JP2000187232A - Electrode substrate for display panel and manufacture of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode substrate for display panels, which uniformly ensures good electrical conductivity to a transparent electrode and an auxiliary electrode, while adequately maintaining the thickness and the numerical aperture of the auxiliary electrode and the wiring resistance of the transparent electrode by devising an plan in the formation of a burried auxiliary electrode structure, and a manufacturing method therefor. SOLUTION: In a glass paste film forming process S30 or a transparent electrode forming processes S70, a photosensitive lead glass paste is formed into a film on the inner surface of the transparent substrate 11 and is temporarily calcined as a glass paste film (b), so as to be thicker than each auxiliary electrode 12, and the glass paste film (b) is formed as plural stripe-like glass paste film parts (c) by the patterning treatment. At this time, a gap G between each opposed side face of the auxiliary electrode 12 and the glass paste film parts (c) is formed in a grooved shape. Thereafter, each glass paste film part (c) is subjected to regular calcination, and each glass paste film part (c) is once burried into each gap G by smelting to be formed as each flattened film 13. Then plural strip-like transparent electrodes 14 are formed of ITO(indium tin oxide).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode substrate for various display panels such as a liquid crystal panel and an electroluminescence panel, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, for example, in a matrix drive type transmissive liquid crystal panel, a conventional notebook personal computer having a diagonal size of 10 inches to 13 inches has been changed to a C-type.
The size of liquid crystal panels having a diagonal of 15 inches to a diagonal of 21 inches for RT replacement is shifting to a larger size. In addition, diagonal 20
Expectations for wall-mounted televisions ranging from inches to 40 inches diagonally are also increasing.

Along with these, the wiring resistance of each of the plurality of transparent electrodes on the electrode substrate of the liquid crystal panel increases, and a large problem emerges that the increase in the wiring resistance causes the waveform of the voltage applied to the transparent electrode to become dull. I have. The dullness of the applied voltage waveform causes crosstalk on the display screen of the liquid crystal panel and causes unevenness in display luminance, thereby significantly reducing display quality.

For example, in the case of a large liquid crystal panel having a diagonal of about 17 inches, if an antiferroelectric liquid crystal is used,
The wiring resistance required for the transparent electrode is as follows:
In the case of having a length of about 0 μm and a length of about 300 mm, in order to prevent dullness in the voltage waveform applied to the transparent electrode,
It is as low as about 100 (Ω). At present, even a transparent electrode having the lowest resistance (thickness: 300 nm, sheet resistance: 4 (Ω / □)) has a wiring resistance of about 3 (kΩ), which does not satisfy the above requirements at all.

On the other hand, even if an attempt is made to reduce the wiring resistance by increasing the thickness of the transparent electrode, it is necessary to increase the thickness to 30 times, which is practically impossible. On the other hand, an electrode substrate having a stacked auxiliary electrode structure using an auxiliary electrode as a transparent electrode has been proposed. This electrode substrate is shown in FIGS. 7A to 7F.
It is formed according to each process as shown by.

First, in an ITO film forming step S1, ITO, which is a material for forming a transparent electrode, is deposited on a glass substrate 1 for 300 minutes.
(Nm) to form a film by sputtering (see reference numeral 2 in FIG. 7A). Next, in a photo patterning step S2, the ITO film is patterned on the plurality of transparent electrodes 2a by photolithography. Thereafter, in a metal film forming step S3, a metal (Cu, Al, or the like) as a material for forming the auxiliary electrode is formed by sputtering (see reference numeral 3 in FIG. 7C). Then, in the metal patterning step S4, this film formation 3 is patterned by a photolithography method into a plurality of transparent electrodes 3a having a line width of about 50 (μm).

Next, in an insulating film forming step S5, the insulating film is formed by sputtering tantalum oxide (FIG. 7E).
Then, polyimide is printed on the insulating film 4 by an offset printing method to form an alignment film 5. Thus, the formation of the electrode substrate is completed.

[0008]

However, in the electrode substrate having the stacked auxiliary electrode structure formed as described above, since the auxiliary electrode 2a blocks light transmitted through the electrode substrate, the transmittance of the liquid crystal panel is reduced. Would. For example, the width 2 is applied to a 300 × 100 (μm) pixel constituting a transparent electrode.
When an auxiliary electrode of 0 (μm) is provided, the aperture ratio is reduced to 75%. When an auxiliary electrode having a width of 60 (μm) is provided in the pixel, the aperture ratio is reduced to 50%. The above aperture ratio is
When light is transmitted effectively, it is defined by (light transmission area / pixel area).

Therefore, when a liquid crystal panel is designed with a wiring electrode width of 20 (μm) that can secure a high aperture ratio, Cu, which is one of the lowest-resistance metals, is used as a material of the auxiliary electrode.
Is used, the thickness of the auxiliary electrode becomes 4 (μm). The distance between the two electrode substrates of the liquid crystal panel is determined by the STN method or the T
In an FT type liquid crystal panel, the thickness is 4 to 5 (μm). In a liquid crystal panel using an antiferroelectric liquid crystal or a ferroelectric liquid crystal,
It is about 2 (μm).

Therefore, it is impossible to provide such a thick auxiliary electrode in a liquid crystal panel using an antiferroelectric liquid crystal or a ferroelectric liquid crystal, and even in an STN type or a TFT type liquid crystal panel. In addition, the distance between the auxiliary electrode and the opposing electrode substrate is small, which causes a short circuit in the wiring between the two electrode substrates. When the thickness of the auxiliary electrode is increased as described above, a step is generated on the inner surface (alignment film) of the electrode substrate, and the alignment of the liquid crystal is disturbed. Further, if a step occurs even in the insulating film provided for preventing short circuit between the two electrode substrates, a short circuit between the two electrode substrates is caused.

In consideration of the above, it is necessary to suppress the thickness of the auxiliary electrode to about 0.5 μm. If an attempt is made to achieve 100 Ω with this film thickness, the width of the auxiliary electrode will be 200 μm, and the aperture ratio will be greatly reduced to 25%. In contrast to the above, Japanese Patent Application Laid-Open No. 9-899
An electrode substrate adopting an embedded electrode structure in which each auxiliary electrode is buried in a glass substrate of the electrode substrate as described in Japanese Patent Publication No. 17 and a corresponding transparent electrode is formed thereon is proposed.

However, in the electrode substrate having the embedded electrode structure, a resin is interposed between the surface of the glass substrate on which the auxiliary electrode is formed and the surface of the template, and the glass substrate and the template are pressed by a roller to form the electrode substrate. And the template, and then
It is formed by curing the resin and then peeling off only the template.
For this reason, in such a formation process, the resin is likely to partially adhere on the auxiliary electrode, and the connection between the ITO to be formed later and the auxiliary electrode is partially defective. Therefore, the wiring resistance of the transparent electrode patterned and formed from the ITO film becomes uneven, and as a result, a problem occurs that the display becomes uneven on the liquid crystal panel.

In order to cope with the above, the present invention devises a method of forming a buried auxiliary electrode structure, and appropriately maintains the thickness of the auxiliary electrode, the aperture ratio, and the wiring resistance of the transparent electrode. It is another object of the present invention to provide an electrode substrate for a display panel and a method for manufacturing the same, which uniformly secure good conductivity between the transparent electrode and the auxiliary electrode.

[0014]

According to the first, second and fifth aspects of the present invention, in the auxiliary electrode forming step (S10, S20), the metal on the inner surface of the substrate (11) is formed. A plurality of stripe-shaped auxiliary electrodes (12) are formed of a material, and in a material film forming step (S30), a low melting point flattening film forming material is applied to the inner surface of the substrate so as to embed each auxiliary electrode, thereby forming a material film. Form.

Then, a patterning process step (S40)
, The material film is patterned so as to form groove-shaped gaps on both sides in the width direction of each auxiliary electrode, and in the material film firing step (S50), the material film patterned in the patterning process is melted by firing. Then, each gap is filled and a part of the low melting point flattening film forming material is absorbed by each auxiliary electrode so as to expose the tip end surface of each auxiliary electrode, and each flattening film (13) is formed. In the main electrode forming step (S60, S70), a stripe-shaped main electrode (14) is formed on the distal end surface of each auxiliary electrode along the longitudinal direction.

According to this, the material film is melted by the sintering and flattened while filling the groove-shaped gaps formed on both sides in the width direction of each auxiliary electrode so as to expose the tip end surface of each auxiliary electrode. Therefore, even if a stripe-shaped main electrode is formed on the tip surface of each auxiliary electrode along its longitudinal direction,
Each main electrode is directly and uniformly adhered to the tip surface of each auxiliary electrode.
As a result, the conductivity between the main electrode and the auxiliary electrode can be favorably secured over the entirety.

Here, as in the invention described in claim 2,
A photosensitive silver paste may be used as a metal material in the auxiliary electrode forming step, and a photosensitive lead glass paste may be used as a low melting point flattening film forming material in the material film forming step.
According to the third, fourth, fifth and sixth aspects of the present invention, in the auxiliary electrode forming step (S10, S20), the substrate (1
A plurality of stripe-shaped auxiliary electrodes (12) are formed from a porous metal material on the inner surface of 1), and a material film forming step (S3) is performed.
In 0), a material film is formed by applying a low melting point flattening film forming material to the inner surface of the substrate so as to bury each auxiliary electrode.

Then, in the material film firing step (S100), the material film is melted by firing, and a film portion of the molten material film corresponding to the leading end surface of each auxiliary electrode is absorbed by each auxiliary electrode, and Each flattening film (13) is formed so as to expose the front end face, and a main electrode forming step (S
60, S70), a stripe-shaped main electrode (14) is formed on the tip surface of each auxiliary electrode along its longitudinal direction.

According to this, the material film is melted by firing, and is absorbed by the auxiliary electrode at a film portion corresponding to the front end surface of each auxiliary electrode, so that each flat surface is exposed. It is formed as an oxide film (13). As a result, substantially the same functions and effects as the first aspect of the invention can be achieved. Here, as in the invention described in claim 4,
A photosensitive silver paste may be used as the porous metal material in the auxiliary electrode forming step, and a lead glass paste may be used as the low melting point flattening film forming material in the material film forming step.

According to the fifth aspect of the present invention, in the material film baking step, the flattening film is formed in a tapered shape on both sides (13a) in the width direction of each auxiliary electrode on the surface. Thereby, even if the main electrode forming material is formed on each auxiliary electrode and each flattening film before forming each main electrode, this film formation is performed on both sides of the tapered width direction of each flattening film and each flattening film. It is made smoothly over the tip surface of the auxiliary electrode. Therefore, the occurrence of the step disconnection of the film formation can be reliably prevented.

Further, as in the invention according to claim 6, a part of the low melting point flattening film forming material is absorbed by each auxiliary electrode in the material film baking step, so that each of the materials present between the respective auxiliary electrodes is formed. The flattening film is in a concave state toward the substrate side, and between the material film baking step and the main electrode forming step, each flattening film in the concave state is used to eliminate the concave state. A polishing step of polishing each auxiliary electrode and each planarization film including the top of each protruding auxiliary electrode may be provided.

According to the seventh aspect of the present invention, the display panel electrode substrate comprises an auxiliary electrode (12) and a flattening film (22) which are alternately formed in stripes on the inner surface of the substrate (11). 13), and a main electrode (14) formed in a stripe shape along the longitudinal direction on the tip surface (12a) of each auxiliary electrode. Here, the material constituting the flattening film is mixed in each auxiliary electrode.

This also makes it possible to provide a display panel electrode substrate suitable for achieving the functions and effects of the first to fifth aspects of the present invention. According to the invention described in claim 8, in the invention described in claim 7, both sides (13a) in the width direction of each auxiliary electrode in the surface of each flattening film are formed in a tapered shape.

This makes it possible to provide an electrode substrate for a display panel suitable for achieving the functions and effects of the invention described in claim 7.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows an example in which the present invention is applied to a liquid crystal panel which is one embodiment of a display panel.

This liquid crystal panel comprises a lower electrode substrate 10,
And an upper electrode substrate 20.
Between 0 and 20, a smectic liquid crystal is provided with a plurality of spacers via a band-shaped seal. In addition,
The lower electrode substrate 10 is a scanning electrode electrode substrate, and the upper electrode substrate 20 is a signal electrode side electrode substrate. Lower electrode substrate 1
Numeral 0 denotes a plurality of opaque stripe-shaped auxiliary electrodes 12, a plurality of transparent stripe-shaped planarization films 13, a plurality of stripe-shaped transparent electrodes 14, a transparent insulating film and a transparent alignment film on the inner surface of the transparent substrate 11 in order. It is formed and formed.

Here, the transparent substrate 11 is formed of a glass plate having a thickness of about 1 mm made of a soda-lime glass material or the like. It is desirable that both surfaces of the glass plate 11 have high parallelism by polishing. Each auxiliary electrode 12 and each flattening film 13 are formed alternately and in parallel with each other on the inner surface of the transparent substrate 11, and each auxiliary electrode 12 has a tip end surface as illustrated in FIG. At a certain exposed surface 12a, it is uniformly in close contact with the back surface of the corresponding transparent electrode 14. Thereby, each auxiliary electrode 12 lowers the wiring resistance value of the corresponding transparent electrode 14. In the present embodiment, the forming material of each auxiliary electrode 12 is a metal material,
It is desirable to have a low resistance value and good adhesion to the glass plate as the transparent substrate 11.

Each of the flattening films 13 has the same height as the height of each of the auxiliary electrodes 12 from the inner surface of the transparent substrate 11. A transparent photosensitive lead glass paste having a melting point is used. Each transparent electrode 14 is formed on the exposed surface 12a of each corresponding auxiliary electrode 12 along its longitudinal direction. In addition,
As a material for forming each transparent electrode 14, ITO or ZnO can be adopted.

On the other hand, the upper electrode substrate 20 is
A plurality of stripe-shaped transparent electrodes 22, a transparent insulating film and an alignment film are sequentially formed on the inner surface of the substrate. In addition,
The plurality of transparent electrodes 25 are arranged so as to extend at a right angle to the plurality of transparent electrodes 12, and form a plurality of matrix-shaped pixels together with the smectic liquid crystal. Next, a method of manufacturing the lower electrode substrate 10 of the liquid crystal panel configured as described above will be described with reference to FIG.

FIG. 2A shows an auxiliary electrode material forming step S10.
Is shown. In this step, the photosensitive silver paste is applied as shown in FIG.
As shown by the symbol a in (a), a silver paste film is formed on the entire inner surface of the transparent substrate 11 by application by a printing method. The thickness of the silver paste film is set to a thickness required for reducing the wiring resistance of each transparent electrode 14 after the main firing of the film, for example, about 10 μm. After the above film formation,
The silver paste film a is pre-baked at a temperature of 80 ° C. and dried.

In this embodiment, the photosensitive silver paste comprises 65% by weight of an inorganic component, 34.5% by weight of an organic component, and 0.5% by weight of a PbO component. Here, the inorganic component is composed of 60% by weight of silver and 5% by weight of Bi-Pb.
-Si-based glass. Further, the inorganic component is a mixed component comprising an acrylic resin, a monomer, a photoinitiator, and an organic solvent.

Next, an auxiliary electrode forming step S20 (FIG. 2)
(B)), the silver paste film a is developed and exposed by a photolithography method and is patterned,
Main firing is performed at 0 ° C. to form a plurality of stripe-shaped auxiliary electrodes 12. The silver paste film a was 5 μm
shrink to a film thickness of m. Next glass paste film forming step S
30 (see FIG. 2 (c)), a transparent photosensitive lead glass paste which is a planarizing material is denoted by a symbol b in FIG. 2 (c).
As shown by, the inner surface of the transparent substrate 11 is applied by screen printing,
A glass paste film is formed so as to have a thickness of about 1 μm to 1 μm, and temporarily baked at 80 ° C.

In the present embodiment, the transparent photosensitive lead glass paste comprises 80% by weight of an inorganic component and 20% by weight of an organic component. Here, in the transparent photosensitive lead glass paste, the inorganic component is made of a Bi-Zn-B-Si glass material, and the organic component is made of a cellulose resin and an organic solvent. Next, in a glass paste film patterning step S40 (see FIG. 2D), the glass paste film b is developed and exposed by photolithography and patterned to form a plurality of stripe-shaped glass paste film portions c. At this time, the portion of the glass paste film b on the exposed surface 12a of each auxiliary electrode 12 is uniformly removed from the exposed surface 12a.

Here, the patterning process of the glass paste film b is performed by taking the width G of the auxiliary electrode 12 and the gap G between the opposing side surfaces of the glass paste film portion c into consideration in consideration of the width of the auxiliary electrode 12.
Of about 10 μm in a groove shape. Then, the glass paste film portion main firing step S50 (FIG. 2E)
), Each glass paste film portion c is baked at 550 ° C. With this baking, each glass paste film portion c is once melted and flows to fill each gap G and form each flattened film 13. In addition, since the width of each gap G is set to be appropriate, each glass paste film portion c only flows into each gap G depending on its melt flow, and flows onto the exposed surface 12a of each auxiliary electrode 12. There is no. Further, since each auxiliary electrode 12 is formed of a photosensitive silver paste and has a porosity, each glass paste film portion c is melted, so that a part of the glass paste film portion c is formed inside each auxiliary electrode 12. Is absorbed.

At this time, each flattening film 13 is formed in a tapered shape on the surface 13a of the portion buried in each gap G by the surface tension accompanying the melting of the glass paste film portion. 13 is flattened so as to have a uniform surface by a leveling effect accompanying the melting of the glass paste film portion, and has a thickness larger than the thickness of each auxiliary electrode 12. Since the flattening films 13 are flattened by the melting of the glass paste film portion, the flattening by polishing is unnecessary.

By the way, when the viscosity characteristics of the transparent photosensitive lead glass paste (J1312 type) with respect to the temperature were examined, a graph L as shown in FIG. 3 was obtained.
In the graph of FIG. 3, the vertical axis is a logarithmic scale. According to this, the viscosity of the above-mentioned transparent photosensitive lead glass paste sharply decreases with a rise in the temperature range of 400 ° C. to 700 ° C. Therefore, it can be seen that at the above-mentioned main firing temperature of 550 ° C., the viscosity of the above-mentioned transparent photosensitive lead glass paste is considerably low. Therefore,
As described above, it can be seen that at the time of the main firing, each of the glass paste film portions c can easily fill each of the gaps G due to a decrease in viscosity accompanying the melting.

Further, the effect of burying each gap G as described above can be further exhibited when the width of the auxiliary electrode 12 is small. After the processing of the glass paste film part main firing step S50 is completed as described above, the transparent electrode material forming step S6
0 (see FIG. 2 (f)), ITO was
Then, an ITO film d is formed on the exposed surface 12a and the surface of each flattening film 13 by sputtering or printing and fired.

Here, since each flattening film 13 has the tapered surface 13a as described above, the ITO is smoothly spread over the tapered surface 13a of each flattening film 13 and the exposed surface 12a of each auxiliary electrode 12. Is formed. Therefore, ITO
The occurrence of disconnection of the film d can be reliably prevented. Next, in the transparent electrode forming step S70 (see FIG. 2G), the IT
A plurality of stripe-shaped transparent electrodes 14 are formed on the O film d by a combination of photolithography and dry etching. Here, the reason for not using the wet etching method is
This is because the lead glass paste dissolves in the ITO etching solution.

As described above, the melt flow of each flattening film 13 does not reach the exposed surface 12a of each auxiliary electrode 12 during the main firing in the glass paste film portion main firing step S50, as described above. , The ITO film d is formed in uniform contact with the exposed surface 12 a of each auxiliary electrode 12. Therefore, I
Each transparent electrode 14 formed from the TO film d and each auxiliary electrode 1
There is no room for interfering objects between the transparent electrodes 14 and
The conductivity between the electrode and each auxiliary electrode 12 can be satisfactorily secured.

Each transparent electrode 14 has
Each is formed so as to cover the entire exposed surface 12a of each corresponding auxiliary electrode 12 and to cover a part of each surface of the planarizing film 13 on both sides thereof. Thereafter, in an insulating film forming step S80 (see FIG. 2H), tantalum oxide, which is an insulating material, is applied to the surface 13a of each flattening film 13 via each transparent electrode 14 by sputtering to form an insulating film (FIG. 2). (See symbol e in (h)).

The insulating film e may be formed by applying an organic titanium-based material instead of tantalum oxide to the surface 13a of each flattening film 13 via each transparent electrode 14 by a sol-gel method. Next, an alignment film forming step S90 (FIG. 2)
In (i), an alignment film material (for example, polyimide) is formed on the insulating film e as an alignment film (see reference numeral f in FIG. 2H).

Thus, the manufacture of the lower electrode substrate 10 is completed. In addition, since the lower electrode substrate 10 has a structure in which the auxiliary electrode 12 is embedded between the planarizing films 13, the height of the planarizing film 13 and the auxiliary electrode 12 is adjusted so that the transparent electrode Since the lowering of the wiring resistance of No. 14 can be ensured, the aperture ratio of the display area as the liquid crystal panel does not decrease.

Accordingly, the lower electrode is adapted to secure a good connection between the transparent electrode and the auxiliary electrode uniformly while maintaining the film thickness and the aperture ratio of the auxiliary electrode 12 and the wiring resistance of the transparent electrode 14 well. The substrate 10 can be manufactured. Further, even when the lower electrode substrate 10 is superposed on the upper electrode substrate 20 via a seal and a spacer to form a liquid crystal panel, the distance between the two electrode substrates 10 and 20 is uniform. As a result, the occurrence of display unevenness of the liquid crystal panel can be favorably prevented.

In the first embodiment, an example in which a photosensitive silver paste is used as a material for forming the auxiliary electrode 12 has been described. Alternatively, copper for plating or the like may be used as a material for forming the auxiliary electrode 12. May be adopted. Also,
In the first embodiment, in the glass paste film patterning step S40, each auxiliary electrode 1 of the glass paste film b is accompanied with the patterning of the glass paste film b.
2 is uniformly removed from the exposed surface 12a. Instead, the portion of the glass paste film b on the exposed surface 12a of each auxiliary electrode 12 is replaced with the exposed surface 12a. During the main firing in the subsequent glass paste film part main firing step S50, the portion of the glass paste film b on the exposed surface 12a of each auxiliary electrode 12 is melted to form a portion in each gap G. You may make it fill in. (Second Embodiment) FIG. 4 shows a second embodiment of the present invention.

The manufacturing process of the lower electrode substrate of the liquid crystal panel in the second embodiment is the same as the manufacturing process of the lower electrode substrate described in the first embodiment except that the glass paste film patterning step S40 and the glass paste film portion Instead of the main firing step S50, a glass paste film main firing step S10
0 is adopted. Other configurations are the same as those in the first embodiment.

Next, a method of manufacturing the lower electrode substrate of the liquid crystal panel according to the second embodiment will be described with reference to FIG. After finishing the glass paste film forming step S30 in the same manner as described in the first embodiment, in the glass paste film part main firing step S100 (see FIG. 4E),
The glass paste film b is finally fired at 550 ° C. In addition,
The glass paste of the second embodiment is made of a non-photosensitive lead glass paste.

With this firing, the glass paste film b is melted, and the melted glass paste film b exerts the leveling effect. Moreover, since the photosensitive silver paste forming the auxiliary electrode 12 is porous, the photosensitive silver paste absorbs the film portion of the molten glass paste film b on the auxiliary electrode 12 like a sponge. As described above, at the time of the main firing, each auxiliary electrode has a synergistic effect of the characteristic of the glass paste that the viscosity is rapidly lowered by melting and the characteristic of the photosensitive silver paste that absorbs the glass paste of each auxiliary electrode 12. Even if the glass paste film b is formed after the formation of the substrate 12, the exposure of the exposed surface 12a of each auxiliary electrode 12 can be satisfactorily secured.

As a result, the glass paste film patterning step S40 as described in the first embodiment and the subsequent glass paste film portion main baking step S50 are substantially the same as in the first embodiment. Similarly, the flattening of each flattening film 13, the formation of the tapered surface portion 13 a of each flattening film 13, and the effects thereof can be achieved. The properties of the glass paste and the synergistic effect of the photosensitive silver paste in the glass paste film main firing step S100 are even more remarkable when the width of the auxiliary electrode 12 is relatively large. (Third Embodiment) FIGS. 5 and 6 show a third embodiment of the present invention.

In the third embodiment, after the auxiliary electrode material forming step S10 and the auxiliary electrode forming step S20 are performed in the same manner as described in the first embodiment, the glass paste forming step S30 (5 (c )), A flattening material (transparent lead glass paste or the like) is formed as a glass paste film b so as to be thicker than the silver paste by about 0.1 to 0.2 μm, unlike the first embodiment. Temporarily bake at ℃. In addition, the thickness of the lead glass is smaller than that of the silver paste after the main firing.

Next, the glass paste film portion main firing step S1
At 10 (see FIG. 5D), the glass paste film b
Main firing is performed at 50 ° C. Here, after the main baking, the planarizing material is not present on the silver paste film a formed in the auxiliary electrode material forming step S10 due to the following two effects. One is a leveling effect of the lead glass paste melted at the time of the main firing, and the other is a silver paste film a.
Is an effect that the silver paste film a absorbs the lead glass paste on it like a sponge because it is porous.

As described above, by combining the porous silver paste and the flattening material whose viscosity rapidly decreases during the main firing, the auxiliary electrode can be easily formed even if the flattening film is formed after the silver paste film a is formed. 12 (exposure of the exposed surface 12a) is possible. As described above, if the above steps are used, a structure in which the head of the auxiliary electrode 12 is protruded as shown in FIG. 6 is completed. In this case, the viscosity of the lead glass paste film serving as the flattening film 13 decreases during the main firing, and the lead glass paste film is recessed between the auxiliary electrodes 12 as shown in detail in FIG.

Accordingly, the polishing step S120 (FIG. 5)
In (e), constant-pressure polishing such as belt polishing or tape polishing is performed to eliminate the concave state between the auxiliary electrodes 12. Here, since the difference in hardness between the silver paste and the lead glass paste is ten times, the silver paste is usually sharpened quickly and conventionally cannot be polished well. However, in this embodiment, since the lead paste is contained in the silver paste, a substantial difference in hardness is reduced, and uniform polishing can be performed.

Further, the particle size of silver is about 3 to 5 μm, and if polished only with a silver paste, the silver particles are removed and unevenness after polishing becomes 3 to 5 μm. However, by fixing the silver particles with a lead glass paste, it is possible to realize irregularities of about 30 nm. Thereby, the planarizing film 1 including the auxiliary electrode 12 is formed.
3 can be satisfactorily realized. Next, in the transparent electrode material film forming step S60 (see FIG. 5F), ITO is formed as the ITO film d in the same manner as described in the first embodiment, and then the transparent electrode forming step S70 (FIG. 5). (See (g))
In the above, the ITO film d is
4 is formed by patterning.

Here, when the distance between the transparent electrodes 14 is large (100 μm or more), the electrodes can be directly formed by printing, but when the distance is smaller than that, a photolithography method is used. In this case, the wet etching method is not suitable because the ITO and the lead glass paste are dissolved by the same etching solution. Therefore, a dry etching method or a lift-off method is used.

When ZnO is used instead of ITO, etching can be performed with a weak acid such as acetic acid, and wet etching can be performed. At this time, the level difference between the flattening film 13 and the auxiliary electrode 12 formed in the structure of FIG. 6 is 0.5 μm or less, thereby preventing the level change of the transparent electrode 12. Further, an insulating film forming step S80 (see FIG. 5H)
In the above, tantalum oxide for preventing short circuit between the upper and lower electrode substrates is formed by sputtering or an organic titanium-based material is formed as an insulating film e by a sol-gel method.

Further, an alignment film forming step S90 (FIG. 5)
In (i)), the alignment film f is formed by printing in the same manner as in the first embodiment. In the case of this method, the material for forming the auxiliary electrode 12 is not limited to the silver paste, but may be a porous material such as a copper paste or an aluminum paste. In addition, by dissolving the lead glass paste into the porous silver paste as described above, usually, when a metal that is a different material is embedded in a flattening material such as lead glass (there is also an acrylic resin or the like). In addition, the difference in the thermal expansion coefficient may cause a problem such as occurrence of peeling crack due to cold heat. However, by dissolving a flattening material such as lead glass into a porous silver paste as in the present method, the substantial difference in expansion coefficient is reduced, and the above-described problem does not occur.

In the second embodiment, the auxiliary electrode 1
Although an example in which a photosensitive silver paste is used as the material for forming the second electrode 2 has been described, a porous material such as a copper paste or an aluminum paste may be used as a material for forming the auxiliary electrode 12 instead. Further, in the embodiment of the present invention, an example (first embodiment) in which a transparent photosensitive lead glass paste is employed as a material for forming the flattening film 13 has been described. However, the present invention is not limited to this. May be adopted as a material for forming the flattening film 13.

In practicing the present invention, the present invention is not limited to the transmission type liquid crystal panel electrode substrate described in each of the above embodiments, but may be applied to a reflection type liquid crystal panel electrode substrate. In the embodiment of the present invention, in the first or second embodiment, when flatness is required before forming the ITO film, the constant-pressure polishing as described in the third embodiment is performed. May be implemented.

Further, when the belt is polished and the tape is polished by Oscar polishing, which is usually used for polishing glass, the surface roughness is equal to that of glass. Further, in carrying out the present invention, the present invention is not limited to the matrix driving type liquid crystal panel electrode substrate described in each of the above embodiments, and may be applied to various driving type liquid crystal panel electrode substrates. Good.

In practicing the present invention, the liquid crystal of the liquid crystal panel is not limited to a smectic liquid crystal, but may be various liquid crystals. In practicing the present invention,
The present invention is not limited to a liquid crystal panel, and may be applied to various types of display panel electrode substrates such as an electroluminescence panel.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of a liquid crystal panel according to the present invention.

FIGS. 2A to 2I are process diagrams showing a method for manufacturing a lower electrode substrate of the liquid crystal panel.

FIG. 3 is a graph showing the relationship between viscosity and temperature in each lot of a transparent photosensitive lead glass paste.

FIG. 4 is a manufacturing process diagram of a lower electrode substrate according to a second embodiment of the present invention.

FIG. 5 is a manufacturing process diagram of a lower electrode substrate according to a third embodiment of the present invention.

FIG. 6 is an enlarged sectional view of a main part of the lower electrode substrate shown in FIG. 5 (d).

FIGS. 7 (a) to 7 (f) are manufacturing process diagrams of a conventional electrode substrate.

[Explanation of symbols]

11: transparent substrate, 12: auxiliary electrode, 12a: exposed surface, 1
3: flattening film, 13a: tapered surface portion of flattening film,
14: transparent electrode, G: gap.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiromichi Kato 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Kazushige Suematsu 1-1-1, Showa-cho, Kariya-shi, Aichi Co., Ltd. F term in DENSO (reference) 2H092 GA17 HA02 HA04 MA05 MA10 MA13 MA19 MA37 NA01 NA07 NA16 NA19 NA28 QA10 QA13 QA14 5C094 AA07 AA55 BA43 CA19 DA13 EA04 EA10 FB16 HA08

Claims (8)

[Claims] An auxiliary electrode forming step of forming a plurality of stripe-shaped auxiliary electrodes on the inner surface of a substrate by using a metal material (S10, S20); Forming a material film by coating the inner surface of the substrate so as to embed the electrodes (S30); and forming the material film so as to form groove-shaped gaps on both sides in the width direction of each of the auxiliary electrodes. A patterning process step (S40) for performing a patterning process, and filling the gaps such that the material film patterned in the patterning process process is melted by firing to expose the tip end surfaces of the auxiliary electrodes. A material film baking step (S50) of forming each flattening film (13) by absorbing a part of the low melting point flattening film forming material into each of the auxiliary electrodes; Method for producing a longitudinal direction along a main electrode forming step of respectively forming a stripe-shaped main electrode (14) (S60, S70) and the electrode substrate for a display panel comprising a. 2. The method according to claim 1, wherein a photosensitive silver paste is used as the metal material in the auxiliary electrode forming step, and a photosensitive lead glass paste is used as the low melting point flattening film forming material in the material film forming step. Item 2. A method for manufacturing a display panel electrode substrate according to Item 1. 3. An auxiliary electrode forming step (S10, S20) of forming a plurality of stripe-shaped auxiliary electrodes (12) from a porous metal material on an inner surface of a substrate (11); A material film forming step (S30) of applying a material film by coating the inner surface of the substrate so as to embed each auxiliary electrode, and melting the material film by firing; A material film baking step (S10) for forming each planarizing film (13) so that the film portion corresponding to the front end surface is absorbed by each of the auxiliary electrodes and the front end surface is exposed.
0) and a main electrode forming step (S60, S70) of forming a stripe-shaped main electrode (14) along the longitudinal direction on the tip end surface of each of the auxiliary electrodes. 4. The method according to claim 1, wherein a photosensitive silver paste is used as the porous metal material in the auxiliary electrode forming step, and a lead glass paste is used as the low melting point flattening film forming material in the material film forming step. Item 4. The method for producing an electrode substrate for a display panel according to Item 3. 5. The method according to claim 1, wherein, in the material film firing step, the flattened film is formed in a tapered shape on both side portions (13a) in the width direction of the auxiliary electrodes on the surface. 5. The method for manufacturing a display panel electrode substrate according to any one of items 4. 6. The flattening film present between the auxiliary electrodes by a part of the low melting point flattening film forming material being absorbed by the auxiliary electrodes in the material film baking step. Between the material film baking step and the main electrode forming step, in a state protruded by the flattened films in the concave state so as to eliminate the concave state. The method of manufacturing an electrode substrate for a display panel according to claim 3, further comprising a polishing step of polishing each of the auxiliary electrodes and each of the planarization films including a top portion of each of the auxiliary electrodes. 7. A substrate (11), auxiliary electrodes (12) and planarizing films (13) alternately formed in a plurality of stripes on the inner surface of the substrate, and a tip surface (12a) of each of the auxiliary electrodes. A display panel electrode substrate including a main electrode (14) formed in a stripe shape along the longitudinal direction thereof, wherein a material constituting the planarizing film is mixed in each of the auxiliary electrodes. Electrode substrate for display panel. 8. The electrode substrate for a display panel according to claim 7, wherein both sides (13a) of each auxiliary electrode in the width direction of the surface of each of the planarization films are formed in a tapered shape. .