JP2011209524A - Laminate and display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate which is capable of suppressing the maximum amount of deflection generated therein due to a change in temperature or relative humidity of an atmosphere wherein the laminate is used, and to provide a display device which is assembled using the laminate as a substrate and is free from display defects and component mounting failures.SOLUTION: In the laminate having a plurality of layers, one arbitrary layer constituting the laminate has a thermal expansion coefficient of 15 ppm/K or less and a humidity expansion coefficient of 70 ppm/%RH, and a difference between a thermal expansion coefficient of at least one of layers sharing interfaces with the one arbitrary layer and the thermal expansion coefficient of the one arbitrary layer is 20 ppm/K or less, and a difference between a humidity expansion coefficient of at least the one of the layers sharing the interfaces with the one arbitrary layer and the humidity expansion coefficient of the one arbitrary layer is 20 ppm/%RH or less.

Description

  The present invention relates to a laminate having a plurality of layers, and more particularly to a laminate used for a display device.

  In recent years, there has been an increasing demand for multifunctional display devices or electronic devices. In connection with that, the use of the laminated board comprised by laminating | stacking a some material is increasing. This is because the laminated plate is composed of a plurality of materials, so that characteristics that cannot be obtained with a single material can be obtained.

  On the other hand, there is an increasing demand for characteristics that are suitable for the conditions of the atmosphere in which the laminated board is used, especially dimensional stability and environmental resistance against changes in temperature and relative humidity. . In particular, with regard to dimensional stability, it is required to satisfy stricter conditions than ever as the pursuit for further high definition and thinning of the display device and the electronic device progresses.

  By the way, since the physical properties of each of the multiple layers constituting the laminated plate are not necessarily the same, the deformation behavior of each layer alone is not necessarily the same with respect to environmental changes such as temperature changes and relative humidity changes. Must not. In this way, when the laminated plate is composed of a plurality of layers, the deformation behavior of each layer is different for each layer, in order to maintain the configuration as a laminated plate without causing slippage or slipping at the interface between the layers, Deflection occurs in the laminate.

  The deflection generated in such a laminated plate is one of the causes that cause various problems when the laminated plate is used. For example, when the above-described deflection occurs in the laminated plate constituting the display device, there is a high possibility of causing problems such as uneven display of images or defective mounting of display drive components.

  Various countermeasures have been taken so far for the purpose of suppressing the deflection generated in the laminated board as described above. For example, a means has been devised that is excellent in reflow resistance and can reduce warpage by defining the thermal expansion coefficient of an insulating film layer constituting a laminate (Patent Document 1).

  Furthermore, by defining not only the range that can be taken for the linear thermal expansion coefficient of each layer that constitutes the laminate, but also the range that can be taken for the humidity expansion coefficient, it is possible to warp at the time of temperature change or humidity change of the laminate. Means that can prevent this have been devised (Patent Document 2).

  However, in Patent Document 1, although the value of the thermal expansion coefficient with respect to the temperature change is defined for the characteristics of the layers constituting the laminate, the physical property value considered to be related to the change in relative humidity is saturated. It only defines the hygroscopic expansion rate (%), that is, the water absorption rate (%). This only indicates the static water absorption capacity of the layer, and it is difficult to say that the dynamic influence due to the change in relative humidity is taken into consideration.

  The specified ranges of the thermal expansion coefficient and the humidity expansion coefficient disclosed in Patent Document 2 are limited to applications suitable for the optical information recording medium and the manufacturing method thereof, and the temperature of the atmosphere in which the display device or the like is used. It is hard to say that the conditions correspond to changes and relative humidity changes.

JP 2004-031931 A JP 2009-277346 A

  In view of the problems of the prior art as described above, the present invention provides a laminate that can ensure dimensional stability and suppress deflection even when the temperature or relative humidity of the atmosphere in which the laminate is used changes. Another object of the present invention is to provide a display device in which display defects such as display unevenness and component mounting defects such as display drive components do not occur in a display device assembled using the laminate as a substrate. It is what.

  In order to achieve the above object, the laminate of the present invention is a laminate having a plurality of layers, and is 20 ° C. above the glass transition temperature of any one of the plurality of layers constituting the laminate. The thermal expansion coefficient at a low temperature or lower is 15 ppm / K or lower, and the humidity expansion coefficient of the arbitrary one layer is 70 ppm /% RH or lower, and shares an interface with the arbitrary one layer. A coefficient of thermal expansion below 20 ° C. below the glass transition temperature of at least one of the layers, and a coefficient of thermal expansion below 20 ° C. below the glass transition temperature of any one of the layers, The difference between the humidity expansion coefficient of at least one of the layers sharing the interface with the arbitrary one layer and the humidity expansion coefficient of the arbitrary one layer is 20 ppm. /% RH or less To.

  In addition, a display device can be configured using the laminate of the present invention as a substrate.

  According to the laminate of the present invention, even if the temperature or relative humidity of the atmosphere in which the laminate is used changes, any one layer constituting the laminate and the any one layer and the interface Since the strain generated between at least one of the layers sharing the same can be reduced, the maximum amount of deflection generated in the laminated plate can be suppressed, and the warpage against temperature change and humidity change can be reduced. Furthermore, the display device assembled by using the laminate as a substrate can suppress the maximum deflection of the laminate even if the temperature or relative humidity of the atmosphere in which the display device is used changes. It is possible to suppress the occurrence of display defects such as image display unevenness due to the maximum deflection amount of the laminated plate, and component mounting defects of display drive components.

It is sectional drawing which shows an example of the laminated board which has multiple layers. It is sectional drawing which shows an example of the laminated board which the bending generate | occur | produced by the temperature change and the change of relative humidity. It is a figure which shows the cross section of the arbitrary 1 layer of the several layers which comprise a laminated board, and the at least 1 layer of the layers which share an interface with the said arbitrary 1 layer.

The present invention will be described in detail below.
An example of a laminated board having a plurality of layers is shown in FIG. Here, the coordinates are set so that the y-axis is directed downward from the upper end of the uppermost layer. In addition, the plurality of layers constituting the laminated plate have the uppermost layer as the first layer, the second layer,. . . , I th layer, (i + 1) th layer,. . . , And the nth layer.

  When the temperature or relative humidity of the atmosphere in which the laminated board having a plurality of layers is used changes, deflection occurs as shown in FIG. In this case, in the laminated plate, there is a relationship represented by the following formula (1), formula (2), formula (3), and formula (4).

Here, the symbols in the above equations (1), (2), (3), and (4) will be described. ρ _i represents the radius of curvature of the i-th layer, M _i represents the bending moment around the neutral plane of the i-th layer, E _i represents the longitudinal elastic modulus of the i-th layer, and I _i Indicates the second moment of section around the neutral plane of the i-th layer, α _i indicates the thermal expansion coefficient of the i-th layer, ΔT indicates the temperature change of the atmosphere in which the laminate is used, and ζ _i represents the humidity expansion coefficient of the i-th layer, ΔH represents the change in relative humidity of the atmosphere in which the laminate is used, P _i represents the axial force acting on the i-th layer, and A _i represents the i-th layer. i represents the cross-sectional area of the i-th layer, h _i represents the thickness of the i-th layer, α _{i + 1} represents the thermal expansion coefficient of the (i + 1) -th layer, and ζ _{i + 1} represents the (i + 1) -th layer. shows the humidity expansion coefficient of _{layer, P i + 1} represents the axial force acting on the (i + 1) th _{layer, a i + 1} is the cross section of the (i + 1) th layer Are _{shown, E i + 1} represents the longitudinal elastic coefficient of the (i + 1) th _{layer, h i + 1} denotes the thickness of the (i + 1) th layer, the [rho _{i + 1} the curvature radius of the (i + 1) th layer Show. Furthermore, y represents the distance from the upper surface of the uppermost layer of the laminate to the neutral plane of the laminate.

  Next, the contents of the expressions (1), (2), (3), and (4) will be described. Equation (1) represents the relationship between the radius of curvature related to the deflection of the i-th layer and the bending moment around the neutral plane of the i-th layer. Equation (2) is derived from the strain generated due to the i-th layer and the (i + 1) -th layer at the interface shared by the i-th layer and the (i + 1) -th layer. This means that the generated strain is equal. Formula (3) represents that the axial force acting on each of the plurality of layers constituting the laminate is balanced. Equation (4) represents that the bending moments around the neutral plane acting on each of the plurality of layers constituting the laminate are balanced.

  The radius of curvature ρ of the neutral plane can be obtained from the above equations (1), (2), (3), and (4). The maximum deflection amount can be calculated by substituting the radius of curvature of the neutral plane into the following equation (5).

The meanings of the symbols in the formula (5) are as follows. V _max indicates the maximum amount of deflection generated in the laminate, and L indicates the length of the laminate.

  By performing the above calculation, when the temperature or relative humidity of the atmosphere in which the laminated board having a plurality of layers is changed, the maximum deflection amount generated in the laminated j board can be obtained.

  If it is considered that the radius of curvature of the laminated plate is sufficiently larger than the thickness of the laminated plate, the radius of curvature of each of the plurality of layers of the laminated plate can be expressed as the following equation (6).

  That is, it can be considered that the radius of curvature of each of the plurality of layers of the laminate is equal to the radius of curvature ρ of the neutral plane of the laminate. A method for obtaining the curvature radius ρ of the laminate using this relationship will be specifically described.

  Now, as shown in FIG. 3, attention is focused on the i-th layer and the (i + 1) -th layer among the plurality of layers of the laminate. The i-th layer and the (i + 1) -th layer share a common interface. From equation (6), equations (1) and (2) can be expressed as follows.

  Further, from the relationship of Expression (3), the following Expression (9) is established.

  On the other hand, the balance of the bending moment around the neutral plane expressed by the equation (4) is expressed by the equation (6) in the case of the i-th layer and the (i + 1) -th layer shown in FIG. Considering this relationship, it can be expressed as the following equation (10), considering the balance of the bending moment at the interface shared by the i-th layer and the (i + 1) -th layer.

  The equation for obtaining the radius of curvature ρ of the laminate by the above equations (7), (8), (9), and (10) is represented by the following equation (11).

If the thickness h _i of the i-th layer is equal to the thickness h _{i + 1 of} the (i + 1) -th layer and both are h, then the above equation (11) is expressed by the following equation: It can be simplified as in (12).

From the above equation (5), in order to reduce the maximum deflection amount V _max of the laminate, the material of each layer of the laminate may be selected so that the radius of curvature ρ of the laminate is increased. . Specifically, it is only necessary that the parts represented by α _i , α _{i + 1} , ΔT, ζ _i , ζ _{i + 1} , and ΔH in the formula (12) are as close to 0 as possible. That is, it is as represented by the following formula (13).

  As a material of each layer of the multilayer board, high heat-resistant polyimide resin, polyester resin, polycarbonate resin, aramid resin, polymethyl methacrylate resin, polyether sulfide resin, polyphenylene sulfide resin, polyamide resin, polyethylene naphthalate resin, Examples include polyetherimide resins, modified polyphenyl ether resins, polyphenylene sulfide resins, polyether sulfone resins, epoxy resins, transparent polyimide resins, and liquid crystal polymer resins. In addition, a glass plate, copper foil, etc. can also be used.

  A material having an adhesive function may be obtained by giving thermal reactivity or optical reactivity to the materials mentioned above. Furthermore, it is good also as a material which combined the material mentioned above, inorganic fiber, such as glass fiber, and organic fiber as a reinforcing material.

  By the way, a laminated board having a plurality of layers often includes a layer having a function as a core material for ensuring the strength of the whole laminated board, and the temperature or relative humidity of the atmosphere in which the laminated board is used changes. In such a case, the material is often selected so that the amount of deformation of the layer itself serving as the core material is reduced. The layer itself serving as the core material desirably has a thermal expansion coefficient of 15 ppm / K or less so that the amount of deformation with respect to temperature change is small. Further, it is desirable and preferable that the layer itself serving as the core material has a humidity expansion coefficient of 70 ppm /% RH or less so that a deformation amount with respect to a change in relative humidity becomes small.

  The reason why the measured value at a temperature 20 ° C. or lower than the glass transition temperature is employed as the thermal expansion coefficient is as follows. That is, the temperature dependence of the thermal expansion coefficient is large in the temperature range where the difference from the glass transition temperature is 10 ° C. or less, and the thermal expansion coefficient changes rapidly only by a temperature change of 1 ° C. near the glass transition temperature. For this reason, it is difficult to compare the thermal expansion coefficient for each material as a physical property value.

  Further, a desirable thermal expansion coefficient of the layer material that serves as a core material of the laminate is preferably 15 ppm / K or less. On the other hand, the layer material that acts as the core material of the laminate is preferable. The desired humidity expansion coefficient is 70 ppm / K or less, and the thermal expansion coefficient and the humidity expansion coefficient are in different ranges because the change rate of the temperature change of the atmosphere and the change of relative humidity are different. is there. In general, the rate of change in relative humidity is slower than the rate of change in temperature, and the slower the change, the smaller the external load on the material exposed to the atmosphere. Conversely, the change in temperature is faster than the change in relative humidity, and the external load on the material exposed to the atmosphere must be greatly estimated. As a result, the condition range for the coefficient of thermal expansion is set low. There is a need to.

  An arbitrary layer of the laminated plate including a layer that serves as a core material of the laminated plate as described above, and a layer sharing an interface with the arbitrary one layer are represented by the above formula ( 13) In order to realize the relationship shown in FIG. 13, a thermal expansion coefficient at a temperature not higher than 20 ° C. lower than the glass transition point temperature of any one of the plurality of layers constituting the laminate having a plurality of layers, The difference between the thermal expansion coefficient of at least one of the layers sharing an interface with any one of the layers at a temperature lower than or equal to 20 ° C. below the glass transition temperature is better. The smaller the difference between the humidity expansion coefficient of one layer and the humidity expansion coefficient of at least one of the layers sharing the interface with the arbitrary one layer, the better.

  On the other hand, the difference in thermal expansion coefficient between the arbitrary one layer and the layer sharing the interface with the arbitrary one layer is 20 ppm / K or less, and further, the arbitrary one layer and the arbitrary one layer The difference between the coefficient of humidity expansion of the layer sharing the interface with the layer is 20 ppm /% RH or less. Within these ranges, when the laminate is used for a display material, an electronic device, or the like, with respect to a change in temperature or relative humidity of an atmosphere in which the display device or the electronic device is used, the It can be used without degrading the performance of a display device or an electronic device.

However, the possible range of the thermal expansion coefficient, the possible range of the humidity expansion coefficient in the formula (11), the thickness h _i of the i-th layer, the thickness of the (i + 1) th layer In many cases, h _{i + 1} is assumed to be on the order of 1 μm or more. If the thickness of the i-th layer _{h i} or, if the (i + 1) the thickness of the second layer _{h i + 1} is equal to or less than the order of a few 10 nm, the formula (11), and the formula (5 Therefore, in order to reduce the maximum deflection, not only the range that the thermal expansion coefficient can take and the range that the humidity expansion coefficient can take, but also the conditions for the elastic coefficient must be considered. This is outside the scope of the present invention.

  A display device can be formed using the laminate having a plurality of layers. Specifically, liquid crystal display (Liquid Crystal Display, hereinafter abbreviated as LCD), plasma display (Plasma Display Panel, hereinafter abbreviated as PDP), organic EL display (Organic Electroluminescence Display, hereinafter abbreviated as OLED), field emission There is a type display device (Field Emission Display, hereinafter abbreviated as FED). Conventionally, a glass substrate has been mainly used as a substrate of these display devices, but recently, a laminated plate made of glass and plastic is often used.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Prior to the description of the examples, a method for measuring physical property values necessary for carrying out the present invention will be described.

  The glass transition temperature is measured by measuring the dynamic viscoelasticity of the material, and when the result is plotted in a graph of the relationship between temperature and loss tangent (tan δ), the temperature at the peak apex (peak top temperature) is the glass transition temperature. Let it be temperature. In practice, the peak top temperature is automatically detected by the measuring device. That is, using a forced vibration non-resonance type viscoelasticity measuring device (Orientec Co., Ltd., trade name: Leo Vibron), measurement conditions: excitation frequency 11 Hz, static tension 3.0 gf, sample size 0.5 mm (width) It is obtained by raising the temperature to 400 ° C. at a temperature rising rate of 10 ° C./min from a room temperature and humidity environment at a length of 30 mm (long) and determining the relationship between the temperature and loss tangent.

  The thermal expansion coefficient is a tensile measurement using Thermo Mechanical Analyzer (manufactured by Seiko Instruments Inc.), and is 20 ° C. lower than the glass transition temperature of the measurement sample from 50 ° C. according to the average thermal expansion coefficient calculation method shown in JIS K7197. The average coefficient of thermal expansion at temperature was calculated. That is, the film-like sample was heated to a temperature 20 ° C. lower than the glass transition temperature, cooled at 5 ° C./min, and averaged from a temperature 20 ° C. to 50 ° C. lower than the glass transition temperature of the measurement sample. It is obtained by measuring the thermal expansion coefficient.

The humidity expansion coefficient is a resin film having a size of 1.5 cm × 2.5 mm at 25 ° C., and the length in the major axis direction (L25 and L90) at 25% and 90% relative humidity (RH) is measured. From the obtained measured value difference L (cm) = L90−L25, the following equation is used.
L (cm) × 1 / 1.5 (cm) × 1 / (90-25) (% RH)
Specific measurement conditions were a humidity-controlled Thermo Mechanical Analyzer (manufactured by SII Nanotechnology Co., Ltd.) and controlled the measurement temperature at 25 ° C., and the major axis direction at 25% and 90% relative humidity of the resin film of the sample. The dimensional change per 1 cm is measured as a humidity expansion coefficient.

  The maximum amount of deflection generated in the laminate was measured by a three-dimensional dimension measuring machine (Nikon Corporation CNC image measurement system NEXIV). Specifically, the value of the Z coordinate is obtained by focusing the microscope on the apex of the sample with a size of 60 mm × 80 mm, and the maximum deflection from the reference plane is determined with the plane passing through the lowest point as the reference plane. The amount.

  A constant temperature and humidity chamber (Yamato Scientific Co., Ltd., IG420) was used in order to set the temperature change and the relative humidity change of the atmosphere using the laminate to desired values. The initial conditions for temperature and relative humidity are set, and the temperature and relative humidity that are desired to be reached from the initial conditions are set. Furthermore, the temperature change speed is set for the temperature. Since the relative humidity is controlled following the temperature change, the rate of change of the relative humidity is not determined.

Example 1
Aramid resin film (Mikutron manufactured by Toray Industries, Inc., thermal expansion coefficient 13 ppm / K, humidity expansion coefficient 15 ppm /% RH, thickness 100 μm) and polyamideimide resin film (type C, manufactured by Toyobo Co., Ltd., thermal expansion coefficient 22 ppm / K) And a humidity expansion coefficient of 10 ppm /% RH and a thickness of 100 μm) via a thermosetting adhesive A (thermal expansion coefficient of 15 ppm / K, humidity expansion coefficient of 20 ppm /% RH, cured product thickness of 40 μm). A laminate [1] was obtained. The thermosetting adhesive A comprises 175 parts by weight of bisphenol A type epoxy resin (epoxy equivalent: 175), 110 parts by weight of bisphenol A (hydroxyl equivalent: 110), and 1.77 parts by weight of sodium hydroxide in N, N-dimethyl. It is a linear epoxy polymer solution obtained by dissolving in 547.9 parts by mass of formamide, maintaining the temperature at 120 ° C. with an oil bath while stirring, and then reacting for 3 hours. The aramid resin film, thermosetting adhesive A, and polyamide-imide resin film were heat-pressed at 200 ° C. and 3 MPa for 30 minutes with a vacuum press to obtain a laminate [1]. When the leaving environment of the obtained laminated board [1] was changed from the state of 25 ° C. and 45% RH to the state of 60 ° C. and 90% RH over 5 minutes, the maximum deflection amount of the laminated board [1] was obtained. Was 95 μm.

(Example 2)
Aramid resin film (Mikutron manufactured by Toray Industries, Inc., thermal expansion coefficient 13 ppm / K, humidity expansion coefficient 15 ppm /% RH, thickness 100 μm) and polyamideimide resin film (type C, manufactured by Toyobo Co., Ltd., thermal expansion coefficient 22 ppm / K) And a humidity expansion coefficient of 10 ppm /% RH and a thickness of 100 μm) via a photocurable adhesive A (thermal expansion coefficient of 16 ppm / K, humidity expansion coefficient of 18 ppm /% RH, cured product thickness of 50 μm). A laminate [2] was obtained. The photocurable adhesive A comprises 45 parts by mass of polyamic acid, a photopolymerizable compound TMCH-5 (a photopolymerizable compound having a urethane bond, an alicyclic hydrocarbon skeleton, and an ethylenically unsaturated group in the molecule, 35 parts by mass of Hitachi Chemical Co., Ltd.) and 7 of photopolymerization initiator Irgacure 651 (I-651, 2,2-dimethoxy-1,2-diphenylethane-1-one, manufactured by Ciba Specialty Chemicals) 13 parts by mass of 13 parts by mass of a cross-linking agent YH-434 (tetrafunctional amine type epoxy resin, manufactured by Toto Kasei Co., Ltd.) on a light release film (Therapy MD, manufactured by Toray Film Processing Co., Ltd.) 2,000 r. p. m. It is obtained by peeling off from the light release film after heating for 4 minutes on a hot plate at 100 ° C. The aramid resin film, photocurable adhesive A, and polyamideimide resin film were pressed by a press machine at 70 ° C. and 0.5 MPa for 3 minutes, and then UV irradiation exposure machine (center wavelength 365 nm). ), The laminate [2] was obtained by exposing at an illuminance of 600 mJ / min. When the leaving environment of the obtained laminate [2] was changed from the state of 25 ° C. and 45% RH to the state of 60 ° C. and 90% RH over 5 minutes, the maximum deflection amount of the laminate [2] was obtained. Was 75 μm.

(Example 3)
The laminate [1] obtained in Example 1 and the laminate [2] obtained in Example 2 were used as the laminate [3] configured with the thermosetting adhesive A interposed therebetween. The laminated board [1], the thermosetting adhesive A, and the laminated board [2] are heated and pressed at 200 ° C. and 3 MPa for 30 minutes by a press machine to obtain the laminated board [3]. It was. When the leaving environment of the obtained laminate [3] was changed from 25 ° C. and 45% RH to 60 ° C. and 90% RH over 5 minutes, the maximum deflection in the laminate was 60 μm. Met.

Example 4
The laminate [1] obtained in Example 1 and the laminate [2] obtained in Example 2 are referred to as a laminate [4] configured with the photo-curable adhesive A interposed therebetween. The laminate [1], the photocurable adhesive A, and the laminate [2] are pressed with a press machine at 70 ° C. and 0.5 MPa for 3 minutes, and then UV irradiated with a UV irradiation exposure machine. Laminate [4] was obtained by exposing with an illuminance of 600 mJ / min with an exposure machine (center wavelength: 365 nm). When the leaving environment of the obtained laminate [4] was changed from the state of 25 ° C. and 45% RH to the state of 60 ° C. and 90% RH over 5 minutes, the maximum deflection amount of the laminate [4] was obtained. Was 55 μm.

(Example 5)
Polyether sulfone resin film (Sumika Excel, manufactured by Sumitomo Chemical Co., Ltd., thermal expansion coefficient 5.7 ppm / K, humidity expansion coefficient 10 ppm /% RH, thickness 100 μm) and glass plate (D263, manufactured by Matsunami Glass Industrial Co., Ltd.) And a thermal expansion coefficient of 7.2 ppm / K, a humidity expansion coefficient of 0.5 ppm /% RH or less, and a thickness of 100 μm) were used as a laminate [5] composed of the photocurable adhesive A. The polyether sulfone resin film, the photocurable adhesive A, and the glass plate are pressed at 70 ° C. and 0.5 MPa for 3 minutes, and then exposed at an illuminance of 600 mJ / min by a UV irradiation exposure machine (center wavelength 365 nm). Thus, a laminate [5] was obtained. When the leaving environment of the obtained laminate [5] was changed from 25 ° C. and 45% RH to 60 ° C. and 90% RH over 5 minutes, the maximum deflection of the laminate [5] was It was 50 μm.

(Example 6)
A TFT (Thin Film Transistor) is formed on the laminate [5] of Example 5, an alignment film (Rixon Aligner, manufactured by Chisso Corporation) is formed on the TFT, and a seal is formed on the alignment film. An adhesive (thermosetting sealant 3025B, manufactured by ThreeBond Co., Ltd.) is formed in a frame shape, a liquid crystal is arranged in an inner region where the sealant is arranged in a frame shape, and a spacer (micrometer) is formed in the liquid crystal. Pearl EX, manufactured by Sekisui Chemical Co., Ltd.), the liquid crystal is sealed with a color filter substrate, and the TFT driving component is further bonded to the laminated plate [5 via an anisotropic conductive adhesive film. ] Was mounted on the electrode to form a liquid crystal display device. When the liquid crystal display device displayed an image in an atmosphere of 25 ° C. and 45% RH, a good image could be obtained. Further, even when the standing environment of the liquid crystal display device was changed from 25 ° C. and 45% RH to 60 ° C. and 90% RH over 5 minutes, the image display state was good.

(Comparative example)
Polyamideimide resin film (type A, manufactured by Toyobo Co., Ltd., thermal expansion coefficient 50 ppm / K, humidity expansion coefficient 45 ppm /% RH, thickness 100 μm) and high heat-resistant transparent polyimide resin film (L-, manufactured by Mitsubishi Gas Chemical Co., Ltd.) 1000, a thermal expansion coefficient of 54 ppm / K, a humidity expansion coefficient of 50 ppm /% RH or less, and a thickness of 100 μm) were used as a laminate [6] configured with the photocurable adhesive A interposed therebetween. The polyamideimide resin film, photocurable adhesive A, and high heat-resistant transparent polyimide resin film were pressed at 70 ° C. and 0.5 MPa for 3 minutes, and then irradiated with a UV irradiation exposure machine (center wavelength: 365 nm) with an illuminance of 600 mJ / Laminate [6] was obtained by exposing in minutes. When the leaving environment of the obtained laminate [6] was changed from the state of 25 ° C. and 45% RH to the state of 60 ° C. and 90% RH over 5 minutes, the maximum deflection amount of the laminate [6] was obtained. Was 2626 μm.

  The above Examples and Comparative Examples are summarized in Table 1.

  The arbitrary one having a thermal expansion coefficient of 15 ppm / K or less and a humidity expansion coefficient of 70 ppm /% RH or less at a temperature 20 ° C. or less lower than the glass transition temperature of any one of the plurality of layers. The coefficient of thermal expansion below 20 ° C. below the glass transition temperature of at least one of the layers sharing an interface with one layer and the temperature 20 ° C. below the glass transition temperature of any one of the layers The difference between the thermal expansion coefficient in the following is 20 ppm / K or less, and the humidity expansion coefficient of at least one of the layers sharing the interface with the arbitrary one layer and the humidity of the arbitrary one layer In Examples 1 to 6, in which the difference from the expansion coefficient is 20 ppm /% RH or less, the amount of deflection is small. On the other hand, the coefficient of thermal expansion of any one layer exceeds 15 ppm / K (50, 16, 54 ppm / K), and the difference between the coefficient of thermal expansion between the arbitrary layer and the layer sharing the interface is 20 ppm / K Even if it exceeds K (34,38 ppm / K) and the humidity expansion coefficient is 70 ppm /% RH or less, the humidity expansion coefficient of at least one of the layers sharing the interface with any one layer and any The difference between the humidity expansion coefficient of one layer exceeds 20 ppm /% RH (27,32 ppm /% RH) and the amount of deflection is extremely large.

DESCRIPTION OF SYMBOLS 1 ... Neutral surface 2 ... 1st layer 3 ... 2nd layer 4a ... i-th layer 4b ... (i + 1) th layer 5 ... 1st layer nth layer

Claims (2)

A laminate having a plurality of layers, wherein a coefficient of thermal expansion at a temperature 20 ° C. or less lower than the glass transition temperature of any one of the plurality of layers constituting the laminate is 15 ppm / K or less. And the humidity expansion coefficient of the arbitrary layer is 70 ppm /% RH or less, and is higher than the glass transition temperature of at least one of the layers sharing the interface with the arbitrary layer. The difference between the coefficient of thermal expansion below 20 ° C. and the coefficient of thermal expansion below 20 ° C. below the glass transition temperature of the one arbitrary layer is 20 ppm / K or less, The laminated board characterized by the difference between the humidity expansion coefficient of at least one of the layers sharing an interface with one layer and the humidity expansion coefficient of the arbitrary one layer being 20 ppm /% RH or less. A display device comprising the laminate according to claim 1 as a substrate.

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