JPS6292919A - Liquid crystal display element for multiplex driving system - Google Patents

Abstract

PURPOSE:To set the pattern width of a metallic part to large value and produce liquid crystal display elememts uniformly with a good yield by providing two MIM elements in series between a connection terminal and each picture element electrode. CONSTITUTION:An insulating film 2b is interposed between a metallic line 2a and the second metallic part 6, and an MIM element is constituted in a terminal connection part 5 which is the connection part between a metallic wiring part 2 and the metallic part 6. The first metallic parts 8a and 8b are formed on both sides of the wiring part 2, and transparent picture element electrodes 4 are formed on end parts of long-sized metallic parts 8b. By this constitution, an MIM element similar to that in the connection part 5 is constitut ed in a picture element connection part 7 also. Thus, a ratio of the picture element area of the liquid crystal part to the area of the MIM connection end face of the MIM element is reduced considerably and the width of the metallic part which connects the metallic wiring part and the picture element electrode is set to a considerably large value, and metallic parts are formed uniformly with a good yield by the normal process.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides metal-1nsula
The present invention relates to a liquid crystal display element that enables high-density multiflex driving using elements having nonlinear current-voltage characteristics such as tor-rnetal elements and varistors.

[Prior art]

Conventionally, in a multi-flex drive type liquid crystal display element in which a plurality of transparent pixel electrodes arranged in parallel along the metal wiring part are connected to a metal wiring part formed on a substrate by a metal part, the above-mentioned metal There are devices in which an element having nonlinear current-voltage characteristics is formed at the connection portion between the wiring portion and the metal portion.

For example, in the liquid crystal display element shown in FIG. 6, metal lines 12b...
are provided in the form of vertical stripes, and connection terminals 12a are formed at the ends thereof. The metal line 12b is connected to the connection terminal 12a.
The portions other than the portions are covered with an insulating film 12C, thereby forming a metal wiring portion 12. Transparent pixel electrodes 13 arranged in parallel along this metal wiring part 12 and the metal wiring part 1
2 are connected through metal parts 14a and 14b. That is, in the connection portion 14 between the metal wiring portion 12 and the metal portion 14b, the metal line 12b-insulating film 12C-metal portion 14b
By the combination of M I M (metal −1ns
ulator-metal) elements are formed.

As shown in FIG. 8, an equivalent circuit of a liquid crystal display element having this MIM element connects a parallel circuit 15 consisting of resistors R, I, 4 of the MIM element and capacitance CM It is connected in series to a parallel circuit 16 made up of capacitance CLC. In the above liquid crystal display element, the sixth
When turning on and off the voltage applied to each pixel electrode 13 in the figure, a voltage having the waveform shown in FIG. 9(a) is applied to the pixel electrode 13, and this voltage causes the pixel electrode The MIM elements corresponding to... are driven. Above M
As shown in FIG. 7, the IM element has a non-linear current-voltage characteristic. Therefore, when the pixel electrode is turned on, R,... takes a small value, and during the selection period 1. Meanwhile, a large amount of charge is charged in the liquid crystal section having the capacitance CLC. On the other hand, when OFF, RMIM has a large value, so the charge charged in the liquid crystal section is held during the non-selection period t2. As a result, the ratio V of the effective value of the voltage applied to the liquid crystal section during ON and OFF times is 4. rms/V OF
As shown in FIG. 9(b), F, rms was significantly larger than in the case where no nonlinear element was used, and high-density multiflex driving was possible.

However, the ratio of the effective value of the voltage required to obtain a multi-flex drive type liquid crystal display element that can withstand actual use.

,,rms/V. In order to realize FF, rmS,
It is necessary that CMIM <<CLC. For this purpose, the ratio S Lc/S MIM of the pixel area of the liquid crystal section to the area of the MIM coupling end face in the MIM element is 1.
It is known that it must be greater than or equal to 0000/1. For example, when the pixel size is 3QQg++', the pattern width of the connection portion 14 having the MIM element needs to be at least 18- or less.

Therefore, in forming the metal parts 14a and 14b, LS
It is necessary to use photolithography technology with a cleanliness close to that of the I manufacturing process, and furthermore, it is difficult to manufacture uniformly and with high yield under the above conditions for liquid crystal display elements that have a large area. This was problematic.

[Purpose of the invention]

The present invention has been made in consideration of the above conventional problems, and is configured so that the pattern width of the metal part connecting the metal wiring part and the pixel electrode can be set larger than that of the conventional liquid crystal display. The object of the present invention is to provide a multi-flex drive type liquid crystal display element that can be manufactured uniformly and with high yield through an element manufacturing process.

[Structure of the invention]

A multi-flex drive type liquid crystal display element according to the present invention connects a pixel electrode to a metal wiring part that is electrically connected to a connection terminal formed on a substrate, and connects the metal wiring part and the first metal part to a pixel electrode. In a multi-flex drive type liquid crystal display element in which an MIM element having non-linear current-voltage characteristics is formed at the connection part with the metal wiring part, the connection terminal and the metal wiring part are connected by the second metal part, and the metal wiring part and the The present invention is characterized in that an MIM element having non-linear current-voltage characteristics is formed at the connection portion between the two metal parts, so that the pattern width of the first metal part can be set larger than that of the conventional one.

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 to 5.

As shown in FIG. 1, the liquid crystal display element according to this embodiment includes metal wiring portions 2 on one glass substrate 1 disposed facing each other, and metal wiring portions 2 on each of the metal wiring portions 2. Correspondingly, the metal wiring portion 2 and the separate connection terminals 3 are formed in a vertical striped shape. The connection terminal 3 is made of Ta, Cr-Cr-Ni, ITO, or the like. As shown in FIG. 2, the metal wiring section 2 is formed by covering the surface of a metal line 2a such as Ta, Cr-Cr-Ni, etc. with an insulating film 2b such as Tazos-3in or -3iNa. 2 and the connecting terminal 3 are connected by a second metal portion 6 made of Ta-Cr-Cr-Ni or the like. Therefore, the insulating film 2b is interposed between the metal line 2a and the second metal part 6. With this structure, an MIM element is configured in the terminal connection portion 5, which is the connection portion between the metal wiring portion 2 and the second metal portion 6.

Further, as shown in FIG. 3, on both sides of the metal wiring section 20,
First metal part 8a-8 made of Ta, Cr-Cr-Ni, etc.
b is formed and the first metal portion 8b is formed with a long dimension.
A transparent pixel electrode 4 is formed on the end of the pixel electrode 4 . With this structure, the same MIM element as the connection part 5 is configured also in the pixel connection part 7, which is the connection part between the metal wiring part 2 and the first metal part 8b. Here, the above-mentioned first metal part 8
a, 8b and the second metal portion 6 are formed to have the same thickness and the same width.

The multi-flex drive type liquid crystal display element having the above configuration is manufactured through the following steps.

(1) First, as shown in Figures 4 and 5 (a),
Glass substrate 1 (Corning #7
A Ta thin film is formed on the entire surface (such as 059), and after the photo process is completed, dry etching is performed. As a result, the metal lines 2a arranged in vertical stripes...
・corresponding to this metal line 2a and metal line 2a
A large substrate 20 for anodization treatment is obtained by patterning a plurality of sets of one unit wiring pattern 20a consisting of the wiring pattern 20a and the connecting terminals 3 to be separated. A common lead-out line 21 for connecting to a power source during anodization is formed at one end of the glass substrate 1, and a branch line 21a of this common lead-out line 21 and a metal line 2a of each wiring pattern 20a are formed at one end of the glass substrate 1.
... is connected to one end.

(2) Next, the large substrate 20 is immersed in a 0.01 wt% citric acid aqueous solution, and an external power source is connected to the common extraction line 21 to perform anodic oxidation. As a result, Fig. 5(b)
As shown in FIG. 2, a metal wiring portion 2 is formed by covering the surface of the metal line 2a with an insulating film 2b of TazOs. At this time, the connection terminal 3 is separated from the common extraction line 21 and is not energized, so that anodization is not performed.

(3) Next, on the glass substrate 1, at a predetermined interval,
The first metal parts 8a and 8b shown in FIG. 1 are formed, and at the same time, the second metal part 6 is formed with the same width.

The above process is performed in the first metal part 8a shown in FIG. 5(cf).
The manufacturing process of 8b will be representatively explained. First, as shown in FIG. 2(c), a photoresist is coated on the glass substrate 1 that has undergone the step (2) above, and a pre-bake process is performed.
)do.

Next, the back side of the glass substrate 1 is covered with a photomask 31, leaving the formation areas of the metal wiring part 2 and the first metal parts 8a and 8b, and after UV light is irradiated from the back side, the first Photoresist 32a on metal parts 8a and 8b.
32b is peeled off from the glass substrate 1. Next, a Ta thin film is formed by a sputtering method, and the photoresist on parts other than the metal parts 8a and 8b is removed by a lift-off method, thereby forming the first metal part 8 shown in FIG. 5(d).
a and 8b are formed.

(4) Finally, after forming the pixel electrode 4 by sputtering so as to cover the end of the first metal portion 8b with the end of the pixel electrode 4, the large substrate 20 is separated by the dividing line 22.
... to obtain the glass substrate 1 on which one unit of the wiring pattern 20a shown in FIG. 1 is formed.

(5) Thereafter, using the glass substrate I formed by the above steps, the manufacturing process of a normal liquid crystal display element is performed.
A multi-flex drive type liquid crystal display element is manufactured.

In the above configuration, the liquid crystal display element according to this example is
As shown in FIG. 1, two M
IM elements will be provided in series. Moreover, the first
Since the metal parts 8a and 8b and the second metal part 6 are formed of the same material, the same width, and the same thickness, each of the above MIM
The elements will have approximately the same capacitance. As a result, the capacitance between the connection terminal 3 and each pixel electrode 4 is
The number of MIM elements is 2 compared to the conventional example in which only one MIM element is formed. That is, the capacitance C is expressed as C-ε□ and is proportional to the area S. Therefore, in order to have the same capacitance as the conventional example, the first metal parts 8a and 8b and the second metal part 6 teeth,
This means that while the thickness is the same as the conventional one, the width can be twice that of the conventional one. For example, conventionally, the pixel size was 300t.
The pattern width of the first metal portions 18a and 18b, which was required to be less than 1 day per m6, can now be formed to be less than 36 days.

〔Effect of the invention〕

As described above, in the multi-flex drive type liquid crystal display element according to the present invention, there are two
Since the configuration is such that two MIM elements are provided in series, the following effects can be achieved.

1) The ratio SLC/SWIM of the pixel area of the liquid crystal section to the area of the FvlTM coupling end face in the MIM element can be significantly reduced from the conventionally required 10000/1. This makes it possible to set the width of the metal part that connects the metal wiring part and the pixel electrode to be much larger than before, and as a result, the LSI-like process that was conventionally used to form the metal part is no longer necessary. It disappears.

Therefore, by the normal process for manufacturing liquid crystal display elements,
It can be manufactured uniformly and with good yields, significantly improving productivity.

2) Functional failure of the MIM element in the pixel electrode connection part can be reduced by the MrM element in the terminal connection part. That is,
Conventionally, if the MIM element in the pixel electrode connection part malfunctioned, the pixel would become a display defect, leading to a decline in display quality, but this has become a problem in actual use due to the function of the MIM element in the terminal connection part. It is possible to maintain a level of display quality that is not

3) Compared to the conventional example, the OFF resistance of the MIM element is higher, so the time constant is -(RL CRM I H/R
LC+RMIM) (CLC+CMIM) also increases, and the discharge rate from the liquid crystal section becomes significantly slower.

As a result, as shown in Figure 9(C), 0N-OFF
The ratio of the effective value of the applied voltage at the time V ON, rms/V
OFF, rms is increased, and higher contrast can be achieved than in the past.

[Brief explanation of drawings]

Fig. 1 is a plan view showing one embodiment of the present invention, and Fig. 2 is a plan view showing an embodiment of the present invention.
Figure 3 is an enlarged cross-sectional view taken along line A-A in Figure 1, and Figures 4 and 5 (a) to (d) show the manufacturing process in Figure 1. FIG. 6 is a plan view showing a conventional example, FIG. 7 is a graph showing current-voltage characteristics of an MIM element, FIG. 8 is an equivalent circuit diagram of a liquid crystal display element having an MIM element, and FIG. Figure (a) is a driving waveform diagram of a liquid crystal display element having an MIM element, and Figure (b) is a voltage waveform diagram applied to the liquid crystal section of a liquid crystal display element having a conventional MIM element.
FIG. 3(C) is a voltage waveform diagram applied to the liquid crystal section of a liquid crystal display element having an MIM element according to an embodiment of the present invention. 1 is a glass substrate, 2 is a metal wiring section, 2a is a metal line, 2
b is an insulating film, 3 is a connection terminal, 4 is a pixel electrode, 5 is a terminal connection part, 6 is a second metal part, 7 is a pixel connection part, and 8a and 8b are first metal parts. Patent Applicant: Sharp Corporation Figure 1/Getsu Figure 2 Figure 3 Figure 4 Figure 5 (a) Figure 6 Figure 7 Figure 8] 51◇ Figure 9 (a) Period of one action ii'M 蓼Period Figure 9 (b) ゛B Translation: I-Select Period Pavilion

Claims (1)

[Claims] 1. A metal wiring part that is electrically connected to a connection terminal formed on a substrate and a pixel electrode are connected by a first metal part, and a non-linear structure is formed in the connection part between the metal wiring part and the first metal part. In a multi-flex drive type liquid crystal display element in which an MIM element having a current-voltage characteristic is formed, the connection terminal and the metal wiring part are connected by a second metal part, and the metal wiring part and the second metal part are connected. 1. A multi-flex drive type liquid crystal display element, characterized in that an MIM element having nonlinear current-voltage characteristics is formed in a portion thereof. 2. The multi-flex driving type liquid crystal display element according to claim 1, wherein the first metal part and the second metal part are formed to have the same width.