TWI404181B - Pixel array substrate and liquid crystal display - Google Patents

Abstract

A pixel array substrate including at least one contact hole structure comprising a patterned metal layer, an insulating layer and a patterned semiconductor layer is provided. The patterned metal layer comprises at least one contact region, wherein the contact region has a first width w1 in a direction. The insulating layer is disposed on the patterned metal layer and has at least one contact hole exposing a portion of the contact region. An angle between a top surface and a bottom surface of the insulating layer is &thgr; , a thickness of the insulating layer is d, a width of the contact hole in mentioned direction is w2, and (3d/tan&thgr;+w2) ≤ w1 ≤ (6d/tan&thgr;+w2). The patterned semiconductor layer is disposed on the insulating layer and covered the contact hole to contact with the contact region of the patterned metal layer.

Description

Pixel array substrate and liquid crystal display device

The present invention relates to a pixel array substrate and a liquid crystal display device, and more particularly to a pixel array substrate having a contact window structure and a liquid crystal display device having the above pixel array substrate.

In the 3C era of life, there are a variety of information devices on the market, such as mobile phones, digital cameras, digital cameras, notebook computers, and desktop computers, all of which are oriented toward more convenient, versatile and beautiful directions. development of. In most information devices, the flat display device is used as the main communication interface, and the display function of the flat display device makes the user's operation more convenient. Among them, the liquid crystal display device has become the mainstream of the market due to its advantages of power saving, high image quality, good space utilization efficiency, low power consumption, and no radiation.

In general, a liquid crystal display device includes a pixel array substrate, a counter substrate, and a liquid crystal layer between the two substrates. The pixel array substrate includes a patterned metal layer, a protective layer, and a pixel electrode layer sequentially stacked on the substrate. In the above structure, a parasitic capacitance may be generated between the patterned metal layer and the pixel electrode layer, thereby causing a crosstalk phenomenon and seriously affecting the display quality of the liquid crystal display device. In order to reduce the coupling capacitance between the patterned metal layer and the pixel electrode layer, a conventional solution is to add an insulating layer having a low dielectric constant between the protective layer and the pixel electrode layer to enhance the liquid crystal display. The display quality of the device. Wherein, after the insulating layer and the protective layer are formed, a portion of the insulating layer and a portion of the protective layer are removed to form a contact opening, such that the pixel electrode layer is electrically connected to a contact region (eg, a drain) in the patterned metal layer. .

1 is a schematic cross-sectional view of a conventional contact window structure. The contact window structure 100 includes a contact region 110, a protective layer 120, an insulating layer 130, and a pixel electrode 140. It is to be noted that the insulating layer 130 generally has a thickness of several micrometers, and thus the top surface 130a and the bottom surface 130b of the insulating layer 130 may have an angle θ at the edge of the contact window opening 130c. In this way, the tilting direction of the liquid crystal molecules (not shown) located at the edge is not in an ideal state, and there is no contact region 110 under the edge to block the light, so that the liquid crystal display has a dark state light leakage phenomenon, which will This causes a contrast value of the liquid crystal display device and a deterioration in display quality. A conventional solution is to increase the size of the contact zone 110 to a considerable extent to block light leakage at the edges of the contact opening 130c by the contact zone 110. However, when the oversized contact region 110 is located in the visible region, the aperture ratio of the liquid crystal display device is drastically lowered.

The present invention provides a pixel array substrate having a contact window structure capable of reducing a dark state light leakage phenomenon and having a high aperture ratio.

The present invention further provides a liquid crystal display device having a contact window structure capable of reducing a dark state light leakage phenomenon and having a high aperture ratio, thereby having a better display quality.

The invention provides a pixel array substrate having at least one contact window structure, wherein the contact window structure comprises a patterned metal layer, an insulating layer and a patterned conductor layer. The patterned metal layer has at least one contact region, wherein the contact region has a first width w1 in one direction. The insulating layer is disposed on the patterned metal layer and has at least one contact window opening exposing a partial region of the contact region, wherein an angle between a top surface and a bottom surface of the insulating layer at an edge of the contact window opening is θ, a thickness of the insulating layer Is d, wherein the contact opening has a second width w2 in the aforementioned direction, and (3d/tan θ + w2) ≦ w1 ≦ (6d / tan θ + w2). The patterned conductor layer is disposed on the insulating layer and covers the contact opening of the contact window to contact the patterned metal layer.

The present invention further provides a liquid crystal display device comprising a pixel array substrate, a pair of substrates, and a liquid crystal layer disposed between the pixel array substrate and the opposite substrate. The pixel array substrate has at least one contact window structure, wherein the contact window structure comprises a patterned metal layer, an insulating layer and a patterned conductor layer. The patterned metal layer has at least one contact region, wherein the contact region has a first width w1 in one direction. The insulating layer is disposed on the patterned metal layer and has at least one contact window opening exposing a partial region of the contact region, wherein an angle between a top surface and a bottom surface of the insulating layer at an edge of the contact window opening is θ, a thickness of the insulating layer Is d, wherein the contact opening has a second width w2 in the aforementioned direction, and (3d/tan θ + w2) ≦ w1 ≦ (6d / tan θ + w2). The patterned conductor layer is disposed on the insulating layer and covers the contact opening of the contact window to contact the patterned metal layer.

In an embodiment of the invention, the material of the insulating layer comprises a perfluoroalkyl vinyl ether copolymer (PFA).

In an embodiment of the invention, the contact zone comprises a drain.

In an embodiment of the invention, the patterned conductor layer comprises a plurality of pixel electrodes.

In an embodiment of the invention, the contact window structure further includes a protective layer between the patterned metal layer and the insulating layer.

In an embodiment of the invention, the material of the protective layer comprises tantalum nitride.

In an embodiment of the invention, the insulating layer and the patterned metal layer have a translation error m in the above direction, and (3d/tan θ + w2 + 2m) ≦ w1 ≦ (6d / tan θ + w2 + 2m).

In one embodiment of the invention, the translational error m is less than or equal to 6 microns.

In an embodiment of the invention, the liquid crystal display device further includes a backlight module, wherein the pixel array substrate, the opposite substrate and the liquid crystal layer are disposed above the backlight module.

In summary, the pixel array substrate has a contact window structure capable of reducing dark light leakage, and the contact window structure can minimize the influence on the aperture ratio of the pixel array substrate. Therefore, the liquid crystal display device using such a pixel array substrate has better contrast values and display quality.

The above described features and advantages of the present invention will be more apparent from the following description.

2A is a partial top plan view of a pixel array substrate according to an embodiment of the invention. Fig. 2B is a schematic cross-sectional view taken along line A-A' of Fig. 2A. Referring to FIG. 2A and FIG. 2B simultaneously, the present embodiment only shows one pixel area in the pixel array substrate 200 as a representative. In fact, the pixel array substrate 200 should include a plurality of pixel areas. The pixel array substrate 200 has at least one contact window structure 220. The contact window structure 220 includes a patterned metal layer 222, an insulating layer 224, and a patterned conductor layer 226. The patterned metal layer 222 has at least one contact region 222a, wherein the contact region 222a has a first width w1 in a direction D. The insulating layer 224 is disposed on the patterned metal layer 222 and has at least one contact opening 224a exposing a partial region of the contact region 222a. The top surface 224b of the insulating layer 224 and the bottom surface 224c are at an angle θ at the edge of the contact opening 224a, and the thickness of the insulating layer 224 is d, wherein the contact opening 224a has a second width w2 in the direction D, and 3d/tan θ + w2) ≦ w1 ≦ (6d / tan θ + w2). The patterned conductor layer 226 is disposed on the insulating layer 224 and covers the contact opening 224a to contact the patterned metal layer 222. The patterned conductor layer 226 of this embodiment is exemplified by an element constituting a pixel electrode.

2A and 2B, the pixel array substrate 200 includes a plurality of arrays of active elements 212 disposed on the substrate 202 as switches, and only one active element 212 is shown. The active device 212 includes a gate 212g stacked on the substrate 202, a gate insulating layer 214, a channel layer 212c, and a source 212s and a drain 212d. Each active element 212 is connected to a scan wiring SL and a data wiring DL corresponding thereto.

In the present embodiment, the patterned metal layer 222 includes a data wiring DL and a source 212s and a drain 212d. Contact area 222a is, for example, a drain. In another embodiment, the patterned metal layer includes a gate and a scan line. Therefore, the contact area is not limited to being a bungee.

2A and 2B, in the present embodiment, the insulating layer 224 is disposed on the patterned metal layer 222 and has a contact opening 224a exposing a partial region of the drain 212d. The material of the insulating layer 224 is, for example, PerFluoro Alkoxyethylene (PFA). In order to reduce the coupling capacitance between the patterned conductor layer 226 and the patterned metal layer 222, the thickness d of the insulating layer 224 is, for example, 3 micrometers. Therefore, the top surface 224b and the bottom surface 224c of the insulating layer 224 may have an included angle θ at the edge of the contact window opening 224a, for example, 39°.

In the present embodiment, the contact window structure 220 further includes a protective layer 223 between the patterned metal layer 222 and the insulating layer 224. The material of the protective layer 223 is, for example, tantalum nitride. In other words, the contact window structure 220 includes the patterned metal layer 222, the protective layer 223, the insulating layer 224, and the patterned conductor layer 226 which are sequentially stacked. Moreover, in another embodiment, the contact window structure further includes a gate insulating layer disposed between the patterned metal layer and the insulating layer.

2A and 2B, in the present embodiment, the patterned conductor layer 226 constitutes a plurality of pixel electrodes, and only one pixel electrode is shown here. The patterned conductor layer 226 is disposed on the insulating layer 224 and fills the contact opening 224a to be electrically connected to the drain 212d. The material of the patterned conductor layer 226 may be indium tin oxide (ITO), indium zinc oxide (IZO), zinc aluminum oxide (AZO) or other transparent conductor material.

2A and 2B, in the present embodiment, the first width w1 of the contact region 222a in the direction D is, for example, between the range of 26.1 micrometers and 37.2 micrometers. The thickness d of the insulating layer 224 is, for example, 3 μm, and the angle θ between the top surface 224b and the bottom surface 224c of the insulating layer 224 at the edge of the contact opening 224a is, for example, 39°. The second width w2 of the contact window opening 224a in the direction D is, for example, 15 microns. Among them, (3d/tan θ + w2) ≦ w1 ≦ (6d / tan θ + w2).

It is worth mentioning that in the process of fabricating the contact window structure 220, the main process parameters are the thickness d of the insulating layer 224 and the angle θ between the top surface 224b and the bottom surface 224c at the edge of the contact window opening 224a. Therefore, after determining the second width w2 of the contact window opening 224a, a contact region having an appropriate size (ie, the first width w1) can be designed according to (3d/tan θ + w2) ≦ w1 ≦ (6d / tan θ + w2) 222a. In this way, the dark state light leakage caused by the small size of the contact region 222a can be effectively reduced, and the problem of the pixel aperture loss caused by the excessive size of the contact region 222a can be avoided.

In practice, in the process of fabricating the contact window structure 220, between the insulating layer 224 and the patterned metal layer 222, there may be a translation error in the horizontal direction, and the component of the translation error in the direction D is m (not shown). ). At this time, (3d/tan θ + w 2+ 2 m) ≦ w1 ≦ (6d / tan θ + w 2+ 2 m). In an embodiment, the translation error m is less than or equal to 6 microns.

3 is a partial top plan view of a pixel array substrate according to another embodiment of the invention. Referring to FIG. 3, the present invention does not limit the number of pixel electrodes in the patterned conductor layer 226. Therefore, in the pixel array substrate 200', the patterned conductor layer 226 may include a first pixel electrode 226a and a second pixel electrode 226b, wherein the first pixel electrode 226a substantially surrounds the second pixel electrode 226b and The two pixel electrodes 226b are separated.

4 is a cross-sectional view showing a liquid crystal display device according to still another embodiment of the present invention. Referring to FIG. 4 , the liquid crystal display device 300 includes a pixel array substrate 310 , an opposite substrate 320 , and a liquid crystal layer 330 disposed between the pixel array substrate 310 and the opposite substrate 320 . The pixel array substrate 310 may be one of the pixel array substrates 200, 200' as illustrated in FIG. 2A or FIG. 3, and similar structures are not repeated herein. Furthermore, a plurality of color filter films (not shown) may be disposed on the pixel array substrate 310. Alternatively, the color filter film may be disposed on the opposite substrate 320. In addition, if the liquid crystal display device 300 adopts a transmissive or transflective design, a backlight module 340 may be further included to provide a surface light source. The pixel array substrate 310, the opposite substrate 320, and the liquid crystal layer 330 are disposed above the backlight module 340, and are displayed by using the light provided by the backlight module 340.

In the present embodiment, the structure of the pixel array substrate 310 is similar to that of the pixel array substrate 200. Referring to FIG. 2B and FIG. 4 simultaneously, since the top surface 224b and the bottom surface 224c of the insulating layer 224 have an included angle θ at the edge of the contact window opening 224a. Therefore, the liquid crystal molecules located in the vicinity of the contact opening 224a may be tilted with the contour at the edge, so that the tilting direction of the liquid crystal molecules does not conform to the ideal state, causing the liquid crystal display device 300 to have a dark state light leakage phenomenon. However, in the present embodiment, the contact region 222a can block light from the backlight module 340. Therefore, the phenomenon of the dark state light leakage can be reduced. Further, since the size of the contact region 222a is designed, the aperture ratio of the pixel array substrate 310 is not greatly affected, so that the contrast value of the liquid crystal display device 300 can be improved. Display quality.

In summary, the liquid crystal display device using the pixel array substrate of the present invention can improve the dark light leakage caused by the contact window structure without significantly affecting the aperture ratio of the pixel, thereby improving the liquid crystal. The contrast value of the display device and the display quality. Further, the pixel array substrate of the present invention and the method of fabricating the liquid crystal display device are compatible with the existing processes, and do not cause a substantial increase in production cost. Moreover, since the appropriate size of the contact area can be estimated, the production cost can be effectively saved to increase the process capacity.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100. . . Contact window structure

110. . . Contact area

120. . . The protective layer

130. . . Insulation

130a. . . Top surface

130b. . . Bottom

130c. . . Contact window opening

140. . . Pixel electrode

200, 200', 300. . . Pixel array substrate

202. . . Substrate

212. . . Active component

212c. . . Channel layer

212d. . . Bungee

212g. . . Gate

212s. . . Source

214. . . Brake insulation

220. . . Contact window structure

222. . . Patterned metal layer

222a. . . Contact area

223. . . The protective layer

224. . . Insulation

224a. . . Contact window opening

224b. . . Top surface

224c. . . Bottom

226. . . Patterned conductor layer

226a, 226b. . . Pixel electrode

300. . . Liquid crystal display device

320. . . Counter substrate

330. . . Liquid crystal layer

340. . . Backlight module

d. . . thickness

θ. . . Angle

W1. . . First width

W2. . . Second width

D. . . direction

DL. . . Data wiring

SL. . . Scanning wiring

1 is a schematic cross-sectional view of a conventional contact window structure.

2A is a partial top plan view of a pixel array substrate according to an embodiment of the invention.

Fig. 2B is a schematic cross-sectional view taken along line A-A' of Fig. 2A.

3 is a partial top plan view of a pixel array substrate according to another embodiment of the invention.

4 is a cross-sectional view showing a liquid crystal display device according to still another embodiment of the present invention.

200. . . Pixel array substrate

202. . . Substrate

212d. . . Bungee

214. . . Brake insulation

220. . . Contact window structure

222. . . Patterned metal layer

222a. . . Contact area

223. . . The protective layer

224. . . Insulation

224a. . . Contact window opening

224b. . . Top surface

224c. . . Bottom

226. . . Pixel electrode layer

d. . . thickness

θ. . . Angle

W1. . . First width

W2. . . Second width

D. . . direction

Claims (17)

A pixel array substrate having at least one contact window structure, wherein the contact window structure comprises: a patterned metal layer having at least one contact region, wherein the contact region has a first width w1 in one direction; an insulating layer, Arranging on the patterned metal layer and having at least one contact window opening exposing a partial region of the contact region, an angle between a top surface and a bottom surface of the insulating layer at an edge of the contact window opening is θ, the insulation The thickness of the layer is d, wherein the contact opening has a second width w2 in the direction, and (3d/tan θ + w2) ≦ w1 ≦ (6d / tan θ + w2); and a patterned conductor layer disposed thereon And contacting the contact opening on the insulating layer to contact the contact area. The pixel array substrate of claim 1, wherein the material of the insulating layer comprises a perfluoroalkyl vinyl ether copolymer. The pixel array substrate of claim 1, wherein the contact region comprises a drain. The pixel array substrate of claim 1, wherein the patterned conductor layer comprises a plurality of pixel electrodes. The pixel array substrate of claim 1, wherein the contact window structure further comprises a protective layer between the patterned metal layer and the insulating layer. The pixel array substrate of claim 5, wherein the material of the protective layer comprises tantalum nitride. The pixel array substrate of claim 1, wherein the insulating layer and the patterned metal layer have a translation error m in the direction, and (3d/tan θ+w2+2m) ≦w1 ≦ (6d/tan θ+w2+2m) . The pixel array substrate of claim 7, wherein the translation error m is less than or equal to 6 micrometers. A liquid crystal display device comprising: a pixel array substrate having at least one contact window structure, wherein the contact window structure comprises: a patterned metal layer having at least one contact region, wherein the contact region has a first direction in a direction a width w1; an insulating layer disposed on the patterned metal layer and having at least one contact opening exposing a portion of the contact region, a top surface and a bottom surface of the insulating layer being at an edge of the contact opening The angle of the insulating layer is θ, and the thickness of the insulating layer is d, wherein the contact opening has a second width w2 in the direction, and (3d/tan θ + w2) ≦ w1 ≦ (6d / tan θ + w2); a conductor layer disposed on the insulating layer and covering the contact opening to contact the patterned metal layer; a pair of substrates; and a liquid crystal layer disposed between the pixel array substrate and the opposite substrate. The liquid crystal display device of claim 9, wherein the material of the insulating layer comprises a perfluoroalkyl vinyl ether copolymer. The liquid crystal display device of claim 9, wherein the contact region comprises a drain. The liquid crystal display device of claim 9, wherein the patterned conductor layer comprises a plurality of pixel electrodes. The liquid crystal display device of claim 9, wherein the contact window structure further comprises a protective layer between the patterned metal layer and the insulating layer. The liquid crystal display device of claim 13, wherein the material of the protective layer comprises tantalum nitride. The liquid crystal display device of claim 9, wherein the insulating layer and the patterned metal layer have a translation error m in the direction, and (3d/tan θ + w2 + 2m) ≦ w1 ≦ (6d / tan θ + w2 + 2m). The liquid crystal display device of claim 15, wherein the translation error m is less than or equal to 6 micrometers. The liquid crystal display device of claim 9, further comprising a backlight module, wherein the pixel array substrate, the opposite substrate and the liquid crystal layer are disposed above the backlight module.