FIELD OF THE INVENTION
[001] The subject matter in general relates to the field of photo voltaic
solar cells. More particularly, but not exclusively, the subject matter relates
to applying conductor paste on thin film samples used in developing high
efficiency solar cells.
BACKGROUND OF THE INVENTION
[002] Background description includes information that may be useful
in understanding the present subject matter. It is not an admission that any
of the information provided herein is prior art or relevant to the presently
claimed subject matter, or that any publication specifically or implicitly
referenced is prior art.
[003] Photovoltaic (PV) power is gradually emerging as a viable source
of renewable energy. Silicon solar cells comprising of mono crystalline (c-
Si) and multi-crystalline (mC-Si) varieties constitute 90% of the
manufactured solar cells. Thin film solar cell technologies are also promising
as they have very low temperature coefficient and their performance is not
impeded by low intensity light.
[004] The optimization of the p-type, n-type and the intrinsic
amorphous Silicon (a-Si) thin film layers play a very important role in the
research of HIT solar cells. The optical band gap, conductivity and
deposition rate of the amorphous layers are all tailored by the PECVD
process parameters. P-type and n-type layers are deposited nonnaJ glass
slides and intrinsic layer is deposited on alkali free borosilicate glass so that
the optical and electrical characteristics can be conveniently measured.

[005] During experiments to save on the cost of silicon substrate, glass
slides are used for deposition of individual layers. To measure the electrical
conductivity of thin layers of a-Si, they are deposited on glass slides, and
the conducting silver contacts are applied on them. These contacts are then
dried in a furnace. Usually these pads are made manually with the help of
external applicator, screens or stencil, which results in pads with a
considerable degree of variation in shape and dimensions. This leads to
inaccurate measurement of conductivity and conclusions.
[006] United States Patent US4104091A relates to application of
semiconductor diffusants to solar cells by screen printing. Diffusants are
applied onto semiconductor solar cell substrates using screen printing
techniques. The method is applicable to square and rectangular cells and
can be used to apply dopants of opposite types to the front and back of the
substrate. Then, simultaneous diffusion of both dopants can be performed
with a single furnace pass. This patent relates to application of diffusants
on semi-conductor through screen printing and does not provide a solution
for formation of small conducting pad patterns for thin film samples.
[007] United States Patent US6539856B2 relates to a method of screen
printing stencil production. A coated film product comprises a support base,
a stencil-forming layer and an intermediate release layer. The stencil
forming layer is a blend of two grades of polyvinyl alcohol having different
degrees of hydrolysis. The stencil-forming layer is imaged by drop-wise
application of cross-linking agent which hardens the stencil-forming layer to
resist washing out with water. The hardened areas remaining after washing
out are however sufficiently tacky for the washed-out film to adhere to the
screen mesh by application of pressure and, after removal of the support

base, from the stencil layer of screen-printing screen. Thus, the instant
invention relates to the method of stencil production using screens and is
not related to printing of conducting pad patterns for thin film sample
characterization.
[008] United States Patent US6482740B2 relates to a method of
growing electrical conductors by reducing metal oxide film with organic
compound containing -OH, -CHO, or -COOH. This invention relates to
manufacturing of integrated circuits (ICs) and especially conductive layers
suitable for use in an IC. According to the preferred method, a metal oxide
thin film is deposited on a substrate surface and reduced thereafter
essentially into a metallic fonn with an organic reducing agent. The metal
oxide is preferably deposited according to the principles of atomic layer
deposition (ALD) using a metal source chemical and an oxygen source
chemical. The reduction step is preferably carried out in an ALD reactor
using one or more vaporized organic compounds that contain at least one
functional group selected from the group consisting of -OH, -CHO and -
COOH. Therefore, the instant invention relates to growing of metal contact
and in no way relates to screen printing.
[009] Film conductor patterns on a ceramic substrate which comprises
the steps of forming grooves in a positive-working photoresist layer on the
substrate by the photolithographic technology, filling the grooves with a
conductive paste by squeezing with a squeegee, removing the photoresist
layer by a wet process, and firing the remaining conductive paste pattern
is improved. By the improvements, the conductive paste is squeezed into
the grooves by the screen printing technique using a mask, and/or the
solvent in the conductive paste consists essentially of one or more
hydrocarbons, and/or the squeegee is made of a material having a flexural

modulus in a range of 30-200 kgf/mm2. This invention relates to the
complex method of forming thick-film conductor patterns using
photolithographic technology and in no way relates to the simple
mechanical and portable device for making conductor patterns on thin
film samples.
[0010] US patent no US5178685A relates to a method of forming solar
cell contacts and interconnecting solar cells. Photovoltaic cells with silver-
rich thick film electrical contacts having superior thermal aging properties
are disclosed. The silver-rich contacts are formed by firing a silver ink or
paste wherein substantially all of the silver in the ink or paste before firing
is in the form of spherical particles. Preferably inter-cell connections to the
contacts are accomplished using a tin and silver solder paste comprising
between about 96% tin/4% silver and 98% tin/2% silver. Solar cells having
contacts incorporating the present invention exhibit the capability of
withstanding temperatures in the range of 150°C, with little or no thermal
degradation of contact peel strength in the region of the solder bonds.
Therefore, the instant invention relates to the method of forming solar cell
contacts by using particles and conducting pastes by depositing the same
on surface and does not relate to application of conducting paste for
measurement of electrical parameters of thin film samples.
OBJECTS OF THE INVENTION
[0011] In view of the foregoing limitations inherent in the state of the
art, some of the objects of the present disclosure, which at least one
embodiment herein satisfy, are listed herein below.
[0012] It is an object of the present disclosure to propose a device for
applying conductor paste on thin film samples.

[0013] It is another object of the present disclosure to propose a device
to apply a coating of the conductor paste in one touch with the help of
guided support.
[0014] It is yet another object of the present disclosure to propose a
device to control the flow of conductor paste so that excess paste does not
reach the substrate.
[0015] It is still yet another object of the present disclosure to propose
a device to avoid smearing of conductor pads.
[0016] It is still yet another object of the present disclosure to propose
a device for developing high efficiency silicon solar cells.
[0017] These and other objects and advantages of the present invention
will be apparent to those skilled in the art after a consideration of the
following detailed description taken in conjunction with the accompanying
drawings in which a preferred form of the present invention is illustrated.
SUMMARY OF THE INVENTION
[0018] This summary is provided to introduce concepts related to an
apparatus and a method for drawing a bank tube trapped in a drum of a
steam generator. The concepts are further described below in the detailed
description. This summary is not intended to identify key features or
essential features of the claimed subject matter, nor is it intended to be
used to limit the scope of the claimed subject matter.
[0019] The present disclosure relates to a portable device for applying
conductor paste on thin film samples. The portable device comprises a
printing screen configured to receive conductor paste, a squeegee arranged

above the printing screen and a flood bar arranged above the printing
screen and adjacent to the squeegee. The squeegee is configured to spread
the conductor paste on the printing screen in a first direction and force the
conductor paste through the printing screen when the squeegee is moved
in contact with the printing screen in the first direction. The flood bar is
configured to accumulate unused conductor paste when the flood bar is
moved in contact with the printing screen in a second direction, wherein the
second direction is opposite to that of the first direction.
[0020] The present disclosure further relates to a method for applying
conductor paste on thin film samples. The method comprises receiving
conductor paste using a printing screen. Spreading, using a squeegee, the
conductor paste on the printing screen in a first direction, wherein the
squeegee is arranged above the printing screen. Forcing the conductor
paste through the printing screen, when the squeegee is moved in contact
with the printing screen in the first direction. Accumulating, using a flood
bar, unused conductor paste when the flood bar is moved in contact with
the printing screen in a second direction. The flood bar is arranged above
the printing screen and adjacent to the squeegee, and the second direction
is opposite to that of the first direction.
[0021] Other objects, features and advantages of the present disclosure
will become apparent from the following detailed description. It should be
understood, however, that the detailed description and the specific
examples, while indicating specific embodiments of the invention, are given
by way of illustration only, since various changes and modifications within
the spirit and scope of the invention will become apparent to those skilled
in the art from this detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0022] While the specification concludes with claims particularly pointing
out and distinctly claiming the subject matter that is regarded as forming
the present subject matter, it is believed that the present disclosure will be
better understood from the following description taken in conjunction with
the accompanying drawings, where like reference numerals designate like
structural and other elements, in which:
[0023] FIG. 1 discloses a portable device 100 for applying conductor
paste on thin film samples, in accordance with an embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The detailed description of various exemplary embodiments of
the disclosure is described herein with reference to the accompanying
drawings. It should be noted that the embodiments are described herein in
such details as to clearly communicate the disclosure. However, the amount
of details provided herein is not intended to limit the anticipated variations
of embodiments; on the contrary, the intention is to cover all modifications,
equivalents, and alternatives falling within the spirit and scope of the
present disclosure as defined by the appended claims.
[0025] It is also to be understood that various arrangements may be
devised that, although not explicitly described or shown herein, embody the
principles of the present disclosure. Moreover, all statements herein reciting
principles, aspects, and embodiments of the present disclosure, as well as
specific examples, are intended to encompass equivalents thereof.
[0026] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of example

embodiments. As used herein, the singular forms “a”, “an”, and “the” are
intended to include the plural forms as well, unless the context clearly
indicates otherwise. It will be further understood that the terms
“comprises”, “comprising”, “includes”, “consisting” and/or “including” when
used herein, specify the presence of stated features, integers, steps,
operations, elements and/or components, but do not preclude the presence
or addition of one or more other features, integers, steps, operations,
elements, components and/or groups thereof.
[0027] It should also be noted that in some alternative implementations,
the functions/acts noted may occur out of the order noted in the figures.
For example, two figures shown in succession may, in fact, be executed
concurrently or may sometimes be executed in the reverse order, depending
upon the functionality/acts involved.
[0028] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which example
embodiments belong. It will be further understood that terms, e.g., those
defined in commonly used dictionaries, should be interpreted as having a
meaning that is consistent with their meaning in the context of the relevant
art and will not be interpreted in an idealized or overly formal sense unless
expressly so defined herein.
[0029] Referring to FIG. 1, a portable device 100 for applying conductor
paste on thin film samples is disclosed in accordance with an embodiment.
The portable device 100 comprises a printing screen 102, a squeegee 104,
a flood bar 108, a rail assembly 112, a movable arm 114 and an
intermediate arm 118.

[0030] The rail assembly 112 supports the squeegee 104 and the flood
bar 108 such that the squeegee 104 and the flood bar 108 moves as the
rail assembly 112 is moved.
[0031] In an embodiment, the squeegee 104 and the flood bar 108 are
detachably attached to the rail assembly 112.
[0032] In an embodiment, the flood bar 108 is placed adjacent to the
squeegee 104.
[0033] In an embodiment, the rail assembly 112 is configured to move
the squeegee 104 and the flood bar 108 up and down in direction 116.
[0034] The printing screen 102 is arranged below the squeegee 104
and the flood bar 108 such that the squeegee 104 and the flood bar 108
are configured to be in contact with the printing screen 102 when the
squeegee 104 and the flood bar 108 are moved by the rail assembly 112
in the direction 116.
[0035] In an embodiment, the printing screen 102 is configured to
receive conductor paste that is to be applied on thin film samples. The thin
film sample that is to be applied with the conductor paste is placed below
the printing screen 102.
[0036] In an embodiment, the printing screen 102 is made of polyester
and is porous enough to allow the conductor paste to pass through it.
[0037] In an embodiment, to apply the conductor paste to the thin film
sample, the rail assembly 112 moves the squeegee 104 down in the
direction 116, so that the squeegee 104 is in contact with the printing
screen 102. The squeegee 104 is moved in contact with the printing screen

102 in a first direction 106, to spread the conductor paste along the
printing screen 102 and to force it through the printing screen 102. The
conductor paste, which is forced through the printing screen 102, is applied
on the thin film sample that is placed below the printing screen 102.
[0038] In an embodiment, the rail assembly 112 moves the flood bar
108 up in the direction 116 so that the flood bar 108 is not in contact with
the printing screen 102 when the squeegee 104 is in contact with the
printing screen 102.
[0039] In an embodiment, when the flood bar 108 is moved in contact
with the printing screen 102 in a second direction 110, the unused
conductor paste is accumulate for the squeegee 104 to spread it in the next
cycle.
[0040] In an embodiment, the squeegee 104 is not in contact with the
printing screen 102 when the flood bar 108 is in contact with the printing
screen 102.
[0041] In an embodiment, the direction 106 and the direction 110 can
be interchanged. As an example, the squeegee 104 may move in contact
with the printing screen 102, in the second direction 110, to apply the
conductor paste on the thin film sample and the flood bar 108 may move
in contact with the printing screen 102, in the first direction 106, to
accumulate the unused conductor paste.
[0042] In an embodiment, the printing screen 102 can be designed for
various patterns. As the screens are removable, the portable device 100
can be reused by replacing the printing screen 102.

[0043] In an embodiment, the movable arm 114 is in contact with the
rail assembly 112 using the intermediate arm 118. One end of the
intermediate arm 118 is pivotably in contact with the movable arm 114
and other end of the intermediate arm 118 is pivotably in contact with the
rail assembly 112.
[0044] In an embodiment, as the movable arm 114 traverses in
direction 116, the intermediate arm 118 moves the rail assembly in the
directions 106, 110.
[0045] In an embodiment, the movable arm 114 is connected to a push
button (not shown), wherein the push button is used to operate the
movable arm 114.
[0046] In an embodiment, the printing screen 102, the squeegee 104,
the flood bar 108, the rail assembly 112, the movable arm 114, the
intermediate arm 118 and the push button are prepared using CNC
machining.
[0047] In an embodiment, the portable device 100 is provided with an
air tight cap which prevents the conductor paste from drying. The portable
device 100 is very compact and is used to apply the conductor paste very
quickly.
TECHNICAL ADVANTAGE
[0048] The present disclosure proposes a device for applying conductor
paste on thin film samples.
[0049] The present disclosure further proposes a device for applying a
coating of the conductor paste in one touch with the help of guided support.

[0050] The present disclosure further proposes a device for controlling
the flow of conductor paste so that excess paste does not reach the
substrate.
[0051] The present disclosure further proposes a device to avoid
smearing of conductor pads.
[0052] The present disclosure further proposes a device for developing
high efficiency silicon solar cells.
[0053] Furthermore, each of the appended claims defines a separate
invention, which for infringement purposes is recognized as including
equivalents to the various elements or limitations specified in the claims.
Depending on the context, all references below to the “invention” may in
some cases refer to certain specific embodiments only. In other cases, it
will be recognized that references to the “invention” will refer to subject
matter recited in one or more, but not necessarily all, of the claims.
[0054] Groupings of alternative elements or embodiments of the
invention disclosed herein are not to be construed as limitations. Each group
member can be referred to and claimed individually or in any combination
with other members of the group or other elements found herein. One or
more members of a group can be included in, or deleted from, a group for
reasons of convenience and/or patentability. When any such inclusion or
deletion occurs, the specification is herein deemed to contain the group as
modified thus fulfilling the written description of all groups used in the
appended claims.
[0055] Furthermore, those skilled in the art can appreciate that the
terminology used herein is for the purpose of describing particular

embodiments only and is not intended to be limiting of the present
disclosure. It will be appreciated that several of the above-disclosed and
other features and functions, or alternatives thereof, may be combined into
other systems or applications. Various presently unforeseen or
unanticipated alternatives, modifications, variations, or improvements
therein may subsequently be made by those skilled in the art without
departing from the scope of the present disclosure as encompassed by the
following claims.
[0056] The claims, as originally presented and as they may be amended,
encompass variations, alternatives, modifications, improvements,
equivalents, and substantial equivalents of the embodiments and teachings
disclosed herein, including those that are presently unforeseen or
unappreciated, and that, for example, may arise from applicants/patentees
and others.
[0057] While the foregoing describes various embodiments of the
present disclosure, other and further embodiments of the present disclosure
may be devised without departing from the basic scope thereof. The scope
of the present disclosure is determined by the claims that follow. The
present disclosure is not limited to the described embodiments, versions or
examples, which are included to enable a person having ordinary skill in the
art to make and use the invention when combined with information and
knowledge available to the person having ordinary skill in the art.

WE CLAIM:
1. A portable device (100) for applying conductor paste on thin film
samples, the portable device (100) comprising:
a printing screen (102) configured to receive conductor paste;
a squeegee (104) arranged above the printing screen (102), wherein
the squeegee (104) is configured to:
spread the conductor paste on the printing screen (102) in a first
direction (106); and
force the conductor paste through the printing screen (102)
when the squeegee (104) is moved in contact with the printing
screen (102) in the first direction (106); and
a flood bar (108) arranged above the printing screen (102) and
adjacent to the squeegee (104), wherein the flood bar (102) is
configured to accumulate unused conductor paste when the flood bar
(102) is moved in contact with the printing screen (102) in a second
direction (110), wherein the second direction (110) is opposite to that
of the first direction (106).
2. The portable device (100) as claimed in claim 1, comprising a rail
assembly (112), wherein the squeegee (104) and the flood bar (108)
are configured to be received by the rail assembly (112) to move the
squeegee (104) and the flood bar (108) in the first direction (106) and
the second direction (110).
3. The portable device (100) as claimed in claim 2, comprising a movable
arm (114) configured to traverse along a third direction (116),
wherein,

the movable arm (114) is configured to move the rail assembly (112)
in the first direction (106) and the second direction (110); and
the third direction (116) is perpendicular to the first and second
directions (106, 110).
4. The portable device (100) as claimed in claim 3, comprising an
intermediate arm (118), wherein,
one end of the intermediate arm (118) is pivotably connected to the
movable arm (114);
other end of the intermediate arm (118) is pivotably connected to the
rail assembly (112); and
intermediate arm (118) is configured to translate movement of the
movable arm (114) in the third direction (116) to movement of the rail
assembly (112) in the first and second directions (106, 110).
5. The portable device (100) as claimed in claim 1, wherein the conductor
paste forced out from the printing screen (102) is applied on a thin
film sample placed below the printing screen (102).
6. The portable device (100) as claimed in claim 1, wherein the printing
screen (102) is made of polyester.
7. A method for applying conductor paste on thin film samples, the
method comprising:
receiving conductor paste using a printing screen (102);
spreading, using a squeegee (104), the conductor paste on the
printing screen (102) in a first direction (106), wherein the squeegee
(104) is arranged above the printing screen (102);

forcing the conductor paste through the printing screen (102), when
the squeegee (104) is moved in contact with the printing screen (102)
in the first direction (106); and
accumulating, using a flood bar (108), unused conductor paste when
the flood bar (102) is moved in contact with the printing screen (102)
in a second direction (110), wherein,
the flood bar (108) is arranged above the printing screen (102)
and adjacent to the squeegee (104); and
the second direction (110) is opposite to that of the first direction
(106).
8. The method as claimed in claim 7, comprising, using a rail assembly
(112), moving the squeegee (104) and the flood bar (108) in the first
direction (106) and the second direction (110), wherein the squeegee
(104) and the flood bar (108) are configured to be received by the rail
assembly (112)
9. The method as claimed in claim 8, comprising traversing a movable
arm (114) along a third direction (116), wherein,
the movable arm (114) is configured to move the rail assembly (112)
in the first direction (106) and the second direction (110); and
the third direction (116) is perpendicular to the first and second
directions (106, 110).

10. The method as claimed in claim 9, comprising translating, using an
intermediate arm (118), movement of the movable arm (114) in the
third direction (116) to movement of the rail assembly (112) in the
first and second direction (106, 110), wherein,
one end of the intermediate arm (118) is pivotably connected to the
movable arm (114); and
other end of the intermediate arm (118) is pivotably connected to the
rail assembly (112).
11. The method as claimed in claim 7, comprising applying the conductor
paste forced out from the printing screen (102) on a thin film sample
placed below the printing screen (102).
12. The method as claimed in claim 7, wherein the printing screen (102)
is made of polyester.