Thin film transistor liquid crystal display

A thin film transistor (TFT) liquid crystal display (LCD) panel, its array substrate, and its manufacturing method. Color filters are integrated on the TFT array, and color filter stacks are formed on the thin film transistors to replace a black matrix, thereby reducing manufacturing time and costs. The color filter stacks can be placed at the border of the display area of the panel to reduce light leakage. The border of the display area has a liquid crystal injection hole. To allow the size of the liquid crystal injection hole to be increased, and to reduce the light leakage at the hole, color filter blocks and overlapping metal layers can be used at the border of the display area. The color filter stacks and other dielectric layers need to be away from the welding points of repair structures to prevent dielectric layer bursts during a repair process. Storage capacitors can use the feature described above so that the color filters are positioned away from the overlapping portions. Welding is used to improve the electrical contact between the metal layers and the pixel electrode.

BACKGROUND

This invention relates to a liquid crystal display panel, and more particularly to a thin film transistor liquid crystal display having color filters integrated with a thin film transistor array (referred to as color filter on array, abbreviated as COA), its array substrate, and its fabrication method.

With the advancement of technology, video products, particularly digital video or image devices, have become common products in everyday lives. In these digital video or image devices, display devices are important components that allow users to obtain information or to further control the operation of the video or image devices.

The sizes of video or image devices have become thinner and lighter. While traditional cathode ray tube (CRT) displays have certain advantages, they take up considerable space and consume more energy. Using optoelectronics and semiconductor manufacturing technologies, flat panel displays, such as thin film transistor (TFT) liquid crystal displays (LCDs), have become popular display products. TFT LCDs have several advantages over traditional CRT displays, such as lower operation voltage, zero radiation, light weight, and smaller volume. TFT LCDs and other flat panel displays, such as plasma displays and electroluminance displays, recently have become a main topic of display researches, and have been viewed as the mainstream display devices of the twenty-first century.

FIG. 1shows a conventional TFT LCD panel, which typically has a TFT array substrate102, an opposite substrate104, and a liquid crystal layer (not shown), which is positioned between the substrates102and104. On the TFT array substrate102, there is a TFT array112, which includes scan lines, data lines, and thin film transistors. Between the substrates102and104, there is a frame sealant106that is used to seal the space between the substrates102and104so that the liquid crystal remains within the sealed space. The sealed space is mainly used to display patterns or colors, and thus is referred to as the display area. The frame sealant106has a liquid crystal injection hole108to facilitate injection of the liquid crystal.

In addition to the conventional TFT LCD panel described above, there is another kind of technique for manufacturing TFT LCD panels, characterized in that color filters (which are thin films) are fabricated directly on the substrate102that has the TFT array112. An advantage of this technique is that the aperture ratio can be increased. The TFT LCD panels that have color filters integrated on the TFT array substrate can be used in products such as thin and light-weight notebooks having high definition displays, LCD televisions, and high-end LCD monitors.

The conventional TFT LCD panel having color filters integrated with the TFT array substrate can have a number of disadvantages.

In the example ofFIG. 1, prior to fabricating the color filters directly on the substrate104that has the TFT array112, it is necessary to fabricate the black matrix (BM) first. Many researches have focused on finding ways to reduce the cost and manufacturing time of TFT LCD panels that use the color-filter-on-array technique. When the black matrix and the color filters are fabricated on different substrates, misalignment of the back matrix and the color filters may reduce the product yield rate.

Light emitted by circuitry on the substrate102can be leaked from the border110(FIG. 1) of the display area, adversely affecting the display quality of the TFT LCD panel. Light can also be leaked from the liquid crystal injection hole108.

Each TFT in the TFT array112, or the conducting lines surrounding the TFT array112, typically has a repair structure (not shown) that can be used to repair defects in the TFT or defects in the signal lines (line defects). In a conventional design, the repair structure is covered by a thick layer of dielectric. Bursts often occur in the dielectric layer during the repair process, preventing the defective TFT or signal line from being repaired.

Each TFT in the TFT array112corresponds to a storage capacitor (Cst) that is formed by an insulation layer sandwiched between two metal layers. The upper metal layer is connected to a pixel electrode so that it can be controlled by the TFT. Because of imperfections in the microlithography process, such as imperfections in the development of photoresist or etching process, portions of the dielectric layer may remain between the metal layer and the pixel electrode due to incomplete exposure or incomplete etching, resulting in poor electric contact between the metal layer and the pixel electrode. Such imperfections prevent the storage capacitor from maintaining a specified charge within a specified time to allow the display pixel to show a specified gray level, thus reducing the performance of the display panel.

SUMMARY OF THE INVENTION

An object of the invention is to provide a TFT LCD panel and its fabrication method to reduce the fabrication time.

Another object of the invention is to provide a TFT LCD panel and its fabrication method to reduce the fabrication cost.

Another object of the invention is to provide a TFT LCD panel and its fabrication method to reduce the amount of light that is leaked at the border of the display area.

Another object of the invention is to provide a TFT LCD panel and its fabrication method to reduce the amount of light leaked at the LCD injection hole.

Another object of the invention is to provide a TFT LCD panel and its fabrication method to prevent dielectric layer bursts from occurring at the repair structures during repair processes.

Another object of the invention is to provide a TFT LCD panel and its fabrication method to prevent the problem of poor electric connectivity at the storage capacitor.

This invention provides a TFT array substrate that includes a substrate, scan lines, data lines, TFTs, pixel electrodes, color filters, and color filter stacks. The scan lines and the data lines are disposed on the substrate and define pixel regions. The TFTs are disposed at the intersections of scan lines and data lines, and are controlled by using the scan lines and the data lines. The pixel electrodes are disposed in the pixel regions and connected to corresponding TFTs. The color filters are disposed on the pixel regions, and the color filter stacks are disposed on the color filters.

A TFT LCD panel can be fabricated by adding an opposite substrate and a liquid crystal layer that is sandwiched between the substrates.

According to one aspect of the invention, a TFT pixel structure is provided in which pixel regions are disposed above the substrate. The pixel regions include pixel electrodes, TFTs, signal lines, first color filter stacks, second color filter stacks, and third color filter stacks. The pixel electrodes and the TFTs are disposed in the pixel regions. Signal lines are disposed at the borders of the pixel regions to define the pixel regions. Pixel electrodes are electrically connected to the signal lines through the TFTs. The first color filter stacks are disposed on the pixel electrodes, the second color filter stacks are disposed on the signal lines, and the third color filter stacks are disposed on the TFTs.

According to another aspect of the invention, a TFT array substrate fabrication method includes forming a first metal layer on a substrate, and patterning the first metal layer to form gate electrodes and scan lines. A gate insulation layer is formed above the substrate, and a patterned amorphous silicon layer is formed above the gate electrode to form channel layers. A second metal layer is formed above the substrate and patterned to form source electrodes and drain electrodes above the gate electrodes, and data lines above the substrate. The data lines and the scan lines define pixel regions. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes form TFTs. First color filters are formed in the pixel regions, and second color filters are formed above the first color filters above the TFTs. Pixel electrodes are formed above the substrate in the pixel regions, and the pixel electrodes are electrically connected to corresponding TFTs.

An opposing substrate can be positioned at a distance from the TFT array substrate. A TFT LCD panel can be fabricated by forming a liquid crystal layer between the TFT array substrate and the opposing substrate.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes forming scan lines on a substrate, and forming data lines on the substrate, wherein the data lines and the scan lines define pixel regions. TFTs are formed at the intersections of the scan lines and the data lines, and are controlled by using the data lines and the scan lines. Pixel electrodes are formed in the pixel regions and electrically connected to corresponding TFTs. Color filters are formed above the pixel regions, and color filter stacks are formed on the color filters above the TFTs.

According to another aspect of the invention, a TFT array substrate includes a display area and a non-display area, characterized in that a ring-shaped color filter stack is disposed in the non-display area and surrounds the display area.

According to another aspect of the invention, a TFT array substrate includes a display area and a non-display area, characterized in that first metal layers are disposed in the non-display area at the border of the display area, and second metal layers partially overlap the first metal layers to prevent light from leaking at the border of the display area.

According to another aspect of the invention, a TFT array substrate includes a display area and a non-display area, characterized in that a first metal layer is disposed at the border of the display area, a second metal layer partially overlaps the first metal layer, and at least a ring-shaped color filter surrounds the display area.

According to another aspect of the invention, a light shielding structure, suitable for use in a non-display area of a TFT array substrate, includes a first metal layer that is disposed at a non-display area, a second metal layer that overlaps the first metal layer, in which the first and second metal layers are electrically insulated by an insulation layer, and at least one color filter is disposed above the first and second metal layers.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes forming a first metal layer above a substrate that includes a display area and a non-display area. A first metal layer is patterned to form gate electrodes and scan lines, in which the scan lines extend to the border of the display area. A gate insulation layer and an amorphous silicon layer are formed above the substrate. Portions of the amorphous layer that are not directly above the gate electrode are removed to form channel layers. A second metal layer is formed above the substrate and patterned to form source electrodes and drain electrodes above the gate electrodes, to form data lines above the substrate, and to form strips of quasi-metal layers at the border of the display area. The data lines and the scan lines define of pixel regions. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes in combination form TFTs, and the quasi-metal layers partially overlap the scan lines. A first color filter is formed above the substrate. The first color filter is patterned to preserve portions of the first color filter that are in the pixel regions and at the border of the display area. A second color filter is formed to overlap the first color filter at the border of the display area. Pixel electrodes are formed in the pixel regions above the substrate, and the pixel electrodes are electrically connected to corresponding TFTs.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes providing a substrate that includes a display area and a non-display area, characterized in that a ring-shaped color filter stack is formed in the non-display area of the substrate, in which the ring-shaped color filter stack surrounds the border of the display area.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes forming a first metal layer above a substrate, the substrate including a display area and a non-display area. The first metal layer is patterned to form gate electrodes and scan lines in the display area, in which the scan lines extend to the border of the display area. A gate insulation layer is formed above the substrate, and an amorphous layer is formed and patterned to form channel layers above the gate electrodes. A second metal layer is formed above the substrate and patterned to form source electrodes and drain electrodes above the gate electrodes, to form data lines above the substrate, and to form strips quasi-metal layers at the border of the display area, in which the data lines and the scan lines define pixel regions. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes form TFTs. The quasi-metal layers partially overlap the scan lines to prevent light from leaking at the border of the display area. Color filters are formed in the pixel regions above the substrate. Pixel electrodes are formed in the display area above the substrate, in which the pixel electrodes are electrically connected to corresponding TFTs.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes forming a first metal layer above a substrate that includes a display area and a non-display area. The first metal layer is patterned to form gate electrodes and scan lines in the display area, and to form strips quasi-metal layers at the border of the display area. A gate insulation layer is formed above the substrate, and a patterned amorphous silicon layer is formed above the gate electrode to form channel layers. A second metal layer is formed above the substrate and patterned to form source electrodes and drain electrodes above the gate electrodes, to form data lines above the substrate, in which the data lines extend to the border of the display area, and the data lines and the scan lines define pixel regions. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes together form TFTs, and the quasi-metal layers partially overlap the data lines to prevent light from leaking at the border of the display area. Color filters are formed in the pixel regions above the substrate. Pixel electrodes are formed in the display area above the substrate, in which the pixel electrodes are electrically connected to corresponding TFTs.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes providing a substrate that includes a display area and a non-display area, characterized in that first metal layers are formed at the borders of the display area, and second metal layers are formed above the substrate, the second metal layers partially overlapping the first metal layers to prevent light from leaking at the border of the display area.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes forming a first metal layer above a substrate that includes a display area and a non-display area. The first metal layer is patterned to form gate electrodes and scan lines in the display area, the scan lines extending to the border of the display area. A gate insulation layer is formed above the substrate. A patterned amorphous silicon layer is formed above the gate electrode to form channel layers. A second metal layer is formed above the substrate and patterned to form source electrodes and drain electrodes above the gate electrodes, to form data lines above the substrate, and to form strips quasi-metal layers at the border of the display area. The data lines and the scan lines define pixel regions. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes together form TFTs, and the quasi-metal layers partly overlap the scan lines to prevent light from leaking at the border of the display area. A first color filter is formed above the substrate. The first color filter is patterned to preserve portions of the first color filter in the pixel region, and to form a ring-shaped color filter at the border of the display area. Pixel electrodes are formed in the display area above the substrate, in which the pixel electrodes are electrically connected to corresponding TFTs.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes forming a first metal layer above a substrate that includes a display area and a non-display area. The first metal layer is patterned to form gate electrodes and scan lines in the display area, and to form strips of quasi-metal layers at the border of the display area. A gate insulation layer is formed above the substrate. A patterned amorphous silicon layer is formed above the gate electrodes to form channel layers. A second metal layer is formed above the substrate and patterned to form source electrodes and drain electrodes above the gate electrodes, to form data lines above the substrate, in which the data lines extend to the border of the display area. The data lines and the scan lines define pixel regions. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes together form TFTs, and the quasi-metal layers partially overlap the data lines to prevent light from leaking at the border of the display area. A first color filter is formed above the substrate. The first color filter is patterned to preserve portions of the first color filter in the pixel region, and to form a ring-shaped color filter at the border of the display area. Pixel electrodes are formed in the display area above the substrate, in which the pixel electrodes are electrically connected to corresponding TFTs.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes providing a substrate that includes a display area and a non-display area, characterized in that first metal layers are formed at the border of the display area, and second metal layers are formed above the substrate, wherein the second metal layers partially overlap the first metal layers. A ring-shaped color filter is formed to surround the border of the display area.

According to another aspect of the invention, a TFT array substrate includes a display area and a non-display area, the non-display area having a liquid crystal injection hole, characterized in that the TFT array substrate has first metal layers that are disposed at the non-display area, and second metal layers that partially overlap the first metal layers. A color filter stack is disposed in the non-display area outside of the liquid crystal injection hole. A first color filter block is positioned above the portion of the non-display area exposed by the liquid crystal injection hole.

According to another aspect of the invention, a TFT array substrate includes a display area and a non-display area, in which the border of the non-display area has a liquid crystal injection hole. First metal layers are disposed at the portion of the substrate exposed by the liquid crystal injection hole. Second metal layers partially overlap the first metal layers to prevent light from leaking at the liquid crystal injection hole.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes forming a first metal layer above a substrate that includes a display area and a non-display area, in which the border of the display area has a liquid crystal injection hole. The first metal layer is patterned to form gate electrodes and scan lines, in which the scan lines extend to the border of the display area. A gate insulation layer and an amorphous silicon layer are formed above the substrate. Portions of the amorphous layer that are not directly above the gate electrodes are removed to form channel layers. A second metal layer is formed above the substrate and patterned to form source electrodes and drain electrodes above the gate electrodes, to form data lines above the substrate, and to form strips of quasi-metal layers. The data lines and the scan lines define pixel regions. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes together form thin film transistors. The quasi-metal layers partially overlap the scan lines. A first color filter is formed above the substrate and patterned to preserve portions of the first color filter that are in the pixel regions and at the portion of the substrate exposed by the liquid crystal injection hole at the border of the display area. Pixel electrodes are formed in the display area above the substrate and electrically connected to corresponding TFTs.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes forming a first metal layer above a substrate that includes a display area and a non-display area, in which the border of the display area has a liquid crystal injection hole. The first metal layer is patterned to form gate electrodes and scan lines in the display area, and to form strips of quasi-metal layers above the substrate that is exposed by the opening of the liquid crystal injection hole at the border of the display area. A gate insulation layer is formed above the substrate. A patterned amorphous layer is formed above the gate electrode to generate channel layers. A second metal layer is formed above the substrate and patterned to form a source electrodes and drain electrodes above the gate electrodes, to form data lines above the substrate that extend to the liquid crystal injection hole at the border of the display area. The data lines and the scan lines define pixel regions. The quasi-metal layers partially overlap the data lines to prevent light from leaking through the opening at the liquid crystal injection hole. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes in combination form thin film transistors. Color filters are formed in the pixel regions. Pixel electrodes are formed in the pixel regions and electrically connected to corresponding TFTs.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes providing a substrate that includes a display area and a non-display area, in which the non-display area has a liquid crystal injection hole. First metal layers are formed at the border of the display area. Second metal layer are formed above the substrate, in which the second metal layers partially overlap the first metal layers to prevent light from leaking through the liquid crystal injection hole at the border of the display area.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes forming a first metal layer above a substrate that includes a display area and a non-display area, in which the border of the display area has a liquid crystal injection hole. The first metal layer is patterned to form gate electrodes and scan lines in the display area, and to form a quasi-metal layer above the substrate that is exposed by the opening of the liquid crystal injection hole. A gate insulation layer and an amorphous silicon layer is formed above the substrate. Portions of the amorphous silicon layer that are not directly above the gate electrodes are removed to form channel layers. A second metal layer is formed above the substrate and patterned to form source electrodes and drain electrodes above the gate electrodes, to form data lines above the substrate that extend to the liquid crystal injection hole. The data lines and the scan lines define pixel regions. The quasi-metal layer partially overlap the scan lines. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes in combination form thin film transistors. A first color filter is formed above the substrate and patterned to preserve portions of the first color filter in the pixel region. A first color filter block is formed above the portion of the substrate that is exposed by the liquid crystal injection hole. Pixel electrodes are formed in the pixel region and electrically connected to corresponding TFTs.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes providing a substrate that includes a display area and a non-display area, in which the border of the non-display area has a liquid crystal injection hole, characterized in that first metal layers are formed at the border of the display area, second metal layers are formed above the substrate, in which the second metal layers partially overlap the first metal layers. A first color filter block is formed above the portion of the substrate that is exposed by the liquid crystal injection hole.

According to another aspect of the invention, a TFT array substrate includes repair structures that includes a first metal layer, a second metal layer, an insulation layer, a channel layer, a dielectric layer, a transparent electrode layer, and at least one color filter. The first metal layer is disposed on a substrate that includes scan lines, gate electrodes, first repair metal layers. The insulation layer covers the first metal layer. The channel layer is disposed on the insulation layer above the gate electrode. The second metal layer is disposed above the substrate, and includes the source electrodes, the drain electrodes, the data lines, and the second repair metal layers. The source electrodes and the drain electrodes are disposed above the gate electrodes and are at the two sides of the channel layers. The data lines and the scan lines define pixel regions. The second repair metal layers and the first repair metal layers overlap each other to form the repair structures. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes in combination form TFTs. The dielectric layer is disposed above the first metal layer, the insulation layer, and the second metal layer. The dielectric layer has repair openings and contact windows. The repair openings expose the second repair metal layers of the repair structures. The contact windows expose the source electrodes of the TFTs. The transparent electrodes are disposed above the dielectric layer, and includes pixel electrodes and floating electrodes. The pixel electrodes are disposed in the pixel regions and are electrically connected to the source electrodes of the corresponding TFTs through the contact windows. The floating electrodes are electrically connected to the second repair metal layers through the repair openings. The color filters are disposed in the pixel region away from the repair openings. A TFT LCD panel can be formed by adding an opposite substrate, and adding a liquid crystal layer between the two substrates.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes forming a first metal layer on a substrate, patterning the first metal layer to form scan lines, gate electrodes, and first repair metal layers. A gate insulation layer and an amorphous layer are formed above the substrate, and the portions of the amorphous layer that are not directly above the gate electrodes are removed to form channel layers. A second metal layer is formed above the substrate, in which the second metal layer is patterned to form source electrodes, drain electrodes, data lines, and second repair metal layers. The source electrodes and the drain electrodes are disposed above the gate electrodes and are at the two sides of the channel layers. The data lines and the scan lines define pixel regions. The second repair metal layers overlap the first repair metal layers to form the repair structures. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes in combination form thin film transistors. A dielectric layer is formed above the first metal layer, the insulation layer, and the second metal layer, wherein the dielectric layer includes repair openings and contact windows. The repair openings expose the second repair metal layers of the repair structures, and the contact windows expose the source electrodes of the thin film transistors. First color filters are formed in the pixel regions away from the repair openings. Second color filters are formed, covering portions of the first color filters above the substrate. A transparent electrode is formed above the substrate, the transparent electrode including pixel electrodes and floating electrodes. The pixel electrodes are electrically connected to the source electrodes of corresponding thin film transistors through the contact windows, and the floating electrodes are electrically connected to the second repair metal layers through the repair openings.

A TFT LCD panel can be formed by providing an opposite substrate that is spaced apart from the TFT array substrate, and forming a liquid crystal layer between the TFT array substrate and the opposite substrate.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes forming a first metal layer on a substrate, the first metal layer including scan lines, gate electrodes, and first repair metal layers. An insulation layer is formed above the substrate covering the first metal layer, and channel layers are formed on the insulation layer above the gate electrodes. A second metal layer is formed above the substrate, the second metal layer including source electrodes, drain electrodes, data lines, and second repair metal layers. The source electrodes and the drain electrodes are disposed above the gate electrodes and are at the two sides of the channel layers. The data lines and the scan lines define pixel regions. The second repair metal layers overlap the first repair metal layers to form the repair structures. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes form thin film transistors. A dielectric layer is formed above the first metal layer, the insulation layer, and the second metal layer, wherein the dielectric layer includes repair openings and contact windows. The repair openings expose the second repair metal layers of the repair structures, and the contact windows expose the source electrodes of the thin film transistors. Pixel electrodes are formed in the pixel regions, wherein the pixel electrodes are electrically connected to the source electrodes of corresponding thin film transistors through the contact windows. At least one color filter is formed above the pixel regions outside of the repair openings.

According to another aspect of the invention, a TFT array substrate having storage capacitors includes a first metal layer, a second metal layer, an insulation layer, a channel layer, a dielectric layer, pixel electrodes, and color filters. The first metal layer is disposed on a substrate, the first metal layer including scan lines, gate electrodes, and first storage capacitor metal layers, in which the first storage capacitor metal layers have first openings. The insulation layer covers the first metal layer. The channel layers are disposed on the insulation layer above the gate electrodes. A second metal layer is disposed above the substrate, the second metal layer including source electrodes, drain electrodes, data lines, and second storage capacitor metal layers. The source electrodes and the drain electrodes are disposed above the gate electrodes and at the two sides of the channel layers. The data lines and the scan lines define pixel regions. The second storage capacitor metal layers overlap the first storage capacitor metal layers, and the first and second storage capacitors and the insulation layer form storage capacitors. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes form thin film transistors. A dielectric layer is disposed above the first metal layer, the insulation layer, and the second metal layer, wherein the dielectric layer has second openings and third openings. The second openings approximately expose the second storage capacitor metal layers above the first openings, and the third openings expose the source electrodes of the thin film transistors. Pixel electrodes are disposed in the pixel regions. The pixel electrodes are electrically connected to the second storage capacitor layers through the second openings, and are electrically connected to the source electrodes of corresponding thin film transistors through the third openings. Color filters are disposed on the pixel regions outside of the second openings.

Further, a TFT LCD panel can be formed by providing an opposite substrate and forming a liquid crystal layer between the two substrates.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes forming a first metal layer on a substrate, patterning the first metal layer to form scan lines, gate electrodes, and first storage capacitor metal layers, the first storage capacitor metal layers having first openings. An insulation layer is formed above the substrate, and a patterned amorphous silicon layer is formed above the gate electrodes to form channel layers. A second metal layer is formed above the substrate, and the second metal layer is patterned to form source electrodes, drain electrodes, data lines, and second storage capacitor metal layers. The source electrodes and the drain electrodes are disposed above the gate electrodes and at the two sides of the channel layers. The data lines and the scan lines define pixel regions. The second storage capacitor metal layers overlap the first storage capacitor metal layers. The first storage capacitor metal layers, the second storage capacitor metal layers, and the insulation layers in combination form storage capacitors. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes form thin film transistors. A dielectric layer is formed above the first metal layer, the insulation layer, and the second metal layer, wherein the dielectric layer has second openings and third openings. The second openings approximately expose the second storage capacitor metal layers above the first openings, and the third openings expose the source electrodes of the thin film transistors. Color filters are formed in the pixel regions outside of the second openings. Pixel electrodes are formed above the substrate. The pixel electrodes are electrically connected to the second storage capacitor layers through the second openings, and electrically connected to the source electrodes of corresponding thin film transistors through the third openings.

Further, a TFT LCD panel can be formed by providing an opposite substrate that is spaced apart from the TFT array substrate and forming a liquid crystal layer between the TFT array substrate and the opposite substrate.

According to another aspect of the invention, a method of fabricating a TFT array substrate includes forming a first metal layer on a substrate, the first metal layer including scan lines, gate electrodes, and first storage capacitor metal layers, in which the first storage capacitor metal layers have first openings. An insulation layer is formed above the substrate to cover the first metal layer, and channel layers are formed on the insulation layer above the substrate. A second metal layer is formed above the substrate, the second metal layer including source electrodes, drain electrodes, data lines, and second storage capacitor metal layers. The source electrodes and the drain electrodes are disposed above the gate electrodes and at the two sides of the channel layers. The data lines and the scan lines define pixel regions. The second storage capacitor metal layers overlap the first storage capacitor metal layers. The first storage capacitor metal layers, the second storage capacitor metal layers, and the insulation layers form storage capacitors. The gate electrodes, the channel layers, the source electrodes, and the drain electrodes form thin film transistors. A dielectric layer is formed above the first metal layer, the insulation layer, and the second metal layer, wherein the dielectric layer has second openings and third openings. The second openings approximately expose the second storage capacitor metal layers above the first openings, and the third openings expose the source electrodes of the thin film transistors. Pixel electrodes are formed in the pixel regions. The pixel electrodes are electrically connected to the second storage capacitor layers through the second openings, and are electrically connected to the source electrodes of corresponding thin film transistors through the third openings. Color filters are formed in the pixel regions outside of the second openings.

According to the present invention, color filter stacks are formed above the thin film transistors to replace a black matrix, so fabrication time and cost can be reduced.

The TFT array substrate according to the present invention can use color filter stacks and partially overlapping metal layers at the border of a display area to achieve good light shielding effects.

The TFT array substrate according to the present invention uses partially overlapping metal layers and color filter blocks at a liquid crystal injection hole of a display area, so good light shielding effects can be achieved, and the size of the liquid crystal injection hole can be increased.

According to the present invention, only a passivation layer covers the welding point of the repair structure of the TFT array substrate, so dielectric layer bursts (which may occur in a prior art structures due to the presence of a dielectric layer at the welding point) will not occur during the repair process.

The TFT array substrate of the present invention has integrated color filters and has storage capacitors having welding points similar to those used for repair structures. The electrical connection between the storage capacitor metal layer and the pixel electrode is improved, thus increasing the effectiveness of the LCD panel. Because the first metal layer is positioned away from the opening used for the welding point, short-circuiting of the first and second metal layers during the welding process can be prevented.

The present invention uses color filter stacks to replace the black matrix, so fabrication time and cost can be reduced. Improvements have been made in the structure and the fabrication process, responsive to particular requirements of different parts of the LCD panel, and taking into account the basic manufacturing process flow, allowing fabrication time and cost of the LCD panel to be reduced.

The following description and accompanying figures provide examples of preferred embodiments to allow easy understanding of the objects, characteristics, and advantages of the invention.

DESCRIPTION

This invention relates to providing different designs for different portions of a TFT array substrate having integrated color filters, referred to as color filter on array (COA), to meet the requirements of various fabrication processes or applications. Fabrication of a black matrix can be omitted. The following embodiments are used as examples to describe the various applications of the present invention.

THE FIRST EMBODIMENT

FIG. 2shows a schematic diagram of a TFT LCD panel according to the present invention.

Referring toFIG. 2, a TFT LCD panel200according to the present invention includes a TFT array substrate202, an opposite substrate204, and a liquid crystal layer (not shown) that is positioned between the substrates202and204. On the TFT array substrate202, there are scan lines210, data lines212, thin film transistors216, pixel electrodes218, color filters (not referenced with labels), and color filter stacks220. The data lines212and the scan lines210define pixel regions214. Thin film transistors216are disposed at the intersections of data lines212and scan lines210, and are controlled by using the data lines212and the scan lines210. Pixel electrodes218are disposed in the pixel regions214and are connected to corresponding thin film transistors216.

The color filters (not shown) are disposed above the pixel region214, in which the color filters include red filters, green filters, and blue filters (the filters are in the form of thin films). The color filter stacks220are disposed on the color filters above the TFT216. When the color filter is of a first color, the color filter stack220can be, for example, overlapping color filters of a second color and a third color, or can be a single color filter of the second color, or a single color filter of the third color. When the color filter stack220is formed by overlapping color filters of the second and third colors, the color filter that is closer to the TFT216is thicker than the color filter that is farther away from the TFT216.

Because the blue filter has a higher absorption rate than the red and green filters, when only one color filter is used, it would be better to use a blue filter.FIGS. 3A to 3Dshow the fabrication process for the present embodiment.

FIGS. 3A to 3Ddepict cross-sectional process views showing a method of fabricating a TFT array substrate according to the first embodiment of the present invention. Referring toFIGS. 2 and 3A, a first metal layer is formed on the substrate202. The first metal layer is patterned to form gate electrodes302and scan lines210(FIG. 2). A gate insulation layer304and an amorphous silicon layer are formed above the substrate202. The portions of the amorphous silicon layer that is not directly above the gate electrode are removed, forming channel layers306(there is one channel layer, the plural term “channel layers” refers to multiple portions of the channel layer). A second metal layer is formed above the substrate202. The second metal layer is patterned to form source electrodes and drain electrodes308above the gate electrodes302, and to form data lines212(FIG. 2) above the substrate300. The data lines and the scan lines define pixel regions214(FIG. 2). The gate electrodes302, the channel layers306, the source electrodes, and the drain electrodes308in combination form thin film transistors216.

Referring toFIGS. 2 and 3B, a passivation layer312is formed above the thin film transistor216. A first color filter314is formed in the pixel region214(hereafter, the term “first color filter” refers to a color filter that allows a first color to pass). A color filter stack220is formed above the first color filter314, which is above the TFT216. The color filter stack220includes a second color filter316and a third color filter318(hereafter, the terms “second color filter” and “third color filter” refer to color filters that allow a second color and a third color, respectively, to pass). The color filter314shown at the right portion ofFIG. 3Bis part of the color filter for the pixel that includes the TFT216. The second color filter316shown at the left portion ofFIG. 3Bis part of the color filter for another pixel. Portions of the adjacent color filters314and316overlap at the data line212and the scan line210.

Referring toFIG. 3C, a dielectric layer322is formed above the substrate202and covers the entire substrate202. As an example, the dielectric layer322can be made of acrylic acid. A pixel electrode218is formed above the dielectric layer322and is electrically connected to the drain electrode308of the thin film transistor216.

FIG. 3Dshows a cross-sectional view of the TFT LCD display panel that includes an opposite substrate204, which is spaced apart from the TFT array substrate202(FIG. 3C). The opposite substrate204includes a common electrode222. A liquid crystal layer340is formed between the opposite substrate204and the TFT array substrate202. Prior to forming the liquid crystal layer340, a photo spacer326can be formed above the dielectric layer322to maintain a predefined cell gap. An orientation layer (not shown) can be positioned between the TFT array substrate202and the liquid crystal layer340. Another orientation layer (not shown) can be positioned between the opposite substrate204and the liquid crystal layer340. In addition, a polarizer (not shown) can be disposed at each of the outer surface of the TFT array substrate202and the outer surface of the upper substrate204.

FIGS. 3D and 4depicts the structure of the current embodiment.FIG. 4shows a top view of the TFT array substrate according to the first embodiment of the invention.

Referring toFIGS. 3D and 4, a color filter stack220according to the present invention is positioned above the TFT216, in which the second and third color filters316and318are stacked one over the other above the first color filter314. The first color filter314is the color filter for the pixel region214(FIG. 2), and has an opening400to expose the pixel electrode218and the electrical contact portion of the drain electrode308of the TFT216. A second or third color filter316or318covers another side of the pixel structure, and its borders can overlap the first color filter314. The second or third color filter316or318can be the color filter of another pixel region.

THE SECOND EMBODIMENT

This embodiment improves the border of the display area of the TFT LCD panel. Referring toFIG. 2, a display area500refers to the region that includes pixel regions214and can display patterns and colors. The regions outside of the display area500are referred to as the non-display area.

FIGS. 5A to 5Cdepict cross-sectional process views showing a method of fabricating a TFT LCD panel according to a second embodiment of the present invention. The differences between the first and second embodiments are as follows.

Referring toFIG. 5A, the first metal layer is formed above the substrate202. The first metal layer is patterned to generate the structure shown inFIG. 3Aand a first metal layer502at the border of the display area500. A gate insulation layer304is formed above the substrate202, and is used for insulation. A second metal layer is formed above the substrate. The second metal layer is patterned to form the structure shown inFIG. 3Aand another metal layer506at the border of the display area500. The metal layers502and506are adjacent to each other, preferably partially overlapping each other (as shown inFIG. 5D) to prevent light from leaking at the border of the display area500.

When the metal layer502is used for external connection lines, the metal layer502is connected to scan line210, and the metal layer506acts as a “quasi-metal layer” for forming dummy lines. Conversely, when the metal layer506is used for external connection lines, the metal layer506is connected to the data line212, and the metal layer502serves as a quasi-metal layer. Metal layers502and506can simultaneously act as quasi-metal layers and not connect to the scan line210or the data line212. By positioning the metal layers502and506adjacent to each other, or partially overlapping each other (as shown inFIG. 5D), light directed towards the non-display area can be shielded, preventing light leakage.

Referring toFIG. 5B, a passivation layer312is formed above the substrate202. Optionally, at least one color filter can be formed above the substrate at the border of the display area500to enhance the light shielding effect. In the example shown inFIG. 5B, a color filter stack220is formed above a first color filter314above the TFT216(FIG. 2). The color filter stack220can also be a single layer of the second color filter or the third color filter.

Referring toFIG. 5C, a dielectric layer322is formed above the substrate202, covering the color filter stack220. A frame sealant522, such as a frame sealant that has ball spacers, is formed on the substrate202. The opposite substrate204is provided and glued to the TFT array substrate.

Please note that in the present embodiment, although the color filter stack220and the adjacent or partially overlapping metal layers502and506are formed above the substrate202, as shown inFIGS. 5A and 5D, all that is required is to form a structure that can shield light at the border of the display area500of the TFT array substrate. In one example, during the fabrication process described above, the fabrication of the color filter stack220can be omitted, and only the adjacent or partially overlapping metal layers502and506are formed. In another example, the adjacent or partially overlapping metal layers502and506are omitted, and only the color filter stack220is formed.

FIGS. 5C and 6depict the structure of the present embodiment.FIG. 6shows a top view of the border of the display area of the TFT LCD panel according to the second embodiment.

Referring toFIGS. 5C and 6, the color filter stack220of the present embodiment is positioned at the border of the display area500, and the metal layers502and506are positioned between the color filter stack220and the substrate202. The metal layers502and506are electrically insulated from each other, and are adjacent to or partially overlap each other to prevent light leakage. The structure according to the present embodiment can be chosen to have only one color filter stack220at the border of the display area500, or to have only adjacent or partially overlapping metal layers502and506at the border of the display area500. Light shielding effects can be achieved by either having only the color filter stack220, only the adjacent or partially overlapping metal layers502and506, or both.

THE THIRD EMBODIMENT

This embodiment mainly relates to improving the liquid crystal injection hole at the border of the display area of the TFT LCD panel. Referring toFIG. 2, the liquid crystal injection hole700is positioned at the border of the display area500. Liquid crystal can be injected from this hole.

FIGS. 7A and 7Bdepict cross-sectional process views showing a method of fabricating a TFT LCD panel according to a third embodiment of the present invention. The third embodiment is similar to the second embodiment, except for the steps after forming the adjacent or partially overlapping metal layers502and506. Referring toFIG. 7A, to facilitate injection of the liquid crystal, the liquid crystal injection hole700is made to have a larger diameter. Multiple color filter blocks can be formed on the portion of the substrate202that is exposed by the liquid crystal injection hole700to enhance the light shielding effect. For example, in these figures, three color filter blocks314,316, and318are formed adjacent to each other at the position where the liquid crystal injection hole is located. These three color filter blocks are formed at the same time as when the color filter314and the color filter stack220of the second embodiment are formed.

Referring toFIG. 7B, a dielectric layer322is formed above the substrate202, in which the dielectric layer322covers the color filter blocks314,316, and318. The remaining fabrication steps are similar to those of the second embodiment. In the third embodiment, although the color filter blocks314,316, and318, and the adjacent or partially overlapping metal layers502and506are formed above the substrate, it is also possible to use other structures that have light shielding effects.

FIGS. 7B and 8shows a structure of this embodiment, in whichFIG. 8shows a top view of the TFT array substrate where the liquid crystal injection hole is located. Referring toFIGS. 7B and 8, a larger space is reserved between the TFT array substrate202and the opposite substrate204for the liquid crystal injection hole700(FIG. 2) to facilitate injection of liquid crystal. The difference between the third embodiment and the second embodiment is that, in the third embodiment, the color filters are formed as blocks that are adjacent to each other to allow the height of the color filters to be lowered, so that the distance between the dielectric layer322and the substrate202meets the requirements for liquid crystal injection.

The TFT LCD panel according to the third embodiment can selectively use the adjacent or partially overlapping metal layers502and506, without using the color filters314,316, and318, and still achieve the light shielding effect and prevent light leakage.

THE FOURTH EMBODIMENT

This embodiment is mainly relates to improvement in the repair structure of the TFT array substrate.

FIGS. 9A to 9Care cross-sectional process views showing a method of fabricating the TFT array substrate according to a fourth embodiment of the present invention, which can be used with the fabrication process of the first embodiment.

Referring toFIG. 9A, a first metal layer is formed and patterned on the substrate202to form first repair metal layers902(there is one first repair metal layer, the plural term “first repair metal layers” refers to multiple portions of the first metal layer) in addition to the structure shown inFIG. 3A. Afterwards, the processing steps are similar to the processing steps of the first embodiment. An insulation layer304is formed above the substrate202. A second metal layer is formed and patterned on the substrate202to form second repair metal layers906(there is one second repair metal layer, the plural term “second repair metal layers” refers to multiple portions of the second repair metal layer) in addition to the structure shown inFIG. 3A. The second repair metal layer906and the first repair metal layer902in combination form a repair structure. The repair metal layers902and906can be adjacent to each other or have portions that overlap, and are positioned within the pixel region214(FIG. 2).

Referring toFIG. 9B, a passivation layer312is formed above the substrate202, covering the second repair metal layer906and the insulation layer304. A color filter314and a color filter stack220(which is positioned above the color filter314) can be formed in portions of the pixel region that are not directly above the second repair metal layer906. For example, the color filter stack220according to the first embodiment is formed above the TFT216. A dielectric layer322is formed above the substrate202, covering the entire substrate202.

Referring toFIG. 9C, a dielectric layer322and a passivation layer312are defined to form an opening910for the welding point of the repair structure, and to expose the second repair metal layer906.

Referring toFIG. 9D, a pixel electrode218is formed above the dielectric layer322. The pixel electrode218is electrically floated and disposed at the surface at the opening910to cover and protect the exposed second repair metal layer906. Layers other than the pixel electrode218can also be used as the passivation layer. Because the welding point (the opening910) of the repair structure according to the present invention is protected by only a pixel electrode, dielectric layer bursts (which may occur in prior art structures) will not occur during the repair process.

FIGS. 9D and 10show the structure of a TFT LCD panel according to the fourth embodiment, in whichFIG. 10is a top view of a repair structure for a TFT array substrate according to the fourth embodiment of the invention.

Referring toFIGS. 9D and 10, the difference between the structures of the first and fourth embodiments is that, in the fourth embodiment, there is only one pixel electrode218that serves as a protection layer covering the welding point (which is at the opening910) of the repair structure. The repair structure includes the first repair metal layer902and the second repair metal layer906. In addition, in the fourth embodiment, the color filter314and the color filter stack220are disposed at a location away from the welding point (which is at the opening910).

THE FIFTH EMBODIMENT

FIGS. 11A to 11Care cross-sectional process views showing a method of fabricating a storage capacitor of the TFT array substrate according to a fifth embodiment of the present invention. The fifth embodiment is similar to the fourth embodiment, wherein the difference between the fifth and fourth embodiments is that, the partially overlapping metal layers of the first metal layer that is formed and patterned above the substrate202has first storage capacitor metal layers1102(the plural term “first storage capacitor metal layers” refers to multiple portions of the first storage capacitor metal layer), as shown inFIG. 11A, in addition to the structure shown inFIG. 3A. The first storage capacitor metal layer1102has first openings1103, and the first storage capacitor metal layer1102can be a part of the scan line or a part of a common line. Afterwards, the processing steps are similar to those of the fourth embodiment. An insulation layer304is formed above the substrate202. A second metal layer is formed above the substrate202, and is patterned to have, in addition to the structure shown inFIG. 3A, second storage capacitor metal layers1106(the plural term “second storage capacitor metal layers” refers to multiple portions of the second storage capacitor metal layer). The second storage capacitor metal layer1106overlaps the insulation layer304, which overlaps the first storage capacitor metal layer1102. The second storage capacitor metal layer1106, the insulation layer304, and the first storage capacitor metal layer1102in combination form a storage capacitor.

Referring toFIG. 11B, a passivation layer312is formed above the substrate202, covering the second storage capacitor metal layer1106and the insulation layer304. A color filter314,316, or318is formed above the portions of the passivation layer312that is outside of the opening1103. A dielectric layer322is formed above the substrate202. Here, the color filter314,316, or318are used as the color filters of each pixel region.

Referring toFIG. 11C, the dielectric layer322and the passivation layer312are defined to form a second opening1110that serves as a contact window, and to expose the second storage capacitor metal layer1106that is above the first opening1103.

Referring toFIG. 11D, a pixel electrode218is formed above the dielectric layer322, and is electrically connected to the second storage capacitor metal layer1106through the second opening1110. After the pixel electrode218is formed, a welding process can proceed to weld the pixel electrode218(which is at the second opening1110) with the second storage capacitor metal layer1106. The first storage capacitor metal layer1102is positioned away from the second opening1110that serves as a contact window. When the pixel electrode218is welded to the second storage capacitor metal layer1102in order to fix poor electrical contacts, the short-circuiting of the first and second storage capacitor metal layers1102and1106can be avoided.

FIGS. 11D and 12show the structure of the fifth embodiment, in whichFIG. 12is a top view of a storage capacitor of the TFT array substrate according to the fifth embodiment of the present invention.

Referring toFIGS. 11D and 12, the fifth embodiment uses a welding point (which is the opening1110) similar to the welding point of the repair structure of the fourth embodiment, a welding process can be used to weld the pixel electrode218and the second storage capacitor metal layer1106to prevent poor electrical contact at their interface and to improve the storage capacitor's storage capability. Because the first storage capacitor metal layer1102is positioned away from the contact window formed by the opening1110, during the welding process, the problem of short-circuiting the first and second storage capacitor metal layers can be avoided.

The present invention includes the following features:

1. The TFT array substrate according to the present invention uses overlapping color filters to replace the black matrix, the yield rate of the TFT LCD panel can be improved due to reduced errors in the alignment of the TFT array substrate and the opposite substrate.

2. The TFT array substrate can have, color filter stacks and metal layers that contact or partially overlap each other, at the borders of the display area to achieve a good light shielding effect.

3. Partially connected or partially overlapping metal layers are used at the liquid crystal injection hole at the border of the display area of the TFT array substrate. Color filter blocks can also be used to effectively shield light and to increase the size of the liquid crystal injection hole.

4. The welding point of the repair structure of the TFT array substrate is only covered by a single passivation layer, thus dielectric layer bursts (which may occur in a prior art structure that has a dielectric layer above the welding point) can be prevented during the repair process.

5. The TFT array substrate, which has integrated color filters, has storage capacitors having welding points similar to those used for repair structures. This can prevent poor electrical contact between the metal layer and the pixel electrode, and increase the effectiveness of the storage capacity. Because the first metal layer is positioned away from the opening used as the contact window, short-circuiting of the first and second metal layers during a welding process can be prevented.

In the present invention, by using the color filter stacks to replace the black matrix, the fabrication time and cost can be greatly reduced. Responsive to special requirements of different parts of the LCD panel, this invention provides improvements in the structure and the fabrication process of the LCD panel to save time and effort.

Although the present invention has been described using the embodiments above, the invention should not be limited to those embodiments, and can be modified by a person skilled in the art in various manners without departing from the spirit and scope of the invention. The scope of the present invention should only be limited by the claims below.