JP2003275817A - Method for forming metallic sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forming method of a metallic sheet by which the reliability of the joining with a substrate for displays is improved by improving the flatness in a bonding surface of the metallic sheet. <P>SOLUTION: This method includes a stage where the metallic sheet 10 having a concave shape 11 in the middle principal part except the specified part 10z of the periphery is prepared and a stage where heat treatment is performed in the state where a plurality of the metallic sheets 10 are piled up by making the specified parts 10z of the periphery correspond to each other and the specified parts 10z of the periphery are pressed. <P>COPYRIGHT: (C)2003,JPO

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 a metal plate, more specifically, an organic EL (Electroluminescenc)
e) A method for molding a metal plate (sealing plate) used in an organic EL display device having a layer.

[0002]

2. Description of the Related Art In recent years, attention has been paid to organic EL devices as self-luminous devices. This organic EL element has good display characteristics because it self-luminesces, has excellent impact resistance because it is a completely solid-state element, and has low power consumption. Therefore, it is used as a light-emitting element in various display devices. Is expected to be used.

FIG. 13 is a sectional view showing an example of an organic EL display device. In the organic EL display device, as shown in FIG. 13, a predetermined organic EL element array 102 is formed on a transparent glass substrate 100. The organic EL element has a structure in which an organic EL layer is sandwiched between a cathode and an anode. Organic EL
In the display device, the holes injected from the anode and the electrons injected from the cathode are recombined inside the organic EL layer to emit light, and the light passes through the transparent anode and is emitted to the outside. A display image can be obtained.

In such an organic EL device, a dot-shaped or circular non-light-emitting display defect called a dark spot (dark defect point) occurs due to the separation of the electrode and the organic EL layer due to the invasion of water. Cheap.

For this reason, a passivation film is formed on the organic EL element array 102, and the organic EL element array 102 is capped by a back cap 108 having a recess 108a in the central main portion. The periphery of the back cap 108 except the recess 108a is adhered to the periphery of the glass substrate 100 with an adhesive layer 101.

In this way, the organic EL element array 10
2 is disposed in the recess 108a of the back cap 108, and the space 104 of the recess 108a is filled with an inert gas containing no water. Back cap 1
The moisture absorbent material 1 that adsorbs moisture on the bottom of the recess 108a of No. 08.
06 is provided.

With such a structure, moisture can be prevented from entering the organic EL element array 102 from the outside and the organic EL element array 102 can be protected from mechanical shock.

A glass substrate is often used as the back cap 108. The glass substrate has good surface flatness and can match the coefficient of thermal expansion with the glass substrate 100 on the organic EL element side, which is convenient from the viewpoint of improving the reliability of bonding.

Conventionally, the back cap 108 has been manufactured by forming a recessed portion by sandblasting or wet etching in a predetermined portion in the center of the glass substrate.

[0010]

[Background of the Invention] Back cap 108
The depth of the concave portion 108a is not only the thickness of the adsorbent 106, but also the space 104 between the adsorbent 106 and the organic EL element array 102 needs to be secured, so that the recess 108a is formed relatively deep (for example, about 0.5 mm). There is a need.

Therefore, when a recess is formed in a glass substrate by sandblasting or wet etching, the amount of processing is large, resulting in poor efficiency and an increase in cost. Further, since the glass substrate needs to have a predetermined strength even after the recess is formed, it is necessary to use a relatively thick glass substrate, and as a result, the thickness of the organic EL display device becomes thick.

As a countermeasure against this, an attempt has been made to use a metal plate as the back cap 108 instead of the glass substrate. This is a method in which a metal plate is formed by press forming or the like to form a recess in a predetermined center portion of the metal plate.

However, this method solves the problems of increased cost and increased thickness, but the flatness of the surface of the metal plate is inferior to that of the glass substrate, and the flatness of the surface is reduced due to the stress during press molding. Further deterioration causes a problem that the reliability of bonding with the glass substrate on the organic EL element side is lowered. As a result, the display defect as described above may occur due to the intrusion of moisture into the organic EL element from the outside.

The present invention has been made in view of the above problems, and it is possible to improve the flatness of the bonding surface of the metal plate and improve the reliability of the bonding with the substrate of the display device. An object is to provide a method for forming a plate.

[0015]

In order to solve the above-mentioned problems, the present invention relates to a method for forming a metal plate, which comprises a step of preparing a metal plate having a concave main part other than a predetermined peripheral portion, and a plurality of steps. And stacking the metal plates in such a manner that the predetermined peripheral portions are associated with each other, and performing heat treatment while pressing the predetermined peripheral portions.

In the present invention, first, a metal plate having a concave main portion other than the predetermined peripheral portion is prepared. In this step, the central main part of the metal plate may be pressed to form a concave shape, or the central main part of the metal plate may be etched to reduce the thickness to form the concave shape. You may form. Alternatively, the central main part of the metal plate may be etched to reduce its thickness and then pressed by press molding to form a concave shape.

After that, predetermined peripheral portions of the plurality of metal plates are stacked, for example, in contact with each other, and the peripheral portions are sandwiched by a holding jig, and the metal plates are heat-treated with a predetermined pressure applied to the peripheral portions. At this time, when forming a concave shape on the metal plate by press molding, a spacer is sandwiched between the predetermined peripheral portions of the plurality of metal plates so as to prevent the portions other than the predetermined peripheral portion of the metal plate from being contacted and deformed. May be.

By performing the heat treatment while pressing the peripheral portion of the metal plate in this manner, not only the step due to the stress (internal stress) of the metal plate itself but also the step due to the stress in the press molding is corrected. As a result, the surface of the peripheral portion of the metal plate having a predetermined portion can have a flatness equal to or higher than that of the glass substrate.

The surface of the peripheral portion of the metal plate is adhered to the peripheral portion of the substrate of the display device so that the concave portion of the central main portion of the metal plate separates the element formation region from the predetermined space. It becomes a back cap (sealing plate) to cover.

As described above, since the bonding surface of the predetermined portion of the peripheral edge of the metal plate has a flatness equal to or higher than that of the glass substrate, the reliability of the bonding between the substrate of the display device and the metal plate can be improved. it can. Therefore, when the metal plate formed by the method of the present invention is used as a back cap of an organic EL display element, it is possible to prevent moisture from entering the organic EL element from the outside, which causes a display defect. To be prevented.

Further, since the metal plate can be used as the back cap, unlike the case where the glass substrate is used, the press molding can suppress the cost increase and reduce the thickness of the back cap. Even if it is thin, sufficient mechanical strength can be obtained, so that a thin organic EL display device can be easily manufactured.

In the above-mentioned method for forming a metal plate, the metal plate may be an alloy of nickel (Ni) and iron (Fe), an alloy of nickel (Ni), iron (Fe) and cobalt (Co), or tungsten ( W) and molybdenum (Mo) are preferred.

Ni-Fe alloy, Ni-Fe-Co alloy,
Since W or Mo has a thermal expansion coefficient similar to that of the glass substrate of the display device, a metal plate made of these materials is used as an organic EL device.
When it is used as a back cap of a display element, it is possible to solve problems such as the occurrence of cracks in the adhesive layer due to the difference in coefficient of thermal expansion due to stress such as heat. Therefore, the reliability of the bonding between the substrate of the display device and the back cap can be further improved.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
Sectional drawing which shows the shaping | molding method of the metal plate of embodiment, FIG. 2 is a perspective view and sectional drawing which show an example of the holding jig used for the shaping | molding method of the metal plate of this embodiment, and FIG. 3B is a sectional view showing an example of a heat treatment apparatus used in the method for forming a metal plate of FIG. 3, FIG. 3B shows an example of a temperature profile in the furnace of the heat treatment apparatus of FIG. 3A, and FIG. FIG. 5 is a sectional view showing a metal plate (back cap) manufactured by the metal plate molding method of FIG. 5, and FIG. 5 is a sectional view showing an example of an organic EL display device to which the metal plate of the present embodiment is applied as a back cap.

In the method for forming a metal plate according to the first embodiment of the present invention, as shown in FIG. 1 (a), first, the thickness of Ni-Fe alloy (42 alloy) or the like is, for example, 0.25 to 0.3 m.
A metal plate 10a of about m and a mold 26 are prepared. In addition,
As the metal plate 10a, in addition to the Ni-Fe alloy, Ni-Fe
-Co alloy, (Kovar), tungsten (W), molybdenum (Mo), aluminum (Al), stainless steel (SUS304), etc. can be used.

The die 26 is composed of the punch 20 and the pressing member 22.
And a die 24. Then, the metal plate 10a is inserted between the pressing member 22 and the die 24, and a predetermined portion of the metal plate 10a is pressed by the punch 20 and rolled to form a recess.

Thereafter, the metal plate 10 is placed on the mold 26.
A is inserted and the punch 20 presses the metal plate 10a to roll it. As a result, as shown in FIGS. 1B and 2B, it is composed of the adhesive portion 10z at the peripheral edge predetermined portion, the rolling portion 10y connected to the adhesive portion 10z and rolled, and the pressing portion 10x connected to the rolling portion 10y. The metal plate 10 having A recess 11 is formed in the central main portion of the metal plate 10 by the pressing portion 10x and the rolling portion 10y. Since the rolling portion 10y is a portion formed by rolling the metal plate in the vicinity when the pressing portion 10x of the metal plate 10 is pressed, the rolling portion 10y is thinner than the bonding portion 10z and the pressing portion 10x. There is.

The metal plate 10 serves as a back cap (sealing plate) of a display device such as an organic EL display device, and its adhesive portion 10z is provided on the peripheral portion of the glass substrate of the display device via an adhesive layer. After being bonded, the organic EL element array is placed in the space of the recess 10x and capped by the metal plate 10.

As described above, since the metal plate 10 is adhered to the glass substrate via the adhesive layer, from the viewpoint of improving the reliability of joining due to stress such as heat, the coefficient of thermal expansion among the above-mentioned metal materials is Glass substrate (eg 4.8p
Ni-Fe alloy (for example, 4.5p)
Pm) is preferably used. From the same viewpoint, in addition to the Ni-Fe alloy, a Ni-Fe-Co alloy,
W or Mo is also preferable.

As described above, the flatness of the surface of the metal plate itself is worse than that of the glass substrate (glass substrate: 10 to 30 μm, metal plate: 50 μm or more, for example), and the flatness due to the stress due to press molding thereafter. It further deteriorates. Therefore, after the metal plate 10 is bonded to the display substrate, the reliability of the bonding is deteriorated by heat or mechanical shock,
Water may enter from the bonded portion and display defects may occur in the organic EL display device.

In the method for forming a metal plate according to the first embodiment of the present invention, the adhesive surface 1 of the metal plate 10 formed in this manner is used.
It was devised to make 0 s equal to or more than the flatness of the glass substrate.

Next, a method for flattening the bonding surface 10s of the metal plate 10 will be described.

First, as shown in FIG. 1C, a lower plate 12 made of super steel or ceramic is prepared, and then the lower plate 12 shown in FIG.
A plurality of metal plates 1 are formed on the lower plate 12 so that the bonding surface 10s of the metal plate 10 formed in the shape shown in FIG.
Place 0 on top of each other.

At this time, the adhesive surface 1 of the bottom metal plate 10
0s contacts the lower plate 12, and the plurality of metal plates 10 are stacked with their adhesive portions 10z contacting each other.
Further, since the rolled portion 10y of the metal plate 10 is thinner than other portions by being rolled, the metal plate 10y
When a plurality of the rolled parts 10y are stacked, the rolled parts 10y are stacked in a state in which a gap 13 is generated without making contact with each other.

In the first embodiment, the plurality of metal plates 1
When stacking 0s, the pressing portions 10x come into contact with each other. Therefore, when the number of the metal plates 10 is large, it is assumed that the load may deform the metal plate 10 on the lower side. The number of sheets is preferably about 10 to 20.

Next, a holding jig for holding the plurality of metal plates 10 arranged on the lower plate 12 will be described. Figure 2
As shown in (a) and (b), the holding jig 40 corresponds to the adhesive portion 10z of the metal plate 10 on the lower plate 12 in which the plurality of metal plates 10 are stacked and arranged as described above. The pressing portion 1 of the metal plate 10 is provided with a convex portion 30a
A holding plate 30 having a concave portion 30b is arranged at a portion corresponding to 0x and the rolling portion 10y. As a result, the adhesive portion 10z on the peripheral portion of the metal plate 10 is sandwiched between the peripheral portion of the lower plate 12 and the convex portion 30a of the holding plate 30.

An upper plate 32 is provided on the pressing plate 30. The upper plate 32 is provided with a convex portion 32a on the peripheral portion thereof. Further, side guides 34 sandwiching the upper plate 32 and the lower plate 12 are provided at the start end and the end of the upper plate 32 and the lower plate 12.
Are provided respectively.

Further, an opening 32 is formed at the center of the upper plate 32.
b is formed, and a cap screw 36 is inserted into the opening 32b. By screwing the cap screw 36, the upper plate 3
A predetermined pressing force can be applied to the lower pressing plate 30. The holding plate 30 and the upper plate 32 are also the lower plate 1.
Similar to 2, it is made of super steel or ceramic.

The pressing jig 40 has such a structure, and the adhesive portion 10z of the metal plate 10 is fixed to the convex portion 30 of the pressing plate 30 by screwing the pressing screw 36 to a predetermined position.
It is adapted to be pressed into the a and the peripheral portion of the lower plate 12 by a predetermined pressing force. Moreover, as described with reference to FIG. 1C, the rolling portions 10y of the plurality of metal plates 10 are thinner than the other portions, so that the rolling portions 10y do not come into contact with each other. Therefore, the problem that the rolled portion 10y is unnecessarily pressed and deformed under the influence of the pressure applied to the bonding portion 10z does not occur. At this time, for example, the metal plate 10
The bonded portion 10z of is pressed with a load of 1 g / mm ² .

In the above example, a plurality of metal plates 10 are used.
Although the form in which the metal plates 10 are stacked and pressed by the holding jig 40 is shown, one metal plate 10 may be pressed by the holding jig 40.

Then, the bonding portion 10 is pressed by the holding jig 40.
The metal plate 10 on which z is pressed is heat-treated by a heat treatment device.
As shown in FIG. 3 (a), the heat treatment apparatus 50 used in the present embodiment includes a metal mesh belt conveyor 42 that conveys an object to be heat treated at a predetermined speed, a heat treatment furnace 44, and an upper side in the heat treatment furnace 44. And a belt conveyor furnace basically constituted by heaters 48 arranged on the lower side. A cooling chamber 44a is provided adjacent to the heat treatment furnace 44 on the transport direction side of the heat treatment furnace 44.
A cooling fan 46 is attached to the upper part of the.

A non-oxidizing gas supply pipe 45 and a non-oxidizing gas discharge pipe 47 are provided in the upper part of the heat treatment furnace 44, and the non-oxidizing gas such as nitrogen gas or argon is converted into the non-oxidizing gas. After being supplied into the heat treatment furnace 44 by the supply pipe 45, it is discharged to the outside of the heat treatment furnace 44 by the non-oxidizing gas discharge pipe 47.

The article to be heat treated is conveyed by the belt conveyor 42 from the carry-in section 44x into the heat treatment furnace 44 at a predetermined conveyance speed, and is passed through the heat treatment furnace 44 to undergo a predetermined heat treatment, and subsequently, the cooling chamber 44a. After being cooled by, it is conveyed to the outside from the carry-out section 44y.

Using such a heat treatment furnace 50, the metal plate 10 pressed by the holding jig 40 is heat-treated. The temperature profile in the heat treatment furnace 44 is shown in FIG.
As shown in (b), first, 600 to 8 at a predetermined heating rate.
The temperature is raised to 00 ° C., preferably 700 ° C., and this temperature is maintained for, for example, 1 to 2 hours to perform heat treatment, and then the cooling chamber 44.
In a, the temperature is lowered to, for example, about 150 ° C.

The temperature profile is the set temperature of the heater 48 and the conveying speed of the belt conveyor 42 (for example, 20 to 20).
0 mm / min), and is set by adjusting the flow rate of nitrogen gas and the like. The atmosphere in the heat treatment furnace 44 is preferably a non-oxidizing gas such as nitrogen or argon from the viewpoint of preventing oxidation of the metal plate 10 and suppressing discoloration, but may be an air atmosphere.

Thereafter, the holding jig 40 is moved to the belt conveyor 4
2 is carried out from the cooling chamber 44a to the outside and the temperature is lowered to room temperature, and then the holding jig 40 is disassembled to disassemble the plurality of metal plates 10.
Remove. As described above, as shown in FIG. 4, the metal plate 1 manufactured by the metal plate molding method according to the embodiment of the present invention is manufactured.
0 is produced. The adhesive portion 10z of the metal plate 10 is, for example, 7 when it is pressed by the pressing jig 40 with a predetermined force.
The metal plate 1 is heat-treated at a temperature of about 00 ° C.
Both surfaces including the bonding surface 10s of the bonding portion 10z of 0 are flattened, and the flatness can be set to about 50 μm or less.

As described above, by performing the flattening process according to this embodiment, not only the step due to the stress (internal stress) of the metal plate 10 itself but also the step due to the stress in the press molding is corrected. It is possible to obtain flatness equal to or higher than that of the glass substrate.

As shown in FIG. 5, in the metal plate 10 of this embodiment, the adhesive surface 10 s is provided with the adhesive layer 62 on the peripheral portion of the transparent glass substrate 60 on which the predetermined organic EL element array 64 is formed. It is adhered through to form a back cap (sealing plate). Further, the hygroscopic material 66 is adhered to the bottom surface of the recess 11 of the metal plate 10.

Since the metal plate 10 of the present embodiment has a flatness equal to or higher than that of the glass substrate, the metal plate 10 can be bonded to the glass substrate 60 with good adhesion and high reliability. As a result, moisture is prevented from entering the organic EL element array 102 from the outside, so that the occurrence of display defects in the organic EL display device is prevented.

Further, since the metal plate can be used as the back cap, unlike the case where the glass substrate is used, press molding can suppress the cost increase and the thickness of the back cap. Since a sufficient mechanical strength can be obtained even if the thickness is reduced, a thin organic EL display device can be easily manufactured.

Further, as the material of the metal plate 10, Ni--Fe having a thermal expansion coefficient similar to that of the glass substrate 60 of the display device.
By using an alloy or the like, the reliability of bonding due to stress such as heat can be further improved as in the case of using a glass substrate.

The inventor of the present application conducted an experiment for confirming the effect of the metal sheet forming method of this embodiment. 6 is a plan view showing an experimental sample, FIG. 7 shows the flatness of the surface of the metal plate before the flattening treatment, and FIG. 8 shows the flattening treatment according to the metal plate forming method of the present embodiment. FIG. 9 shows the flatness of the surface of the metal plate, and FIG. 9 shows the flatness of the surface of the metal plate which is also subjected to the flattening treatment after bending the metal plate.

First, as shown in FIG. 6, by etching a metal plate made of a Ni--Fe alloy, the ring-shaped metal plate 1 corresponding to the above-mentioned bonded portion 10z of the metal plate 10 is etched.
0b was prepared as an experimental sample. Then, the flatness (flatness) of a minute area (X axis × Y axis) on the surface of the ring-shaped metal plate 10b was measured by a non-contact step measuring device.

As shown in FIGS. 7 (a) to 7 (c), three minute regions on the surface of the ring-shaped metal 10b are ±.
It was confirmed that a step difference of about 10 μm was generated. This is a step generated by the stress (internal stress) of the metal plate itself. In general, since the flatness is proportional to the square of the area, the area of the adhesive portion 10z of the metal plate 10 is considerably larger than the area of the above-mentioned minute area for measurement. It is easily understood that it exceeds.

Subsequently, in order to confirm the effect of the flattening treatment according to the metal plate forming method of this embodiment, the ring-shaped metal plate 10 is attached to the holding jig 40 by the same method as described above.
A flattening process was performed by performing a heat treatment in a state where b was incorporated and pressed.

According to this result, as shown in FIGS. 8 (a) to 8 (c), the step difference is suppressed to about ± 5 μm or less in each of the above-mentioned three minute regions, and the metal plate of the present embodiment is suppressed. It was confirmed that the molding method of 1 is effective for improving the flatness of the surface of the metal plate.

When the hardness of the surface of the ring-shaped metal plate 10b subjected to the flattening treatment was measured by a Pickers hardness tester, the pickers hardness (Hv) before the flattening treatment was about 210. 190 after the flattening process
It was decreasing to some extent. This means that the stress (internal stress) of the ring-shaped metal plate 10b is removed and the ring-shaped metal plate 10b is flattened.

Next, the inventor of the present application intentionally bends the ring-shaped metal plate 10b shown in FIG. 6 and then performs a flattening process by the metal plate forming method of this embodiment. This is because the flatness of the surface of the metal plate is not only determined by its own stress (internal stress) but also deteriorates by the stress during press molding.

As shown in FIG. 9A, when the ring-shaped metal plate 10b was stressed and bent, a step having an absolute value of about 120 μm was formed on the upper side. As a result of performing a flattening process on this by the same method as described above, as shown in FIG.
As shown in (b) or (c), on the contrary, although a step of about 15 μm was formed on the lower side, it was confirmed that the flatness was effectively improved. It should be noted that FIG. 9C is a graph in which the vertical axis (flatness) of FIG. 9B is adjusted to the vertical axis (flatness) scale of FIGS. 7 and 8.

(Second Embodiment) FIG. 10 is a sectional view showing a method for forming a metal plate according to a second embodiment of the present invention. The difference between the second embodiment and the first embodiment is that the plurality of metal plates 10 are incorporated in the holding jig 40 in a state in which spacers are inserted between the adhesive portions 10z thereof. Other steps are the same as those in the first embodiment, and thus detailed description thereof will be omitted.

As described above, in the first embodiment, when a plurality of metal plates 10 are stacked, the pressing portions 10x are in contact with each other. Therefore, when the number of metal plates 10 to be stacked is large, the load is particularly large. It is assumed that the lower metal plate 10 is deformed. The metal plate forming method of the second embodiment eliminates such a problem.

In the method of forming the metal plate of the second embodiment, first, the same metal plate 10 as shown in FIG. 1B is prepared by the same method as in the first embodiment. After that, as shown in FIG. 10, the plurality of metal plates 10 are stacked with the spacers 70 inserted between the adhesive parts 10z. The spacer 70 is made of super steel, ceramics, or the like, and has a ring shape corresponding to the adhesive portion 10z of the metal plate.

At this time, the adhesive parts 10 of the plurality of metal plates 10
Since the spacer 70 is disposed between z, the pressing portion 10x of the metal plate 10 is disposed above by the thickness of the spacer 70. As a result, in the plurality of metal plates 10, not only the gap 13 exists between the rolled portions 10y,
A gap 13a also exists between the pressing portions 10x, and unlike the first embodiment, no contact is made except for the adhesive portion 10z.

The metal plates 10 are stacked in this manner, and then the bonding portion 1 of the metal plates 10 is manufactured in the same manner as in the first embodiment.
The metal plate 10 to be the back cap is manufactured by performing heat treatment while pressing 0z with a predetermined force.

According to the metal plate forming method of the second embodiment, even if a large number of metal plates are stacked, the adhesive portion 1
Since the metal plates 10 do not come into contact with each other except 0z, there is no possibility that the stacked metal plates are deformed. For this reason, for example, 100 or more metal plates 10 can be stacked, assembled into the holding jig 40, and heat-treated collectively, and the manufacturing efficiency can be improved.

(Third Embodiment) FIG. 11 is a sectional view showing a method for forming a metal plate according to a third embodiment of the present invention. The difference between the third embodiment and the second embodiment is that when a plurality of metal plates 10 are stacked, a spacer is not used and portions other than the adhesive portion 10z of the metal plate 10 do not come into contact with each other. . Other steps are the same as those in the first embodiment, and thus detailed description thereof will be omitted.

As described above, in the first embodiment, when a plurality of metal plates 10 are stacked, it is assumed that the metal plates 10 are deformed by the load. The metal plate forming method of the third embodiment eliminates such a problem without inserting a spacer.

In the method of forming a metal plate according to the third embodiment, first, as shown in FIG. 11A, a metal plate 10a having a film thickness of about 0.25 to 0.3 mm similar to that of the first embodiment is formed. prepare. Then, as shown in FIG.
A pattern (not shown) of a resist film is formed on a predetermined portion of the peripheral edge to be the adhesion part of, and the metal plate is etched by about 50 to 150 μm by wet etching using the resist film as a mask.

Next, as shown in FIG. 11 (c), a die 26x equipped with a punch 20, a pressing member 22 and a die 24.
To prepare. Then, the metal plate 10a is inserted into the mold 26x so that the etched surface of the metal plate 10a faces the punch 20, and the punch 20 presses the metal plate 10a. As a result, as shown in FIG. 11D, the etched portion of the metal plate 10a is pressed, and the pressing portion 10x and the rolling portion 1 are pressed.
0y is formed, and as a result, the concave portion 11 is formed.

Then, as shown in FIG. 11 (e), the first
The lower plate 12 of the holding jig 40 is manufactured by the same method as that of the embodiment.
A plurality of metal plates 10 are stacked on top. At this time, the metal plate 1
Since the rolling portion 10y and the pressing portion 10x of 0 have been etched in advance and the thickness thereof is thinner than that of the adhesive portion 10z,
As shown in the figure, the rolling portions 10y and the pressing portions 10x of the plurality of metal plates 10 do not contact each other, and the gap 13,
13a will be present respectively.

In this way, a plurality of metal plates 10 are stacked, and then heat treatment is performed in the same manner as in the first embodiment while pressing the adhesive portion 10z of the metal plates 10 with a predetermined force to form a back cap. The following metal plate 10 is manufactured.

According to the third embodiment, similar to the second embodiment, even if a large number of metal plates are stacked, the adhesive portion 10z is formed.
Since it is prevented from contacting other than the above, there is no possibility of causing a problem such as deformation of the metal plate. Thereby, for example, 100 or more metal plates 10 are stacked and the holding jig 40
It becomes possible to heat-treat in a batch by incorporating into.

Moreover, unlike the second embodiment, since it is not necessary to insert the spacer between the plurality of metal plates 10, the work when incorporating the plurality of metal plates 10 into the holding jig 4 is simplified. The manufacturing efficiency can be further improved.

(Fourth Embodiment) FIG. 12 is a sectional view showing a method for forming a metal plate according to a fourth embodiment of the present invention. The difference between the metal plate forming method of the fourth embodiment and the first to third embodiments is that the recesses are formed in the metal plate by etching without using press forming.

In the first to third embodiments, the mode in which a thin metal plate (for example, 0.25 to 0.3 mm) is used is illustrated, but a thick metal plate (for example, 0.7 to 0. 8
mm) is difficult to process by press molding,
In the fourth embodiment, the recess is formed by half-etching the metal plate in the thickness direction.

In the method of forming a metal plate according to the fourth embodiment, first, as shown in FIG.
A metal plate 10 of about 0.8 mm is prepared. Then, Figure 1
As shown in FIG. 1B, a resist film 15 is patterned on a predetermined peripheral portion of the metal plate 10 to be an adhesive portion, and the metal plate 10 is etched by wet etching using the resist film 15 as a mask. By this. 0.5m depth
The recess 11 of about m is formed and the adhesive portion 10z is defined.

Then, as shown in FIG. 11D, the first
By a method similar to that of the embodiment, the metal plate 10 is assembled into the holding jig 40 so that the bonding surface 10s faces the lower plate 12. Then, heat treatment is performed in a state in which the adhesive portions 10z of the plurality of metal plates 10 are pressed with a predetermined force, and thus the metal plate 10 to be the back cap is manufactured.

In the fourth embodiment, a thick metal plate can be easily applied as a back cap of an organic EL display device. Further, as in the second and third embodiments, even if many metal plates are stacked, the adhesive portion 1
Since there is no contact except for 0z, there is no possibility of causing a problem such as deformation of the metal plate. This gives, for example, 10
It becomes possible to stack zero or more metal plates 10 and incorporate them into the holding jig 40 to perform heat treatment collectively. Moreover, unlike the second embodiment, it is not necessary to insert a spacer between the adhesive portions 10z of the plurality of metal plates 10.

[0080]

As described above, according to the present invention,
Prepare a metal plate that has a concave shape in the central main part other than the peripheral part, stack a plurality of metal plates with the peripheral parts corresponding to each other, and perform heat treatment while applying a predetermined pressure to the peripheral part I have to.

By doing so, the stress (internal stress) of the metal plate itself is exerted on the surface of the peripheral portion of the metal plate.
It is possible to correct not only the step due to the above, but also the step caused by the stress in the press molding, and the flatness equal to or more than that of the glass substrate can be obtained.

Therefore, when this metal plate is used as a back cap of a display device, the reliability of bonding with the substrate of the display device can be improved, and as a result, moisture can be prevented from entering the element and display defects can be prevented. Is prevented from occurring. Further, since it becomes possible to use a metal plate, unlike the case where a glass substrate is used, cost increase can be suppressed and sufficient mechanical strength can be obtained even if the thickness of the back cap is reduced. Therefore, a thin display device can be easily manufactured.

[Brief description of drawings]

1 (a) to 1 (c) are cross-sectional views showing a method for forming a metal plate according to a first embodiment of the present invention, and FIG. 1 (b) is shown in FIG.
It is sectional drawing along II of b).

FIG. 2 (a) is a perspective view showing an example of a holding jig used in the method for forming a metal plate according to the embodiment of the present invention, FIG.
2B is a sectional view taken along line II-II of FIG.

FIG. 3 (a) is a cross-sectional view showing an example of a heat treatment apparatus used in the metal sheet forming method of the embodiment of the present invention, FIG.
3B shows an example of the temperature profile in the furnace of the heat treatment apparatus of FIG.

FIG. 4 is a cross-sectional view showing a metal plate (back cap) manufactured by the metal plate molding method according to the first embodiment of the present invention.

FIG. 5 is a sectional view showing an example of an organic EL display device to which the metal plate according to the first embodiment of the present invention is applied as a back cap.

FIG. 6 is a plan view showing an experimental sample.

FIG. 7 shows the flatness of the surface of the metal plate before the flattening treatment.

FIG. 8 shows the flatness of the surface of the metal plate which has been subjected to the flattening treatment according to the metal plate forming method of the present embodiment.

FIG. 9 shows the flatness of the surface of a metal plate which has been subjected to a flattening treatment according to the method for forming a metal plate of the present embodiment after bending the metal plate.

FIG. 10 is a sectional view showing a method for forming a metal plate according to a second embodiment of the present invention.

FIG. 11 is a cross-sectional view showing a method for forming a metal plate according to a third embodiment of the present invention.

FIG. 12 is a cross-sectional view showing a method for forming a metal plate according to a fourth embodiment of the present invention.

FIG. 13 is a cross-sectional view showing an example of an organic EL display device.

[Explanation of symbols]

10a, 10 ... Metal plate, 10x ... Pressing part, 10y ... Rolling part, 10z ... Adhesive part (predetermined peripheral portion), 10s ... Adhesive surface, 1
1, 30b, ... Recesses, 12 ... Lower plate, 13, 13a ... Gap, 20 ... Punch, 22 ... Holding member, 24 ... Die, 2
6, 26x ... Mold, 30 ... Holding plate, 30a, 32a ... Convex portion, 32 ... Upper plate, 34 ... Side guide, 36 ... Holding screw,
40 ... Holding jig, 42 ... Belt conveyor, 44 ... Heat treatment furnace, 44x ... Carry-in section, 44y ... Carry-out section, 45 ... Pipe for supplying non-oxidizing gas, 46 ... Cooling fan, 47 ... Pipe for discharging non-oxidizing gas , 48 ... Heater, 50 ... Heat treatment device, 60
... Glass substrate, 62 ... Adhesive layer, 64 ... Organic EL element array, 66 ... Hygroscopic material, 70 ... Spacer.

Claims (8)

[Claims] 1. A step of preparing a metal plate in which a central main portion other than the peripheral edge predetermined portion has a concave shape, and a plurality of the metal plates are stacked so that the peripheral edge predetermined portions correspond to each other, and the peripheral edge predetermined portion is stacked. And a step of performing a heat treatment in a state of pressing the metal plate. 2. A step of preparing a metal plate having a concave main portion other than the predetermined peripheral portion, and a step of heat-treating while pressing the predetermined peripheral portion of the metal plate. Metal plate forming method. 3. The step of preparing the metal plate is a step of forming the concave shape by pressing a central main portion of the metal plate by press molding.
Or the method for forming a metal plate according to 2. 4. The step of preparing the metal plate comprises the steps of etching the central main part of the metal plate to reduce the thickness, and pressing the central main part of the metal plate by press molding to form the concave shape. The method for forming a metal plate according to claim 1 or 2, further comprising a step of forming. 5. The step of preparing the metal plate is a step of forming the concave shape by etching the central main part of the metal plate to reduce the thickness. The method for forming a metal plate according to. 6. The method of forming a metal plate according to claim 1, wherein, in the step of performing the heat treatment, the plurality of metal plates are stacked with a spacer interposed between predetermined portions of the peripheral edge of the plurality of metal plates. 7. The metal plate is an alloy of nickel (Ni) and iron (Fe), an alloy of nickel (Ni), iron (Fe) and cobalt (Co), tungsten (W) and molybdenum (Mo). The method for forming a metal plate according to any one of claims 1 to 6, comprising any one selected from the group. 8. The method for forming a metal plate according to claim 1, wherein the heat treatment is performed at a temperature of 600 to 800 ° C.