrode 25, the number of steps increases as compared with the active matrix liquid crystal display device 40 according to the second embodiment. do not do.
[0195]
By covering the data line 24 with the transparent electrode 25a, the data line 24 can be prevented from being dissolved by the etching performed when the pixel electrode 25 is formed.
(Fourth embodiment of the present invention)
FIG. 17 is a sectional view of an in-plane switching mode active matrix liquid crystal display device 60 according to a fourth embodiment of the present invention.
[0196]
As shown in FIG. 2, in the in-plane switching mode active matrix liquid crystal display device 10 according to the first embodiment, the black matrix layer 17 is provided as one component of the counter substrate 12. In the active matrix type liquid crystal display device 60 according to (1), the black matrix layer 17a is provided not on the opposing substrate 12, but on the active element substrate 11.
[0197]
Specifically, the black matrix layer 17a is formed only above the thin film transistor 30 so as to cover the opening 27a of the common electrode 27 and to cover the thin film transistor 30, similarly to the black matrix layer 17 in the first embodiment. Have been. That is, the black matrix layer 17a is formed to have a minimum size necessary to prevent light from entering the thin film transistor 30. In addition, the black matrix layer 17a is not formed on the scanning lines 20 and the data lines 24, but is formed as an isolated pattern only on the thin film transistor 30.
[0198]
Except that the black matrix layer 17a is provided on the active element substrate 11, the active matrix type liquid crystal display device 60 according to the present embodiment is the same as the in-plane switching type active matrix type liquid crystal display device 10 according to the first embodiment. It has the same configuration as
[0199]
As described above, even when the black matrix layer 17a is formed on the active element substrate 11, the same effects as those of the active matrix liquid crystal display device 10 according to the first embodiment can be obtained.
(Fifth Embodiment of the Present Invention)
FIG. 18 is a sectional view of an in-plane switching mode active matrix liquid crystal display device 70 according to a fifth embodiment of the present invention.
[0200]
As shown in FIG. 2, in the in-plane switching mode active matrix type liquid crystal display device 10 according to the first embodiment, the spacer 28 is provided with a spacer 28 in order to secure a gap between the active element substrate 11 and the counter substrate 12. It is sandwiched between two substrates 11 and 12.
[0201]
On the other hand, in the active matrix type liquid crystal display device 70 according to the present embodiment, the gap between the active element substrate 11 and the opposing substrate 12 is secured by using the columnar pattern 38 instead of the spacer 28. I have. Except for using a columnar pattern 38 instead of the spacer 28, the active matrix type liquid crystal display device 70 according to the present embodiment is different from the active field type active matrix type liquid crystal display device 10 according to the first embodiment. It has a similar configuration.
[0202]
The columnar pattern 38 can be formed, for example, from a photosensitive resin. In this case, the columnar pattern 38 is formed by coating a photosensitive resin film on the entire surface of the active element substrate 11 and then forming the columnar pattern 38 (a region where the columnar pattern 38 is not formed depending on the properties of the photosensitive resin). Only the photosensitive resin is exposed, and the photosensitive resin in a region where the columnar pattern 38 is not formed is removed by etching.
[0203]
Since it is easier to make the height of the columnar pattern 38 uniform than to make the diameter of the spacer 28 uniform, using the columnar pattern 38 in place of the spacer 28 reduces the manufacturing time of the liquid crystal display device. Can be shortened.
[0204]
The columnar pattern 38 is formed above the thin film transistor 30, that is, below the black matrix layer 17. Therefore, the aperture ratio does not decrease irrespective of the translucency of the columnar pattern 38.
[0205]
Further, in the present embodiment, the columnar patterns 38 are formed on the active element substrate 11, but the columnar patterns 38 may be formed on the counter substrate 12.
[0206]
When a columnar pattern 38 is used instead of the spacer 28, the interlayer insulating film 26 can be formed from a photosensitive resin material. By forming the interlayer insulating film 26 from a photosensitive resin material, the columnar pattern 38 can be formed by patterning the interlayer insulating film 26 into a predetermined pattern.
(Sixth embodiment of the present invention)
FIG. 19 is a sectional view of an in-plane switching mode active matrix liquid crystal display device 80 according to the sixth embodiment.
[0207]
In the first to fifth embodiments described above, the interlayer insulating film 26 is formed as a single-layer film made of either a film made of an organic material or a film made of a transparent inorganic material.
[0208]
On the other hand, in the in-plane switching mode active matrix liquid crystal display device 80 according to the present embodiment, the interlayer insulating film 26 is formed of a laminated film instead of the single-layer film. ing.
[0209]
Specifically, as shown in FIG. 19, the interlayer insulating film 26 includes a first film 26a made of an inorganic film, and a second film 26b formed so as to cover the first film 26a and made of an organic film. Has a laminated film structure.
[0210]
The second film 26b made of an organic film is formed, for example, of a photosensitive acrylic resin.
[0211]
Since the dielectric constant of the organic film is lower than the dielectric constant of the inorganic film, as compared with the case where the interlayer insulating film 26 is composed of a single inorganic film, by adopting such a laminated film structure, the dielectric constant of the entire interlayer insulating film is reduced. Rate can be reduced.
[0212]
Further, when the interlayer insulating film 26 is composed of an organic film alone, the interface state between the semiconductor layer of the thin film transistor 30 and the organic film covering the semiconductor film becomes unstable, and the leakage current of the thin film transistor 30 increases when driven at a high temperature. This may cause display unevenness. For this reason, an inorganic film such as a silicon nitride film is used as the first film 26a in contact with the semiconductor layer of the thin film transistor 30, and an organic film is stacked thereon, whereby a stable film is formed between the inorganic film and the semiconductor layer. An interface is formed, and the above-described problems can be suppressed.
(Seventh embodiment of the present invention)
FIG. 20 is a sectional view of an in-plane switching mode active matrix liquid crystal display device 90 according to the seventh embodiment.
[0213]
For example, in the in-plane switching mode active matrix liquid crystal display device 10 according to the first embodiment, the interlayer insulating film 26 is formed over the entire surface of the unit pixel region, but in the present embodiment, the interlayer insulating film 26 is formed. Is configured as a film in which an organic material and an inorganic material are laminated. Among them, the interlayer insulating film 26b made of an organic material covers the scanning line 20, the data line 24, the common electrode wiring 21, and the thin film transistor 30, and covers the scanning line 20 so as not to cover the portion related to the display of the pixel electrode 25. It is formed on the data line 24, the common electrode line 21 and the thin film transistor 30, and near the scanning line 20, the data line 24, the common electrode line 21 and the thin film transistor 30.
[0214]
The common electrode 27 covering the scanning line 21, the data line 24 and the common electrode wiring 21 is formed on an interlayer insulating film 26b made of an organic material.
[0215]
The dielectric constant of the interlayer insulating film 26b made of an organic material is, for example, about 3 to 4 when a photosensitive acrylic resin is used. When silicon nitride is used as the inorganic material, for example, the dielectric constant is about 6 to 7, so that the capacitance between the data line 24 and the common electrode 27 can be reduced to an equivalent level with about half the thickness. In the case of forming a thick film using only an inorganic material, a high load is applied to an expensive film forming apparatus to obtain good film quality, and the manufacturing cost is increased. On the other hand, the interlayer film made of an organic material can be realized at low cost because it is formed by applying a material.
[0216]
Further, as shown in FIG. 20, the interlayer film between the pixel electrode 25 and the common electrode 27 is only an inorganic film, which can be reduced in thickness. Thus, the electric field between the two electrodes can be effectively applied to the liquid crystal, so that the driving voltage can be reduced.
[0219]
For example, it is preferable that the thickness of the interlayer insulating film 26b made of an organic material be 5000 to 10,000.
[0218]
As an example, the thickness of the interlayer insulating film 26a made of an inorganic material can be 3000 °, and the thickness of the interlayer insulating film 26b made of an organic material can be 6000 °.
[0219]
If the thickness of the interlayer insulating film 26a made of an inorganic material is too thin, dielectric breakdown may occur between the pixel electrode 25 and the common electrode 27. Therefore, the interlayer insulating film 26a made of an inorganic material may have a thickness of 2000A or more. desirable.
[0220]
If the thickness of the interlayer insulating film 26b made of an organic material is too large, foreign matter adheres to a step portion of the interlayer insulating film 26b made of an organic material in a rubbing step, and the display quality deteriorates.
[0221]
If the thickness of the interlayer insulating film 26b made of an organic film is too small, the parasitic capacitance between the common electrode 27 and the data line 24 increases, and the display quality deteriorates.
[0222]
According to the present embodiment, since a region related to display between the pixel electrode 25 and the common electrode 27 is not covered with the organic film having a low dielectric constant, the horizontal electric field applied to the liquid crystal is efficiently reduced based on the potential difference between the two. It can be generated well, and an increase in parasitic capacitance between the common electrode 27 and the data line 24 can be prevented.
(Eighth embodiment of the present invention)
FIG. 21 is a plan view of an in-plane switching mode active matrix liquid crystal display device 91 according to the eighth embodiment of the present invention. The in-plane switching mode active matrix liquid crystal display device 91 according to the present embodiment corresponds to a modification of the liquid crystal display device 90 according to the seventh embodiment shown in FIG. FIG. 22 is a sectional view taken along the line aa ′ of FIG. FIG. 23 is another sectional view of the liquid crystal display device 91.
[0223]
In this embodiment, the interlayer insulating film 26 is formed as a film in which an organic material and an inorganic material are laminated, and the film made of the organic material includes the scanning line 20, the data line 24, the common electrode wiring 21, and the thin film transistor. The scanning line 20, the data line 24 and the common electrode line 21 and the thin film transistor 30, and the scanning line 20, the data line 24 and the common electrode line 21 are covered so as to cover the pixel electrode 25 and the display portion of the pixel electrode 25. And near the thin film transistor 30.
[0224]
In the present embodiment, the common electrode 27 is formed so as to cover the interlayer insulating film 26b made of an organic material.
[0225]
That is, in the present embodiment, the interlayer insulating film 26b made of an organic material is formed inside the common electrode 27 that covers the scanning line 20, the data line 24, and the common electrode wiring 21.
[0226]
Also in the present embodiment, since a region related to display between the pixel electrode 25 and the common electrode 27 is not covered with the low dielectric constant organic film, a horizontal electric field applied to the liquid crystal can be efficiently generated from a potential difference between the two. It can be generated, and an increase in parasitic capacitance between the common electrode 27 and the data line 24 can be prevented.
(Ninth embodiment of the present invention)
FIG. 24 is a plan view of an in-plane switching mode active matrix liquid crystal display device 92 according to a ninth embodiment of the present invention. The in-plane switching mode active matrix liquid crystal display device 92 according to the present embodiment corresponds to a modification of the liquid crystal display device 91 according to the eighth embodiment shown in FIG. FIG. 25 is a sectional view taken along the line bb 'of FIG.
[0227]
In this embodiment, the interlayer insulating film 26 is configured as a film in which an organic material and an inorganic material are laminated, and the film made of the organic material covers the scanning line 20 and the data line 24 and the thin film transistor 30, and The electrodes 25 are formed on the scanning lines 20 and the data lines 24 and the thin film transistors 30, and in the vicinity of the scanning lines 20 and the data lines 24 and the thin film transistors 30 so as not to cover a portion related to display of the electrodes 25.
[0228]
According to the present embodiment, since the distance between the pixel electrode 25 and the common electrode 27 can be reduced, the storage capacitance 32 (see FIG. 3) formed between the pixel electrode 25 and the common electrode 27 can be reduced. The capacity can be increased. As a result, display quality can be improved.
[0229]
Hereinafter, a method for manufacturing the active element substrate 11 in the active matrix liquid crystal display device 92 according to the ninth embodiment will be described.
[0230]
An interlayer insulating film 26b made of an organic material according to the present embodiment, whose structure is shown in FIGS. 21 to 23, is added to the manufacturing method of the first embodiment described with reference to FIGS.
[0231]
Specifically, as shown in FIG. 10A, after D-Cr patterning, the n-layer 35b on the channel is removed by etching, and then an interlayer insulating film 26a made of an inorganic material is formed.
[0232]
Further, a photosensitive acrylic resin is applied, and is exposed and developed to form an interlayer insulating film 26b made of an organic material.
[0233]
Here, the interlayer insulating film 26b made of an organic material is formed on the scanning line 20, the data line 24 and the thin film transistor 30, and near the scanning line 20, the data line 24 and the thin film transistor 30.
[0234]
Next, a contact hole 29 is formed in the interlayer insulating film 26a and the gate insulating film 23 made of an inorganic material.
[0235]
Further, an ITO film is formed thereon, and the common electrode 27 is formed by patterning the ITO film.
[0236]
The common electrode 27 is connected to the common electrode wiring 21 via the contact hole 29.
[0237]
Through the above steps, the active element substrate 11 in the active matrix liquid crystal display device 92 according to the ninth embodiment is formed.
[0238]
In the above manufacturing process, it is preferable to remove impurities adsorbed on the surface of the common electrode wiring 21 by performing, for example, oxygen plasma treatment after forming the contact hole 29.
[0239]
Thereby, the contact resistance in the contact hole 29 is reduced, and the display quality is improved.
[0240]
Further, in the above manufacturing process, after forming the interlayer insulating film 26b made of an organic material and before forming the contact hole 29, the surface of the interlayer insulating film 26b made of an organic material is modified using helium or argon plasma. It is preferable to keep it.
[0241]
Thereby, the adhesion between the interlayer insulating film 26b made of an organic material and the common electrode 27 and the patterning accuracy of the common electrode 27 are improved, and the occurrence of defects can be reduced.
[0242]
Although it is possible to perform treatment using helium or argon plasma after forming the contact hole, impurities are re-adhered to the surface of the common electrode wiring 21 and the contact resistance in the contact hole 29 is increased. Not preferred.
(Tenth embodiment of the present invention)
FIG. 26 is a plan view of an in-plane switching mode active matrix liquid crystal display device 93 according to the tenth embodiment of the present invention. The in-plane switching mode active matrix liquid crystal display device 93 according to the present embodiment corresponds to a modification of the liquid crystal display device 92 according to the ninth embodiment shown in FIG. FIG. 27 is a cross-sectional view taken along the line cc 'of FIG.
[0243]
In this embodiment, the interlayer insulating film 26 is configured as a film in which an organic material and an inorganic material are stacked, and the film made of the organic material covers the data line 24 and the thin film transistor 30 and is used for displaying the pixel electrode 25. It is formed on the data line 24 and the thin film transistor 30 and in the vicinity of the data line 24 and the thin film transistor 30 so as not to cover such a portion.
[0244]
According to the present embodiment, since the interlayer insulating film 26b made of an organic material is not formed on the scanning line 20, a step at an angle almost perpendicular to the rubbing axis L (see FIG. 1) can be reduced. This makes it possible to reduce the phenomenon of foreign matter adhering to the stepped portion that occurs in the rubbing step, and improves display quality.
(Eleventh embodiment of the present invention)
FIG. 28 is a plan view of an in-plane switching mode active matrix liquid crystal display device 94 according to an eleventh embodiment of the present invention. The in-plane switching mode active matrix liquid crystal display device 94 according to the present embodiment corresponds to a modification of the liquid crystal display device 93 according to the tenth embodiment shown in FIG. FIG. 29 is a sectional view taken along line dd ′ of FIG.
[0245]
In this embodiment, the interlayer insulating film 26 is configured as a film in which an organic material and an inorganic material are stacked, and the film made of the organic material covers the data line 24 and serves as a display portion of the pixel electrode 25. It is formed on the data line 24 and in the vicinity of the data line 24 so as not to be covered.
[0246]
According to the present embodiment, since the interlayer insulating film 26b made of an organic material is not formed on the scanning lines 20 and the thin film transistors 30, a step having an angle almost perpendicular to the rubbing axis L (see FIG. 1) can be eliminated. This makes it possible to further reduce the phenomenon of foreign matter adhering to the stepped portion generated in the rubbing step, and the display quality is improved.
[0247]
In the liquid crystal display devices 90 to 94 according to the seventh to eleventh embodiments, when the interlayer insulating film 26b is formed from an organic film, the material of the organic film can be either transparent or non-transparent. In particular, when a black organic material is used as the material of the interlayer insulating film 26b, the interlayer insulating film 26b performs the function of the black matrix layer 17, so that it is not necessary to form the black matrix layer 17. .
[0248]
Further, as a material of the interlayer film 26b, a novolak resin can be used. In this case, since the material is inexpensive, and the handling is easy, the photolithography process and the apparatus can be used commonly in the production of a thin film transistor (TFT), and thus the above structure can be realized at low cost. The advantage is obtained.
(Twelfth embodiment of the present invention)
Each of the in-plane switching mode active matrix liquid crystal display devices 10, 40, 50, 60, 70, 80, 90, 91, 92, 93 and 94 according to the first to eleventh embodiments is a so-called single domain type. Liquid crystal display device.
[0249]
The single-domain liquid crystal display device is configured such that an electric field substantially parallel to the surface of the active element substrate 11 is applied between the pixel electrode 25 and the common electrode 27 so that the molecular axis of the liquid crystal layer 13 is applied to the active element substrate 11. A liquid crystal display device of a type in which display is performed by rotating in a parallel plane.
[0250]
Each of the first to eleventh embodiments can be applied to a so-called multi-domain type liquid crystal display device.
[0251]
The multi-domain type liquid crystal display device is configured such that an electric field in two directions substantially parallel to the surface of the active element substrate 11 (herein, electric fields in the first and second directions) is applied between the pixel electrode 25 and the common electrode 27. In the first sub-pixel region to which an electric field is applied in the first direction, the molecular axis 13 of the liquid crystal layer is set in the first rotation direction in a plane parallel to the surface of the active element substrate 11. In the second sub-pixel region to which the electric field in the second direction is applied, the molecular axis of the liquid crystal layer 13 is set in the direction parallel to the surface of the active element substrate 11 in the first rotation direction. The liquid crystal display device is of a type in which the liquid crystal display device is rotated in a second rotation direction different from the above.
[0252]
That is, the first to eleventh embodiments described above are applicable not only to a single-domain liquid crystal display device but also to a multi-domain liquid crystal display device.
[0253]
When the liquid crystal display device according to the first to eleventh embodiments is configured as a single domain type liquid crystal display device, a rubbing direction L is given as shown in FIG. 30A which is a plan view of a pixel. In this case, it is preferable that the contact hole 29 is formed in one of the vicinity of two corners giving a diagonal obtained by rotating the data line 24 in the same direction as the rubbing direction L by an acute angle with respect to the extension direction of the data line 24. .
[0254]
By providing the contact hole 29 at such a position, a reverse rotation preventing structure is provided at the end of the pixel to form a reverse rotation preventing electrode of the common electrode 27 at the position of the contact hole 29 when stabilizing the alignment. Therefore, the contact hole 29 and the structure for preventing reverse rotation of the common electrode 27 can be efficiently arranged, and the aperture ratio can be increased.
[0255]
On the other hand, as shown in FIG. 30B, contact points are formed near two corners that give diagonal lines obtained by rotating the data line 24 in the direction opposite to the rubbing direction L with respect to the extending direction of the data line 24. When the hole 29 is formed, it is necessary to form the edge electrode on the outer side due to the angle of the electrode of the reverse rotation preventing structure, which causes a loss in aperture ratio.
[0256]
In the case where the liquid crystal display device according to the first to eleventh embodiments is configured as a multi-domain liquid crystal display device, as shown in FIG. At the corner where the angle between the direction extending toward the inside of the pixel and the direction extending from the common electrode wiring 151 toward the center of the pixel from the common electrode wiring 151 is 90 degrees or more. Preferably, a contact hole 29 is formed.
[0257]
In this manner, by connecting the common electrode 27 to the common electrode wiring 21 via the contact hole 29 for each unit pixel, the resistance of the entire wiring of the common electrode 27 can be reduced.
(Thirteenth embodiment of the present invention)
FIG. 32 is a sectional view of an in-plane switching mode active matrix liquid crystal display device 100 according to a thirteenth embodiment of the present invention.
[0258]
As shown in FIG. 32, in the in-plane switching mode active matrix liquid crystal display device 100 according to the thirteenth embodiment, the contact hole 29 is formed by patterning the gate insulating film 23 and the interlayer insulating film 26 collectively. The common electrode wiring 21 and the common electrode 27 are directly connected.
[0259]
According to the present embodiment, the contact hole 29 can have a large opening portion because the gate insulating film 23 and the interlayer insulating film 26 are collectively patterned.
(14th embodiment of the present invention)
FIG. 33 is a sectional view of an in-plane switching mode active matrix liquid crystal display device 110 according to a fourteenth embodiment of the present invention.
[0260]
As shown in FIG. 33, in the in-plane switching mode active matrix liquid crystal display device 110 according to the fourteenth embodiment, the contact hole 29 is formed in the contact hole 29 a formed in the gate insulating film 23 and the interlayer insulating film 26. The common electrode wiring 21 and the common electrode 27 are connected via an electrode 29c formed between the gate insulating film 23 and the interlayer insulating film 26.
[0261]
According to the present embodiment, by connecting the common electrode wiring 21 and the common electrode 27 via the electrode 29c, the contact hole 29a formed in the gate insulating film 23 and the contact hole formed in the interlayer insulating film 26 are formed. 29b, the etching depth at the time of patterning becomes shallow, and it is possible to reduce the resistance value when the common electrode wiring 21, the electrode 29c and the common electrode 27 come into contact with each other.
(Fifteenth Embodiment of the Present Invention)
In the first to twelfth embodiments, the black matrix layer 17 is formed as an isolated pattern only on the thin film transistor 30 so as to cover the thin film transistor 30.
[0262]
The black matrix layer 17 is not limited to the above-described embodiment, and may be formed to have the following embodiment.
[0263]
For example, the black matrix layer 17 covers the thin film transistor 30 and extends in the direction in which the data line 24 extends and the direction in which the scanning line 20 extends, and can be formed in a matrix.
[0264]
By forming the black matrix layer 17 in a matrix, light reflection from the data lines 24, the scanning lines 20, and the common electrode wiring 21 can be prevented, and the image quality can be improved.
[0265]
Further, for example, the black matrix layer 17 can be formed so as to cover the thin film transistor 30 and cover a gap between the scanning line 20 and the common electrode wiring 21.
[0266]
By covering the gap between the scanning line 20 and the common electrode line 21, the disorder of the alignment of the liquid crystal layer 13 generated between the scanning line 20 and the common electrode line 21 can be hidden, and the image quality can be improved.
[0267]
Further, for example, the black matrix layer 17 can be formed such that a step (edge portion) around the black matrix layer 17 is located inside the scanning line 20 when viewed from above.
[0268]
Since the step of the black matrix layer 17 causes display unevenness, the uneven display portion can be hidden by positioning the step of the black matrix layer 17 inside the scanning line 20, thereby improving the image quality. it can.
[0269]
Forming the black matrix layer 17 so that the step of the black matrix layer 17 is located inside the scanning line 20 means that the size of the black matrix layer 17 is minimized.
[0270]
In the present specification, the above-described black matrix layer 17 is described as one embodiment of the present invention. However, the above-described black matrix layer 17 is used only for the in-plane switching mode active matrix liquid crystal display device according to the present invention. However, the present invention can be applied to a general in-plane switching type active matrix liquid crystal display device.
[0271]
For example, the present invention can be applied to the liquid crystal display devices described in Japanese Patent No. 3125872 (Japanese Patent Application Laid-Open No. 2000-89240) and Japanese Patent Application Laid-Open No. 2000-81637, which are cited as the prior art in this specification. .
[0272]
In the first to fourteenth embodiments, the common electrode 27 is formed with the opening 27a for exposing the channel of the thin film transistor 30. By forming such an opening 27a, even if the potential of the common electrode 27 changes due to polarity reversal, the influence on the thin film transistor 30 can be avoided.
[0273]
In the present specification, the above-described common electrode 27 is described as one embodiment of the present invention. However, the above-described common electrode 27 is not limited to the in-plane switching mode active matrix liquid crystal display device according to the present invention. It is also applicable to a general in-plane switching type active matrix liquid crystal display device.
[0274]
For example, the liquid crystal display device described in Japanese Patent No. 3125872 (Japanese Patent Application Laid-Open No. 2000-89240) and Japanese Patent Application Laid-Open No. 2000-81637, which is cited as a conventional technology in the present specification, or the conventional IPS shown in FIG. The present invention can also be applied to a mode liquid crystal display device.
[0275]
When the common electrode 27 is applied to a general in-plane switching type active matrix liquid crystal display device, the common electrode 27 may be made of either a transparent material or an opaque material.
(Sixteenth embodiment of the present invention)
The liquid crystal display device 10 according to the first embodiment, the liquid crystal display device 40 according to the second embodiment, the liquid crystal display device 50 according to the third embodiment, the liquid crystal display device 60 according to the fourth embodiment, The liquid crystal display device 70 according to the fifth embodiment, the liquid crystal display device 80 according to the sixth embodiment, the liquid crystal display device 90 according to the seventh embodiment, the liquid crystal display device 91 according to the eighth embodiment, Liquid crystal display device 92 according to the tenth embodiment, the liquid crystal display device 93 according to the tenth embodiment, the liquid crystal display device 94 according to the eleventh embodiment, the liquid crystal display device according to the twelfth embodiment, and the thirteenth embodiment. , The liquid crystal display device 110 according to the fourteenth embodiment, and the liquid crystal display device according to the fifteenth embodiment can be applied to various electronic devices. Hereinafter, examples of the application will be described.
[0276]
FIG. 38 is a block diagram of a portable information terminal 250 to which any one of the liquid crystal display devices according to the first to fifteenth embodiments is applied. The liquid crystal display device according to the above embodiment is used as a component of the liquid crystal panel 265 in the portable information terminal 250.
[0277]
The portable information terminal 250 includes a display unit 268 including a liquid crystal panel 265, a backlight generation unit 266, and a video signal processing unit 267 that processes a video signal, and a control unit that controls each component of the portable information terminal 250. 269, a storage unit 271 for storing a program executed by the control unit 269 or various data, a communication unit 272 for performing data communication, an input unit 273 including a keyboard or a pointer, and each of the portable information terminals 250 And a power supply unit 274 for supplying power to the components.
[0278]
By using the liquid crystal panel 265 using the liquid crystal display device according to the above embodiment, the aperture ratio in the display portion 268 can be improved and the luminance of the display portion 268 can be improved.
[0279]
In addition, the liquid crystal panel 265 using any one of the liquid crystal display devices according to the above embodiments can be applied to a monitor of a portable personal computer, a notebook personal computer, or a desktop personal computer.
[0280]
FIG. 39 is a block diagram of a mobile phone 275 to which any one of the liquid crystal display devices according to the above embodiments is applied.
[0281]
The mobile phone 275 includes a display unit 276 including a liquid crystal panel 265, a backlight generation unit 266, and a video signal processing unit 267 that processes a video signal; a control unit 277 that controls each component of the mobile phone 275; A storage unit 278 for storing programs or various data executed by the 277, a receiving unit 279 for receiving a wireless signal, a transmitting unit 281 for transmitting a wireless signal, and an input unit 282 including a keyboard or a pointer. And a power supply unit 283 for supplying power to each component of the mobile phone 275.
[0282]
By using the liquid crystal panel 265 using the liquid crystal display device according to the above embodiment, the aperture ratio of the display portion 276 can be improved, and the luminance of the display portion 276 can be improved.
[0283]
In the description of each of the above embodiments, features that are characteristic of the present invention are mainly described, and matters that are known to those having ordinary knowledge in this field are not particularly described in detail. Even without, these matters belong to the analogy of those mentioned above.
[0284]
【The invention's effect】
In the in-plane switching mode active matrix type liquid crystal display device according to the present invention, the scanning lines and the common electrode wiring are formed in the same layer and in parallel with each other, and the data lines and the scanning lines are formed via an interlayer insulating film. Thus, only one common electrode line is formed on one side of the scanning line.
[0285]
As described above, since the scanning line and the data line are covered with the common electrode with the interlayer insulating film interposed therebetween, the common electrode can shield an electric field leaking from the scanning line and the data line, and the pixel electrode and the common electrode can be shielded. Thus, the effective display area that can be controlled can be enlarged.
[0286]
As a result, the area of the common electrode wiring can be reduced. Specifically, in the conventional IPS mode liquid crystal display device, common electrode wirings are provided on both sides of the scanning line in order to shield a leakage electric field from the scanning line. In the apparatus, since the common electrode has a function of shielding a leakage electric field from the scanning line, it is possible to reduce the number of common electrode wirings for shielding the leakage electric field from the scanning line to one.
[0287]
Further, in the active matrix type liquid crystal display device according to the present invention, since the pixel electrode and the common electrode are formed in different layers, there is no possibility that a short circuit occurs between the two electrodes. Therefore, the production yield of the liquid crystal display device according to the present invention can be improved.
[0288]
In this case, even when compared with the number of steps in the case where the pixel electrode and the common electrode are formed in the same layer as in the conventional IPS mode liquid crystal display device, the steps in the case where the pixel electrode and the common electrode are formed in different layers are compared. The number does not increase.
[Brief description of the drawings]
FIG. 1 is a plan view of an in-plane switching mode active matrix liquid crystal display device according to a first embodiment of the present invention.
FIG. 2 is a sectional view taken along line II-II in FIG.
3 is a circuit diagram of a unit pixel portion of the lateral electric field type active matrix liquid crystal display device shown in FIG.
FIG. 4 is a graph showing characteristics of an in-plane switching mode active matrix liquid crystal display device according to the first embodiment.
FIG. 5 is a graph showing characteristics of the in-plane switching mode active matrix liquid crystal display device according to the first embodiment.
FIG. 6 is a graph showing characteristics of an in-plane switching mode active matrix liquid crystal display device according to the first embodiment.
FIG. 7 is a graph showing characteristics of the in-plane switching mode active matrix liquid crystal display device according to the first embodiment.
FIG. 8A is a schematic plan view for explaining characteristics of an in-plane switching mode active matrix liquid crystal display device according to the first embodiment, and FIG. 8B is a graph showing the characteristics.
FIG. 9 is a cross-sectional view showing each step in the method for manufacturing the in-plane switching mode active matrix liquid crystal display device according to the first embodiment.
FIG. 10 is a cross-sectional view showing each step in the method of manufacturing the in-plane switching mode active matrix liquid crystal display device according to the first embodiment.
FIG. 11 is a cross-sectional view showing each step in the method for manufacturing the in-plane switching mode active matrix liquid crystal display device according to the first embodiment.
FIG. 12 is a plan view of an in-plane switching mode active matrix liquid crystal display device according to a second embodiment of the present invention.
FIG. 13 is a cross-sectional view showing each step in a method for manufacturing an in-plane switching mode active matrix liquid crystal display device according to the second embodiment.
FIG. 14 is a cross-sectional view showing each step in a method for manufacturing an in-plane switching mode active matrix liquid crystal display device according to the second embodiment.
FIG. 15 is a cross-sectional view showing each step in a method for manufacturing an in-plane switching mode active matrix liquid crystal display device according to the second embodiment.
FIG. 16 is a sectional view of an in-plane switching mode active matrix liquid crystal display device according to a third embodiment.
FIG. 17 is a sectional view of an in-plane switching mode active matrix liquid crystal display device according to a fourth embodiment.
FIG. 18 is a cross-sectional view of an in-plane switching mode active matrix liquid crystal display device according to a fifth embodiment.
FIG. 19 is a sectional view of an in-plane switching mode active matrix liquid crystal display device according to a sixth embodiment.
FIG. 20 is a cross-sectional view of an in-plane switching mode active matrix liquid crystal display device according to a seventh embodiment.
FIG. 21 is a plan view of an in-plane switching mode active matrix liquid crystal display device according to an eighth embodiment of the present invention.
FIG. 22 is a sectional view taken along line aa ′ of FIG. 21;
FIG. 23 is a cross-sectional view of a modification of the in-plane switching mode active matrix liquid crystal display device according to the seventh embodiment.
FIG. 24 is a plan view of an in-plane switching mode active matrix liquid crystal display device according to a ninth embodiment of the present invention.
FIG. 25 is a sectional view taken along line bb ′ of FIG. 24;
FIG. 26 is a plan view of an in-plane switching mode active matrix liquid crystal display device according to a tenth embodiment of the present invention.
FIG. 27 is a cross-sectional view taken along the line cc ′ of FIG. 26.
FIG. 28 is a plan view of an in-plane switching mode active matrix liquid crystal display device according to an eleventh embodiment of the present invention.
FIG. 29 is a sectional view taken along line dd ′ of FIG. 28;
FIG. 30 is a schematic plan view showing an example of an arrangement position of a contact hole.
FIG. 31 is a schematic plan view showing an example of an arrangement position of a contact hole.
FIG. 32 is a sectional view of an in-plane switching mode active matrix liquid crystal display device according to a thirteenth embodiment of the present invention.
FIG. 33 is a sectional view of an in-plane switching mode active matrix liquid crystal display device according to a fourteenth embodiment of the present invention.
FIG. 34 is a plan view illustrating an example of a protection circuit.
FIG. 35 is a plan view showing another example of the protection circuit.
FIG. 36 is a plan view showing an example of the shape of a data line.
FIG. 37 is a plan view showing an example of the shape of a data line.
FIG. 38 is a block diagram of an electronic device according to an eleventh embodiment of the present invention.
FIG. 39 is a block diagram of an electronic device according to an eleventh embodiment of the present invention.
FIG. 40 is a plan view of a conventional IPS mode liquid crystal display device.
41 is a sectional view taken along line XX of FIG. 40.
[Explanation of symbols]
10 Liquid crystal display device according to first embodiment
11 Active element substrate
12 Counter substrate
13 Liquid crystal layer
16 Transparent insulating substrate
17 Black matrix layer
18 color layers
19 Overcoat layer
20 scanning lines
20A, 20B Protection circuit wiring
21 Common electrode wiring
22 Transparent insulating substrate
23 Gate insulating film
23a, 23c Contact hole
24 data lines
24A, 24B Protection circuit wiring
25 Pixel electrode
25a Transparent electrode as protective layer
26 Interlayer insulation film
26a Interlayer insulating film made of inorganic film
26b Interlayer insulating film made of organic film
27 Common electrode
28 Spacer
29 Contact hole
38 Pillar pattern
40 Liquid crystal display device according to second embodiment
41, 42 protection circuit
43 conductive pattern
50 Liquid Crystal Display Device According to Third Embodiment
60 Liquid Crystal Display Device According to Fourth Embodiment
70 Liquid Crystal Display Device According to Fifth Embodiment
80 Liquid crystal display device according to sixth embodiment
90 Liquid Crystal Display Device According to Seventh Embodiment
100 Liquid crystal display device according to ninth embodiment
250 portable information terminal
275 mobile phone

Claims (50)

A liquid crystal display device comprising: an active element substrate, a counter substrate, and a liquid crystal layer held between the active element substrate and the counter substrate,
The active element substrate includes a thin film transistor having a gate electrode, a drain electrode, and a source electrode, a pixel electrode corresponding to a pixel to be displayed, a common electrode to which a reference potential is applied, a data line, a scanning line, and a common electrode wiring. With
The gate electrode is electrically connected to the scan line, the drain electrode is connected to the data line, the source electrode is connected to the pixel electrode, and the common electrode is connected to the common electrode wiring, respectively.
Display is performed by rotating the molecular axis of the liquid crystal layer in a plane parallel to the active element substrate by an electric field applied between the pixel electrode and the common electrode and substantially parallel to the surface of the active element substrate. In an in-plane switching type active matrix liquid crystal display device,
The scanning line and the common electrode wiring are formed in the same layer and in parallel with each other,
The data line and the scanning line are covered by the common electrode via an interlayer insulating film,
Only one common electrode wiring is formed on one side of the scanning line,
The common electrode is electrically connected to the common electrode wiring via a contact hole provided in the interlayer insulating film,
The active matrix type liquid crystal display device of a horizontal electric field type, wherein the common electrode is formed so as to shield a gap between the scanning line and the common electrode wiring. In a plan view of a pixel, when a rubbing direction is given in a plan view of a pixel, two corners that give a diagonal line obtained by performing an acute angle rotation in the same direction as the rubbing direction with respect to the extension direction of the data line are provided. The in-plane switching mode active matrix type liquid crystal display device according to claim 1, wherein the active matrix type liquid crystal display device is formed in one of the vicinity. The active matrix liquid crystal display device,
Electric fields in first and second directions substantially parallel to the surface of the active element substrate are applied between the pixel electrode and the common electrode,
An electric field in the first direction is applied, and a first sub-pixel region rotated in a first rotation direction in a plane in which a molecular axis of the liquid crystal layer is parallel to a surface of the active element substrate; An electric field in a second direction is applied, and a second axis rotated in a second rotation direction different from the first rotation direction in a plane in which a molecular axis of the liquid crystal layer is parallel to a surface of the active element substrate. The active matrix type liquid crystal display device of the horizontal electric field system according to claim 1, further comprising: a sub-pixel region. The contact hole forms, in a plan view of a pixel, a direction in which the common electrode wiring extends toward the inside of the pixel and a direction in which the common electrode extends from the common electrode wiring toward the center of the pixel. 4. The in-plane switching mode active matrix type liquid crystal display device according to claim 3, wherein the active matrix type liquid crystal display device is formed at any one of corner positions where the angle is 90 degrees or more. The in-plane switching mode active matrix liquid crystal display device according to claim 1, wherein the common electrode extends at least 3 μm or more from the data line in a width direction thereof. The in-plane switching mode active matrix type liquid crystal display device according to claim 1, wherein the common electrode extends at least 1 μm or more from the scanning line in a width direction thereof. The said common electrode is formed in the layer nearer to the said liquid crystal layer than the said pixel electrode, The said common electrode and the said pixel electrode are mutually electrically insulated by the interlayer insulating film, The Claims characterized by the above-mentioned. The in-plane switching mode active matrix liquid crystal display device according to any one of claims 1 to 6. The in-plane switching mode active matrix type liquid crystal display device according to claim 1, wherein the pixel electrode and the data line are formed in the same layer. The pixel electrode includes: a plurality of first portions; and a second portion interconnecting the plurality of first portions at an end of the first portion.
9. The active-matrix liquid crystal according to claim 1, wherein the second portion is located on the common electrode line and forms a storage capacitor together with the common electrode line. Display device. The active matrix type liquid crystal display device according to claim 9, wherein the second portion of the pixel electrode is separated from a next scanning line by 3 µm or more. 11. The device according to claim 9, wherein the common electrode is formed in a layer closer to the liquid crystal layer than the pixel electrode, and the pixel electrode and the common electrode form a storage capacitor therebetween. 4. An active matrix type liquid crystal display device of a horizontal electric field type according to 1. 12. The in-plane switching mode active matrix liquid crystal display device according to claim 1, wherein the common electrode is formed of a transparent conductive material. The in-plane switching mode active matrix liquid crystal display device according to claim 1, wherein the pixel electrode is formed of a transparent conductive material. The interlayer insulating film is any one of a film made of an organic material, a film made of a transparent inorganic material, and a film having a two-layer structure of a film made of an organic material and a film made of a transparent inorganic material. The active matrix type liquid crystal display device of a horizontal electric field system according to any one of claims 1 to 13. The interlayer insulating film is formed of a stack of an organic film and an inorganic film, and the interlayer insulating film made of the organic film is provided on the scan line and the data line and the common electrode line and the thin film transistor, and the scan line and 14. The in-plane switching mode active matrix liquid crystal display device according to claim 1, wherein the active matrix type liquid crystal display device is formed near the data line, the common electrode line, and the thin film transistor. The interlayer insulating film is formed of a stack of an organic film and an inorganic film, and the interlayer insulating film made of the organic film is provided on the scan line and the data line and the thin film transistor, and the scan line and the data line and 14. The in-plane switching mode active matrix liquid crystal display device according to claim 1, wherein the active matrix type liquid crystal display device is formed near a thin film transistor. The interlayer insulating film is formed by laminating an organic film and an inorganic film, and the interlayer insulating film made of the organic film is formed on the data line and the thin film transistor and in the vicinity of the data line and the thin film transistor. The in-plane switching mode active matrix liquid crystal display device according to any one of claims 1 to 13, wherein: 2. The inter-layer insulating film according to claim 1, wherein the inter-layer insulating film is formed by laminating an organic film and an inorganic film, and the inter-layer insulating film made of the organic film is formed near the data line and the data line. 14. An in-plane switching type active matrix liquid crystal display device according to any one of items 13 to 13. 19. The in-plane switching active matrix liquid crystal display according to claim 15, wherein the interlayer insulating film made of the organic film is formed only inside the pattern of the common electrode. apparatus. 20. The in-plane switching mode active matrix liquid crystal display device according to claim 14, wherein the organic film is made of a photosensitive resin material. 21. The thin film transistor is formed at an intersection of the scanning line and the data line, and the drain electrode of the thin film transistor is directly formed by the data line. An active matrix type liquid crystal display device of a horizontal electric field system according to claim 1. 22. The in-plane switching mode active matrix type liquid crystal display device according to claim 1, wherein the black matrix layer is formed in a matrix. 22. The in-plane switching mode active matrix type liquid crystal display device according to claim 1, wherein the black matrix layer covers the thin film transistor and is formed as an isolated pattern only on the thin film transistor. 24. The in-plane switching mode active matrix type liquid crystal display device according to claim 22, wherein the black matrix layer is made of a material having a specific resistance of 1 × 10 ¹⁰ Ω · cm or more. 25. The in-plane switching mode active matrix liquid crystal display device according to claim 1, wherein a color layer constituting a color filter has an edge parallel to the data line. 26. The color filter according to claim 1, wherein each color layer constituting the color filter is formed with no gap between adjacent color layers or overlaps with adjacent color layers. An in-plane switching type active matrix liquid crystal display device as described above. A columnar pattern formed so as to be arranged at an arbitrary position between the scanning line and the common electrode wiring for securing a gap between the active element substrate and the counter substrate. The active matrix type liquid crystal display device of a horizontal electric field system according to any one of claims 1 to 26. The in-plane switching mode active matrix liquid crystal display device according to any one of claims 1 to 27, wherein the liquid crystal material forming the liquid crystal layer has Δε of 9 or more. The in-plane switching mode active matrix liquid crystal display device according to any one of claims 1 to 27, wherein the liquid crystal material forming the liquid crystal layer has Δε of 11 or more. The in-plane switching mode active matrix type liquid crystal display device according to any one of claims 1 to 29, wherein the liquid crystal material forming the liquid crystal layer has an N / I point of 80 degrees Celsius or more. 31. The common electrode according to claim 1, wherein an opening is formed on a channel of the thin film transistor, and an end of the opening is separated from an end of the channel by a predetermined distance. An in-plane switching mode active matrix liquid crystal display device according to claim 1. In the sub-pixel region where the rotation direction of the liquid crystal molecules is the same, the liquid crystal display device further includes a reverse rotation prevention structure that prevents the liquid crystal from rotating in the opposite direction,
In the reverse rotation prevention structure, the relationship between the rubbing axis and the direction of the electric field generated in the sub-pixel region is such that, in all regions in the sub-pixel region, the direction of the electric field is changed by an acute angle rotation in the same direction from the rubbing axis. 32. An in-plane switching method according to claim 1, further comprising an auxiliary electrode provided with an equal potential to at least one of the pixel electrode and the common electrode so as to overlap. Active matrix type liquid crystal display device. The data line is electrically connected to a protection circuit wiring formed in the same layer as the scanning line through a contact hole formed in an insulating film in a peripheral portion of the screen, and the scanning line is connected to a peripheral portion of the screen. 33. The semiconductor device as claimed in claim 1, wherein the portion is electrically connected to a protection circuit wiring formed in the same layer as the data line through a contact hole formed in the insulating film. Item 6. An in-plane switching type active matrix liquid crystal display device. The data line is electrically connected to a protection circuit wiring formed in the same layer as the scanning line by a conductive pattern formed in an upper layer through a contact hole formed in the interlayer insulating film in a peripheral portion of a screen. And the scanning line is connected to a protection circuit wiring formed in the same layer as the data line by a conductive pattern formed in an upper layer through a contact hole formed in the interlayer insulating film in a peripheral portion of a screen. The in-plane switching mode active matrix type liquid crystal display device according to any one of claims 1 to 32, wherein the active matrix type liquid crystal display device is electrically connected. An electronic device equipped with the active matrix liquid crystal display device according to claim 1. A liquid crystal display device comprising: an active element substrate, a counter substrate, and a liquid crystal layer held between the active element substrate and the counter substrate,
The active element substrate includes a thin film transistor having a gate electrode, a drain electrode, and a source electrode, a pixel electrode corresponding to a pixel to be displayed, a common electrode to which a reference potential is applied, a data line, a scanning line, and a common electrode wiring. With
The gate electrode is electrically connected to the scan line, the drain electrode is connected to the data line, the source electrode is connected to the pixel electrode, and the common electrode is connected to the common electrode wiring, respectively.
Display is performed by rotating the molecular axis of the liquid crystal layer in a plane parallel to the active element substrate by an electric field applied between the pixel electrode and the common electrode and substantially parallel to the surface of the active element substrate. In a method of manufacturing an in-plane switching type active matrix liquid crystal display device,
Forming the scanning line and the common electrode wiring in the same layer in parallel with each other, and forming only one common electrode wiring on one side of the scanning line;
Forming an interlayer insulating film on the data lines and the scanning lines;
Forming a contact hole in the interlayer insulating film;
The common electrode is formed on the interlayer insulating film so as to be electrically connected to the common electrode wiring via the contact hole, and to shield a gap between the scanning line and the common electrode wiring. The process of forming,
A method for manufacturing a lateral electric field type active matrix type liquid crystal display device, comprising: 37. The method of claim 36, further comprising forming the pixel electrode and the data line in the same layer. Forming the pixel electrode from a plurality of first portions and a second portion interconnecting the plurality of first portions at an end of the first portion,
38. The method according to claim 36, wherein the second portion is located on the common electrode line, and forms a storage capacitor together with the common electrode line. . 39. The method according to claim 36, further comprising the step of forming the interlayer insulating film from a stacked film of an organic film and an inorganic film. Method. The interlayer insulating film is formed from a stacked film of an organic film and an inorganic film, and the interlayer insulating film made of the organic film is formed on the scanning line and the data line and the common electrode wiring and the thin film transistor, and the scanning line and the The method of manufacturing an in-plane switching mode active matrix liquid crystal display device according to any one of claims 36 to 38, further comprising a step of forming near the data line, the common electrode line, and the thin film transistor. The interlayer insulating film is formed from a laminated film of an organic film and an inorganic film, and the interlayer insulating film made of the organic film is formed on the scanning line, the data line, and the thin film transistor and the scanning line, the data line, and the thin film transistor The method for manufacturing an in-plane switching mode active matrix liquid crystal display device according to any one of claims 36 to 38, further comprising the step of: Forming the interlayer insulating film from a laminated film of an organic film and an inorganic film, and forming the interlayer insulating film made of the organic film on the data line and the thin film transistor and in the vicinity of the data line and the thin film transistor. 39. The method of manufacturing an in-plane switching mode active matrix liquid crystal display device according to claim 36. A step of forming the interlayer insulating film from a laminated film of an organic film and an inorganic film, and forming the interlayer insulating film made of the organic film on the data line and in the vicinity of the data line. 39. The method for manufacturing a lateral electric field type active matrix liquid crystal display device according to any one of 36 to 38. 44. The in-plane switching mode active matrix liquid crystal display according to claim 36, further comprising a step of forming a black matrix layer as an isolated pattern only on the thin film transistor so as to cover the thin film transistor. Device manufacturing method. The active matrix type of the horizontal electric field system according to any one of claims 36 to 44, further comprising a step of forming a color layer constituting a color filter so as to have an edge parallel to the data line. A method for manufacturing a liquid crystal display device. 37. The method according to claim 36, further comprising the step of forming the color layers constituting the color filter so that each color layer has no gap between adjacent color layers or overlaps with adjacent color layers. 45. The method of manufacturing an in-plane switching mode active matrix liquid crystal display device according to any one of items 45 to 45. A columnar pattern for securing a gap between the active element substrate and the opposing substrate is arranged at an arbitrary position between the scanning line and the common electrode wiring. The method of manufacturing an in-plane switching mode active matrix liquid crystal display device according to any one of claims 36 to 46, further comprising a step of forming the active matrix type liquid crystal display device on a substrate. 37. The method of claim 36, further comprising the step of forming an opening in the common electrode on the channel of the thin film transistor, wherein an end of the opening is separated from an end of the channel by a predetermined distance. 48. The method of manufacturing an in-plane switching mode active matrix liquid crystal display device according to any one of items 47 to 47. The data line is electrically connected to a protection circuit wiring formed in the same layer as the scanning line through a contact hole formed in an insulating film in a peripheral portion of a screen,
A step of electrically connecting the scanning line to a protection circuit wiring formed in the same layer as the data line through a contact hole formed in the insulating film in a peripheral portion of a screen. 49. The method of manufacturing an in-plane switching mode active matrix liquid crystal display device according to any one of items 36 to 48. The data line is electrically connected to a protection circuit wiring formed in the same layer as the scanning line by a conductive pattern formed in an upper layer through a contact hole formed in the interlayer insulating film in a peripheral portion of a screen. And
Electrically connecting the scanning line to a protection circuit wiring formed in the same layer as the data line by a conductive pattern formed through a contact hole formed in the interlayer insulating film in a peripheral portion of a screen. The method of manufacturing an in-plane switching mode active matrix liquid crystal display device according to any one of claims 36 to 48, comprising:

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