111111
`
`1111111111111111111111111111111111111111111111111111111111111111111111111111
`US 20100178834Al
`
`(19) United States
`c12) Patent Application Publication
`Toyoda et al.
`
`(10) Pub. No.: US 2010/0178834 A1
`Jul. 15, 2010
`(43) Pub. Date:
`
`(54) METHOD FOR PRODUCING DISPLAY
`DEVICE
`
`(75)
`
`Inventors:
`
`Tomoyuki Toyoda, Kanuma-shi
`(JP); Tsutomu Dejima,
`Utsunomiya-shi (JP); Yoshihisa
`Shinya, Utsunomiya-shi (JP);
`Yusuke Kamata, Utsunomiya-shi
`(JP)
`
`Correspondence Address:
`OLIFF & BERRIDGE, PLC
`P.O. BOX 320850
`ALEXANDRIA, VA 22320-4850 (US)
`
`(73) Assignee:
`
`SONY CHEMICAL &
`INFORMATION DEVICE
`CORPORATION, TOKYO (JP)
`
`(21) Appl. No.:
`
`12/656,088
`
`(22) Filed:
`
`Jan.15,2010
`
`Related U.S. Application Data
`
`(63) Continuation of application No. PCT/JP2008/062855,
`filed on Jul. 16, 2008.
`
`(30)
`
`Foreign Application Priority Data
`
`(JP) ................................. 2007-186360
`Jul. 17, 2007
`(JP) ................................. 2008-005027
`Jan. 11, 2008
`(JP) ................................. 2008-105109
`Apr. 14, 2008
`Publication Classification
`
`(51)
`
`Int. Cl.
`HOJJ 9120
`(2006.01)
`(52) U.S. Cl. .......................................................... 445/24
`ABSTRACT
`(57)
`
`A method for producing a display device in which a repair
`operation can be carried out easily and reliably without dam(cid:173)
`age to a bonding portion caused by a cured resin. The method
`comprises: (a) coating a resin composition on at least one of
`the display part and the protective part, (b) closely adhering
`the display part and the protective part via the resin compo(cid:173)
`sition interposed therebetween, and (c) arranging the cured
`resin layer between the display part and the protective part by
`curing the resin composition by irradiating UV rays exter(cid:173)
`nally side of protective part. The method further comprises,
`depending on the presence of defects: (d) separating the dis(cid:173)
`play part and the protective part by being in contact with a
`wire having a smaller diameter than a thickness of the cured
`resin layer to a side face of the cured resin layer where the
`protective part and the display part are bonded and moving the
`wire through the cured resin layer, (e) peeling off and remov(cid:173)
`ing the cured resin adhered to the separated display part and
`the protective part by a removing solution which contains an
`organic solvent, and (f) repeating steps (a) to (c).
`
`Start
`
`1 of 13
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`FITBIT EXHIBIT 1008
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`

`

`Patent Application Publication
`
`Jul. 15, 2010 Sheet 1 of 6
`
`US 2010/0178834 A1
`
`Fig. 1
`
`S1
`
`Dropping resin composition
`
`S2
`
`Filling resin solution between
`Display part and protective part
`S3
`
`Cu!:!!_lg resin composition
`by UV Ray irradiation
`
`Check for presence of air
`bubbles or the like
`
`S4
`
`NO
`
`S6
`
`Cutting display part and
`protective part to separate
`S7
`
`Wiping away resin by
`organic solvent
`
`Examination of wiped surface
`
`NO
`
`YES
`
`End
`
`2 of 13
`
`

`

`Patent Application Publication
`
`Jul. 15, 2010 Sheet 2 of 6
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`US 2010/0178834 A1
`
`4
`
`Fig. 2 (a)
`
`Fig. 2 (b)
`
`Fig. 2 (c)
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`2
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`3
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`4
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`2
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`3
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`5
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`2
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`3 of 13
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`Patent Application Publication
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`Jul. 15, 2010 Sheet 3 of 6
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`US 2010/0178834 A1
`
`Fig. 3 (a)
`
`Fig. 3 (b)
`
`Fig. 3 (c) - -:
`
`4 of 13
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`

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`Patent Application Publication
`
`Jul. 15, 2010 Sheet 4 of 6
`
`US 2010/0178834 A1
`
`Fig. 4
`
`....--......... 1
`
`2(3)
`
`.. --~ 5
`.·
`
`Fig. 5
`
`~----------------~....--........1
`
`2(3)
`
`1
`
`5 of 13
`
`

`

`Patent Application Publication
`
`Jul. 15, 2010 Sheet 5 of 6
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`US 2010/0178834 A1
`
`;::.xrt {LCl)
`
`! '~
`! 1
`.//~:~. --~~~z~:~z>>~
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`··._···.··,,_··:·,··, ...... · .•. ·.·_··.· .. ,~_.:_~_-_: __ ,·_:._:,::_ ... _ .. _·_: .• :_.~:_._:_._:._~_, __ ::_:._ .• ·,_ .• :· .. · .. · .. _' .. : .. :_.~::._:_._:_._:_._.,_._:._:· ... :.··· ..•. ::_.::;
`
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`···••.•.
`L·:·: .......... :.i.. ........... :;; ........... ::::: ...... :~;. .... ::·~ ... ~:-~ ..... :·;-..... ::~h--·-·-·-·:::.. ....... ·..,...· ··;;...........···~~~,
`~ ~
`~ ..... J
`
`i
`
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`
`Fi;:~ 6 (b)
`
`6 of 13
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`

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`Patent Application Publication
`
`Jul. 15, 2010 Sheet 6 of 6
`
`US 2010/0178834 A1
`
`Fig. 7
`
`105
`
`104
`
`103
`104
`
`102
`
`7 of 13
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`

`

`US 2010/0178834 AI
`
`Jul. 15, 2010
`
`1
`
`METHOD FOR PRODUCING DISPLAY
`DEVICE
`
`[0001] This application is a continuation of International
`Application No. PCT/JP2008/062855 filed Jul. 16, 2008,
`which claims priority to Japanese Patent Document No.
`2007-186360, filed on Jul. 17, 2007, Japanese Patent Docu(cid:173)
`ment No. 2008-005027, filed on Jan. 11, 2008, and Japanese
`Patent Document No. 2008-105109, filed on Apr. 14, 2008.
`The entire disclosures of the above-mentioned applications
`are incorporated herein by reference in their entireties.
`
`BACKGROUND
`
`[0002] The present disclosure is generally directed to a
`display device, such as, for example, a liquid crystal display
`device (LCD) used in a cellular phone. In particular, the
`present disclosure is directed to a method for producing a
`display device provided with a transparent protective part on
`a display part.
`[0003] FIG. 7 illustrates a conventional type of display
`device known in the art. As shown in FIG. 7, a liquid crystal
`display device 101 is provided with a transparent protective
`part 103 formed from, for example, glass or plastic, on a
`liquid crystal display panel102. In this conventional device,
`in order to protect the surface of the liquid crystal display
`panel 102 and a polarizing plate (not shown), a gap 105
`between the liquid crystal display panel102 and the protec(cid:173)
`tive part 103 is formed by spacers 104 arranged between the
`liquid crystal display panel102 and the protective part 103.
`[0004] However, the gap 105 between the liquid crystal
`display panel 102 and the protective part 103 scatters light,
`resulting in a decrease in contrast and luminance. The pres(cid:173)
`ence of the gap 105 also makes it more difficult to produce a
`thinner panel.
`[0005]
`In view of these difficulties, it has been proposed to
`fill the gap between the liquid crystal display panel and the
`protective part with a resin (for example, see Japanese Patent
`Publication No. 2005-55641).
`[0006] However, if foreign substances or air bubbles
`become trapped in the resin that fills the gap between the
`liquid crystal display panel and the protective part, it becomes
`necessary to conduct a repair operation by peeling apart the
`display panel and the protective part.
`[0007] However, when the display panel and the protective
`part are peeled apart, there is a risk of causing damage, such
`as scratching and cracking the display panel and the protec(cid:173)
`tive part.
`[0008] Furthermore, completely removing a cured resin
`adhered to the display panel and the protective part by a
`solvent is very difficult.
`[0009] While there are some solvents which have high solu(cid:173)
`bility against this type of cured resin, there are drawbacks
`with respect to safety. Moreover, in order to completely
`remove the solvent itself, a separate washing step is required.
`
`[0011] Embodiments are provided in order to achieve the
`above object, and include a method for producing a display
`device, the display device comprising a display part for dis(cid:173)
`playing an image with a light-transmitting protective part
`provided on the display part, and a light-transmitting cured
`resin layer arranged between the display part and the protec(cid:173)
`tive part. The method for producing a display device accord(cid:173)
`ing to the present invention includes the steps (a) to (c), and,
`depending on the presence of defects in the display device, the
`following additional steps (d) to (f) are performed:
`[0012]
`(a) coating a resin composition, the resin composi(cid:173)
`tion comprising a raw material of the cured resin, on at least
`one of the display part and the protective part,
`[0013]
`(b) closely adhering the display part and the protec(cid:173)
`tive part with the resin composition interposed therebetween,
`and
`[0014]
`(c) arranging the cured resin layer between the dis(cid:173)
`play part and the protective part by curing the resin compo(cid:173)
`sition by irradiating UV rays on an external side of the pro(cid:173)
`tective part; and
`[0015]
`(d) separating the display part and the protective part
`from contact with each other by applying a wire having a
`smaller diameter than a thickness of the cured resin layer to a
`side face of the cured resin layer where the protective part and
`the display part are bonded together, and moving the wire
`through the cured resin layer,
`[0016]
`(e) peeling off and removing the cured resin adhered
`to the separated display part and the protective part by using
`a solution which contains an organic solvent, and
`(f) repeating the steps (a) to (c).
`[0017]
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0018] FIG. 1 is a flow diagram illustrating an example of a
`method for producing a display device according to embodi(cid:173)
`ments.
`[0019] FIGS. 2(a) to (c) are cross-sectional views sche(cid:173)
`matically illustrating the method for producing a display
`device according to embodiments.
`[0020] FIGS. 3(a) to (c) are cross-sectional views sche(cid:173)
`matically illustrating a method for producing the display
`device according to the present disclosure.
`[0021] FIG. 4 is an explanatory diagram illustrating an
`example of a method for cutting a cured resin layer according
`to embodiments.
`[0022] FIG. 5 is an explanatory diagram illustrating another
`example of a method for cutting a cured resin layer according
`to embodiments.
`[0023] FIGS. 6(a) to (c) are explanatory diagrams sche(cid:173)
`matically illustrating a method for wiping away a cured resin
`by an organic solvent.
`[0024] FIG. 7 is cross-sectional view illustrating a configu(cid:173)
`ration of a conventional display device.
`
`DETAILED DESCRIPTION OF THE
`DISCLOSURE
`
`SUMMARY
`
`[001 0] The present disclosure was made in consideration of
`these needs and other needs present in the conventional art.
`Accordingly, it is an object of embodiments to provide a
`method for producing a display device for which a repair
`operation can be carried out easily and reliably without dam(cid:173)
`age to a bonding portion by a cured resin.
`
`[0025] According to the above-described embodiments, an
`advantageous effect is achieved even when the storage elastic
`modulus of the cured resin layer is less than 1.0x105 Pa.
`[0026]
`In embodiments, the organic solvent can be selected
`from among organic solvents which are compatible when
`mixed with the resin composition before curing in a 1:1
`volume ratio.
`
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`US 2010/0178834 AI
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`Jul. 15, 2010
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`2
`
`In embodiments, the removing solution may contain
`[0027]
`limonene or toluene as the organic solvent.
`In embodiments, the removing solution may con(cid:173)
`[0028]
`tain, in addition to limonene, ethyl alcohol or isopropyl alco(cid:173)
`hol as the organic solvent.
`[0029]
`In embodiments, the protective part may be formed
`from a polymer material, and the removing solution contains
`limonene as the organic solvent.
`[0030] According to embodiments, an advantageous effect
`is achieved even when the display device is a liquid crystal
`display device in which a polarizing plate is provided on a
`surface of the display part.
`[0031] According to embodiments, after the display part
`and the protective part are bonded via a cured resin layer, if
`any defects are found, the display part and the protective part
`are separated by a wire having a smaller diameter than the
`thickness of the cured resin layer. The wire is then brought
`into contact with a side face of the cured resin layer where the
`protective part and the display part are bonded, and the wire is
`made to move through the cured resin layer. Afterwards, the
`cured resin layer adhered to the separated display part and the
`protective part is peeled off and removed using a removing
`solution comprising an organic solvent. Since a procedure for
`peeling off the display part and the protective part is not
`conducted during the repair operation, the display part and the
`protective part are not damaged by, for example, scratching
`and cracking.
`In one embodiment, the display part and the protec(cid:173)
`[0032]
`tive part can be separated by cutting the cured resin layer more
`smoothly and quickly when the modulus of elasticity of the
`cured resin layer is less than l.Ox105 Pa.
`[0033] According to one embodiment, by selecting an
`organic solvent that is compatible when mixed with the resin
`composition before curing in a 1: 1 volume ratio (for example,
`limonene or toluene), the cured resin layer that is adhered to
`the separated display part and the protective part can be dis(cid:173)
`solved and removed smoothly and reliably.
`[0034] Moreover, in embodiments, with respect to the
`removing solution, when a solvent containing limonene or
`toluene is selected in the organic solvent, change of properties
`of the polarizing plate provided on the surface of the display
`part does not result.
`[0035] Furthermore, if ethyl alcohol or isopropyl alcohol is
`used in addition to limonene as the organic solvent in the
`removing solution, the removing solution is capable of
`improving the peeling properties of the cured resin, and thus
`improves operational efficiency by increasing volatility of the
`removing solution.
`[0036] According to one aspect of the present disclosure,
`especially for a liquid crystal display device in which a polar(cid:173)
`izing plate is provided on the surface of a display part, a repair
`operation can be carried out easily and quickly.
`[0037] As discussed above, one embodiment provides a
`method for producing a display device of which a repair
`operation can be carried out easily and reliably without dam(cid:173)
`age to a bonding portion caused by the cured resin.
`[0038] Embodiments of the present disclosure will now be
`described in detail with reference to the drawings.
`[0039] FIG. 1 is a flow diagram illustrating an example of a
`method for producing a display device according to an
`embodiment.
`[0040] FIGS. 2(a) to (c) and FIGS. 3(a) to (c) are cross(cid:173)
`sectional views schematically illustrating the method for pro(cid:173)
`ducing the display device according an embodiment.
`
`[0041] As shown in FIG. 2(a), aresincompositionlayer4 is
`coated and formed by, for example, dropping a photocurable
`resin composition (referred to as "resin composition,"
`"resin," or the like, hereinafter) in a predetermined amount
`onto the surface of a display part 2 (step S1).
`[0042]
`In embodiments, this resin composition layer 4 can
`also be formed by a printing method.
`[0043]
`In embodiments, a spacer for determining the dis(cid:173)
`tance between the display part 2 and a protective part 3 is not
`required to be used. Instead, as an example, the distance
`between the display part 2 and the protective part 3 can be
`determined by a positioning means (not shown). However,
`the present disclosure is not meant to be limited to such
`embodiments and, thus, in various embodiments a spacer can
`also be used.
`In various embodiments, including a liquid crystal
`[0044]
`display device, a polarizing plate (not shown) is provided on
`the display part 2.
`[0045] As a protective part, in embodiments, a light-trans(cid:173)
`mitting glass plate or a substrate formed of a polymer material
`(plastic) such as an acrylic resin (for example, PMMA: poly(cid:173)
`methyl methacrylate) may be suitably used as the protective
`part 3.
`[0046] Such a protective part 3 is lowered while being kept
`in a horizontal state, and the protective part 3 is then fixed at
`a predetermined position by a positioning hoist mechanism
`(not shown).
`[0047] As shown in FIG. 2(b), the resin composition layer
`4 is placed and fills a gap between the display part 2 and the
`protective part 3 (step S2).
`[0048] As a photocurable resin composition, in embodi(cid:173)
`ments, a resin composition which has, after curing, a trans(cid:173)
`mittance of90% or higher, a storage elastic modulus at 25° C.
`of 1.0x 105 Pa or less, and a curing shrinkage ratio of 5% or
`less can be used.
`[0049] According to one embodiment, the viscosity of the
`photocurable resin composition is not especially limited.
`However, from the perspective of the wet spreading speed and
`tendency not to run over (surface tension), in embodiments, a
`photocurable resin composition having a viscosity in a range
`ofl,OOOmPa·s to 5,000mPa·s, such as arangeof2,000mPa·s
`to 3,000 mPa·s, can be used.
`[0050] More specifically, the photocurable resin composi(cid:173)
`tion may have a photoreactive acrylate material, such as poly(cid:173)
`urethane acrylate and isobornyl acrylate, and a photopoly(cid:173)
`merization initiator as main components, and may include
`additional additives, such as a sensitizing agent, a plasticizer,
`transparent particles and the like, within the scope of the
`object of the present disclosure.
`[0051] Examples of the photopolymerization initiator
`which may be used include 1-hydroxy-cyclohexyl-phenyl(cid:173)
`ketone (sold under the name "IRGACURE 184" manufac(cid:173)
`tured by Ciba Specialty Chemicals Inc.), and the like.
`[0052] The protective part 3 may be provided with a UV(cid:173)
`region cutting function in order to protect the display part 2
`against UV rays. In such an embodiment, as the photopoly(cid:173)
`merization initiator used in the present embodiment, it is
`beneficial to use a photopolymerization initiator that can cure
`the resin composition even in the visible light region (for
`example, sold under the name SPEEDCURE TPO, manufac(cid:173)
`tured by Nihon SiberHegner KK).
`[0053]
`In embodiments, the resin composition is prepared
`such that the cured resin obtained by curing the resin compo(cid:173)
`sition with UV irradiation has a storage elastic modulus (at
`
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`Jul. 15, 2010
`
`3
`
`25° C.) of 1x105 Pa or less, such as 1x103 to 1x105 Pa, a
`refractive index of1.45 or more to 1.55 or less, such as 1.51 or
`more to 1.52 or less, and a transmittance of 90% or higher in
`the visible light region when the cured resin has a thickness of
`100 p.m. Even when the major resin components constituting
`the resin composition are the same, if an additional resin
`component or monomer component added to the major resin
`components is different, the cured resin formed by curing
`such a curable resin composition may have a storage elastic
`modulus (at 25° C.) that exceeds 1x105 Pa.
`In embodiments, the resin composition is prepared
`[0054]
`so as to have a curing shrinkage ratio of 5.0% or less, such as
`4.5% or less, 4.0% or less, or 0 to 2%. Consequently, the
`internal stress that builds up in the cured resin during curing
`of the resin composition can be reduced, and distortion at the
`interface between the cured resin layer 5 and the display part
`2 or the protective part 3 can be prevented.
`[0055] When the resin composition is arranged between the
`display part 2 and the protective part 3 and then cured, the
`amount of light scattered at the interface between the cured
`resin layer 5 and the display part 2 or the protective part 3 can
`be reduced. As a result, the luminance and the visibility of the
`display image can be improved.
`[0056] The magnitude of the internal stress that builds up in
`the cured resin during curing can be evaluated by dropping the
`resin composition onto a flat plate, curing the resin composi(cid:173)
`tion, and measuring the average surface roughness of the
`resulting cured resin. In practice, the distortion generated at
`the interface between the display part or the protective part
`and the cured resin composition arranged therebetween can
`be disregarded if, for example, a cured resin evaluated by
`dropping 2 mg of the resin composition onto a glass plate or
`an acrylic plate and cured by UV irradiation to a 90% or
`higher cure ratio has an average surface roughness of 6.0 nm
`or less. However, regarding the resin composition of the
`present disclosure, this average surface roughness can be
`maintained at 6.0 nm or less, such as 5.0 or less; or in the range
`of 1 to 3 nm.
`[0057] As a plate, in embodiments, a glass plate for sand(cid:173)
`wiching the liquid crystals of a liquid crystal cell, or used as
`a protective plate for a liquid crystal cell can be used.
`[0058] Furthermore, in embodiments, an acrylic plate can
`also be used as the protective plate for a liquid crystal cell.
`Such glass plates or acrylic plates typically have an average
`surface roughness of 1.0 nm or less.
`[0059] Subsequently, as shown in FIG. 2(c), the resin com(cid:173)
`position layer 4 is irradiated with UV rays via the protective
`part 3 to cure the resin (step S3).
`[0060] According to embodiments, the irradiation direction
`of the UV rays is not especially limited. However, from the
`standpoint of achieving more uniform curing of the resin, a
`direction perpendicular to the surface of the protective part 3
`of the display part 2 is suitable.
`[0061] UV rays may also be simultaneously directly irra(cid:173)
`diated from the external side face of the resin composition
`layer 4 between the display part 2 and the protective part 3,
`using an optical fiber, for example.
`[0062] Then, in step S4, the presence offoreign substances
`or air bubbles mixed in the cured resin layer 5 that is filled
`between the display part 2 and the protective part 3 is
`checked.
`In step S5, if the result of the check is favorable, the
`[0063]
`method is finished.
`
`[0064] On the other hand, if a defect, such as foreign sub(cid:173)
`stances or air bubbles being mixed in the cured resin layer 5
`between the display part 2 and the protective part 3, is con(cid:173)
`firmed, a repair operation is carried out.
`[0065] As part of the repair operation, in step S6, the dis(cid:173)
`play part 2 and the protective part 3 are separated by cutting
`the cured resin layer 5 using a wire 20, as illustrated in FIGS.
`3(a) and 3(b).
`[0066] FIGS. 4 and 5 are explanatory diagrams illustrating
`embodiments of a method for cutting a cured resin layer
`according to the present disclosure.
`In the embodiment illustrated in FIG. 4, the wire 20
`[0067]
`is passed over a pair of pulleys 10 and 11. The cured resin
`layer 5, located between the display part 2 and the protective
`part 3, is pressed against the wire 20 while the wire 20 is slid
`in a left-right direction as shown in FIG. 4, which corresponds
`to the width direction of the display part 2 and the protective
`part 3. Then, a panel1 is moved in a direction orthogonal to
`the wire 20 so as to cut the cured resin layer 5 and thereby
`separate the display part 2 and the protective part 3.
`In the embodiment illustrated in FIG. 5, the wire 20
`[0068]
`is passed over a plurality of pulleys 10 to 13 which are
`arranged so as to form a pair of pulley blocks. Furthermore,
`tension springs 14 and 15, for absorbing slack in the wire 20
`between the pulleys 10 and 11, are connected to the pulleys 12
`and 13, respectively, which move as a pulley block.
`In another embodiment, the cured resin layer 5
`[0069]
`between the display part 2 and the protective part 3 is pressed
`against the wire 20. Then, the panel1 is moved in a direction
`orthogonal to the wire 20 to cut the cured resin layer 5 and
`thereby separate the display part 2 and the protective part 3.
`[0070] Here, the slack in the wire 20 between the pulleys 10
`and 11 is absorbed by the elastic force of the tension springs
`14 and 15, such that the wire 20 between the pulleys 10 and 11
`is constantly in a taut state.
`[0071] As the wire 20 used in embodiments, a metal wire,
`such as one made of carbon steel, (for example, piano wire) or
`the like can be used.
`[0072] The thickness (diameter) of the wire 20 is not espe(cid:173)
`cially limited, as long as it is less than the thickness of the
`cured resin layer 5 between the display part 2 and the protec(cid:173)
`tive part 3. However, from the perspective of cutting perfor(cid:173)
`mance, a suitable thickness of a wire can be in the range of 50
`f.tm to 100 f.tm.
`[0073] After the display part 2 and the protective part 3 have
`thus been separated, in step S7, the cured resin remaining on
`the surfaces of the display part 2 and the protective part 3 is
`wiped away by a removing solution containing an organic
`solvent (step S7).
`[0074] FIGS. 6(a) to (c) are explanatory diagrams sche(cid:173)
`matically illustrating a method for wiping away a cured resin
`by an organic solvent.
`[0075] FIGS. 6(a) and 6(b) illustrate an embodiment where
`the resin composition on the display part (for example, LCD
`cell) or protective part (for example, plastic plate or glass
`plate) is cured by the irradiation ofUV rays.
`[0076] According to embodiments, as illustrated in FIG.
`6(c), an organic solvent-containing removing solution is
`coated by dropping or spraying, for example, onto the cured
`resin. The coated cured resin is then left for approximately 5
`minutes at room temperature, for example, to impregnate the
`removing solution into the cured resin, which then swells.
`[0077] The cured resin is then wiped away using a wipe
`member formed of an elastomer or the like which is impreg-
`
`10 of 13
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`US 2010/0178834 AI
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`Jul. 15, 2010
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`4
`
`nated with the same solvent as the organic solvent of the
`removing solution that was coated on the cured resin.
`[0078] As the organic solvent contained in the removing
`solution, an organic solvent which is compatible when mixed
`with the resin composition before curing in a 1:1 volume
`ratio, or more specifically, an organic solvent having a small
`solution parameter (SP value), can be used. In embodiments,
`an organic solvent having a solution parameter of less than 9
`can be suitably used.
`[0079]
`In embodiments, by using a removing solution con(cid:173)
`taining such an organic solvent, the cured resin remaining on
`the surfaces of the display part 2 and the protective part 3 can
`be completely removed.
`[0080] For a liquid crystal display device, it is preferable to
`use an organic solvent which does not cause damage to the
`device, such as, for example, changes to the polarizing plate
`(made oftriacetyl cellulose) provided on the display part 2.
`[0081] According to one embodiment, as organic solvents
`which satisfy the above requirements, suitable organic sol(cid:173)
`vents include limonene (C 10H 16, solution parameter: 0.6) or
`toluene (C7 H8 , solution parameter: 8.8).
`[0082]
`In order to improve the wiping properties and vola(cid:173)
`tility, ethyl alcohol or isopropyl alcohol may be added to the
`removing solution. From the perspective of improving safety,
`limonene is a suitable organic solvent.
`[0083] When a substrate formed of a polymer material ( es(cid:173)
`pecially a PMMA substrate) is used as the protective part 2,
`limonene may be used as the organic solvent, allowing the
`cured resin to be wiped away without causing any changes to
`the surface of the substrate.
`[0084] Further, if the organic solvent is limonene, the wip(cid:173)
`ing properties and volatility can be improved by adding ethyl
`alcohol and/or isopropyl alcohol.
`[0085] After the wiping step, the wiped surfaces of the
`display part 2 and the protective part 3 are examined to
`observe any changes in the appearance with, for example, in
`step S8. If there is no cured resin residue present and no
`changes on the surface have occurred, the process returns to
`step S1, and the above-described steps are repeated from the
`start in step S9.
`[0086] Alternatively, if in step S9, there is a cured resin
`residue remaining on the surfaces of the display part 2 and the
`protective part 3, or if surface changes have occurred, the
`produced display device is treated as a defective product.
`[0087] The present disclosure is not limited to the above(cid:173)
`discussed embodiments, and various modifications can be
`made thereto.
`[0088] For example, in the above-discussed embodiment,
`the display device was moved against the wire when cutting
`the cured resin layer 5. However, the present disclosure is not
`limited thereto and the wire may be moved against the display
`device.
`[0089]
`In addition, the present disclosure is not limited to
`the above-discussed liquid crystal display device. For
`example, the present invention may also be applied to various
`flat panel display panels, such as an organic EL device.
`
`Examples
`[0090] Embodiments will now be described in more detail
`using the following examples and comparative examples.
`However, the present invention is not limited to the following
`embodiments.
`
`from a maleic anhydride adduct of a polyisoprene polymer
`and 2-hydroxyethyl methacrylate, 30 parts by weight of dicy(cid:173)
`clopentenyl oxyethyl methacrylate, 10 parts by weight of
`2-hydroxybutyl methacrylate, 30 parts by weight of a terpene
`series hydrogenated resin, 140 parts by weight of a butadiene
`polymer, 4 parts by weight of a photopolymerization initiator,
`and 0.5 parts by weight of a visible light region photopoly(cid:173)
`merization initiator.
`
`Physical Properties of the Cured Resin According to
`the Present Invention
`
`Reference Example
`
`Transmittance and Modulus of Elasticity
`
`[0092] The resin composition prepared in the above-de(cid:173)
`scribed blend was dropped onto a white glass plate having
`thickness of 100 f.tm, to be used as a protective part. The plate
`was transferred by a UV-conveyor in a UV-ray irradiation
`apparatus to cure the resin. The thickness of the cured resin
`was 1 00 flill·
`[0093] The transmittance of this cured resin was measured
`using a UV-Visible Spectrophotometer (V-560, JASCO Cor(cid:173)
`poration) to be 90% or higher.
`[0094] Next, using a viscoelastometer (sold under the name
`"DMS6100", manufactured by Seiko Instruments Inc.), the
`modulus of elasticity (measurement frequency 1 Hz, 25° C.)
`of the cured resin was measured and the measured result was
`l.Ox104 Pa.
`
`[Curing Shrinkage Ratio]
`
`[0095] For the curing shrinkage ratio, specific gravities of
`the resin solution before curing, and the cured solid product
`were measured by an electronic densimeter (sold under the
`name "SD-120L", manufactured by Mirage). The curing
`shrinkage ratio is calculated by the following equation based
`on the difference of the specific gravities between the resin
`solution before curing and the cured solid product. In the
`present example, curing shrinkage ratio was 1.8%.
`
`Curing shrinkage ratio(%)~(Cured product specific
`gravity-Resin solution specific gravity)/Cured product
`specific gravityx 100
`
`[Surface Roughness Measurement]
`
`[0096] 2 mg of the above resin composition was dropped
`onto a glass plate for an LCD cell. The distortion (Ra: average
`surface roughness) in a predetermined region (2.93 mmx2.20
`mm) of the glass plate surface due to the internal stress gen(cid:173)
`erated during the curing reaction by the UV irradiation was
`measured by a three-dimensional non-contact surface rough(cid:173)
`ness meter (such as those manufactured by Zygo K.K.) and
`the measured result was 2.7 nm.
`[0097]
`In the present example, the cured resin had a modu(cid:173)
`lus of elasticity of 1x104 Pa and a curing shrinkage ratio of
`1.8%. Consequently, the average surface roughness Ra was
`2.7 nm, and there was hardly any distortion, meaning that
`superior results were obtained. Therefore, a display device
`which is free from distortion can be obtained by arranging and
`filling such a cured resin between the display part and the
`protective part.
`
`[Preparation of Coating Solution]
`[0091] A resin composition was prepared by kneading in a
`kneader 70 parts by weight of an ester compound formed
`
`Examples and Comparative Examples
`[0098] As shown in FIG. 6(a), the above-discussed resin
`composition was coated onto the above-described glass plate
`
`11 of 13
`
`

`

`US 2010/0178834 AI
`
`Jul. 15, 2010
`
`5
`
`for a protective part or glass plate for an LCD cell. Then, as
`shown in FIG. 6(b), the resin composition was cured by
`irradiating with UV rays.
`[0099] Next, as shown in FIG. 6(c), limonene, toluene, or
`MEK was coated onto the cured resin as an organic solvent,
`and the coated cured resin was left for 5 minutes at room
`temperature.
`[0100] Furthermore, by using a wipe member impregnated
`with the same organic solvent as that coated on the cured
`resin, the cured resin was wiped away.
`[0101] Subsequently, the wiping properties of each sample
`were confirmed using a microscope to observe any changes in
`the appearance of each sample. These results are shown in
`Table 1.
`In Table 1,