TWI718484B - Manufacturing method of display device - Google Patents

Abstract

The present invention provides a method for easily separating the resin substrate from the support after forming a designated display portion for a resin substrate that has been integrated with a support in advance, so that a display device can be simply manufactured.

The manufacturing method of the display device of the present invention is characterized in that the first resin layer and the second resin layer are laminated on the support, and a designated display portion is formed on the second resin layer, and then the first resin layer is separated The interface with the second resin layer is a display device equipped with a display portion on a resin substrate made of the second resin layer.

Description

Manufacturing method of display device

The present invention relates to a method of manufacturing a display device, and more specifically, to a method of manufacturing a display device having a display portion formed on a resin substrate, such as a liquid crystal display device or an organic EL display device.

Display devices such as liquid crystal display devices or organic EL display devices are used in various display applications such as large displays for televisions, or small displays for mobile phones, laptop computers, and smart phones. A typical display device is an organic EL display device. For example, in the organic EL display device, a thin film transistor (hereinafter referred to as TFT) is formed on a glass substrate supporting a substrate, and an electrode, a light-emitting layer, and an electrode are sequentially formed. Glass substrates, multilayer films, etc. are produced by gas-sealing.

Here, by replacing the glass substrate supporting the base material with a conventional glass substrate with a resin base material, thinness can be achieved. Lightweight. Flexible, can further expand the use of the display device. However, in general, when resin is compared with glass, due to poor dimensional stability, transparency, heat resistance, moisture resistance, gas barrier properties, etc., various reviews are currently being conducted in the research phase.

For example, Patent Document 1 relates to the invention of polyimide and its precursors useful as plastic substrates for flexible displays, and reports the use of tetracarboxylic acids containing alicyclic structures such as cyclohexylphenyltetracarboxylic acid. , Polyimide formed by reaction with various diamines, excellent transparency. In addition, the use of flexible resins on the support substrate has been tried to reduce the weight. For example, the following Non-Patent Documents 1 and 2 propose organic EL display devices using highly transparent polyimide on the support substrate. .

It is known that the polyimide and other resin films are extremely useful in plastic substrates for flexible displays. However, glass substrates are already used in the manufacturing steps of display devices, and most of the production equipment is designed to use glass substrates. . Therefore, it is preferable that the existing production equipment can be effectively utilized and the display device can be produced at the same time.

There is known a method for manufacturing a display device with a resin film laminated on a glass substrate, completing a specified manufacturing step of a display device, then taking out the glass substrate, and having a display portion on the resin substrate (refer to Patent Literature 2. Non-Patent Document 3 and Non-Patent Document 4) as one of the specific examples of the review. Therefore, in such a manufacturing method, it is necessary to separate the resin base material and the glass so as not to damage the display part (display part) formed on the resin base material.

In other words, Non-Patent Document 3 uses a method called EPLaR (Electronics on Plastic by Laser Release) to irradiate thunder from the glass side after forming a designated display portion on a glass substrate coated with a resin substrate. The resin substrate with the display part is forcibly separated from the glass. However, in this way, not only an expensive laser device must be used, but also the separation is extremely time-consuming and has the disadvantage of low productivity. In addition, the surface properties of the resin substrate may be adversely affected during separation, or the display portion mounted on it may be adversely affected.

In addition, the method described in Non-Patent Document 4 is a method that has improved the disadvantages of the EPLaR method. After coating and forming a release layer on a glass substrate, a polyimide resin is applied to the release layer to complete the organic EL display. A method of peeling the polyimide film layer from the peeling layer after the manufacturing steps of the device. Here, FIG. 1 and FIG. 2 show a method of manufacturing an organic EL display device described in Non-Patent Document 4. This method refers to the formation of the peeling layer 2 on the glass substrate 1, the polyimide layer 3 is formed in a larger area than the peeling layer 2, and then the specified TFT and organic EL steps are processed to form TFT/organic After the EL panel portion (display portion) 4, cut along the cutting line 5 inside the peeling layer 2 to the peeling layer 2, and peel off the polyimide layer 3 and the TFT/organic EL panel portion (display portion) from the peeling layer 2. 4. Furthermore, Non-Patent Document 4 does not specifically describe what kind of release layer is used. Therefore, the actual degree of peeling force required for separation from the peeling layer and the state of the surface properties of the polyimide layer 3 to be separated are unclear. In addition, since the area of the peeling layer must be smaller than the area of the polyimide layer, the area where the organic EL display device can be formed is limited, which becomes a production issue. In order to prevent the reduction of productivity, the area of the peeling layer is increased, and the area of the polyimide layer attached to the glass at the outer periphery of the peeling layer is reduced, and the problem of peeling is likely to occur due to the stress in the step.

In addition, the method described in Patent Document 2 is to form a peeling layer made of parylene or a cyclic olefin copolymer on a glass substrate, and then form a relatively peeling layer in the same manner as the method described in Non-Patent Document 4. A method of peeling off the polyimide layer after making an electronic display on a larger circle of polyimide layer. Generally speaking, an annealing step up to about 400°C must be carried out when forming TFTs required for video display applications. However, this method has poor heat resistance of the peeling layer than that of polyimide, so it will be more difficult for the polyimide layer. The heat treatment temperature or the maximum temperature when the electronic display is made is limited by the heat resistance of the peeling layer. Furthermore, since the adhesive force between the glass and the peeling layer and between the peeling layer and the polyimide layer is weak, it becomes a cause of peeling that cannot endure the stress in the step. In addition, the thermal expansion coefficient of the peeling layer is larger than that of polyimide, and the difference in thermal expansion coefficient due to different resin types is a major cause of warpage.

In addition, Patent Document 3 describes a method of manufacturing a semiconductor device in which the support substrate is peeled from the resin film after the semiconductor element is formed on the support substrate by forming the upper layer of the resin film formed by the peeling layer. This Patent Document 3 discloses polybenzoxazole as a resin film. Generally speaking, when polybenzoxazole is compared with polyimide, it has better peelability with other materials. Here, in order to ensure good peelability with other materials, the heat treatment time is preferably short when the adherend is attached. However, in the case of polyimide benzoxazole, due to heterocyclic ring and aromatic The ring forms a coplanar structure, which tends to increase the crystallinity. In order to sufficiently reduce the concentration of volatile components remaining in the reacted film, it is necessary to perform the heat treatment at a high temperature and a long time. In addition, the degree of force required for separation from the peeling layer is not clear in this Patent Document 3. It is disclosed that the peeling layer and the resin film can be peeled off by immersing in warm water. In addition, since the crystallinity is high, the film tends to become brittle. In order to prevent this, the introduction of an alicyclic structure with a soft structure may cause a problem of reduced heat resistance. Moreover, due to the introduction of an alicyclic structure, the thermal expansion property is also less likely to decrease.

The methods described in these patent documents 2 to 3 and non-patent documents 3 to 4 all use glass as a support. By forming a display portion on a resin substrate fixed to the glass, the processing of the resin substrate can be guaranteed It has the advantage that the glass substrate can be directly used in the current manufacturing line of display devices such as liquid crystal display devices or organic EL display devices. Therefore, after the designated display part is formed, it can be separated extremely easily without adversely affecting the resin substrate or the display part. Not only can it become a method with excellent mass productivity, but it can also promote the use of a resin substrate. Replace the glass substrate.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2008-231327 A

[Patent Document 2] JP 2010-67957 A

[Patent Document 3] JP 2009-21322 A

[Non-Patent Literature]

[Non-Patent Document 1] S. An et. al., "2.8-inch WQVGA Flexible AMOLED Using High Performance Low Temperature Polysilicon TFT on Plastic Substrates", SID2010 DIGEST, p706(2010)

[Non-Patent Document 2] Oishi et. Al., "Transparent P1 for flexible display", IDW’11 FLX2/FMC4-1

[Non-Patent Document 3] E. I. Haskal et. al. "Flexible OLED Displays Made with the EPLaR Process", Proc. Eurodisplay ’07, pp. 36-39 (2007)

[Non-Patent Document 4] Cheng-Chung Lee et. al. ”A Novel Approach to Make Flexible Active Matrix Displays”, SID10 Digest, pp. 810-813(2010)

Therefore, the object of the present invention is to provide a method for easily separating the resin substrate from the support after forming a designated display portion for a resin substrate that has been integrated with a support in advance, so that a display device can be simply manufactured .

In order to solve the above-mentioned problems, the inventors of the present invention conducted an examination and found that the first resin layer and the second resin layer were laminated on the support to form a designated display portion on the second resin layer, and then the second resin layer was separated. The boundary surface between the first resin layer and the second resin layer can be manufactured extremely simply on a resin substrate formed by the second resin layer as a display device with a display portion, thus completing the present invention.

In other words, the gist of the present invention is as follows.

(1) A method of manufacturing a display device, which is characterized by forming a designated display portion on the second resin layer in a state where the first resin layer and the second resin layer are laminated on the support, and then separating the first resin layer The interface with the second resin layer is a display device equipped with a display portion on a resin substrate made of the second resin layer.

(2) The method for manufacturing a display device as described in (1), which involves directly laminating a first resin layer and a second resin layer on a laminated film and a support, using the first resin layer of the aforementioned laminated film and One side of the aforementioned support is formed by laminating the laminate film with a designated display portion, and then separating the boundary surface between the first resin layer and the second resin layer, and the resultant surface is formed by the second resin layer. On the resin substrate is a display device equipped with a display unit.

(3) The method for manufacturing a display device as described in (2), wherein the first resin layer and the second resin layer constituting the laminated film are each made of polyimide.

(4) The method for manufacturing a display device as described in (1), which is to form a first polyimide layer and a second polyimide layer on a support, and then further form a designated display portion, and then separate the first polyimide layer and the second polyimide layer. The boundary surface between a polyimide layer and a second polyimide layer is prepared on a polyimide substrate formed by the second polyimide layer as a display device with a display portion.

(5) The method for manufacturing a display device as described in (4), wherein after the designated display portion is formed, the support is removed, and the boundary surface between the first polyimide layer and the second polyimide layer is separated to prepare a polyimide layer. On the imide substrate is a display device equipped with a display unit.

(6) The method for manufacturing a display device as described in (4) or (5), wherein the first polyimide layer is formed by laminating a polyimide film, and the first polyimide layer is formed by coating polyimide or polyimide The resin solution of the amine precursor forms the second polyimide layer.

(7) The method for manufacturing a display device as described in (4) or (5), wherein the first polyimide layer is formed by coating and heating a resin solution of polyimide or a polyimide precursor And the second polyimide layer.

(8) The method for manufacturing a display device as described in any one of (4) to (7), wherein a part of the second polyimide extends outward from the periphery of the first polyimide layer, and The outward extending part of the second polyimide layer is fixed and attached to the support.

(9) The method for manufacturing a display device as described in any one of (4) to (7), wherein part of the single layer of the first polyimide layer or the second polyimide layer is compared with other layers The peripheral edge portion extends outward.

(10) The method for manufacturing a display device as described in any one of (4) to (9), wherein the first resin layer is separated from the second resin layer after scoring is placed in the first resin layer along the outer periphery of the display portion Resin layer.

(11) The method for manufacturing a display device as described in (6) or (7), wherein the second polyimide is formed by coating a resin solution of polyimide or a polyimide precursor and then heating When layering, the high temperature retention time of the second polyimide layer is less than 60 minutes.

(12) The method for manufacturing a display device as described in any one of (1) to (11), wherein the support is a glass substrate.

(13) The method for manufacturing a display device according to any one of (1) to (12), wherein the thermal expansion coefficient of the first resin layer is 25 ppm/K or less.

(14) The method for manufacturing a display device according to any one of (1) to (13), wherein the thermal expansion coefficient of the second resin layer is 25 ppm/K or less.

(15) The method for manufacturing a display device according to any one of (1) to (14), wherein the transmittance of the second resin layer in the wavelength range of 440 nm to 780 nm is 80% or more.

(16) The method for manufacturing a display device as described in any one of (1) to (15), wherein the display portion is formed via a gas barrier layer, and the difference in thermal expansion coefficient between the second resin layer and the gas barrier layer is 10 ppm/ Below K.

(17) The method for manufacturing a display device according to any one of (1) to (16), wherein the display portion is a color filter layer.

(18) The method for manufacturing a display device according to any one of (1) to (17), wherein the peel strength of the first resin layer and the second resin layer is 200 N/m or less.

(式中，Ar₁係表示具有芳香環之4價有機基，Ar₂係表示以下述一般式(2)或(3)所示之2價有機基)。 (19) The method for manufacturing a display device as described in any one of (1) to (18), wherein at least one of the first resin layer and the second resin layer has a structure represented by the following general formula (1) The unit is made of polyimide,

(In the formula, Ar ₁ represents a tetravalent organic group having an aromatic ring, and Ar ₂ represents a divalent organic group represented by the following general formula (2) or (3)).

(式中，一般式(2)或一般式(3)之R₁~R₈係互相獨立地表示氫原子、氟原子、碳數1~5之烷基或烷氧基、或氟取代烴基，於一般式(2)之R₁~R₄中或一般式(3)之R₁~R₈中至少一個為氟原子或氟取代烴基)。

_{(In the formula, R 1} to R ₈ of general formula (2) or general formula (3) independently represent a hydrogen atom, a fluorine atom, an alkyl or alkoxy group with 1 to 5 carbon atoms, or a fluorine-substituted hydrocarbon group, At least one of R ₁ to R ₄ in general formula (2) or R ₁ to R ₈ in general formula (3) is a fluorine atom or a fluorine-substituted hydrocarbon group).

According to the present invention, by laminating the first resin layer and the second resin layer on the support, the handleability or dimensional stability can be ensured, and at the same time, a designated display portion can be formed. After the display part is formed, especially without laser irradiation, it can be easily separated by using the interface between the first resin layer and the second resin layer, so the display device can be manufactured very simply. Moreover, after separation, the second resin layer that becomes the resin substrate or the display part will not be adversely affected, and the support will not be damaged. Therefore, the support can be reused when manufacturing the display device, and the display can be greatly improved. To reduce the original manufacturing price.

1‧‧‧Glass substrate

2‧‧‧Peeling layer

3‧‧‧Polyimide layer

4‧‧‧Display (TFT/Organic EL Panel)

5‧‧‧Cut the line

6‧‧‧Next layer

7‧‧‧The first polyimide layer

8‧‧‧Second polyimide layer

9‧‧‧Cut off area

10‧‧‧Cut off

[Figure 1] Figure 1 is a schematic diagram illustrating a method of manufacturing an organic EL display device according to the prior art.

[Fig. 2] Fig. 2 is a schematic diagram illustrating a manufacturing method of a conventional organic EL display device.

[Fig. 3] Fig. 3 is a schematic diagram illustrating the manufacturing method of the display device of the present invention.

[Fig. 4] Fig. 4 is a schematic diagram for explaining the manufacturing method of the display device of the present invention.

[FIG. 5] FIG. 5 is a schematic diagram (partially enlarged view) explaining the manufacturing method of the display device of the present invention.

[Fig. 6] Fig. 6 is a schematic diagram illustrating the manufacturing method of the display device of the present invention.

[FIG. 7] FIG. 7 is a schematic diagram illustrating the manufacturing method of the display device of the present invention.

[Fig. 8] Fig. 8 is a schematic diagram illustrating the manufacturing method of the display device of the present invention.

[FIG. 9] FIG. 9 is a schematic diagram illustrating the manufacturing method of the display device of the present invention.

[For the implementation of the invention]

In the following, the present invention will be explained in more detail with reference to the drawings, but the present invention is not limited by the following description.

The manufacturing method of the display device of the present invention is characterized in that the first resin layer and the second resin layer are laminated on the support to form a designated display portion on the second resin layer, and then the first resin layer and the second resin layer are separated. The boundary surface of the second resin layer is a display device equipped with a display portion on a resin substrate formed of the second resin layer. In more detail, as described below. Moreover, in the following preferred examples, both the first resin layer and the second resin layer are made of polyimide, but at least one resin layer can also be formed of resins other than polyimide.

The manufacturing method of the display device of the present invention uses a support having a first polyimide layer and a second polyimide layer in advance. Secondly, by forming a designated display portion on the side of the second polyimide layer, and then separating the boundary surface between the first polyimide resin layer and the second polyimide resin layer, the On the resin substrate (polyimide substrate) formed by the polyimide layer is a display device equipped with a display portion.

More specifically, first, as shown in FIG. 3, the support 1 of the pedestal is prepared by the manufacturing steps of the display portion of the liquid crystal display device or the organic EL display device. The support 1 is not particularly limited as long as it has chemical strength or mechanical strength such as heat resistance or gaseous environment during the manufacturing process of forming the display portion of various display devices, such as a glass substrate or a metal substrate, Preferably, a glass substrate can be used. The glass substrate can be used by general users when manufacturing an organic EL display device, for example. However, in the display device manufactured by the present invention, the support matrix of the display part is a polyimide substrate formed by the second polyimide layer 8. In short, the glass substrate referred to here serves as a pedestal when the display part is formed on the polyimide base material, even if the polyimide base material is guaranteed to be rational or dimensional stability during the manufacturing process of the display part Etc., it will be removed in the end, and it is not the one who constitutes the display device. Moreover, when the support is used to control the releasability of the first polyimide layer 7 or the second polyimide layer 8, surface treatment may also be performed.

In the present invention, a first polyimide layer and a second polyimide layer are arranged on the support 1. The method includes 1) pre-laminating the first polyimide layer and the second polyimide layer, And the method of laminating the laminated polyimide laminated film on the support (layering method), 2) by coating polyimide or polyimide precursor (hereinafter also referred to as "polyimide The method of forming the first polyimide layer and the second polyimide layer (coating method) by using a resin solution of “amino acid”), 3) by laminating a polyimide film on a support to form the first polyimide layer Polyimide layer, and coating polyimide or polyimide precursor resin solution to form any one of the methods (combined usage) of the second polyimide layer. In addition, the support 1 and the first polyimide layer here may be directly bonded and laminated, or may be laminated via an adhesive layer as shown in FIG. 3.

Moreover, in the present invention, at least part of any one of the first polyimide layer and the second polyimide layer can also be formed in a manner that extends outwardly more than the peripheral portion of the other layers. By providing a part of the polyimide layer that is thinner than the part forming the display part on the outer peripheral part, the stress generated in the step can be dispersed, and the support and the polyimide layer can be prevented during the step. There is a peeling situation. The extending distance is not particularly limited, so that the thickness at which the first polyimide layer and the second polyimide layer are bonded is preferably at least 10 times the total thickness.

In the following, the three methods mentioned above are explained individually.

<Layer legal>

Figure 3 shows a state where the polyimide laminated film is attached to the support 1 via the adhesive layer 6 and then the display part is laminated. Here, the polyimide laminated film is formed by the first polyimide layer 7 and the second polyimide layer 8, and can be formed by directly laminating the first polyimide layer 7 and the second polyimide layer 7 and 8. The structure of the polyimide layer 8. To prepare the polyimide laminate film, for example, a polyimide film that becomes the first polyimide layer 7 is coated with a polyimide resin solution that becomes the second polyimide layer 8 , And then dried and imidized by heat treatment (casting method). In addition to resin-based adhesives such as epoxy resin or acrylic resin, the adhesive layer 6 can be an adhesive film with adhesive layers provided on both sides of the support film. In addition, the adhesive layer 6 is used in FIG. 3, and as shown in FIG. 7, the first polyimide layer 7 side can be directly attached to the support 1 by means such as heating and pressing.

Here, the thickness of the second polyimide layer 8 constituting the laminated film is preferably 3 μm or more and 50 μm or less. When the thickness of the second polyimide layer 8 is less than 3μm, it is not easy to ensure the prevention of damage to the resin layer due to the electrical insulation of the resin substrate forming the display device or external factors. On the contrary, if it exceeds 50μm, it may be It will reduce the flexibility and transparency of the display device. In addition, since the first polyimide layer 7 is not one that directly constitutes the display device, when considering its rationality as a laminated film, it is preferably 10 μm or more. The upper limit of the thickness is not particularly limited, but in consideration of cost and the like, it is preferably 100 μm or less.

As described above, the polyimide laminated film is integrated on the support 1 with or without the adhesive layer 6, and then moves to the step of forming the display portion. Here, it refers to the steps when the display is formed. For example, in the case of an organic EL display device, it refers to the program processing of the designated TFT/organic EL step, whereby the formed organic EL element including TFT, electrode, light-emitting layer, etc. is equivalent于Display Department. Here, it is also proposed to form an organic EL that displays colors by combining a color filter with an organic EL that emits white light. The color filter is manufactured in a different step from the TFT/organic EL process, and then is manufactured by bonding to the TFT/organic EL side. The color filter is also equivalent to the display section. In addition, in the case of a liquid crystal display device, it refers to the program processing of the TFT step, whereby the formed TFT, driving circuit, color filters, etc., as required are equivalent to the display portion. In other words, the steps of forming the display part refer to various display devices including electronic paper or MEMS displays, in addition to organic EL display devices or liquid crystal display devices. In the past, various functional layers formed on a glass substrate were formed on the designated playback device. The steps of necessary parts for video (animation or portrait), including the parts obtained therefrom, are collectively called the display part. Through this step, it is laminated on the side of the second polyimide layer 8 that has been integrated with the first polyimide layer 7. The display portion 4 is formed. Next, after the lamination step of all the display parts is completed, the cutting step of cutting the designated size is performed.

Among them, Fig. 4 shows the cutting step. In the present invention, the cutting step is not required, and it can be implemented arbitrarily depending on the form of the manufactured device or the step. In the case of manufacturing an organic EL display device as an example, the cutting is along the cutting line 5 shown in Figure 4, and is completely carried out to the display part (TFT/organic EL panel part) 4 and the second polyimide layer 8. At this time, as shown in FIG. 5, which is an enlarged view of the cutting area 9 shown in FIG. 4, a cutting line 10 is cut to the vicinity of the center of the first polyimide layer 7 and along the display portion at the same time On the outer periphery, when a score is placed on the first resin layer, the TFT/organic EL panel section 4 will not be mechanically damaged, and the second polyimide layer 8 can be reliably and easily separated from the first polyimide layer. The boundary surface of layer 7 is separated.

Here, in order for the second polyimide layer 8 to be easily separated from the boundary surface with the first polyimide layer 7, it is necessary to form a state where the polyimide boundary surface can be easily peeled off. The method is not particularly limited. For example, at least one of the first or second polyimide layers uses polyimide with a specific chemical structure.

Generally speaking, polyimide is usually obtained by polymerizing the acid anhydride and diamine of the raw material, and is represented by the following general formula (1).

In the formula, Ar ₁ represents the tetravalent organic group of the acid anhydride residue, and Ar ₂ represents the divalent organic group of the diamine residue. In terms of heat resistance, at least one of _{Ar 1} and Ar _{2 is more aromatic} good.

The polyimide resin suitable for use in the first polyimide layer or the second polyimide layer of the present invention, for example, polyimide having the following repeating structural units.

更佳者為具有下述重複構造單位之聚醯亞胺。

More preferably, it is a polyimide having the following repeating structural unit.

Furthermore, in addition to these, for example, fluorine-containing polyimide. Here, the fluorine-containing polyimide refers to a polyimide having a fluorine atom in the structure, and at least one of the acid anhydride and diamine of the polyimide raw material has a fluorine-containing group. The fluorine-containing polyimide is, for example, in the above general formula (1), where Ar ₁ is a tetravalent organic group, and Ar ₂ is a divalent organic group represented by the following general formula (2) or (3) Those represented by organic bases.

_{R 1} to R _{8 in the} above general formula (2) or general formula (3) independently represent a hydrogen atom, a fluorine atom, an alkyl or alkoxy group with a carbon number of 1 to 5, or a fluorine-substituted hydrocarbon group, the general formula (2) _{At least one of R 1} to R ₄ is a fluorine atom or a fluorine-substituted hydrocarbon group, and _{at least one of R 1} to R ₈ in the general formula (3) is a fluorine atom or a fluorine-substituted hydrocarbon group.

Among them, _{suitable specific examples of R 1} to R ₈ such as -H, -CH ₃ , -OCH ₃ , -F, -CF _3, etc., at least one substituent in formula (2) or formula (3) may be Either -F or -CF _3.

_{In addition, specific examples of Ar 1} in the general formula (1) when the fluorine-containing polyimide is formed are the following tetravalent acid anhydride residue.

In addition, when the fluorine-containing polyimide is formed, considering the transparency of the polyimide or the peelability from other layers, etc., the _{specific diamine residue of Ar 2 of the} general formula (1) is given, for example, the following Better.

In the case of the fluorine-containing polyimide, it is assumed that the interface with the polyimide having other structures other than the fluorine-containing polyimide can also have good separation properties (of course, the first and second polyimide layers When both are fluorine-containing polyimide, the separation of the interface can be further improved). Moreover, when the fluorine-containing polyimide has any one of the structural units represented by the following general formula (4) or (5) in the proportion of 80 mol% or more, due to the addition of transparency and peeling In addition to the properties, the thermal expansion is low and the dimensional stability is excellent, so it can be suitably used as the polyimide for forming the second polyimide layer.

Here, when the polyimide having the structure of the general formula (4) or (5) is used as the polyimide, in addition to the polyimide, other polyimides may be added in a proportion of less than 20 mol%. In the case of imine, there is no particular limitation, and general acid anhydrides and diamines can be used. Among them, the preferred anhydrides used include pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 1,4-cyclohexanedicarboxylic acid, 1,2,3 ,4-Cyclobutanetetracarboxylic dianhydride, 2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, etc. In addition, diamines such as 4,4'-diaminodiphenyl sulfide, trans-1,4-diaminocyclohexane, 4,4'-diaminocyclohexylmethane, 2,2'-bis (4-Aminocyclohexyl)-hexafluoropropane, 2,2'-bis(trifluoromethyl)-4,4'-diaminobicyclohexane, etc.

The various polyimides described above are obtained by the imidization of polyimides, but the resin solution of polyimides can be obtained by essentially using diamines and acids such as molar raw materials. The dianhydride is obtained by reacting in an organic solvent. More specifically, by dissolving the diamine in an organic polar solvent such as N,N-dimethylacetamide under nitrogen flow, adding tetracarboxylic dianhydride, and performing the reaction at room temperature for about 5 hours. be made of. In terms of uniformity of the film thickness during coating and the mechanical strength of the obtained polyimide film, the weight average molecular weight of the obtained polyimide film is preferably 10,000 to 300,000. Moreover, the preferred molecular weight range of the polyimide layer is the same molecular weight range as that of the polyamide acid.

In the present invention, by using polyimide having a structural unit represented by general formula (4) or (5) as the second polyimide layer 8, a thermal expansion coefficient of 25 ppm/K or less can be formed (preferably 10 ppm/K or less) polyimide layer is preferable, and it is suitable as a polyimide substrate for forming a display device. In addition, the polyimide with these structural units has a glass transition temperature (Tg) above 300°C, and the transmittance in the wavelength range of 440nm to 780nm is above 80%.

As mentioned above, with the specified polyimide, the interface between the first polyimide layer and the second polyimide layer can be easily separated from each other. Preferably, at least one polyimide layer is made of fluorine-containing Formed by polyimide. By making at least one polyimide layer made of fluorine-containing polyimide, the bonding strength of the interface between the first polyimide layer and the second polyimide layer is 1N/m or more and 500N/m The following is preferable, preferably 5 N/m or more and 300 N/m or less, and more preferably 10 N/m or more and 200 N/m or less, and has a separability that can be easily peeled off by hand. Secondly, since the separated display device will not be wrinkled or cracked in the second polyimide layer that becomes the polyimide substrate, the second polyimide layer can directly maintain the second polyimide layer. The surface roughness of the separating surface obtained by the casting method (generally, the surface roughness Ra=about 1~80nm) will not adversely affect the visibility of the display device.

The present invention includes 1) a method of separating the boundary surface between the first polyimide layer and the second polyimide layer after forming the designated display part, and 2) after forming the designated display part, first removing the first polyimide layer The support body on the side of the imine is separated, and the remaining boundary surface between the first polyimide layer and the second polyimide layer is separated to prepare the polyimide substrate (the second polyimide layer). ) The above is a method of a display device with a display unit. In the method of 2) above, after the support 1 is removed, the first polyimide layer 7 and the second polyimide layer 8 are separated, so that the second polyimide layer 8 and the display portion 4 are separated during separation. The shape is fixed in a certain way, and it is better to separate the first polyimide layer 7 at the same time. Thereby, the stress applied to the display portion 4 can be reduced, and even when the second polyimide layer 8 is thinner, the possibility of damage to the device of the display portion 4 can still be reduced. Here, there are no particular restrictions on the means for removing the support in the above 2) method, as long as it does not damage the display portion 4 or the second polyimide layer 8. The following methods can be used . In other words, the above description in Fig. 3 is an example using the adhesive layer 6, and this point is supplemented by the description of the coating method in Fig. 6. However, as long as the laminating method can be directly connected with the first polyimide layer 7 and the support 1 as long as it can be heated, pressed and melted, as shown in Figure 3, the adhesive layer 6 is not necessarily used. In this case, it can be combined with the following means Remove the support 1 in the same way.

Next, an application example of the coating method of the present invention will be explained.

<Coating Method>

FIG. 6 shows a state in which the first polyimide layer 7 and the second polyimide layer 8 are formed on the support 1 in order by a coating method, and then the display portion 4 is further laminated. In this method, the support 1 is first prepared, and the polyamide resin solution that becomes the first polyimide layer 7 is coated on it, and dried by heat treatment to complete the imidization to form the first polyimide layer. Polyimide layer 7. Then, the first polyimide layer 7 is coated with a polyimide resin solution that becomes the second polyimide layer 8, and it is dried by heat treatment to complete the imidization to form a second polyimide layer. Imine layer 8. In this way, a substrate in which the first polyimide layer 7 and the second polyimide layer 8 are sequentially formed on the support 1 can be formed. Next, continue to supply to the steps after the display portion forming step. Since the steps after the display portion forming step are the same as the above-mentioned layering method, detailed description is omitted, and the support 1 for removing the method of 2) above will be briefly described below.

As described above, FIG. 6 shows a state in which the first polyimide layer 7, the second polyimide layer 8, and the display portion 4 are sequentially laminated on the support 1. The present invention can also remove the support 1 before the step of separating the boundary surface of the first polyimide layer 7 and the second polyimide layer 8 from this state, but here the method of removing the support 1 is, for example, A polyimide material that is easily peeled from the support 1 is used as the first polyimide layer 7, and a metal foil such as copper foil or a metal substrate is used as the support 1, and these methods are removed with an etching solution.

In addition, the method of removing the support 1 may also be a conventional method. In other words, the support 1 may be removed by the laser irradiation of Non-Patent Document 3 or the release layer of Non-Patent Document 4. When the support 1 is removed by laser irradiation, the first polyimide layer can absorb the laser and can prevent the laser from adversely affecting the second polyimide layer or the display portion. When the support 1 is removed by the peeling layer, the first polyimide layer can react to the stress generated during peeling, and function as a stress buffer layer, and can prevent the display part damage caused by peeling and the problem of reduced handling properties .

Here, as disclosed in JP 2007-512568, by forming a yellow film such as polyimide on glass, and then forming thin-film electronic components on the yellow film, UV laser light irradiates the yellow film through the glass On the bottom surface, the glass and yellow film can be peeled off. In addition, it is also disclosed that when transparent plastics are different from yellow films, since they do not absorb UV laser light, an absorption/release layer such as amorphous silicon must be provided under the film in advance. In addition, Special Form No. 2012-511173 discloses that in order to peel off glass and polyimide film by irradiating UV laser light, a laser in the spectral range of 300~410nm must be used.

In the present invention, when laser light is used to remove the support from the first polyimide layer, it is preferable to use colored polyimide in the first polyimide layer. The first polyimide layer is colored polyimide and the second polyimide layer is transparent polyimide, which is one of the preferred forms of the present invention.

The coating method is to coat the polyimide resin solution that becomes the first polyimide layer 7 on the support 1 and heat it. At this time, heat treatment is performed sufficiently to make the first polyimide layer a Amination is preferred because the second polyimide layer can be easily separated. In addition, the coating method is also the same as described in the layering method, and at least one of the first or second polyimide layer is preferably a polyimide having a specific chemical structure. The first polyimide layer and the second polyimide layer can also be polyimide with the same chemical structure.

The coating method is to coat the resin solution on the first polyimide layer and the second polyimide layer at the same time, and then dry by heat treatment or drying. It is hardened, but in the present invention, the heating time (hereinafter referred to as high temperature) in the above heat treatment is from a temperature 20℃ lower than the maximum heating temperature (maximum reaching temperature) at the time of heating up to the high temperature heating temperature range of the maximum reaching temperature Keeping time), the shorter one is within the range of available necessary characteristics. Moreover, in the coating method, the purpose of maintaining the first and/or second polyimide layer in the high-temperature heating temperature range is to completely remove the residual solvent and promote the alignment of the polyimide resin to obtain the original The properties required for the polyimide layer. In addition, especially when the high-temperature holding time of the second polyimide layer is long, the peelability from the first polyimide layer is reduced, and the transmittance tends to decrease due to coloring. The most suitable high-temperature holding time depends on the heating method, the thickness of the polyimide, and the type of polyimide. It is better than 0.5 minutes and less than 60 minutes, and more than 0.5 minutes and less than 30 minutes. good.

Next, an application example of the combined use of film lamination and resin solution coating of the present invention will be explained.

<and usage>

Figure 8 shows that the first polyimide layer 7 cut into a smaller area than the support 1 is attached to the support 1 by the adhesive 6, and then the second polyimide layer is laminated on it. The state of the layer 8 and the display part 4.

In this method, the support 1 is first prepared, and then the polyimide film that becomes the first polyimide layer 7 is attached to it by the adhesive 6. Here, the same polyimide film as the above-mentioned lamination method can be used and the same method can be used.

Next, apply a resin solution of polyamide acid to become the second polyimide layer 8 on the first polyimide layer 7, and dry by heat treatment to complete the imidization to form a second polyimide layer. Imine layer 8. Here, the same resin solution as the above-mentioned coating method can be used and the same method can be used. In this way, a substrate in which the first polyimide layer 7 and the second polyimide layer 8 are sequentially formed on the support 1 can be formed. Then, it is provided to the steps after the display portion forming step. Since the steps after the display portion forming step are the same as the above, the description is omitted.

And the usage system is to apply the polyimide resin solution that will become the second polyimide layer 8 in a varnish state and cover the entire surface after the first polyimide layer 7 and the support 1 are laminated. On the first polyimide layer 7. The coated polyimide resin solution is dried and imidized by heat treatment to form a second polyimide layer 8, as shown in Figure 8 in this state, the second polyimide The lamination surface of the layer 8 is larger than that of the first polyimide layer, and at least part of the part that is not connected to the first polyimide layer 7 of the second polyimide layer 8 is connected to the support 1. In other words, a part of the second polyimide layer 8 extends more outwardly than the peripheral portion of the first polyimide layer, and the outwardly extending portion of the second polyimide layer 8 is fixed to the support body 1 on. In this method, the second polyimide layer 8 and the first polyimide layer 7 are easily peeled off. However, the second polyimide layer 8 and the support 1 can be formed by the second polyimide layer. The outward extending portion of the imine layer 8 is firmly bonded, so that the stability of the periphery of the support in the step of improving the adhesion can be more ensured. Moreover, after the display portion is formed, it is sufficient to perform the same step as the above-mentioned cutting step. As shown in FIG. 9, the display portion 4 and the second polyimide are cut along the cutting line 5 of the cut display portion 4. Layer 8, and separating the boundary surface between the first polyimide layer 7 and the second polyimide layer 8, and the resulting polyimide substrate formed by the second polyimide layer 8 is equipped with The display device of the display part 4.

In the present invention, the three methods mentioned above and the methods other than these are included. Since the first polyimide layer is subsequently separated, the function of the display device will not be imparted, but the display part is considered When the temperature changes during the manufacturing step, the characteristic until separation is an important factor. From this point of view, the thermal expansion coefficient of the first polyimide layer is preferably 25 ppm/K or less. In addition, the glass transition temperature Tg is preferably 300°C or higher. Specific examples of the first polyimide layer include polyimide having a structural unit composed of biphenyltetracarboxylic dianhydride and phenylenediamine as main components. Commercially available products, for example, UPILEX-S manufactured by Ube Kosan Co., Ltd., KAPTON manufactured by DuPont-TORAY Co., Ltd., and XENOMAX manufactured by Toyobo Co., Ltd. can be used.

In addition, in the present invention, when the display portion is formed, it can also be formed with an inorganic oxide film such as silicon oxide, aluminum oxide, silicon carbide, silicon carbon oxide, silicon nitride carbide, silicon nitride, silicon oxynitride, etc. A gas barrier layer for oxygen or water vapor. At this time, in order to reduce the warpage of the obtained display device, the difference between the thermal expansion coefficient of the second polyimide layer and the gas barrier layer is preferably 10 ppm/K or less.

In addition to using a polyimide with a specific chemical structure for the first or second polyimide layer, the first polyimide layer 7 and the second polyimide layer 7 can be easily separated from the second polyimide layer. In the case of the imide layer 8, for example, heat treatment of the first polyimide layer 7 is used, and after the surface state of the first polyimide layer 7 is changed to reduce the surface wettability, the second polyimide layer is coated quickly. A method of laminating a thin film of the imide layer 8. The appropriate temperature during the heat treatment depends on the type of the first polyimide layer 7. The first polyimide layer 7 is KAPTON manufactured by DuPont-TORAY Co., Ltd., and UPILEX-S manufactured by Ube Industries Co., Ltd. In the case of a polyimide film, it is preferably 300°C or more and 500°C or less.

In the present invention, the method of separating the boundary surface between the first polyimide layer and the second polyimide layer after the designated display portion is formed can also be supported by the separated second polyimide layer. On the side of the first polyimide layer of the laminated body of the first polyimide layer, the second polyimide layer is formed again, and the laminated body of the support and the first polyimide layer is used. For repeated use, after separating the second polyimide layer, the laminate of the support and the first polyimide layer may be washed. In addition, it is also possible to heat the laminate of the support and the first polyimide layer to reduce the wettability of the surface of the first polyimide layer, and then to coat the second polyimide layer.

In addition, other methods of repeatedly using the laminate of the support and the first polyimide layer can also be used in the first of the laminate of the support of the second polyimide layer and the first polyimide layer. On the side of the polyimide layer, the first polyimide layer is formed again, and then the second polyimide layer is formed.

Furthermore, the support removed from the first polyimide layer can also be used again in the present invention. The support can also be washed, heat treated, and surface treated before reuse.

[Example]

In the following, the present invention will be explained more specifically based on examples. Furthermore, the present invention is not limited by the contents of the following embodiments.

In the following examples, methods for evaluating physical properties and the like are shown.

[Transmittance (%)]

The polyimide film (50mm×50mm) was used to obtain the average value of the light transmittance from 440nm to 780nm with a U4000 spectrophotometer.

[Glass transition temperature (Tg)]

The glass transition temperature is using a viscoelastic analyzer (RSA-II manufactured by Rheometric Scientific Co., Ltd.), using a sample with a width of 10mm, applying 1Hz vibration, and at the same time heating from room temperature to 400°C at a rate of 10°C/min When it is calculated from the maximum value of the loss tangent (Tanδ).

[Coefficient of Thermal Expansion (CTE)]

Make a polyimide film with a size of 3mm×15mm in a thermomechanical analysis (TMA) device with a load of 5.0g and at the same time at a certain heating rate (20℃/min), within the temperature range from 30℃ to 260℃ A tensile test was performed, and the coefficient of thermal expansion (×10 ^-6 /K) was measured from the tensile amount of the polyimide film with respect to the temperature.

(Example 1)

After curing, the thickness is 20μm, and the coating area is 300mm×380mm. The combination of PDA (1,4-phenylenediamine) and BPDA (3,3',4,4'-biphenyltetracarboxylic dianhydride) The obtained polyamide resin solution was coated on the glass substrate of the support, and heated and dried at 130° C. to remove the solvent (DMAc: N,N-dimethylacetamide) in the resin solution. Then, heat treatment is performed from 160°C to 360°C at a heating rate of about 1°C/min to be imidized to form a first polyimide layer with a thickness of 20μm (surface roughness Ra=1.3nm, Tg =355°C).

The coating area of the first polyimide layer is larger than that of the first polyimide layer and covers the entire first polyimide layer. The coating area is 310mm×390mm and the cured thickness is 25μm. Formic acid dianhydride), 6FDA (2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride) and TFMB (2,2'-bis(trifluoromethyl)-4,4'- The polyamide resin solution obtained by diaminobiphenyl) was coated on the first polyimide layer, and heated and dried at 130°C to remove the solvent (DMAc: N,N-dimethyl) in the resin solution. Vinyl amine). Then, heat treatment is performed from 160° C. to 360° C. at a heating rate of about 20° C./min to be imidized, and a second polyimide layer with a thickness of 25 μm is formed. The high temperature holding time at this time is 1 minute. Moreover, when synthesizing the above polyamide acid, the diamine component and the acid dianhydride component are approximately equal moles, and the ratio of PMDA/6FDA is 85/15.

Thus formed a laminate in which the first and second polyimide layers are sequentially laminated on the glass, and formed on the second polyimide layer side of the laminate is an EL element having a display portion. Then, in a manner to enclose the entire display portion, a score is placed on the second polyimide layer, and the interface between the first polyimide layer and the second polyimide layer is peeled and separated, and the second polyimide layer is prepared. The polyimide substrate formed by the dimerimide layer is a display device with EL elements. At this time, between the first polyimide layer and the second polyimide layer, there is no damage to the display part of the TFT, electrode, etc., and no means such as laser peeling are used. It can be peeled off manually and easily separated. The peel strength of the first polyimide layer and the second polyimide layer is 3.5 N/m. Moreover, in the above embodiment, the linear expansion coefficient of the first polyimide layer is 12.0 ppm/K, and the linear expansion coefficient of the second polyimide layer is 9.7 ppm/K. In addition, the transmittance of the second polyimide layer in the wavelength range of 440 nm to 780 nm is 83.5%.

(Example 2)

After curing, the thickness is 20μm and the coating area of 310mm×390mm will be combined with PDA (1,4-phenylenediamine) and BPDA (3,3',4,4'-biphenyltetracarboxylic dianhydride) The obtained polyamide resin solution was coated on the glass substrate of the support, and heated and dried at 120° C. to remove the solvent (DMAc: N,N-dimethylacetamide) in the resin solution. Then, heat treatment from 130°C to 360°C at a heating rate of about 1°C/min to form a first polyimide layer with a thickness of 25μm (surface roughness Ra=1.3nm, Tg =355°C).

With a coating area of 310mm×390mm and a thickness of 5μm after curing, PMDA (pyromellitic dianhydride), 6FDA (2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane) A resin solution of polyamide acid obtained by dianhydride) and TFMB (2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl) is coated on the first polyimide layer And heat and dry at 130°C to remove the solvent (DMAc: N,N-dimethylacetamide) in the resin solution. Then, heat treatment is performed from 160° C. to 360° C. at a heating rate of about 20° C./min to be imidized to form a second polyimide layer with a thickness of 5 μm. Moreover, when synthesizing the above polyamide acid, the diamine component and the acid dianhydride component are approximately equal moles, and the ratio of PMDA/6FDA is 60/40.

Thus formed a laminate in which the first and second polyimide layers are sequentially laminated on the glass, and formed on the second polyimide layer side of the laminate is an EL element having a display portion. Then, in a manner to enclose the entire display portion, nicks are placed in the thickness direction of the first polyimide layer and the second polyimide layer, and the glass on the side of the first polyimide layer is peeled and removed, and then The interface between the first polyimide layer and the second polyimide layer is peeled off, and the polyimide substrate formed by the second polyimide layer is prepared with a display device with EL elements on the polyimide substrate. At this time, between the glass and the first polyimide layer, and by means of no damage to the display part of the TFT, electrode, etc., and no means such as laser peeling, it can be peeled off manually. Easy to separate. The peel strength of the first polyimide layer and the second polyimide layer is 4.0 N/m. Moreover, in the above embodiment, the linear expansion coefficient of the first polyimide layer is 7.0 ppm/K, and the linear expansion coefficient of the second polyimide layer is 20.4 ppm/K. In addition, the transmittance of the second polyimide layer in the wavelength range of 440 nm to 780 nm is 86.7%.

(Example 3)

In order to reuse the laminated body of the support and the first polyimide layer that have been peeled and separated from the second polyimide layer in Example 1, after removing the peripheral portion of the remaining second polyimide layer, Rinse with pure water, then heat treatment at 100℃, 200, 300℃, and 360℃ for 2 minutes.

Coat the first polyimide layer with the same polyimide resin solution as the second polyimide layer of Example 1, and heat and dry it at 130°C, and then from 160°C to 360°C The temperature was increased at a rate of about 20°C/min, and the temperature was maintained at 360°C for 60 minutes to form a second polyimide layer with a thickness of 25 μm. The high temperature retention time at this time was 61 minutes.

Thus, a laminate in which the first polyimide layer and the second polyimide layer were sequentially laminated on the glass was formed, and the display device was manufactured in the same order as in Example 1. In addition, the peel strength of the first polyimide layer and the second polyimide layer is 10.0 N/m, which can be easily separated by hand. Moreover, the linear expansion coefficient of the second polyimide layer is 9.3 ppm/K, and the transmittance of the second polyimide layer in the wavelength range of 440 nm to 780 nm is 78.5%.

(Example 4)

After curing, the thickness is 25μm and the coating area is 310mm×390mm. The m-TB (2,2'-dimethylbenzidine) 17.70g, TPE-R (1,3-bis(4-amine) Phenoxy) benzene 4.3g and PMDA (pyromellitic dianhydride) 17.20g and BPDA (3,3',4,4'-biphenyltetracarboxylic dianhydride) 5.8g obtained polyamide acid The resin solution was coated on the glass substrate of the support, and heated and dried at 120°C to remove the solvent (DMAc: N,N-dimethylacetamide) in the resin solution. Then, by heating from 130°C to 160°C to remove the solvent in the resin solution. Heat treatment at a heating rate of about 15°C/min to ℃ to form a first polyimide layer with a thickness of 25μm (surface roughness Ra=1.0nm, Tg=360°C).

Coat the first polyimide layer with the same polyimide resin solution as the second polyimide layer of Example 1 with a coating area of 306mm×386mm, and at 130°C After heating and drying, the temperature is increased from 160°C to 360°C at a rate of about 20°C/min, and the temperature is maintained at 360°C for 30 minutes to form a second polyimide layer with a thickness of 25 μm. The high temperature retention time at this time is 31 minutes.

Thus, a laminate in which the first polyimide layer and the second polyimide layer were sequentially laminated on the glass was formed, and the display device was manufactured in the same order as in Example 2. In addition, the peel strength of the first polyimide layer and the second polyimide layer is 110 N/m, which can be separated by hand. Furthermore, the linear expansion coefficient of the first polyimide layer was 20.0 ppm/K, and the linear expansion coefficient of the second polyimide layer was 9.5 ppm/K. In addition, the transmittance of the second polyimide layer in the wavelength range of 440 nm to 780 nm is 80.5%.

(Example 5)

After curing, the thickness of the polyamide acid resin obtained from PDA (1,4-phenylenediamine) and BPDA (3,3',4,4'-biphenyltetracarboxylic dianhydride) The solution was coated on the copper foil, and heated and dried at 130°C to remove the solvent (DMAc: N,N-dimethylacetamide) in the resin solution. Then, heat treatment is performed from 160°C to 360°C at a heating rate of about 1°C/min to be imidized to form a first polyimide layer with a thickness of 20μm (surface roughness Ra=1.3nm, Tg =355℃) on copper foil.

In a way that the cured thickness is 25μm, PMDA (pyromellitic dianhydride), 6FDA (2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride) and TFMB (2, 2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl) resin solution of polyamide acid was coated on the first polyimide layer and heated at 130°C Dry and remove the solvent (DMAc: N,N-dimethylacetamide) in the resin solution. Then, heat treatment is performed from 160° C. to 360° C. at a heating rate of about 20° C./min to be imidized, and a second polyimide layer with a thickness of 25 μm is formed. Moreover, when synthesizing the above polyamide acid, the diamine component and the acid dianhydride component are approximately equal moles, and the ratio of PMDA/6FDA is 85/15.

The copper foil part of the laminate formed by the copper foil/first polyimide layer/second polyimide layer was removed by etching with ferric chloride, and the first polyimide layer/second polyimide layer was prepared. Laminated film made of dimer imide layer.

The laminated film was adhered to the glass substrate of the support with an epoxy resin adhesive, and then the EL element of the display portion was formed on the side of the second polyimide layer. Then, the interface between the first polyimide layer and the second polyimide layer is separated by peeling, and a display device with an EL element on the polyimide substrate is prepared. The first polyimide layer and the second polyimide layer can be easily separated without damaging devices such as TFTs and electrodes in the display portion. Moreover, in the above embodiment, the linear expansion coefficient of the first polyimide layer is 12.0 ppm/K, and the linear expansion coefficient of the second polyimide layer is 9.7 ppm/K. In addition, the transmittance of the second polyimide layer in the wavelength range of 440 nm to 780 nm is 83.5%.

1‧‧‧Glass substrate

4‧‧‧Display (TFT/Organic EL Panel)

6‧‧‧Next layer

7‧‧‧The first polyimide layer

8‧‧‧Second polyimide layer

Claims (15)

A method for manufacturing a display device, which is characterized by forming a first polyimide layer and a second polyimide layer on a support in a laminated manner, and then further forming on the second polyimide layer Then cut the display part and the second polyimide layer along the cutting line to cut the display part, and separate the boundary surface of the first polyimide layer and the second polyimide layer to make On the polyimide substrate formed by the second polyimide layer is a display device equipped with a display portion, the first polyimide layer or the second polyimide layer has the following general formula ( 1) It is made of polyimide of the structural unit shown, so that part of the second polyimide layer extends outward from the periphery of the first polyimide layer, and the second polyimide layer The outwardly extending part is fixed and then attached to the support body,

(In the formula, Ar ₁ is any one or more of tetravalent organic groups selected from the acid anhydride residues of the following formulae, Ar ₂ is a divalent organic group of diamine residues, and at least one of _{Ar 1} and Ar _{2 is aromatic} Family residues)

The method for manufacturing a display device according to claim 1, wherein the acid anhydride as the raw material of the polyimide having the structural unit represented by the general formula (1) is selected from 3,3',4,4'-biphenyl tetrakis One or more acid anhydrides of the group of carboxylic dianhydride and pyromellitic dianhydride. The method for manufacturing a display device according to claim 1, wherein the diamine as the raw material of the polyimide having the structural unit represented by the above general formula (1) is selected from 1,4-phenylenediamine, 2,2' -One or more diamines of the group consisting of dimethylbenzidine and 1,3-bis(4-aminophenoxy)benzene. The method for manufacturing a display device according to claim 1, wherein the peel strength of the first polyimide layer and the second polyimide layer is 1 N/m or more and 500 N/m or less. The method for manufacturing a display device according to claim 1, wherein the peel strength of the first polyimide layer and the second polyimide layer is 5 N/m or more and 300 N/m or less. The method for manufacturing a display device according to claim 1, wherein the peel strength of the first polyimide layer and the second polyimide layer is 10 N/m or more and 200 N/m or less. The method for manufacturing a display device according to claim 1, wherein the first polyimide layer is a polyimide having a structural unit represented by the above general formula (1), and the second polyimide layer is a fluorine-containing polyimide Imine. A method for manufacturing a display device, which is characterized by forming a first polyimide layer and a second polyimide layer on a support in a laminated manner, and then further forming on the second polyimide layer Specify the display area, and then separate the boundary surface between the first polyimide layer and the second polyimide layer, and the polyimide substrate made of the second polyimide layer is made of In the display device of the section, the first polyimide layer or the second polyimide layer is made of polyimide having a structural unit represented by the following general formula (1),

(In the formula, Ar ₁ is any one or more of tetravalent organic groups selected from the acid anhydride residues of the following formulae, Ar ₂ is a divalent organic group of diamine residues, and at least one of _{Ar 1} and Ar _{2 is aromatic} Family residues)

The method for manufacturing a display device according to claim 8, wherein the acid anhydride as the raw material of the polyimide having the structural unit represented by the general formula (1) is selected from 3,3',4,4'-biphenyl tetrakis One or more acid anhydrides of the group of carboxylic dianhydride and pyromellitic dianhydride. Such as the manufacturing method of the display device of claim 8, wherein as a tool The diamine of the polyimide having the structural unit represented by the above general formula (1) is selected from 1,4-phenylenediamine, 2,2'-dimethylbenzidine and 1,3-bis( One or more diamines of the group of 4-aminophenoxy)benzene. The method for manufacturing a display device according to claim 8, wherein the peel strength of the first polyimide layer and the second polyimide layer is 1 N/m or more and 500 N/m or less. The method for manufacturing a display device according to claim 8, wherein the peel strength of the first polyimide layer and the second polyimide layer is 5 N/m or more and 300 N/m or less. The method for manufacturing a display device according to claim 8, wherein the peel strength of the first polyimide layer and the second polyimide layer is 10 N/m or more and 200 N/m or less. The method for manufacturing a display device according to claim 8, wherein the first polyimide layer is a polyimide having a structural unit represented by the above general formula (1), and the second polyimide layer is a fluorine-containing polyimide Imine. A method of manufacturing a display device, which is formed on a laminate of a support that has been peeled off from the second polyimide layer and the first polyimide layer by the manufacturing method of claim 1 or 8. After the second polyimide layer, a designated display portion is further formed on the second polyimide layer, and then the boundary surface between the first polyimide layer and the second polyimide layer is separated to obtain On the polyimide substrate formed by the second polyimide layer is a display device equipped with a display portion.

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