CN1292301C - Liquid crystal display with uniform common voltage and manufacturing method thereof - Google Patents

Abstract

The invention provides a liquid crystal display with uniform common voltage and a manufacturing method thereof, which are used for providing excellent picture quality. The manufacturing method comprises the following steps: the method comprises the steps of firstly manufacturing a plurality of scanning lines, signal lines, common electrode leads and a plurality of common electrode pads on the surface of a lower substrate, electrically connecting the common electrode pads with the common electrode leads, then forming a plurality of photoresist spacers on the lower surface of an upper substrate, enabling each photoresist spacer to correspond to each common electrode pad of the lower substrate, then forming a conductive material layer on the lower surface of the upper substrate to cover each photoresist spacer, then combining the upper substrate and the lower substrate, electrically connecting the conductive material layer covered on each photoresist spacer with each common electrode pad corresponding to each photoresist spacer, and finally filling liquid crystal molecules between the two substrates for sealing, wherein the impedance of the material for forming the common electrode leads is smaller than that of the material for forming the conductive material layer.

Description

Liquid crystal display with uniform common voltage and manufacturing method thereof

technical field

The invention provides a liquid crystal display, especially a liquid crystal display with a uniform common voltage and a manufacturing method thereof.

Background technique

Due to the characteristics of light, thin, low power consumption and no radiation pollution, liquid crystal displays are widely used in portable information such as notebook computers (notebooks), personal digital assistants (PDAs), and video cameras (video cameras). In terms of products, there is even a tendency to gradually replace CRT monitors or TVs.

Most of the existing thin film transistor (TFT) liquid crystal displays use any spray method to insert plastic beads, glass beads or glass fibers to support the gap between the liquid crystal layers between the glass substrates ( cell gap), relatively and control the size of the gap to get a stable display quality. However, these inserted plastic beads may be located in the light penetration area, or present an uneven distribution, resulting in aggregation, causing light to be scattered by the plastic beads, etc., reducing the contrast intensity of TFT-LCD light, or producing white spots (white point) defects seriously affect the display quality and product pass rate. Therefore, the photoresist spacer (photospacer) formed by the development process has been developed to replace the existing plastic beads, so as to accurately control the size and position of the spacer, maintain a good gap size, and improve the picture quality. .

Please refer to FIG. 1 and FIG. 2 , FIG. 1 is a basic structure diagram of a conventional liquid crystal display panel 10 , and FIG. 2 is a schematic cross-sectional structure diagram of the liquid crystal display panel 10 in FIG. 1 . As shown in FIG. 1 , the liquid crystal display panel 10 can be divided into a display area 12 and a non-display area 14 surrounding the display area 12 . In the display area 12, a pixel matrix (including a plurality of pixels 20) formed by interlacing multiple rows of signal lines (data lines) 16 and multiple columns of scan lines (scan lines) 18, and a plurality of thin film transistors ( thinfilm transistor, TFT), capacitors and other electronic components (not shown in FIG. 1 ), which are arranged at the intersection of each row of signal lines 16 and each column of scan lines 18 . The non-display area 14 is used to set packaging test materials and signal transmission lines, including peripheral circuit components, repair lines, tape and reel package 26 and other structures, and a plurality of silver glue dots evenly distributed in the non-display area 14 . In terms of structure, the liquid crystal display panel 10 includes a lower substrate 22 , an upper substrate 24 and a plurality of liquid crystal molecules (not shown) filled between the lower substrate 22 and the upper substrate 24 . The upper surface of the lower substrate 22 includes signal lines 16 , scan lines 18 , a plurality of tape and reel packages 26 located in the non-display area 14 and a plurality of thin film transistors (not shown). Wherein, the signal lines 16 and the scanning lines 18 are respectively electrically connected to the corresponding tape and reel packages 26 for outputting signals to the lower substrate 22, so that the liquid crystal display panel 10 displays images, and the thin film transistors are respectively It is arranged at the intersection of each signal line 16 and each scanning line 18 as a switching element of a pixel. The lower substrate 22 further includes a plurality of pixel electrodes (pixel electrodes) 28 formed by a layer of transparent conductive material, electrically connected to each thin film transistor, and a layer of alignment film 30, covering the surface of the thin film transistor and the pixel electrodes 28, Used to control the alignment direction of liquid crystal molecules.

As shown in Figure 2, the underside surface of upper substrate 24 is provided with a plurality of black matrix layers (blackmatrix) 32, color filter (color filter) 34, one as the opposite electrode (counter electrode) 36 of liquid crystal display panel 10 a layer of transparent conductive material, and a plurality of photoresist spacers 38 . The color filter 34 includes three types: a red filter 34 a , a green filter 34 b and a blue filter 34 c , and each color filter 34 of three colors forms a group to form a pixel 20 . The black matrix layer 32 is disposed at the junction between each color filter 34 and the upper substrate 24 . The opposite electrode 36 completely covers the surface of the color filter 34 to provide the voltage required for the display to work. The photoresist spacer 38 is a transparent or opaque micro-column used to replace the plastic beads. According to the design of different manufacturers, the distribution density of the photoresist spacer 38 will be different. Generally, it can Supporting the gap of the liquid crystal layer and controlling the size of the gap are the main considerations, so that the photoresist spacers 38 are uniformly distributed throughout the liquid crystal display panel 10 . In the conventional liquid crystal display 10 process, after depositing the opposite electrode 36 on the lower surface of the upper substrate 24 , photoresist spacers 38 are formed on the surface of the opposite electrode 36 by exposing and developing. In addition, the lower surface of the upper substrate 24 may further include an alignment film (not shown) covering the surface of the opposite electrode 36 .

The driving method of the existing liquid crystal display 10 is to provide a stable common voltage value through the opposite electrode 36, and at the same time use the tape and reel package body 26 on the non-display area 14 to transmit the data signal to the signal line 16, and pass through each pixel The TFT 28 in 20 provides a pixel voltage to each pixel electrode 28 respectively according to the data signal, and finally uses the electric field formed by the common voltage and the pixel voltage to turn the liquid crystal molecules in the pixel, and Allows light to pass through the layer of liquid crystal material. The liquid crystal molecules are deflected to different degrees according to the different electric field strengths of each pixel, and affect the total amount of light transmitted through each pixel, thereby determining the display quality of the liquid crystal display 10 . Therefore, a stable pixel voltage or common voltage value is one of the keys for the liquid crystal display 10 to effectively present a complete picture.

In the prior art, the common voltage is provided by connecting to the lower substrate 22 through a circuit, and then transferring it to the opposite electrode 36 of the upper substrate 24 through a silver glue point, so that the entire liquid crystal display 10 has the same common voltage value. However, the constituent material of the opposite electrode 36 used in the existing liquid crystal display 10 is generally indium tin oxide (indium tin oxide, ITO), and its impedance is very large, about 90Ω/□, while the silver glue used for conducting the voltage value The dots are only distributed around the liquid crystal display 10, so when the common voltage is conducted to the opposite electrode 36 via the silver glue point, and then to the middle part of the liquid crystal display 10 via the edge portion of the opposite electrode 36, it will be due to the formation of the opposite electrode 36. The material such as indium tin oxide has a large resistance value, which causes a voltage drop, especially when the liquid crystal display 10 is a large-area display, the problem of the voltage drop will be more serious, resulting in uneven common voltage values of the upper substrate 24, and it is impossible to correctly control the liquid crystal display. The turning of the molecules makes it impossible to achieve the optimization of the picture. Therefore, providing a liquid crystal display with a uniform common voltage and a manufacturing method thereof to provide excellent image quality is a problem still to be solved in the industry.

Contents of the invention

Therefore, the main purpose of the present invention is to provide a liquid crystal display with a uniform common voltage and a manufacturing method thereof, so as to solve the above-mentioned problem that the display quality of the conventional liquid crystal display is affected by the non-uniform common voltage.

The invention provides a method for making a liquid crystal display have a uniform common voltage. First, a substrate is provided, and a plurality of scanning lines and a plurality of signal lines are formed on the upper surface of the lower substrate, so that each scanning line and signal line are interlaced to form a pixel matrix, and the pixel matrix includes a plurality of pixels, and then Forming a plurality of common electrode wires (common electrode) and a plurality of common electrode pads (pad) for transmitting a common voltage on the lower substrate, so that the common electrode pads are electrically connected to each of the common electrode wires, and an upper substrate is provided at the same time , forming a plurality of photoresist spacers on the lower surface of the upper substrate, so that each photoresist spacer corresponds to each common electrode pad on the lower substrate, and then forming a conductive material layer on the lower substrate The lower surface of the upper substrate, and cover the surface of the photoresist spacer, then combine the upper substrate and the lower substrate, so that the two are parallel to each other, and use the photoresist spacer on the surface of the upper substrate to support the two The gap between the substrates, and electrically connect the conductive material layer covering each photoresist spacer to each common electrode pad corresponding to each photoresist spacer, and finally fill the space between the two substrates with liquid crystal molecules , and seal the openings of the two substrates, wherein the impedance of the material forming the common electrode lead is smaller than the impedance of the material forming the conductive material layer. The conductive material layer may be a transparent indium tin oxide layer, and the common electrode wire may be formed of aluminum.

Since the present invention mainly forms a plurality of photoresist spacers on the upper substrate of the liquid crystal display, and then forms a conductive material layer on the surface of the upper substrate, and makes the conductive material covering the photoresist spacers The layer is directly electrically connected to the common electrode pad of the lower substrate, so as to be electrically connected to the common electrode wire through the common electrode pad. Therefore, the common voltage can be directly conducted to the layer covered with the photoresist through the common electrode wire on the lower substrate. The conductive material layer on the spacer, and because the photoresist spacer is evenly distributed on the entire display panel surface, so the entire conductive material layer can have a uniform common voltage, avoiding in the prior art, in the non-display area Silver glue dots are used to transmit the common voltage to the peripheral part of the conductive material layer of the upper substrate, but the common voltage in the middle part of the display panel is small and the common voltage is uneven due to the high resistance value of the conductive material layer.

Description of drawings

FIG. 1 is a basic structure diagram of a conventional liquid crystal display panel.

FIG. 2 is a schematic cross-sectional structure diagram of the liquid crystal display panel in FIG. 1 .

FIG. 3 is a basic structure diagram of the liquid crystal display panel of the present invention.

FIG. 4 is a schematic cross-sectional structure diagram of the liquid crystal display shown in FIG. 3 .

FIG. 5 is a schematic flowchart of a method for making a liquid crystal display have a uniform common voltage according to the present invention.

Explanation of reference signs

10 LCD panel 12 Display area

14 Non-display area 16 Signal line

18 scanlines 20 pixels

22 Lower base plate 24 Upper base plate

26 Tape and Reel Package 28 Pixel Electrode

30 Alignment film 32 Black matrix layer

34 Color filter 36 Opposite electrode

38 photoresist pillars 50 liquid crystal display panel

52 Lower base plate 54 Upper base plate

56 Display area 58 Non-display area

60 Scanning Lines 62 Signal Lines

64 Pixels 66 Common Electrode Leads

68 Common Electrode Pads 70 Photoresist Pillars

72 Conductive material layer 74 Color filter

76 Black matrix layer 80 Alignment film

82 Tape and reel package

Detailed ways

Please refer to FIG. 3 and FIG. 4 , FIG. 3 is a schematic diagram of the basic structure of the liquid crystal display panel 50 of the present invention, and FIG. 4 is a schematic cross-sectional structure diagram of the liquid crystal display 50 shown in FIG. 3 . The liquid crystal display 50 with uniform common voltage of the present invention includes a lower substrate 52, an upper substrate 54, which is arranged in parallel on the lower substrate 52, and a plurality of liquid crystal molecules (not shown), which are filled in the lower substrate 52 and the lower substrate 52. Between the upper substrate 54 . The surface of the lower substrate 52 of the liquid crystal display panel 50 of the present invention defines a display area 56 and a non-display area 58, and the surface of the lower substrate 52 also includes a plurality of scanning lines 60, a plurality of signal lines 62, and a plurality of scanning lines 60. Pixels 64 intersected with signal lines 62 in the display area 56, a plurality of thin film transistors (not shown) respectively located in each pixel 64, a plurality of common electrode wires 66, a plurality of common electrode pads 68 and an alignment film (not shown). Wherein, the material of the common electrode wire 66 and the common electrode pad 68 can be a metal material with high conductivity such as aluminum.

As shown in FIG. 4 , the lower surface of the upper substrate 54 includes a plurality of photoresist spacers 70 and a conductive material layer 72 covering the photoresist spacers 70 . The photoresist spacer 70 is used to support the gap between the upper substrate 54 and the lower substrate 52, and is evenly distributed on the surface of the upper substrate 54. For example, a photoresist spacer 70 can be provided in each pixel 20, The conductive material layer 72 is used as the opposite electrode of the display, as in the prior art, to provide a stable common voltage value on the entire surface of the upper substrate to enhance the effect of liquid crystal molecule rotation. Wherein, the upper substrate 54 also includes a plurality of color filters 74, a plurality of black matrix layers 76 and an alignment film (not shown), and the color filters 74 include a red filter 74a, a green filter 74b and There are three kinds of blue color filters 74c, and the color filters 74 of every three colors are a group to form a pixel 64, and the black matrix layer 76 is positioned at the junction of each color filter 74 and the upper substrate 54, so as to Prevent red, blue, and green colors from mixing and improve color contrast. In addition, the present invention also includes two polarizers (not shown), which are attached to the outer surfaces of the upper substrate 54 and the lower substrate 52 respectively.

Since each common electrode pad 68 is evenly distributed in the display area 56, and each common electrode pad 68 is electrically connected to a common electrode wire 66, and each common electrode pad 68 has its corresponding photoresist spacer 70, so the conductive material layer 72 covered on the photoresist spacer 70 can be directly electrically connected to the common electrode pad 68 corresponding to each photoresist spacer 70, and forms a conductive line with the common electrode wire 66. Pass. In addition, through the design of the circuit layout, some parts of the common electrode wire 66 can also be directly used as the common electrode pad 68, so that the conductive material layer 72 covering the surface of the photoresist spacer 70 and the common electrode wires 66 is directly electrically connected.

It is worth noting that the method of the present invention can also be applied to the technology of directly manufacturing the color filter structure on the glass substrate or thin film transistor (color filter on TFT, COT), or other liquid crystal display panel products.

Please refer to FIG. 5 . FIG. 5 is a schematic flowchart of a method for making a liquid crystal display have a uniform common voltage according to the present invention. First provide a substrate, then form a plurality of scanning lines, a plurality of common electrode wires and a plurality of common electrode pads for transmitting a common voltage on the upper surface of the lower substrate, and make the common electrode pads and the common electrode wires Electrically connect, and then form a plurality of signal lines, pixel electrode wires, thin film transistors and other necessary electronic components of the liquid crystal display panel, and make each signal line and scanning line interlaced to form a plurality of pixels. Then, provide an upper substrate, first form a plurality of photoresist spacers on the lower surface of the upper substrate, and make each photoresist spacer correspond to each common electrode pad on the lower substrate, and then A conductive material layer is then formed on the surface of the upper substrate and covers each photoresist spacer. Then make the upper substrate and the lower substrate parallel to each other and combine them, then use the photoresist spacers on the surface of the upper substrate to support the gap between the two substrates, and make the conductive material layer covering each photoresist spacer It is electrically connected with each common electrode pad corresponding to each photoresist spacer, and finally fills liquid crystal molecules between the two substrates, and seals the openings of the two substrates. Among them, a plurality of color filters can be formed on the surface of the upper substrate or the surface of the lower substrate. In addition, as in the prior art, the liquid crystal display of the present invention also includes an alignment film and two polarizers whose polarization directions differ by 90 degrees. The processes of respectively pasting the upper surface of the upper substrate and the lower surface of the lower substrate are well known to those skilled in the art, so details will not be repeated here.

Compared with the existing liquid crystal display, the liquid crystal display with uniform common voltage of the present invention uses the common electrode wire on the lower substrate to transmit the common voltage. Since the common electrode lead formed on the surface of the lower substrate can be made of a material with less impedance (in the embodiment of the present invention, aluminum with an impedance of 3-4Ω/□ is used to make the common electrode lead), for example, the same yellow light as the scanning line Etching process (photo-etching-process, PEP), so the common voltage can be effectively transmitted to the conductive material layer on the surface of each photoresist spacer, so that the common electrode on the surface of the upper substrate has a uniform common voltage, so The display quality of the display can be greatly improved. Not only does it not need to greatly modify the existing process of manufacturing liquid crystal displays, but the technology can also be applied to the production of large-size panels to improve the pass rate of products.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the claims of the present invention shall fall within the scope of the patent of the present invention.

Claims (18)

1. A method for liquid crystal display to have a uniform common voltage, the method comprising: A lower substrate is provided, and the surface of the lower substrate defines a display area and a non-display area; A plurality of scanning lines, a plurality of common electrode wires and a plurality of common electrode pads are formed on the upper surface of the lower substrate, and the common electrode wires are used to transmit a common voltage, and the common electrode pads are electrically connected to each of the common electrode wires. connect; A plurality of signal lines are formed on the upper surface of the lower substrate, and the signal lines and the scanning lines are interlaced to form a pixel matrix in the display area, and the pixel matrix includes a plurality of pixels; Provide an upper substrate; A plurality of photoresist spacers are formed on the lower surface of the upper substrate, and the distribution positions of each of the photoresist spacers correspond to the common electrode pads of the lower substrate; forming a conductive material layer on the lower surface of the upper substrate and covering the surface of the photoresist spacer; The photoresist spacer is used to support the gap between the upper substrate and the lower substrate, so that the upper substrate and the lower substrate are combined in parallel, and the photoresist spacers covering each of the photoresist spacers The conductive material layer is electrically connected to the common electrode pad corresponding to each of the photoresist spacers; and filling a plurality of liquid crystal molecules between the upper substrate and the lower substrate, and completing the sealing of the upper substrate and the lower substrate, Wherein the impedance of the material forming the common electrode lead is smaller than the impedance of the material forming the conductive material layer. 2. The method according to claim 1 further comprising the step of forming a plurality of thin film transistors on the upper surface of the lower substrate, and each of the thin film transistors is respectively arranged at the intersection of each of the scanning lines and each of the signal lines for As the switching element of each pixel. 3. The method according to claim 2, further comprising the step of forming a plurality of pixel electrode wires on the upper surface of the lower substrate to be electrically connected to the thin film transistors respectively. 4. The method according to claim 1, further comprising the step of forming a plurality of color filters on the lower surface of the upper substrate, and each of the color filters includes three kinds of filters of red, green and blue. 5. The method according to claim 1, further comprising a step of forming a plurality of color filters on the upper surface of the lower substrate, and each of the color filters includes three kinds of filters of red, green and blue. 6. The method according to claim 1, further comprising the step of forming a polarizer on the lower surface of the lower substrate and the upper surface of the upper substrate, respectively. 7. The method of claim 1, wherein the photoresist spacers are respectively provided in each of the pixels. 8. The method of claim 1, wherein the conductive material layer is a transparent ITO layer. 9. The method of claim 1, wherein the common electrode wire is formed of aluminum. 10. A liquid crystal display with uniform common voltage, comprising: A lower substrate, the upper surface of the lower substrate defines a display area and a non-display area, and the lower substrate includes: A plurality of scanning lines and a plurality of signal lines, and the scanning lines and the signal lines are interlaced in the display area to form a pixel matrix, and the pixel matrix includes a plurality of pixels; A plurality of common electrode wires are used to transmit a common voltage; A plurality of common electrode pads are electrically connected to each of the common electrode wires; An upper substrate is arranged in parallel on the lower substrate, and the upper substrate includes: A plurality of photoresist spacers are arranged on the lower surface of the upper substrate to support the gap between the upper substrate and the lower substrate, and the relative positions of each photoresist spacer correspond to each of the common electrode pads of the lower substrate; A conductive material layer is arranged on the lower surface of the upper substrate and covers each of the photoresist spacers, and the conductive material layer covering each of the photoresist spacers is respectively connected to each each common electrode pad corresponding to the photoresist spacer is electrically connected; and A plurality of liquid crystal molecules are filled between the upper substrate and the lower substrate, Wherein the impedance of the material forming the common electrode lead is smaller than the impedance of the material forming the conductive material layer. 11. The liquid crystal display as claimed in claim 10, wherein the lower substrate further comprises a plurality of thin film transistors located at intersections of each of the scan lines and each of the signal lines for serving as switching elements of each of the pixels. 12. The liquid crystal display as claimed in claim 10, wherein the liquid crystal display further comprises a plurality of pixel electrode wires respectively provided in each of the pixels and electrically connected to each of the thin film transistors. 13. The liquid crystal display as claimed in claim 10, wherein the liquid crystal display further comprises a plurality of color filters arranged on the surface of the upper substrate, and each of the color filters comprises three kinds of filters of red, green and blue piece. 14. The liquid crystal display as claimed in claim 10, wherein the liquid crystal display further comprises a plurality of color filters arranged on the surface of the lower substrate, and each of the color filters comprises three kinds of filters of red, green and blue piece. 15. The liquid crystal display of claim 10, wherein the display further comprises two polarizers respectively disposed on the upper surface of the upper substrate and the lower surface of the lower substrate. 16. The liquid crystal display of claim 10, wherein each of the photoresist spacers is respectively disposed in each of the pixels. 17. The liquid crystal display of claim 10, wherein the conductive material layer is a transparent ITO layer. 18. The liquid crystal display of claim 10, wherein the common electrode wire is formed of aluminum.

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