JPWO2014050933A1 - Manufacturing method of display device - Google Patents

Abstract

In the present invention, after a predetermined display portion is formed on a resin base material integrated with a support in advance, the resin base material can be easily separated from the support, and a display device can be easily obtained. It is an object to provide a method for manufacturing a display device. In the present invention, the predetermined display portion (4) is formed on the second resin layer in a state where the first resin layer (7) and the second resin layer (8) are laminated on the support (1). Then, separation at the boundary surface between the first resin layer and the second resin layer to obtain a display device having a display unit on a resin base material composed of the second resin layer. Is the method.

Description

  The present invention relates to a method for manufacturing a display device, and more particularly to a method for manufacturing a display device in which a display portion in a liquid crystal display device, an organic EL display device, or the like is formed on a resin substrate.

  Display devices such as liquid crystal display devices and organic EL display devices are used for various display applications such as large displays such as televisions and small displays such as mobile phones, personal computers, and smartphones. As a typical display device, there is an organic EL display device. For example, in this organic EL display device, a thin film transistor (hereinafter referred to as TFT) is formed on a glass substrate which is a supporting base, and an electrode, a light emitting layer, and an electrode Are sequentially formed and finally hermetically sealed with a glass substrate or a multilayer thin film.

  Here, by replacing the glass substrate, which is a supporting base material, with a resin base material from a conventional glass substrate, it is possible to realize thinness, light weight, and flexibility, and further expand the application of the display device. However, since resins are generally inferior in dimensional stability, transparency, heat resistance, moisture resistance, gas barrier properties and the like as compared with glass, they are currently in the research stage and various studies have been made.

  For example, Patent Document 1 relates to a polyimide useful as a plastic substrate for a flexible display and an invention relating to a precursor thereof, using tetracarboxylic acids containing an alicyclic structure such as cyclohexylphenyltetracarboxylic acid. It has been reported that polyimides reacted with various diamines are excellent in transparency. In addition to this, attempts have been made to reduce the weight by using a flexible resin for the support substrate. For example, in the following Non-Patent Documents 1 and 2, an organic material in which highly transparent polyimide is applied to the support substrate. An EL display device has been proposed.

  Thus, it is known that resin films such as polyimide are useful for plastic substrates for flexible displays, but the manufacturing process of display devices has already been performed using glass substrates, and most of the production facilities Is designed on the assumption that a glass substrate is used. Therefore, it is desirable to be able to produce display devices while effectively utilizing existing production equipment.

  As one specific example of the study, a predetermined display device manufacturing process is completed in a state where a resin film is laminated on a glass substrate, and then the glass substrate is removed to provide a display unit on the resin base material. A display device manufacturing method is known (see Patent Document 2, Non-Patent Document 3, and Non-Patent Document 4). In these cases, it is necessary to separate the resin substrate and the glass without damaging the display unit (display unit) formed on the resin substrate.

  That is, in Non-Patent Document 3, after a predetermined display portion is formed on a resin base material applied and fixed on a glass substrate, a laser is applied from the glass side by a method called an EPLaR (Electronics on Plastic by Laser Release) process. To forcibly separate the resin substrate provided with the display portion from the glass. However, this method not only requires an expensive laser device, but also has a disadvantage of low productivity because it takes time for separation. In addition, during separation, the surface properties of the resin substrate and the display unit mounted thereon may be adversely affected.

  On the other hand, the method described in Non-Patent Document 4 is a method in which the defects of the EPLaR method are improved, and after forming a release layer on a glass substrate, a polyimide resin is applied on the release layer to display an organic EL display. In this method, the polyimide film layer is peeled from the release layer after the manufacturing process of the device is completed. Here, FIGS. 1 and 2 show a method for manufacturing an organic EL display device described in Non-Patent Document 4. FIG. In this method, after the release layer 2 is formed on the glass substrate 1, the polyimide layer 3 is formed to be slightly larger than the release layer 2, and thereafter, the predetermined TFT and organic EL process processes are performed. After forming the panel portion (display portion) 4, the polyimide layer 3 and the TFT / organic EL panel portion (display portion) 4 are separated from the release layer 2 along the cutting line 5 inside the release layer 2. 2 is peeled off. However, Non-Patent Document 4 has no specific description such as what to use for the release layer. For this reason, it is unclear how much force is actually required for separation from the release layer and what state the surface properties of the separated polyimide layer 3 will be. Moreover, since it is necessary to make the area of a peeling layer smaller than the area of a polyimide layer, the area which can form an organic EL display device has a restriction | limiting, and there exists a subject in productivity. Increasing the area of the release layer to prevent a decrease in productivity reduces the area of the polyimide layer that adheres to the glass at the outer periphery of the release layer, and is prone to exfoliation due to stress during the process There is.

  Further, in the method described in Patent Document 2, after a release layer made of parylene or a cyclic olefin copolymer is formed on a glass substrate, a polyimide layer is made slightly larger than the release layer in the same manner as in Non-Patent Document 4. This is a method in which the polyimide layer is peeled off after forming and forming an electronic device thereon. In order to form TFTs required for display applications, an annealing process that generally reaches about 400 ° C. is necessary. However, in this method, the heat resistance of the release layer is inferior to that of polyimide. There exists a subject that the maximum temperature at the time of preparation is restrict | limited to the heat resistance of a peeling layer. Further, since the adhesion between the glass and the release layer and between the release layer and the polyimide layer is weak, it cannot withstand the stress during the process and may cause peeling. Furthermore, the thermal expansion coefficient of the release layer is larger than that of polyimide, and the difference in thermal expansion coefficient due to the difference in resin type can be a factor of warpage.

  Patent Document 3 describes a method for manufacturing a semiconductor device in which a semiconductor element is formed on a support substrate via a release layer and then a semiconductor element is formed, and then the support substrate is released from the resin film. . In Patent Document 3, polybenzoxazole is disclosed as a resin film. In general, polybenzoxazole is excellent in peelability from other materials as compared with polyimide. Here, in general, in order to ensure good peelability from other materials, the heat treatment time in contact with the adherend is preferably short, but in the case of polyimide benzoxazole, the heterocyclic ring and aromatic Since the ring has a coplanar structure, the crystallinity tends to be high, and a relatively long heat treatment time at high temperature is required to complete the reaction and sufficiently reduce the concentration of volatile components remaining in the film. . However, in Patent Document 3, it is unclear how much force is required for separation from the release layer, but it is disclosed that the release layer and the resin film can be peeled by being immersed in warm water. In addition, since the crystallinity is high, the film tends to be brittle. If an alicyclic structure, which is a flexible structure, is introduced to prevent this, there is a problem that heat resistance is lowered. Furthermore, the introduction of the alicyclic structure makes it difficult to reduce the thermal expansibility.

  These methods described in Patent Documents 2 to 3 and Non-Patent Documents 3 to 4 all use a glass as a support, and form a display portion on a resin base material fixed to the glass. In addition, there is an advantage that a glass substrate can be used as it is in a current production line for producing a display device such as a liquid crystal display device or an organic EL display device. Therefore, if it can be separated very easily after forming a predetermined display portion, and can be made not to affect the resin base material and the display portion, it can be a method with excellent mass productivity, The replacement from the glass substrate to the resin base material can be further promoted.

JP 2008-231327 A JP 2010-67957 A JP 2009-21322

S. An et. al., "2.8-inch WQVGA Flexible AMOLED Using High Performance Low Temperature Polysilicon TFT on Plastic Substrates", SID2010 DIGEST, p706 (2010) Oishi et. al., "Transparent PI for flexible display", IDW "11 FLX2 / FMC4-1 E.I. Haskal et. Al. "Flexible OLED Displays Made with the EPLaR Process", Proc. Eurodisplay "07, pp. 36-39 (2007) Cheng-Chung Lee et. Al. "A Novel Approach to Make Flexible Active Matrix Displays", SID10 Digest, pp.810-813 (2010)

  Accordingly, an object of the present invention is to easily separate the resin base material from the support body after forming a predetermined display portion on the resin base material previously integrated with the support body, thereby simplifying the display device. It is to provide a method that can be obtained.

As a result of studies conducted by the present inventors to solve the above problems, a predetermined display portion is formed on the second resin layer in a state where the first resin layer and the second resin layer are laminated on the support. Then, by separating at the interface between the first resin layer and the second resin layer, it was found that a display device provided with a display unit on the resin base material composed of the second resin layer can be obtained very simply, The present invention has been completed.
That is, the gist of the present invention is as follows.

［式中、Ａｒ₁は芳香環を有する４価の有機基を表し、Ａｒ₂は下記一般式（２）又は（３）で表される２価の有機基である。

〔ここで、一般式（２）又は一般式（３）におけるＲ₁〜Ｒ₈は、互いに独立に水素原子、フッ素原子、炭素数１〜５までのアルキル基若しくはアルコキシ基、又はフッ素置換炭化水素基であり、一般式（２）にあってはＲ₁〜Ｒ₄のうち、また、一般式（３）にあってはＲ₁〜Ｒ₈のうち、それぞれ少なくとも一つはフッ素原子又はフッ素置換炭化水素基である。〕］(1) In a state where the first resin layer and the second resin layer are laminated on the support, a predetermined display portion is formed on the second resin layer, and then the first resin layer and the second resin layer A display device manufacturing method comprising: obtaining a display device having a display unit on a resin base material made of a second resin layer by separating at a boundary surface.
(2) The laminated film in which the first resin layer and the second resin layer are directly laminated and the support are bonded to each other through the adhesive layer between the first resin layer surface of the laminated film and the one surface of the support. Later, a predetermined display portion was formed on the laminated film, and then separated at the boundary surface between the first resin layer and the second resin layer, and the display portion was provided on the resin base material composed of the second resin layer. A display device manufacturing method according to (1), characterized in that a display device is obtained.
(3) The manufacturing method of the display device according to (2), wherein each of the first resin layer and the second resin layer constituting the laminated film is made of polyimide.
(4) After the first polyimide layer and the second polyimide layer are formed on the support, a predetermined display portion is further formed, and then separated at the boundary surface between the first polyimide layer and the second polyimide layer, A method for producing a display device according to (1), characterized in that a display device having a display unit on a polyimide base material comprising a second polyimide layer is obtained.
(5) After forming a predetermined display part, after removing a support body, it isolate | separated in the interface of a 1st polyimide layer and a 2nd polyimide layer, and the display apparatus provided with the display part on the polyimide base material (4) The manufacturing method of the display apparatus as described in (4).
(6) The display device according to (4) or (5), wherein the first polyimide layer is formed by laminating a polyimide film and the second polyimide layer is formed by applying a resin solution of polyimide or a polyimide precursor. Production method.
(7) The method for producing a display device according to (4) or (5), wherein the first polyimide layer and the second polyimide layer are formed by applying and heating a resin solution of polyimide or a polyimide precursor.
(8) A part of the second polyimide layer protrudes from the peripheral edge of the first polyimide layer, and the protruding part of the second polyimide layer is fixed to the support. (4) to (7 ). A method for manufacturing a display device according to any one of the above.
(9) The display device according to any one of (4) to (7), wherein a part of one of the first polyimide layer and the second polyimide layer protrudes from the peripheral edge of the other layer. Manufacturing method.
(10) The display according to any one of (4) to (9), wherein the first resin layer and the second resin layer are separated after cutting the first resin layer along the outer periphery of the display unit. Device manufacturing method.
(11) When the second polyimide layer is formed by applying a polyimide or polyimide precursor resin solution and then heating, the high temperature holding time of the second polyimide layer is less than 60 minutes, (6) or ( 7) A method for producing a display device according to 7).
(12) The method for manufacturing a display device according to 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 first resin layer has a thermal expansion coefficient of 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 second resin layer has a transmittance in a wavelength region of 440 nm to 780 nm of 80% or more.
(16) The display according to any one of (1) to (15), wherein the display unit is formed through a gas barrier layer, and a difference in thermal expansion coefficient between the second resin layer and the gas barrier layer is 10 ppm / K or less. Device manufacturing method.
(17) The method for manufacturing a display device according to any one of (1) to (16), wherein the display unit 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 between the first resin layer and the second resin layer is 200 N / m or less.
(19) The display according to any one of (1) to (18), wherein at least one of the first resin layer or the second resin layer is made of polyimide having a structural unit represented by the following general formula (1). Device manufacturing method.

[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).

[Wherein, R _{1 to} R ₈ in the general formula (2) or the general formula (3) are each independently a hydrogen atom, a fluorine atom, an alkyl group or an alkoxy group having 1 to 5 carbon atoms, or a fluorine-substituted hydrocarbon. In the general formula (2), at least one of R _{1 to} R ₄ and R _{1 to} R _{8 in} the general formula (3) is a fluorine atom or a fluorine-substituted group. It is a hydrocarbon group. ]]

  According to the present invention, by forming the first resin layer and the second resin layer on the support, the predetermined display portion can be formed while ensuring handling and dimensional stability. Can do. After the display portion is formed, the display device can be obtained very easily because it can be easily separated using the interface between the first resin layer and the second resin layer without requiring laser irradiation or the like. Can do. In addition, the support is reused in the manufacture of the display device because there is no influence on the second resin layer and the display portion which become the resin base material after separation, and the support is not damaged. It is also possible to make a significant contribution to manufacturing cost reduction.

FIG. 1 is a schematic diagram for explaining a method of manufacturing an organic EL display device in the prior art. FIG. 2 is a schematic diagram for explaining a method of manufacturing an organic EL display device in the prior art. FIG. 3 is a schematic diagram for explaining a method for manufacturing a display device according to the present invention. FIG. 4 is a schematic diagram for explaining a method for manufacturing a display device according to the present invention. FIG. 5 is a schematic view (partially enlarged view) for explaining the method for manufacturing a display device according to the present invention. FIG. 6 is a schematic diagram for explaining a method for manufacturing a display device according to the present invention. FIG. 7 is a schematic diagram for explaining a method for manufacturing a display device according to the present invention. FIG. 8 is a schematic diagram for explaining a method for manufacturing a display device according to the present invention. FIG. 9 is a schematic diagram for explaining a method for manufacturing a display device according to the present invention.

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

  In the method for manufacturing a display device according to the present invention, a predetermined display portion is formed 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 the first resin is formed. A display device having a display portion on a resin substrate made of the second resin layer is obtained by separating at the boundary surface between the layer and the second resin layer. Details are as described below. In addition, below, as a suitable example, although the case where both a 1st resin layer and a 2nd resin layer are formed with a polyimide is demonstrated, at least one resin layer may be formed with resin other than a polyimide. Good.

  In the manufacturing method of the display device of the present invention, a substrate provided with a first polyimide layer and a second polyimide layer on a support in advance is used. And a predetermined display part is formed in the 2nd polyimide layer side, and after that, it isolate | separates in the interface of a 1st polyimide layer and a 2nd polyimide layer, The resin base material (polyimide base material) which consists of a 2nd polyimide layer It is possible to manufacture a display device having a display unit thereon.

  More specifically, first, as shown in FIG. 3, a support 1 serving as a pedestal in the manufacturing process of a display unit in a liquid crystal display device, an organic EL display device or the like is prepared. The support 1 is not particularly limited as long as it has chemical strength and mechanical strength that can withstand heat history, atmosphere, and the like in the manufacturing process of the display unit forming various display devices. A substrate or a metal substrate is exemplified, but a glass substrate is preferably used. As the glass substrate, for example, those generally used in the production of organic EL display devices can be used. However, in the display device manufactured by the present invention, the support base material of the display unit is a polyimide base material composed of the second polyimide layer 8. In other words, the glass substrate here serves as a pedestal when forming the display part on the polyimide base material, and ensures the handling and dimensional stability of the polyimide base material in the manufacturing process of the display part. Even if it does, it will eventually be removed and will not constitute a display device. The support may be subjected to a surface treatment for controlling the peelability of the first polyimide layer 7 and the second polyimide layer 8.

  In the present invention, the first polyimide layer and the second polyimide layer are provided on the support 1, and as the method, 1) the first polyimide layer and the second polyimide layer are laminated in advance, A method of laminating and forming a laminated polyimide film on a support (lamination method), 2) forming a first polyimide layer and a second polyimide layer using polyimide or a polyimide precursor (hereinafter also referred to as “polyamic acid”). A method of applying a resin solution (application method), 3) A polyimide film is laminated on a support to form a first polyimide layer, and a second polyimide layer is formed of a polyimide or polyimide precursor resin solution Any method of performing by coating (combined method) may be used. Here, the support 1 and the first polyimide layer may be directly adhered and laminated, or may be laminated via an adhesive layer as shown in FIG.

  In the present invention, at least a part of any one of the first polyimide layer and the second polyimide layer may be formed so as to protrude from the peripheral portion of the other layer. By providing a thin part of the polyimide layer in the peripheral part outside the part where the display part is formed, the stress generated during the process can be dispersed, and the support and the polyimide layer can be peeled off during the process. Can be prevented. The overhanging distance is not particularly limited, but is preferably not less than the total thickness of the first polyimide layer and the second polyimide layer, and more preferably not less than 10 times the total thickness.

Hereinafter, the above three methods will be described individually.
<Lamination method>
FIG. 3 shows a state in which a polyimide laminated film is attached to the support 1 with an adhesive layer 6 and a display portion is further laminated. Here, the polyimide laminated film is composed of a first polyimide layer 7 and a second polyimide layer 8, and the first polyimide layer 7 and the second polyimide layer 8 have a structure in which direct stacking is performed in advance. In order to obtain such a polyimide laminated film, for example, a polyamic acid resin solution to be the second polyimide layer 8 is applied on the polyimide film to be the first polyimide layer 7, and then dried and imidized by heat treatment. A method (cast method). In addition, as the adhesive layer 6, in addition to a resin adhesive such as an epoxy resin or an acrylic resin, an adhesive film provided with an adhesive layer on both surfaces of a support film can be used. Further, although the adhesive layer 6 is used in FIG. 3, as shown in FIG. 7, the first polyimide layer 7 side may be directly adhered to the support 1 by means such as thermocompression bonding.

  Here, the thickness of the second polyimide layer 8 constituting the laminated film is preferably 3 μm or more and 50 μm or less. If the thickness of the second polyimide layer 8 is less than 3 μm, it will be difficult to ensure electrical insulation when the resin base material of the display device is formed and to prevent damage to the resin layer due to external factors. If it exceeds, the flexibility and transparency of the display device may decrease. On the other hand, the first polyimide layer 7 does not directly constitute a display device, and therefore it is preferable that the thickness is 10 μm or more in consideration of handling properties as a laminated film. The upper limit of the thickness is not particularly limited, but is preferably 100 μm or less in consideration of cost and the like.

  As described above, the polyimide laminated film is transferred to the subsequent process for forming the display portion in a state where the polyimide laminated film is laminated and integrated on the support 1 with or without the adhesive layer 6. Here, the process for forming the display portion refers to a process process of a predetermined TFT / organic EL process in the case of an organic EL display device, for example, and includes a TFT, an electrode, and a light emitting layer formed thereby. An organic EL element or the like corresponds to the display unit. Here, an organic EL that performs color display by combining a white light emitting organic EL with a color filter has also been proposed. This color filter is manufactured separately from the TFT / organic EL process, and is then bonded to the TFT / organic EL side. This color filter also corresponds to the display unit. In the case of a liquid crystal display device, it refers to a process process of a TFT process, and a TFT formed thereby, a drive circuit, and a color filter as necessary correspond to a display portion. That is, the process of forming the display unit includes various functional layers conventionally formed on a glass substrate including various display devices such as an electronic paper and a MEMS display in addition to an organic EL display device and a liquid crystal display device. In this case, it refers to a process of forming parts necessary for projecting a predetermined video (moving image or image), and the parts obtained thereby are collectively referred to as a display unit. Through the process, the display unit 4 is laminated and formed on the second polyimide layer 8 side integrated with the first polyimide layer 7. And if all the display part lamination | stacking processes are complete | finished, it will progress to the cutting process cut | disconnected to a predetermined size.

  Among these, FIG. 4 represents a cutting process. In the present invention, the cutting step is not essential, and is optionally performed depending on the device to be manufactured and the mode of the step. For example, in the manufacture of the organic EL display device, the cutting is completely performed up to the display unit (TFT / organic EL panel unit) 4 and the second polyimide layer 8 along the cutting line 5 shown in FIG. At this time, as shown in FIG. 5 showing an enlarged view of the cutting region 9 shown in FIG. 4, the first resin is formed along the outer periphery of the display unit while allowing the cutting line 10 to reach the vicinity of the center of the first polyimide layer 7. If the layer is cut, the second polyimide layer 8 can be reliably and easily separated from the interface with the first polyimide layer 7 without causing mechanical damage to the TFT / organic EL panel portion 4. .

  Here, in order for the second polyimide layer 8 to be easily separated from the interface with the first polyimide layer 7, the polyimide interface needs to be easily peeled off. Although the means is not specifically limited, it is mentioned that the polyimide which has a specific chemical structure is used for at least any one of a 1st or 2nd polyimide layer.

式中、Ａｒ₁は酸無水物残基である４価の有機基を表し、Ａｒ₂はジアミン残基である２価の有機基であるが、耐熱性の観点から、Ａｒ₁、Ａｒ₂の少なくとも一方は、芳香族残基であることが好ましい。Generally, a polyimide is usually obtained by polymerizing an acid anhydride and a diamine which are raw materials, and is represented by the following general formula (1).

In the formula, Ar ₁ represents a tetravalent organic group that is an acid anhydride residue, and Ar ₂ is a divalent organic group that is a diamine residue. From the viewpoint of heat resistance, Ar ₁ and Ar ₂ At least one is preferably an aromatic residue.

特に好ましくは、下記繰り返し構造単位を有するポリイミドである。

Examples of the polyimide resin suitably used for the first polyimide layer or the second polyimide layer in the present invention include polyimides having the following repeating structural units,

Particularly preferred is a polyimide having the following repeating structural unit.

In addition to these, fluorine-containing polyimide may be used. Here, the fluorine-containing polyimide means one having a fluorine atom in the polyimide structure, and has a fluorine-containing group in at least one component of an acid anhydride and a diamine which are polyimide raw materials. As such a fluorine-containing polyimide, for example, among those represented by the general formula (1), Ar _{1 in} the formula is a tetravalent organic group, and Ar ₂ is represented by the following general formula (2) or (3 ) Represented by a divalent organic group represented by:

R _{1 to} R ₈ in the general formula (2) or the general formula (3) are each independently a hydrogen atom, a fluorine atom, an alkyl group or an alkoxy group having 1 to 5 carbon atoms, or a fluorine-substituted hydrocarbon group. In the general formula (2), at least one of R _{1 to} R ₄ is a fluorine atom or a fluorine-substituted hydrocarbon group, and in the general formula (3), R _{1 to} R _8. At least one of them is a fluorine atom or a fluorine-substituted hydrocarbon group.

Among these, preferred specific examples of R _{1 to} R ₈ include —H, —CH ₃ , —OCH ₃ , —F, —CF _{3, and the} like. At least in Formula (2) or Formula (3), one of the substituents is, it is preferable that either -F or -CF _3.

Specific examples of Ar ₁ in the general formula (1) when forming the fluorine-containing polyimide include, for example, the following tetravalent acid anhydride residues.

In addition, when forming the fluorine-containing polyimide, considering the transparency of the polyimide and the peelability from other layers, the specific diamine residue that gives Ar ₂ in the general formula (1) is preferably The following are mentioned.

  With such a fluorine-containing polyimide, it is possible to show good separability even at the interface with a polyimide having a structure other than the fluorine-containing polyimide (of course, both the first and second polyimide layers). Is a fluorine-containing polyimide, the separability at the interface is further improved). In addition, in such a fluorine-containing polyimide, when any one of the structural units represented by the following general formula (4) or (5) is contained in a proportion of 80 mol% or more, transparency and releasability are obtained. In addition, since it has low thermal expansion and excellent dimensional stability, it is preferably used as a polyimide for forming the second polyimide layer.

  Here, when the polyimide is a polyimide according to the structure of the general formula (4) or (5), other polyimides that may be added at a ratio of less than 20 mol% at the maximum other than the polyimide are particularly limited. In general, general acid anhydrides and diamines can be used. Among them, pyromellitic dianhydride, 3,3 ", 4,4" -biphenyltetracarboxylic dianhydride, 1,4-cyclohexanedicarboxylic acid, 1,2,3 are preferably used as the acid anhydride. , 4-cyclobutanetetracarboxylic dianhydride, 2,2 "-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, etc. On the other hand, as the diamine, 4,4" -diamino Diphenylsulfone, trans-1,4-diaminocyclohexane, 4,4 "-diaminocyclohexylmethane, 2,2" -bis (4-aminocyclohexyl) -hexafluoropropane, 2,2 "-bis (trifluoromethyl) -4,4 "-diaminobicyclohexane and the like.

  Various polyimides as described above can be obtained by imidizing polyamic acid. Here, the polyamic acid resin solution uses substantially equimolar amounts of diamine and acid dianhydride as raw materials, and is organic. It can be obtained by reacting in a solvent. More specifically, it is obtained by dissolving diamine in an organic polar solvent such as N, N-dimethylacetamide under a nitrogen stream, adding tetracarboxylic dianhydride, and reacting at room temperature for about 5 hours. Can do. The weight average molecular weight of the obtained polyamic acid is preferably 10,000 to 300,000 from the viewpoint of uniform film thickness during coating and mechanical strength of the resulting polyimide film. In addition, the preferable molecular weight range of a polyimide layer is also the same molecular weight range as a polyamic acid.

  In the present invention, preferably, the second polyimide layer 8 is a polyimide having a structural unit represented by the general formula (4) or (5), so that the thermal expansion coefficient is 25 ppm / K or less, advantageously 10 ppm / It can be set as a polyimide layer of K or less, and is convenient as a polyimide base material for forming a display device. Moreover, the polyimide which has these structural units shows the glass transition temperature (Tg) of 300 degreeC or more, and the transmittance | permeability in a wavelength range of 440 nm to 780 nm shows 80% or more.

  As described above, preferably, at least one of the polyimide layers is preferably fluorinated so that they can be easily separated from each other at the interface between the first polyimide layer and the second polyimide layer using a predetermined polyimide. It is preferable to form it from polyimide. By forming at least one polyimide layer from fluorine-containing polyimide, the adhesive strength at the interface between the first polyimide layer and the second polyimide layer is preferably 1 N / m or more and 500 N / m or less, more preferably 5 N / m. m to 300 N / m or less, and more preferably 10 N / m to 200 N / m, so that it has a separability enough to be easily peeled by a human hand. The separated display device is free from defects in appearance such as wrinkles and fractures on the second polyimide layer serving as the polyimide substrate, and the separation surface of the second polyimide layer is a surface roughness obtained by a casting method (general In other words, the surface roughness Ra = 1 to 80 nm is maintained as it is, and the visibility of the display device is not adversely affected.

  According to the present invention, after 1) forming a predetermined display part, after the formation of the predetermined display part, 2) in addition to the method of separating at the interface between the first polyimide layer and the second polyimide layer, The support on the first polyimide layer side was removed, and then separated at the boundary surface between the remaining first polyimide layer and second polyimide layer, and a display unit was provided on the polyimide base material (second polyimide layer). A method for obtaining a display device is also included. In the above method 2), the first polyimide layer 7 and the second polyimide layer 8 are separated from each other after the support 1 is removed. The shapes of the second polyimide layer 8 and the display unit 4 are kept constant during the separation. The first polyimide layer 7 is preferably separated while being fixed. Thereby, the stress concerning the display part 4 can be made small and even when the 2nd polyimide layer 8 is made thinner, the possibility of the damage of the device of the display part 4 can be reduced. Here, in the method 2), the means for removing the support is not particularly limited as long as the display unit 4 and the second polyimide layer 8 are not damaged, but the method described later is used. be able to. That is, in the above description with reference to FIG. 3, an example in which the adhesive layer 6 is used has been shown. However, even in the lamination method, if the first polyimide layer 7 can be directly adhered to the support 1 by means such as thermocompression bonding, the adhesive layer 6 is not necessarily required as shown in FIG. In this case, the support 1 can be removed by the same method as described later.

Next, application examples in the coating method of the present invention will be described.
<Coating method>
FIG. 6 shows a state in which the first polyimide layer 7 and the second polyimide layer 8 are sequentially formed on the support 1 by a coating method, and then the display unit 4 is further laminated. In this method, first, the support 1 is prepared, and a polyamic acid resin solution to be the first polyimide layer 7 is applied thereon, dried by heat treatment, and imidation is completed to form the first polyimide layer 7. Next, a polyamic acid resin solution to be the second polyimide layer 8 is applied onto the first polyimide layer 7, dried by heat treatment, and imidization is completed to form the second polyimide layer 8. In this manner, a substrate in which the first polyimide layer 7 and the second polyimide layer 8 are sequentially formed on the support 1 can be obtained. Then, it is used for the subsequent display portion forming step and subsequent steps. Since the steps after the display portion forming step are the same as those in the laminating method, the details are omitted, and the removal of the support 1 in the method 2) described 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 unit 4 are laminated on the support 1. In the present invention, the support 1 may be removed before the step of separation at the boundary surface between the first polyimide layer 7 and the second polyimide layer 8 from this state. As the first polyimide layer 7, a polyimide material that can be easily peeled off from the support 1 is used as the first polyimide layer 7, or a metal foil such as a copper foil or a metal substrate is used as the support 1, and these are removed with an etching solution. Such a method is exemplified.

  Moreover, you may apply the other well-known method as a method of removing the support body 1. FIG. That is, you may remove the support body 1 by utilizing the laser irradiation in a nonpatent literature 3, or the peeling layer in a nonpatent literature 4. When the support 1 is removed by laser irradiation, the first polyimide layer absorbs the laser, and adverse effects of the laser on the second polyimide layer and the display unit can be prevented. Even when the support 1 is removed using a release layer, the first polyimide layer functions as a stress relaxation layer against the stress generated at the time of release, and prevents a decrease in yield due to damage to the display portion at the time of release. Can do.

  By the way, in JP-T-2007-512568, a yellow film such as polyimide is formed on glass, and then a thin film electronic element is formed on the yellow film, and then the bottom surface of the yellow film is irradiated through the glass with UV laser light. The glass and the yellow film can be peeled off. However, it is also disclosed that, unlike a yellow film, a transparent plastic does not absorb UV laser light, so that an absorption / release layer such as amorphous silicon needs to be provided under the film in advance. On the other hand, JP 2012-511173 A discloses that it is necessary to use a laser having a spectrum in the range of 300 to 410 nm in order to separate the glass from the polyimide film by irradiation with UV laser light. .

  In this invention, when removing a support body from a 1st polyimide layer using a laser beam, it is preferable to use a colored polyimide for a 1st polyimide layer. It is one of the preferred embodiments of the present invention that the first polyimide layer is a colored polyimide and the second polyimide layer is a transparent polyimide.

  In the coating method, a polyamic acid resin solution to be the first polyimide layer 7 is applied on the support 1 and heat-treated. At this time, the first polyimide layer should be imidized by sufficient heat treatment. This is preferable for easy separation of the two polyimide layers. Also in the coating method, as described in the laminating method, it is desirable to use polyimide having a specific chemical structure for at least one of the first or second polyimide layer. The first polyimide layer and the second polyimide layer may be polyimide having the same chemical structure.

  In the coating method, both the first polyimide layer and the second polyimide layer are obtained by applying a resin solution and then drying or drying / curing after applying the resin solution. It is preferable that the heating time in the high temperature heating temperature range from the temperature 20 ° C. lower than the temperature (maximum temperature reached) to the maximum temperature (hereinafter referred to as the high temperature holding time) is as short as necessary characteristics can be obtained. In the first place, the purpose of holding the first and / or second polyimide layer in the high temperature range in the coating method is to obtain the characteristics required for the original polyimide layer by completely removing the residual solvent and promoting the orientation of the polyimide resin. Because. However, in particular, when the high temperature holding time of the second polyimide layer is long, the peelability from the first polyimide layer tends to decrease, or the transmittance tends to decrease due to coloring or the like. The optimum high temperature holding time varies depending on the heating method, the polyimide thickness, and the type of polyimide, but is preferably 0.5 minutes or more and less than 60 minutes, and more preferably 0.5 minutes or more and less than 30 minutes.

Next, an application example in the combined method of film lamination and resin solution coating of the present invention will be described.
<Combination method>
FIG. 8 shows a state in which a first polyimide layer 7 cut slightly smaller than the support 1 is pasted on the support 1 with an adhesive layer 6, and a second polyimide layer 8 and a display unit 4 are laminated thereon. It represents.
In this method, first, the support 1 is prepared, and a polyimide film to be the first polyimide layer 7 is adhered thereon with the adhesive layer 6. In this respect, the same method can be applied using the same polyimide film as the above-mentioned laminating method.

  Next, a polyamic acid resin solution to be the second polyimide layer 8 is applied on the first polyimide layer 7 and dried by heat treatment to complete imidization, whereby the second polyimide layer 8 is obtained. In this respect, the same method can be applied using the same resin solution as the coating method. In this manner, a substrate in which the first polyimide layer 7 and the second polyimide layer 8 are sequentially formed on the support 1 can be obtained. Then, it is used for the subsequent display portion forming step and subsequent steps. Since the steps after the display portion forming step are the same as described above, they are omitted.

  In the combined method, the first polyimide layer 7 and the support 1 are bonded together, and then the entire surface of the first polyimide layer 7 is covered with a polyamic acid resin solution that gives the second polyimide layer 8 in a varnish state. Apply. The applied polyamic acid resin solution is dried by heat treatment and imidized to form the second polyimide layer 8. In this state, as shown in FIG. At least a portion of the second polyimide layer 8 that is larger than the polyimide layer and not in contact with the first polyimide layer 7 is in contact with the support 1. That is, a part of the second polyimide layer 8 projects from the peripheral edge of the first polyimide layer 7 so that the projecting part of the second polyimide layer 8 is fixed to the support 1. Also in this method, the second polyimide layer 8 and the first polyimide layer 7 are configured to be easily peeled off. However, the second polyimide layer 8 and the support 1 are stronger by the overhanging portion of the second polyimide layer 8. Therefore, it is possible to increase the adhesion around the support and to secure more stability during the process. In addition, after forming a display part, what is necessary is just to carry out similarly to the cutting process as mentioned above, for example, as shown in FIG. 9, the display part 4 and the 2nd polyimide along the cutting line 5 which cuts off the display part 4 If the layer 8 is cut and separated at the boundary surface between the first polyimide layer 7 and the second polyimide layer 8, a display device including the display unit 4 on the polyimide substrate made of the second polyimide layer 8 can be obtained. it can.

  In the present invention, including the case where the above three methods are employed and the case where other methods are employed, the first polyimide layer is separated later, so it does not contribute to the function of the display device. Considering the temperature change during the manufacturing process of the display unit, the characteristics until separation is an important factor. From such a viewpoint, 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 such a first polyimide layer include, for example, a polyimide having as a main component a structural unit composed of biphenyltetracarboxylic dianhydride and phenylenediamine. As a commercial item, for example, Upilex-S manufactured by Ube Industries, Ltd., Kapton manufactured by Toray DuPont Co., Ltd., and Toyobo Co., Ltd. can be used.

  In the present invention, when the display portion is formed, oxygen, water vapor, or the like made of an inorganic oxide film such as silicon oxide, aluminum oxide, silicon carbide, silicon oxide carbide, silicon carbonitride, silicon nitride, or silicon nitride oxide A gas barrier layer having a barrier property against the above may be interposed. At that time, in order to reduce warpage of the obtained display device, it is preferable that the difference in thermal expansion coefficient between the second polyimide layer and the gas barrier layer is 10 ppm / K or less.

  In order to make it possible to easily separate the first polyimide layer 7 and the second polyimide layer 8 from the boundary surface by a method other than using a polyimide having a specific chemical structure for the first or second polyimide layer. For example, the first polyimide layer 7 is heat-treated to change the surface state of the first polyimide layer 7 to reduce the surface wettability, and then the second polyimide layer 8 is quickly applied. The method of using a film is mentioned. The appropriate temperature for this heat treatment varies depending on the type of the first polyimide layer 7, but when the first polyimide layer 7 is a polyimide film such as Kapton manufactured by Toray DuPont Co., Ltd. or Upilex manufactured by Ube Industries, Ltd., 300 ° C. or more and 500 ° C. C. or lower is preferable.

  In this invention, after forming a predetermined display part, in the method of separating at the boundary surface between the first polyimide layer and the second polyimide layer, a laminate of the support and the first polyimide layer separated from the second polyimide layer The laminate of the support and the first polyimide layer may be reused by forming the second polyimide layer again on the first polyimide layer side. When repeatedly used, after separating the second polyimide layer, the laminate of the support and the first polyimide layer may be washed. Alternatively, the second polyimide layer may be applied after the laminate of the support and the first polyimide layer is heat-treated to reduce the wettability of the surface of the first polyimide layer.

  In addition, as another method of repeatedly using the laminate of the support and the first polyimide layer, the second polyimide layer is separated, and the first polyimide layer side of the laminate of the support and the first polyimide layer is again, A method of forming one polyimide layer and then forming a second polyimide layer is also possible.

  Furthermore, in the present invention, the support removed from the first polyimide layer may be reused. Prior to reuse, the support may be cleaned, heat-treated, or surface-treated.

  Hereinafter, the present invention will be described more specifically based on examples. In addition, this invention is not limited to the content of the following Example.

In the following examples, methods for evaluating physical properties and the like are shown.
[Transmissivity (%)]
The average value of the light transmittance from 440 nm to 780 nm was determined for a polyimide film (50 mm × 50 mm) with a U4000 spectrophotometer.

[Glass transition temperature (Tg)]
The glass transition temperature was measured at a rate of 10 ° C./min from room temperature to 400 ° C. while applying a 1 Hz vibration using a 10 mm wide sample using a viscoelasticity analyzer (RSA-II manufactured by Rheometric Science Effy Co., Ltd.). It was determined from the maximum loss tangent (Tan δ) when the temperature was raised at.

[Coefficient of thermal expansion (CTE)]
Tensile test of polyimide film with a size of 3mm x 15mm in a temperature range from 30 ° C to 260 ° C at a constant heating rate (20 ° C / min) while applying a 5.0g load with a thermomechanical analysis (TMA) device And the coefficient of thermal expansion (× 10 ⁻⁶ / K) was measured from the amount of elongation of the polyimide film with respect to temperature.

[Example 1]
Curing a polyamic acid resin solution obtained from PDA (1,4-phenylenediamine) and BPDA (3,3 ", 4,4" -biphenyltetracarboxylic dianhydride) on a glass substrate as a support It applied so that it might become the application | coating area of 20 micrometers and 300 mm x 380 mm later, and the solvent (DMAc: N, N- dimethylacetamide) in a resin solution was heat-dried at 130 degreeC, and was removed. Next, it was imidized by heat treatment from 160 ° C. to 360 ° C. at a heating rate of about 1 ° C./min to form a first polyimide layer (surface roughness Ra = 1.3 nm, Tg = 355 ° C.) having a thickness of 20 μm. .

  On this first polyimide layer, PMDA (pyromellitic dianhydride), 6FDA (2,2 "-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride) and TFMB (2,2"- A resin solution of polyamic acid obtained from bis (trifluoromethyl) -4,4 "-diaminobiphenyl) is 310 mm × 390 mm larger than the application area of the first polyimide layer and covering the entire first polyimide layer The coating area was applied so that the thickness after curing was 25 μm, and the solvent (DMAc: N, N-dimethylacetamide) in the resin solution was removed by heating and drying at 130 ° C. Next, 160 ° C. to 360 ° C. The second polyimide layer having a thickness of 25 μm was formed by heat treatment at a heating rate of about 20 ° C./min until the high temperature holding time was 1 minute. Contact in the synthesis of the polyamic acid, dianhydride component diamine component and the acid is an approximately equimolar ratio of PMDA / 6FDA was 85/15.

  In this way, a laminate in which the first and second polyimide layers were sequentially laminated on the glass was formed, and an EL element serving as a display unit was formed on the second polyimide layer side of the laminate. Then, the second polyimide layer is cut so as to surround the display portion, the interface between the first polyimide layer and the second polyimide layer is peeled and separated, and the EL element is provided on the polyimide base material composed of the second polyimide layer. A display device was obtained. At this time, between the first polyimide layer and the second polyimide layer can be easily peeled off by a person without using any means such as laser peeling without damaging the display device such as TFT and electrode. Could be separated. The peel strength between the first polyimide layer and the second polyimide layer was 3.5 N / m. In addition, in the said Example, the linear expansion coefficient of the 1st polyimide layer was 12.0 ppm / K, and the linear expansion coefficient of the 2nd polyimide layer was 9.7 ppm / K. The transmittance of the second polyimide layer in the wavelength region of 440 nm to 780 nm was 83.5%.

[Example 2]
Curing a polyamic acid resin solution obtained from PDA (1,4-phenylenediamine) and BPDA (3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride) on a glass substrate as a support The coating was applied so that the subsequent thickness was 20 μm and a coating area of 310 mm × 390 mm, and the solvent (DMAc: N, N-dimethylacetamide) in the resin solution was dried by heating at 120 ° C. to remove. Next, it was imidized by heat treatment from 130 ° C. to 360 ° C. at a heating rate of about 1 ° C./min to form a first polyimide layer (surface roughness Ra = 1.3 nm, Tg = 355 ° C.) having a thickness of 25 μm. .

  On this first polyimide layer, PMDA (pyromellitic dianhydride), 6FDA (2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride) and TFMB (2,2'- A resin solution of polyamic acid obtained from bis (trifluoromethyl) -4,4′-diaminobiphenyl) is applied on the first polyimide layer so as to have a coating area of 310 mm × 390 mm and a thickness after curing of 5 μm. After coating, the solvent (DMAc: N, N-dimethylacetamide) in the resin solution was removed by heating and drying at 130 ° C. Next, it imidized by heat-treating at a rate of temperature increase of about 20 ° C./min from 160 ° C. to 360 ° C. to form a second polyimide layer having a thickness of 5 μm. In the synthesis of the polyamic acid, the diamine component and the acid dianhydride component were approximately equimolar, and the PMDA / 6FDA ratio was 60/40.

  In this way, a laminate in which the first and second polyimide layers were sequentially laminated on the glass was formed, and an EL element serving as a display unit was formed on the second polyimide layer side of the laminate. Then, the first polyimide layer and the second polyimide layer are cut off in the thickness direction of the first polyimide layer and the second polyimide layer so as to surround the display portion, and the glass on the first polyimide layer side is peeled off and removed. A display device having an EL element on a polyimide base material composed of a second polyimide layer was obtained by peeling at the interface with the layer. At this time, between the glass and the first polyimide layer, and between the first polyimide layer and the second polyimide layer, means such as laser peeling without damaging the display device such as TFT and electrode. It was possible to separate easily by pulling it off without using. The peel strength between the first polyimide layer and the second polyimide layer was 4.0 N / m. In the above examples, the linear expansion coefficient of the first polyimide layer was 7.0 ppm / K, and the linear expansion coefficient of the second polyimide layer was 20.4 ppm / K. The transmittance of the second polyimide layer in the wavelength region of 440 nm to 780 nm was 86.7%.

(Example 3)
In order to reuse the laminate of the support and the first polyimide layer separated and separated from the second polyimide layer in Example 1, after removing the remaining peripheral portion of the second polyimide layer, it was washed with pure water, Further, heat treatment was performed for two minutes at each temperature of 100 ° C., 200 ° C., 300 ° C., and 360 ° C.

  On this first polyimide layer, the polyamic acid resin solution was applied in the same manner as the second polyimide layer of Example 1, and heat-dried at 130 ° C., and then about 20 ° C./min from 160 ° C. to 360 ° C. The temperature was raised at a rate and held at 360 ° C. for 60 minutes to form a second polyimide layer having a thickness of 25 μm. The high temperature holding time at this time was 61 minutes.

  Thus, it was set as the laminated body by which the 1st polyimide layer and the 2nd polyimide layer were laminated | stacked sequentially on glass, and the display apparatus was obtained in the procedure similar to Example 1. FIG. The peel strength between the first polyimide layer and the second polyimide layer was 10.0 N / m and could be easily separated manually. The linear expansion coefficient of the second polyimide layer was 9.3 ppm / K, and the transmittance of the second polyimide layer in the wavelength region of 440 nm to 780 nm was 78.5%.

Example 4
On a glass substrate as a support, 17.70 g of m-TB (2,2′-dimethylbenzidine), 4.3 g of TPE-R (1,3-bis (4-aminophenoxy) benzene and PMDA (Pyromerit Acid dianhydride) 17.20 g, BPDA (3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride) 5.8 g of polyamic acid resin solution obtained after curing had a thickness of 25 μm, 310 mm X The coating area was 390 mm, and the solvent (DMAc: N, N-dimethylacetamide) in the resin solution was removed by heating and drying at 120 ° C. Next, from about 130 ° C. to 160 ° C. The film was imidized by heat treatment at a heating rate of 1 minute to form a first polyimide layer (surface roughness Ra = 1.0 nm, Tg = 360 ° C.) having a thickness of 25 μm.

  On this 1st polyimide layer, the polyamic acid resin solution is apply | coated so that it may become an application area of 306 mm x 386 mm similarly to the 2nd polyimide layer of Example 1, and it heat-drys at 130 degreeC, then, 160 degreeC To 360 ° C. at a rate of about 20 ° C./min and maintained at 360 ° C. for 30 minutes to form a second polyimide layer having a thickness of 25 μm. The high temperature holding time at this time was 31 minutes.

  Thus, it was set as the laminated body by which the 1st polyimide layer and the 2nd polyimide layer were laminated | stacked sequentially on glass, and the display apparatus was obtained in the procedure similar to Example 2. FIG. The peel strength between the first polyimide layer and the second polyimide layer was 110 N / m, and could be separated manually. 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. The transmittance of the second polyimide layer in the wavelength region of 440 nm to 780 nm was 80.5%.

(Example 5)
The thickness of the polyamic acid resin solution obtained from PDA (1,4-phenylenediamine) and BPDA (3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride) on the copper foil is 20 μm after curing. The solvent (DMAc: N, N-dimethylacetamide) in the resin solution was removed by heating and drying at 130 ° C. Next, the film was imidized by heat treatment from 160 ° C. to 360 ° C. at a heating rate of about 1 ° C./min, and a 20 μm thick first polyimide layer (surface roughness Ra = 1.3 nm, Tg = 355 ° C.) was copper foil. Formed on top.

  On this first polyimide layer, PMDA (pyromellitic dianhydride), 6FDA (2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride) and TFMB (2,2'- A resin solution of polyamic acid obtained from bis (trifluoromethyl) -4,4′-diaminobiphenyl) was applied so that the thickness after curing was 25 μm, and the solvent (DMAc: N, N— Dimethylacetamide) was removed by heating and drying at 130 ° C. Next, the film was imidized by heat treatment from 160 ° C. to 360 ° C. at a rate of temperature increase of about 20 ° C./min to form a second polyimide layer having a thickness of 25 μm. In the synthesis of the polyamic acid, the diamine component and the acid dianhydride component were approximately equimolar, and the PMDA / 6FDA ratio was 85/15.

  The copper foil portion of the laminate composed of this copper foil / first polyimide layer / second polyimide layer was removed by ferric chloride etching to obtain a laminated film composed of the first polyimide layer / second polyimide layer.

  This laminated film was adhered to a glass substrate as a support with an epoxy resin adhesive, and then an EL element as a display portion was formed on the second polyimide layer side. Then, the interface of a 1st polyimide layer and a 2nd polyimide layer was isolate | separated by peeling, and the display apparatus which has an EL element on a polyimide base material was obtained. The first polyimide layer and the second polyimide layer could be easily separated without damaging the display device such as TFT and electrode. In addition, in the said Example, the linear expansion coefficient of the 1st polyimide layer was 12.0 ppm / K, and the linear expansion coefficient of the 2nd polyimide layer was 9.7 ppm / K. The transmittance of the second polyimide layer in the wavelength region of 440 nm to 780 nm was 83.5%.

1 Glass substrate 2 Release layer 3 Polyimide layer 4 Display part (TFT / organic EL panel part)
5 Cutting line 6 Adhesive layer 7 First polyimide layer 8 Second polyimide layer 9 Cutting region
10 Cut surface

As a result of studies conducted by the present inventors to solve the above-mentioned problems, both of the first resin layer and the second resin layer made of polyimide are laminated on the support, and a predetermined amount is formed on the second resin layer. By forming the display part and then separating at the boundary surface between the first resin layer and the second resin layer, a display device provided with the display part on the resin substrate made of the second resin layer can be obtained very easily. The present invention has been completed.
That is, the gist of the present invention is as follows.

［式中、Ａｒ₁は芳香環を有する４価の有機基を表し、Ａｒ₂は下記一般式（２）又は（３）で表される２価の有機基である。

〔ここで、一般式（２）又は一般式（３）におけるＲ₁〜Ｒ₈は、互いに独立に水素原子、フッ素原子、炭素数１〜５までのアルキル基若しくはアルコキシ基、又はフッ素置換炭化水素基であり、一般式（２）にあってはＲ₁〜Ｒ₄のうち、また、一般式（３）にあってはＲ₁〜Ｒ₈のうち、それぞれ少なくとも一つはフッ素原子又はフッ素置換炭化水素基である。〕］ (1) A laminated film in which a first polyimide layer and a second polyimide layer are directly laminated and a support are bonded to each other through an adhesive layer between the first polyimide layer surface of the laminated film and one surface of the support. After that, a predetermined display part is formed on the laminated film, and then separated at the interface between the first polyimide layer and the second polyimide layer, and the display part is provided on the polyimide base material composed of the second polyimide layer. A display device manufacturing method characterized by obtaining a display device.
(2) After the first polyimide layer and the second polyimide layer are formed on the support , a predetermined display portion is further formed on the second polyimide layer , and then the support is removed , and then the first polyimide layer And a second polyimide layer, and a display device having a display unit on a polyimide base material composed of the second polyimide layer is obtained .
(3) The method for manufacturing a display device according to (2) , wherein the first polyimide layer is formed by laminating a polyimide film, and the second polyimide layer is formed by applying a resin solution of polyimide or a polyimide precursor.
(4) The method for producing a display device according to (2) , wherein the first polyimide layer and the second polyimide layer are formed by applying and heating a resin solution of polyimide or a polyimide precursor.
(5) After forming the first polyimide layer and the second polyimide layer on the support, a predetermined display portion is further formed on the second polyimide layer, and then the boundary between the first polyimide layer and the second polyimide layer. A method of manufacturing a display device that is separated by a surface and obtains a display device having a display unit on a polyimide substrate made of a second polyimide layer, wherein a part of the second polyimide layer is a peripheral portion of the first polyimide layer A manufacturing method of a display device, characterized in that the protruding portion of the second polyimide layer is fixed to a support .
(6) After forming the first polyimide layer and the second polyimide layer on the support, a predetermined display portion is further formed on the second polyimide layer, and then the boundary between the first polyimide layer and the second polyimide layer. A method of manufacturing a display device that is separated by a surface and obtains a display device having a display unit on a polyimide substrate made of a second polyimide layer, the first polyimide layer or one of the second polyimide layers A method for manufacturing a display device, characterized in that a part thereof protrudes from a peripheral edge portion of another layer .
(7) After forming the first polyimide layer and the second polyimide layer on the support, a predetermined display portion is further formed on the second polyimide layer, and then the boundary between the first polyimide layer and the second polyimide layer. A display device manufacturing method for obtaining a display device provided with a display unit on a polyimide substrate made of a second polyimide layer, wherein the first polyimide layer is cut along the outer periphery of the display unit. And then separating the first polyimide layer and the second polyimide layer .
(8) When the second polyimide layer is formed by applying a polyimide or polyimide precursor resin solution and then heating, the high temperature holding time of the second polyimide layer is less than 60 minutes. (3) or ( A method for manufacturing a display device according to 4) .
(9) The method for manufacturing a display device according to any one of (1) to (8) , wherein the support is a glass substrate.
(10) The manufacturing method of the display device according to any one of (1) to (9) , wherein the first polyimide layer has a thermal expansion coefficient of 25 ppm / K or less.
(11) The method for manufacturing a display device according to any one of (1) to (10) , wherein the second polyimide layer has a thermal expansion coefficient of 25 ppm / K or less.
(12) The method for manufacturing a display device according to any one of (1) to (11) , wherein the second polyimide layer has a transmittance of 80% or more in a wavelength region of 440 nm to 780 nm.
(13) The display according to any one of (1) to (12) , wherein the display unit is formed through a gas barrier layer, and a difference in thermal expansion coefficient between the second polyimide layer and the gas barrier layer is 10 ppm / K or less. Device manufacturing method.
(14) The method for manufacturing a display device according to any one of (1) to (13) , wherein the display unit is a color filter layer.
(15) The method for manufacturing a display device according to any one of (1) to (14) , wherein a peel strength between the first polyimide layer and the second polyimide layer is 200 N / m or less.
(16) The display according to any one of (1) to (15) , wherein at least one of the first polyimide layer or the second polyimide layer is made of polyimide having a structural unit represented by the following general formula (1). Device manufacturing method.

[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).

[Wherein, R _{1 to} R ₈ in the general formula (2) or the general formula (3) are each independently a hydrogen atom, a fluorine atom, an alkyl group or an alkoxy group having 1 to 5 carbon atoms, or a fluorine-substituted hydrocarbon. In the general formula (2), at least one of R _{1 to} R ₄ and R _{1 to} R _{8 in} the general formula (3) is a fluorine atom or a fluorine-substituted group. It is a hydrocarbon group. ]]

According to the present invention, the first resin layer and the second resin layer made of polyimide are both laminated on the support, thereby ensuring the handleability and dimensional stability while maintaining a predetermined display. The part can be formed. After the display portion is formed, the display device can be obtained very easily because it can be easily separated using the interface between the first resin layer and the second resin layer without requiring laser irradiation or the like. Can do. In addition, the support is reused in the manufacture of the display device because there is no influence on the second resin layer and the display portion which become the resin base material after separation, and the support is not damaged. It is also possible to make a significant contribution to manufacturing cost reduction.

［式中、Ａｒ ₁ は下記いずれかの芳香環を有する４価の有機基である。

式中、Ａｒ ₂ は下記一般式（２）又は（３）で表される２価の有機基である。

〔ここで、一般式（２）又は一般式（３）におけるＲ ₁ 〜Ｒ ₈ は、互いに独立に水素原子、フッ素原子、炭素数１〜５までのアルキル基若しくはアルコキシ基、又はフッ素置換炭化水素基であり、一般式（２）にあってはＲ ₁ 〜Ｒ ₄ のうち、また、一般式（３）にあってはＲ ₁ 〜Ｒ ₈ のうち、それぞれ少なくとも一つはフッ素原子又はフッ素置換炭化水素基である。〕］
（６）支持体上に第一ポリイミド層と第二ポリイミド層とが積層されるように形成した後に、更に第二ポリイミド層上に所定の表示部を形成し、その後、第一ポリイミド層と第二ポリイミド層との境界面で分離して、第二ポリイミド層からなるポリイミド基材上に表示部を備えた表示装置を得る表示装置の製造方法であって、第一ポリイミド層の一部が、は第二ポリイミド層の周縁部より張り出すようにすることを特徴とする表示装置の製造方法。
（７）支持体上に第一ポリイミド層と第二ポリイミド層とが積層されるように形成した後に、更に第二ポリイミド層上に所定の表示部を形成し、その後、第一ポリイミド層と第二ポリイミド層との境界面で分離して、第二ポリイミド層からなるポリイミド基材上に表示部を備えた表示装置を得る表示装置の製造方法であって、第一ポリイミド層、又は第二ポリイミド層の少なくとも一方が、下記一般式（１）で表される構造単位を有するポリイミドからなり、表示部の外周に沿って第二ポリイミド層を完全に切断し第一ポリイミド層まで切れ目を入れた後、第一ポリイミド層と第二ポリイミド層との分離を行なうことを特徴とする表示装置の製造方法。

［式中、Ａｒ ₁ は下記いずれかの芳香環を有する４価の有機基である。

式中、Ａｒ ₂ は下記一般式（２）又は（３）で表される２価の有機基である。

〔ここで、一般式（２）又は一般式（３）におけるＲ ₁ 〜Ｒ ₈ は、互いに独立に水素原子、フッ素原子、炭素数１〜５までのアルキル基若しくはアルコキシ基、又はフッ素置換炭化水素基であり、一般式（２）にあってはＲ ₁ 〜Ｒ ₄ のうち、また、一般式（３）にあってはＲ ₁ 〜Ｒ ₈ のうち、それぞれ少なくとも一つはフッ素原子又はフッ素置換炭化水素基である。〕］
（８）第二ポリイミド層の形成をポリイミド又はポリイミド前駆体の樹脂溶液を塗布したのち加熱することで行う際に、第二ポリイミド層の高温保持時間が６０分未満である、（３）又は（４）に記載の表示装置の製造方法。
（９）支持体がガラス基板である、（１）〜（８）のいずれかに記載の表示装置の製造方法。
（１０）第一ポリイミド層の熱膨張係数が２５ｐｐｍ／Ｋ以下である、（１）〜（９）のいずれかに記載の表示装置の製造方法。
（１１）第二ポリイミド層の熱膨張係数が２５ｐｐｍ／Ｋ以下である、（１）〜（１０）のいずれかに記載の表示装置の製造方法。
（１２）第二ポリイミド層は、４４０ｎｍから７８０ｎｍの波長領域での透過率が８０％以上である、（１）〜（１１）のいずれかに記載の表示装置の製造方法。
（１３）表示部がガスバリア層を介して形成され、第二ポリイミド層とガスバリア層との熱膨張係数の差が１０ｐｐｍ／Ｋ以下である、（１）〜（１２）のいずれかに記載の表示装置の製造方法。
（１４）表示部がカラーフィルター層である、（１）〜（１３）のいずれかに記載の表示装置の製造方法。
（１５）第一ポリイミド層と第二ポリイミド層との剥離強度が２００Ｎ／ｍ以下である、（１）〜（１４）のいずれか記載の表示装置の製造方法。
（１６）第一ポリイミド層、又は第二ポリイミド層の少なくとも一方が、下記一般式（１）で表される構造単位を有するポリイミドからなる、（１）〜（４）、（６）、及び（８）〜（１５）のいずれかに記載の表示装置の製造方法。

［式中、Ａｒ₁は下記いずれかの芳香環を有する４価の有機基である。

式中、Ａｒ₂は下記一般式（２）又は（３）で表される２価の有機基である。

〔ここで、一般式（２）又は一般式（３）におけるＲ₁〜Ｒ₈は、互いに独立に水素原子、フッ素原子、炭素数１〜５までのアルキル基若しくはアルコキシ基、又はフッ素置換炭化水素基であり、一般式（２）にあってはＲ₁〜Ｒ₄のうち、また、一般式（３）にあってはＲ₁〜Ｒ₈のうち、それぞれ少なくとも一つはフッ素原子又はフッ素置換炭化水素基である。〕］ (1) The laminated film in which the first polyimide layer and the second polyimide layer are directly laminated and the support are bonded to each other through the adhesive layer between the first polyimide layer surface of the laminated film and the one surface of the support. Later, a predetermined display portion was formed on the laminated film, and then separated at the interface between the first polyimide layer and the second polyimide layer, and the display portion was provided on the polyimide base material composed of the second polyimide layer. A method for manufacturing a display device, comprising: obtaining a display device.
(2) After the first polyimide layer and the second polyimide layer are formed on the support, a predetermined display portion is further formed on the second polyimide layer, and then the support is removed, and then the first polyimide layer And a second polyimide layer, and a display device having a display unit on a polyimide base material composed of the second polyimide layer is obtained.
(3) The method for manufacturing a display device according to (2), wherein the first polyimide layer is formed by laminating a polyimide film, and the second polyimide layer is formed by applying a resin solution of polyimide or a polyimide precursor.
(4) The method for manufacturing a display device according to (2), wherein the first polyimide layer and the second polyimide layer are formed by applying and heating a resin solution of polyimide or a polyimide precursor.
(5) After the first polyimide layer and the second polyimide layer are formed to be laminated on the support, a predetermined display portion is further formed on the second polyimide layer, and then the first polyimide layer and the second polyimide layer are formed. A method of manufacturing a display device that is separated at a boundary surface between two polyimide layers and obtains a display device having a display unit on a polyimide base material composed of a second polyimide layer, the first polyimide layer or the second polyimide At least one of the layers is made of polyimide having a structural unit represented by the following general formula (1), and a part of the second polyimide layer protrudes from the peripheral edge of the first polyimide layer. A method for manufacturing a display device, characterized in that an overhanging portion of the display device is fixed to a support.

[Wherein Ar ₁ is a tetravalent organic group having any of the following aromatic rings.

In the formula, Ar ₂ is a divalent organic group represented by the following general formula (2) or (3).

[Wherein R _{1 to} R ₈ in the general formula (2) or the general formula (3) are each independently a hydrogen atom, a fluorine atom, an alkyl group or an alkoxy group having 1 to 5 carbon atoms, or a fluorine-substituted hydrocarbon. In the general formula (2), at least one of R _{1 to} R ₄ and R _{1 to} R _{8 in} the general formula (3) is a fluorine atom or a fluorine-substituted group. It is a hydrocarbon group. ]]
(6) After the first polyimide layer and the second polyimide layer are formed to be laminated on the support, a predetermined display portion is further formed on the second polyimide layer, and then the first polyimide layer and the second polyimide layer are formed. A method of manufacturing a display device that is separated at the boundary surface between two polyimide layers and obtains a display device provided with a display unit on a polyimide base material composed of a second polyimide layer, wherein a part of the first polyimide layer is Is a method of manufacturing a display device, characterized by projecting from the peripheral edge of the second polyimide layer.
(7) After the first polyimide layer and the second polyimide layer are laminated on the support, a predetermined display portion is further formed on the second polyimide layer, and then the first polyimide layer and the second polyimide layer are formed. A method of manufacturing a display device that is separated at a boundary surface between two polyimide layers and obtains a display device having a display unit on a polyimide base material composed of a second polyimide layer, the first polyimide layer or the second polyimide After at least one of the layers is made of polyimide having a structural unit represented by the following general formula (1), the second polyimide layer is completely cut along the outer periphery of the display portion, and the first polyimide layer is cut. A method for producing a display device, wherein the first polyimide layer and the second polyimide layer are separated.

[Wherein Ar ₁ is a tetravalent organic group having any of the following aromatic rings.

In the formula, Ar ₂ is a divalent organic group represented by the following general formula (2) or (3).

[Wherein, R _{1 to} R ₈ in the general formula (2) or the general formula (3) are each independently a hydrogen atom, a fluorine atom, an alkyl group or an alkoxy group having 1 to 5 carbon atoms, or a fluorine-substituted hydrocarbon. In the general formula (2), at least one of R _{1 to} R ₄ and R _{1 to} R _{8 in} the general formula (3) is a fluorine atom or a fluorine-substituted group. It is a hydrocarbon group. ]]
(8) When the second polyimide layer is formed by applying a polyimide or polyimide precursor resin solution and then heating, the high temperature holding time of the second polyimide layer is less than 60 minutes, (3) or ( A method for manufacturing a display device according to 4).
(9) The method for manufacturing a display device according to any one of (1) to (8), wherein the support is a glass substrate.
(10) The manufacturing method of the display apparatus in any one of (1)-(9) whose thermal expansion coefficient of a 1st polyimide layer is 25 ppm / K or less.
(11) The method for manufacturing a display device according to any one of (1) to (10), wherein the second polyimide layer has a thermal expansion coefficient of 25 ppm / K or less.
(12) The method for manufacturing a display device according to any one of (1) to (11), wherein the second polyimide layer has a transmittance in a wavelength region of 440 nm to 780 nm of 80% or more.
(13) The display according to any one of (1) to (12), wherein the display unit is formed through a gas barrier layer, and a difference in thermal expansion coefficient between the second polyimide layer and the gas barrier layer is 10 ppm / K or less. Device manufacturing method.
(14) The method for manufacturing a display device according to any one of (1) to (13), wherein the display unit is a color filter layer.
(15) The method for manufacturing a display device according to any one of (1) to (14), wherein the peel strength between the first polyimide layer and the second polyimide layer is 200 N / m or less.
(16) At least one of the first polyimide layer or the second polyimide layer is made of polyimide having a structural unit represented by the following general formula (1), (1) to ( 4), (6), and ( The manufacturing method of the display apparatus in any one of 8)-( 15).

[Wherein Ar ₁ is a tetravalent organic group having any of the following aromatic rings .

In the formula, Ar ₂ is a divalent organic group represented by the following general formula (2) or (3).

[Wherein, R _{1 to} R ₈ in the general formula (2) or the general formula (3) are each independently a hydrogen atom, a fluorine atom, an alkyl group or an alkoxy group having 1 to 5 carbon atoms, or a fluorine-substituted hydrocarbon. In the general formula (2), at least one of R _{1 to} R ₄ and R _{1 to} R _{8 in} the general formula (3) is a fluorine atom or a fluorine-substituted group. It is a hydrocarbon group. ]]

Claims (19)

  In a state where the first resin layer and the second resin layer are laminated on the support, a predetermined display portion is formed on the second resin layer, and then the boundary surface between the first resin layer and the second resin layer To obtain a display device having a display unit on a resin substrate made of the second resin layer.   After laminating the laminated film in which the first resin layer and the second resin layer are directly laminated and the support, the first resin layer surface of the laminated film and one surface of the support are bonded together via an adhesive layer, and then laminated. A predetermined display portion is formed on a film, and then separated at the boundary surface between the first resin layer and the second resin layer, and a display device having a display portion on a resin substrate made of the second resin layer The method of manufacturing a display device according to claim 1, wherein the display device is obtained.   The manufacturing method of the display apparatus of Claim 2 with which the 1st resin layer and 2nd resin layer which comprise a laminated film each consist of polyimide.   After the first polyimide layer and the second polyimide layer are formed on the support, a predetermined display portion is further formed, and then the second polyimide layer is separated at the boundary surface between the first polyimide layer and the second polyimide layer. The method for manufacturing a display device according to claim 1, wherein a display device having a display unit on a polyimide base material composed of layers is obtained.   After forming the predetermined display portion, after removing the support, it is separated at the boundary surface between the first polyimide layer and the second polyimide layer to obtain a display device having a display portion on the polyimide base material. The manufacturing method of the display apparatus of Claim 4.   The method for manufacturing a display device according to claim 4 or 5, wherein the first polyimide layer is formed by laminating a polyimide film, and the second polyimide layer is formed by applying a resin solution of polyimide or a polyimide precursor.   The manufacturing method of the display apparatus of Claim 4 or 5 which forms a 1st polyimide layer and a 2nd polyimide layer by apply | coating and heating the resin solution of a polyimide or a polyimide precursor.   A part of the second polyimide layer protrudes from the peripheral edge of the first polyimide layer, and the protruding part of the second polyimide layer is fixed to the support. The manufacturing method of the display apparatus of description.   The manufacturing method of the display apparatus in any one of Claims 4-7 which makes a part of one layer of the 1st polyimide layer or the 2nd polyimide layer protrude from the peripheral part of another layer.   The manufacturing method of the display apparatus in any one of Claims 4-9 which isolate | separates a 1st resin layer and a 2nd resin layer after making a cut | interruption in a 1st resin layer along the outer periphery of a display part.   The high temperature holding time of the second polyimide layer is less than 60 minutes when the second polyimide layer is formed by heating after applying a resin solution of polyimide or a polyimide precursor. Manufacturing method of display device.   The manufacturing method of the display apparatus in any one of Claims 1-11 whose support body is a glass substrate.   The manufacturing method of the display apparatus in any one of Claims 1-12 whose thermal expansion coefficient of a 1st resin layer is 25 ppm / K or less.   The manufacturing method of the display apparatus in any one of Claims 1-13 whose thermal expansion coefficient of a 2nd resin layer is 25 ppm / K or less.   The method for manufacturing a display device according to claim 1, wherein the second resin layer has a transmittance of 80% or more in a wavelength region from 440 nm to 780 nm.   The method for manufacturing a display device according to claim 1, wherein the display unit is formed through a gas barrier layer, and a difference in thermal expansion coefficient between the second resin layer and the gas barrier layer is 10 ppm / K or less.   The manufacturing method of the display apparatus in any one of Claims 1-16 whose display part is a color filter layer.   The manufacturing method of the display apparatus in any one of Claims 1-17 whose peeling strength of a 1st resin layer and a 2nd resin layer is 200 N / m or less. The manufacturing method of the display apparatus in any one of Claims 1-18 in which at least one of a 1st resin layer or a 2nd resin layer consists of a polyimide which has a structural unit represented by following General formula (1).

[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).

[Wherein R _{1 to} R ₈ in the general formula (2) or the general formula (3) are each independently a hydrogen atom, a fluorine atom, an alkyl group or an alkoxy group having 1 to 5 carbon atoms, or a fluorine-substituted hydrocarbon. In the general formula (2), at least one of R _{1 to} R ₄ and R _{1 to} R _{8 in} the general formula (3) is a fluorine atom or a fluorine-substituted group. It is a hydrocarbon group. ]]

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