U.S. patent application number 14/184795 was filed with the patent office on 2014-06-19 for glass film laminate.
This patent application is currently assigned to Nippon Electric Glass Co., Ltd.. The applicant listed for this patent is Nippon Electric Glass Co., Ltd.. Invention is credited to Hirokazu OKAMOTO, Tatsuya TAKAYA, Hiroshi TAKIMOTO, Masahiro TOMAMOTO.
Application Number | 20140166186 14/184795 |
Document ID | / |
Family ID | 43411021 |
Filed Date | 2014-06-19 |
United States Patent
Application |
20140166186 |
Kind Code |
A1 |
TAKAYA; Tatsuya ; et
al. |
June 19, 2014 |
GLASS FILM LAMINATE
Abstract
A glass film laminate includes a glass film and a supporting
glass. The glass film and the supporting glass have surfaces in
contact with each other, and each of the surfaces has a surface
roughness Ra of 2.0 nm or less.
Inventors: |
TAKAYA; Tatsuya; (Shiga,
JP) ; TOMAMOTO; Masahiro; (Shiga, JP) ;
TAKIMOTO; Hiroshi; (Shiga, JP) ; OKAMOTO;
Hirokazu; (Shiga, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nippon Electric Glass Co., Ltd. |
Shiga |
|
JP |
|
|
Assignee: |
Nippon Electric Glass Co.,
Ltd.
Shiga
JP
|
Family ID: |
43411021 |
Appl. No.: |
14/184795 |
Filed: |
February 20, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12826965 |
Jun 30, 2010 |
8697241 |
|
|
14184795 |
|
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|
Current U.S.
Class: |
156/73.1 ;
156/247 |
Current CPC
Class: |
B32B 3/02 20130101; C03B
17/02 20130101; B32B 17/06 20130101; C03B 17/064 20130101; B32B
7/06 20130101; Y10T 428/24331 20150115; B32B 37/14 20130101; Y10T
428/31 20150115; B32B 3/266 20130101; Y10T 428/24612 20150115; B65G
49/069 20130101; Y10T 428/266 20150115; Y10T 428/24752 20150115;
G02F 1/133305 20130101; Y10T 428/2495 20150115; H01L 51/0096
20130101; G02F 2202/09 20130101; Y10T 428/26 20150115; B32B 38/10
20130101; Y10T 428/315 20150115; H05B 33/04 20130101; Y10T
428/24182 20150115; C03B 23/203 20130101; Y10T 428/24777 20150115;
Y10T 428/24942 20150115 |
Class at
Publication: |
156/73.1 ;
156/247 |
International
Class: |
B32B 37/14 20060101
B32B037/14; B32B 38/10 20060101 B32B038/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 3, 2009 |
JP |
2009-158850 |
Feb 12, 2010 |
JP |
2010-028743 |
Claims
1-11. (canceled)
12. A method of producing a glass film comprising the steps of:
laminating a glass film and a supporting glass to prepare a glass
film laminate, a surface of the glass film and a surface of the
supporting glass, which are in contact with each other, having a
surface roughness Ra of 2.0 nm or less respectively, the glass film
having a thickness of 5 to 200 .mu.m; performing a treatments
associated with electronic device production on the glass film of
the glass film laminate; and then separating the glass film and the
supporting glass from each other.
13. The method of producing a glass film according to claim 12,
wherein the step of separating is performed by immersing the glass
film laminate in water.
14. The method of producing a glass film according to claim 13,
wherein the step of separating is performed while applying an
ultrasonic wave to the glass film laminate.
15. The method of producing a glass film according to claim 12,
wherein the supporting glass has a thickness of 400 .mu.m or
more.
16. The method of producing a glass film according to claim 12,
wherein each of the glass film and the supporting glass is formed
by an over down-draw method.
Description
TECHNICAL FIELD
[0001] The present invention relates to a glass film laminate in
which a glass film is supported with a supporting glass, the glass
film being used for a flat panel display such as a liquid crystal
display and an OLED display, a glass substrate for devices such as
a solar cell, a lithium ion battery, a digital signage, a touch
panel, and an electronic paper, a cover glass for devices such as
an organic LED (OLED) lighting device, a package for a medicinal
product, and the like.
BACKGROUND ART
[0002] In recent years, From the viewpoint of space saving, in
place of a CRT type display conventionally and widely used, there
have been widely used, flat panel displays such as a liquid crystal
display, a plasma display, an OLED display, and a field emission
display. Further reduction in thickness is demanded for these flat
panel displays. In particular, it is required that the OLED display
be easily carried by being folded or wound and be usable not only
on a flat surface but also on a curved surface. Further, it is not
just displays that are required to be usable not only on a flat
surface but also on a curved surface. For example, if a solar cell
or an OLED lighting device can be formed on a surface of an object
having a curved surface, such as a surface of an automobile body,
or a roof, a pillar, or an outer wall of a building, the
applications of the solar cell or OLED lighting device may expand.
Substrates and cover glasses used for these devices are required to
be a thinner sheet and to have high flexibility.
[0003] A light-emitting element used for an OLED display
deteriorates in quality through the contact of gasses such as
oxygen and water vapor. Thus, a substrate used for the OLED display
is required to have high gas-barrier property, and hence the use of
a glass substrate for the substrate is expected. However, glass
used for a substrate is weak in tensile stress unlike a resin film,
and hence is low in flexibility. Thus, concentration of a tensile
stress on a surface of a glass substrate by bending the glass
substrate leads to the breakage of the glass substrate. In order to
impart flexibility to the glass substrate, the glass substrate is
required to achieve an ultra thin sheet. Thus, a glass film having
a thickness of 200 .mu.m or less is proposed as described in Patent
Document 1 below.
[0004] A glass substrate used for electronic devices such as a flat
panel display and a solar cell is subjected to various treatments
associated with electronic device production, such as a treatment
for providing a film such as a transparent conductive film and a
cleaning treatment. However, when a glass film is used as a glass
substrate for these electronic devices, the glass film breaks due
to a stress change even at a small amount, because glass is a
brittle material. Thus, there is a problem in that the handling of
the glass film is very difficult, when the above-mentioned various
treatments associated with electronic device production are carried
out. In addition, there is another problem in that a glass film
having a thickness of 200 .mu.m or less is rich in flexibility, and
hence the positioning of the glass film is difficult when the
treatments associated with production are carried out, so that
displacement or the like in patterning may occur.
[0005] Therefore, in order to enhance a handling easiness of a
glass film, proposed is a laminate in which a glass film is
laminated on a resin film after a pressure-sensitive adhesive
substance is coated on the resin film. In such the glass film
laminate, the glass film is supported by the resin film being a
tough material, and hence the handling of the glass film laminate
becomes easier compared to a case of the glass film alone when the
above-mentioned various treatments associated with production are
carried out.
[0006] However, there is a problem in that when the resin film is
finally peeled off from the laminate to provide a glass film
solely, the glass film which is a brittle material is easy to
break, and the pressure-sensitive adhesive substance remains on the
glass film after the resin film is peeled off, causing
contamination. Further, there is a difference in thermal expansion
coefficients of the resin film and the glass film, and hence, even
in a case where a heat treatment is carried out at a relatively low
temperature of around 200.degree. C. as a treatment associated with
production, there is a possibility in that thermal warpage, resin
peeling, or the like may occur. In addition, there is another
problem in that displacement or the like easily occurs when the
positioning and the patterning during treatments associated with
production are carried out, because the resin film is also rich in
flexibility.
[0007] In order to solve the above-mentioned problems, a laminate
is proposed as described in Patent Document 2 below. Patent
Document 2 below proposes a laminate in which a supporting glass
and a glass sheet are laminated via a pressure-sensitive adhesive
layer that may be maintained almost stably even after its repeated
use. According to such the laminate, even if a glass sheet having
less strength and rigidity by itself is used, the production of a
liquid crystal display device may be carried out with sharing a
conventional line for producing a liquid crystal display device.
Thus, after completion of the production processes, peeling off the
glass sheet can be carried out quickly without the breakage of the
glass substrate. Further, the thermal warpage or the like can be
prevented from occurring to some extent, because the supporting
member is made of glass. In addition, displacement or the like
hardly occurs when the positioning and patterning during treatments
associated with production are carried out, because the support
member has high rigidity.
[0008] However, even in the above-mentioned laminate, there has not
yet been solved such a problem that a pressure-sensitive adhesive
remains on the thin glass sheet after peeling off of the supporting
glass.
PRIOR ART DOCUMENTS
Patent Document
[0009] Patent Document 1: JP 2008-133174 A [0010] Patent Document
2: JP 1996-86993 A
SUMMARY OF INVENTION
Technical Problem
[0011] The present invention has been made to solve the
above-mentioned problems with prior arts. That is, an object of the
present invention is to provide a glass film laminate, which has an
enhanced handling easiness of a glass film when the glass film is
subjected to treatments associated with production, does not cause
a problem such as displacement at the time of positioning and
patterning, enables easy peeling off the glass film from a
supporting glass when the glass film is incorporated into each of
various devices after the treatments associated with production,
and which reliably prevents an occurrence of a residual of a
pressure-sensitive adhesive on the glass film after peeling off the
glass film.
Solution to Problem
[0012] The invention according to a first aspect relates to a glass
film laminate, comprising a glass film and a supporting glass,
wherein a surface of the glass film and a surface of the supporting
glass, which are brought into contact with each other, have a
surface roughness Ra of 2.0 nm or less respectively.
[0013] The invention according to a second aspect relates to a
glass film laminate according to the first aspect, wherein the
surface of the glass film and the surface of the supporting glass
have a GI value of 1000 pcs/m.sup.2 or less respectively.
[0014] The invention according to a third aspect relates to a glass
film laminate according to the first or second aspect, wherein the
glass film has a thickness of 300 .mu.m or less.
[0015] The invention according to a fourth aspect relates to a
glass film laminate according to the first to third aspects,
wherein the supporting glass has a thickness of 400 .mu.m or
more.
[0016] The invention according to a fifth aspect relates to a glass
film laminate according to the first to fourth aspects, wherein a
difference of thermal expansion coefficients between the glass film
and the supporting glass at 30 to 380.degree. C. falls within
5.times.10.sup.-7/.degree. C.
[0017] The invention according to a sixth aspect relates to a glass
film laminate according to the first to fifth aspects, wherein the
glass film and the supporting glass are formed by an overflow
down-draw method.
[0018] The invention according to a seventh aspect relates to a
glass film laminate according to the first to sixth aspects,
wherein the glass film and the supporting glass are laminated so
that at least a part of an edge portion includes a step.
[0019] The invention according to an eighth aspect relates to a
glass film laminate according to the first to seventh aspects,
wherein a peeling sheet member is interposed at a partial region of
a contact portion between the glass film and the supporting glass,
and the peeling sheet member partially protrudes from the contact
portion.
[0020] The invention according to a ninth aspect relates to a glass
film laminate according to the first to eighth aspects, wherein the
supporting glass includes at least one through-hole formed at a
position being outside of an effective surface of the glass
film.
[0021] The invention according to a tenth aspect relates to a glass
film laminate according to the first to ninth aspects, wherein the
glass film laminate includes a guide member for positioning the
glass film on the supporting glass at the glass film side.
[0022] The invention according to an eleventh aspect relates to a
glass film laminate according to the tenth aspect, wherein the
guide member has a smaller thickness than the glass film.
Effects of Invention
[0023] According to the invention of the first aspect, since the
glass film laminate is constituted by the supporting glass and the
glass film, the glass film laminate enhances handling easiness of
the glass film when the glass film is subjected to treatments
associated with production, and can prevent occurrence of problems
such as a positioning error and displacement in patterning. The
surface of the glass film and the surface of the supporting glass,
which are brought into contact with each other, have a surface
roughness Ra of 2.0 nm or less respectively, and the glass film and
the supporting glass are brought into contact with each other with
such the smooth surfaces. As a result, the glass film and the
supporting glass are in a close contact, thereby, it is possible to
laminate the glass film and the supporting glass firmly and stably
without use of adhesive. No adhesive is used, and hence, when the
glass film is incorporated into any of various devices after the
treatments associated with production, peeling off even one portion
of the glass film from the supporting glass enables easy subsequent
peeling off the whole glass film from the supporting glass. In
addition, the glass film is free from any remaining adhesive.
[0024] On the other hand, if the surface roughness Ra exceeds 2.0
nm, the close contact decreases. As a result, it is not possible to
laminate the glass film and the supporting glass firmly without use
of adhesive.
[0025] According to the invention of the second aspect, since the
surface of the glass film and the surface of the supporting glass,
which are brought into contact with each other, have a GI value of
1000 pcs/m.sup.2 or less respectively, the contacting surfaces of
the glass film and supporting glass are clean, leading to undamaged
activity of the surfaces. As a result, it is possible to laminate
the glass film and the supporting glass more firmly and more stably
without use of adhesive.
[0026] According to the invention of the third aspect, since the
glass film has a thickness of 300 .mu.m or less, even in an
ultra-thin glass film, which is more difficult to handle and is
easily involved in problems such as a positioning error and
displacement in patterning, treatments associated with production
can be easily carried out.
[0027] According to the invention of the fourth aspect, since the
supporting glass has a thickness of 400 .mu.m or more, the
supporting glass can securely support the glass film.
[0028] According to the invention of the fifth aspect, since the
difference of thermal expansion coefficients between the glass film
and the supporting glass at 30 to 380.degree. C. falls within
5.times.10.sup.-7/.degree. C., even when a heat treatment is
carried out during treatments associated with production, a glass
film laminate can hardly have a thermal warpage or the like.
[0029] According to the invention of the sixth aspect, since the
glass film and the supporting glass are formed by the overflow
down-draw method, the surfaces thereof have extremely high in
surface precision without being subjected to a polishing process.
As a result, the glass film and the supporting glass can be
laminated more firmly.
[0030] According to the invention of the seventh aspect, since the
glass film and the supporting glass are laminated so that at least
a part of an edge portion includes a step, in the case where the
glass film protrudes from the supporting glass, it is possible to
peel off the glass film and the supporting glass from each other
more easily in a more secure manner. On the other hand, in the case
where the supporting glass protrudes from the glass film, it is
possible to properly protect an end portion of the glass film from
striking, or the like.
[0031] According to the invention of the eighth aspect, since the
peeling sheet member is interposed at a partial region of the
contact portion between the glass film and the supporting glass,
and the sheet member partially protrudes from the contact portion,
it is possible to peel off the glass film and the supporting glass
from each other more easily in a more secure manner while grasping
the protruding portion of the sheet member.
[0032] According to the invention of the ninth aspect, since the
supporting glass includes at least one through-hole formed at a
position being outside of an effective surface of the glass film,
when the glass film is peeled off from the supporting glass, it is
possible to raise up the glass film only by injecting compressed
air or inserting a pin or the like through the through-hole,
resulting in easily starting peeling off the glass film.
[0033] According to the invention of the tenth aspect, since the
glass film laminate includes a guide member for positioning the
glass film on the supporting glass at the glass film side, it is
possible to easily position the glass film with respect to the
supporting glass when the glass film is laminated on the supporting
glass.
[0034] According to the invention of the eleventh aspect, since the
guide member has a smaller thickness than the glass film, when the
glass film laminate is subjected to a cleaning treatment as one of
the treatments associated with production, it is possible to
prevent a liquid from remaining on the surface of the glass
film.
BRIEF DESCRIPTION OF DRAWINGS
[0035] FIG. 1 is a cross-sectional view of a glass film laminate
according to the present invention.
[0036] FIG. 2 is an explanatory diagram of a manufacturing
apparatus for a glass film and a supporting glass.
[0037] FIG. 3(a) is a view of a glass film laminate in which a
glass film and a supporting glass are laminated with a step at an
edge portion of the glass film laminate, for showing a state in
which the supporting glass protrudes from the glass film.
[0038] FIG. 3(b) is a view showing a state in which the glass film
protrudes from the supporting glass.
[0039] FIG. 3(c) is a view showing a state in which a notch is
formed in the supporting glass.
[0040] FIG. 4(a) is a plan view showing a state in which a
through-hole is formed in a supporting glass.
[0041] FIG. 4(b) is a cross-sectional view taken along the line A-A
of FIG. 4(a).
[0042] FIG. 5(a) is a plan view showing a state in which guide
members are provided on a supporting glass.
[0043] FIG. 5(b) is a cross-sectional view taken along the line B-B
of FIG. 5(a).
DETAILED DESCRIPTION OF THE INVENTION
[0044] Hereinafter, preferred embodiments of a glass film laminate
according to the present invention are described with reference to
the drawings.
[0045] A glass film laminate (1) according to the present invention
comprises a glass film (2) and a supporting glass (3) as shown in
FIG. 1. The glass film (2) and the supporting glass (3) are
laminated without using adhesive, or the like.
[0046] For the glass film (2), silicate glass is used, silica glass
or borosilicate glass is preferably used, or alkali-free glass is
most preferably used. If the glass film (2) contains an alkali
component, a cation is detached from a surface of the glass film,
leading to occurrence of a so-called too-abundant soda phenomenon
and resulting in a coarse structure. In this case, if the glass
film (2) is continuously used in a bent state, the glass film (2)
may break at a portion of being coarse because of aging
degradation. Note that the alkali-free glass means glass
substantially free of an alkali component (alkali metal oxide), and
specifically, glass that contains the alkali component at a weight
ratio of 1000 ppm or less. The content of the alkali component in
the present invention is preferably 500 ppm or less, or more
preferably 300 ppm or less.
[0047] The glass film (2) has a thickness of preferably 300 .mu.m
or less, more preferably 5 .mu.m to 200 .mu.m, or most preferably 5
.mu.m to 100 .mu.m. With this, a thickness of the glass film (2)
may be made thinner to impart an appropriate flexibility to the
glass film (2). Further, in this case, treatments associated with
production can be easily carried out with respect to the glass film
(2), which is hard to handle and easily causes problems such as a
positioning error and displacement in patterning. If the thickness
is less than 5 .mu.m, the glass film (2) tends to have insufficient
strength. As a result, when the glass film (2) is peeled off from
the glass film laminate (1) to be incorporated into a device, the
glass film (2) becomes liable to cause a breakage.
[0048] For the supporting glass (3), similar to the glass film (2),
silicate glass, silica glass, borosilicate glass, alkali-free
glass, or the like is used. The supporting glass (3) is preferably
made of glass that has a difference of thermal expansion
coefficients at 30 to 380.degree. C. with respect to the glass film
(2) falling within 5.times.10.sup.-7/.degree. C. With this, there
can be provided the glass film laminate (1) in which thermal
warpage or the like is not easily caused due to the difference in
thermal expansion coefficients even when a heat treatment is
carried out during treatments associated with production, and a
stable laminated state can be maintained.
[0049] The supporting glass (3) preferably has a thickness of 400
.mu.m or more. This is because if the supporting glass (3) has a
thickness of less than 400 .mu.m, the supporting glass (3) may have
a problem in strength when handling the supporting glass (3) alone.
The supporting glass (3) preferably has a thickness of from 400
.mu.m to 700 .mu.m, or most preferably from 500 .mu.m to 700 .mu.m.
With this, the glass film (2) can be securely supported, and it
becomes possible to effectively suppress a breakage that may occur
when the glass film (2) is peeled off from the supporting glass
(3).
[0050] Surface roughness Ra of each of the surfaces of the glass
film (2) and the supporting glass (3) on the sides being brought
into contact with each other is 2.0 nm or less. If the surface
roughness Ra exceeds 2.0 nm, close contact therebetween is lowered.
As a result, it is not possible to firmly laminate the glass film
(2) and the supporting glass (3) without use of adhesive. The
surfaces of the glass film (2) and supporting glass (3) have a
surface roughness Ra of preferably 1.0 nm or less, more preferably
0.5 nm or less, or most preferably 0.2 nm or less,
respectively.
[0051] GI value of each of the surface of the glass film (2) and
the surface of the supporting glass (3) on the sides being brought
into contact with each other is preferably 1000 pcs/m.sup.2 or
less. With this, the contacting surfaces of the glass film (2) and
supporting glass (3) are clean without loss of the activities of
the surfaces. As a result, it is possible to laminate the glass
film (2) and the supporting glass (3) more firmly and more stably
without use of adhesive. The GI value used in the present
specification refers to a number (pcs) of impurity particles having
a major diameter of 1 .mu.m or more and existing in a region of 1
m.sup.2. The surfaces of the glass film (2) and supporting glass
(3) have a GI value of preferably 500 pcs/m.sup.2 or less, or most
preferably 100 pcs/m.sup.2 or less, respectively.
[0052] The glass film (2) and the supporting glass (3) to be used
in the present invention are preferably formed by a down-draw
method. This is because the glass film (2) and the supporting glass
(3) can be formed so as to have a smoother surface. In particular,
the overflow down-draw method shown in FIG. 2 is a forming method
in which both surfaces of a glass sheet are not brought into
contact with a forming body during a forming process, and hence
flaws are hardly caused on the both surfaces (transparent surfaces)
of the obtained glass sheet, and high surface-quality may be
obtained for the glass sheet without polishing. With this, it is
possible to laminate the glass film (2) and the supporting glass
(3) more firmly.
[0053] A glass ribbon (G) immediately after being flown down from a
lower end portion (71) of a forming body (7) having a wedge shape
in cross-section is drawn downwardly while being restricted
shrinkage thereof in a width direction by cooling rollers (8), to
be thin in a predetermined thickness. Subsequently, the glass
ribbon (G) having the predetermined thickness is annealed in an
annealer to remove heat strain in the glass ribbon (G), followed by
cutting of the glass ribbon (G) into a predetermined size. As a
result, a glass sheet serving as the glass film (2) or the
supporting glass (3) is formed.
[0054] FIGS. 3(a) to 3(c) are views of a glass film laminate in
which a glass film and a supporting glass are laminated with a step
at an edge portion of the glass film laminate, in which: 3(a) is a
view showing a state in which the supporting glass protrudes from
the glass film; 3(b) is a view showing a state in which the glass
film protrudes from the supporting glass; and 3(c) is a view
showing a state in which a notch is formed in the supporting
glass.
[0055] The glass film laminate (1) according to the present
invention preferably has a structure in which, as shown in FIGS.
3(a) to 3(c), the glass film (2) and the supporting glass (3) are
laminated with a step (4). In FIG. 3(a), a step (41) is formed so
that the supporting glass (3) protrudes from the glass film (2).
With this, the end portion of the glass film (2) can be protected
more appropriately. On the other hand, in FIG. 3(b), a step (42) is
formed so that the glass film (2) is protruded from the supporting
glass (3). With this, when the peeling off of the glass film (2)
and the supporting glass (3) is started, only the glass film (2)
can easily be grasped, and hence the peeling off of the both can be
performed more easily in a more secure manner.
[0056] The step (4) may only be formed at least a part of the
peripheral portion of the glass film laminate (1). For example,
when the glass film laminate (1) has a rectangular shape in a
planar view, a step may only be formed at least one side out of the
four sides. Further, a notch (orientation flat) may be formed at a
part of one of the four corners of the supporting glass (3) or the
glass film (2), to thereby form a step.
[0057] In the configuration shown in FIG. 3(b), the protrusion
amount of the glass film (2) is preferably 0.5 mm to 20 mm. If the
protrusion amount is less than 0.5 mm, there is a possibility of
becoming hard to grasp the edge portion of the glass film (2) at
the time of the start of peeling off. And if the protrusion amount
exceeds 20 mm, there is a possibility of causing a breakage of the
glass film (2) when an external force such as striking is applied
to the side edge portion of the glass film laminate (1).
[0058] In addition, the glass film laminate (1) may have different
steps one of which is formed by protruding the edge portion of the
supporting glass (3) from the edge portion of the glass film (2)
and the other of which is formed by protruding the edge portion of
the glass film (2) from the edge portion of the supporting glass
(3), at the end portion of the glass film laminate (1). In this
case, each of the glass film (2) and the supporting glass (3) can
be grasped at the same time, and hence the glass film (2) can be
peeled off more easily. The respective steps are most preferably
formed adjacently to each other.
[0059] In addition, as shown in FIG. 3(c), in a case where the size
of the glass film (2) is smaller than the size of the supporting
glass (3), a notch portion (31) is preferably formed at an end
portion of the supporting glass (3). As a result, besides an
appropriate protection of the edge portion of the glass film (2),
when peeling off the glass film (2), the glass film (2) can be
easily grasped at the portion exposed from the notch portion (31)
of the supporting glass (3), thereby being capable of easily
peeling off the glass film (2). The notch portion (31) can be
formed by partially grinding an end portion of the supporting glass
(3) with a grinding stone, or the like, or by partially cutting out
an end portion with a core drill, or the like.
[0060] It is preferred that a peeling sheet member be interposed at
a partial region of the contact portion between the glass film (2)
and the supporting glass (3), while being protruded from the glass
film laminate (1). This is because the peeling off of the glass
film (2) can easily be carried out by grasping only the protruded
portion of the sheet member from the glass film laminate (1). Any
known resin sheet can be used as the sheet member. The thickness of
the sheet member is preferably thinner to such an extent that the
sheet member does not break when only the sheet member is pulled at
the time of peeling off the glass film (2). As long as the sheet
member may serve for peeling off the glass film (2), the sheet
member is not particularly limited in terms of an interposing
amount and the protrusion amount. For example, the sheet member is
preferably about 1 to 2 cm in length and width.
[0061] When the glass film (2) and the supporting glass (3) are
peeled off, it is preferred that the glass film laminate (1) be
immersed in water, and the peeling off be performed while applying
ultrasonic waves. With this, the amount of a force required for
peeling off the glass film (2) and the supporting glass (3) may be
reduced, so that the glass film (2) and the supporting glass (3)
are easily peeled off from each other.
[0062] FIGS. 4(a) and 4(b) are views showing a state in which a
through-hole is formed in a supporting glass: in which, 4(a) is a
plan view; and 4(b) is a cross-sectional view taken along the line
A-A.
[0063] The supporting glass (3) is preferably provided with at
least one through-hole (32). The through-hole (32) is formed at a
position at least a part thereof is covered by the glass film (2).
When the glass film (2) is peeled off from the supporting glass
(3), only the glass film (2) in the glass film laminate (1) can be
raised up from the supporting glass (3) by injecting compressed air
or inserting a pin or the like through the through-hole (32),
resulting in easily starting peeling off the glass film (2).
[0064] Onto the glass film (2) in the vicinity of the through-hole
(32), there is a possibility of an external force being applied due
to a bending stress at the starting of peeling off or the striking
of the pin or the like. In addition, a strain is likely generated
in the glass film (2) in the vicinity of the through-hole (32)
after being subjected to a heating process, owing to a difference
in heat transfer due to presence or absence of the support glass
(3) in the vicinity of the through-hole (32). Therefore, it is
preferred to form the through-hole (32) at a position corresponding
outside of the effective surface of the glass film (2). Note that,
outside of the effective surface of the glass film (2) means, for
example, an unnecessary portion that is cut and removed when the
glass film (2) is incorporated into a device, or, when forming a
film on the surface the glass film (2), a non-effective portion
that is out of a range of forming the film.
[0065] The shape of the through-hole (32) is not particularly
limited, for example, to a circular shape, a polygonal shape such
as a triangle or quadrangle. However, the circular shape is
preferred from the viewpoints of workability or prevention of crack
of the through-hole (32). Also the size of the through-hole (32) is
not particularly limited. There is exemplified a through-hole (32)
having an opening having a diameter of 1 mm to 50 mm. The
through-hole (32) is preferably formed in the vicinity of any of
the four corners when the glass film laminate (1) has a rectangular
shape in a planar view.
[0066] FIGS. 5(a) and 5(b) are views showing a state in which guide
members are provided on a supporting glass: in which 5(a) is a plan
view; and 5(b) is a cross-sectional view taken along the line
B-B.
[0067] A guide member (5) is preferably provided at outer
peripheral portion of the supporting glass (3) on the glass film
(2) side. With this, the positioning of the glass film (2) can be
easily performed when laminating the glass film (2) on the
supporting glass (3).
[0068] As shown in FIGS. 5(a) and 5(b), when the glass film
laminate (1) has a rectangular shape in a planar view, guide
members (5) are provided in parallel to two adjacent sides of the
supporting glass (3). With this, the positions of the two sides of
the glass film (2) on the supporting glass (3) are determined,
thereby being capable of more reliably performing the positioning
of the glass film (2). Further, the guide members (5) are made
lower than a thickness of the glass film (2) as shown in FIG. 5(b),
and hence, after the glass film laminate (1) being subjected to a
cleaning process, a liquid is prevented from remaining on the glass
film (2) and effectively discharged. In addition, groove (6) is
formed on the guide member (5), thereby the discharge performance
of the liquid can be further improved. It is preferred that a
plurality of the grooves (6) are formed on each of the guide
members (5).
[0069] The guide member (5) is preferably made of glass. This is
because in the case where the glass film laminate (1) is subjected
to a heating process, deterioration or wear of the guide member (5)
can be prevented. The guide members (5) may be fixed by fusion
bonding with glass frits, adhesion with resins, or the like.
[0070] In a case where a gap is formed between the guide member (5)
and the glass film (2), the gap can be infilled with filling a
resin. An ultraviolet curable resin is preferably used as the resin
to be filled. When the glass film (2) is peeled off from the
supporting glass (3), the resin can be cured by being irradiated
with ultraviolet rays. As a result, the adhesive force can be
lowered, thereby being capable of easily peeling off.
EXAMPLES
[0071] Hereinafter, the glass film laminate of the present
invention is described in detail based on examples, but the present
invention is not limited to these examples.
[0072] A transparent glass sheet having a rectangular shape and
having 250 mm in length, 250 mm in width, and 700 .mu.m in
thickness was used as a supporting glass. A glass film having 230
mm in length, 230 mm in width, and 100 .mu.m in thickness was used
as a glass film to be laminated on the supporting glass. Used for
the supporting glass and the glass film was alkali-free glass
manufactured by Nippon Electric Glass Co., Ltd. (Production name:
OA-10G, thermal expansion coefficient at 30 to 380.degree. C.:
38.times.10.sup.-7/.degree. C.). The glass formed by the overflow
down-draw method was used without polishing as it is, or by
appropriately controlling amounts of polishing and chemical
etching, to thereby control the surface roughness Ra. The surface
roughness Ra of the contacting surface of each of the supporting
glass and the glass film was measured by using an AFM (Nanoscope
III a) manufactured by Veeco Instruments under the conditions of a
scan size of 10 .mu.m, a scan rate of 1 Hz, and 512 sample lines.
The surface roughness Ra was determined from measured values within
a 10 .mu.m square measurement range. After the measurement, each of
the supporting glasses and the glass films was divided into test
groups shown in Table 1.
[0073] With respect to the supporting glasses and the glass films
thus grouped, by controlling cleaning and indoor air conditioning,
amounts of dust contained in the water and the air were adjusted,
and thus amounts of dust attaching to the contacting surfaces of
the supporting glasses and glass films were adjusted, to thereby
control the GI value. The GI value was measured by using GI7000
manufactured by Hitachi High-Tech Electronics Engineering Co.,
Ltd.
[0074] After that, in accordance with the respective divisions
shown in Table 1, the glass films were laminated on the supporting
glasses, and thus the glass film laminates of Examples 1 to 8 and
Comparative Examples 1 to 3 were obtained.
[0075] Each of the obtained glass film laminates was subjected to a
cleaning process to determine the quality of adhesive strength. As
for glass film laminates, in which the peeling off occurred due to
incursion of the water between the contacting surfaces during the
cleaning step, "x" are marked. As for a glass film laminate which
was cleaned without causing the peeling off, ".smallcircle." are
marked. As for a glass film laminate, in which the peeling off was
not occurred even being subjected to further friction cleaning with
a brush, ".circleincircle." are marked. The close contactness of
the glass film laminates was thus determined. Table 1 shows the
results.
TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4
Glass film Ra (nm) 0.2 0.5 1.0 2.0 Supporting glass Ra (nm) 0.2 0.5
1.0 2.0 Glass film 500 500 500 500 GI value (pcs/m.sup.2)
Supporting glass 500 500 500 500 GI value (pcs/m.sup.2) Result of
determination .circleincircle. .largecircle. .largecircle.
.largecircle. Example 5 Example 6 Example 7 Example 8 Glass film Ra
(nm) 0.2 0.2 0.2 0.2 Supporting glass Ra (nm) 0.5 0.5 0.5 0.5 Glass
film 100 500 800 1000 GI value (pcs/m.sup.2) Supporting glass 100
500 800 1000 GI value (pcs/m.sup.2) Result of determination
.circleincircle. .largecircle. .largecircle. .largecircle.
Comparative Comparative Comparative Example 1 Example 2 Example 3
Glass film Ra (nm) 1.0 2.5 2.5 Supporting glass Ra (nm) 2.5 1.0 2.5
Glass film 500 500 500 GI value (pcs/m.sup.2) Supporting glass 500
500 500 GI value (pcs/m.sup.2) Result of determination X X X
[0076] As shown in Table 1, in Examples 1 to 8 in which the glass
film and supporting glass have a surface roughness Ra of 2.0 nm or
less respectively, the glass film and the supporting glass have a
sufficient close contact, and hence each glass film laminate can be
cleaned without causing the peeling off. Contrary, in Comparative
Examples 1 to 3, in which any one of the glass film and the
supporting glass has a surface roughness Ra of 2.5 nm or more, as
the contacting surfaces is rough, and hence the close contact
between the glass film and the supporting glass is low, which shows
that the water to causes the peeling off entered between the
contacting surfaces of the both glasses during cleaning.
INDUSTRIAL APPLICABILITY
[0077] The present invention can be suitably used as a glass
substrate for devices such as a flat panel display including a
liquid crystal display and an OLED display and a solar cell and as
a cover glass for an OLED lighting device.
DESCRIPTION OF SYMBOLS
[0078] 1 glass film laminate [0079] 2 glass film [0080] 3
supporting glass [0081] 32 through-hole [0082] 4 step [0083] 5
guide member [0084] 6 groove
* * * * *