JP2001308496A - Method for forming electrode on functional film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an electrode having high reliability without bringing about a deformation of a functional film. SOLUTION: A method for forming the electrode on the functional film 1 comprises a step of patterning a conductive paste 10 on a surface (one main surface) of the film 1 in which a resin film is used as a substrate, and a step of forming the electrode by curing the paste 10 by radiating a light (e.g. a halogen light) from a rear surface side (the other main surface side) of the film 1 to the paste 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an electrode on a functional film in which a conductive film is formed on a functional film on which a functional film such as an antireflection film or an antistatic film is formed.

[0002]

2. Description of the Related Art A functional film including a conductive film is attached to a surface of a display panel of a cathode ray tube (CRT), a plasma display panel (PDP), or the like for the purpose of preventing static electricity and preventing unnecessary electromagnetic wave radiation.

[0003] This functional film uses a resin film made of polyethylene terephthalate (PET) or the like as a substrate, forms a plurality of functional films including a conductive film made of ITO (Indium Tin Oxide) on its surface, and forms a display panel on its back surface. Is formed with an adhesive layer for bonding.

[0004] An electrode for electrically connecting to the conductive film and grounding is formed on the surface of the functional film.
This electrode is formed by patterning a conductive paste in several places on the functional film and heating and curing the paste.

Conventionally, as methods for forming electrodes on this functional film, (1) hot plate method, (2) far infrared heater heating method, (3) indirect resistance heating method, (4) hot air method, (5)
There are others (arc heating method, electron beam heating method, etc.).

(1) The hot plate method is a method in which a functional film is brought into close contact with a hot plate, and a conductive paste applied to the surface is heated and cured by the heat of the hot plate.

(2) The far-infrared heater method is a method of irradiating far-infrared rays using a ceramic heater or the like to heat and cure the conductive paste.

(3) In the indirect resistance heating method, a heating furnace using a nichrome wire or the like is formed, and a functional film coated with a conductive paste is put into the heating furnace, and a conductive film is formed by convection heat transfer in an atmosphere inside the heating furnace. This is a method of heating and curing the conductive paste.

(4) The hot air method is a method in which heated air is blown toward a conductive paste and the conductive paste is heated and cured by the heat.

(5) As another method, in an arc heating method or an electron beam heating method, a functional film coated with a conductive paste is put into a furnace for generating an arc or an electron beam, and the conductive paste is heated and hardened. Is the way.

In any of the methods, the electrode formed by heating and curing the conductive paste is maintained at a predetermined adhesion strength with the functional film (mechanical properties), and has an electrical resistance that can be used as an electrode. (Electrical characteristics) is required.

[0012]

However, such a method for forming an electrode on a functional film has the following problems. That is, in the above (1) hot plate method,
Since the functional film is placed on a hot plate for heating, the conductive paste on the surface is heated by heat conduction through the hot plate, which requires a long heating time, during which the functional film undergoes thermal deformation. is there.

In the above (2) far-infrared heater method, the center spectral peak of far-infrared rays is 4 μm to 8 μm, and the heating efficiency for the conductive paste applied with a thickness of several tens μm is low. For this reason, the heating efficiency for a functional film having a thickness of about 180 μm is higher, and there is a problem that the functional film is heated more than necessary and deformed.

[0014] In the above (3) indirect resistance heating method, since the infrared component effective for heat absorption is small and convection heat transfer for heating the atmosphere of the entire heating furnace is mainly used, the heating in a short time is performed. Not suitable for (rapid heating).

In the hot air method (4), the conductive paste moves due to the wind pressure applied to the conductive paste, and the thickness of the formed electrode becomes uneven, which causes variations in the adhesive strength and electric resistance. There's a problem.

In addition, the arc heating method and the electron beam heating method as (5) other methods require large-scale equipment for generating an arc or an electron beam, and are not practical.

[0017]

SUMMARY OF THE INVENTION The present invention is a method for forming an electrode on a functional film, which has been made to solve such a problem. That is, the present invention provides a step of patterning a conductive paste on one main surface of a functional film using a resin film as a substrate, and irradiating the conductive paste with light from the other main surface side of the functional film to cure the electrode. Forming a step.

In the present invention, light is irradiated from the other principal surface of the functional film having the conductive paste applied to one principal surface, and the light is efficiently absorbed by the conductive paste through the functional film. Let me. Thereby, heating starts from the side of the conductive paste that is in contact with the functional film,
The adhesion of the cured electrode can be ensured.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. That is, the method for forming an electrode of a functional film according to the present embodiment is a method of forming an electrode for conduction on a functional film mainly attached to the surface of a display panel such as a CRT or a PDP. , Organic silver) is thermally decomposed into electrodes.

FIG. 1 is a process diagram for explaining the attachment of a functional film including the electrode forming method of the present embodiment. First, a paste liquid is prepared in which a small amount of a resin (for example, epoxy resin) and a solvent are mixed with an organometallic compound in advance. In this paste liquid, the organometallic compound is in a state where the metal compound is dispersed in a colloidal state.

The functional film is prepared in a pre-processed state, and the surface (one main surface) of the functional film is prepared.
Next, the previously prepared paste liquid is applied in a predetermined shape by screen printing or the like (step S1). In the case of a CRT, it is applied at several places along the four corners and the lower side of the functional film. The applied thickness of the paste is about 25 μm.

Next, the paste liquid printed and coated on the surface of the functional film is dried (step S2) and baked (heat treated).
Thus, the organic metal compound in the paste is thermally decomposed (step S3). This pyrolysis hardens the paste,
An electrode having a predetermined electric resistance value is formed. The present embodiment is characterized in that in the heat treatment step of the paste, the functional film is not thermally deformed, and the paste can be appropriately thermally decomposed.

Thereafter, the functional film is attached to the front surface of the CRT via the adhesive layer on the back surface of the functional film on which the electrodes are formed (step S4).

Next, the heat treatment of the paste, which is a feature of the present embodiment, will be described. FIG. 2 is a schematic diagram illustrating a state of heat treatment of the paste. In the present embodiment, the paste has a higher light absorption rate than the functional film, and the light cures the paste to form an electrode.

For example, the functional film 1 has a thickness of 0.18 m
m of polyethylene terephthalate (PET), the central wavelength is in the near infrared region (for example, the central wavelength is 0.9 μm).
m to 1.0 μm). In the present embodiment, the paste 10 is irradiated with halogen light using the halogen light source 2.

In the present embodiment, the halogen light from the halogen light source 2 is irradiated from the back surface (the other main surface side) of the functional film 1 on which the paste 10 is not applied. As a result, the halogen light emitted from the halogen light source 2 impinges on the side of the paste 10 that is in contact with the functional film 1 via the functional film 1. For this reason, the paste 10 is heated from the side that is in contact with the functional film 1, so that the adhesion of the cured electrode can be ensured.

FIG. 3 is a diagram showing spectral characteristics of halogen light. In this figure, the horizontal axis represents the wavelength, the vertical axis represents the radiation intensity, and the central wavelength of the halogen light is 0.9 μm to 1.0 μm.
m. On the other hand, the center wavelength of far infrared rays is 4 μm to 8 μm.
μm. In other words, in the far-infrared, heat absorption to the functional film is high, and if the time necessary for sufficiently decomposing the paste is taken, thermal deformation of the functional film may occur. On the other hand, since the center wavelength of the halogen light used in the present embodiment is 0.9 μm to 1.0 μm, heat absorption by the functional film is low, and the paste can be efficiently heated through the functional film.

Next, the irradiation time of the halogen light will be described. In this embodiment, about 25 μm
An m-thick paste is printed and applied, and halogen light is irradiated from the back side of the functional film. At this time, irradiation is performed with the distance between the halogen light source and the back surface of the functional film set to, for example, 70 mm.

FIG. 4 is a diagram showing the relationship between the irradiation time and the film surface temperature. When the halogen light is irradiated from the back surface of the functional film under the above conditions, in this embodiment, the temperature of the film surface reaches 120 ° C. to 140 ° C. in 25 seconds, and the baking of the paste is completed. At this time, the electrode thickness (the thickness after drying the paste) is 0.5 μm.

FIG. 5 is a diagram showing the relationship between the irradiation time of halogen light and the sheet resistance of the electrode. That is, the sheet resistance decreases with the irradiation time of the halogen light, and enters a stable region when the irradiation time exceeds 20 seconds. If the sheet resistance is 50Ω or less, a sufficient function as an electrode is exhibited.

As described above, in this embodiment, the baking of the paste is completed by irradiating the halogen light for 25 seconds, and the sheet resistance enters a stable region of 50Ω or less by the irradiation for 25 seconds. By irradiating with halogen light for 25 seconds, the film surface reaches 120 ° C. to 140 ° C., but at such a temperature, no thermal deformation occurs in the functional film. That is, in the present embodiment, it is possible to form an electrode having a sheet resistance in a stable region without thermally deforming the functional film.

FIG. 6 is a view for explaining the adhesion of the electrodes. In FIG. 6, the horizontal axis is the electrode thickness, and the vertical axis is the value (remaining amount) obtained by the Gobang test (JIS, K5600-5-6: 1999 General Test Method for Paints, Part 5: Mechanical Properties of Coating Film). The electrode is obtained by firing a paste at 120 to 140 ° C.

Thus, it can be seen that as the electrode thickness increases, the value of the gobang test decreases, and the adhesion decreases. In this embodiment, the electrode thickness after firing the paste is 0.4.
Since it is from μm to 0.6 μm, it has sufficient adhesion.

That is, in the present embodiment, the halogen film is irradiated from the back surface (the side where the paste is not applied) of the functional film. Is heated. Thereby, uniform heating of the paste can be achieved.

Further, since the paste-coated surface is close to a black body, heat is directly absorbed by irradiating halogen light from the back surface of the functional film. Thereby, the paste is thermally decomposed uniformly without partial heating. Therefore, it is possible to eliminate uneven heating in the paste and obtain strong adhesion to the functional film by uniform thermal decomposition.

Next, an example of application of a functional film having electrodes formed by the method of the present embodiment to a CRT will be described with reference to FIGS. That is, the CRT 20 is connected to the display panel 2.
1, a funnel 22 joined to the display panel 21 with frit glass, and a neck tube 23 constitute a vacuum vessel.

A panel reinforcing band 24 for explosion proof is attached to the outer peripheral portion of the display panel 21.
The panel reinforcing band 24 is made of a conductive material such as metal and is grounded through a ground wire (not shown).

On the inner surface of the display panel 21, a phosphor screen 25 coated with phosphors of red, green, and blue light emission is formed.
A color selection mask (not shown) is arranged close to the phosphor screen 25. An electron beam emitted from an electron gun (not shown) accommodated in the neck tube 23 passes through the color selection mask, reaches the phosphor screen 25, and excites a predetermined phosphor to emit light. I have.

The functional film 1 formed on the surface of the display panel 21 of the CRT 20 includes a hard coat layer 13, a first insulating layer 14, a conductive layer 15, and a second insulating film on one surface of a transparent plastic film substrate 12. This is a laminate in which a layer 16 and an antifouling coat layer 17 are laminated in this order, and an adhesive layer 11 is formed on the other surface of the plastic film substrate 12. These layers are formed by techniques such as sputtering, vapor deposition, and wet coating.

On the surface of the antifouling coat layer 17, which is the surface on the side of the second insulating layer 16, an electrode 10a that is electrically connected to the conductive layer 15 is provided. The electrode 10a is formed by thermally decomposing the paste with the light from the halogen light source described above.

Further, the adhesive layer 11 formed on the other surface of the plastic film substrate 12 is used to attach the functional film 1 to a CRT.
This is a layer to be adhered to the surface of the display panel 21 of 20 and its surface is covered with a release paper (not shown) before the attachment.

The plastic film substrate 12 is made of, for example, polyethylene terephthalate (PE).
T), polycarbonate (PC), polymethyl methacrylate (PMMA), styrene methyl methacrylate (MS), polystyrene (PS) and the like. The thickness of the plastic film substrate 12 is set to, for example, about 0.18 mm.

The hard coat layer 13 is for reinforcing the surface hardness and abrasion resistance of the functional film 1, and is formed as a thin film layer of, for example, an acrylic ultraviolet curing resin.

The laminate composed of the first insulating layer 14, the conductive layer 15, and the second insulating layer 16 laminated on the hard coat layer 13 functions as an anti-reflection (AR) film. This laminate is formed as a multilayer optical thin film so that when the functional film 1 is attached to the surface of the display panel 21 of the CRT 20, reflection of external light is reduced, and preferable images such as video and character information are reproduced. ing.

The first insulating layer 14 and the second insulating layer 16
Is formed of, for example, silicon oxide. The conductive layer 15 is formed as a transparent conductive layer made of, for example, an ITO thin film.

The antifouling coat layer 17 which is laminated on the second insulating layer 16 and which is the outermost surface of the functional film 1 does not easily adhere to the surface, for example, fingerprints or the like when a human hand directly touches the surface. Further, the attached dirt can be easily removed by dry wiping or water wiping.

As the material of the antifouling coat layer 17, for example, a coating agent containing a perfluoro group in a silicone resin base or an acrylic resin base is used. In the present embodiment, the AR film and the antifouling coat layer 17 formed of a laminate of the first insulating layer 14, the conductive layer 15, and the second insulating layer 16 are formed to a thickness of, for example, about 0.1 μm.

On the other hand, the electrode 10a formed on the surface of the antifouling coat layer 17 is formed by thermally decomposing a film containing an organic metal (eg, gold, silver, copper, etc.) compound, a resin such as an epoxy resin, and a solvent. It is made of a conductive film formed in an island pattern.

The electrode 10a has a constituent component of the second
It is impregnated so as to reach the conductive layer 15 through gaps, cracks, and peeled portions of the insulating layer 16 and is electrically connected to the conductive layer 15. It is provided in a state of being adhered to. Here, the electrode 10a is formed to a thickness of, for example, about 0.5 μm.

The CRT 2 in which the conductive structure of the functional film 1 configured as described above is used on the surface of the display panel 21
0, the conductive layer 15 and the second insulating layer 16 are disposed on the surface of the display panel 21 such that the conductive layer 15 side is the display panel 21 side, and is attached to the lowermost adhesive layer 11. Can be

Then, the panel reinforcing band 24 attached to the outer peripheral portion of the display panel 21 and grounded, and the electrode 10a formed on the surface of the functional film 1 are joined via the conductive tape 30 to thereby ground. It has been done.

The conductive tape 30 is made of, for example, a copper foil tape, and has a base film 31 and a base film 3.
1 is formed of a copper foil (conductive film) 32 (hereinafter, the conductive tape 30 is referred to as a copper foil tape 30). Further, a conductive adhesive (not shown) is applied to the surface of the copper foil 32.

Therefore, the panel reinforcing band 24 and the electrode 10a formed on the surface of the functional film 1 are joined by the conductive adhesive of the copper foil tape 30, and the functional film 1
Is grounded through the conductive adhesive, the copper foil 32, and the panel reinforcing band 24.

In the conductive structure of the functional film 1 described above, the electrode 10 a is formed of a conductive film obtained by thermally decomposing an organometallic compound, and the components of the electrode 10 a reach the conductive layer 15 through the second insulating layer 16. Therefore, conduction between the conductive layer 15 of the functional film 1 and the electrode 10a can be reliably achieved.

At the same time, the contact resistance can be reduced as compared with an electrode using solder. Therefore,
Since the high pressure discharge resistance generated in the CRT 20 or the like is good,
When applied to the surface of the display panel 21 of a device such as the CRT 20 in which a high-voltage discharge occurs, it is possible to prevent a decrease in the reliability of a conductive portion due to the high-voltage discharge.

The electrode 10a is formed in a state in which the constituent resin or the like is impregnated in the functional film 1, so that the function film 1 and the electrode 10a are compared with the electrode using solder. The adhesive strength becomes strong.

Further, the electrode 10a can be easily formed to have a uniform thickness by using a conductive film obtained by thermally decomposing an organometallic compound. Therefore, CRT2
0, the functional film 1 is provided on the surface of the display panel 21,
When the electrode 10a on the surface of the functional film 1 and the copper foil tape 30 are connected, it is possible to prevent the adhesive strength from being varied.

Further, since the adhesive strength between the electrode 10a and the copper foil tape 30 can be sufficiently and stably secured, the conductive layer 15 of the functional film 1 and the electrode 10a and the copper foil tape 30 can be reliably provided. C that can achieve stable conduction and prevent charging or the like of the surface of the display panel 21
The RT 20 can be realized.

In the above-described embodiment, the electrode formation of a functional film used mainly for a display panel such as a CRT or a PDP has been described as an example. However, the present invention is not limited to this. The present invention is applicable even when forming an electrode.

[0060]

As described above, according to the method for forming an electrode on a functional film of the present invention, the following effects can be obtained.
That is, since the conductive paste applied to the functional film can be accurately thermally decomposed and cured in a short time to form an electrode, a highly reliable electrode can be formed without causing deformation of the functional film. This makes it possible to attach the functional film to a display panel or the like without involving air.

Further, the electrodes can be formed in a short time, and the productivity can be improved. Further, the thickness of the electrode can be made uniform by uniform thermal decomposition, and the adhesive strength and the sheet resistance of the electrode can be made uniform. This makes it possible to improve the reliability of connection and conduction between the electrode and another member. Moreover, by using a halogen light source, it is possible to form electrodes on a functional film with a simple apparatus configuration without requiring a large facility such as a heating furnace.

[Brief description of the drawings]

FIG. 1 is a process diagram for explaining the attachment of a functional film including the electrode forming method of the present embodiment.

FIG. 2 is a schematic diagram illustrating a state of heat treatment of a paste.

FIG. 3 is a diagram showing spectral characteristics of halogen light.

FIG. 4 is a diagram showing the relationship between irradiation time and film surface temperature.

FIG. 5 is a diagram showing the relationship between the irradiation time of halogen light and the sheet resistance of an electrode.

FIG. 6 is a diagram illustrating the adhesion of electrodes.

FIG. 7 is a schematic diagram illustrating an example of application to a CRT.

FIG. 8 is an enlarged sectional view of an electrode portion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Function film, 2 ... Halogen light source, 10 ... Paste, 10a ... Electrode, 20 ... CRT

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshiharu Matsushita F-term (reference) 2K009 AA02 AA15 BB24 DD02 DD04 DD06 EE03 5C058 AA11 AB12 DA01 DA10 5E343 AA02 AA16 AA33 BB25 BB60 DD02 ER42 ER44 FF11 GG02 GG11

Claims (7)

[Claims] 1. A step of patterning a conductive paste on one main surface of a functional film using a resin film as a substrate, and irradiating the conductive paste with light from another main surface side of the functional film to cure the conductive paste. Forming an electrode on the functional film. 2. The method for forming an electrode on a functional film according to claim 1, wherein the conductive paste has a higher absorptivity of the light than the functional film. 3. The method for forming an electrode on a functional film according to claim 1, wherein the light has a center wavelength in a near infrared region. 4. The light having a center wavelength of 0.9 μm to 1.
The method for forming an electrode on a functional film according to claim 1, wherein the thickness is 0 μm. 5. The method for forming an electrode on a functional film according to claim 1, wherein the light is light emitted from a halogen light source. 6. The method according to claim 1, wherein the resin film is made of polyethylene terephthalate. 7. The method for forming an electrode on a functional film according to claim 1, wherein the conductive paste comprises an organometallic compound.