JPS5842027A - Production for liquid crystal display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Real #! The present invention relates to a method of manufacturing a large display device using AFi liquid crystal. More specifically, the present invention relates to a method for manufacturing a matrix type liquid crystal display device which combines an Fi liquid crystal display panel with non-resistant elements and has improved display characteristics.

In recent years, the application of liquid crystal display devices has progressed, and they are now being used in large quantities as display devices for wristwatches, calculators, and other small electronic devices.

In order to further expand the field of application of this liquid crystal display device, it is necessary to increase the display capacity, but in conventional liquid crystal display devices, the rise of the voltage-contrast characteristic is not very steep. Since there is not much difference between the effective values applied to one selected point and the non-selected point or the #'i-selected point, resulting in crosstalk, there is a drawback that multi-digit driving of several tens of digits is the limit. Therefore, in order to increase the display capacity of a liquid crystal display device, an active matrix type device that combines a nonlinear element and a liquid crystal display device has been considered, and TPT using amorphous silicon or polysilicon is considered.
Various approaches have been taken, such as varistors using diodes, lubrication, zinc oxide, etc.

Nonlinear elements (hereinafter referred to as MIM elements) having a (Metax-xr+5u1at*r-Meta1) structure (hereinafter referred to as MIM elements) have a simple element configuration, so the manufacturing process is relatively simple, and the element design is easy. It has certain advantages. This MIM element is an insulator in which a current flows due to the tunnel effect, Schottky effect, or Poole-Frenkel effect and exhibits nonlinear voltage-current characteristics as shown in #i1~, where C is AX and Ta.

Purified materials such as Nb, Ti, 81, etc., inorganic materials such as nitrogen-doped gold compounds or chalcogenide glass, and organic thin films such as KFi can also be used.

Pre-deposited @Oxide f: When used as an insulator for MxM devices, the conduction mechanism varies depending on the film thickness, with tunneling effect being dominant at 50-100 A, and Tsumashitke effect and Fuhr-Frenkel effect being dominant at 100-1000 A. It is said to be occupied. In the combination of a liquid crystal display device and an MIM element for the purpose of the present invention, the pool and
7 It seems desirable to use the so-area that exhibits the Lenkel effect.

In that region, the voltage-electricity R% characteristic described above is expressed by the Poole-Frenkel formula (11). When driven by MzMz, the actual V
The effective value ratio of 10N101'ν applied to the C@crystal becomes larger than the effective value ratio of OMlo P F of the voltage averaging method itself, and more multi-digit matrix driving becomes possible. However, when combined with a liquid crystal display device,
The equivalent circuit for one pixel is OMI for the capacitance as shown in the Ml diagram.
It can be considered that an MIM element 1 in which M and a nonlinear resistance component RMIM are connected in parallel, and a liquid crystal part 2 in which a capacitance component CLO and a resistance component RLO are connected in parallel are connected in series.

However, in these Ml and M elements, a difference occurs in the voltage -1tfIL% property depending on the polarity of the applied voltage, and the difference t
-It would be extremely difficult to eliminate it completely. .

When combining Ml elements with polarity differences in a liquid crystal display device, for example, the voltage -
When driving L7' with a voltage averaging method of % bias in combination with an M-electronic crystal display device having current characteristics, M I
Mt4] Voltage - wLfIl, 'Due to the tyg difference in #, the voltage waveform actually applied to the liquid crystal part has a polarity difference (part A and part 3 in #I3 diagram), and the liquid crystal part has a symmetrical alternating waveform. Instead, if we apply an alternating waveform biased with [flt 5 - and apply the same waveform as in the 9 case,
It becomes.

Driving the liquid crystal t-[ff increases the electrochemical reaction of the liquid crystal itself and the electrochemical reactions of impurities contained in the liquid crystal, which is undesirable because it significantly shortens the life of the liquid crystal display device.

The present invention aims to eliminate these drawbacks. Two M elements are connected in parallel in a direction that cancels out the polarity difference in voltage-W current characteristics, and combined with a liquid crystal display device.

A description will be given below according to examples.

Example 1 Pyrex glass substrate 40
A transparent conductive film of +8nO1) was formed and photoetched to form all electrodes 41 and 4 (14IO(A)).

Next, KTaTa full-film tube sputtering was performed on top of it and patterned into the shape shown in the shaded area in Fig. 4(B).
Anodic fermentation is performed in an aqueous solution of wt nitrogen to form a filamentous film on the surface.

Next, the unnecessary portions of the anode exposed film and the Ta thin film are etched by 76° to form the M/MX element forming portions 42a, 42b and the lead portions 45. Next, 5 people carried out heat treatment in air at 250°C for 1 minute to photo-etch the Orum U thin film deposited on the MX element 44a.

FIG. 5 shows the positional relationship between the MIM elements 44a and 44b of the OM element forming part forming the OM element 44b and the lead part 45', the fi element electrode 41, and the lead parts 45 and 45'.

The MIM% slave side substrate 40 and the opposite substrate provided with the strip-shaped transparent poles thus made are coated with polyimide resin, fired, and rubbed with a cotton cloth to perform liquid crystal alignment treatment. Two deflection plates are placed on the outside of both substrates, and the individual axis is the orientation axis of the liquid crystal molecules. A liquid crystal display device is made by gluing it to fit the screen.

Implementation f12 Similar to Example 1, a pixel electrode 61'ft is placed on the transparent substrate 6D.
Figure 6 (A) after formation and Ta thin film sputtering.
Pattern it into the shape shown in K and perform anodic fermentation.
.

Next, protect the M element forming parts 11i62a and 62b with photoresist, and photo-etch the unnecessary parts to form the lead part 6.
form 5. [FIG. 6(B)→(C)] The side pressure first layer Ta is exposed in a portion 64 indicated by a thick solid line in FIG. 6(C). At this time, it is desirable to perform etching so that the etched shape of the side surface is tapered.

Next, an Or-Au thin film that is the second layer metal is vapor-deposited, and the Or-Au thin film t7 that is the second layer metal is etched so as to cover the exposed Ta s64 on the side surface of the lead portion 65 of the first layer Ta. 65 and MIM elements 66a and 66bf are formed (FIG. 6(D)). FIG. 7 shows a cross section taken along the dashed-dotted line in FIG. 6(D).

By making the structure similar to that of a wire, the electrical connection between the lead part made of the first layer metal and the lead part made of the second layer metal can be achieved. Differences in wiring resistance can be eliminated, and when two M elements are connected in parallel in opposite directions, the polarity difference in current characteristics can be minimized.

Although the embodiments have been described above, the present invention is not limited to the above embodiments.

For example, when it comes to substrates, we use not only Pyrex glass, but also
When considering flatness, cost, etc., soda lime glass is advantageous; however, when using a soda lime glass substrate, a pansivation film is required to prevent elution of alkaline components.

Also, the material of the 1MXM element is not limited to Ta but M.

Gold doped with various **16 or other elements such as Wb, Ti, Mo, Hf, etc. or other elements such as the metals KN, C, H, etc. is used as the first layer electrode, and these - Ichimoku Kinho's anodic oxide film. can be used as an insulating film. Furthermore, as the counter electrode of the KMIM element, basically any #i conductor can be used.
For example, using the same material as the first layer metal, or using Ni
, Or, Cu.

It is also possible to use Au or an alloy thereof.

Regarding the liquid crystal display method, the present invention is also applicable to Twisted States 9-Done! Although the tick method is described above, there are other methods, such as the nine-guest-host method in which a dichroic dye (guest) is mixed into the liquid crystal (host), and the nine-guest method (using the dynamic scattering effect of liquid crystal molecules).
D8M) can also be used, and the liquid crystal alignment method can be any method commonly used in each method.

Also, the shape of the MIM resistor and pixel electrode depends on the electrical characteristics.
For example, as shown in No. 81kK, the pixel electrode 8
1t-Polygonal KLM M element 82t-By providing a gap between adjacent pixel electrodes, it is possible to avoid an unnatural pixel electrode shape as in the above embodiment IPI 110 or 2.

By configuring as explained above, two MIM
A liquid crystal display value at can be obtained by connecting the tags in parallel in opposite directions. The equivalent circuit of the liquid crystal display device in this case is the 9th WJ
It can be regarded as

In addition to the method of connecting two M elements ft, there is also a method of connecting two 0 M elements t in series with the curve of the ILT column. It can be canceled out, but in that case, as shown in Part 1 10-101, the voltage for one M element - voltage fl
L characteristics (a, b) The voltage-current characteristics are plotted as C versus K. On the other hand, MI of parallel connection according to the present invention
M element 1i: (14'L plot has a voltage-wL current characteristic, and when connected in series, the slope [corresponding to Poole-Frenkel constant: β in equation (1)] is large.
In the case of combining the M element and the liquid crystal display device, it can be considered that the non-edge type nature of the M element is used as a switching element, and the larger β is, the more effective it is. It can be said that it is more desirable to connect two M elements in parallel since it is possible to perform multi-lux driving with a narrow tutee ratio.

As described above, according to the present invention, it is possible to easily obtain a liquid crystal display device 11-W with a longer life than when one V-type M element is combined with a liquid crystal display device.

[Brief explanation of drawings]

Figure WA1 shows the voltage-current characteristics of #iM x M element. FIG. 2 shows an equivalent circuit for one pixel when M elements are combined in a liquid crystal display fl position. Figure 13 shows waveforms when a uMIM element and a liquid crystal display device are combined and driven by the voltage averaging method. FIG. 4 is for explaining the manufacturing process of two anti-parallel connected M elements according to the first embodiment of the present invention. FIG. 5 is a schematic diagram of the M element part of two antiparallel connected M elements according to Embodiment 1 of the present invention. FIG. NA6 and FIG. 7 are diagrams and cross-sectional views illustrating the manufacturing process of two antiparallel MXM elements and lead parts in Example 2 of the present invention. FIG. 8 shows another embodiment in which the shape of the pixel electrode is changed. FIG. 9 shows an equivalent circuit when two anti-parallel MIM elements according to the present invention are combined with a liquid crystal display device. Figure 10: 1 MIM element, 2 MIM elements connected in reverse series, and 2
This shows the voltage-current characteristics when connected in reverse parallel. Applicant Daini Seikodai Co., Ltd. Agent Patent Attorney Mogami Figure 1 Figure 2 Figure 3 - Figure 8 Figure 9 Figure 10

Claims (2)

[Claims] (1) A plurality of display pixels t-south, each of which has an insulator (M@4a1-4naulator-
A non-Iw type element (Metal (abbreviated as MIM)) having a structure
In the manufacturing method of a tube-bonded liquid crystal display device (hereinafter referred to as an MIM device), the method includes forming a pixel turtle/pole, forming and patterning a first layer metal thin film, and anodic cleaning the surface of the first layer metal thin film and anode cleaning film. Through the steps of removing unnecessary parts, heat treatment, forming the second layer@pseudo-thin film, and patterning, the two M elements are connected in parallel in a direction that cancels out the polarity difference in their voltage-current characteristics. A method of manufacturing a liquid crystal display device characterized by having a structure in which pixels KI are connected. (2) The lead part of the first layer of metal to the MIM element has a structure in which the upper surface is an anodized film and the first layer of gold is exposed on the side, and the second layer of metal is covered with the exposed part of the eyelet. From K, the patent claim is characterized in that the lead part of the first metal layer to the M element of the M process and the lead part of the second metal layer to the M part of the M process maintain electrical continuity with each other. A method for manufacturing a liquid crystal display device according to scope 1.