JP4004781B2 - Active matrix display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an active matrix display device, and more particularly to a technique for preventing display defects even when electrostatic breakdown occurs in an active matrix display device using a liquid crystal, an organic EL (Electroluminescence) element, or the like.
[0002]
[Prior art]
A liquid crystal display panel is advantageous in that it is thin and lightweight, can be driven at a low potential and consumes less power, and is widely used in various electronic devices. In particular, an active matrix type liquid crystal display device in which a switching element such as a TFT element (Thin Film Transistor) is provided for each pixel is superior in terms of display quality to comparable to a CRT (Cathode-Ray Tube). Therefore, it is used for displays such as portable televisions and personal computers.
[0003]
As shown in FIG. 7, a general TN (Twisted Nematic) type liquid crystal display panel includes a TFT substrate 110 on which TFT elements and pixel electrodes are formed, and a CF on which a black matrix, a color filter, a common electrode, and the like are formed. The substrate 111 is disposed so as to face the substrate, and a liquid crystal is sealed between the two substrates 110 and 111. A TFT substrate side polarizing plate 118 and a CF substrate side polarizing plate 120 are attached to the surface opposite to the opposing surface of the TFT substrate 110 and the CF substrate 111, respectively. A backlight light source 116 is disposed behind the TFT substrate side polarizing plate 118.
[0004]
These two polarizing plates 118 and 120 are, for example, arranged so that the polarizing axes of the polarizing plates are orthogonal to each other. According to this, light is transmitted when no electric field is applied, and light is blocked when an electric field is applied. Mode, that is, normally white mode. When the polarization axes of the two polarizing plates 118 and 120 are parallel, the light is blocked when no voltage is applied, and the mode is a normally black mode in which light is transmitted when a voltage is applied.
[0005]
A gate driving circuit 112 and a drain driving circuit 114 are provided on the peripheral portion of the TFT substrate 110, and the gate driving circuit 112 and the drain driving circuit 114 are connected to the control circuit 122.
[0006]
FIG. 8 is a plan view showing an example of a matrix circuit formed on the TFT substrate 110. As shown in FIG. 8, the TFT substrate 110 is provided with a plurality of gate bus lines 124 extending in the horizontal direction and a plurality of drain bus lines 126 extending in the vertical direction on the insulating glass substrate 136. A region is defined. A transparent pixel electrode 128 is formed in the pixel region, and a storage capacitor bus line 130 is formed across the pixel region almost at the center of the pixel electrode 128.
[0007]
In addition, a TFT element 132 is provided on the top of each pixel region. The drain portion of the TFT element 132 is electrically connected to the drain bus line 126, and the source portion of the TFT element 132 is electrically connected to the pixel electrode 128. In this way, the circuit element 133 is formed by forming a pixel as a display unit by three pixel regions (sub-pixels) of a red (R) pixel, a green (G) pixel, and a blue (B) pixel. .
[0008]
Then, image information is supplied from the control circuit 122 to the gate driving circuit 112 and the drain driving circuit 114, and all the pixel electrodes are passed from the gate driving circuit 112 and the drain driving circuit 114 via the TFT elements 132 at a predetermined timing. A gradation voltage is sequentially applied to 128 to display an image.
[0009]
Incidentally, since the TFT substrate 110 is made of an insulating glass substrate 136, static electricity may be generated due to various causes during the manufacturing process of the TFT substrate 110. For example, when the TFT substrate 110 is attached to or removed from various processing devices, transfer devices, or substrate holders, static electricity may invade the TFT substrate 110 by being charged by friction, adsorption, or peeling. is there.
[0010]
Further, due to various plasma processes used when manufacturing the TFT element 132 and the like on the TFT substrate 110, for example, a plasma CVD process, a sputtering process, and a reactive ion etching (RIE) process, Static electricity may accumulate in
[0011]
Conventionally, in order to avoid such a problem, this electrostatic protection is achieved by connecting an electrostatic protection element such as a transistor or a resistor between a power supply line connected to the circuit element 133 of the TFT substrate 110 and a ground line. Measures such as preventing a high electric field from being applied to the circuit element 133 of the TFT substrate 110 have been taken by absorbing a rapid change in the electric field by the element.
[0012]
[Problems to be solved by the invention]
However, the electric charge generated by the discharge generated between the TFT substrate 110 and the outside of the TFT flows through the low resistance portion of the TFT substrate 110. In particular, a conductive film having a low resistance such as the source electrode and the drain electrode of the TFT element 132 is used. In the case where the conductive film patterns are formed separately, a portion where the distance between the conductive film patterns is narrow or a portion where the end portion of the conductive film pattern is sharply flows preferentially as a current path. In the current path, the portion with the highest resistance is destroyed by using energy. That is, even if an electrostatic protection element is provided as in the prior art, it is difficult to completely prevent electrostatic breakdown of the TFF element.
[0013]
More specific description will be given below. FIG. 9A is an enlarged plan view of one pixel region of FIG. 8, and FIG. 9B is a cross-sectional view taken along II-II of FIG. 9A. In FIG. 9, the same elements as those of FIG. As shown in FIG. 9B, the cross-sectional structure of the TFT element 132 has a gate bus line 124 (a gate electrode of the TFT element 132), a gate insulating film 140, and an amorphous silicon film 141 in order from the bottom on the glass substrate 136. A channel protective film 144 is formed, and a source electrode 143 and a drain electrode 142 electrically connected to the source part and the drain part of the amorphous silicon film 141 are formed.
[0014]
A protective insulating film 146 is formed over the source electrode 143 and the drain electrode 142, a contact hole 148 is formed in the protective insulating film 146 over the source electrode 143, and the source electrode 143 and the pixel electrode 128 are connected to the contact hole 148. It is electrically connected via.
[0015]
As shown in FIG. 9A, a storage capacitor bus line 130 is formed at the center of the pixel region, and an intermediate electrode 131 is formed above the storage capacitor bus line 130. The intermediate electrode 131 and the pixel electrode 128 are electrically connected through a contact hole 148 a formed in the protective insulating film 146.
[0016]
By the way, in the TFT element 132, in order to improve the transistor characteristics, the interval between the drain electrode 142 and the source electrode 143 is formed to be 3 μm or less, for example, about 2.5 μm, and the layout of the conductive film pattern in the circuit element 133 is reduced. Of these, the narrowest is designed. Further, the drain electrode 142 and the source electrode 143 of the TFT element 132 have sharp portions (an angle of about 90 °) (J portion and K portion in FIG. 9A). Furthermore, the drain electrode 142 and the source electrode 143 of the TFT element 132 are made of a metal film having a low resistance, and are connected via the amorphous silicon film 41 having a high resistance.
[0017]
That is, since the TFT element 132 exemplified above satisfies all of the above-described conditions that are liable to cause electrostatic breakdown, the electric charge generated by the discharge generated between the TFT substrate 110 and the outer periphery thereof passes through the amorphous silicon film 141. The current flows preferentially between the drain electrode 142 and the source electrode 143 as a current path. At this time, a current flows preferentially through both ends of the pattern where the drain electrode 142 and the source electrode 143 face each other (J and K portions in FIG. 9).
[0018]
As a result, the current generated by static electricity destroys the amorphous silicon film 41 using energy in the amorphous silicon film 41 having a high resistance. When the amorphous silicon film 41 serving as the channel portion of the TFT element 132 is thus destroyed, the TFT element 132 does not function, and as a result, the pixel portion related to the TFT element 132 becomes a display defect. is there.
[0019]
In JP-A-8-62615, a protrusion is provided on an input terminal (pad) outside the display unit, and static electricity is discharged preferentially at this portion to store a storage capacitor bus line and a gate bus line in the display unit. And preventing a short circuit between the drain bus lines. Japanese Patent Application Laid-Open No. 6-18924 discloses that input terminals are arranged close to each other and defects caused by static electricity are prevented by capacitive coupling between these input terminals.
[0020]
However, each of these methods has an effect of preventing the occurrence of defects due to static electricity generated outside the display portion, but the effect of preventing the occurrence of defects due to static electricity generated within the display portion is small.
[0021]
The present invention was created in view of the above problems, and an object of the present invention is to provide an active matrix display device that can prevent electrostatic breakdown of a TFT element due to static electricity, and thus can prevent display defects. To do.
[0022]
[Means for Solving the Problems]
In order to solve the above problems, the present invention relates to an active matrix display device, and in an active matrix display device including a nonlinear element for each pixel, any one of a source electrode of the nonlinear element and a conductive film connected to the source electrode is provided. The source electrode, the conductive film, and the source electrode, the conductive film, and the drain bus line connected to the drain electrode of the nonlinear element are narrower than a distance between the drain electrode and the source electrode of the nonlinear element. A protrusion is provided on at least one of the drain bus lines.
[0023]
When current flows due to static electricity on an insulating glass substrate (TFT substrate) on which a TFT element, which is an example of a nonlinear element, is formed, a drain bus line made of a low-resistance metal film, and a drain of the TFT element connected to the drain bus line The current flows intensively to the electrode and the source electrode of the TFT element. Moreover, in order to improve the transistor characteristics of the TFT element, the distance between the drain electrode and the source electrode is designed to be the narrowest among other circuit element patterns.
[0024]
Furthermore, since the drain electrode and the source electrode are connected via a high-resistance amorphous silicon film that becomes a channel portion of the TFT element, the gap between the drain electrode and the source electrode via the amorphous silicon film is A current flows as a current path. At this time, the current generated by static electricity destroys part of the amorphous silicon that is the channel portion of the TFT element by using energy in the high-resistance amorphous silicon film, so that the TFT element does not function.
[0025]
According to the present invention, for example, the current between the TFT element source electrode and the data bus line is made narrower than the distance between the TFT element drain electrode and the source electrode, so that even if current flows through the TFT substrate due to static electricity, the TFT element A region other than the data bus line and the source electrode of the TFT element forms a static current path, and the high-resistance protective insulating film interposed therebetween is destroyed. Alternatively, the distance between the conductive film (eg, pixel electrode or intermediate electrode) connected to the source electrode of the TFT element and the data bus line may be narrower than the distance between the drain electrode and the source electrode of the TFT element.
[0026]
As a result, even if a current flows through the TFT substrate due to static electricity, there is no risk of the TFT element being destroyed, so that display defects due to static electricity can be prevented from occurring.
[0027]
In order to solve the above problem, the present invention relates to an active matrix display device, and a plurality of TFT elements each having a drain electrode connected to one drain bus line and a source electrode connected to one pixel electrode for each pixel. And the interval between the drain electrode and the source electrode is different among the plurality of TFT elements.
[0028]
According to the present invention, for example, two TFT elements are formed in one pixel, both of which have a drain electrode connected to a common drain bus line and a source electrode connected to a common pixel electrode. ing. Of these two TFT elements, one TFT element is a regular TFT element formed according to a desired design rule, and the other TFT element is formed as a pseudo (dummy) TFT element. For example, the interval between the drain electrode and the source electrode of the pseudo TFT element is formed so as to be narrower than the interval between the drain electrode and the source electrode of the normal TFT element.
[0029]
In this way, when a current flows through the TFT substrate due to static electricity, when there is a conductive film pattern formed separately as described above, the current is preferentially used as a current path in a portion where the interval is narrow. Since the current flows, a current flows between the drain electrode and the source electrode of the pseudo TFT element as a current path, and as a result, the pseudo TFT element is electrostatically destroyed. Therefore, even if a current flows through the TFT substrate due to static electricity, it is possible to prevent the normal TFT element from being electrostatically destroyed.
[0030]
For example, out of two TFT elements formed in one pixel region, knowing which thin film transistor is a dummy thin film transistor in which the distance between the drain electrode and the source electrode is narrow. Even after the assembly, a pseudo TFT element that has been electrostatically damaged from the back side of the TFT substrate can be repaired by cutting it from the drain bus line.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0032]
(First embodiment)
FIG. 1A is a partial plan view showing a TFT substrate of a liquid crystal display panel according to the active matrix display device of the first embodiment of the present invention, and FIG. 1B is taken along II of FIG. FIG.
[0033]
As shown in FIG. 1A, the TFT substrate 10 of the liquid crystal display panel of this embodiment includes a plurality of gate bus lines 24 extending in the horizontal direction and a plurality of drains extending in the vertical direction on an insulating glass substrate 36. A bus line 26 is provided, and these define a pixel region. A pixel electrode 28 made of a transparent ITO (Indium Tin Oxide) film is formed in the pixel region, and a storage capacitor bus line 30 is formed across the pixel region almost at the center of the pixel electrode 28. An intermediate electrode 31 is formed above the storage capacitor bus line 30. The intermediate electrode 31 and the pixel electrode 28 are electrically connected through a contact hole 48a formed in the protective insulating film. The intermediate electrode 31 and the storage capacitor bus line 30 form a storage capacitor.
[0034]
A TFT element 32, which is an example of a non-linear element, is provided above the pixel region. A drain electrode 42 is formed at the drain portion of the TFT element 32, and the drain electrode 42 is connected to the drain bus line 26. Further, a source electrode 43 is formed in the source portion of the TFT element 32, and the source electrode 43 is electrically connected to the pixel electrode 28 through a contact hole 48 formed in the protective insulating film. Note that FIG. 1A illustrates one pixel region of the TFT substrate, and a pixel that is a display unit in three pixel regions of a red (R) pixel, a green (G) pixel, and a blue (B) pixel. Configure.
[0035]
As shown in FIG. 1B, the cross-sectional structure of the TFT element 32 has a gate bus line 24 (a gate electrode of the TFT element 32), a gate insulating film 40, an amorphous silicon film (on the glass substrate 36 in order from the bottom). (Or a polysilicon film) 41 and a channel protective film 44, and further, a source electrode 43 and a drain electrode 42 connected to the source part and the drain part of the amorphous silicon film 41, respectively. A protective insulating film 46 is formed on the source electrode 43 and the drain electrode 42, a contact hole 48 is formed in the protective insulating film 46 on the source electrode 43, and the source electrode 43 and the pixel electrode 28 are connected to the contact hole 48. It is electrically connected via.
[0036]
One of the features of the active matrix display device according to the first embodiment of the present invention is that, for example, as shown in FIG. 1A, by providing a convex portion 43a on the drain bus line 26 side of the source electrode 43, the source An interval between the electrode 43 and the drain bus line 26 (A portion in FIG. 1A) is made narrower than an interval between the source electrode 43 and the drain electrode 42 of the TFT element 32 (C portion in FIG. 1A). .
[0037]
Conventionally, the distance between the source electrode 43 and the drain electrode 42 (C portion in FIG. 1A) is about 2.5 μm, and the distance between the source electrode 43 and the drain bus line 26 (A portion in FIG. 1A). In the present embodiment, the distance between the source electrode 43 and the drain bus line 26 (the A part in FIG. 1A) is narrower than the C part, for example, 2.0 μm. To the extent. Of course, the interval between the A part and the C part can be appropriately changed.
[0038]
Similarly to the above-described A part, the interval between the intermediate electrode 31 connected to the source electrode 43 of the TFT element 32 via the pixel electrode 28 and the data bus line 26 (B part in FIG. 1A) is defined as C. It is narrower than the interval between the parts. In addition, in this embodiment, although the space | interval of both A part and B part is illustrated as a form narrower than the space | interval of C part, one space | interval is compared with the space | interval of C part among space | intervals of A part and B part. It is good also as a narrowed form.
[0039]
A current accompanying discharge due to static electricity generated between the insulating TFT substrate 10 and the periphery of the TFT substrate 10 preferentially flows through a portion of the TFT substrate 10 such as a metal film having a low resistance. In addition, when a metal film with low resistance is formed separately through a high resistance film, this current is a current path with a portion where the distance between the metal film patterns is narrow or a pointed portion of the opposing metal film pattern. It flows preferentially. In the current path, the highest resistance portion of the current path uses energy to destroy the high resistance portion.
[0040]
As shown in FIG. 1B, the TFT element 32 in FIG. 1A has a low resistance drain made of a metal film such as an alloy film of aluminum (Al) and chromium (Cr) or a titanium (Ti) film. Since the electrode 42 and the source electrode 43 are connected to each other through an amorphous silicon film 41 having a higher resistance than the electrode 42 and the source electrode 43, when this portion becomes a current path accompanying discharge due to static electricity, the amorphous silicon film 41 is electrostatically charged. The TFT element 32 will not function due to destruction.
[0041]
In the present embodiment, in order to avoid this problem, the distance between the drain bus line 26 and the source electrode 42 (see FIG. 1) from the distance between the drain electrode 42 and the source electrode 43 of the TFT element 32 (part C in FIG. 1A). 1 (a) A portion) is made narrower. For this reason, a current accompanying discharge due to static electricity flows as a current path between the source electrode 42 and the drain bus line 26 having a narrow interval, and the high-resistance gate insulating film 40 interposed between the source electrode 42 and the drain bus line 26. Alternatively, the protective insulating film 46 is electrostatically destroyed ((A part in FIG. 1A). Even if the gate insulating film 40 or the protective insulating film 46 in this part is electrostatically destroyed, no display defect is caused. It is possible to prevent display defects of the liquid crystal display panel.
[0042]
When the interval between the intermediate electrode 31 and the drain bus line 26 (B portion in FIG. 1A) is made narrower than the interval between the drain bus line 26 and the source electrode 42 (A portion in FIG. 1A). A current path is formed between the low-resistance intermediate electrode 31 formed of the same material as the drain electrode 42 and the source electrode 43 and the drain bus line 26, and the high-resistance gate insulating film 40 interposed between them or the protection The insulating film 46 is electrostatically destroyed (B portion in FIG. 1A).
[0043]
Thus, by providing a structure such as the A part and B part of FIG. 1A, that is, having a function like a so-called lightning rod, it is possible to prevent the TFT element 32 from being electrostatically destroyed. . Thereby, it is possible to prevent display defects from occurring in the liquid crystal display panel.
[0044]
In the present embodiment, since static electricity generated in the display portion is discharged in the display portion, display defects can be prevented more reliably than in the case of discharging outside the display portion.
[0045]
(Second Embodiment)
FIG. 2 is a partial plan view showing the TFT substrate of the liquid crystal display panel according to the active matrix display device of the second embodiment of the present invention. The second embodiment is different from the first embodiment in that a convex portion is provided on the drain bus line side in order to narrow the distance between the drain bus line and the source electrode of the TFT element. However, the description of the same elements as those in FIG. 1 is omitted.
[0046]
As shown in FIG. 2, the TFT substrate 10 a according to the active matrix display device of the second embodiment has a part of the drain bus line 26 in a portion where the drain bus line 26 and the source electrode 43 of the TFT element 32 face each other. The convex part 26a is formed in the area | region (D part of FIG. 2). 2 is narrower than the distance between the drain electrode 42 and the source electrode 43 of the TFT element 32, as in the first embodiment.
[0047]
Also in the second embodiment, the same effects as in the first embodiment can be obtained. In addition to this, there are the following effects. When the gate insulating film 40 or the protective insulating film 46 in the D part of FIG. 2 is electrostatically destroyed, a part of the drain bus line 26 and the source electrode 43 formed on the region is blown off.
[0048]
For this reason, when the drain bus line 26 is formed relatively thin in order to increase the aperture ratio of the liquid crystal display panel, the drain bus line 26 may be disconnected. In this embodiment, since the drain bus line 26 where the electrostatic breakdown is generated is thickened, it is possible to prevent the drain bus line 26 from being disconnected even if a part of the drain bus line 26 is blown off due to the electrostatic breakdown. Can do.
[0049]
In combination with the first embodiment, convex portions are formed on both the drain bus line 26 and the source electrode 43, and the distance between them is larger than the distance between the drain electrode 42 and the source electrode 43 of the TFT element 32. You may make it narrow.
[0050]
(Third embodiment)
3 and 4 are partial plan views showing a TFT substrate of a liquid crystal display panel according to an active matrix display device of a third embodiment of the present invention. The third embodiment is different from the first embodiment in that either or both of the drain bus line and the source electrode are pointed at a portion where the drain bus line and the source electrode of the TFT element face each other. 3 and FIG. 4, the description of the same elements as those in FIG. 1 is omitted.
[0051]
As shown in FIGS. 3 and 4, the TFT substrates 10 b and 10 c of this embodiment are provided with a convex portion on the drain bus line 26 side in a portion where the drain bus line 26 and the source electrode 43 of the TFT element 32 face each other. And the tip is sharpened. In the form shown in FIG. 3, a convex portion 26b having a pointed lower end is formed on the drain bus line 26 (E portion in FIG. 3). In the form shown in FIG. 4, the drain bus line 26 is formed with a convex portion 26c having a pointed central portion (F portion in FIG. 4).
[0052]
By sharpening the tip of the convex portion in this way, the charge density at the tip increases, so that a current accompanying discharge due to static electricity easily flows between the drain bus line 26 and the source electrode 43. That is, unlike the first and second embodiments, the distance between the drain bus line 26 and the source electrode 43 (E portion in FIG. 3 and F portion in FIG. 4) is set to the drain electrode 42 and the source electrode of the TFT element 32. Even if it is not narrower than the distance from 43, a discharge occurs between the drain bus line 26 and the source electrode 43, and it is possible to prevent the TFT element 32 from being electrostatically destroyed.
[0053]
Therefore, the distance between the drain bus line 26 and the source electrode 43 can be equal to or greater than the distance between the drain electrode 42 and the source electrode 43, so that the drain bus line 26 and the source electrode 42 are short-circuited. Can be prevented.
[0054]
In the present embodiment, the drain bus run 26 is provided with a convex portion at the portion where the drain bus line 26 and the source electrode 43 face each other, and the tip thereof is pointed. A convex portion may be provided on 43 and the tip thereof may be similarly sharpened, or a convex portion may be provided on both the drain bus line 26 and the source electrode 43 and the tip thereof may be sharpened.
[0055]
(Fourth embodiment)
FIG. 5 is a partial plan view showing a TFT substrate of a liquid crystal display panel according to an active matrix display device of a fourth embodiment of the present invention. The fourth embodiment is different from the first embodiment in that the distance between the drain bus line and the pixel electrode is narrower than the distance between the drain electrode and the source electrode of the TFT element. However, the description of the same elements as those in FIG. 1 is omitted.
[0056]
As shown in FIG. 5, in the TFT substrate 10d of this embodiment, a convex portion 28a is formed on a part of the side surface of the pixel electrode 28 on the drain bus line 26 side (G portion in FIG. 5). The distance between the front end surface of the projection 28 a of the pixel electrode 28 and the drain bus line 26 is made smaller than the distance between the drain electrode 42 and the source electrode 43 of the TFT element 32. Therefore, a discharge current path is formed between the pixel electrode 28 and the drain bus line 26 due to static electricity, and electrostatic breakdown occurs in the high-resistance protective insulating film 46, so that the TFT element 32 is electrostatically destroyed. Can be prevented.
[0057]
Further, in the present embodiment, the drain bus line 26 and the pixel electrode 28 are not formed by patterning the same metal film, but the lower layer is interposed via a protective insulating film 46 (see FIG. 1B). Since it is formed in the upper layer, there is no risk of short circuit even if the drain bus line 26 and the pixel electrode are brought close to each other.
[0058]
Instead of forming the convex portion 28 a on the drain bus line 26 side of the pixel electrode 28, a convex portion may be formed on the pixel electrode 28 side of the drain bus line 26. Further, recesses may be formed in both the pixel electrode 28 and the drain bus line 26. Furthermore, as in the third embodiment, the tip of the convex portion formed on one or both of the pixel electrode 28 and the drain bus line 26 may be pointed.
[0059]
(Fifth embodiment)
FIG. 6 is a partial plan view showing a TFT substrate of a liquid crystal display panel according to an active matrix display device of a fifth embodiment of the present invention. In the fifth embodiment, for example, two TFT elements are formed in one pixel region, and one is a dummy (pseudo) TFT element in which the interval between the drain electrode and the source electrode is narrowed. In the case of electrostatic breakdown, the dummy TFT element is intentionally electrostatically destroyed to protect the regular TFT element. In FIG. 6, the same elements as those in FIG.
[0060]
As shown in FIG. 6, on the TFT substrate 10e of this embodiment, regular TFT elements 32 and dummy TFT elements 32a formed according to a desired design rule are formed in one pixel region. The two TFT elements 32 and 32 a have a common drain electrode 42, and the drain electrode 42 is connected to the drain bus line 26.
[0061]
The source electrode 43 of the regular TFT element 32 is connected to the pixel electrode 28 through a contact hole 48 formed in the protective insulating film 46 (see FIG. 1B). On the other hand, in the dummy TFT element 32 a, the source electrode 43 a is connected to the pixel electrode 28 through a contact hole 48 a formed in the protective insulating film 46. The distance between the drain electrode 42 and the source electrode 43a of the dummy TFT element 32a is narrower than the distance between the drain electrode 42 and the source electrode of the regular TFT element 32. For this reason, discharge due to static electricity occurs between the drain electrode 42 and the source electrode 43a of the dummy TFT element 32a, so that the normal TFT element 32 can be prevented from being electrostatically destroyed.
[0062]
After the dummy TFT element 32a is electrostatically destroyed, the portion between the drain electrode 42 of the dummy TFT element 32a and the drain electrode 42 of the normal TFT element 32 may be cut and repaired using a laser or the like. it can. As a result, it is possible to prevent display defects from occurring in the liquid crystal display panel due to electrostatic breakdown of the regular TFT elements 32 due to discharge due to static electricity.
[0063]
In addition, it is important to recognize in advance which of the two TFT elements 32 and 32a is the dummy TFT element 32a, that is, which is the TFT element having the narrower distance between the drain electrode 42 and the source electrode 43. It is. That is, unlike the present embodiment, in the regular TFT element 32 and the dummy TFT element 32a, when the distance between the drain electrode 42 and the source electrode 43 is equal, which TFT element causes discharge due to static electricity? Since it is not known, it is difficult to repair by cutting with a laser or the like accurately when the TFT substrate is assembled into a liquid crystal display panel.
[0064]
However, in this embodiment, it is determined which of the two TFT elements is a dummy TFT element, and if the TFT element is recognized, the TFT substrate can be obtained even when the TFT substrate is assembled into a liquid crystal display panel. The drain electrode 42 of the dummy TFT element 32a can be repaired by cutting with a laser or the like from the back surface of the TFT.
[0065]
The details of the present invention have been described above by the first to fifth embodiments. However, the scope of the present invention is not limited to the examples specifically shown in the above embodiments, and does not depart from the present invention. Changes in the above embodiment within the scope of the gist are included in the scope of the present invention.
[0066]
For example, in the first to fifth embodiments, the TFT substrate according to the active matrix type liquid crystal display panel is exemplified, but the present invention can be similarly applied to an active matrix type organic EL display using TFT elements.
[0067]
(Additional remark 1) In the active matrix display device provided with the nonlinear element for every pixel, it connected to either the source electrode of the said nonlinear element, the electrically conductive film connected to the said source electrode, and the drain electrode of the said nonlinear element Protrusions are provided on at least one of the source electrode, the conductive film, and the drain bus line so that the distance to the drain bus line is narrower than the distance between the drain electrode and the source electrode of the nonlinear element. An active matrix display device.
[0068]
(Supplementary note 2) The active matrix display device according to supplementary note 1, wherein the conductive film connected to the source electrode is a pixel electrode or an intermediate electrode connected to the pixel electrode.
[0069]
(Additional remark 3) The said convex part is provided in the said source electrode or the said electrically conductive film, and the width | variety of the said drain bus line of the part facing the front-end | tip part of the said convex part is thicker than the width | variety of the said drain bus line of another place. The active matrix display device according to appendix 1 or 2, wherein
[0070]
(Additional remark 4) The active matrix display device as described in any one of additional remark 1 thru | or 3 with which the front-end | tip part of the said convex part has a sharp shape.
[0071]
(Supplementary Note 5) Each pixel has a plurality of TFT elements each having a drain electrode connected to the same drain bus line and a source electrode connected to the same pixel electrode, and a drain is provided between the TFT elements. An active matrix display device characterized in that an interval between an electrode and a source electrode is different.
[0072]
(Supplementary note 6) The supplementary note 5 is characterized in that the plurality of TFT elements include a regular TFT element and a pseudo TFT element in which a distance between the drain electrode and the source electrode is narrower than that of the regular TFT element. The active matrix display device described.
[0073]
(Supplementary note 7) In an active matrix display device including a non-linear element for each pixel, either the source electrode of the non-linear element or a conductive film connected to the source electrode, or the drain electrode of the non-linear element An active matrix display device, wherein a convex portion having a pointed end is provided on at least one of the source electrode, the conductive film, and the drain bus line at a portion adjacent to a drain bus line.
[0074]
(Supplementary Note 8) An interval between any one of the source electrode of the nonlinear element and the conductive film connected to the source electrode and a drain bus line connected to the drain electrode of the nonlinear element is equal to the gap of the nonlinear element. The active matrix display device according to appendix 7, wherein the distance between the drain electrode and the source electrode is equal to or greater than the distance between the drain electrode and the source electrode.
[0075]
【The invention's effect】
As described above, according to the present invention, the distance between the source electrode of the nonlinear element and the conductive film connected to the source electrode and the drain bus line connected to the drain electrode of the nonlinear element is A convex portion is provided on at least one of the source electrode, the conductive film, and the drain bus line so as to be narrower than an interval between the drain electrode and the source electrode of the nonlinear element.
[0076]
As a result, even if a current flows through the TFT substrate due to static electricity, a current path is formed between the data bus line and the conductive electrode connected to the source electrode of the TFT element or the source electrode, and between the data bus line and the source electrode. The high-resistance protective insulating film interposed in the substrate is electrostatically destroyed.
[0077]
Therefore, even if a current flows through the TFT substrate due to static electricity, there is no possibility that the TFT element will be destroyed, so that display defects due to static electricity can be prevented from occurring.
[Brief description of the drawings]
1A is a partial plan view showing a TFT substrate of a liquid crystal display panel according to an active matrix display device of a first embodiment of the present invention, and FIG. 1B is a plan view of FIG. It is a fragmentary sectional view in alignment with II.
FIG. 2 is a partial plan view showing a TFT substrate of a liquid crystal display panel according to an active matrix display device of a second embodiment of the present invention.
FIG. 3 is a partial plan view showing a TFT substrate of a liquid crystal display panel according to an active matrix display device of a third embodiment of the present invention (No. 1).
FIG. 4 is a partial plan view showing a TFT substrate of a liquid crystal display panel according to an active matrix display device of a third embodiment of the present invention (part 2).
FIG. 5 is a partial plan view showing a TFT substrate of a liquid crystal display panel according to an active matrix display device of a fourth embodiment of the present invention.
FIG. 6 is a partial plan view showing a TFT substrate of a liquid crystal display panel according to an active matrix display device of a fifth embodiment of the present invention.
FIG. 7 is a schematic configuration diagram showing a configuration of a general liquid crystal display panel.
FIG. 8 is a plan view showing an example of circuit elements formed on a TFT substrate of a liquid crystal display panel.
9A is an enlarged plan view of one pixel region in FIG. 8, and FIG. 9B is a cross-sectional view taken along line II-II in FIG. 9A.
[Explanation of symbols]
10-10d ... TFT substrate
24 ... Gate bus line
26 ... Drain bus line
28: Pixel electrode
26a-26c, 28a ... convex part
30 ... Storage capacity bus line
31 ... Intermediate electrode
32 ... TFT element
32a ... Dummy TFT element
36 ... Glass substrate
40 ... Gate insulating film
41 ... Amorphous silicon layer
42 ... Drain electrode
43 ... Source electrode
44 ... Channel protective film
46 ... Protective insulating film
48, 48a ... contact hole

Claims (5)

In an active matrix display device having a non-linear element for each pixel,
The distance between one of the source electrode of the nonlinear element and the conductive film connected to the source electrode and the drain bus line connected to the drain electrode of the nonlinear element is such that the drain electrode and the source of the nonlinear element are An active matrix display device, wherein a projection is provided on at least one of the source electrode, the conductive film, and the drain bus line so as to be narrower than a distance from the electrode. The active matrix display device according to claim 1, wherein the conductive film connected to the source electrode is a pixel electrode or an intermediate electrode connected to the pixel electrode. The convex portion is provided on the source electrode or the conductive film, and the width of the drain bus line at the portion facing the tip of the convex portion is wider than the width of the drain bus line at another location. The active matrix display device according to claim 1 or 2. In an active matrix display device having a non-linear element for each pixel,
The source electrode, the conductive film, and the conductive film connected to the source electrode of the nonlinear element and the drain bus line connected to the drain electrode of the nonlinear element are adjacent to each other. An active matrix display device, wherein at least one of the drain bus lines is provided with a convex portion having a sharp tip. Each pixel has a plurality of TFT elements each having a drain electrode connected to the same drain bus line and a source electrode connected to the same pixel electrode, and the drain electrode and the source electrode are arranged between the plurality of TFT elements. The active matrix display device is characterized in that the interval between and is different.

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