JPH03158831A - Electrochromic display - Google Patents

Abstract

PURPOSE:To enhance the resistance of electrochromic display picture elements to the electric field corrosion by bleeding out of an electrolyte by forming circuit electrodes connected respectively to the picture electrodes with indium-tin- oxide layers stacked and formed via barrier layers on the wiring patterns formed on the substrate surface of a circuit panel. CONSTITUTION:The circuit panel 29 is made into the construction in which the optical fiber wiring patterns 33 formed of prescribed patterns on the surface of the glass substrate 32 are covered with an insulating layer 34 and connecting pads 37, i.e. the circuit electrodes consisting of the ITO (indium-tin-oxide) layer 36 stacked and formed via the barrier layers 35 on the ends of the electrode wiring patterns 33 are formed in the positions respectively opposite to the above- mentioned counter electrodes 31 on this insulating layer 34. The ITO layers have the high resistance to the electrolytic corrosion by the bleeding out of the electrolyte of the electrochromic display picture elements and, therefore, the durability of the device is improved. The barrier layers improve the adhesive property to the ITO layers.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to electrochromic displays used in display units of various types of equipment.

Conventional technology In general, ECD (electrochromic display) has many advantages, such as vivid colors and high visibility, and when a -degree current is applied to develop colors, the colored state is maintained for a long period of time even when the current is turned off. It is used for stock price presentation boards, etc.

Therefore, a first conventional example of such an ECD will be explained based on FIGS. 5 and 6. First, this ECDl is a substantially rectangular EC pixel (electrochromic display pixel).
2 is formed into a segment type that displays a digital number. Here, these EC pixels 2 are provided with an E layer formed of a flat transparent electrode 4, Wol, etc. under a transparent substrate 3.
It is formed by sequentially stacking an electrolyte layer 6 containing CC50Li or the like, a counter electrode 7, etc. Further, an insulating layer 8 is provided around these laminated films 5 to 7 to insulate each EC pixel 2 from each other. On the other hand, the transparent ff1t44
and the counter electrode 7 are connected to a DC power source 9 whose energizing directions are opposite to each other.
a and 9b are connected via a switch 10.

In such a configuration, by operating the switch 10,
For example, is the transparent electrode 4 facing -? By applying a current that makes the Ii electrode 7 0, the following chemical reaction occurs between the r-, c film 5 and the electrolyte layer 6.

WOj+Li"+e--1 iWo.

Here, WO, is a colorless substance, but it is a product ■
, iWo, indicates blue. In addition, even if the current is turned off after this reaction is completed, LiWO is chemically stable and will not disappear at a certain time. Furthermore, since the reaction described above is a reversible reaction, by applying a current in the opposite direction to that described in 11;I, LiWO is again decomposed into WO1 and [,1, and the color development is eliminated.

In other words, the above-mentioned ECD1 can display a desired digital number by electrically controlling each EC picture #2.

Next, a second conventional example of ECD will be explained based on FIGS. 7 to 9. This ECDll.

A large number of square EC pixels 2a are formed in a dotted pattern. Therefore, the electrical configuration of the drive circuit 12 that controls these EC pixels 2a will be explained based on FIG. 9. A drain electrode 13a of a TFT (thin film transistor)+3 is connected to each EC pixel 2a. Further, the source electrodes 13b of each of the T F "13 are connected in each row and connected to a first pulsed DC power source (not shown). Similarly, the gate electrodes 13c are connected in each row and connected to a first pulse DC power source (not shown). It is connected to a second pulsed DC power source (not shown).

In such a configuration, each TFT 13 responds to the pulse current generated by the first and second pulse DC power sources, for example,
- Controlled sequentially column by column. and.

By synchronizing the pulse currents applied to the source electrode +3b and the gate electrode 13c, a predetermined TFT 13 applies a current to the EC pixel 2a to perform a coloring operation. That is, the EC pixel 2a is turned off.

The desired image will be displayed in a dot matrix display.

Here, although ECDI like the first conventional example is good for displaying a specific image such as the digital number described above, it cannot display any desired image. Further, in the second conventional example ECDII, the EC pixel 2a
However, in this case, the response speed becomes a problem because the number of EC pixels 2a becomes enormous. That is, the EC pixel 2a requires a considerable amount of time from the time when a current is applied until the color development is completed.
Even if the amount of current is increased, approximately 0.5 seconds is required.9 Here, since the image display is scanned row by row, for example, if a matrix screen is formed with 120 rows, the time required to display the screen is is 0.5x120=60 (see), which is not practical since it takes as much as 1 minute to display the image.

Therefore, there is an ECD as disclosed in Japanese Unexamined Patent Publication No. 56-5594, which overcomes these disadvantages.

Therefore, this ECD will be explained as a third conventional example based on FIGS. 10 and 11.

This ECDl 4 is the ECDl 4 exemplified in the second conventional example.
Similar to I, EC pixels 15 are arranged in a matrix. Here, these EC pixels 15 have a frame-shaped sealing member 16 sandwiched between two transparent support plates 17a, 17b, and a counter electrode 18, Display medium 19, supply 1! Electrode 20, display body 2
It is constructed by stacking 1st grade.

Further, the electrical configuration of the drive circuit 22 will be explained based on FIG. 11. First, at one end of each EC pixel 15, a -
A drain electrode 123a of the TFT 23 is connected, and a common counter electrode 24a is connected to the other end. Further, the gate W1 pole 23b of this -th TFT 23 is connected to the second TFT 25.
is connected to the drain electrode 25a of the capacitor 26 and one end of the capacitor 26.

Further, the other end of this capacitor 26 is connected to the first 1'
Together with the source electrode 23c of F T 23, it is connected to a grounded common power supply electrode 24b.

Is the gate electrode 25b of the second TFT 25 in line 11?1? llI41i24c, and the source electrode 25c is connected to the column electrode 124d.

In such a configuration, line? U pole 24c and column electrode 24
A pulse current corresponding to one image to be displayed is applied to d and d. This pulsed current scanning is performed on the capacitor 26 and is completed in an extremely short time. At this time, the -th TFT 23 is electrically connected to the capacitor 26 that has stored electricity.
Is that the only source? II pole 23c and drain electrode 23
A becomes electrically connected. Therefore, the common counter electrode 24
By applying a current between the common supply a and the common supply [1 pole 24b, the current is applied to predetermined EC pixels 15 at the same time. Therefore, each EC pixel 15 starts coloring operation at the same time, and image display is quickly completed.

Problems to be Solved by the Invention Even in the dot matrix type ECD II in which a large number of EC pixels 2a are arranged in a matrix as described above, the drive circuit 22 can be configured with a capacitor 26 and two single-film transistors 23 and 25. Therefore, it is possible to display images in a short time.

Usually, such displays are manufactured by integrally molding display pixels and driving circuits by photoetching or the like. However, the complicated drive circuit 2
It is not easy to integrally manufacture the EC pixel 2 and the EC pixel 2a, making it difficult to manufacture the ECD 14.

On the other hand, in such an ECD 14, there is a demand for a larger display screen and higher density. However, it is difficult to create a large number of drive circuits 22 with complex structures such as multiplexed circuits on one substrate. Furthermore, the need for large-scale manufacturing machines and deterioration of yield rates make it difficult to increase the size and density of ECD14.

Means for Solving the Problems A display panel is provided on the back surface of which pixel electrodes are electrically connected to a large number of electrochromic display pixels formed in a matrix arrangement, and a circuit panel is provided that is integrally joined to this display panel. On the electrode wiring pattern formed on the surface of the circuit panel substrate, circuit electrodes each connected to the pixel electrodes are formed using an indium-thin-oxide layer laminated with a barrier layer interposed therebetween.

By providing a display panel with pixel electrodes formed on the back surface of each of which is electrically connected to a large number of electrochromic display pixels formed in an action matrix arrangement, and providing a circuit panel that is integrally joined to this display panel, it is possible to individually Since the manufactured display panel and circuit panel are bonded together, the productivity of the device is high.Moreover, a circuit panel that is integrally bonded to the display panel is provided, and the electrode wiring pattern formed on the substrate surface of this circuit panel is By forming the circuit electrodes connected to the pixel electrodes using the indium-thin-oxide layer laminated through the barrier layer, the indium-thin-oxide layer formed on the upper layer of the circuit electrode can be used as an electrochromic display pixel. The barrier layer interposed between the electrode wiring pattern and the indium-thin-oxide layer has good adhesion to the electrode wiring pattern due to the characteristics of the material. At the same time, it also has good adhesion to the indium-thin-oxide layer formed in the same vacuum.
The adhesion of the circuit electrode to the electrode wiring pattern is ensured, and the indium thin oxide layer provided on the highly smooth barrier layer is easily peeled off, reducing the etching time for the circuit electrode. Side etching of the oxide layer is reduced and patterning accuracy of circuit electrodes is improved.

Embodiment An embodiment of the unfired Igj will be explained based on FIGS. 1 to 4. Note that the same parts as those described in the conventional example described above are given the same names and numerals, and the description thereof will be omitted. This ECI) 27 has 1 display panel 28 and 11j road panel 29
It has a structure in which these are integrally joined. Therefore, the structure of these terminals 28 and 29 will be explained below.

First, the display panel 28 is shown in FIG.
It has a ↑, M structure, which is almost the same as Dl1, and each EC pixel 30 formed in a matrix forms an EC pixel in the electrolyte layer 6.
The opposite pixel electrode facing I'25? 1li31
are formed by screen printing with carbon paste, resulting in minute protrusions.

On the other hand, in the circuit panel 29, an electrode wiring pattern 33 formed in a predetermined pattern on the surface of a glass substrate 32 is covered with an insulating layer 34, and the counter electrode 31 on this insulating layer 34
I layered on the end of the 1'Ilt electrode wiring pattern 33 with a barrier layer 35 interposed therebetween, in positions facing each other.
The circuit 1 is formed of a layer 36 (Ol indium-syn-oxide) in which connection pads 37 are formed.

Therefore, in this ECD 27, the display panel 28 and the circuit panel 29 are connected to each other in a state where the counter electrode 31 and the connection pad 37 are connected via a conductive adhesive (not shown). Sealing member 38 made of epoxy resin etc.
It is formed by integrally joining.

In such a configuration, the ECD 21 is connected to an external device (not shown) equipped with a DC power supply that can freely switch the polarity of current, an image information output device, etc. to the electrode wiring pattern 33 of the circuit panel 29, and, for example, Current is simultaneously applied to predetermined EC pixels 30 based on the image information latched by this external device, coloring and decoloring of each EC pixel 30 progress simultaneously, and image display by the ECD 27 is quickly completed.

Here, an example of the practical structure and manufacturing method of the circuit panel 29 in this ECD 27 will be described below. first,
An electrode wiring pattern 33 is formed by patterning an aluminum film formed by a sputtering method on the surface of a glass substrate 32 by a photoetching method, and then a plasma CV
A predetermined portion of the insulating layer 34 formed by method D is removed by dry etching to expose the electrode wiring pattern 33. Therefore, on the insulating layer 34 in which the electrode wiring pattern 33 is partially exposed, a barrier layer 35 made of NiCr or the like and a 170 layer 36 are sequentially laminated in the same vacuum using a sputtering method. A connection pad 37 is formed by sequentially etching the substrate and barrier layer 35.

In this ECD 27, a connection pad 37 connected to the EC pixel 30 is connected to a 170 layer 36 which has higher resistance to electric field corrosion due to seepage of the electrolyte layer 6 of the EC pixel 30 than metal electrodes 33, 35, etc. The device has high durability because it is formed on the upper layer.

Furthermore, in this ECD 27, the barrier layer 35 is interposed between the electrode wiring pattern 33 and the 170 layer 36, thereby ensuring the adhesion of the connection pad 37 to the electrode wiring pattern 33. In other words, the 170 layer 36 and the barrier layer 35 can be sputtered in the same vacuum, so they have good adhesion, and the barrier layer 35 made of NiC:r and the electrode wiring pattern 33 made of AQ are made of metal, respectively. This takes advantage of the fact that it has good adhesion.

Furthermore, since the 170 layer 36 is provided on the highly smooth barrier layer 35, it can be easily peeled off, so the etching time for the connection pad 37 is shortened.
Since side etching is reduced, the patterning accuracy of the connection pads 37 is improved, which contributes to higher density of the 1.]C pixels 30 and miniaturization of the CD 27.

Note that the barrier layer 35 mentioned here has good adhesion to the electrode wiring pattern 33 even if it is not formed in the same vacuum, has high conductivity, and has a good surface smoothness during formation.
The 0 layer 36 can be easily etched, and the 11' 0 layer 36 is made of a material that satisfies conditions such as being insoluble in the etching solution or having an extremely slow etching rate, such as N.
In addition to i C'' and r, Cr or the like can be used.

Effects of the Invention As described above, the present invention provides a display panel in which pixel fa poles are formed on the back surface, each of which is electrically connected to a large number of electrochromic display pixels formed in a matrix arrangement, and is integrated with this display panel. By providing a circuit panel that is bonded to the circuit panel, the productivity of the device is high because the individually manufactured display panel and the circuit panel are bonded, and large-screen electrochromic displays can be manufactured without the need for large manufacturing machines. A circuit panel that can be manufactured with high productivity and is integrally bonded to a display panel is provided, and indium is laminated via a barrier layer on the electrode wiring pattern formed on the surface of the circuit panel substrate. - By forming the circuit electrodes connected to the pixel electrodes with a thin oxide layer, the indium thin oxide layer formed on the upper layer of the circuit electrodes has a high resistance to electric field corrosion caused by seepage of electrolyte of the electrochromic display pixel. The barrier layer interposed between the electrode wiring pattern and the indium-thin-oxide layer has good adhesion to the electrode wiring pattern due to the characteristics of the material. At the same time, it also has good adhesion to the indium-thin-oxide layer formed in the same vacuum, ensuring the adhesion of the circuit electrode to the electrode wiring pattern, resulting in high reliability of the device, and a highly smooth barrier. The indium-thin-oxide layer provided on the layer has good peeling properties, which shortens the etching time of the circuit electrode, reduces side etching of the indium-thin-oxide layer, improves the patterning accuracy of the circuit electrode, and improves the patterning accuracy of the circuit electrode. This has effects such as contributing to higher density of chromic display pixels and miniaturization of devices.

27... Electrochromic display, 28.
... Display panel, 29... Circuit panel, 3o... Electrochromic display pixel, 31... Pixel electrode, 3
2... Substrate, 33... Electrode wiring pattern, 35...
・Barrier layer, 36... Indium-syn-oxide layer, 37... Circuit electrode

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an embodiment of the present invention, Fig. 2 is a perspective view of a circuit panel, Fig. 3 is an explanatory diagram of the manufacturing process, Fig. 4 is a vertical side view of the circuit panel, and Fig. 5 is FIG. 6 is a perspective view showing the first conventional example, FIG. 6 is a vertical side view, FIG. 7 is a plan view showing the second conventional example, FIG. 8 is a vertical side view, FIG. 9 is a circuit diagram,
FIG. 0 is a longitudinal sectional side view showing a third conventional example, and FIG. 11 is a circuit diagram.

Claims (1)

[Claims] A display panel is provided on the back surface of which is formed a pixel electrode that is electrically connected to a large number of electrochromic display pixels formed in a matrix arrangement, a circuit panel is provided that is integrally joined to this display panel, and the substrate surface of this circuit panel is provided. An electrochromic display characterized in that circuit electrodes each connected to the pixel electrodes are formed by an indium-synoxide layer laminated on the electrode wiring pattern formed on the electrode wiring pattern with a barrier layer interposed therebetween.