JPH01125861A - Nonlinear two-terminal element for display panel - Google Patents

Abstract

PURPOSE:To enable the mass production of diodes for an active matrix large- area display by a method wherein a first electrode layer is formed, an organic thin film characteristically non-linear and containing a compound equipped with a phthalocyanine skeleton is formed on the first electrode layer, and then a second electrode layer is formed on the organic thin film. CONSTITUTION:Provided are a first electrode layer 11, an organic thin film 12 characteristically non-linear and containing a compound quipped with a phthalocyanine skeleton, and a second electrode layer 13 formed on the organic the organic thin film 12. Making use of the non-linearity of voltage and current in the organic thin film 12 equipped with a phthalocyanine skeleton and the Schottky effect in presence between the organic thin film 12 and the electrode layers, the organic film 12 may be formed by printing. This design results in non-linear two-terminal elements by using which a liquid crystal display panel may be larger in size and more homogenous in construction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a nonlinear two-terminal element suitable for use in driving a display panel such as a liquid crystal display panel, particularly an active matrix type device.

[Prior Art] As a method of increasing the number of pixels without reducing the contrast ratio of a display panel such as a liquid crystal display panel, an active matrix method in which each pixel is provided with a switching element such as a thin film transistor or a nonlinear two-terminal element is being considered. It has been.

In particular, an active matrix method using a nonlinear two-terminal element can be expected to have a higher yield because the manufacturing process of the element is simpler than an active matrix method using a thin film transistor.

FIG. 5(A) shows a cross-sectional view of a liquid crystal display panel using a nonlinear two-terminal element as a switching element, and FIG. 5(B) shows its equivalent circuit diagram. This display panel has a three-layer structure of a conductive film, an insulating film, and a conductive film, or a conductive film, a semiconductor film, and a conductive film. In the figure, 21 is a glass substrate, 22 is a transparent electrode,
23 is a polarizing film, 24 is a TN (twisted nematic) liquid crystal, 25 is an alignment film, 26 is an electrode layer, 27 is an insulator layer or semiconductor layer 28 is a liquid crystal cell, and 29 is a nonlinear two-terminal element.

As a nonlinear two-terminal element used in a display panel, an old M element having a metal film-Ta20s (insulating film)-conductive film structure is known (Japanese Patent Laid-Open No. 106181/1981).

In addition, hydrogenated amorphous silicon (a-5t:H) (
It has a three-layer structure in which an R film layer of hydrogenated amorphous silicon carbide (a-5iCx:H) (Japanese Patent Application Laid-open No. 60-50962) is formed between conductive films. Nonlinear two-terminal elements and devices in which these nonlinear two-terminal elements are connected in a ring have been studied.

[Problems to be solved by the invention] However, in MIM diodes, in order to obtain nonlinear characteristics, the thickness of the insulating film must be 500 to 600 Å or less, and it is necessary to make such an extremely thin film uniform over a large area. It is difficult to form.

On the other hand, a-5i:Hla-5iC, :)1. a-5i
In a nonlinear two-terminal device using a semiconductor film such as N or :H,
The thickness of the semiconductor film is considerably thicker than the thickness of the insulating film of the MIM element, at 1000 Å or more, and is therefore preferable for uniform formation over a large area. However, to form these thin films, sputtering method, CVD
Since it is necessary to use a method such as a method, a vacuum apparatus must be used to manufacture the nonlinear two-terminal element. Therefore, large-scale equipment is required to mass-manufacture active matrix type display panels for large-area display, and manufacturing costs also increase.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems, to be able to cope with the mass production of active matrix type diodes for large-area displays, to be able to be manufactured with small equipment, and to reduce manufacturing costs. The object of the present invention is to provide a nonlinear two-terminal device with high performance.

[Means for Solving the Problems] In order to achieve such an object, the present invention includes a first electrode layer and a compound having a phthalocyanine skeleton formed on the first electrode layer, and has nonlinear characteristics. an organic thin film having;
The present invention provides a nonlinear two-terminal element for a display panel, characterized by comprising a second electrode layer formed on an organic thin film.

As the substrate of the nonlinear two-terminal element of the present invention, for example, an insulating substrate made of glass substrate, epoxy resin, polyester, polyurethane, polyimide, etc. can be used.

The electrode layer of the nonlinear two-terminal element is made of a conductive film, and is formed by various known methods such as sputtering, vapor phase, electroless plating, and spraying.
A metal thin film such as Ti, Alt, Ni, etc., a transparent conductive film such as ITO (indium tin oxide), InzOs, etc., an Ag paste in which metal particles are dispersed in a binder, a paste, a Cu paste, etc. can be used. Note that the thickness of the first and second electrode layers is usually 0.1 to 0.0.
It is 2 μm.

As an organic thin film containing a compound having a phthalocyanine skeleton between conductive layers, a mixture of phthalocyanine and a vinyl polymer such as polystyrene or polyvinyl alcohol (J
, Chem, Phys, Volume 71, No. 3 (1
97!1, pp. 11211-1217), phthalocyanine or a derivative thereof, a mixture of a phthalocyanine or a derivative thereof and a thermosetting resin, a phthalocyanine polymer, a mixture of a phthalocyanine polymer and a phthalocyanine or a derivative thereof can be used.

Here, the phthalocyanine derivatives include phthalocyanine metal complexes, tetraaminophthalocyanine metal complexes,
Examples include a tetra-tert-butylphthalocyanine metal complex, a te]heracarboxyphthalocyanine metal complex, and the like.

Examples of the thermosetting resin include polyimide, polyamide, polyester, polyurethane, phenol resin, epoxy resin, silicone resin, and acrylic resin.

Further, as the phthalocyanine polymer, for example, polymetal phthalocyanine imide (B, N).

Achar et al.: Journal of Po.
lymer 5science.

Polymer Chemistry Editor
n, Vol, 20. pp, 2773-2780 (198
2); B.N., Achar et al., 1bid.
, Vol. 20. pp:2781-2789 (198
2)) Polymers containing a phthalocyanine skeleton in the polymer main chain or polymer side chain, such as a copolymer of 2-vinylpyridine and styrene bound to a phthalocyanine metal complex (Yokazu Hirahara et al., Applied Physics) J.Vo.
l, 52. No. 12' (1983), pp. tos.
t-1057) can be used.

In addition, if the weight ratio of phthalocyanine or its derivative to the vinyl polymer, thermosetting resin, or phthalocyanine polymer (phthalocyanine derivative/thermosetting resin or phthalocyanine polymer) is 1 or more, I-V
As long as nonlinear characteristics are obtained and the phthalocyanine or its derivative is uniformly dispersed, it is preferable that the weight ratio is large.

The thickness of the organic thin film containing the above compound having a phthalocyanine skeleton is preferably in the range of 1 μm to 20 μm. If the film thickness is too small, the organic R film is likely to cause cracks, and if the film is too thick, the resistance of the nonlinear two-terminal element becomes too large, which is not preferable.

As a method for forming an organic thin film, printing techniques such as screen printing and offset printing can be used.

The size of the nonlinear two-terminal element obtained as described above is usually XX5 μm to 100×100 μm.

[Function] According to the present invention, the organic thin film is formed by utilizing the nonlinear characteristics of voltage and current of a compound having a phthalocyanine skeleton, which is an organic thin film, and the Schottky characteristic between an organic thin film containing a compound having a phthalocyanine skeleton and an electrode layer. Since it can be formed by printing technology, it is possible to produce a nonlinear two-terminal element that can be made larger and more uniform for liquid crystal display panels and the like.

[Embodiments] Hereinafter, uninvented embodiments will be described in detail with reference to the drawings.

Example 1 An ITO electrode 11 was formed on a glass substrate by a spray method, and patterned by a photolithography process. On the obtained tTQ electrode pattern, phthalocyanine, polyamide and dimethylacetamide were added in a weight ratio of 1:1:1.
The solution mixed in step 4 was applied to a thickness of about 10 μm by screen printing, and baked in air at 300° C. for 60 minutes to form an organic thin film 12. Next, silver paste was applied by screen printing to form scanning electrodes 13, thereby obtaining a nonlinear two-terminal element.

Fig. 1(A) shows a plan view of this embodiment, and Fig. 1(B) shows a plan view of this embodiment.
) shows a sectional view taken along line 8-Δ' in FIG. 1(A).

In the figure, 11 is a transparent electrode, 12 is an organic @1 model, and 13 is a scanning electrode.

FIG. 2 shows an I-■ characteristic diagram of the nonlinear two-terminal element of this example. As shown in the figure, when the electrode materials of the two terminals are different, the symmetry of the 1-v characteristic is lost.

Embodiment 2 FIG. 3(A) shows a plan view of another embodiment of the present invention.
FIG. 3(B) shows a sectional view taken along line BB' in FIG. 3(A). An ITO electrode 11 is formed on a glass substrate by a spray method, and patterned by a photolithography process. Below, a solution mixed with phthalocyanine prepared in the same manner as in Example 1 was applied onto the TTO electrode pattern, and as in Example 1, the organic thin film was baked in air.
2 was formed. Next, silver paste was applied by screen printing to form scanning electrodes 13, thereby obtaining a ring-connected nonlinear two-terminal element. This nonlinear two-terminal element has a symmetrical I because the opposing electrode materials are made of the same material.
-V characteristics were obtained.

Embodiment 3 FIG. 4 (8) shows a plan view of still another embodiment of the present invention, and FIG. 4 (B) shows a cross-sectional view taken along line c-c' in FIG. 4 (8). . In the figure, 14 is an electrode. First, an ITO electrode 11 was formed on a glass substrate by a spray method, and patterned using a photolithography process. Next, silver paste is applied by screen printing method to the electrode 14.
was formed. Next, a solution mixed with phthalocyanine prepared in the same manner as in Example 1 was applied onto the TTO electrode pattern by screen printing, and baked in air in the same manner as in Example 1 to form a thin film 112. Next, silver paste was applied by screen printing to form scanning electrodes 13. The nonlinear two-terminal element thus obtained had symmetrical IV characteristics because the opposing two-terminal electrodes 13 and 14 were made of the same silver paste.

[Effects of the Invention] As explained above, according to the present invention, since an organic thin film containing a compound having a phthalocyanine skeleton can be coated by printing technology, it is easy to increase the area of the device, and the manufacturing method can be simplified. It's convenient.

Furthermore, unlike conventional nonlinear two-terminal devices, it is not necessary to use a vacuum device when forming an organic thin film having nonlinear characteristics, so manufacturing equipment can be downsized and manufacturing costs can be reduced.

Furthermore, a liquid crystal cell using the nonlinear two-terminal element of the present invention has good voltage holding properties.

The nonlinear two-terminal element according to the present invention is particularly useful for driving display panels such as liquid crystal display panels, electrochromic display panels, PLOT display panels, fluorescent display panels, electroluminescence display panels, and plasma emission display panels, especially those using an active matrix method. It is effective for things.

[Brief explanation of the drawing]

FIGS. 1(A) and (B) are a plan view and a side view showing an embodiment of the present invention, respectively. FIG. 2 is a characteristic diagram showing the IV relationship of a nonlinear two-terminal element. 8) and (B) are a plan view and a side view showing another embodiment of the present invention, respectively; Figures 4 (8) and (B) are a plan view and a side view showing another embodiment of the present invention, respectively; The side view and FIGS. 5(8) and CB) are a sectional view and an equivalent circuit diagram, respectively, showing an example of a conventional liquid crystal display panel. 11... ITO electrode, 12... Organic thin film, 13... Scanning electrode, 14... Electrode. Figure 1 // Figure 3 Figure 4 Figure 5 (A) Funeral Figure 0 (H)

Claims (1)

[Claims] 1) A first electrode layer, an organic thin film containing a compound having a phthalocyanine skeleton formed on the first electrode layer and having nonlinear characteristics, and a second electrode layer formed on the organic thin film. Nonlinear 2 for display panel characterized by having
terminal element.