JPH03231231A - Electrochromic display - Google Patents

Abstract

PURPOSE:To reduce the magnetic flux density of a driving circuit and to relatively increase the density of image elements for electrochromic display by dividedly forming the circuit connecting parts of an electrode wiring pattern at both edges of the rectangular substrate of a circuit panel. CONSTITUTION:An electrode wiring pattern 33 is formed in a prescribed shape on the surface of a rectangular substrate 32, an insulating layer 34 is formed so as to coat the pattern 33 and electrode pads 35 as circuit electrodes are formed on the layer 34 at positions corresponding to counter electrodes 31. The pads 35 are connected to the pattern 33 through pierced through holes in the layer 34 and connecting terminals 37 as the circuit connecting parts of the pattern 33 are dividedly formed at both ends of the substrate 32 to obtain a circuit panel 29. Since the wiring density of the electrode wiring pattern can be reduced by simple structure, the magnetic flux density of a driving circuit can be reduced and the density of image elements for electrochromic display can be relatively increased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electrochromic display used as a display section of various types of equipment.

Conventional technology In general, ECDs (electrochromic displays) have many advantages, such as vivid colors and high visibility, and when a certain amount of 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. 9 and 10. 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 formed by sequentially laminating, under a transparent substrate 3, a flat transparent electrode 4, an electrolyte layer 6 containing ECC50Li made of WOl, etc., 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 electrode 4 and the counter electrode 7 are provided with a DC power source 9a whose current direction is opposite to each other;
9b is connected via a changeover switch IO.

In such a configuration, by operating the changeover switch 10, for example, by applying a current such that the transparent electrode 4 is negative and the counter electrode 7 is positive, the ECC50 electrolyte layer 6 causes the following chemical reaction.

W　O, +　L　i++　e-=　L　i　W　O.

Here, WO8 is a colorless substance, but the product L
iWO9 shows blue color. Furthermore, even if the current is turned off after this reaction is completed, L 1WOa is chemically stable and does not disappear in a short period of time. Furthermore, since the above chemical reaction is a reversible reaction, by applying a current in the opposite direction to the above,
LiWO, is again decomposed into WO, and Li, and the coloring is eliminated.

That is, the above-mentioned ECD1 can display a desired digital number by electrically controlling each EC pixel 2.

Next, the second conventional example of ECD is shown in Figures 11 to 13.
This will be explained based on the diagram. This ECDII has a large number of square EC pixels 2a formed in a dot matrix shape. Therefore, the electrical configuration of the drive circuit 12 that controls these EC pixels 2a will be explained based on FIG. 13. Each EC pixel 2a has a TFT (thin film transistor) 13
The drain electrode 13a of is connected to the drain electrode 13a. Further, the source electrodes 13b of each TFT 13 are connected in each row and connected to a first pulsed DC power source (not shown), and the gate electrodes 13c are connected in each column and connected to a second pulsed DC power source (not shown). )It is connected to the.

In such a configuration, each TFT 13 is sequentially controlled, for example, for each -column, in response to the pulse current generated by the first and second pulsed DC power supplies. And source electrode 13b
By synchronizing the pulse currents applied to the EC pixel 2a and the gate electrode 13c, a predetermined TFT 13 transmits the current to the EC pixel 2a.
The coloring operation is performed by applying That is, the desired image is displayed in a dot matrix display in which the EC pixel 2a is one dot.

Here, the ECD1 like the first conventional example is good for displaying a specific image such as the above-mentioned digital number, but cannot display any desired image. Furthermore, in the second conventional example ECDll, the EC pixel 2a
However, in this case, the response speed becomes a problem because the number of EC pixels 2a becomes enormous. In other words, since the EC pixel 2a does not have a threshold value for driving power, it is necessary to continue applying current until color development or decolorization is completed. It takes about 0.5 seconds. Here, scanning of the image display is performed row by row, so
For example, when a matrix screen is formed with 120 columns, the time required to display the screen is 0.5×120=60 (sec), which is not practical because 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. 14 and 15.

This ECD14 is the same as the ECD14 illustrated in the second conventional example.
Similarly, the 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 and 17b, and a gap between these support plates 17a and 17b, which are opposite to each other. It is constructed by laminating an electrode 18, a display medium 19, a power supply electrode 20, a display body 21, etc.

Further, the electrical configuration of the drive circuit 22 will be explained based on FIG. 15. First, at one end of each EC pixel 15, a -
A drain electrode 23a of the TFT 23 is connected to the TFT 23, and a common facing type fI7124a is connected to the other end. Also,
The gate electrode 23b of this -th TFT 23 is connected to the second TFT 23.
25 and one end of a capacitor 26.

Furthermore, the other end of this capacitor 26 is connected to the -th TFT.
It is connected to a grounded common power supply electrode 24b together with the source electrode 23c of No. 23.

On the other hand, the gate electrode 25b of the second TFT 25 is connected to the row electrode 2.
4c, and the source electrode 25c is connected to the column electrode 24d.

In such a configuration, the row electrode 24c and the column electrode 24d
Then, a pulse current corresponding to the image to be displayed is applied. This pulsed current scanning is performed on the capacitor 26 and is completed in an extremely short time. At this time, only the -th TFT 23 that is electrically connected to the capacitor 26 that has stored electricity has its source 1m23c and drain electrode 23a electrically electrically connected. Therefore, by applying a current between the common opposing electrode 24a and the common feeding electrode 24b,
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 As mentioned above, even in the dot matrix type ECD 14 in which a large number of EC pixels 15 are arranged in a matrix, the drive circuit 22 is formed by the capacitor 26 and two thin film transistors 23 and 25. By performing switching for each Ec pixel 15, it is possible to display an image in a short time. Usually, such displays are manufactured by integrally molding display pixels and driving circuits by photoetching or the like. However, it is not easy to integrally manufacture the complicated driving circuit 22 and the EC pixel 2a as described above, making it difficult to manufacture the ECD 14. Also,
For the above-mentioned ECD 14 and the like, there is also a demand for larger display screens and higher density display pixels. So, for example,
Although it is envisaged that the number of EC pixels 2a formed by increasing the size of the support plate 17 will be increased, it is difficult to form the drive circuit 22 with a complicated structure in high density as described above.
It is also necessary to increase the size of manufacturing equipment, resulting in a decrease in productivity.

Therefore, the present applicant's proposal is to manufacture a display panel in which EC pixels are arranged in a matrix and a circuit panel in which a drive circuit is formed separately and join them together, thereby making it possible to
JP-A-1-289920 discloses a method with improved productivity. Furthermore, the applicant has formed only the wiring that connects each EC pixel to an external circuit on the circuit panel, and formed the terminal part of this wiring on one edge of the circuit panel board, thereby simplifying the connection of the circuit. We proposed an ECD with a larger display screen in Japanese Patent Application No. 1-7323.

Currently, there is a demand for further development of larger ECD display screens, higher display pixel density, and improved productivity.

Means for Solving the Problem The invention according to claim 1 provides a display panel in which a large number of electrochromic display pixels are formed in a matrix, and a pixel electrode that is electrically connected to each of the electrochromic display pixels is formed on the back surface. A circuit panel is provided on the surface of which a circuit electrode is formed to be connected to each pixel electrode of the front panel, and an electrode wiring pattern is formed to connect at least the circuit electrode and the drive circuit, and the circuit panel and the display are provided. In an electrochromic display that is integrally joined to a panel, the circuit connection portions of the electrode wiring pattern are distributed and formed on both edges of a rectangular substrate of the circuit panel.

The invention according to claim 2 provides a method for connecting an electrode wiring pattern formed on a substrate of a circuit panel and a circuit electrode formed on the electrode wiring pattern via an insulating layer through a through hole formed in the insulating layer. did.

The invention according to claim 1 can reduce the wiring density of the electrode wiring pattern with a simple structure by forming the circuit connection parts of the electrode wiring pattern on both edges of the rectangular substrate of the circuit panel. Therefore, it is possible to lower the magnetic flux density of the drive circuit and relatively increase the density of electrochromic display pixels.

Furthermore, the invention according to claim 2 provides an arrangement for connecting the electrode wiring pattern formed on the substrate of the circuit panel and the circuit electrode formed on the electrode wiring pattern with an insulating layer interposed therebetween, through a through hole formed in the insulating layer. By connecting the electrode wiring pattern and circuit 1! Each pole can be formed into a suitable shape without considering the other.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 to 8. Incidentally, the same parts as those explained in the above-mentioned conventional example will be given the same names and symbols, and the explanation will be omitted. This E
The CD 27 has a structure in which a display panel 28 and a circuit panel 29 are integrally joined. Therefore, the structure of these panels 28 and 29 will be explained below.

First, the display panel 28 is constructed by forming an ITO film as a transparent electrode on a transparent substrate, as shown in FIG.
It has almost the same structure as CDII etc., and the 5th [! As illustrated in FIG.
The counter electrode 31, which is a pixel electrode facing C50, is formed by screen printing of carbon paste and protrudes minutely.

On the other hand, the circuit panel 29 is formed in a predetermined shape on the surface of a rectangular substrate 32. An insulating layer 34 is formed to cover the polar wiring pattern 33, and an electrode pad 35, which is a circuit electrode, is formed on this insulating layer 34 at a position facing the counter electrode 31.

As illustrated in FIG. 2, these electrode pads 35 are connected to through holes 3 formed in the insulating layer 34.
6 to the electrode wiring patterns 33, and as illustrated in FIG. It is formed.

Therefore, in this ECD 27, with the counter electrode 31 and the electrode pad 35 connected via a conductive adhesive 38, the display panel 28 and the circuit panel 29 are connected to a sealing member (made of epoxy resin or the like). (not shown) has an integrally joined structure.

In this ECD 27, a drive circuit board 41 on which a drive IC 39, which is a drive circuit for each EC pixel 30, is mounted on an elongated board 40 is attached to the back surface of the circuit panel 29, and a drive circuit board 41 is mounted on the back surface of the circuit panel 29. The connection terminal 43 formed together with the wiring 42 is an F PC (Flexible PC).
It is connected to the connection terminal 37 of the circuit panel 29 by a terminal 44.

In such a configuration, the ECD 27 is connected to the display panel 28, for example, as shown in the equivalent circuit shown in FIG.
With DC power supplies 9a and 9b whose current polarity can be freely switched connected to the commonly connected transparent electrode 4 of all EC pixels 30, predetermined image information is transmitted to the drive IC 39 of the drive circuit board 41.
to latch.

Therefore, by operating the changeover switch 10 connected to the DC power supplies 9a and 9b while the image information is latched to the switching element in the drive IC 39, current is simultaneously applied to predetermined EC pixels 30. Coloring and decoloring of the EC pixels 30 proceed simultaneously, and the image display by the ECD 27 is quickly performed.

Here, an example of a practical method for manufacturing the circuit panel 29 in this ECD 27 will be described below.

First, an aluminum film is formed on the surface of the cleaned substrate 32 by a sputtering method and patterned by a photoetching method to form an electrode wiring pattern 33. Then, a photosensitive polyimide is applied thereon and prebaked, and then exposed and developed in a predetermined pattern and cured by heating to form an insulating layer 34 having through holes 36. Further, a Ti film is formed on this insulating layer 34 by sputtering and patterned by photoetching to form electrode pads 35 connected to electrode wiring patterns 33 through through holes 36, respectively.

Note that in the ECD 27 exemplified in the above manufacturing method, Ti is used as the material for the electrode pad 35, but by doing so, electric field corrosion of the electrode pad 35 due to outflow of electrolyte ions from the electrolyte layer 6 of the EC pixel 30 can be prevented. It can be prevented.

As illustrated in FIG. 1, this ECD 27
The connection terminals 37 of the electrode wiring patterns 33 connected to each EC pixel 30 are formed on both edges of the substrate 32 of the circuit panel 29, so these electrode wiring patterns 33 are connected to one edge of the substrate 32. The formation density is lower than that in the case of formation. Therefore, in this ECD 27, the electrode wiring pattern 33 can be easily formed and the EC pixels 30 can be densely arranged, so that the productivity and image quality of the device can be improved. Moreover, since the EC pixels 30 need to be switched individually, the number of drive ICs 39 tends to increase, which increases their packaging density and tends to impede productivity. However, since the connection terminals 37 of this ECD 27 are located at both edges of the circuit panel 29, the drive circuit board 41 is divided into both sides of the device, reducing the mounting density of the drive ICs 39 and improving productivity. There is.

In addition, in this ECD27, as illustrated in FIG.
Since the electrode pads 35 of the circuit panel 29 are connected to the electrode wiring patterns 33 through the through holes 36 of the insulating layer 34, these electrode wiring patterns 33 can be easily formed without considering the shape of the electrode pads 35. Therefore, the electrode pad 35 can be formed into a shape that allows good connection with the counter electrode 31 of the display panel 28 without considering the shape of the electrode wiring pattern 33. Therefore, the productivity and image quality of the device can be further improved.

In addition, in the ECD 27 illustrated in FIG. 1 etc., the EC pixel 3
0's are arranged in 8 vertical lines, but when manufacturing an actual product, it is assumed that each character will be displayed in a dot matrix such as +6x16. In this case, as illustrated in FIG. 7, if the ECD 27 has a pixel pitch of 2.5 (mm) and can display four characters in two rows, the circuit panel 29 will have a pixel pitch of 2.5 (mm).
Since 16 electrode wiring patterns 33 are formed with a width of mm), the wiring pitch of these electrode wiring patterns 33 is 2.5 (nvn)/I'6 = 156 (μm).
It is. Therefore, for example, the ratio of the wiring width to the wiring spacing should be set to 1.
= 1, the width of the electrode wiring pattern 33 is approximately 80 (μ
m), which can be easily manufactured using existing thin film technology.

Next, electrode wiring pattern 3 produced as described above.
Estimate the resistance value of 3. The electrode wiring pattern 33 has the longest distance from the electrode pad 35 to the connection terminal 37 and has a length α of approximately 40 (mm) (=16×2.5), which is an aluminum wire with a thickness of 1.0 (μm). If it is formed of a film, the sheet resistance Rc is 0.03Ω, so the width W is 8
If it is 0 (μm), the wiring resistance R is R= RcX Q /
w = 0.03 x 4010.08 = 15 (Ω). Here, since the resistance value of the EC pixel 30 is approximately Ω, it is obvious that the tS wiring pattern 33 having the above-mentioned resistance value does not impede the performance of the device.

Furthermore, the present applicant actually manufactured an electrode wiring pattern 33 having the above-mentioned dimensions on the substrate 32, and applied it to the existing FP.
When connecting to the drive circuit using C44, it was confirmed that the connection could be easily realized without any short circuits or the like.

For example, if the electrode wiring pattern 33 is formed on one edge of the substrate 32, the wiring density will be twice that of the above-mentioned rough example, and the pitch of the connection terminals 37 will be approximately 12.5 (lines/mm). With this technology, wiring is difficult even with wire bonding methods.

In addition, in the 20ECD27, the drive IC 39 which is the drive circuit of the display panel 28 is provided on the drive circuit board 41 separate from the circuit panel 29, but the present invention is not limited to the above structure. , as illustrated in FIG. 8, an EC in which a drive IC 48 as a drive circuit is mounted on a circuit connection portion 47 of an electrode wiring pattern 46 of a circuit panel 45.
D49 etc. can also be implemented.

Effects of the Invention The invention described in claim 1 provides a display panel in which a large number of electrochromic display pixels are formed in a matrix, and a pixel electrode that is electrically connected to each of the electrochromic display pixels is formed on the back surface, and this front panel A circuit panel is provided on the surface of which a circuit electrode is formed to be connected to each of the pixel electrodes, and an electrode wiring pattern is formed to connect at least the circuit electrode and the drive circuit, and the circuit panel and the display panel are integrated. In the electrochromic display, which is bonded to the electrochromic display, the circuit connection parts of the electrode wiring pattern are distributed and formed on both edges of the rectangular board of the circuit panel, which reduces the wiring density of the electrode wiring pattern with a simple structure. Therefore, it is possible to reduce the magnetic flux density of the drive circuit and relatively increase the density of electrochromic display pixels, which can contribute to improving device productivity and image quality. The invention as set forth in claim 2 provides a method for connecting an electrode wiring pattern formed on a substrate of a circuit panel and a circuit electrode formed on the electrode wiring pattern via an insulating layer through a through hole formed in the insulating layer. By connecting, the electrode wiring pattern and the circuit electrode can each be formed into a good shape without considering the other, contributing to higher density of electrochromic display pixels and improved device productivity. It has the following effects:

[Brief explanation of drawings]

Fig. 1 is a plan view showing an embodiment of the present invention, Fig. 2 is a longitudinal sectional side view of main parts, Fig. 3 is an overall perspective view, Figs. 4 and 5 are longitudinal sectional front views, and Fig. 6 is A circuit diagram of the equivalent circuit, FIG. 7 is an explanatory diagram of the usage state, FIG. 8 is a perspective view of a modified example, FIG. 9 is a perspective view showing the first conventional example, FIG.
Figure 1 is a plan view showing the second conventional example, Figure 12 is a vertical side view, Figure 13 is a circuit diagram, Figure 14 is a vertical side view showing the third conventional example, and Figure 15 is a circuit diagram. be. 27.49...electrochromic display,
28...Display panel, 29.45...Circuit panel,
30... Electrochromic display pixel, 31...
Pixel 1i pole, 32... Substrate, 33.46... Electrode wiring pattern, 34... Insulating layer, 35... Circuit electrode,
36...Through hole, 37.47...Circuit connection part, 39,48...Drive circuit ``71Z Country (Kitou)'' 3.15 Low weight, 1. .

Claims (1)

[Scope of Claims] 1. A display panel is provided in which a large number of electrochromic display pixels are formed in a matrix and a pixel electrode is formed on the back surface of the electrochromic display pixel and is electrically connected to each of the electrochromic display pixels. A circuit panel is provided, in which a circuit electrode connected to each of the pixel electrodes is formed on the surface thereof, and an electrode wiring pattern connecting at least the circuit electrode and a drive circuit is formed, and this circuit panel and the display panel are integrated. 1. An electrochromic display in which circuit connection portions of the electrode wiring pattern are distributed and formed on both edges of a rectangular substrate of the circuit panel. 2. The electrode wiring pattern formed on the substrate of the circuit panel and the circuit electrode formed on the electrode wiring pattern via an insulating layer are connected via a through hole formed in the insulating layer. The electrochromic display according to claim 1.