JP4182766B2 - Active matrix substrate, electro-optical device, electronic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an active matrix substrate, an electro-optical device including the active matrix substrate, and an electronic apparatus.
[0002]
[Prior art]
In the field of display devices, there is a high need for higher brightness and higher definition, and active matrix display devices are actively researched and developed to meet such needs.
[0003]
By the way, in the above display device, in order to drive the pixel electrodes in a matrix, various wirings such as scanning lines and signal lines on the active matrix substrate on which the pixel electrodes are formed, and thin film transistors (Thin Film Transistors) connected to these wirings. ; TFT) must be formed. In order to supply a sufficient driving voltage to the pixel electrode, a TFT in which a storage capacitor is provided in parallel with the pixel electrode is widely used. However, as a result of forming various wirings and elements in the pixel as described above, the aperture ratio of the pixel is lowered, and problems such as a reduction in display luminance and an increase in power consumption have occurred.
[0004]
For this reason, there has been proposed a structure in which an insulating film is provided on the wiring and TFT, and a pixel electrode is placed on the insulating film.
FIG. 13 is a plan view showing an example of a pixel structure of a conventional liquid crystal device in which a pixel electrode is placed on an insulating film. In the liquid crystal device shown in FIG. 13, thin film transistors (hereinafter abbreviated as TFTs) are provided corresponding to the intersections of the scanning lines SL and the signal lines DL arranged in the vertical and horizontal directions. The capacitor S is conductively connected.
[0005]
The storage capacitor S includes a capacitor electrode S1 and a common capacitor electrode S2 that are opposed to each other with an insulating film interposed therebetween. The capacitor electrode is conductively connected to the TFT, and is further conductively connected to the pixel electrode P through the contact hole H1. On the other hand, the common capacitor electrode S2 is set to a constant potential (for example, a ground potential, a power supply potential, or the same potential as the common electrode potential on the counter substrate side) via an external terminal. These electrodes S1 and S2 have a main line portion provided so as to overlap the scanning line SL in order to increase the aperture ratio, and further, from this main line portion to the signal line DL in order to increase the capacity. It has a branched portion that branches along. The pixel electrode P is provided on the upper layer side of the wirings S1 and DL and the storage capacitor S through an interlayer insulating film. In order to increase the aperture ratio, the end of the pixel electrode P is aligned with the wirings SL and DL. It arrange | positions so that a partial plane may overlap. In FIG. 13, the outline of the pixel electrode P is indicated by a two-dot chain line Pa. In such a structure in which the pixel electrode P is placed on top, a margin between the wirings S1 and DL and the pixel electrode P becomes unnecessary, so that the area of the pixel electrode can be increased.
[0006]
However, when the wirings SL and DL and the pixel electrode P are overlapped in a plane, a new problem arises in that capacitive coupling occurs between them and crosstalk occurs. In particular, since the fluctuation amount of the image signal supplied to the signal line DL is larger than that of the scanning signal SL, a large crossing is caused by capacitive coupling between the signal line DL and the pixel electrode P or the signal line DL and the storage capacitor S. Talk occurs.
Conventionally, as a method for preventing crosstalk, for example, as disclosed in Patent Documents 1 and 2, a method of providing a shield electrode for electrostatic shielding between the pixel electrode P and the signal line DL has been proposed. .
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 5-203994
[Patent Document 2]
JP-A-11-316391
[0008]
[Problems to be solved by the invention]
However, when capacitive coupling between the signal line and the pixel electrode is prevented by adopting the above-described method, the crosstalk in the direction along the signal line can be reduced, but the direction substantially orthogonal to this (that is, along the scanning line). ) Crosstalk.
SUMMARY An advantage of some aspects of the invention is that it provides an active matrix substrate capable of preventing crosstalk, an electro-optical device including the active matrix substrate, and an electronic apparatus.
[0009]
[Means for Solving the Problems]
As a result of intensive studies on the cause of occurrence of crosstalk in the direction orthogonal to the signal line, the present inventors have found that this crosstalk is caused by capacitive coupling between the pixel electrode and the storage capacitor. . That is, in the conventional configuration shown in FIG. 13, the constant-potential-side electrode (that is, the common capacitor electrode) S2 of the storage capacitor S extending in parallel with the scanning line SL and the signal line DL are capacitively coupled, and the signal line The potential of the electrode S2 is fluctuated by an image signal passing through the DL, thereby causing crosstalk in a direction parallel to the electrode S2 (hereinafter, this crosstalk is referred to as lateral crosstalk, and the capacitance between the pixel electrode P and the signal line DL). It was clarified that crosstalk caused by coupling (hereinafter referred to as vertical crosstalk) occurs.
[0010]
As described above, the electrode S2 on the constant potential side has a main line portion extending in parallel with the scanning line SL and a branch portion bent from the main line portion and extending in parallel with the signal line DL in order to increase the storage capacity. In this branch portion, a large capacitive coupling with the signal line DL occurs. When the potential of the electrode S2 is fluctuated by the image signal passing through the signal line DL, the fluctuating potential is attenuated in a certain time. Is written in the storage capacitor S, and the display is greatly disturbed.
[0011]
From the above, the present inventors have come up with the present invention by paying attention to the relationship between the transverse crosstalk and the electric resistance of the constant potential side electrode.
In other words, in order to achieve the above object, an active matrix substrate of the present invention includes a plurality of scanning lines, a plurality of signal lines provided so as to intersect the scanning lines, and the intersection of the scanning lines and the signal lines. A thin film transistor provided corresponding to the portion, a pixel electrode provided corresponding to the thin film transistor, a storage capacitor provided corresponding to the thin film transistor, a layer forming the pixel electrode, and the signal line are formed And an electrostatic shielding electrode conductively connected to an electrode on the constant potential side of the storage capacitor. To do.
[0012]
FIG. 14 shows an example of a planar structure of the active matrix substrate of the present invention. In FIG. 14, for comparison with the conventional structure shown in FIG. 13, only the main part structure of the present invention is different from that in FIG. 13, and the other parts are configured in the same manner as in FIG. 13. The shape and the arrangement of the storage capacitors are not limited to those shown in FIG. Further, in FIG. 14, only the wiring structure is shown and the thin film transistor and other specific layer structures are omitted.
This active matrix substrate is provided with an electrostatic shielding electrode SE between the pixel electrode P (the contour portion is indicated by a two-dot chain line Pa) and the signal line DL in the conventional configuration shown in FIG. The electric shielding electrode SE and the constant potential side electrode S2 of the storage capacitor S are conductively connected. Here, in FIG. 14, the constant potential side electrode S2 and the electrostatic shielding electrode SE are conductively connected through, for example, a contact hole H2.
[0013]
According to this configuration, since the signal line DL is shielded by the electrostatic shielding electrode SE set to a constant potential, the influence (that is, vertical crosstalk) on the pixel electrode potential due to the image signal passing through the signal line DL is suppressed. be able to. On the other hand, since the electrostatic shielding electrode SE is connected to the electrode S2 on the constant potential side of the storage capacitor S to reduce the electrical resistance of the electrode S2, capacitive coupling between the signal line DL and the storage capacitor S is achieved. The resulting lateral crosstalk can also be suppressed. That is, in this configuration, since the electric resistance of the constant potential side electrode S2 of the storage capacitor S is small, even if the potential of the constant potential side electrode S2 is fluctuated by an image signal passing through the signal line DL, this potential fluctuation Will be resolved promptly. Thus, according to the present invention, both vertical crosstalk and horizontal crosstalk can be effectively prevented.
[0014]
Note that it is preferable that the layer for forming the pixel electrode and the layer for forming the signal line overlap with each other in a plan view, whereby the aperture ratio of the pixel can be increased.
Further, the electrostatic shielding electrode has a curved shape, and the electrostatic shielding electrode covers not only the upper end face of the signal line facing the pixel electrode but also at least a part of the side end face adjacent to the upper end face. Such a configuration is preferable. As described above, by surrounding the signal line with the electrostatic shielding electrode, a higher electrostatic shielding effect can be obtained.
[0015]
In order to further reduce the electrical resistance of the constant potential side electrode of the storage capacitor, it is preferable to use a metal material for the electrostatic shielding electrode that is conductively connected to the constant potential side electrode. On the other hand, when priority is given to the brightness of the image, it is preferable to use a conductive member having translucency for the electrostatic shielding electrode. In this case, the periphery of the signal line can be sufficiently covered with the electrostatic shielding electrode without impairing the aperture ratio.
[0016]
In addition, an electro-optical device according to the present invention includes the above-described active matrix substrate and an electro-optical layer stacked on the active matrix substrate. According to this configuration, high-quality display with less crosstalk is possible.
Examples of the electro-optic layer include electro-optic materials such as liquid crystals and electrophoretic substances, and electro-optic elements such as electroluminescence elements.
According to another aspect of the present invention, there is provided an electronic apparatus including the above-described electro-optical device. According to this configuration, it is possible to provide an electronic apparatus including a display unit capable of high-quality display with little crosstalk.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
Hereinafter, an example of the electro-optical device according to the first embodiment of the invention will be described with reference to FIGS. The electro-optical device according to this embodiment is a transmissive liquid crystal device used in a projection liquid crystal display device. FIG. 1 is a diagram for explaining the overall configuration of the liquid crystal device according to the present embodiment. FIG. 2 is a plan view of the TFT array substrate as viewed from the counter substrate side together with the components formed thereon, and FIG. FIG. 3 shows the structure of one pixel of an active matrix substrate on which signal lines, scanning lines, pixel electrodes and the like are formed. FIG. 3 is an equivalent circuit diagram of switching elements and signal lines in a plurality of pixels arranged in a matrix of the device. 4 to 6 are diagrams showing the cross-sectional structure of FIG. 3, FIG. 5 is a cross-sectional view taken along line AA 'in FIG. 3, and FIG. 6 is a cross-sectional view taken along line BB' in FIG. FIG. 7 is a plan view of the main part showing the wiring structure at the end of the display area. In all the drawings below, the scales of the respective layers and members are different in order to make each layer and each member recognizable on the drawings. Therefore, for example, in the case of a member having a width such as a wiring, the widths are shown to be different from each other in the figure, but in actuality, they are formed with the same width, and vice versa. It may be formed with different widths. In the present specification, the surface on the liquid crystal layer side of each member constituting the liquid crystal element is referred to as an “inner surface”, and the opposite surface is referred to as an “outer surface”.
[0018]
As shown in FIG. 1, the liquid crystal device of the present embodiment has a liquid crystal sealed between a pair of substrates, and is a thin film transistor (hereinafter abbreviated as TFT) array substrate (one of which is abbreviated as TFT). An active matrix substrate) 100 and a counter substrate 200 which is the other substrate disposed opposite thereto.
[0019]
A sealing material 51 is provided on the TFT array substrate 100 along the edge thereof, and the substrates 100 and 200 are bonded together via the sealing material 51. In FIG. 1, reference numeral 51 denotes a display area, and reference numeral 53 denotes a non-display area that is an area outside the display area 52. In the non-display area 53, the data line driving circuit 11 and the external circuit connection terminal 12 are provided along one side of the TFT array substrate 100, and the scanning line driving circuit 14 is provided along two sides adjacent to the one side. A precharge circuit 13 is provided along the remaining side. A plurality of wirings 15 for connecting the data line driving circuit 11, the precharge circuit 13, the scanning line driving circuit 14 and the external circuit connection terminal 12 are provided at the end of the substrate. Furthermore, a conductive material 16 for providing electrical continuity between the TFT array substrate 100 and the counter substrate 200 is provided at a position corresponding to the corner portion of the counter substrate 200.
[0020]
As shown in FIG. 2, the display region 52 includes a plurality of scanning lines 120, a plurality of signal lines 110 extending in a direction intersecting the scanning lines 120, and a plurality of signal lines 120 extending in parallel with the signal lines 120. Common capacitance electrode 131 (constant potential side electrode), and a pixel P is provided near each intersection of the scanning line 120 and the signal line 110.
Connected to the signal line 110 is a data line driving circuit 11 and a precharge circuit 13 including a shift register, a level shifter, a video line, and an analog switch. In addition, a scanning line driving circuit 14 including a shift register and a level shifter is connected to the scanning line 120.
[0021]
Each pixel P is supplied with scanning signals G1, G2,..., Gm via a scanning line 120, and a switching thin film transistor (TFT) 140, and an image signal from the signal line 110 via the TFT 140. A pixel electrode 150 supplied with S1, S2,..., Sn, and a storage capacitor 130 connected in parallel to the pixel electrode 150 and holding an image signal for a certain period are provided. The pixel electrode 150 is provided with a common electrode 250 which will be described later, and a liquid crystal sandwiched between the electrodes 150 and 250 by applying a voltage between the pixel electrode 150 and the common electrode 250. The layer (electro-optic layer) 300 is driven.
[0022]
In such a configuration, when pulsed scanning signals G1, G2,..., Gm are applied to the scanning line 120 at a predetermined timing in a line-sequential manner and the TFT 140 is turned on for a certain period, the TFT 140 passes through the TFT 140. Image signals S1, S2,..., Sn are written from the signal line 110 to the pixel electrode 150 at a predetermined timing. The written image signal is applied to the liquid crystal layer 300 through the pixel electrode 150 and held between the common electrode 250 for a certain period. Further, the supplied image signal is held for a certain period by the storage capacitor 130 connected in parallel with the capacitor (liquid crystal capacitor) between the electrodes 150 and 250, thereby preventing leakage of the image signal.
[0023]
The liquid crystal changes the orientation and order of the molecular assembly depending on the applied voltage level, and modulates and outputs the input light. A desired image display is performed by independently controlling the light modulation amount of the liquid crystal for each pixel.
[0024]
Next, based on FIG. 3, the main part planar structure of the present active matrix substrate will be described.
As shown in FIG. 3, on the active matrix substrate 100, rectangular pixel electrodes 150 (outline 150A is indicated by a two-dot chain line) made of a light-transmitting conductive material such as indium tin oxide (ITO) are arranged in a matrix. The signal lines 110, the scanning lines 120, and the common capacitor electrodes 131 are provided along the vertical and horizontal boundaries of the pixel electrode 150. In the present embodiment, each pixel electrode 150 and a region in which the signal line 110, the scanning line 120, the common capacitance electrode 131, the capacitance electrode 132, the electrostatic shielding electrode 160, and the like disposed so as to surround each pixel electrode 150 are formed. Are pixels, and each pixel arranged in a matrix can be displayed independently.
[0025]
The scanning line 120 is disposed so as to face a channel region (an obliquely rising region in the drawing) described later in the semiconductor layer 141, and the scanning line 120 functions as a gate electrode in a portion facing the channel region. To do.
The signal line 110 is conductively connected via a contact hole 450 to a source region described later in the semiconductor layer 141 made of, for example, a polysilicon film constituting the TFT 140.
[0026]
The common capacitor electrode 131 is formed from a main line portion extending in a substantially straight line along the scanning line 120 (that is, a first region formed along the scanning line 120 in a plan view) and a portion intersecting the signal line 110. And a projecting portion projecting upward in the drawing along the signal line 110 (that is, a second region extending along the signal line 110 in a plan view).
[0027]
The capacitor electrode 132 includes a first region that extends substantially linearly along the scanning line 120 and a second region that protrudes forward (upward in the figure) along the signal line 110 from a location that intersects the signal line 110. And is provided in a substantially L shape at each intersection of the signal line 110 and the scanning line 120. In addition, the capacitor electrode 132 is disposed so as to face the common capacitor electrode 131 with a later-described capacitor insulating film 104 interposed therebetween, and a storage capacitor 130 is formed in a region where the electrodes 131 and 132 are opposed to each other. The capacitor electrode 132 is conductively connected to a drain region described later in the semiconductor layer 141 through the contact hole 460. When a scanning signal is applied to the gate electrode and the TFT 140 is turned on, an image signal is supplied from the signal line 110 to the capacitor electrode 132 via the drain region of the TFT 140 and is held in the storage capacitor 130. .
[0028]
The pixel electrode 150 is provided in a substantially rectangular region surrounded by the signal line 110 and the scanning line 120 so that the peripheral portion partially overlaps the wirings 110 and 120 in a plane. The pixel electrode 150 is conductively connected to the intermediate layer 600 through the contact hole 440 and conductively connected to the capacitor electrode 132 through the contact hole 430. As described above, the capacitor electrode 132 is conductively connected to the drain region of the semiconductor layer 141 through the contact hole 460, and the capacitor electrode 132 and the intermediate layer are connected to the pixel electrode 150 from the drain region of the semiconductor layer 141. An image signal is supplied via 600.
[0029]
An electrostatic shielding electrode 160 is provided between the pixel electrode 150 and the signal line 110. The electrostatic shielding electrode 160 (the outline is indicated by a one-dot chain line) is a main line portion extending substantially linearly along the signal line 110 (that is, a first region formed so as to overlap the signal line 110 when seen in a plan view). ) And a protruding portion that protrudes rightward in the drawing along the scanning line 120 from a location that intersects the scanning line 120 (that is, a second region that extends so as to overlap the scanning line 120 in plan view). Have. The electrostatic shielding electrode 160 is conductively connected to the intermediate layer 500 through the contact hole 410 and conductively connected to the common capacitor electrode 131 through the contact hole 420. Further, the line width of the electrostatic shielding electrode 160 (that is, the length in the direction perpendicular to the extending direction of the signal line 110 in the first region and the direction perpendicular to the extending direction of the scanning line 120 in the second region). The length in the direction) is wider than the line width of each of the wirings 110 and 120, so that a sufficient electrostatic shielding effect can be obtained.
[0030]
The light shielding layer 101 is provided on the lower layer side (that is, the display side) of the semiconductor layer 141. The light shielding layer 101 is provided vertically and horizontally along the signal line 110 and the scanning line 120 so as to prevent the return light from entering the semiconductor layer 141 (particularly the channel region) and generating a light leakage current. It has become. The light shielding layer 101 is fixed to a ground potential or a power supply potential through a contact hole (not shown).
[0031]
Next, a cross-sectional structure of the active matrix substrate will be described with reference to FIGS. 4 and 5 are cross-sectional views taken along line AA ′ of FIG. 3, and FIG. 5 is an enlarged view of the active matrix substrate in FIG. FIG. 6 is a cross-sectional view taken along the line BB ′ of FIG. 3 and shows only the active matrix substrate in an enlarged manner.
[0032]
As shown in FIG. 4, the liquid crystal device of this embodiment has a structure in which a liquid crystal layer 300 as an electro-optic layer and a counter substrate 200 are sequentially stacked on an active matrix substrate 100.
The active matrix substrate 100 includes a substrate body 100A made of a translucent material such as glass and quartz, a light shielding layer 101, TFTs and various wirings provided on the inner surface side (liquid crystal layer side) of the light shielding layer 101, The pixel electrode 150 is driven by the TFT, and the alignment film 170 is formed on the entire display area so as to cover the pixel electrode 150. In FIG. 4, illustration of various wirings such as TFTs, scanning lines, and signal lines is omitted.
[0033]
For example, a metal film such as chromium (Cr) is used for the light shielding layer 101, and is laminated on the substrate body 100A by about 200 nm in order to obtain sufficient light shielding properties. Further, in order to insulate the light shielding layer 101 from TFTs and wirings formed thereon, a first interlayer insulating film 102 made of silicon oxide or the like is laminated on the light shielding layer 101 to a thickness of about 800 nm.
[0034]
On the light shielding layer 101, as shown in FIG. 5, a TFT 140, a storage capacitor 130, and a signal line 110 are sequentially laminated.
The TFT 140 is formed by laminating a semiconductor layer 141 made of single crystal silicon or polysilicon, a gate insulating film 142 made of silicon oxide or the like, and a scanning line 120 made of polycrystalline silicon or metal silicide in order from the lower layer side. It is provided at a position facing the light shielding layer 101 through the one interlayer insulating film 102. At this time, the region of the scanning line 120 facing the semiconductor layer 141 functions as a gate electrode.
[0035]
A second interlayer insulating film 103 is stacked on the scanning line 120 to a thickness of about 800 nm, and a capacitor electrode 132 made of polysilicon is 150 nm on the second interlayer insulating film 103 at a position facing the semiconductor layer 141. It is formed to the extent. As described above, the capacitor electrode 132 is conductively connected to the drain region 141c of the semiconductor layer 141 through the contact hole 460, and an image signal is supplied from the signal line 110 through the drain region 141c. ing.
[0036]
A common capacitor electrode 131 is laminated on the capacitor electrode 132 via a capacitor insulating film 104 made of a silicon oxide film or the like. The capacitor electrode 132, the insulating film 104, and the common capacitor electrode 131 store the common capacitor electrode 131. A capacity 130 is configured. Note that the common capacitor electrode 131 has a structure in which a layer 131a made of polysilicon and a layer 131b made of metal silicide are each laminated by about 150 nm. The common capacitor electrode 131 can be set to the same potential as the common electrode 250 on the counter substrate 200 or the same potential as the ground potential or the power supply potential. Yes. Specifically, the common capacitor electrode 131 is conductively connected to the common potential line 17 arranged along the edge of the display region 52 as shown in FIG. The common potential line 17 extends to the vicinity of the corner portion of the counter substrate 200 and is conductively connected to the common electrode 250 of the counter substrate 200 through the conductive material 16. The common potential line 17 is formed in the same layer as the signal line 110, and the common capacitor electrode 131 is conductively connected to the ground line 17 through the contact hole 420.
[0037]
In addition, a third interlayer insulating film 105 is stacked on the common capacitor electrode 131 and the capacitor insulating film 104 to a thickness of about 800 nm, and the third interlayer insulating film 105 is located at a position facing the semiconductor layer 141. A signal line 110 is formed. As described above, the signal line 110 is conductively connected to the sole region 141b of the semiconductor layer 141 through the contact hole 450, and supplies an image signal to the source region 141b. Note that the signal line 110 has a structure in which an aluminum (Al) layer 110a and a titanium nitride (TiN) layer 110b are stacked by about 250 nm and 150 nm, respectively.
[0038]
A fourth interlayer insulating film 106 is stacked on the signal line 110 and the third interlayer insulating film 105 to a thickness of about 400 nm. Further, a position on the fourth interlayer insulating film 106 facing the signal line 110 is electrostatically shielded. An electrode 160 is formed. As described above, the electrostatic shielding electrode 160 has a line width wider than that of the signal line 110. When the storage capacitor 130 and the signal line 110 are sequentially patterned at a position facing the semiconductor layer 141, a region facing the semiconductor layer 141 in the central portion of the fourth interlayer insulating film 106 stacked on the signal line 110 (that is, The region facing the signal line 110 is raised more than the peripheral region. Therefore, the electrostatic shielding electrode 160 formed on the fourth interlayer insulating film 106 has a shape in which the central portion 160T is curved in a convex shape with respect to the peripheral portion 160S, and the end surface of the signal line 110 facing the pixel electrode 150. 111 and the side end face 112 adjacent thereto are encased (covered) by the electrostatic shielding electrode 160. In other words, in the present embodiment, as shown in FIG. 5, the end surface 111 of the signal line 110 on the liquid crystal layer side is formed with a central portion 160 </ b> T formed in a convex shape of the electrostatic shielding electrode 160 via the fourth interlayer insulating film 106. In addition, both side end surfaces 112 of the signal line 110 are opposed to the peripheral portion 160 </ b> S of the electrostatic shielding electrode 160 through the fourth interlayer insulating film 106. In this way, by providing the electrostatic shielding electrode 160 to a position that wraps around the side end face 112 of the signal line 110, crosstalk (vertical crosstalk) caused by capacitive coupling between the signal line 110 and the pixel electrode 150 is more effective. Can be prevented.
[0039]
Further, as shown in FIG. 6, the electrostatic shielding electrode 160 is conductively connected to the intermediate layer 500 formed on the fourth interlayer insulating film 105 through the contact hole 410, and this intermediate layer 500 is further connected. Is conductively connected to the common capacitor electrode 131 through the contact hole 420. At the same time, the electrostatic shielding electrode 160 is conductively connected to the common potential line 17 through the contact hole 410 at the end of the display area 52 (see FIG. 7). Thereby, the electrostatic shielding electrode 160 is set to the same potential as the common electrode 250 on the counter substrate 200 together with the common capacitance electrode 131. Further, since the electrostatic shielding electrode 160 is connected in parallel to the common capacitance electrode 131, it plays a role of reducing the electric resistance of the common capacitance electrode 131. As a result, even if the potential of the common capacitor electrode 131 is changed by an image signal passing through the signal line 110, the potential change can be quickly reduced. The electrostatic shielding electrode 160 has a structure in which an Al layer 160a and a TiN layer 160b are stacked by about 250 nm and 150 nm, respectively. Thus, by using a metal material having a lower electric resistance than the common capacitor electrode 131 for the electrostatic shielding electrode 160, the electric resistance of the common capacitor electrode 131 of the storage capacitor 130 can be further reduced.
[0040]
A fifth interlayer insulating film 107 is stacked on the electrostatic shielding electrode 160 and the fourth interlayer insulating film 106 to a thickness of about 600 nm. Further, a substantially rectangular pixel electrode 150 is formed on the fifth interlayer insulating film 107 in a matrix. A plurality are formed. As described above, the pixel electrode 150 is conductively connected to the intermediate layer 600 through the contact hole 440 and conductively connected to the capacitor electrode 132 through the contact hole 430. Further, it is conductively connected to the drain region 141 c of the semiconductor layer 141 through the contact hole 460. Note that the intermediate layer 500 and the intermediate layer 600 are provided in the same layer as the signal line 110 (that is, on the fourth interlayer insulating film 106), and are simultaneously patterned when the signal line 110 is formed.
On the pixel electrode 150 and the fifth interlayer insulating film 107, an alignment film 170 for defining the alignment state of liquid crystal molecules when no voltage is applied is formed.
[0041]
On the other hand, as shown in FIG. 4, the counter substrate 200 covers a substrate body 200A made of a light-transmitting material such as glass, quartz, or resin, a light shielding layer 201 formed in a non-pixel region, and the light shielding layer 201. The transparent common electrode 250 is formed on the entire display area, and the alignment film 270 is formed on the entire display area so as to cover the common electrode 250.
[0042]
The above-described substrates 100 and 200 are held in a state of being separated by a predetermined substrate interval (gap) by a spacer (not shown), and are bonded by a sealing material 51 provided on the peripheral edge of the substrate. The liquid crystal is sealed in a space sealed by the substrates 100 and 200 and the sealing material, thereby forming a liquid crystal device. Note that in the case where a polymer dispersed liquid crystal is used for the liquid crystal layer 300, the alignment films 170 and 270 can be omitted.
[0043]
Therefore, according to the electro-optical device of this embodiment, since the electrostatic shielding electrode 160 is disposed between the pixel electrode 150 and the signal line 110, the fluctuation of the image signal passing through the signal line 110 becomes the pixel electrode potential. It is possible to prevent the influence from being exerted. Further, since the electrostatic shielding electrode 160 is conductively connected to the common capacitance electrode 131 of the storage capacitor 130 to reduce the electric resistance of the common capacitance electrode 131, the potential of the common capacitance electrode 131 passes through the signal line 110 temporarily. Even when the fluctuation is caused by the image signal, the fluctuation potential can be quickly eliminated. Accordingly, both vertical crosstalk and horizontal crosstalk can be prevented with a simple configuration, and high-quality image display is possible.
Further, in the present liquid crystal device, the curved electrostatic shielding electrode 160 is disposed so as to cover the signal line 110, and the electrostatic shielding electrode 160 is configured to wrap up to the side end face 112 of the signal line 110. A higher electrostatic shielding effect can be obtained.
[0044]
[First Modification]
Next, a liquid crystal device according to a first modification of the present invention will be described with reference to FIG.
In this modification, the formation area of the electrostatic shielding electrode is expanded more than that of the first embodiment, and the electrostatic shielding electrode 160 ′ is extended to the upper area of the intermediate layer 600. In this way, the electrostatic shielding electrode 160 ′ is positively extended to a position where it overlaps with the right intermediate layer 600, so that the gap is formed between the intermediate layer 500 and the intermediate layer 600 which are the gaps in the first embodiment. It is possible to prevent the characteristics of the common capacitor electrode 131 from being deteriorated by the invading light.
[0045]
[Second Modification]
Next, a liquid crystal device according to a second modification of the present invention will be described with reference to FIG.
In this modification, the electrostatic shielding electrode 161 extends along the scanning line from a position intersecting the main line portion (first region) formed so as to overlap the signal line 110 and the scanning line (not shown). And a projecting portion projecting left and right (that is, a second region branched so as to overlap the scanning line in a planar manner). Thus, by forming the electrostatic shielding electrode 161 in a cross shape, the light shielding property to the common capacitor electrode 131 and the semiconductor layer 141 disposed on the lower layer side can be further enhanced.
[0046]
[Third Modification]
Next, a liquid crystal device according to a third modification of the present invention will be described with reference to FIG.
In this modification, in the configuration of the second modification, protrusions of adjacent electrostatic shielding electrodes are connected to each other. In other words, in this modification, the electrostatic shielding electrode 162 is formed so as to overlap the first main line portion 1621 formed so as to overlap the signal line 110 and the scanning line (not shown). And a second main line portion 1622. The second main line portion 1622 is conductively connected to the common potential line 17 through the contact hole 410 at the end of the display region 52.
Thus, in this modification, since the electrostatic shielding electrode 162 is provided corresponding to both the scanning line and the signal line 110, the electrostatic shielding ability and the light shielding ability can be maximized. Further, since the electrostatic shielding electrode 162 is conductively connected not only to the first main line portion 1621 but also to the second main line portion 1622 to the common potential line 17, the electric resistance of the common capacitor electrode 131 can be further reduced. it can.
[0047]
[Electronics]
Next, an example of an electronic apparatus including the above-described electro-optical device will be described.
FIG. 11 is a plan view illustrating a configuration of a projection display device including the above-described electro-optical device as a light valve. The projection display device 1110 is prepared as a projector using three modules including the liquid crystal device (electro-optical device) 100 including the active matrix substrate described above, and used as the RGB light valves 100R, 100G, and 100B. Has been. In this liquid crystal projector 1110, when light is emitted from a lamp unit 1112 of a white light source such as a metal halide lamp, light corresponding to the three primary colors R, G, and B is emitted by three mirrors 1116 and two dichroic mirrors 1118. The light components are separated into components R, G, and B (light separating means) and led to the corresponding light valves 100R, 100G, and 100B (liquid crystal device 100 / liquid crystal light valve). At this time, since the optical component B has a long optical path, the light component B is guided through a relay lens system 1131 including an incident lens 1132, a relay lens 1123, and an exit lens 1134 in order to prevent light loss. Then, the light components R, G, and B corresponding to the three primary colors respectively modulated by the light valves 100R, 100G, and 100B are incident on the dichroic prism 1122 (light combining means) from three directions and are combined again, and then the projection lens. A color image is projected onto a screen 1130 or the like via 1124.
In the above-described electronic apparatus, since the above-described active matrix substrate is used for the electro-optical device that outputs image light, high-quality image display in which crosstalk is prevented is possible.
[0048]
In addition, this invention is not limited to the above-mentioned embodiment, It can implement in various deformation | transformation in the range which does not deviate from the meaning of this invention.
For example, in the above-described embodiment, the material and thickness of each layer (or each film) are specifically shown, but the present invention is not limited to this, and can be changed according to the application.
[0049]
In the above embodiment, a metal material having conductivity equal to or higher than that of the common capacitor electrode 131 is used for the electrostatic shielding electrode 160. However, a material having lower conductivity than the common capacitor electrode may be used. . Even in this case, since the electric resistance of the common capacitor electrode is reduced, the effect of the present invention can be obtained. Specifically, a light-transmitting conductive material such as ITO can be used as the electrostatic shielding electrode. Thus, when a transparent member is used for the electrostatic shielding electrode, the aperture ratio does not decrease due to the provision of the electrostatic shielding electrode. For this reason, a higher electrostatic shielding effect can be obtained by providing an electrostatic shielding electrode having a sufficiently wider line width than the signal line 110.
[0050]
In the above embodiment, the electro-optical device is described as a liquid crystal device. However, the present invention is not limited to this, and the electrophoretic device, electroluminescence (EL), digital micromirror device (DMD), plasma emission, and electron Needless to say, the present invention can also be applied to various devices using fluorescence by emission. In this case, the electro-optical device may be either a reflection type or a transmission type display device.
[0051]
【Example】
In order to demonstrate the effect of the present invention, the present inventors confirmed the electrical characteristics of the active matrix substrate according to the present invention by device simulation. The results are reported below.
[0052]
In this example, the structure of the above-described embodiment is employed as the active matrix substrate, and the material and thickness of each layer are configured in accordance with the description of the above-described embodiment. Then, the size of the coupling capacitance between the pixel electrode and the signal line was simulated when the line width ALB of the electrostatic shielding electrode was fixed to 3 μm and the line width ALA of the signal line was changed (see FIG. 12). In FIG. 12, the coupling capacitance is normalized based on the coupling capacitance in a configuration in which the signal line width ALA is 3 μm and no electrostatic shielding electrode is provided, and the size is shown in percentage.
[0053]
From the simulation results of FIG. 12, it can be seen that the coupling capacitance between the pixel electrode and the signal line greatly depends on the relative size (line width difference) between the electrostatic shielding electrode and the signal line. For example, the coupling capacitance when the line width of the signal line is about 3.8 μm (that is, when both sides of the signal line protrude from the side of the electrostatic shielding electrode by 0.4 μm when viewed in plan) is It can be seen that the size is the same as when no electrostatic shielding electrode is provided, and no electrostatic shielding effect is obtained. In addition, when the line width of the signal line is set to 3 μm as the line width of the electrostatic shielding electrode (that is, the electrostatic shielding electrode completely overlaps the signal line when viewed in plan), the electrostatic shielding electrode The coupling capacity is reduced to about one third as compared with the configuration in which no is provided. Furthermore, the line width of the signal line is about 2 μm (that is, when viewed in plan, both sides of the electrostatic shielding electrode protrude by 0.5 μm from the side of the signal line, and the protruding end portion of the side of the signal line In the case of being covered so as to be encased), the coupling capacitance is reduced to 1/10 or less compared to the case where no electrostatic shielding electrode is provided.
Thus, it can be seen that a large shielding effect can be obtained by arranging the electrostatic shielding electrode formed in a convex shape so as to cover the signal line.
[Brief description of the drawings]
FIG. 1 is a plan view of an electro-optical device according to a first embodiment of the invention.
FIG. 2 is an equivalent circuit diagram of the electro-optical device.
FIG. 3 is a plan view of an active matrix substrate of the electro-optical device.
4 is a cross-sectional view taken along the line AA ′ of FIG. 3. FIG.
FIG. 5 is an enlarged view of a main part of FIG. 4;
6 is an enlarged view of a main part showing a BB ′ cross section of FIG. 3. FIG.
FIG. 7 is a plan view of an essential part of the active matrix substrate.
FIG. 8 is a cross-sectional view of an electro-optical device according to a first modified example of the invention.
FIG. 9 is a cross-sectional view of an electro-optical device according to a second modified example of the invention.
FIG. 10 is a cross-sectional view of an electro-optical device according to a third modified example of the invention.
FIG. 11 illustrates an example of an electronic apparatus according to the invention.
FIG. 12 is a simulation result of a coupling capacitance between a pixel electrode and a signal line.
FIG. 13 is a plan view showing a pixel structure of a conventional active matrix substrate.
14 is a plan view showing a characteristic part of the present invention in comparison with FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 ... Active matrix substrate, 110 ... Signal line, 120 ... Scanning line, 130 ... Storage capacitor, 131 ... Common capacity electrode (constant potential side electrode), 140 ... Thin film transistor, 150 ... Pixel electrode, 160 ... Electrostatic shielding electrode, 111 ... Upper end face, 112 ... Side end face, 300 ... Liquid crystal layer (electro-optic layer)

Claims (7)

A plurality of scan lines;
A plurality of signal lines provided crossing the scanning line;
A thin film transistor provided corresponding to an intersection of the scanning line and the signal line;
A pixel electrode provided corresponding to the thin film transistor;
A storage capacitor provided corresponding to the thin film transistor;
It is provided between the layer for forming the pixel electrode and the layer for forming the signal line, and is provided so as to overlap the signal line in plan view, and is electrically connected to the electrode on the constant potential side of the storage capacitor. An active matrix substrate comprising an electrostatic shielding electrode. 2. The active matrix substrate according to claim 1, wherein the layer forming the pixel electrode and the layer forming the signal line are arranged so as to partially overlap in a plan view. The electrostatic shielding electrode is provided to cover an upper end face of the signal line facing the pixel electrode and to cover at least a part of a side end face adjacent to the upper end face. Item 3. The active matrix substrate according to Item 1 or 2. The active matrix substrate according to claim 1, wherein the electrostatic shielding electrode is made of a metal material. The active matrix substrate according to any one of claims 1 to 4, wherein the electrostatic shielding electrode is made of a conductive member having translucency. An active matrix substrate according to any one of claims 1 to 5,
An electro-optical device comprising: an electro-optical layer laminated on the active matrix substrate. An electronic apparatus comprising the electro-optical device according to claim 6.

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