U.S. patent application number 15/086068 was filed with the patent office on 2017-10-05 for conveying system with vacuum wheel.
The applicant listed for this patent is CoreFlow Ltd.. Invention is credited to Ronen LAUTMAN, Isaac NAOR.
Application Number | 20170283189 15/086068 |
Document ID | / |
Family ID | 59929137 |
Filed Date | 2017-10-05 |
United States Patent
Application |
20170283189 |
Kind Code |
A1 |
NAOR; Isaac ; et
al. |
October 5, 2017 |
CONVEYING SYSTEM WITH VACUUM WHEEL
Abstract
A system for conveying a substrate includes a noncontact support
platform for supporting the substrate. A vacuum wheel is located
adjacent to the support platform. A rim of the vacuum wheel
includes perforations that open between an exterior of the rim and
an interior of the vacuum wheel. A fixed suction surface is
interior to the vacuum wheel and includes an opening of a conduit
that is connectable to a suction source. A chamber is formed by the
suction surface, walls of the vacuum wheel, and a section of the
peripheral rim that is adjacent to the suction surface and that
extends outward from the support platform. When suction is applied
to the conduit, the suction is applied via the chamber to the
perforations in the rim section so as to exert a pull on the
substrate toward the rim such that rotation of the vacuum wheel
conveys the substrate.
Inventors: |
NAOR; Isaac; (Hod-HaSharon,
IL) ; LAUTMAN; Ronen; (Haifa, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CoreFlow Ltd. |
Daliyat al-Karmel |
|
IL |
|
|
Family ID: |
59929137 |
Appl. No.: |
15/086068 |
Filed: |
March 31, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65G 47/848 20130101;
H01L 21/67721 20130101; H01L 21/67259 20130101; H01L 21/6838
20130101; H01L 21/67784 20130101; H01L 21/67706 20130101; B65G
51/03 20130101 |
International
Class: |
B65G 47/84 20060101
B65G047/84; H01L 21/67 20060101 H01L021/67; H01L 21/677 20060101
H01L021/677; B65G 51/03 20060101 B65G051/03 |
Claims
1. A system for conveying a substrate, the system comprising: a
noncontact support platform that is configured to support the
substrate at a nonzero distance from a surface of the noncontact
support platform; a vacuum wheel that is located adjacent to a part
of the noncontact support platform, a peripheral rim of the vacuum
wheel including a plurality of perforations that open between an
exterior of the rim and an interior of the vacuum wheel, said
plurality of perforations being arranged in a plurality of parallel
rows, the rows oriented at an oblique angle to an axle of the
vacuum wheel; a suction source that is further operable to apply
pressure; and a fixed suction surface that is interior to the
vacuum wheel, the suction surface including an opening of a
conduit, the conduit connected to the suction source, a chamber
being formed by the suction surface, walls of the vacuum wheel, and
a section of the peripheral rim that is adjacent to the suction
surface and that extends outward from the surface of the noncontact
support, wherein, when suction is applied by the suction source to
the conduit, the suction is applied via the chamber to the
perforations in said section of the peripheral rim so as to exert a
pull on the substrate toward the peripheral rim such that rotation
of the vacuum wheel conveys the substrate.
2. The system of claim 1, wherein the noncontact support platform
is configured to generate bidirectional stiffness.
3. The system of claim 1, wherein the noncontact support platform
comprises at least two parallel rails, and wherein the vacuum wheel
is located in a gap between two of said at least two parallel
rails.
4. The system of claim 1, wherein the vacuum wheel is located in an
opening of the noncontact support platform.
5. The system of claim 1, wherein the vacuum wheel is located
adjacent to an edge of the noncontact support platform.
6. (canceled)
7. A system for conveying a substrate, the system comprising: a
noncontact support platform that is configured to support the
substrate at a nonzero distance from a surface of the noncontact
support platform; a vacuum wheel that is located adjacent to a part
of the noncontact support platform, a peripheral rim of the vacuum
wheel including a plurality of perforations that open between an
exterior of the rim and an interior of the vacuum wheel, said
plurality of perforations being arranged such that, when the
applied suction is substantially constant, the exerted pull remains
substantially constant as the vacuum wheel is rotated; a suction
source that is further operable to apply pressure; and a fixed
suction surface that is interior to the vacuum wheel, the suction
surface including an opening of a conduit, the conduit connected to
the suction source, a chamber being formed by the suction surface,
walls of the vacuum wheel, and a section of the peripheral rim that
is adjacent to the suction surface and that extends outward from
the surface of the noncontact support, wherein, when suction is
applied by the suction source to the conduit, the suction is
applied via the chamber to the perforations in said section of the
peripheral rim so as to exert a pull on the substrate toward the
peripheral rim such that rotation of the vacuum wheel conveys the
substrate.
8. The system of claim 7, wherein a total length of intersection of
said plurality of perforations with any line that lies on the
peripheral rim and is substantially parallel to an axle of the
vacuum wheel is substantially constant.
9. The system of claim 7, wherein each pair of azimuthally adjacent
perforations of said plurality of perforations overlap by a
substantially constant azimuthal displacement.
10. The system of claim 1, wherein the rim includes a nonslip
material.
11. A system for conveying a substrate, the system comprising: a
noncontact support platform that is configured to support the
substrate at a nonzero distance from a surface of the noncontact
support platform; a vacuum wheel that is located adjacent to a part
of the noncontact support platform, a peripheral rim of the vacuum
wheel including a plurality of perforations that open between an
exterior of the rim and an interior of the vacuum wheel; and a
fixed suction surface that is interior to the vacuum wheel, the
suction surface including an opening of a conduit, the conduit
being configured for connection to a suction source, a chamber
being formed by the suction surface, walls of the vacuum wheel, and
a section of the peripheral rim that is adjacent to the suction
surface and that extends outward from the surface of the noncontact
support, the suction surface being convexly curved in a tangential
direction, a curvature of the suction surface being less than a
curvature of the rim, wherein, when suction is applied by the
suction source to the conduit, the suction is applied via the
chamber to the perforations in said section of the peripheral rim
so as to exert a pull on the substrate toward the peripheral rim
such that rotation of the vacuum wheel conveys the substrate.
12-13. (canceled)
14. The system of claim 1, further comprising a controller that is
configured to control the suction source to apply the suction or
the pressure.
15. The system of claim 14, wherein the controller is configured to
control the suction source to apply the pressure when a leading
edge of the substrate approaches said section of the wheel rim and
to apply the suction when a surface of the substrate is at said
section of the wheel rim.
16. The system of claim 15, further comprising one or a plurality
of sensors to detect when the substrate is at said section of the
wheel rim.
17. The system of claim 16, wherein said one or a plurality of
sensors comprises a proximity sensor.
18. The system of claim 14, wherein the controller is configured to
control the suction source to apply the pressure when a trailing
edge of the substrate is at said section of the wheel rim.
19. The system of claim 18, further comprising one or a plurality
of sensors to detect when the trailing edge is at said section of
the wheel rim.
20. The system of claim 19, wherein said one or a plurality of
sensors comprises a pressure sensor.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to conveying systems. More
particularly, the present invention relates to a conveying system
with a vacuum wheel.
BACKGROUND OF THE INVENTION
[0002] In the manufacture of large flat and thin objects, the
objects often need to be conveyed from one location to another. For
example, the objects may be transported from a workstation where a
manufacturing process is performed, to another workstation where a
different manufacturing process or inspection process is performed.
In some such processes, it is necessary to restrict contact with
the object to those regions of the object (e.g., typically margins
that are adjacent to the edges) that are not intended to perform a
critical function in the final product. Therefore, a contactless
support surface may be utilized to support the object
[0003] Examples of industries in which large thin and flat objects
are produced include the manufacture of thin glass or polymer
substrates for use in flat panel displays. Contact with such
substrates during manufacture or inspection may be limited to
regions, sometimes referred to as exclusion zones, that are located
at the edges of the substrate. When incorporated into the final
product (e.g., the display screen), the exclusion zones may serve a
primarily mechanical function (e.g., holding the thin plate in
place) rather than serving as a substrate for electronic components
or connections or serving another function that requires
contactless handling.
SUMMARY OF THE INVENTION
[0004] There is thus provided, in accordance with an embodiment of
the present invention, a system for conveying a substrate, the
system including: a noncontact support platform that is configured
to support the substrate at a nonzero distance from a surface of
the noncontact support platform; a vacuum wheel that is located
adjacent to a part of the noncontact support platform, a peripheral
rim of the vacuum wheel including a plurality of perforations that
open between an exterior of the rim and an interior of the vacuum
wheel; and a fixed suction surface that is interior to the vacuum
wheel, the suction surface including an opening of a conduit, the
conduit being connectable to a suction source, a chamber being
formed by the suction surface, walls of the vacuum wheel, and a
section of the peripheral rim that is adjacent to the suction
surface and that extends outward from the surface of the noncontact
support, wherein when suction is applied by the suction source to
the conduit, the suction is applied via the chamber to the
perforations in the section of the peripheral rim so as to exert a
pull on the substrate toward the peripheral rim such that rotation
of the vacuum wheel conveys the substrate.
[0005] Furthermore, in accordance with an embodiment of the present
invention, the noncontact support platform is configured to
generate bidirectional stiffness.
[0006] Furthermore, in accordance with an embodiment of the present
invention, the noncontact support platform includes at least two
parallel rails, and wherein the vacuum wheel is located in a gap
between two of the at least two parallel rails.
[0007] Furthermore, in accordance with an embodiment of the present
invention, the vacuum wheel is located in an opening of the
noncontact support platform.
[0008] Furthermore, in accordance with an embodiment of the present
invention, the vacuum wheel is located adjacent to an edge of the
noncontact support platform.
[0009] Furthermore, in accordance with an embodiment of the present
invention, the plurality of perforations are arranged in a
plurality of parallel rows, the rows oriented at an oblique angle
to an axle of the vacuum wheel.
[0010] Furthermore, in accordance with an embodiment of the present
invention, the plurality of perforations are arranged such that
when the applied suction is substantially constant, the exerted
pull remains substantially constant as the vacuum wheel is
rotated.
[0011] Furthermore, in accordance with an embodiment of the present
invention, a total length of intersection of the plurality of
perforations with any line that lies on the peripheral rim and is
substantially parallel to an axle of the vacuum wheel is
substantially constant.
[0012] Furthermore, in accordance with an embodiment of the present
invention, each pair of azimuthally adjacent perforations of the
plurality of perforations overlaps by a substantially constant
azimuthal displacement.
[0013] Furthermore, in accordance with an embodiment of the present
invention, the rim includes a nonslip material.
[0014] Furthermore, in accordance with an embodiment of the present
invention, the suction surface is convexly curved in a tangential
direction, a curvature of the suction surface being less than a
curvature of the rim.
[0015] Furthermore, in accordance with an embodiment of the present
invention, the system includes the suction source.
[0016] Furthermore, in accordance with an embodiment of the present
invention, the suction source is further operable to apply
pressure.
[0017] Furthermore, in accordance with an embodiment of the present
invention, the system includes a controller that is configured to
control the suction source to apply the suction or the
pressure.
[0018] Furthermore, in accordance with an embodiment of the present
invention, the controller is configured to control the suction
source to apply the pressure when a leading edge of the substrate
approaches the section of the wheel rim and to apply the suction
when a surface of the substrate is at the section of the wheel
rim.
[0019] Furthermore, in accordance with an embodiment of the present
invention, the system includes one or a plurality of sensors to
detect when the substrate is at the section of the wheel rim.
[0020] Furthermore, in accordance with an embodiment of the present
invention, the one or a plurality of sensors includes a proximity
sensor.
[0021] Furthermore, in accordance with an embodiment of the present
invention, the controller is configured to control the suction
source to apply the pressure when a trailing edge of the substrate
is at the section of the wheel rim.
[0022] Furthermore, in accordance with an embodiment of the present
invention, the system includes one or a plurality of sensors to
detect when the trailing edge is at the section of the wheel
rim.
[0023] Furthermore, in accordance with an embodiment of the present
invention, the one or a plurality of sensors includes a pressure
sensor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order for the present invention, to be better understood
and for its practical applications to be appreciated, the following
Figures are provided and referenced hereafter. It should be noted
that the Figures are given as examples only and in no way limit the
scope of the invention. Like components are denoted by like
reference numerals.
[0025] FIG. 1A shows a substrate conveying system, in accordance
with an embodiment of the present invention.
[0026] FIG. 1B shows another view of the substrate conveying system
shown in FIG. 1A while conveying a substrate.
[0027] FIG. 1C is a schematic diagram of the substrate conveying
system shown in FIG. 1A.
[0028] FIG. 2 schematically illustrates a vacuum wheel for a
substrate conveying system, in accordance with an embodiment of the
present invention.
[0029] FIG. 3A schematically illustrates structure of a vacuum
wheel for a substrate conveying system, in accordance with an
embodiment of the present invention.
[0030] FIG. 3B schematically illustrates internal structure of a
vacuum assembly of the vacuum wheel shown in FIG. 3A.
[0031] FIG. 4 is a flowchart depicting a method for controlling
operation of a substrate conveying system, in accordance with an
embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] In the following detailed description, numerous specific
details are set forth in order to provide a thorough understanding
of the invention. However, it will be understood by those of
ordinary skill in the art that the invention may be practiced
without these specific details. In other instances, well-known
methods, procedures, components, modules, units and/or circuits
have not been described in detail so as not to obscure the
invention.
[0033] Although embodiments of the invention are not limited in
this regard, discussions utilizing terms such as, for example,
"processing," "computing," "calculating," "determining,"
"establishing", "analyzing", "checking", or the like, may refer to
operation(s) and/or process(es) of a computer, a computing
platform, a computing system, or other electronic computing device,
that manipulates and/or transforms data represented as physical
(e.g., electronic) quantities within the computer's registers
and/or memories into other data similarly represented as physical
quantities within the computer's registers and/or memories or other
information non-transitory storage medium (e.g., a memory) that may
store instructions to perform operations and/or processes. Although
embodiments of the invention are not limited in this regard, the
terms "plurality" and "a plurality" as used herein may include, for
example, "multiple" or "two or more". The terms "plurality" or "a
plurality" may be used throughout the specification to describe two
or more components, devices, elements, units, parameters, or the
like. Unless explicitly stated, the method embodiments described
herein are not constrained to a particular order or sequence.
Additionally, some of the described method embodiments or elements
thereof can occur or be performed simultaneously, at the same point
in time, or concurrently. Unless otherwise indicated, the
conjunction "or" as used herein is to be understood as inclusive
(any or all of the stated options).
[0034] Some embodiments of the invention may include an article
such as a computer or processor readable medium, or a computer or
processor non-transitory storage medium, such as for example a
memory, a disk drive, or a USB flash memory, encoding, including or
storing instructions, e.g., computer-executable instructions, which
when executed by a processor or controller, carry out methods
disclosed herein.
[0035] In accordance with an embodiment of the present invention, a
conveying system is configured to convey a flat thin object, such
as a thin glass or polymer substrate. Any such thin flat object for
conveying by conveying system may be referred to herein, for
convenience, as a substrate, regardless of the intended use of the
object. The substrate conveying system is configured to
mechanically contact the surface of the substrate only at
predetermined regions herein referred to as exclusion zones.
Typically, the exclusion zones are located at edges of the
substrate. In some cases, an exclusion may be located elsewhere on
the substrate surface (e.g., in a longitudinal band that is
parallel to an intended direction of conveying of the
substrate).
[0036] The substrate conveying system includes one or more
noncontact support platforms. The noncontact support platform is
configured to support a substrate at a nonzero distance from an
exterior surface of the noncontact support platform. For example,
the noncontact support platform may be configured to support the
substrate on a cushion of air or another gas or fluid that is
formed between the exterior platform surface and the substrate.
[0037] For example, the noncontact support platforms may include an
array of pressure ports that are configured to expel pressurized
air, or another gas. A plurality of vacuum ports (connected to a
suction source) or exhaust ports (vented to the ambient atmosphere)
may be interspersed among the pressure ports. As a result, the
noncontact support platform may create bidirectional stiffness so
as to hold the substrate at a substantially fixed distance from the
noncontact support platform. A noncontact support platform that
generates bidirectional stiffness may be configured to support the
substrate from below (e.g., as would a standard air pressure table)
or from above.
[0038] For example, the noncontact support platform of the
substrate conveying system may include two or more parallel
noncontact support rails separated from one another by parallel
gaps. The longitudinal dimension of the noncontact rail surfaces
may be substantially parallel to a direction along which substrates
are to be conveyed. A substrate that the noncontact surface is
configured to support and convey may be sufficiently wide to cover
two or more of the noncontact rail surfaces. In this case, at least
some of the gaps that separate the parallel noncontact support
rails from one another may be situated so as to underlie an
exclusion zone of a substrate that is being supported and conveyed
by the noncontact support rails.
[0039] Alternatively or in addition, the noncontact support
platform may include a single surface with one or more openings.
The openings may be situated so as to underlie an exclusion zone of
a substrate that is being supported and conveyed by the noncontact
support platform.
[0040] The substrate conveying system includes one or more vacuum
wheels that are adjacent to the noncontact support platform. Each
vacuum wheel is configured to propel the substrate along a linear
direction. The linear direction is substantially tangential to the
rim of the vacuum wheel and substantially perpendicular to the axis
of the vacuum wheel. As used herein, a vacuum wheel is considered
to be adjacent to the noncontact support platform or to a part of
the noncontact support platform, if the vacuum wheel is located
within a gap between parallel noncontact support rails, within an
opening in a noncontact support platform, or adjacent to an
exterior lateral edge of the noncontact support platform. One side
of the vacuum wheel extends outward from the surface of the
noncontact support platform. (As used herein, outward from the
surface of the noncontact support platform refers to a direction
away from interior structure of the noncontact support platform and
toward a supported substrate.). The vacuum wheel may be mounted
such that when a substrate is supported by the noncontact support
platform, the vacuum wheel is approximately tangent to the
substrate.
[0041] Each vacuum wheel includes a wheel that is rotatable about
its axis and a fixed vacuum assembly. The rim of the wheel includes
an array of vacuum perforations that open from the interior of the
rim to the exterior surface of the rim. As used herein, the rim of
the wheel refers to the peripheral rim, that is, the surface of the
wheel that is at the external perimeter of the wheel (e.g., the
surface of the wheel that is configured to contact the substrate).
Perforations refer to holes or openings that perforate the rim
regardless of how the holes or openings are formed (e.g., whether
by perforating a previously contiguous surface or a surface that
was formed together with holes or openings). At least a part of the
interior of the wheel that is adjacent to the wheel rim is hollow.
A fixed vacuum assembly is configured to apply a vacuum (used
herein interchangeably with the term "suction") to the vacuum
perforations of a section of the perimeter rim that is currently at
a predetermined orientation, herein referred to as active
perforations. The section that includes the active perforations
includes at least a section of the wheel rim that extends maximally
(e.g., between 0.03 mm and 0.4 mm, or another nonzero distance)
outward beyond a plane of the surface of the noncontact support
platform. During rotation of the vacuum wheel, different sections
of the rim are rotated to the position to which the vacuum is
applied. The vacuum may be applied sequentially to the vacuum
perforations in different sections along the perimeter of the rim
to as the wheel is rotated about its axis. The active perforations
to which the vacuum is applied may exert a pull on a surface of a
substrate that covers those active perforations toward the rim of
the wheel to contact the rim. The contact between the rim and the
substrate may enable rotation of the wheel to convey the substrate
in a direction tangential to the direction of rotation of the
wheel.
[0042] For example, the vacuum wheel may be configured to contact a
surface of the substrate that faces the noncontact support
platform, e.g., through a gap or opening in the noncontact support
platform. In this case, where the noncontact support platform is
configured to support the substrate from below, the vacuum assembly
may be configured to apply the vacuum to upward facing vacuum
perforations in a section of the wheel rim that is currently at the
top of the wheel. Where the noncontact support platform is
configured to support the substrate from above, the vacuum assembly
may be configured to apply the vacuum to the downward facing vacuum
perforations in a section of the wheel rim that is currently at the
bottom of the wheel. Alternatively or in addition, a vacuum wheel
may be configured to contact a side of the substrate that is
opposite the side that faces the noncontact support platform. In
this case, where the noncontact support platform is configured to
support the substrate from below, the vacuum assembly may be
configured to apply the vacuum to downward facing vacuum
perforations in a section of the wheel rim that is currently at the
bottom of the wheel. Where the noncontact support platform is
configured to support the substrate from above, the vacuum assembly
may be configured to apply the vacuum to the upward facing vacuum
perforations in a section of the wheel rim that is currently at the
top of the wheel. Other configurations are possible.
[0043] The rim of the wheel surrounding or near the vacuum
perforations may be provided with a nonslip surface. For example, a
nonslip material on the rim may include a material that is
characterized by a high coefficient of friction for motion relative
to the substrate material. A nonslip material may include rubber or
a rubber-like plastic, or another nonslip material. The nonslip
surface may include texturing that is configured to increase
traction between the rim and the substrate. The nonslip surface of
the rim of the wheel may increase the traction between the vacuum
wheel and a surface of a substrate that is being conveyed (e.g.,
increased over traction between a rim without a nonslip surface and
the substrate surface). The increased traction may enable precise
and efficient conveying, without slippage, of the substrate to a
predetermined location.
[0044] The vacuum assembly includes a vacuum conduit opening in a
fixed suction surface through which the vacuum is applied. The
suction surface and conduit opening are located inside the wheel,
adjacent to the inward-facing surface of the rim of the wheel. The
suction surface and an adjacent section of the wheel rim form a
vacuum chamber via which the vacuum is applied to the vacuum
perforations (the active perforations) in the adjacent section.
Lateral edges of the suction surface are located sufficiently close
to the inward-facing surface of the rim (e.g., within 0.1
millimeter) so that sufficient vacuum (e.g., to enable the vacuum
perforations to exert a pull on the substrate) is maintained within
the vacuum chamber without impeding rotation of the wheel. For
example, the suction surface may be arced with a curvature that is
less than the curvature of the rim of the wheel. In this case, the
vacuum chamber that is formed between the suction surface and the
interior of the wheel may have a lune-like profile.
[0045] A suction source, such as a fan, blower, pump, compressor or
other source of suction or vacuum may be connected to a vacuum
inlet connector of the vacuum assembly. For example, the suction
source may connect a hose that connects to the suction source may
be connected to the vacuum inlet connector via a hose, pipe, tube,
or other conduit. The conduit may be branched such that a single
suction source may concurrently or otherwise apply a vacuum to the
vacuum assemblies of a plurality of vacuum wheels of the substrate
conveying system. In some cases, a branched conduit assembly may be
provided with one or more controllable valves to enable selective
application of vacuum to different vacuum wheels of the substrate
conveying system.
[0046] The vacuum perforations on the rim of the wheel of the
vacuum wheel may be arranged in a non-axially parallel pattern. As
used herein, a non-axially parallel pattern of the vacuum
perforations refers to a pattern in which sets of nearest
neighboring vacuum perforations are not arranged in rows that are
parallel to the wheel axis. Such a non-axially parallel pattern of
the vacuum perforations may avoid a situation where vacuum wheel
exerts a relatively large pull when an axially parallel row is in
contact with the substrate, and a relatively smaller pull when a
section of the rim between the rows is in contact with the
substrate surface.
[0047] In particular, the vacuum perforations may be arranged in a
staggered pattern. As used herein, a staggered pattern refers to an
arrangement of the vacuum perforations in which the vacuum
perforations are evenly distributed along an azimuth coordinate
about the perimeter of the rim. In the staggered pattern,
azimuthally adjacent (which could be widely separated in the axial
direction, e.g., near opposite sides of the wheel) vacuum
perforations overlap by a fixed amount. The azimuthal overlap
between azimuthally adjacent vacuum perforations may enable the
total area of vacuum perforations that is in contact with the
substrate surface to be approximately constant. An approximately
constant total area of vacuum perforations in contact with the
substrate surface may result in an approximately constant pull that
is exerted on the substrate. An approximately constant exerted pull
may enable accurate positioning of the substrate.
[0048] A controller of the substrate conveying system may be
configured to apply either pressure or suction to the vacuum
assembly. For example, a suction source may include a reversible
fan or blower. A direction of rotation or the fan or blower may be
reversed in order to blow air or gas into the vacuum chamber and
out the active perforations. As another example, separate suction
and pressure sources may be connected to a conduit that connects to
the vacuum assembly. A valve may be operated to selectively connect
either the suction source or the pressure source to the conduit,
and thus to the vacuum assembly.
[0049] A controller may be configured to control operation of one
or more components of the substrate conveying system. For example,
the controller may include a processing unit that is configured to
operate in accordance with programmed instructions. Alternatively
or in addition, the controller may include a circuit or circuitry
that is configured to control the components.
[0050] For example, the controller may control operation of one or
more of a motor for rotating the vacuum wheel, a transmission, a
suction or pressure source, one or more valves for selectively
connecting a suction or pressure source to one or more vacuum
wheels, a noncontact support platform (application of pressure or
vacuum), or another component of the substrate conveying
system.
[0051] The controller may be configured to control application of
one or more components of the substrate conveying system in
accordance with one or more values of quantities that are sensed by
one or more sensors. For example, the sensors may include one or
more of a proximity sensor, a position sensor, a pressure sensor, a
velocity sensor, or another type of sensor.
[0052] The controller may be configured to apply suction or
pressure to the vacuum assembly of a vacuum wheel in accordance
with whether the sensors indicate that the substrate is positioned
at the vacuum wheel. For example, pressure may be applied as the
substrate approaches the vacuum wheel. The pressure may provide a
cushion of pressurized air to prevent the leading end of the
substrate from violently impacting the rim of the vacuum wheel.
Once the substrate is positioned at (e.g., above or below) the
vacuum wheel, suction may be applied to the vacuum wheel to provide
the required traction between the vacuum wheel and the substrate.
When the trailing edge of the substrate leaves the vacuum wheel,
pressure may again be applied to the vacuum wheel (e.g., to soften
the separation of the trailing edge from the vacuum wheel, or in
anticipation of arrival of the leading edge of another
substrate).
[0053] For example, a proximity sensor that is located ahead (as
determined by the direction of motion of the substrate) of the
vacuum wheel may sense the approach of the leading edge of the
substrate. At this point, pressure may be applied to the vacuum
wheel. An additional proximity sensor that is located after the
vacuum wheel may indicate that the leading edge has passed the
vacuum wheel and that (e.g., when both proximity sensors sense the
proximity of the substrate) the substrate and is now covering the
vacuum wheel. At this point, suction may be applied to the vacuum
wheel. A pressure sensor (e.g., a vacuum sensor) may indicate that
the substrate is being held to the vacuum wheel by the suction. The
pressure sensor may be placed anywhere between the suction source
and the vacuum chamber. The pressure sensor may further indicate
when the trailing edge of the substrate has reached the vacuum
wheel (e.g., sensed as an increase in pressure as vacuum
perforations on the rim of the wheel are fully or partially
uncovered). At this point, pressure may be applied again to the
vacuum wheel.
[0054] FIG. 1A shows a substrate conveying system, in accordance
with an embodiment of the present invention. FIG. 1B shows another
view of the substrate conveying system shown in FIG. 1A while
conveying a substrate. FIG. 1C is a schematic diagram of the
substrate conveying system shown in FIG. 1A.
[0055] Substrate conveying system 10 includes a system frame 11 to
which various components of substrate conveying system 10 are
mounted. System frame 11 may include a moveable table or a fixed
fixture or structure. One or more of noncontact support platform
12, motor housing 23, wheel axle support 25, or other components of
substrate conveying system 10 may be mounted to system frame
11.
[0056] Noncontact support platform 12, in the example shown in
FIGS. 1A and 1B, includes a plurality of parallel support rails 27
separated by gap 13. Each support rail 27 of noncontact support
platform 12 includes a plurality of ports 14. Other configurations
of noncontact support platform 12, e.g., in the form of a single
extended rectangular platform or other shape, may be used. Pressure
or vacuum may be applied to each port 14 via a manifold of conduits
that are incorporated within noncontact support platform 12.
[0057] Noncontact support platform 12 is configured to support a
substrate 30 without mechanical contact between a solid component
of noncontact support platform 12 and substrate 30. For example,
substrate 30 may include a sheet of glass (e.g., for a flat panel
display), or another flat, thin object. A size of noncontact
support platform 12 may be configured (e.g., by its dimensions or
by the number and size of parallel support rails 27 that are
incorporated into noncontact support platform 12, or otherwise) to
support a particular size and shape of substrate 30 (e.g., for a
particular production line). In the case that noncontact support
platform 12 is configured to provide bidirectional stiffness (via a
fluidic spring effect), noncontact support platform 12 may be
configured to support substrate 30 at a substantially fixed
distance (e.g., between 0.03 mm and 0.4 mm) from the surface of
noncontact support platform 12.
[0058] Vacuum wheel 16 is located in gap 13 between parallel
support rails 27. The direction of rotation of vacuum wheel 16,
perpendicular to wheel axle 19, is substantially parallel to the
longitudinal dimension of parallel support rails 27 of noncontact
support platform 12. Alternatively, vacuum wheel 16 may be located
in an opening within (e.g., entirely or partly surrounded by) a
single contiguous section of a noncontact support platform.
Alternatively, vacuum wheel 16 may be located adjacent to an
exterior edge of noncontact support platform 12 (e.g., when the
exclusion zone is located at an edge of substrate 30 that extends
beyond noncontact support platform 12).
[0059] Vacuum wheel 16 may be positioned relative to noncontact
support platform 12 such that when a substrate 30 is supported by
noncontact support platform 12, vacuum wheel 16 is positioned at an
exclusion zone 32 of substrate 30. For example, exclusion zone 32
may include a region of substrate 30 that is not configured to
incorporate or support electronic components or contacts in a
product that incorporates substrate 30. Therefore, physical contact
between vacuum wheel 16 and exclusion zone 32 may be permitted. The
width of vacuum wheel 16 is limited to a width that is no wider
than the width of exclusion zone 32.
[0060] Since types of substrate 30 may have differently sized and
located exclusion zones 32, a vacuum wheel may be designed for a
particular type of substrate 30. Noncontact support platform 12 may
be custom designed for a particular substrate 30, or may be
designed in manner (e.g., with modular components that may be
assembled into a particular configuration for appropriately sized
and positioned vacuum wheels 16, adjustable distances gaps between
separate parallel support rails 27, or otherwise) to accommodate a
particular substrate 30.
[0061] Wheel rim 16a of vacuum wheel 16 may be covered by nonslip
cover 16. For example, nonslip cover 17 may include a coating or
band of rubber or a similar high-friction natural or synthetic
material. Alternatively or in addition, wheel rim 16a may be
constructed of a nonslip material.
[0062] A vacuum chamber 41 (visible in FIGS. 3A and 3B) may be
formed within vacuum wheel 16 by structure of vacuum assembly 40,
and by a currently adjacent section of each of wheel rim 16a, full
wall 16b, and partial wall 16c of vacuum wheel 16. The space that
is surrounded by partial wall 16c may be filled by stationary plate
43 of vacuum assembly 40. Wheel rim 16a is perforated by an array
of a plurality of vacuum perforations 18. At any time during
rotation of vacuum wheel 16, some of vacuum perforations 18 (active
perforations) connect vacuum chamber 41 to the ambient atmosphere
outside of vacuum wheel 16.
[0063] Vacuum perforations 18 are arranged in a staggered pattern.
The staggered pattern includes parallel rows 20 of vacuum
perforations 18. Each of parallel rows 20 includes an identical
number of vacuum perforations 18. Each row 20 of vacuum
perforations 18 is oriented at an oblique angle to wheel axle 19 of
vacuum wheel 16.
[0064] Suction or pressure may be applied to vacuum perforations 18
by operation of suction/pressure source device 50. Suction/pressure
source device 50 may be connected to vacuum assembly 40 via conduit
24 and vacuum assembly connector 22.
[0065] For example, suction/pressure source device 50 may include a
fan, turbine, or another component of a blower that is reversible.
When operated in one direction, the blower of suction/pressure
source device 50 may apply suction to vacuum chamber 41 and the
adjacent vacuum perforations 18 while venting the sucked air to the
ambient atmosphere. When operated in the reverse direction, the
blower of suction/pressure source device 50 may suck air from the
ambient atmosphere and force the pressurized air into vacuum
chamber 41.
[0066] Alternatively or in addition, suction/pressure source device
50 may include separate suction or pressure sources. The separate
vacuum and pressure sources may operate continuously.
Suction/pressure source device 50 (or conduit 24) may include a
valve that selectively connects either the suction source or the
pressure source to conduit 24 or to vacuum assembly 40.
[0067] In some cases, suction/pressure source device 50 may include
a suction source only.
[0068] Operation of suction/pressure source device 50 may be
controlled by system controller 52. For example, controller 52 may
control a direction of rotation of a fan or turbine of a blower of
suction/pressure source device 50. Controller 52 may control a
speed of rotation of a fan or turbine of a blower of
suction/pressure source device 50.
[0069] For example, controller 52 may include one or more
programmable data processing units or computers that may operate in
accordance with programmed instructions. Alternatively or in
addition, controller 52 may include analog or digital circuitry
that is configured to operate one or more devices or units of
substrate conveying system 10 in response to operation of one or
more user-operable controls 56, or in response to one or more
sensed conditions.
[0070] User-operable controls 56 may include one or more switches,
levers, touch screens, pushbuttons, keys, knobs, or other controls
that may be operated by a user. For example, a user may operate
user-operable controls 56 to indicate starting or stopping
operation of substrate conveying system 10, a direction (e.g.,
forward or reverse) of conveying, a speed of conveying, a type of
substrate 30 that is to be conveyed, a characteristic of a
substrate 30 that is to be conveyed (e.g., size, weight, density,
thickness, or other characteristic), a mode of operation, or
another user input indication.
[0071] Controller 52 may receive signals from one or more sensors
54. For example, one or more of sensors 54 may be configured to
sense a quantity that is indicative of a location of a substrate 30
relative to vacuum wheel 16. Such sensors may include, for example,
a proximity sensor (e.g., optical, electromagnetic, acoustic, or
mechanical proximity sensor), a pressure sensor (e.g., that is
configured to sense an air pressure in vacuum chamber 41, vacuum
assembly 40, conduit 24, or elsewhere), a motion sensor, a location
sensor (e.g., optical), or another type of sensor that is
configured to sense a quantity that is indicative of a position of
a substrate 30.
[0072] Controller 52 may be configured to control operation of
suction/pressure source device 50 in accordance with a quantity
that is sensed by sensors 54. For example, controller 52 may
control suction/pressure source device 50 to provide pressure to
vacuum perforations 18 of vacuum wheel 16 when a signal from one or
more sensors 54 is indicative of that a leading edge of substrate
30 is approaching vacuum wheel 16. Controller 52 may control
suction/pressure source device 50 to provide suction to vacuum
perforations 18 of vacuum wheel 16 when a signal from one or more
sensors 54 is indicative of the leading edge of substrate 30 having
crossed vacuum wheel 16 (such that the surface of substrate 30 is
opposite vacuum wheel 16). Similarly, controller 52 may control
suction/pressure source device 50 to provide pressure to vacuum
perforations 18 of vacuum wheel 16 when a signal from one or more
sensors 54 is indicative of that a trailing edge of substrate 30 is
about to leave vacuum wheel 16. Such control may soften or
eliminate mechanical shock to substrate 30 when establishing or
breaking contact with vacuum wheel 16.
[0073] Motor housing 23 is configured to house motor 26. Motor 26
is configured to apply a torque to wheel axle 19 of vacuum wheel
16. Motor 26 may include a one or more motors.
[0074] Motor housing 23 may house transmission 27. Torque may be
transmitted from motor 26 to wheel axle 19 via transmission 27. For
example, transmission 27 may include a direct connection of a shaft
of motor 26 to wheel axle 19, or may include one or more gears.
Transmission 27 may be adjustable, e.g., with an adjustable gear
ratio.
[0075] Operation of motor 26 or transmission 27, or both, may be
controlled by controller 52. For example, controller 52 may be
configured to operate motor 26, or to engage transmission 27, when
sensors 54 indicate that a substrate 30 is near or in contact with
vacuum wheel 16. Alternatively or in addition, controller 52 may be
configured to operate motor 26 continuously when power is supplied
to substrate conveying system 10.
[0076] FIG. 2 schematically illustrates a vacuum wheel for a
substrate conveying system, in accordance with an embodiment of the
present invention.
[0077] Vacuum assembly 40 is configured to be held in a fixed
position and orientation relative to system frame 11. Vacuum wheel
16, including wheel rim 16a, full wall 16b, and partial wall 16c
are rotatable together with wheel axle 19. Bearing 44 enables wheel
axle 19 to rotate freely relative to vacuum assembly 40.
[0078] Vacuum perforations 18 are arranged on wheel rim 16a such
that when a suction force that is applied by suction/pressure
source device 50 is constant, vacuum perforations 18 exert a
substantially constant pull on substrate 30.
[0079] For example, vacuum perforations 18 may be arranged on wheel
rim 16a in a staggered arrangement in parallel rows 20 that are
each oriented at an oblique angle to wheel axle 19. An orientation
of and spacing between parallel rows 20 may be selected, taking
into consideration the size of vacuum perforations 18, to enable an
approximately uniform and constant suction force on a substrate 30.
For example, the total length of intersection of an axial rim line
21 (a line on the surface of wheel rim 16a that is oriented
parallel to wheel axle 19) with vacuum perforations 18 may be
considered. When the staggered arrangement of vacuum perforations
18 is such as to create a substantially uniform and constant
suction force, the total length of intersection with vacuum
perforations 18 of any axial rim line 21 may be substantially equal
to the total length of intersection with any other axial rim line
21.
[0080] Vacuum perforations 18 may be arranged such that each pair
of azimuthally adjacent vacuum perforations 18 are displaced from
one another (or, equivalently, overlap) in the azimuthal direction
by a substantially equal distance. As used herein, two vacuum
perforations 18 are referred to as azimuthally adjacent when
progressing along the wheel rim 16a, one vacuum perforation 18 of
the pair is encountered immediately after encountering the other
vacuum perforation 18 without first encountering another vacuum
perforation 18 (e.g., whether the vacuum perforations 18 of the
pair are adjacent to one another within a single row 20, or include
a vacuum perforation 18 at one end 20a of one row 20 and a vacuum
perforation 18 at an opposite end 20b of another row 20).
Equivalently, when all vacuum perforations 18 are projected onto a
single plane that is perpendicular to wheel axle 19, two vacuum
perforations 18 are azimuthally adjacent when they are adjacent
within the projection.
[0081] FIG. 3A schematically illustrates structure of a vacuum
wheel for a substrate conveying system, in accordance with an
embodiment of the present invention. FIG. 3B schematically
illustrates internal structure of a vacuum assembly of the vacuum
wheel shown in FIG. 3A.
[0082] Motor shaft 45 is rotatable by motor 26. Motor shaft 45 is
coupled to wheel axle 19 such that rotation of motor shaft 45 may
rotate wheel axle 19 and vacuum wheel 16. For example, the coupling
between motor shaft 45 and wheel axle 19 may include flexible
coupling 47. Flexible coupling 47 may tolerate or enable limited
movement or misalignment between motor shaft 45 and wheel axle 19,
while continuing to transmit torque. The tolerance to limited
movement or misalignment may reduce stress that could otherwise
result.
[0083] Wheel axle 19 connects to full wall 16b of vacuum wheel 16
at hub structure 42. The interior of vacuum wheel 16 between full
wall 16b, wheel rim 16a, and hub structure 42 is hollow. Active
components of vacuum assembly 40 are configured to fit in the
hollow space.
[0084] Vacuum assembly connector 22 connects suction/pressure
source device 50 (via conduit 24) via internal conduit 46 to vacuum
assembly conduit opening 48. Vacuum assembly conduit opening 48
opens under active perforations 18a in suction surface 51. Suction
surface 51 extends laterally in the tangential direction of wheel
rim 16a with a convex curvature that is less than the curvature of
wheel rim 16a to close to the interior surface of wheel rim 16a.
Alternatively, the suction surface may be substantially flat or
have a concave curvature.
[0085] Suction surface 51 and wheel rim 16a form vacuum chamber 41.
Since suction surface 51 has convex curvature, the profile of
vacuum chamber 41 is lune shaped. (The shape of vacuum chamber 41
would be different for a flat or concave suction surface.)
Tangential edges 51a of suction surface 51 approach the inner
surface of wheel rim 16a sufficiently closely such that inflow or
outflow of air in the gap between tangential edges 51a and wheel
rim 16a is impeded Similarly axial edges 51b of suction surface 51
approach the inner surface of full wall 16b and partial wall 16c
sufficiently closely such that inflow or outflow of air in the gap
between axial edge 5 lb and either full wall 16b or partial wall
16c is impeded. In some cases, tangential edge 51a or axial edge
51b may be provided with a partially sealing structure (e.g., a
felt pad, soft brush bristles, or similar structure) that further
impedes air flow through the gap without significantly impeding or
interfering with rotation of vacuum wheel 16.
[0086] Thus, when suction is applied to vacuum assembly conduit
opening 48, a partial vacuum may form within vacuum chamber 41. The
suction may thus be applied to active perforations 18a that open
between vacuum chamber 41 and the ambient atmosphere. Thus, the
suction may hold an adjacent substrate 30 to the surface of wheel
rim 16a. Similarly, when pressurized air is forced into vacuum
assembly conduit opening 48, air in vacuum chamber 41 may become
pressurized. The pressure may thus be applied to active
perforations 18a that open between vacuum chamber 41 and the
ambient atmosphere. Thus, the pressure may push a surface of an
adjacent substrate (e.g., a surface at a leading or trailing edge
of substrate 30) away from the surface of wheel rim 16a.
[0087] In accordance with an embodiment of the present invention,
controller 52 of substrate conveying system 10 may be configured to
control components of substrate conveying system 10 in accordance
with a conveying system control method.
[0088] FIG. 4 is a flowchart depicting a method for controlling
operation of a substrate conveying system, in accordance with an
embodiment of the present invention.
[0089] It should be understood with respect to any flowchart
referenced herein that the division of the illustrated method into
discrete operations represented by blocks of the flowchart has been
selected for convenience and clarity only. Alternative division of
the illustrated method into discrete operations is possible with
equivalent results. Such alternative division of the illustrated
method into discrete operations should be understood as
representing other embodiments of the illustrated method.
[0090] Similarly, it should be understood that, unless indicated
otherwise, the illustrated order of execution of the operations
represented by blocks of any flowchart referenced herein has been
selected for convenience and clarity only. Operations of the
illustrated method may be executed in an alternative order, or
concurrently, with equivalent results. Such reordering of
operations of the illustrated method should be understood as
representing other embodiments of the illustrated method.
[0091] Conveying system control method 100 may be executed by a
controller 52 of a substrate conveying system 10. Conveying system
control method 100 may be executed continuously during operation of
substrate conveying system 10, or may be executed in response to an
action by an operator of substrate conveying system 10, or in
response to a sensed event.
[0092] As a leading edge of a substrate 30 approaches vacuum wheel
16, controller 52 may operate suction/pressure source device 50 to
apply pressure to active perforations 18a of vacuum wheel 16 (block
120). For example, a default mode of operation of substrate
conveying system 10 may include operating suction/pressure source
device 50 to provide pressure. Alternatively or in addition,
controller 52 may be configured to operate suction/pressure source
device 50 to provide pressure when a sensor 52, such as a position
sensor or a proximity sensor, indicates the approach of the leading
edge of substrate 30. In this case, until the approach is
indicated, suction/pressure source device 50 may be configured to
apply neither pressure nor suction to active perforations 18a, or
may be configured to apply a lower pressure or suction to active
perforations 18a.
[0093] Application of pressure to vacuum wheel 16 may continue
until sensors 52 indicate that the surface of substrate 30 is at
(e.g., covers or is opposite) vacuum wheel 16 (block 130). For
example, a proximity or position sensor may indicate that the
leading edge has passed at least part of vacuum wheel 16. An
optical or acoustic position sensor may sense that substrate 30 is
at (e.g., blocks a straight line path at or near) vacuum wheel 16.
A pressure sensor may indicate that substrate 30 is affecting air
flow out of active perforations 18a.
[0094] When it is sensed that substrate 30 is at vacuum wheel 16,
controller 52 may control suction/pressure source device 50 to a
apply suction to active perforations 18a of vacuum wheel 16 (block
140).
[0095] Application of the suction may continue until it is sensed
that a trailing edge of substrate 30 has reached vacuum wheel 16
(block 150). For example, a pressure sensor may indicate that
suction is being reduced by partial uncovering of active
perforations 18a by the trailing edge of substrate 30. A proximity
or position sensor may indicate that the trailing edge is at vacuum
wheel 16.
[0096] When the trailing edge of substrate 30 is sensed to be at
vacuum wheel 16, controller 52 may operate suction/pressure source
device 50 to provide pressure to active perforations 18a of vacuum
wheel 16 (block 160).
[0097] Application of the pressure may continue until the trailing
edge is sensed to have completely left vacuum. In some cases,
application of pressure may be a default condition that continues
until the substrate is sensed to be at the vacuum wheel (e.g., as
in the operation of block 130). In some cases, neither pressure nor
suction is applied to vacuum wheel 16 until the approach of a
substrate 30 is sensed. In some cases, suction may be applied as a
default condition.
[0098] Different embodiments are disclosed herein. Features of
certain embodiments may be combined with features of other
embodiments; thus certain embodiments may be combinations of
features of multiple embodiments. The foregoing description of the
embodiments of the invention has been presented for the purposes of
illustration and description. It is not intended to be exhaustive
or to limit the invention to the precise form disclosed. It should
be appreciated by persons skilled in the art that many
modifications, variations, substitutions, changes, and equivalents
are possible in light of the above teaching. It is, therefore, to
be understood that the appended claims are intended to cover all
such modifications and changes as fall within the true spirit of
the invention.
[0099] While certain features of the invention have been
illustrated and described herein, many modifications,
substitutions, changes, and equivalents will now occur to those of
ordinary skill in the art. It is, therefore, to be understood that
the appended claims are intended to cover all such modifications
and changes as fall within the true spirit of the invention.
* * * * *