DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
This is an office action in response to Applicant’s arguments and remarks filed on 18 April 2026. Claims 1-16 are currently pending in the application. Claims 1-15 have been previously presented. Claim 16 is newly added. Claims 1-16 are being examined herein.
Status of Objections and Rejections
The rejection to claim 3 under 35 U.S.C. § 112(b) is withdrawn in view of the amendments.
The rejections to claims 6-14 under 35 U.S.C. § 112(b) are maintained.
The rejection to claims 1-5 under 35 U.S.C. § 102(a)(1) in view of Chun, et. al. (KR 20160064768 A) are maintained.
The rejection to claims 6-15 under 35 U.S.C. § 103 in view of Chun, et. al. (KR 20160064768 A) in view of Chung, et. al. (US 20050133101 A1) are maintained.
Response to Arguments
Applicant's arguments filed 18 April 2026 have been fully considered but they are not persuasive.
Applicant has presented the three arguments as listed below.
Argument 1: Rejection under 35 U.S.C. § 112(b):
Applicant argues the term "fluidic contact angle" is well understood in the art and having an angle that expands based on the fluidic contact angle is a definite structural limitation [Remarks, pg. 6, par. 05 - pg. 7, par. 03].
While examiner does agree the term "fluidic contact angle" is a well understood term and parameter in the art, no fluid to create said fluidic contact angle with the wall of the microfluidic device is positively recited in the claims. Examiner reminds Applicant the claim set it drawn to an apparatus, and while said fluidic contact angle is calculatable, without knowing the fluid, there is no limit on how to search for the angle of channel expansion; therefore, the metes and bounds of the claims are unclear.
Argument 2: Rejections under 35 U.S.C. § 102(a)(1)
Applicant argues the branched spiral channels do not teach a transition channel that split into a first and second channels [Remarks, pg. 7, par. 04 - pg. 8, par. 03].
Examiner points out that the is no limitation that the channels must remain straight, and therefore just because the branched channels of Chun have a spiral shape does not teach away from the requirements of the first and second channels of claim 1. Further, the only structural requirement of the transition channel is that it is between the first and second channels and that is expands in width as it approaches the branched second channels. The device of Chun teaches a singular channel expanding for a distance before becoming two physically separated channels [Fig. 6c].
Claim 16 is a new claim and therefore further search is required. More on claim 16 can be found below. However, Examiner notes that the walls are only defined to be divergent along a length of the transition path, but a center point from where that divergence begins is not defined. One of ordinary skill in the art could argue that from a center point of the flow path, the channel walls of Chun are divergent along the length of the transition channel from a central line in the fluid flow path.
Argument 3: Rejections under 35 U.S.C. § 103
Applicant argues neither alone nor in combination do Chun and Chung teach or suggest the claimed invention [Remarks, pg. 8, par. 05 - pg. 9, par. 04].
Applicant is reminded that these claims are drawn to an apparatus; therefore, the manner of operating a disclosed device is given no patentable weight. While Chung only teaches the expansion into a single channel, Chung teaches the angle at which the channel expands influences the positive capillary pressure at an expanding channel to promote forward fluid flow through the channel. Chung ultimately teaches the capillary force value of the channel is partially influenced by the angle at which the channel expands [Chung, par. 0052-0053].
Claim Interpretation
Examiner notes that claims 6-15 all rely on a fluidic contact angle of an unspecified fluid in a microfluidic channel of an unspecified material. Further, the fluid within the channel is not a positively recited claim element and therefore does not carry patentable weight in an apparatus claim. Examiner notes because the microfluidic device of Chun, et. al. ((KR 20160064768 A) teaches the structural elements of claim 1 (described in detail below), it is fully capable of having the dimensions as applied in claims 6-15 that are ultimately based the intended use of the microfluidic device with an unspecified fluid having a fluidic contact angle.
In favor of compact prosecution, examiner has included additional examination of the claims in view of Chun, et. al. (KR 20160064768 A) in view of Chung, et. al. (US 20050133101 A1) in order to arrive that the same structural elements as defined by the intended use of the microfluidic device with an unspecified fluid having a fluidic contact angle.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 6-14 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 6 recites the limitation "a fluidic contact angle" in lines 3-4 of the claim. Examiner notes fluidic contact angles are determined based on a plurality of factors, and Applicant themselves points in paragraph 0021 of the specification of the instant application the same fact. Because no specific fluid or specific material is recited or positively claimed, the scope of the claim remains indefinite because there is an indefinite combination of fluids and materials all of which will contribute to a slightly different fluidic contact angle.
Claim 7 is rejected based on its dependency to claim 6.
Claim 8 recites the limitation "a fluidic contact angle" in line 6 of the claim. Examiner notes fluidic contact angles are determined based on a plurality of factors, and Applicant themselves points in paragraph 0021 of the specification of the instant application the same fact. Because no specific fluid or specific material is recited or positively claimed, the scope of the claim remains indefinite because there is an indefinite combination of fluids and materials all of which will contribute to a slightly different fluidic contact angle.
Claims 9-13 are rejected based on their dependency to claim 8.
Claim 11 recites the limitation " wherein the positive first term and the negative first term " in lines 3-4 of the claim. Examiner believes this should recite “… and the negative second term” as no negative first term has been previously recited. Examiner will examine the claim as such.
Claim 12 recites the limitation "a fluidic contact angle" in lines 3-4 and 6 of the claim. Examiner notes fluidic contact angles are determined based on a plurality of factors, and Applicant themselves points in paragraph 0021 of the specification of the instant application the same fact. Because no specific fluid or specific material is recited or positively claimed, the scope of the claim remains indefinite because there is an indefinite combination of fluids and materials all of which will contribute to a slightly different fluidic contact angle.
Claim 13 recites the limitation "a fluidic contact angle" in line 3 of the claim. Examiner notes fluidic contact angles are determined based on a plurality of factors, and Applicant themselves points in paragraph 0021 of the specification of the instant application the same fact. Because no specific fluid or specific material is recited or positively claimed, the scope of the claim remains indefinite because there is an indefinite combination of fluids and materials all of which will contribute to a slightly different fluidic contact angle.
Claim 14 recites the limitation "a fluidic contact angle" in line 9 of the claim. Examiner notes fluidic contact angles are determined based on a plurality of factors, and Applicant themselves points in paragraph 0021 of the specification of the instant application the same fact. Because no specific fluid or specific material is recited or positively claimed, the scope of the claim remains indefinite because there is an indefinite combination of fluids and materials all of which will contribute to a slightly different fluidic contact angle.
Claim Rejections - 35 USC § 102
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-5 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Chun, et. al. (KR 20160064768 A; citations made with respect to attached English machine translation and original document).
Regarding claim 1, Chun teaches a microfluidic device with a main channel that branches to side channels [par. 0001]. Chun teaches a microfluidic device comprising a first channel (see the area with the box of provided Fig. 6c below), a plurality of second channels 10, 40, and a transition channel (see the area between the two arrows in provided Fig. 6c below) splitting the first channel into the second channels 10, 40, the transition channel having a first end (see left arrow in provided Figure 6c below) fluidically connected to the first channel and a second end (see left arrow in provided Figure 6c below) fluidically connected to the second channels 10, 40 [Fig. 6c]. Chun teaches wherein the transition channel expands in width from a width of the first channel at the first end to no less than a sum of widths of the second channels at the second end as seen by each of the outer walls of the first channel continuing to each become an outer wall in the second channels as seen in Fig. 6c.
Examiner notes the limitation so as to promote fluid flow from the first channel to the second channels is drawn to a functional limitation of the expanding and branching channel, and because Chun teaches a transition channel 17 that expands from a first end to a branching second end the transition channel 17 is functionally capable to promote fluid flow from the first channel to the second channels.
PNG
media_image1.png
465
531
media_image1.png
Greyscale
Regarding claim 2, Chun teaches the microfluidic device further comprises a split wedge separating adjacent of the second channels at the second end of the transition channel (as seen by the right-most arrow in provided Fig. 6c above).
Regarding claim 3, Chun teaches wherein the transition channel is a first transition channel, and the microfluidic device further comprising a plurality of third channels (see branching at end of channel 40 leading to 433, 434) connected by a second transition channel 435 splitting a selected second channel 40 into the third channels 433, 434 [Fig. 5, 6c; par. 0052]. Chun teaches the second transition channel 435 having a first end (furthest away from the branch) fluidically connected to the selected second channel 40 and having a second end (closest to the branch) fluidically connected to the third channels 433. 434 [Fig. 5, 6c]. Chun further teaches wherein the second transition channel 435 expands in width from the width of the selected second channel 40 at the first end to no less than a sum of widths of the third channels 433, 434 at the second end as seen in the channel extended beyond the dashed line 400 in Fig. 5. Chun further teaches that the width of branch 435 is larger than the width of channel 40 and third channels 433, 434 are a minimum of 0.6 times the width of channel 40 and when added together that means the sum of the third channels 433, 434 is not less than that of the second channel 40 [par. 0052]
Examiner notes the limitation so as to promote fluid flow from the second channel to the third channels is drawn to a functional limitation of the expanding and branching channel, and because Chun teaches a transition channel 12 that expands from a first end to a branching second end the transition channel 12 is functionally capable to promote fluid flow from the second channel to the third channels.
Regarding claim 4, Chun teaches wherein the transition channel asymmetrically splits the first channel into the second channels as seen by the one of the second channels 10 continuing linearly and a second channel 40 moving away from the main linear pathway [Fig. 6c].
Regarding claim 5, Chun teaches wherein the width of the first channel and the widths of the second channels are equal to one another as seen by second channel 10 aligning with the first channel and Chun additionally states second channel 40 is equal to the width of the main channel [par. 0033].
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 6-16 are rejected under 35 U.S.C. 103 as being unpatentable over Chun, et. al. (KR 20160064768 A; citations made with respect to attached English machine translation and original document) as applied to claim 1, in view of Chung, et. al. (US 20050133101 A1).
Regarding claim 6, Chun teaches wherein the transition channel linearly expands in width from the width of the first channel to the sum of the widths of the second channels at an angle as seen by the linear extension of the first channel to the second channel 10 through the transition channel (see the top line/wall of channel 10 continuing in a straight line) and the bottom line/wall is extended downward at an angle as the first channel transforms into the transition channel and finally to the second channel 40 [Fig. 6c].
Chun is silent to the angle being no greater than two times a difference between 90 degrees and a fluidic contact angle.
Chung teaches a fluid control device and method for the control of fluid through microfluidic channels based on capillary forces (Abstract). Chung teaches a device wherein channel 120 expands in width to from reaction chamber 110 solely through the capillary action of the fluid interacting with the surface of the microfluidic channel [Fig. 1B; par. 0036, 0042, 0046] (linearly expands in width at an angle). Chung further teaches the flow is further influenced by the shape of the fluid droplet that creates a contact angle with the solid surface of the microchannel [par. 0048]. Going forward, the contact angle of the droplet with respect to the solid surface will be represented by ϴ. Chung teaches ϴ is influenced by a plurality of factors including but not limited to the material of the surface and geometry of the single or multiple surfaces [Fig. 2A-D; par. 0048-0050]. Chung teaches when a channel expands, as seen in Fig. 3A by an angle of β, there is a change in capillary force [par. 0051-0054]. When turning to Fig. 3C, Chung teaches wherein as the ϴ changes, in order for the capillary force to remain positive and thus move the fluid forward in the microfluidic device the β is no greater than two times a difference between 90 degrees and a fluidic contact angle [Fig. 3c; par. 0054-0056]. An example as taught by Chung in Fig. 3C shows a fluid with a contact angle ϴ equal to 80 needing to have an expansion angle β of at least 20 degrees or less to maintain a positive capillary force to drive the fluid forward in the expanded channel. Chung teaches the angle at which the channel expands is in part impacted by the contact angle and in order to keep fluid moving forward under capillary pressure alone, the expansion angle must be determined based on the fluid contact angle [par. 0052-0053].
It would have been obvious for one of ordinary skill in the art before the effective filing date of the invention to modify the angle of the expanded channel of Chun to follow the principles set forth by Chung in order to keep the capillary pressure positive and continue to move the liquid forward in the microfluidic system without applying external pressure. Because both systems use capillary forces to move liquid through an expanding microfluidic channel modifying the angle of expansion as provided by Chung, provides likewise sought functionality with reasonable expectation of success. MPEP 2143(I)(G).
Regarding claim 7, Modified Chun in view of Chung teaches in Fig. 3C [Chung, Fig. 3C] shows a fluid with a contact angle ϴ equal to 80 needing to have the angle is no greater than 20 degrees to maintain a positive capillary force to drive the fluid forward in the expanded channel.
Regarding claim 8, Chun teaches wherein the transition channel linearly expands in width from the width of the first channel to the sum of the widths of the second channels at an increasing angle as seen by the linear extension of the first channel to the second channel 10 through the transition channel (see the top line/wall of channel 10 continuing in a straight line) and the bottom line/wall is extended downward at an angle as the first channel transforms into the transition channel and finally to the second channel 40 [Fig. 6c].
Chun is silent to the increasing angle being based on a fluidic contact angle.
Chung teaches a fluid control device and method for the control of fluid through microfluidic channels based on capillary forces (Abstract). Chung teaches a device wherein channel 120 expands in width to from reaction chamber 110 solely through the capillary action of the fluid interacting with the surface of the microfluidic channel [Fig. 1B; par. 0036, 0042, 0046] (linearly expands in width at an angle). Chung further teaches the flow is further influenced by the shape of the fluid droplet that creates a contact angle with the solid surface of the microchannel [par. 0048]. Going forward, the contact angle of the droplet with respect to the solid surface will be represented by ϴ. Chung teaches ϴ is influenced by a plurality of factors including but not limited to the material of the surface and geometry of the single or multiple surfaces [Fig. 2A-D; par. 0048-0050]. Chung teaches when a channel expands, as seen in Fig. 3A by an angle of β, there is a change in capillary force [par. 0051-0054]. When turning to Fig. 3C, Chung teaches wherein as the ϴ changes, in order for the capillary force to remain positive and thus move the fluid forward in the microfluidic device the β must be based on a fluidic contact angle [Fig. 3c; par. 0054-0056]. Chung teaches the angle at which the channel expands is in part impacted by the contact angle and in order to keep fluid moving forward under capillary pressure alone, the expansion angle must be determined based on the fluid contact angle [par. 0052-0053].
It would have been obvious for one of ordinary skill in the art before the effective filing date of the invention to modify the angle of the expanded channel of Chun to follow the principles set forth by Chung in order to keep the capillary pressure positive and continue to move the liquid forward in the microfluidic system without applying external pressure. Because both systems use capillary forces to move liquid through an expanding microfluidic channel modifying the angle of expansion as provided by Chung, provides likewise sought functionality with reasonable expectation of success. MPEP 2143(I)(G).
Regarding claim 9, Modified Chun in view of Chung teaches when a channel expands, as seen in Fig. 3A by an angle of β, there is a change in capillary force [par. 0051-0054]. When turning to Fig. 3C, Chung teaches wherein the contact angle ϴ changes, the increasing angle (β) maintains a specified positive net capillary fluidic force along a length of the transition channel [Fig. 3c; par. 0054-0056]. Chung teaches the angle at which the channel expands is in part impacted by the contact angle and in order to keep fluid moving forward under capillary pressure alone, the expansion angle must be determined based on the fluid contact angle [par. 0052-0053].
Regarding claim 10, Modified Chun in view of Chung teaches in addition to expansion angle, the length of the increasing (or decreasing) channel must also be considered and properly combined [Chung, par. 0074].
Modified Chun is silent to wherein the increasing angle minimizes the length of the transition channel along which the transition channel expands in width.
Chung teaches ultimately what drives fluid forward in a microfluidic channel is based on an overall positive capillary force value as seen in Fig. 3B and 3C [par. 0069]. This means height, width, change of width (increasing or decreasing angle), and length of the channel amongst other variables influence that overall net positive capillary force that drive the fluid forward [par. 0069-0074]. Chung teaches wherein a channel width decreases the length of the channel must increase [par. 0074].
Therefore, Chung teaches wherein the channel length is a result-effective variable. Specifically, Chung teaches angle at which the channel increases or decreases will ultimately influence the length of the channel [par. 0074]. Since this particular parameter is recognized as a result-effective variable (i.e. a variable which achieves a recognized result), the determination of the optimum or workable ranges of said variable can be characterized as routine experimentation. See MPEP 2144.05 (II)(A). Therefore, it would have been obvious to one having ordinary skill in the art prior to the effective filing date of the claimed invention to minimizes the length of the transition channel along which the transition channel expands in width.
Regarding claim 11, Modified Chun in view of Chung teaches when a channel expands, as seen in Fig. 3A by an angle of β, there is a change in capillary force [Chung, par. 0051-0054]. When turning to Fig. 3C [Chung], Chung teaches wherein the contact angle ϴ changes, the increasing angle (β) is determined to maintain a specified positive net capillary fluidic force [Chung, Fig. 3c; par. 0054-0056]. Chung teaches the angle at which the channel expands is in part impacted by the contact angle and in order to keep fluid moving forward under capillary pressure alone, the expansion angle must be determined based on the fluid contact angle as well as height and width of the channel [Chung, par. 0051-0055]. Specifically Chung teaches Equation 1 and Equation 2 for the expansion of the channel along a width (Eqn. 1) while considering and upper and lower surface (Eqn. 2) wherein the specified positive net capillary fluidic force is based on a positive first term contributed by a floor and a ceiling of the transition channel between sidewalls of the transition channel, as seen represented by the term containing W in Eqn. 1 and 2, and negative second term contributed by the sidewalls of the transition channel between the floor and the ceiling of the transition channel, as seen represented by the term containing H in Eqn. 1 and 2 [Chung, par. 0051-0055]. Further Chung teaches wherein the positive first term and the negative first term are each further based on fluidic surface tension as seen by both terms in the equation being treated by surface tension coefficient of the fluid, represented by σ [Chung, par. 0051-0055]. As seen in Fig. 3B and 3C of Chung, each individual value is fine tuned to create an overall net positive the influence a forward flow [Chung, par. 0056].
PNG
media_image2.png
131
910
media_image2.png
Greyscale
PNG
media_image3.png
98
772
media_image3.png
Greyscale
Regarding claim 12, Modified Chun in view of Chung teaches when a channel expands, as seen in Fig. 3A by an angle of β, there is a change in capillary force [Chung, par. 0051-0054]. When turning to Fig. 3C [Chung], Chung teaches wherein the contact angle ϴ changes, the increasing angle (β) is determined to maintain a specified positive net capillary fluidic force [Chung, Fig. 3c; par. 0054-0056]. Chung teaches the angle at which the channel expands is in part impacted by the contact angle and in order to keep fluid moving forward under capillary pressure alone, the expansion angle must be determined based on the fluid contact angle as well as height and width of the channel [Chung, par. 0051-0055]. Specifically Chung teaches Equation 1 and Equation 2 for the expansion of the channel along a width (Eqn. 1) while considering and upper and lower surface (Eqn. 2) wherein the specified positive net capillary fluidic force is based on a positive first term and a negative second term, wherein the positive first term is based on a width of the transition channel and the fluidic contact angle, as seen represented by the term containing W and ϴ (contact angle) in Eqn. 1 and 2, wherein the negative second term is based on a height of the transition channel, the fluidic contact angle, and the increasing angle at which the transition channel non-linearly expands in width, as seen represented by the term containing H and ϴ (contact angle) and β (increasing angle) in Eqn. 1 and 2 [Chung, par. 0051-0055]. Further Chung teaches wherein the positive first term and the negative first term are each further based on fluidic surface tension as seen by both terms in the equation being treated by surface tension coefficient of the fluid, represented by σ [Chung, par. 0051-0055]. As seen in Fig. 3B and 3C of Chung, each individual value is fine tuned to create an overall net positive the influence a forward flow [Chung, par. 0056].
Regarding claim 13, Modified Chun in view of Chung teaches Equations 1 and 2 define the capillary forces that influence movement of the fluid through the expanding channel wherein as long as the overall pressure remains positive, there will be a forward fluid flow [par. 0054]. Chung teaches as seen in the Equations 1 and 2 that surface tension (σ), fluidic contact angle (ϴ), and increasing angle (β) all influence the overall positive pressure along with the channel height (H) and width (W) [Chung, par. 0051-0055].
Modified Chun in view of Chung is silent to wherein the specified positive net capillary fluidic force is equal to
2
γ
w
cos
θ
+
h
cos
θ
θ
+
ϕ
2
.
Chung teaches ultimately what drives fluid forward in a microfluidic channel is based on an overall positive capillary force value as seen in Fig. 3B and 3C [par. 0069]. This means height, width, increasing angle, surface tension, and contact angle amongst other variables influence that overall net positive capillary force that drive the fluid forward [par. Fig. 3A-C; 0051-0055]. Further, Equations 1 and 2 of Chung teach a change in the pressure of the capillary forces and not the force of the fluid itself is experiencing. Because force and pressure are related values, an overall positive pressure as taught by Chung to keep the fluid moving forward means and overall positive force is also needed (since an area will always be positive).
Therefore, Chung teaches wherein the pressure and therefore the force is a result-effective variable. Specifically, Chung teaches a pressure, and by relation force, is influenced by height, width, surface tension, contact angle, and increasing angle as per the pressure equations 1 and 2 [par. 0051-0055]. Since this particular parameter is recognized as a result-effective variable (i.e. a variable which achieves a recognized result), the determination of the optimum or workable ranges of said variable can be characterized as routine experimentation. See MPEP 2144.05 (II)(A). Therefore, it would have been obvious to one having ordinary skill in the art prior to the effective filing date of the claimed invention to take Equations 1 and 2 along with the relevant variables associated with equations 1 and 2 to arrive at the claimed equations wherein the specified positive net capillary fluidic force is equal to
2
γ
w
cos
θ
+
h
cos
θ
θ
+
ϕ
2
.
Regarding claim 14, Chun teaches a microfluidic device with a main channel that branches to side channels [par. 0001]. Chun teaches a microfluidic device comprising a first channel (see the area with the box of provided Fig. 6c below), a plurality of second channels 10, 40, and a transition channel (see the area between the two arrows in provided Fig. 6c below) splitting the first channel into the second channels 10, 40, the transition channel having a first end (see left arrow in provided Figure 6c below) fluidically connected to the first channel and a second end (see left arrow in provided Figure 6c below) fluidically connected to the second channels 10, 40 [Fig. 6c].
Chun teaches wherein the transition channel linearly expands in width from the width of the first channel to the sum of the widths of the second channels at an angle as seen by the linear extension of the first channel to the second channel 10 through the transition channel (see the top line/wall of channel 10 continuing in a straight line) and the bottom line/wall is extended downward at an angle as the first channel transforms into the transition channel and finally to the second channel 40 [Fig. 6c].
Chun is silent to the angle being no greater than two times a difference between 90 degrees and a fluidic contact angle.
PNG
media_image1.png
465
531
media_image1.png
Greyscale
Chung teaches a fluid control device and method for the control of fluid through microfluidic channels based on capillary forces (Abstract). Chung teaches a device wherein channel 120 expands in width to from reaction chamber 110 solely through the capillary action of the fluid interacting with the surface of the microfluidic channel [Fig. 1B; par. 0036, 0042, 0046] (linearly expands in width at an angle). Chung further teaches the flow is further influenced by the shape of the fluid droplet that creates a contact angle with the solid surface of the microchannel [par. 0048]. Going forward, the contact angle of the droplet with respect to the solid surface will be represented by ϴ. Chung teaches ϴ is influenced by a plurality of factors including but not limited to the material of the surface and geometry of the single or multiple surfaces [Fig. 2A-D; par. 0048-0050]. Chung teaches when a channel expands, as seen in Fig. 3A by an angle of β, there is a change in capillary force [par. 0051-0054]. When turning to Fig. 3C, Chung teaches wherein as the ϴ changes, in order for the capillary force to remain positive and thus move the fluid forward in the microfluidic device the β is no greater than two times a difference between 90 degrees and a fluidic contact angle [Fig. 3c; par. 0054-0056]. An example as taught by Chung in Fig. 3C shows a fluid with a contact angle ϴ equal to 80 needing to have an expansion angle β of at least 20 degrees or less to maintain a positive capillary force to drive the fluid forward in the expanded channel. Chung teaches the angle at which the channel expands is in part impacted by the contact angle and in order to keep fluid moving forward under capillary pressure alone, the expansion angle must be determined based on the fluid contact angle [par. 0052-0053].
It would have been obvious for one of ordinary skill in the art before the effective filing date of the invention to modify the angle of the expanded channel of Chun to follow the principles set forth by Chung in order to keep the capillary pressure positive and continue to move the liquid forward in the microfluidic system without applying external pressure. Because both systems use capillary forces to move liquid through an expanding microfluidic channel modifying the angle of expansion as provided by Chung, provides likewise sought functionality with reasonable expectation of success. MPEP 2143(I)(G).
Regarding claim 15, Chun teaches a microfluidic device with a main channel that branches to side channels [par. 0001]. Chun teaches a microfluidic device comprising a first channel (see the area with the box of provided Fig. 6c above), a plurality of second channels 10, 40, and a transition channel (see the area between the two arrows in provided Fig. 6c above) splitting the first channel into the second channels 10, 40, the transition channel having a first end (see left arrow in provided Figure 6c above) fluidically connected to the first channel and a second end (see left arrow in provided Figure 6c above) fluidically connected to the second channels 10, 40 [Fig. 6c].
Chun teaches wherein the transition channel linearly expands in width from the width of the first channel to the sum of the widths of the second channels at an increasing angle as seen by the linear extension of the first channel to the second channel 10 through the transition channel (see the top line/wall of channel 10 continuing in a straight line) and the bottom line/wall is extended downward at an angle as the first channel transforms into the transition channel and finally to the second channel 40 [Fig. 6c].
Chun is silent to an increasing angle maintains a specified positive net capillary fluidic force along a length of the transition channel.
Chung teaches a fluid control device and method for the control of fluid through microfluidic channels based on capillary forces (Abstract). Chung teaches a device wherein channel 120 expands in width to from reaction chamber 110 solely through the capillary action of the fluid interacting with the surface of the microfluidic channel [Fig. 1B; par. 0036, 0042, 0046] (linearly expands in width at an angle). Chung further teaches the flow is further influenced by the shape of the fluid droplet that creates a contact angle with the solid surface of the microchannel [par. 0048]. Going forward, the contact angle of the droplet with respect to the solid surface will be represented by ϴ. Chung teaches ϴ is influenced by a plurality of factors including but not limited to the material of the surface and geometry of the single or multiple surfaces [Fig. 2A-D; par. 0048-0050]. Chung teaches when a channel expands, as seen in Fig. 3A by an angle of β, there is a change in capillary force [par. 0051-0054]. When turning to Fig. 3C, Chung teaches wherein the contact angle ϴ changes, the increasing angle (β) maintains a specified positive net capillary fluidic force along a length of the transition channel [Fig. 3c; par. 0054-0056]. Chung teaches the angle at which the channel expands is in part impacted by the contact angle and in order to keep fluid moving forward under capillary pressure alone, the expansion angle must be determined based on the fluid contact angle [par. 0052-0053].
It would have been obvious for one of ordinary skill in the art before the effective filing date of the invention to modify the angle of the expanded channel of Chun to follow the principles set forth by Chung in order to keep the capillary pressure positive and continue to move the liquid forward in the microfluidic system without applying external pressure. Because both systems use capillary forces to move liquid through an expanding microfluidic channel modifying the angle of expansion as provided by Chung, provides likewise sought functionality with reasonable expectation of success. MPEP 2143(I)(G).
Regarding claim 16, Chun teaches wherein the transition channel has a singular sidewall that diverges along the length of the transition channel.
Chun, however, is silent to both sidewalls diverging, specifically, wherein the transition channel has diverging sidewalls along a length of the transition channel defined between the first end and the second end.
ng teaches a fluid control device and method for the control of fluid through microfluidic channels based on capillary forces (Abstract). Chung teaches a device wherein channel 120 expands in width to from reaction chamber 110 solely through the capillary action of the fluid interacting with the surface of the microfluidic channel [Fig. 1B; par. 0036, 0042, 0046]. Chung teaches the expansion of a channel can take on a plurality of shapes; a non-extensive list can be seen in Figure 4 [par. 0057]. As seen in Figure 3A and in the second depiction in the top row of Figure 4, Chun teaches wherein the expansion of the channel occurs through the two walls diverging from the center, dashed line (wherein the transition channel has diverging sidewalls along a length of the transition channel defined between the first end and the second end). Chung further teaches the flow is further influenced by the shape of the fluid droplet that creates a contact angle with the solid surface of the microchannel [par. 0048] and that interaction further extends to when the channel expands [Fig. 3A-C; par. 0051-0056]. Chung teaches the angle at which the channel expands is in part impacted by the contact angle and in order to keep fluid moving forward under capillary pressure alone, the expansion angle must be determined based on the fluid contact angle [par. 0052-0053].
It would have been obvious for one of ordinary skill in the art before the effective filing date of the invention to modify direction of the branching channels of Chun to comprise diverging sidewalls from the first channel as taught by Chung because doing so contributes to the capillary force that promotes fluid movement in the channel in addition to the fluidic contact angle [Chung, par. 0052-0053) with reasonable expectation of success. MPEP 2143(I)(G).
Further, there is only a finite way for a singular channel to expand to turn into two branching channels and it would have been obvious for one of ordinary skill in the art before the effective filing date of the invention to modify the diverging direction of the channel of Chun to have each wall diverge in two, opposite directions from a center line as taught by Chun because that expansion angle contributes to the driving capillary force [Chun, par. 0052-0053]. Because the channel walls can expand in only but so many different directions, it would be obvious to try expanding the first channel through two diverging walls to create a transition channel before branching into at least two second channels as taught by Chun in order to influence capillary force with reasonable expectation of success. MPEP 2143(I)(E).
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MADISON T HERBERT whose telephone number is (571)270-1448. The examiner can normally be reached Monday-Friday 8:30a-5:00p.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Maris Kessel can be reached at (571) 270-7698. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/M.T.H./Examiner, Art Unit 1758
/MARIS R KESSEL/Supervisory Patent Examiner, Art Unit 1758
Prosecution Insights