JPS6217750B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in the electrode structure of an electro-optical display device, particularly a liquid crystal display device, and more particularly to an improvement in an electrode pattern for time-division driving. Until now, particularly in liquid crystal display devices, a time division driving method has been adopted and a simplified electrode structure has been used. An advantage of adopting the time-division drive method is that the number of lead wires in the electrode structure used in the conventional static drive method can be significantly reduced. For example, in the time division drive electrode structure shown in FIGS. 1a and 1b, segment electrodes 102, 103,
104 and 105 are respectively the tip portions 10
6, 107, 108, 109 and 110 are combined, and a segment electrode combination 119 in which segment electrodes 112, 113 and 114 are combined with their respective tips 115, 116, 117 and 118 are placed on the upper substrate. 101, and on the lower substrate 120,
A segment electrode assembly 125 consisting of segment electrodes 123 and 124 having tips 121 and 122 joined together; a segment electrode assembly 130 consisting of segment electrodes 128 and 129 having tips 126 and 127 joined together; A segment electrode assembly 135 consisting of segment electrodes 133 and 134 and a segment electrode 136 are arranged, respectively. In a liquid crystal display device, these segment electrode assemblies are arranged so as to overlap each other vertically.
The liquid crystal is sandwiched between the upper and lower segment electrode assemblies in a sand-like manner, and the sealing and constant thickness of the liquid crystal is maintained by appropriate spacers. As a method of applying time-division driving to electrodes having such an electrode structure, for example, a pulse is applied to the electrode structure consisting of the segment electrode combinations 119 and 111 provided on the upper substrate 101 as a common electrode, and the pulse is applied to the other lower substrate 12D. Provided electrode combinations 120, 130
The electrode structure consisting of 135 and the segment electrode 136 is used as a display electrode, and the signals necessary to give the desired number are applied to the electrode assemblies 120, 130 and 135 and the segment electrode 136 in synchronization with the electrode assemblies 119 and 111. By doing,
Any desired number can be displayed. The combination of such a time-division drive system and an electrode assembly is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 49-1194 and 52-109388.
No. 51-14360, and US Pat. No. 3,760,403. However, in the time division drive method using the electrode structure as described above, the joint portion of the electrode assembly provided on one substrate overlaps the tip portion of the electrode assembly provided on the other substrate. When an electric field is applied to the upper and lower electrode structures, the liquid crystal display section displays an unnecessary display area 22 in addition to the desired display area 21, as shown in FIG. 2, and a sharp optical display image cannot be obtained. At the same time, the display unnecessary area 22 of the joint part 23
The electric field applied to this area is increased, which accelerates the deterioration of the liquid crystal 24 aligned in this area. SUMMARY OF THE INVENTION It is an object of the present invention to provide an electro-optical display device, particularly a liquid crystal display device, equipped with a segment electrode assembly that eliminates the above-mentioned drawbacks. Another object of the present invention is to provide an electro-optical display device, particularly a liquid crystal display device, which is capable of providing sharp optical display without blurring. Another object of the present invention is to provide a liquid crystal display device having an electrode structure that can prevent liquid crystal deterioration. An object of the present invention is to provide an electro-optical display device having at least two substrates on which a plurality of segment electrodes are disposed, in which the segment electrodes are respectively coupled at locations other than their tips to form a segment electrode assembly; This is achieved by an electro-optic display device in which a tip end of a segment electrode assembly disposed on one of the substrates and a tip end of a segment electrode assembly disposed on the other substrate substantially overlap each other. That is, the present invention is characterized in that it uses a novel electrode structure, and this electrode structure will be explained below with reference to the drawings. FIGS. 3a and 3b show the display electrode 301, respectively.
3 is a plan view of an electrode structure forming a common electrode 302. FIG. The display electrode 301 is a segment electrode assembly 3 consisting of segment electrodes 303 and 304.
10. Segment electrode assembly 312 consisting of segment electrodes 308 and 309 and segment electrode assembly 3 consisting of segment electrodes 306 and 307
11 and segment electrodes 305, each segment electrode assembly 310, 311, and 312 has a segment electrode distal end portion 313, 314, 315, 316, 31.
7,318,319,320,321,323,
The segment electrodes are connected to each other at locations other than 324 and 324, respectively. On the other hand, the common electrode 302 is connected to the segment electrode 3
Segment electrode assembly 332 consisting of 25, 329 and 331 and segment electrodes 326, 32
It has an electrode structure in which segment electrode assemblies 333 consisting of 7, 328 and 330 are arranged.
These segment electrode assemblies 332 and 333
is the tip part 33 of the segment electrode as described above.
4,335,336,337,338,339,
340, 341, 342, 343, 344, 34
Segment electrodes are connected to each other at locations other than 5, 346, and 347. In the present invention, when the display electrode 301 and the common electrode 302 are overlapped, the tip portions 313 and 334, 314 and 33 of the respective segment electrodes are overlapped.
5,315 and 336, 316 and 337, 317 and 338, 318 and 339, 319 and 341, 32
0 and 342, 323 and 343, 324 and 346,
321 and 344 and 322 and 345 can be arranged so as to substantially overlap. FIGS. 4a and 4b show an example of an electrode structure in which a 1/3 division method is adopted instead of the 1/2 division method shown in FIG. That is, in FIGS. 4a and 4b, the display electrode 401 is connected to the segment electrode combinations 403 and 40.
The other common electrode 402 has an arrangement of segment electrode combinations 406 and 407 and a segment electrode 408. These segment electrode assemblies 403, 4
04, 405, 407 and 408 are the aforementioned 1/
As in the case of the two-part method, the segment electrodes can be connected to each other at locations other than the tips thereof. The present invention can be applied to "union jack type" segment electrodes in addition to the "Japanese character" segment electrodes shown in FIGS. 3 and 4. The segment electrode used in the present invention is made of a transparent metal oxide such as indium oxide, tin oxide or an alloy of indium oxide and tin oxide, aluminum,
It can be formed from metals such as silver, copper, zinc, etc., and the formal method is to form these conductive films by vacuum evaporation method, sputtering method, etc.
A method of forming the electrode structure by etching as shown in FIG. 4 or FIG. 4 can be adopted. In addition, the above-mentioned electrode structure can also be formed by a screen printing method or the like. Furthermore, the segment electrodes used in the present invention may be suitably used when employing a field effect display mode, such as a twisted nematic liquid crystal mode, a guest-host liquid crystal mode, a hybrid liquid crystal mode, a cholesteric liquid crystal mode, or a nematic-malesteric phase transition liquid crystal mode. It is preferable that it be covered with an insulating material. Suitable insulating materials include inorganic compounds such as silicon monoxide, silicon dioxide, titanium oxide, and magnesium fluoride, or organic polymers such as polyvinyl alcohol, polyvinyl acetal, polyethylene, polyparaxylylene, polyamide, polyimide, and polyethylene fluoride. can be mentioned. The segment electrodes used in the present invention can be supported on a substrate having appropriate insulation properties.
The substrate can be selected from a wide variety of substrates, such as glass substrates, plastic substrates (e.g., polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, polyacrylate, polymethacrylate, natural rubber, polyethylene terephthalate, (polycarbonate resin, melamine resin, epoxy resin, etc.) are preferably used. The liquid crystal display device of the present invention can have a structure in which the liquid crystal is sandwiched between the segment electrode plates, and the gap between the electrode plates can be formed by a sealing material that also serves as a spacer. Such a sealing material is made by applying an epoxy resin adhesive or the like along at least one edge of the electrode plate by screen printing, and
It can be formed by stacking two electrode plates and then curing the adhesive under curing conditions. Suitable spacer materials such as glass fibers, glass beads, plastic beads, etc. may also be dispersed in the adhesive, and these spacer materials can be further disposed within the liquid crystal layer. Further, in the present invention, a pair of linear polarizing plates having polarization planes crossing each other at 90 degrees can be provided on both sides of the electrode plate. In addition, when using a reflective type display, for example, U.S. Pat.
The diffuser-reflector plate disclosed in each publication such as No. 105094 can be used. The liquid crystal that can be used in the liquid crystal display device of the present invention is not particularly limited, and smectic liquid crystal, cholesteric liquid crystal, or nematic liquid crystal can be used, but nematic liquid crystal is generally suitable. For example, nematic liquid crystals are disclosed in Japanese Patent Application Laid-Open Nos. 47-18783 and 48-1878.
No. 39381, No. 48-96560, No. 48-20541, No. 48
−96559, No. 49-129684, No. 49-134648,
No. 50-59351, No. 50-59352, No. 50-83355
No. 50-89342, No. 51-4137, No. 51-4138
No. 52-39685, No. 52-103387, No. 53-
114788, US Patent No. 53-129183, US Patent No. 54-2283, US Patent No. 3815972, US Patent No. 3876286, US Patent No. 3881806
No. 3915883, No. 3919105, No. 3960752
No. 3975286, No. 4001137, No. 4011173
No. 4020002, West German Published Patent No. 2024269,
Same No. 2123175, Same No. 2139628, Same No. 2261548
No. 2321632 and other publications. Further, the present invention includes an electrochromic display device in addition to the above-mentioned liquid crystal display device. At this time, as the electrochromic substance, US Pat. No. 4,073,570, US Pat.
Compounds disclosed in publications such as No. 2814824 can be used. According to the present invention, it is possible to provide a sharp optical display that does not cause blurring, and since there is no unnecessary display area at the joint unlike in the conventional electrode structure, the electric field applied to the liquid crystal is uniformly applied. Moreover, it does not increase, and has the advantage of being able to prevent liquid crystal deterioration to that extent. Hereinafter, the present invention will be explained according to examples. Example 1 Two glass substrates each having a thickness of 1.1 mm were prepared, and an indium oxide electrode pattern having the structure shown in FIGS. 3a and 3b was formed on each substrate. A silicon dioxide film was formed on the surfaces of these electrode plates, and this film was further rubbed with a cloth so that the electrode plates intersected each other at 90°. After that, the cell is assembled so that the rubbing directions are perpendicular to each other, and a mixed liquid crystal consisting of a cyclobiphenyl liquid crystal and a terphenyl liquid crystal having positive dielectric anisotropy is injected, and after sealing, a polarization plane is formed on each outer side of the cell. A pair of linearly polarizing plates orthogonal to each other was arranged. The liquid crystal display device thus produced was designated as Sample 1. As a comparative sample, a liquid crystal display device was prepared in exactly the same manner except that the electrode plates shown in FIGS. 1a and 1b were used in place of the electrode plates used in Sample 1. For each sample by storing these samples under an AC voltage of 3 volts at a temperature of 85°C and under conditions of 85% relative humidity for 100 hours, 200 hours, 300 hours, 400 hours and 500 hours, respectively. A forced aging test was conducted to observe the occurrence of bleeding and the degree of deterioration of the liquid crystal. The results are shown in Table 1 below.

[Table] In addition, in the comparative sample, deterioration of the liquid crystal began to be observed after 300 hours, but in sample 1, no deterioration of the liquid crystal was observed even after 500 hours. Example 2 In place of the electrode plate used in Sample 1, the electrode plate shown in FIG.
A liquid crystal display device was produced in exactly the same manner except that the electrode plates shown in FIGS. and b were used, and almost the same results as those obtained in Example 1 were obtained.

[Brief explanation of the drawing]

FIGS. 1a and 1b are plan views of an electrode plate having a conventional electrode structure. FIG. 2 is a sectional view showing an aspect of a liquid crystal display formed between a pair of electrode plates shown in FIGS. 1a and 1b. 3a and 4b and 4a and 4b are plan views of electrode plates having an electrode structure according to the invention. 301,401...Display electrode, 302,402
...Common electrode, 310, 311, 312, 33
2,333,403,405,406,407...
...Segment electrode assembly, 313, 314, 31
5,316,317,318,319,320,
321, 322, 323, 324, 334, 33
5,336,337,338,339,340,
341, 342, 343, 344, 345, 34
6,347,...Tip of segment electrode.

Claims (1)

[Claims] 1. In an electro-optical display device having at least two substrates on which a plurality of segment electrodes are arranged and whose surfaces are subjected to rubbing treatment, and a liquid crystal is arranged between the substrates, the segment electrode Segment electrode assemblies are formed in which the segments are joined together except for the parts, and the tips of the segment electrode assemblies disposed on one of the substrates substantially overlap with the distal ends of the segment electrode assemblies disposed on the other substrate. An electro-optical display device characterized in that: