U.S. patent application number 11/138248 was filed with the patent office on 2006-01-19 for supporting bar for substrate cassette.
Invention is credited to Kenichi Aoyagi, Yi-Kuang Chen, Toshiyuki Takahashi, Shinichi Takemura, Daisuke Uchida.
Application Number | 20060011507 11/138248 |
Document ID | / |
Family ID | 35451148 |
Filed Date | 2006-01-19 |
United States Patent
Application |
20060011507 |
Kind Code |
A1 |
Uchida; Daisuke ; et
al. |
January 19, 2006 |
Supporting bar for substrate cassette
Abstract
A plate cassette support bar that suppresses the increase in
weight of the plate or substrate cassette that increases in size
and lessens substrate or plate cassette vibration at the time of
loading/unloading the substrates or plates to improve workability.
The substrate or plate cassette has the end support parts that
support the ends of the substrates or plates stored on both the
right and left side of the substrate loading opening and the
support bars that are fixed at the opposite side of the substrate
loading opening, that have free ends on the substrate loading
opening side, that are allotted in one line or multiple lines in
the vertical direction, and that support the substrates to be
stored between the above-mentioned end support parts of the
cassette, and which stores multiple substrates horizontally in
multiple levels in the vertical direction, the above-mentioned
support bars are formed by the carbon fiber reinforced composite
material containing 30% or more of highly elastic carbon fibers
having a tensile modulus of 490-950 GPa, and are formed preferably
into the shape of a hollow pipe, or more preferably into the shape
of a taper that the tip part side becomes narrower.
Inventors: |
Uchida; Daisuke; (Kanagawa,
JP) ; Takemura; Shinichi; (Kanagawa, JP) ;
Aoyagi; Kenichi; (Kanagawa, JP) ; Chen; Yi-Kuang;
(Taipei, TW) ; Takahashi; Toshiyuki; (Saitama,
JP) |
Correspondence
Address: |
E I DU PONT DE NEMOURS AND COMPANY;LEGAL PATENT RECORDS CENTER
BARLEY MILL PLAZA 25/1128
4417 LANCASTER PIKE
WILMINGTON
DE
19805
US
|
Family ID: |
35451148 |
Appl. No.: |
11/138248 |
Filed: |
May 26, 2005 |
Current U.S.
Class: |
206/711 |
Current CPC
Class: |
B65D 85/48 20130101;
H01L 21/67343 20130101 |
Class at
Publication: |
206/711 |
International
Class: |
B65D 85/00 20060101
B65D085/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 26, 2004 |
JP |
2004-156755 |
Claims
1. A plate cassette support bar in a plate cassette, wherein said
plate cassette accommodates a multiplicity of plates, each having a
center, in a horizontal manner and in multiple levels in the
vertical direction, said plate cassette support bar provides
support to control warping at the center of each of the plates,
said plates characterized by being formed of a carbon fiber
reinforced composite material that contains 30% or more by volume
ratio of high-elasticity carbon fiber with a tensile modulus of
490-950 GPa.
2. The plate cassette support bar disclosed in claim 1,
characterized by said plate cassette support bar having a hollow
shape.
3. The plate cassette support bar disclosed in claim 1 or 2, said
plate cassette support bar comprising a fixed end that attaches to
the plate cassette and a free end opposite the fixed end, said free
end having a tip, said plate cassette support bar characterized by
a perimeter of the said plate cassette support bar in a direction
perpendicular to a longitudinal direction of the plate cassette
support bar being smaller from its fixed end toward the tip at its
free end.
4. The plate cassette support bar disclosed in claim 3,
characterized by the perimeter at the tip being 1/3- 9/10 the
perimeter at the fixed end of the plate cassette support bar.
5. The plate cassette support bar disclosed in claim 3 or 4,
characterized by the plate cassette support bar having a hollow
square pipe shape with a taper, wherein the width of said plate
cassette support bar narrows as the tip is approached.
6. The plate cassette support bar disclosed in any of claims 1
through 5, characterized by comprising a heat-cured laminated
structure containing a pre-preg sheet in which carbon fibers
comprising high-elasticity carbon fibers of tensile modulus 490-950
GPa are unidirectionally oriented at 0.+-.5.degree. to a
longitudinal direction of the plate cassette support bar.
7. The plate cassette support bar disclosed in claim 6,
characterized by comprising a heat-cured laminated structure
wherein a pre-preg sheet having a high-elasticity carbon fibers of
tensile modulus 490-950 GPa are unidirectionally oriented at
0.+-.5.degree. to the longitudinal direction of the support bar, is
laminated on the outer layer of a pre-preg sheet in which
high-elasticity carbon fibers of tensile modulus of less than 490
GPa are unidirectionally oriented at 90.+-.5.degree. to the
longitudinal direction of the support bar, and a cross pre-preg
sheet containing reinforcing fibers is wrapped around the outermost
layer.
8. A plate cassette comprising edge support members that support
the edges of the plates, each plate having a center, said edge
support members being positioned on both a right side and a left
side of a plate feed opening, and support bars that are attached at
a side opposite the plate feed opening, the support bars having
free ends opposite thereto, disposed in a line or in a multiplicity
of lines in a vertical direction with the free ends at the plate
feed opening, and that support said plates to control warping at
the center of each of said plates, and which accommodates a
multiplicity of plates in a horizontal manner in multiple levels in
a vertical direction, wherein which plate cassette is characterized
by the support bars being the support bar disclosed in any of
claims 1 through 7.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority under 35 USC
.sctn. 119 from Japan Application No. 2004-156755, Publication No.
______ entitled SUPPORTING BAR FOR SUBSTRATE CASSETTE, filed May
26, 2004. The disclosure of which is incorporated by reference in
its entirety herein for all purposes.
FIELD OF THE INVENTION
[0002] The present invention relates to a substrate storage
cassette used in a manufacturing process of a glass substrate used
for a liquid crystal display, for example. More particularly, the
present invention relates to the central support component (support
bar) allotted in each step of a cassette.
BACKGROUND OF THE INVENTION
[0003] The conventional liquid crystal display element has been
manufactured by forming patterns, such as a picture element
electrode, wiring, etc., on one side of the liquid crystal display
element substrate, forming an orientation film by an application or
adhesion processing on it, carrying out a rubbing processing of
this orientation film so that the liquid crystal molecules are
oriented regularly to the orientation surface, subsequently pasting
two substrates for liquid crystal display elements through seal
material so that the sides on which picture element electrode,
wiring, etc., of the above-mentioned substrates for liquid crystal
display elements face each other at a uniform interval, and then
enclosing liquid crystal into the space formed between the
substrates. In the manufacturing process of such a liquid crystal
display element, multiple processing devices, such as a spatter
processing device used for forming a picture element electrode,
etc., a chemical vapor deposition device, a spin coater which
applies orientation film, and a rubbing device which performs
rubbing of the orientation film, etc., were used.
[0004] Therefore, after finishing processing of the substrate with
one processing device, in order to move the substrate to another
processing device for processing, the substrate needed to be stored
temporarily, and a box type cassette was used for this storage.
[0005] A conventional storage cassette has: a front side which is
open to insert and remove a substrate; a top side; a bottom side;
left and right sides of the storage cassette; a back side; and
substrate end support parts that project from the left and right
sides of the storage cassette towards the inside of the storage
cassette to support both right and left ends of the substrate or
plate.
[0006] Since the storage cassette structure supports only both ends
of a glass substrate, the central part of the substrate bends
greatly when a large-sized glass substrate is used. And, when a
substrate transfer fork, such as a robot performed transfer of a
substrate, there were problems because the transfer fork could not
smoothly carry the substrate because the transfer fork either
contacted the bent portion of the central part of the glass
substrate contained directly above the substrate inserted into the
storage cassette, or the substrate was scratched. Moreover, since
the storage amount to a cassette fell sharply when the interval of
the substrates is expanded in order to avoid contact of glass
substrates, there was a problem of causing decline in production
efficiency.
[0007] The following disclosures may be relevant to various aspects
of the present invention and may be briefly summarized as
follows:
[0008] In order to reduce this warping of the glass substrate
central part, the Japan Unexamined Patent Publication Heisei
9-36219 proposed to lessen the warping of the central part by
increasing the length of the shelf pieces that jut out from both
the right and left sides of the loading opening of the storage
cassette over the length of conventional shelf pieces. However,
when the shelf pieces jutting out are lengthened in this manner, in
order to make a substrate transfer fork not contact the shelf
pieces, the width of the fork must be reduced. In addition,
although the Heisei 9-36219 application indicates the use of carbon
fibers as conductive material, it is not used as a strengthening
fiber.
[0009] On the other hand, in order to support the center of a
substrate in addition to supporting both ends of the stored glass
substrate, it is proposed to prepare a central support part (e.g.,
support bar) projecting from aforementioned back side of the
storage cassette towards the front of the storage cassette. With
this support bar, it has been supposed that the maximum warping at
the substrate central part decreases and contact between the
substrates of the steps (or the left and right shelf pieces) above
and below can be prevented. See the following publications: Japan
Unexamined Patent Publication 2000-7148; 2000-142876 and
2003-341784.
[0010] However, the trend of making lighter and larger the
substrate for liquid crystal display elements has advanced further,
and in terms of size, glass substrate of a size with which a length
of one side amounts to 2000 mm, and the thickness is getting
smaller from 0.7 mm to 0.5 mm. For this reason, with the
conventional support bar using metals with low flexural rigidity,
such as aluminum, the problem that it cannot suppress the warping
at the glass substrate central part newly occurred.
[0011] In addition, as a result of elongating the support bar along
with the trend of enlarging the glass substrate, the bending
vibration generated at the time of loading and unloading the glass
substrates from the cassette is less likely to decrease, and the
manufacture line speed is reduced. Furthermore, since the material
(mainly metal material, such as iron, stainless steel, aluminum,
etc.) used for conventional support bars have a large density, it
also caused the problem of a steep increase in weight of the
storage cassette.
[0012] In view of the above problems, it is desirable for the
present invention to offer a support bar, which can prevent contact
between the horizontal glass substrates or plates inserted in the
steps (or the left and right shelf pieces) above and below each
substrate or plate in vertical succession. It is desirable that the
substrates or plates of the present invention prevent contact, even
at the time of storing a large-sized glass substrate, while it does
not cause a steep increase in the whole storage cassette weight,
and that it further increases the manufacture line speed by the
excellent vibration dampening properties and improves production
efficiency.
SUMMARY OF THE INVENTION
[0013] Briefly stated, and in accordance with one aspect of the
present invention, there is provided a plate cassette support bar
in a plate cassette, wherein said plate cassette accommodates a
multiplicity of plates, each having a center, in a horizontal
manner and in multiple levels in the vertical direction, said plate
cassette support bar provides support to control warping at the
center of each of the plates, said plates characterized by being
formed of a carbon fiber reinforced composite material that
contains 30% or more by volume ratio of high-elasticity carbon
fiber with a tensile modulus of 490-950 GPa.
[0014] Pursuant to another aspect of the present invention, there
is provided a plate cassette support bar disclosed above,
characterized by said plate cassette support bar having a hollow
shape.
[0015] Pursuant to another aspect of the present invention, there
is provided a plate cassette support bar disclosed in the preceding
paragraphs, said plate cassette support bar comprising a fixed end
that attaches to the plate cassette and a free end opposite the
fixed end, said free end having a tip, said plate cassette support
bar characterized by a perimeter of the said plate cassette support
bar in a direction perpendicular to a longitudinal direction of the
plate cassette support bar being smaller from its fixed end toward
the tip at its free end.
[0016] Pursuant to another aspect of the present invention, there
is provided a plate cassette support bar disclosed the preceding
paragraph, characterized by the perimeter at the tip being 1/3-
9/10 the perimeter at the fixed end of the plate cassette support
bar.
[0017] Pursuant to another aspect of the present invention, there
is provided a plate cassette support bar disclosed in the preceding
paragraphs, characterized by the plate cassette support bar having
a hollow square pipe shape with a taper, wherein the width of said
plate cassette support bar narrows as the tip is approached.
[0018] Pursuant to another aspect of the present invention, there
is provided a plate cassette support bar disclosed in the preceding
paragraphs, characterized by comprising a heat-cured laminated
structure containing a pre-preg sheet in which carbon fibers
comprising high-elasticity carbon fibers of tensile modulus 490-950
GPa are unidirectionally oriented at 0.+-.5.degree. to a
longitudinal direction of the plate cassette support bar.
[0019] Pursuant to another aspect of the present invention, there
is provided a plate cassette support bar disclosed in the preceding
paragraphs, characterized by comprising a heat-cured laminated
structure wherein a pre-preg sheet having a high-elasticity carbon
fibers of tensile modulus 490-950 GPa are unidirectionally oriented
at 0.+-.5.degree. to the longitudinal direction of the support bar,
is laminated on the outer layer of a pre-preg sheet in which
high-elasticity carbon fibers of tensile modulus of less than 490
GPa are unidirectionally oriented at 90.+-.5.degree. to the
longitudinal direction of the support bar, and a cross pre-preg
sheet containing reinforcing fibers is wrapped around the outermost
layer.
[0020] Pursuant to another aspect of the present invention, there
is provided a plate cassette comprising edge support members that
support the edges of the plates, each plate having a center, said
edge support members being positioned on both a right side and a
left side of a plate feed opening, and support bars that are
attached at a side opposite the plate feed opening, the support
bars having free ends opposite thereto, disposed in a line or in a
multiplicity of lines in a vertical direction with the free ends at
the plate feed opening, and that support said plates to control
warping at the center of each of said plates, and which
accommodates a multiplicity of plates in a horizontal manner in
multiple levels in a vertical direction, wherein which plate
cassette is characterized by the support bars being the support bar
disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The invention will be more fully understood from the
following detailed description, taken in connection with the
accompanying drawings, in which:
[0022] FIG. 1 is an outline perspective diagram showing an example
of the substrate cassette using the support bar of the present
invention.
[0023] FIG. 2 is a perspective view showing the attachment of the
support bar to the support component.
[0024] FIGS. 3A-3I show perspective views of examples of the form
of the support bar of the present invention.
[0025] FIG. 4 shows a perspective view of an example of a hollow
structure (e.g., a hollow circular pipe).
[0026] FIGS. 5A-5C show views of an example of a hollow support bar
of the present invention. FIG. 5A is a perspective view, FIG. 5B is
a plan view and FIG. 5C is a side view.
[0027] FIGS. 6A-6C show views of an example of a hollow support bar
of the present invention. FIG. 6A is a perspective view, FIG. 6B is
a plan view and FIG. 6C is a side view.
[0028] FIG. 7 is a graphical depiction showing the free oscillating
attenuation waveform in the evaluation of the vibration dampening
properties. The graph shows amplitude vs. time.
[0029] FIG. 8 is a graphical depiction showing the vibration
dampening properties of the hollow support bar of this invention
shown in Execution Example 1. The graph shows bending distortion
vs. lapsed time.
[0030] FIG. 9 is a graphical depiction showing the vibration
dampening properties of the hollow support bar of this invention
shown in Comparison Example 1. The graph shows bending distortion
vs. lapsed time.
[0031] FIG. 10 is a graphical depiction showing the vibration
dampening properties of a solid support bar shown in Comparison
Example 2. The graph shows bending distortion vs. lapsed time.
[0032] FIG. 11 is a graphical depiction showing the logarithmic
dampening of the support bars of Execution Example 1 and Comparison
Examples 1 and 2. The graph shows logarithmic dampening vs. bending
distortion.
[0033] While the present invention will be described in connection
with a preferred embodiment thereof, it will be understood that it
is not intended to limit the invention to that embodiment. On the
contrary, it is intended to cover all alternatives, modifications,
and equivalents as may be included within the spirit and scope of
the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
[0034] In the present invention, by constituting the support bar
from carbon fiber reinforced composite material, which is
lightweight and has high rigidity, there is only a small increase
in weight even for a large substrate cassette. The support bar of
the present invention is composed of carbon fiber reinforced
composite material, which is lightweight and an excellent vibration
dampening properties as well as high flexural rigidity.
[0035] By making a support bar into a hollow pipe structure,
deflection or warping of the support bar from its own weight is
suppressed and it is an excellent way to make the support bar
lightweight. In addition, by decreasing the perimeter of the
support bar from the immobilized end to the tip, a support bar
being better or more improved in vibration dampening properties can
be obtained, and since the vibration of the carried-in or inserted
substrate is decreased in a short time, the substrate loading speed
improves and working efficiency improves remarkably.
[0036] Reference is now made to the drawings for a detailed
description of the present invention.
[0037] FIG. 1 shows an outline perspective diagram serving as an
example of a glass substrate cassette 1 which has the support bar
of this invention, and carrying in and taking out of the substrate
4, such as a glass substrate, are performed from the direction of
Arrow A of this figure.
[0038] The shelf pieces 2 used as the end support parts to support
the ends of the substrates to be stored are prepared on both the
right and left sides of the substrate loading opening, the support
bars 3 which have the immobilized end fixed to the opposite side of
the substrate loading opening. The component 5 is prepared in one
line in the vertical direction as shown in the figure, and
suppresses the deflection or warping at the central part of the
substrates or plates and maintains the substrates leveled in the
storage cassette.
[0039] Although this figure shows a glass substrate cassette in
which the support bars 3 of one line in the vertical direction are
prepared almost at the center of the opposite side of the substrate
loading opening, it is not limited to this, and it can be in
multiple lines as long as the warping of the central part of the
substrate is suppressed.
[0040] Although the support bars 3 are fixed in one line in the
vertical direction at a predetermined pitch to the support
component 5, the immobilization method is not specified. However,
many known methods of immobilizing the support bars can be applied.
For example, FIG. 2 shows a well known method in which multiple
slots 51 into which the support bars 3 can be inserted are prepared
at a predetermined pitch on a side of the support component 5, the
support bars 3 are inserted therein and are further immobilized by
a means, such as bolt bundle.
[0041] In the present invention, the support bar 3 is constituted
from carbon fiber reinforced composite material (CFRP) using carbon
fibers having a specific tensile modulus in order to make the
support bar have excellent properties such as being lightweight in
nature, having flexural rigidity, heat resistance, etc. In the
present invention, 30% or more of the highly elastic carbon fibers
have a tensile modulus of 490-950 GPa used by the volume ratio as
carbon fibers. Sufficient rigidity is not acquired when the volume
ratio is less than 30%, and the component having high vibration
dampening properties is not obtained. It is preferable that the
volume ratio of carbon fibers used in the present invention is 40%
or more.
[0042] Additionally, it is good to use all strengthening fibers
made of highly elastic carbon fibers, or some may be constituted
from other strengthening fibers, such as carbon fibers having a
tensile modulus of less than 490 GPa, glass fibers, aramid fibers,
silicon carbide, fibers, and other well-known strengthening fibers.
A preferable result is brought in many cases when, for example, the
highly elastic carbon fibers are limited to 90% by the volume ratio
and used in combination with other strengthening fibers, especially
the carbon fibers having a tensile modulus of less than 490 GPa, in
the remainder.
[0043] It is not necessary for such support bars 3 to have the
shape of a square pillar as shown in FIG. 1, and it may have
various pillar-shaped structures, for example, as shown in FIG. 3,
the cross-section form of the pillar-shaped structure may be a
triangle (FIG. 3(a)), a trapezoid (FIG. 3 (b)), a polygon (FIG.
3(c)), a circle (FIG. 3(d)), a semicircle (FIG. 3 (e)), the shape
of a letter C (FIG. 3 (f)), the shape of an upside down letter U
(FIG. 3(g)), the shape of a letter T (FIG. 3 (h)), the shape of a
letter I (FIG. 3 (i)), etc. In addition, although the support bar 3
may have a pure structure of the carbon fiber reinforced composite
material or a solid structure, such as a skin core structure which
uses other material as the core layer and the carbon fiber
reinforced composite material concerning this invention as the skin
layer, etc., it is desirable to have a hollow structure emasculated
in the center in the above-mentioned cross-section for a
lightweight support bar 3.
[0044] For example, square pillar pipes, etc. shown in FIGS. 5 and
6 are made into hollow circular pipes as the circular hollow
structure as shown in FIG. 3 (d) and FIG. 4. The length of the
support bars is determined suitably according to the size of the
substrates to be stored, since it is sufficient if they can support
the substrates so that the warping of the central part of the
substrates to be stored is suppressed, and in this invention, the
longer the length of the support bars is, the more remarkable its
effect becomes (i.e., the less likely the warping of the central
part).
[0045] The present invention is particularly useful when the length
of the support bars is 500 mm or more. The width of the support
bars is not specified. It is sufficient to secure the minimum width
of the support bar as long as it is sufficient to provide the
strength and the flexural rigidity required in order to suppress
the warping of the central part of the substrates to be stored are
maintained according to how to combine the materials to be used.
Additionally, the height can be suitably set so that the minimum
strength and flexural rigidity can be secured in relation to the
width in the range of the storage pitch of the substrates.
[0046] In addition, in order to acquire a high vibration dampening
properties, it is desirable to have the structure where the
perimeter of the direction that intersects perpendicularly with its
longitudinal direction becomes smaller as the tip part that is a
free end as opposed to the immobilized end of the support bar.
Especially, the combination with hollow structure is a desirable
mode.
[0047] When reducing the perimeter towards the tip part of the
support bar in this way, it is desirable for the perimeter of the
tip part is 1/3 or more, more preferably 1/2 or more, of the
perimeter of the side of the immobilized end. Although effect will
be taken on the vibration dampening properties if the perimeter is
made smaller, even a little as compared with that of having the
same perimeter, it is desirable to make it 9/10 or less, more
preferably 3/5 or less.
[0048] Here, "the longitudinal direction" is the direction of a
line that connects the cross-sectional center of gravity (G1) by
the immobilized side end of a hollow shape (the support component 5
side) and the cross-sectional center of gravity (G2) of the tip
part as shown in FIG. 5. In order to make the perimeter smaller
towards the tip part, for example, in the case of an angle pipe
form, when the width and height of the immobilized end side are
expressed as H1 and T1 and the width and height of the tip part as
H2 and T2, respectively, a taper form in which only the width
narrows towards the tip (H1>H2, T1=T2) shown in FIG. 5((A) a
perspective diagram, (B) a top view, (C) a side view), a taper form
in which only the thickness narrows towards the tip (H1=H2,
T1>T2), shown in FIG. 6 ((A) a perspective diagram, (B) top
view, (C) a side view), a taper form in which both the width and
height narrow towards the tip (H1>H2, T1>T2), etc. are
mentioned.
[0049] In addition, as for the mode of making the perimeter smaller
towards the tip direction, it is not limited to the mode of
decreasing it evenly from the immobilized end side to the tip part
shown in FIGS. 5 and 6, but various modes. For example, the mode by
which the perimeter is not changed at the portion around the
immobilized end and it is made gradually smaller from that point on
to the free end, or that by which the perimeter is made to decrease
up to the midpoint of the longitudinal direction and the rest is
made constant from that point on, etc. are other such modes.
[0050] In addition, the tip part may be in an open state as shown
in FIGS. 5 and 6, or the tip part may be in a closed state by
bending the prepreg sheet at the time of manufacturing the hollow
component mentioned herein. Or, a cap made of an elastic component,
such as rubber, etc., may be inserted to the tip part of an open
state.
[0051] The manufacturing method of the support bar of this
invention is explained hereafter and especially the manufacturing
method of the support bar of a hollow structure having a tapered
shape as shown in FIGS. 5 and 6, but it can be easily understood by
the industry concerned that the method explained below may be
changed suitably to manufacture a support bar of other forms.
[0052] For example, a removable core and an original-form prepreg
sheet are first prepared in the preparation process. The removable
core is formed into a tapered shape to correspond to the shape or
form of the interior of the support bar. The material of the
removable core has a certain amount of rigidity in order to
function as the interior support mandrel at the time of laminating
the prepreg sheet, has the characteristic that the removable core
does not change its shape by the temperature lower than the heating
temperature in the heating process in order to function as the
interior mold mandrel at the time of forming the support bar, and
can be easily taken out from the CFRP component after molding. From
this viewpoint, as the material of the removable core, for example,
metals, such as aluminum, iron, stainless steel, etc., MC nylon
resin, polyimide resin, etc. are suitable. Since the thermal
expansion rate of the above-mentioned removable core materials
(e.g., metal, resin, etc.) is larger than CFRP, the removable core
contracts by cooling after heating, and the removable core is easy
to take out from the interior of the molded CFRP component.
[0053] In addition, mold release material may be applied to the
surface of the removable core if needed. As the mold release
material, it may be applied by any method, such as application of a
chemical (for example, a surface-active agent etc.) by spraying,
use of a mold release sheet, such as a Teflon.RTM. sheet, etc.
[0054] In addition, the thermal non-deforming properties of the
removable core at the above-mentioned predetermined temperature
means that it has the properties with which it hardly changes its
shape at the heating temperature in the below-mentioned heating
process. By hardly changing its shape at the above-mentioned
heating temperature, it means that the material of the core
material does not melt or that curve, warping, twist, wrinkle,
fold, etc. are not caused to the component of the core material
under the heating conditions mentioned herein. In addition, the
above-mentioned predetermined temperature means the temperature of
about 100-190 degrees C. or more, corresponding to the molding
temperature of the matrix resin of the original-form prepreg sheet
mentioned later.
[0055] For example, the removable core for creating the support bar
of FIG. 5 is a mandrel of which the cross-section has the shape of
an oblong rectangle-like square and which is processed into a taper
shape with which the width narrows towards the tip. In addition,
for the removable core for producing the support bar component of
FIG. 5, the height becomes smaller towards the tip.
[0056] The original-form prepreg sheet comprises the matrix resin
impregnated into a sheet made of carbon fibers, and is an
un-hardened sheet. For example, it is desirable to use the highly
elastic carbon fiber prepreg sheet having a tensile modulus of
490-950 GPa as the base for the multiple prepreg sheets to be
laminated, and to use carbon fiber prepreg sheet having a tensile
modulus of less than 490 GPa for the remainder.
[0057] In addition, the prepreg sheet containing the
above-mentioned glass fiber or other fibers may be added in some
part within the limitation, which does not spoil the support
performance as support bar component. As the matrix resin,
thermosetting resin, such as epoxy resin, phenol resin, cyanate
resin, unsaturated polyester resin, polyimide resin, bismaleimide
resin, etc., are used. In this case, any material, which can bear a
high temperature/high moisture environment, such as vulcanized
rubber, is preferred.
[0058] In addition, for the above-mentioned thermosetting resin,
fine particles consisting of rubber or resin may be added to the
thermosetting resin for the purpose of giving shock resistance and
toughness, or a thermoplastic resin is dissolved in the
thermosetting resin may be used.
[0059] As the sorts of carbon fibers, although there are those of
the PAN (i.e., polyacryloniprile) system of less than 490 GPa and
those of the pitch system of 490-950 GPa, by this invention, both
of these are used in combination. In this case, those of the pitch
system have the feature that the elasticity is high and those of
the PAN system have the feature that tensile strength is high.
[0060] In addition, as the original-form prepreg sheet, there are
unidirectional sheets in which the strengthening fibers are
oriented all in the same direction and cross sheets, such as plain
woven fabric, twill fabric, satin fabric, 3-axis fabric, etc. As
for the highly elastic carbon fiber prepreg sheet of 490-950 GPa,
it is preferable to use a unidirectional sheet. As for the
original-form prepreg sheet, it is preferable to prepare the sheet
in various types by making the sort of the strengthening fibers
differ, making the use ratio of the strengthening fibers to matrix
resin differ, or making the orientation state of the strengthening
fibers differ, and to select multiple original-form prepreg sheets
to be used so that the CFRP component with the optimal flexural
rigidity is formed according to the glass substrate to hold.
[0061] In addition, the pieces of prepreg sheet of a predetermined
size are similarly formed about all the original-form prepreg
sheets selected above. Next, laminating pasting of the pieces of
prepreg sheet is carried out in each side of the core material
(laminating process).
[0062] The pieces of prepreg sheet are non-hardened, and since it
has a certain amount of adhesive power, pasting is carried out only
by piling up the sheets one by one on the removable core to which
mold release processing is performed. In this case, adhesion
lamination is carried out by making it adhere to the lower layer
film or sheet while applying heat with an iron etc until it becomes
the desired thickness (for example, about 1-7 mm). The desired
thickness at this time is preferably slightly thicker than the
required thickness of the robot hand that loads and unloads the
substrates into the substrate cassette with the amount of the
volume reduction at the time of a prepreg sheet carrying out
heating hardening foreseen. In the lamination of prepreg sheets,
unidirectional sheets in which the carbon fibers are oriented with
a .about.right angle (90.+-.5.degree.) to the longitudinal
direction (henceforth "90.degree. orientation") are laminated in
multiple levels at the innermost part (that is, the lowest layer),
and unidirectional sheets oriented in .about.parallel
(0.+-.5.degree.) to the longitudinal direction (henceforth
"0.degree. orientation") are laminated in multiple levels on top of
it.
[0063] In this case, in addition to the above-mentioned sheets,
unidirectional sheets oriented in the slanted direction
(45.+-.15.degree. or 135.+-.15.degree.) (henceforth "45.degree. or
135.degree. orientation") or cross prepreg sheets oriented in two
directions of 45.degree. and 135.degree., etc., may be laminated in
combination.
[0064] In this case, 0.degree. orientation sheets have the warping
prevention properties and vibration dampening properties of the
longitudinal direction. 90.degree. orientation sheets have the
effect of controlling collapse of the hollow structure.
Furthermore, by combining 45.degree. orientation sheets and
135.degree. orientation sheets, twist rigidity and twist vibration
dampening properties are additionally improved. As for the cross
sheets, it has the effect based on the above-mentioned combination
of unidirectional sheets.
[0065] In addition, as a laminating order, it is preferable for the
ease of taking out the removable core to have 90.degree.
orientation sheet in the lowest layer (the innermost side).
[0066] That is, because the pipe-like CFRP support bar does not
contract much when thermal hardening is carried out, the
strengthening fibers parallel to the perimeter of the removable
core by constituting the inner side of the pipe-like CFRP support
bar with 90.degree. orientation sheets. This is because the
contraction rate in the non-fiber orientation direction is lower
than the contraction rate in the fiber arrangement direction with
regard to the contraction rate as a sheet due to the carbon fibers
having a lower thermal contraction rate than the matrix resin.
[0067] In addition, since the sheets that are laminated in the
upper layers (that is, the outer sheets) have a higher contribution
rate to the quality of the support bar (that is, flexural rigidity,
etc.), it is desirable to laminate the 0.degree. orientation sheets
in the layer upper than the 90.degree. orientation sheets from a
viewpoint of warping prevention properties. The combination and the
laminating order of the prepreg sheets to be used are determined
taking this point into consideration.
[0068] In the present invention, it is preferable to use the highly
elastic carbon fiber prepreg sheets of 490-950 GPa, particularly
for the 0.degree. orientation sheets.
[0069] By carrying out laminating pasting of the prepreg sheets to
all the sides of the core material in this way, the laminated
component in the state where the laminated object of the prepreg
sheets was formed on the perimeter surface of the removable core is
formed.
[0070] Then, the perimeter of this laminated component is covered
by winding one roll or a few rolls of the cross prepreg sheet
(covering process). In addition, the cross prepreg sheet is an
non-hardened sheet in which the above-mentioned matrix resin was
made to impregnate into the strengthening fibers woven in multiple
directions, and as the strengthening fibers, fabric-like carbon
fibers, glass fibers, aramid fibers, silicon carbide fibers, etc.
are desirable. In addition, a sheet having high flexibility and
adhesiveness is desirable so that it adheres tightly to the
laminated component and covers it.
[0071] After this covering process, exterior mold forms are pushed
onto it from all four directions, the non-hardened component of
this state is out into a vacuum packed, and by heating, and the
support bar component of this invention is formed.
[0072] The heating conditions in this case is that it is heated by
the rate of 2-10.degree. C./min from room temperature, it is
maintained for about 10-180 minutes at about 100-190.degree. C.,
heating is stopped after that, and it is cooled by natural cooling
and it is returned to normal temperature.
[0073] Since any prepreg sheet contains thermosetting resin, it
hardens into a state where they are pasted to each other at the
surface or the edge of each sheet. In addition, putting the
non-hardened component into a vacuum packing serves the purpose of
sucking out the air bubbles between the sheets etc. produced at the
laminating process, and the purpose of applying the external
pressure (that is, atmospheric pressure) mostly equally to the
non-hardened component.
[0074] In addition, the external pressure of the specific direction
may be applied to the non-hardened component. For example, by
putting pressure from the top by a weight etc. in a way that a gap
is not produced between the exterior mold form and the thickness
setting board, the flatness of the top side of the CFRP support bar
3 (that is, the substrate support side) improves and the size
(especially thickness) accuracy of the CFRP support bar 3 becomes
high, and by putting pressure in the direction which the connection
interfaces are pushed against each other by a vise etc., the
connection at the edge of the prepreg sheets improves.
[0075] Then, the core material is taken out (removing process). The
CFRP support bar 3 of hollow structure is formed by this. According
to this embodiment of the present invention, since the CFRP support
bars 3 are constituted not as a solid object but as a hollow
structured object, lightweight support bars can be attained.
[0076] Therefore, generation of warping or vibration at the tip of
the support bar due to the self weight or the load of the
substrates to be loaded can be prevented, and the support accuracy
of the substrates and the loading/unloading nature can be
increased.
[0077] According to this embodiment of the present invention, since
the removable core bears two functions as the interior support
mandrel at the time of laminating the prepreg sheets and as the
interior mold mandrel at the time of carrying out heating forming
the support bar 3, the formation of the CFRP board (i.e.,
laminating of the prepreg sheets) and the formation of the CFRP
support bar (i.e., mutual connection between the prepreg sheets and
the adjacent wall parts) can be performed simultaneously.
[0078] In addition, since the perimeter surface was covered with
the cross prepreg sheets, when post-processing operations such as
cutting, opening slot, etc., is performed, fuzz and fraying
produced at the processing part can be prevented in the present
invention.
[0079] By this, while processability improves, there is no fear of
damaging precision substrates, such as a substrate for liquid
crystal displays, a substrate for plasma displays, a silicon wafer,
etc., and it also has the advantage that there is little generation
of dust, etc.
[0080] Additionally, there are other advantages that a level
difference, etc., produced at the connection part of the prepreg
sheet edge are covered to improve the appearance and that the
connection parts of the prepreg sheets are reinforced, by covering
by the cross prepreg sheet.
[0081] In addition, although the above-mentioned explanation
explained the method of manufacturing the support bar by combining
pieces of multiple prepreg sheets as the manufacturing method, the
present invention is not so limited. For example, the method of
winding a long prepreg sheet around the perimeter surface of the
core material and laminating, etc., is also possible.
[0082] When manufacturing the pipe type support bar, which has a
circular, hollow cross-section shown in FIG. 4, the following
procedures are performed.
[0083] The shape of the circular cross-section, which has a taper,
is used as the shape of the removable core of the support bar. That
is, the diameter is made larger on the side that corresponds to the
immobilized end of the CFRP support bar, and the diameter is made
smaller on the side that corresponds to the free end.
[0084] As for the length of the mandrel, it is desirable to make it
a little longer than the length of the support bar. Metal, such as
aluminum, iron, and stainless steel, can be used as the material of
the mandrel. As the prepreg sheets, 0.degree. orientation sheets
and 90.degree. orientation sheets are used. 45.degree. orientation
sheets and 135.degree. orientation sheets can also be added.
[0085] The prepreg sheets are cut out in advance as follows:
[0086] The prepreg sheets to be wound around the circular mandrel
usually have a trapezoid form. When the number of lamination of the
prepreg sheet to the removable core at the free end and at the
immobilized end are made the same, the upper bottom and the lower
bottom of the trapezoid have the length computed by (the
circumference of the free end).times.(the number of times of
laminating) and (the circumference of the immobilized
end).times.(the number of times of laminating).
[0087] Additionally, the height of the trapezoid is about the same
as the length of the CFRP support bar. When the number of times of
laminating the prepreg sheet to the removable core differs between
the free end and the immobilized end, by the same calculation
method as the case where the above-mentioned numbers of times of
laminating are the same number, the lengths of the upper bottom and
the lower bottom of the trapezoid can be computed, and the prepreg
sheet can be cut out.
[0088] In the case of the 0.degree. orientation sheet, the
direction of the height of the trapezoid form becomes almost
parallel to the orientation direction of the strengthening
fibers.
[0089] On the other hand, with the 90.degree. orientation sheet,
the upper bottom or the lower bottom of the trapezoid becomes
almost parallel to the orientation direction of the strengthening
fibers.
[0090] It is preferable in an embodiment of the present invention
to have the 90.degree. orientation sheet as the innermost layer,
and to position the 0.degree. orientation sheet on the outside
about the laminating order of the prepreg. This is for considering
that the mandrel can be easily taken out after formation by
surrounding the innermost side of the hollow circular pipe, i.e.,
the outside of the mandrel, by the 90.degree. orientation sheet
having a small thermal contraction rate so that the hollow circular
pipe does not contract in the direction of the circumference at the
time of thermal hardening.
[0091] After winding the predetermined prepreg on the removable
core, tapes that contracts by heating, such as a polypropylene tape
and a tape made of PET, are wound from the outside to fix prepreg,
and overheating hardening is carried out in oven.
[0092] The heating conditions is that it is heated by the rate of
2-10 degrees C./min from room temperature, it is maintained for
about 10-180 minutes at about 100-190 degrees C., heating is
stopped after that, and it is cooled by natural cooling and it is
returned to normal temperature, and by taking out the removable
core after this, a hollow circular pipe type CFRP support bar is
obtained.
[0093] Although the above explanation explained the example about
the CFRP support bar 3 using the carbon fiber reinforced composite
material, which contains highly elastic carbon fibers, about other
components, which constitute a substrate cassette, conventionally
well-known things can be used.
[0094] Furthermore, it is also possible to attain a lightweight and
rigid substrate cassette, simultaneously, by constituting the shelf
pieces 2 of the end support parts or the frame on the bottom side
and the frame on the ceiling side, and the frame on the back side
which serves as the opposite side of the substrate loading opening,
etc., similarly from the carbon fiber reinforced composite
material.
[0095] Although each shelf piece 2 of these end support parts is
made into the shape of a broad board in FIG. 1, it is also
possible, for example, to allot multiple shelf pieces 2 having a
width about the same as the support bar 3 to both the right and
left sides of the substrate loading opening at predetermined
intervals, or to regard two lines or three lines as one unit and to
allot each unit at predetermined intervals as shown in FIG. 1.
EXECUTION EXAMPLES
[0096] Hereafter, although this invention is concretely explained
with reference to the execution examples, this invention is not
limited only to these execution examples.
Execution Example 1
[0097] After preparing a trapezoidal aluminum removable core with a
height of 6.9 mm, a width of 54.9 mm in a fixed end, and its width
of 24.9 mm in a tip part as a removable core, the prepreg sheet B
in which pitch system carbon fibers with its tensile elasticity of
240 GPa was oriented at 90 degrees in the longitudinal direction of
the removable core, the prepreg sheet A in which pitch system
carbon fibers with its tensile elasticity of 800 GPa was oriented
at 0 degrees in the longitudinal direction of the removable core,
and a cross prepreg sheet C which was oriented at 0 degrees and 90
degrees for the outer layer were laminated to the removable core in
this order in the numbers listed in the Table 1 and were hardened
by heat. After it was hardened, the removable core was taken out,
and then a support bar in the shape of a hollow trapezoid with a
taper with its width of 60 mm in a fixed end, its width of 30 mm in
a tip part, its height of 12 mm, its wall thickness of 2.55 mm, and
its length of 1000 mm was obtained. TABLE-US-00001 TABLE 1
Laminated Total Direction of number of thick- Thickness laminating
sheets ness Prepreg type (mm/sheet) (degree) (sheet) (mm) Cross
prepreg sheet C 0.25 0/90 1 0.25 Prepreg sheet A 0.22 0 5 1.1
Prepreg sheet B 0.20 90 6 1.2 The core material 6.9 -- -- 6.9
Prepreg sheet B 0.20 90 6 1.2 Prepreg sheet A 0.22 0 5 1.1 Cross
prepreg sheet C 0.25 0/90 1 0.25 Total 24 12.0
Comparison Example 1
[0098] After preparing an aluminum removable core with its
thickness of 7.1 mm and its width of 55.1 mm as a the core
material, the prepreg sheet B in which pitch system carbon fibers
with its tensile elasticity of 240 GPa was oriented at 90 degree in
the longitudinal direction of the removable core. The prepreg sheet
B' in which pitch system carbon fibers with its tensile elasticity
of 240 GPa was oriented at 0 degree in the longitudinal direction
of the removable core, and a cross prepreg sheet C which was
oriented at 0 degree and 90 degree for the outer layer were
laminated to the removable core in this order in the numbers listed
in the Table 2 and were hardened by heat, and the removable core
was taken out, a hollow CFRP support bar in the shape of a hollow
trapezoid with its width of 60 mm in a fixed end, its width of 60
mm in a tip part, its height of 12 mm, its thickness of 2.45 mm,
and its length of 1000 mm was obtained. TABLE-US-00002 TABLE 2
Laminated Total Direction of number of thick- Thickness laminating
sheets ness Prepreg type (mm/sheet) (degree) (sheet) (mm) Cross
prepreg sheet C 0.25 0/90 1 0.25 Prepreg sheet B' 0.20 0 9 1.8
Prepreg sheet B 0.20 90 2 0.4 The core material 7.1 -- -- 7.1
Prepreg sheet B 0.20 90 2 0.4 Prepreg sheet B' 0.20 0 9 1.8 Cross
prepreg sheet C 0.25 0/90 1 0.25 Total 24 12.0
Comparison Example 2
[0099] After laminating the prepreg sheet B' and the cross prepreg
sheet C to the above-mentioned laminated product of the prepreg
sheet B without using a the removable core and hardening it with
heat, a solid CFRP support bar with its width of 60 mm, its height
of 12 mm, and its length of 1000 mm was obtained. The lamination of
each prepreg sheet was as in the following table 3. TABLE-US-00003
TABLE 3 Laminated Total Direction of number of thick- Thickness
laminating sheets ness Prepreg type (mm/sheet) (degree) (sheet)
(mm) Cross prepreg sheet C 0.25 0/90 1 0.25 Prepreg sheet B 0.20 0
22 4.4 Prepreg sheet B 0.20 90 13 2.6 Prepreg sheet B 0.20 0 22 4.4
Cross prepreg sheet C 0.25 0/90 1 0.25 Total 59 12.0
[0100] The measurement and the evaluation on the decrease table
characteristic of oscillating of the support bars obtained in the
execution Example 1 and the comparison Example 1 and 2 were
performed according to the following method:
[0101] The support bar was pinched at a point, which was 150 mm
from one end with a jig for fixation, and was maintained
horizontally in the state of cantilever.
[0102] Strain gages were prepared at the 50 mm point in the
longitudinal direction from the fixed part, or, at the top and
bottom sides of the fixed part, which were about 200 mm from the
end of support bar.
[0103] After the initial flexure was given to the support bar by
hanging a weight with its mass of 5 kg at the end of the free
vibration side of the bar, and the support bar was vibrated by
cutting the wires that was used to hang, the bending vibration
dampening properties of the support bar was measured by measuring
the bend and the strain in the decrease table of free
oscillating.
[0104] The bend and the strain were measured for 10 seconds, and
while calculating the frequency of vibration of the normal mode of
the support bar from the obtained free oscillating attenuation
waveform (FIG. 7), the logarithmic dampening (.DELTA.) was also
calculated by the following formula (1).
[0105] In FIG. 7 and the following formula (1), T represents the
time one cycle took, Xn represents initial oscillating amplitude
intensity, Xn represents the oscillating amplitude intensity of the
time nT, and n represents the number of amplitude. Formula .times.
.times. 1 .DELTA. = 1 n .times. ln .times. x 0 x n ( 1 )
##EQU1##
[0106] The results are shown in the following Table 4 and the
drawings, respectively. TABLE-US-00004 TABLE 4 Execution Comparison
Comparison Example 1 Example 1 Example 2 Mass (kg) 0.48 0.6 1.6
Peculiar pitch (Hz) 38.2 18.6 16.4 Bending vibration dampening
property Logarithmic Line a Line b Line c dampening: FIG. 11
[0107] According to the above-mentioned results, the support bar
produced by the method of this invention has high frequency of
vibration of the normal mode and is excellent in its vibration
dampening properties.
[0108] Consequently, since the vibration of the support can be
canceled in a very short time, it is possible to improve the
working efficiency.
[0109] In addition, it is possible to further lower the self weight
by making it into a taper form, and especially when it is necessary
to orientate many support bars in many steps, it becomes clear that
the effect for making the substrate cassette lighter is more
compared to that when making the structure in which the inside is
hollow.
[0110] It is, therefore, apparent that there has been provided in
accordance with the present invention, a support bar that fully
satisfies the aims and advantages hereinbefore set forth. While
this invention has been described in conjunction with a specific
embodiment thereof, it is evident that many alternatives,
modifications, and variations will be apparent to those skilled in
the art. Accordingly, it is intended to embrace all such
alternatives, modifications and variations that fall within the
spirit and broad scope of the appended claims.
* * * * *