U.S. patent application number 17/172459 was filed with the patent office on 2021-06-03 for microfluidics system.
This patent application is currently assigned to HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.. The applicant listed for this patent is HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.. Invention is credited to Chantelle Domingue, Manish Giri, Matthew David Smith.
Application Number | 20210162407 17/172459 |
Document ID | / |
Family ID | 1000005389515 |
Filed Date | 2021-06-03 |
United States Patent
Application |
20210162407 |
Kind Code |
A1 |
Smith; Matthew David ; et
al. |
June 3, 2021 |
MICROFLUIDICS SYSTEM
Abstract
Provided herein are a system and method for using a
microfluidics device. The system includes: a plurality of pumps and
a plurality of sensors; a first communication line to select a pump
from the plurality of pumps and select a sensor from the plurality
of sensors; a second communication line selectively connected to
the selected pump; and a third communication line selectively
connected to the selected sensor.
Inventors: |
Smith; Matthew David;
(Corvallis, OR) ; Giri; Manish; (Corvallis,
OR) ; Domingue; Chantelle; (Palo Alto, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P. |
Spring |
TX |
US |
|
|
Assignee: |
HEWLETT-PACKARD DEVELOPMENT
COMPANY, L.P.
Spring
TX
|
Family ID: |
1000005389515 |
Appl. No.: |
17/172459 |
Filed: |
February 10, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15748535 |
Jan 29, 2018 |
10946379 |
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PCT/US2016/015622 |
Jan 29, 2016 |
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17172459 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01L 2300/0627 20130101;
G16H 40/63 20180101; B01L 2300/0867 20130101; G16H 50/20 20180101;
B01L 2400/0442 20130101; B01L 3/50273 20130101; B01L 2300/0864
20130101; C12M 23/16 20130101; G11C 19/28 20130101 |
International
Class: |
B01L 3/00 20060101
B01L003/00; C12M 3/06 20060101 C12M003/06; G16H 40/63 20060101
G16H040/63; G16H 50/20 20060101 G16H050/20 |
Claims
1. A method of making microfluidics measurements, the method
comprising: using a single communication line, selecting a sensor
from a plurality of sensors and a pump from a plurality of pumps;
activating the selected pump; and obtaining a sensor measurement
from the selected sensor during the activation of the selected
pump.
2. The method of claim 1, wherein the pump is a bubble pump.
3. The method of claim 1, further comprising, with the selected
pump, receiving an activation sequence that varies based on the
selected sensor.
4. The method of claim 1, wherein selection of a first sensor
automatically selects a corresponding first pump.
5. The method of claim 1, further comprising serially operating the
single communication line to select the sensor from the plurality
of sensors and the pump from the plurality of pumps.
6. The method of claim 1, further comprising using a plurality of
transistors connected to the single communication line to activate
the selected pump and enable the selected sensor.
7. The method of claim 1, wherein activating the selected pump
further comprises receiving a signal on a second communication line
with branches that connect to each pump in the plurality of pumps
such that the signal on the second communication line operates the
selected pump.
8. The method of claim 7, with a third communication line with
branches that connect to each sensor in the plurality of sensors,
transmitting output of the selected sensor on the third
communication line.
9. The method of claim 7, further comprising receiving a signal to
drive the selected pump through a single connection pad at which
the second communication line terminates.
10. The method of claim 8, further comprising outputting a signal
from the selected sensor to a single connection pad at which the
third communication line terminates.
11. A method of making microfluidics measurements in a
microfluidics system that comprises a plurality of pumps and a
plurality of sensors, the method comprising: with a first
communication line, selecting a pump from the plurality of pumps
and a sensor from the plurality of sensors, the first communication
line connected to a plurality of transistors that are connected to
selectively enable operation of the selected pump and selected
sensor in response to a signal on the first communication line;
operating the selected pump with a signal on a second communication
line with branches that connect to each pump in the plurality of
pumps such that a signal on the second communication line operates
the selected pump selectively enabled through the plurality of
transistors; and transmitting output of the selected sensor on a
third communication line with branches that connect to each sensor
in the plurality of sensors.
12. The method of claim 11, further comprising simultaneously
enabling multiple pumps from the plurality of pumps in response to
a selection signal on the first communication line.
13. The method of claim 11, selectively enabling both a first pump
and a first sensor based on a state of a first transistor. wherein
the first transistor amongst the plurality of transistors is
connected to both the first pump of the plurality of pumps and the
first sensor of the plurality of sensors.
14. The method of claim 11, further comprising, with a plurality of
flip-flops connected to the plurality of transistors, upon receipt
of a clock signal, transferring a state of a first transistor to a
next transistor in the plurality of transistors.
15. The method of claim 14, further comprising having a greater
number of flip-flops in the plurality of flip-flops than
transistors in the plurality of transistors.
16. The method of claim 14, wherein each transistor in the
plurality of transistors has a gate connected to a different
flip-flop in the plurality of flip-flops.
17. A method of making microfluidics measurements, the method
comprising: inputting a selection signal to a single communication
line, the selection signal selecting and enabling a sensor from a
plurality of sensors and a pump from a plurality of pumps;
operating the selected pump to move fluid; and obtaining a sensor
signal measuring a parameter of the fluid from the selected sensor
during the operation of the selected pump; and outputting the
sensor signal from the selected sensor.
18. The method of claim 17, further comprising, with the selected
pump, receiving an activation sequence that varies based on the
selected sensor.
19. The method of claim 17, wherein selection of a first sensor
automatically selects a corresponding first pump.
20. The method of claim 17, further comprising serially operating
the single communication line to select the sensor from the
plurality of sensors and the pump from the plurality of pumps.
Description
BACKGROUND
[0001] Microfluidics test methods are seeing increasing development
to provide point of care (POC) testing. Point of care focuses on
providing diagnostic or other testing services at the site of
sample collection. For medical testing, this allows the test
results to be provided while the medical personnel and the patient
are still together, avoiding a second visit and allowing immediate
commencement of appropriate treatment. It avoids the delay in
waiting for test results or the risk of beginning the potentially
wrong treatment in the absence of a diagnosis.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] The accompanying drawings illustrate various examples of the
principles described herein and are a part of the specification.
The illustrated examples are intended to describe examples and do
not limit the scope of the claims. Like numerals denote similar but
not necessarily identical elements.
[0003] FIG. 1 shows an example system consistent with this
specification.
[0004] FIG. 2 shows an example system consistent with this
specification.
[0005] FIG. 3 shows an example system consistent with this
specification.
[0006] FIG. 4 shows an example method consistent with this
specification.
[0007] FIG. 5 shows an example system consistent with this
specification.
DETAILED DESCRIPTION
[0008] Point of care tests face additional demands over lab based
tests. In POC testing, components may need to be shelf stable. In
contrast, labs may use reagents that use refrigeration, freezing,
or other special storage conditions. POC testing equipment may need
to be portable. In contrast, lab equipment may be larger. Ideally,
the testing is available to the same number of patients, which in
turn, implies more testing devices compared with a single lab
setup. Testing procedures may need to be simplified to allow
patient contacting medical professionals to reliably and
reproducibly obtain results. In contrast, labs often employ
specialists to perform testing.
[0009] One advantage POC tests have is that there is often a short
time between sample acquisition and testing. This may avoid the
need for specialized handling and shipping procedures (e.g. ice
packs) to avoid sample degradation. POC samples also may be less
vulnerable to contamination or mix-up during handling because the
sample may be acquired and processed by the same individual without
other samples in the vicinity. However, despite these advantages,
the technical and economic advantages of traditional lab base
approaches represent a significant challenge to new POC tests.
[0010] Accordingly, development of POC devices and test methods
focuses on developing reliable, robust tests performable at
reasonable cost at the point of care. In the end, increased cost of
the POC method over a lab-based test balances against the benefit
of the medical benefits of reduced time for the medical provider to
obtain results.
[0011] Microfluidics testing generally refers to performing testing
on small volumes of fluid, generally in the nanoliter (nl) to
picoliter (pl) range. The test sample is often extracted from a
larger sample, for example in the microliter (pl) or milliliter
(ml) range. For medical tests, small samples can often be acquired
with less pain and/or injury to a patient. The small sample volumes
also allow multiple tests to be performed on a single sample. In
some cases, these include different kinds of tests performed
simultaneously or sequentially on a microfluidics device. In other
cases, they include replicates, including true replicates and time
series replicates. The small size of the hardware involved often
makes it practical to perform replicate measurements without
additional material or time cost. This can improve the reliability
of the test by averaging the results of multiple runs. As discussed
below, the methods described in this specification may facilitate
performing multiple tests using a single chip and/or cartridge
without significant impacting the chip/cartridge cost.
[0012] While a variety of different models exist for performing
microfluidics tests, one model may offer some advantages. In this
model, the test system is divided into two components, the device
and the cartridge. The device is a reusable component that is used
for multiple tests. Often times the device is larger than the
cartridge. The device may include a processor and other electronic
components to control and regulate the activities on the cartridge.
The device may include a memory and communication ports or systems.
In some examples, the device is handheld. In most examples, the
device is compact and portable. The device may be considered a
durable medical device.
[0013] The cartridge is a component used to support or enable the
device to perform the desired test. The device may support many
kinds of cartridges or a single type. The cartridge is often
disposable. However, cartridges can be recycled, refurbished,
reconditioned, and/or reloaded depending on the economics and
healthcare safety of reuse vs. make new. The cartridge interfaces
with the device. While this often takes the form of a physical
connection with electrical contacts, it can also be performed using
a wireless connection, such as Bluetooth, WI-Fi, or other local
communication method. The goal of the cartridge is to reduce the
costs of the cartridge while enabling the cartridge to enable the
desired microfluidics method. This lowers the per test cost.
Accordingly, the cartridge may have a minimal number of electronics
components, especially when those functions can be provided by the
device. In contrast, the cartridge generally does contain the
materials to perform the specific test, for example, reagents, or
other materials rather than attempting to move such materials from
the device to the cartridge as part of the testing process.
[0014] While a cartridge can take a variety of different physical
forms, the development of precision electronics manufacturing
techniques and the associated field of microelectromechanical
systems (MEMS) has provided tools to support relatively low cost,
high volume, precision micro-manufacturing. Accordingly, many
cartridges include MEMS as the `guts` of the cartridge. The
cartridge may include additional components, including reservoirs,
batteries, and electronic components that are more difficult or
uneconomical to form using MEMS fabrication techniques. The MEMS
may be built up on a substrate and while silicon wafers and similar
semiconductor substrates are available, a wide variety of
substrates may be used.
[0015] Accordingly, the present specification describes, among
other examples, a microfluidics system. The system comprising: a
plurality of pumps and a plurality of sensors; a first
communication line to select a pump from the plurality of pumps and
select a sensor from the plurality of sensors; a second
communication line selectively connected to the selected pump; and
a third communication line selectively connected to the selected
sensor.
[0016] The present specification also describes a method of making
microfluidics measurements. The method comprising: using a single
communication line, selecting a sensor from a plurality of sensors
and a pump from a plurality of pumps; activating the selected pump;
and obtaining a sensor measurement from the selected sensor during
the activation of the selected pump.
[0017] The present specification also describes a microfluidic
measurement system. The microfluidics measurement system
comprising: a substrate; a plurality of transistors mounted on the
substrate; a plurality of pumps mounted on the substrate, each pump
having an associated transistor, wherein a state of an associated
transistor controls whether a corresponding pump is selected; a
plurality of sensors mounted on the substrate, each sensor having
an associated transistor, wherein a state of an associated
transistor determines whether a corresponding sensor is selected; a
series of flip-flops, where each transistor of the plurality of
transistors has an associated flip-flip that controls a state of
the corresponding transistor; a data line providing a state to a
first flip-flop in the series of flip-flops; a pump activation line
selectively connected electrically to a selected pump; a sensor
line selectively connected electrically to the selected sensor; and
a signal line to provide a signal to the series of flip-flops, upon
receipt of the signal on the signal line, a state of a flip-flop in
the series of flip-flops is transmitted to a next flip-flop in the
series of flip-flops.
[0018] Turning now to the figures:
[0019] FIG. 1 shows a system consistent with this specification.
The system (100) includes a substrate (110) with a plurality of
pumps (170) and a plurality of sensors (160). While any number of
pumps (170) and sensor (160) can be produced on the substrate
(110), a finite number are shown in the figures for clarity. The
system (100) includes a number of communication lines that allow
the components on the substrate to send and receive signals from an
external source. The communication lines connect to pads (120, 130,
140, 150) which provide the contacts to external components. Each
pump (170) and each sensor (160) has a transistor (180) associated
with it. When the transistor (180) is in a first state, the
associated pump (170) and/or sensor (160) is connected with an
external communication pad (120, 130). When the transistor is in a
second state, the associated pump (170) and/or sensor (160) is not
connected with an external communication pad (120, 130). The
transistors (180) are controlled by a series of flip-flops (190) so
that each time a signal is provided to the system by a signal pad
(150), the values in the transistors (180) are propagated to the
next transistor (180) in the chain. Accordingly, the whole of a
chain of X transistor can be set to the proper states by providing
the proper sequence of states on a data pad (140) and advancing the
states down the chain of flip-flops (190) and associated
transistors (180) by applying a series of signals on the signal pad
(150).
[0020] The line associated with the first external communication
pad (120) is the pump activation line (122). The line associated
with the second external communication pad (130) is the sensor line
(132). The line associated with the data pad (140) is the data line
(142). The line associated with the signal pad (150) is the signal
line (152).
[0021] One advantage of this approach is it limits the number of
pads needed to manage any number of pumps (170) and/or sensors
(160). This reduces the cost of fabricating the system (100), which
in turn reduces the per test cost.
[0022] One examples uses a single external communication pad (120,
130) and associated line to both provide the firing impulses to the
pumps (170) and obtain measurements from the sensors (160).
However, this design has some challenges. Specifically, for some
types of testing, the firing pulses applied through created
significant noise on the shared communication line and associated
external communication pad (120, 130). Further, sensor measurements
are not available while using the shared communication line to
activate the pump. Also, in this example there is a time lag during
shifting the communication line from a pump (170) to a sensor (160)
during which measurements are not obtained. Similarly, when a
sequence of pumping and measurements were needed, the system had
gaps in the measurement windows when pumping and shifting between
measurement and pumping.
[0023] In contrast, the present system, with its independent
communication pads for the pumps (130) and the sensors (120) allows
a sensor to measure while a pump is active. This separation also
isolates the two signals, preventing inadvertent application of
relatively large pump voltages to the sensors. This approach
reduces cross talk between the pump firing signals and the sensor
output, which improves the signal to noise ratio (S/N ratio) for
the sensor measurements. Improved S/N ratio can allow the use of
less expensive components to obtain similar measurements and/or can
be used to improve the quality of the measurements depending on the
specific design goals for the device.
[0024] The system (100) is a system for preforming microfluidics
measurements. It includes a variety of components mounted on a
substrate (110). The system (100) may be designed to interact with
a separate device. In some examples, the system is a cartridge
(100). In some examples, the system is disposable. In other
examples, the system is reusable and/or refurbishable.
[0025] The substrate (110) supports the components of the system
(100). In some examples, the substrate (110) comprises silicon. The
substrate (110) may include internal conductive traces and/or
components. Other conductive traces and/or components may be
mounted on one or both surfaces. The substrate includes a number of
pads (120, 130, 140, 150) for facilitating communications off the
substrate (110). The pads (120, 130, 140, 150) may make electrical
connection with external conductors. The pads (120, 130, 140, 150)
may communicate wirelessly, optically, by radio, electromagnetic
wave, and/or similar technologies. In one example, the substrate
(110) includes a power source such as a battery that converts the
signals received at the pads into electrical signals. In other
examples, power is provided by an external device by a direct
connection and/or inductive transfer.
[0026] The first external communication pad (120) provides firing
pulses to the pumps (170) on the substrate (110). The firing pulses
travel from the first external communication pad (120) to the pumps
(170) that have a selected associated transistor (180). The firing
pulses are prevented from traveling to the pumps (170) that do not
have a selected associated transistor (180). In one example, a
single pump (170) is selected at a time. In other examples,
multiple pumps (170) may be selected and fired at the same time. A
pump (170) may be activated while a measurement is being acquired
from a sensor (160). Alternately, a pump (170) may perform fluid
handling before and/or after sensor (160) measurements. The pumps
(170) may be any suitable pump (170) sized to operate with the
substrate (110). The pumps (170) may be a piezoelectric membrane
pumps (170). The pumps (170) may be bubble pumps (170) which
operate by vaporizing a portion of a fluid to produce an expanding
bubble. The pumps (170) may include associated valves, including
one-way valves. The pumps (170) need not be the same type or
design, although there are manufacturing advantages to
standardizing them. The pumps (170) may be augmented with
evaporative and/or capillary actions to facilitate fluid management
on the substrate (110).
[0027] The second external communication pad (130) is used to
provide sensor measurements to an external location. This external
location may be a device. The external location may be the source
of the firing pulses. The external communication pad is connected
to a single sensor (160) using a selected transistor (180).
Incrementing or loading new bits into the flip-flops (190) allows
the selected transistor (180) to be changed to a different
transistor (180) associated with a different sensor (160). The
second communication pad (130) is not connected with multiple
sensors (160) simultaneously. If measurements are desired to be
made on two different sensors (160) simultaneously, a third
external communication pad (not show) can be incorporated into the
system (110) and some of the sensors (160) are made to communicate
through the second external communication pad (130) and some
sensors are made to communicate through the third external
communication pad. This approach can be repeated to add even more
sensors available for simultaneous measurement. However, there are
diminishing returns as each sensor (160) that can be simultaneously
measured adds an additional external communication pad (120, 130)
with the associated monetary and equipment cost.
[0028] The data pad (140) provides the bits that are loaded into
the flip-flops (190). Those bits determine the states of the
transistors (180). The transistors (180), in turn, control which
sensor (160) and pump(s) (170) are available on the external
communication pads (120, 130).
[0029] The signal pad (150) provides signals to the flip-flops
(190) to advance the stored bit to the next flip-flop (190) in the
chain. These stored bits, in turn, control the state of the
transistors (180) which in turn control which sensor (160) and
pump(s) (170) are available on the external communication pads
(120, 130). The signal can be any suitable signal. In one example,
the signal is a clock signal. In one example, the signal is a level
signal. In another example, the signal is an edge signal.
[0030] The sensors (160) can include any of a variety of sensors
that may be used to make measurements in a microfluidics
environment. The sensors (160) may be all of the same type.
Alternately, the sensors (160) may include a variety of different
sensors types. The sensors (160) are likely located at different
positions on the substrate (110). The material being evaluated by
the sensors (160) may be subjected to a variety of preloading or on
substrate processing prior to taking the sensor (160) measurement.
Detailed description of the particular sensor (160) types and their
method of operation is not the purpose of this specification.
However, a non-limiting list of examples of sensors and
measurements includes: impedance sensors, absorbance sensors,
optical sensors, proximity sensors, composition sensors, ultrasound
sensors, capacitive sensors, and resonance sensors. As discussed
above, a single sensor is electrically available at the second
external communication pad (130) at a given time. To make a
multiple sensors available simultaneously, an additional external
communication pad can be added and indexed with the flip-flops
(190) and transistors (180).
[0031] The pumps (170) facilitate fluid management. The pumps (170)
may be any suitable pump (170) that can operate with the substrate
(110). The pumps (170) may be piezoelectric membrane pumps (170).
The pumps (170) may be bubble pumps (170) which operate by
vaporizing a portion of a fluid to produce an expanding bubble. The
pumps (170) may include associated valves, including one-way
valves. The pumps (170) need not be the same type or design,
although there are manufacturing advantages to standardizing them.
The pumps (170) may be augmented with evaporative and/or capillary
actions to facilitate fluid management on the substrate (110). A
pump (170) is associated with the first external communication pad
(120) using the transistors (180) and the flip-flops (190). In some
examples, multiple pumps (120) may be associated with the first
external communication pad (120) at the same time.
[0032] The transistors (180) perform the selection of the
addressable sensor (160) and pump (170). The transistor (180) state
is controlled by an associated flip-flop (190). Bits are loaded
into the flip-flops (190) using the data pad (140) and the signal
pad (150). Those bits are propagated down the chain of flip-flops
(190). This approach allows the selection from a large number of
sensors using two pads (140, 150). Accordingly, the system can
include a larger number of different sensor geometries, pump types,
configurations, etc. without increasing the number of pads and the
associated costs. This provides greater flexibility in design and
allows a given system (100) design to provide a larger number of
tests. Using a single design to support more tests, in turn,
reduces the number of systems (100) that need to be available. It
also facilitates economies of scale in both manufacturing and
supply management.
[0033] The flip-flops (190) allow the bits that control the
transistors (180) to be provided to the system (100) via serial
action using the data pad (140) and signal pad (150). The
flip-flops (190) are chained together so that with each appropriate
signal on the signal pad (150), the bits advance to the next
flip-flop (190). This in turn allows the state of the transistors
(180) to be controlled, which in turn provides selection of the
pump (170) and/or sensor (160) in communication with the external
communication pads (120, 130). The use of the serial communication
allows the data pad (140) and signal pad (150) to select from any
number of pumps (170) and/or sensors (160). In contrast, using
parallel communication uses log 2 (n) pads.
[0034] The term flip-flops (190) as used in this specification and
the associated claims includes both edge sensitive and level
sensitive devices. Accordingly, it also includes latches including
simple latches and similar devices that are capable of maintaining
two distinct states and propagating those states down the series of
devices in response to an input. While the input may be provided as
a clock signal, any suitable triggering input will provide the same
functionality. Alternately, the input may be a level, transition,
edge, etc.
[0035] FIG. 1 shows the use of single data line to load the
flip-flops (190). However, other configurations are possible. For
example, if the loading or switching time is unacceptably long,
additional data pads can be provided and the flip-flops (190)
divided into banks. In one example, the transistors (180) that
control selection of the pumps (170) are in a first bank and the
transistors (180) that control selection of the sensors (160) are
in a second bank. In another example, each bank includes
transistors that control both pumps (170) and/or sensors (160).
Clearly, additional banks of flip-flops (190) can be added to
optimize the tradeoff between cartridge cost and loading speed.
[0036] FIG. 1 also shows that the state of the first transistor
(180) is controlled by the state on the data pad (140). As another
variation, the first transistor (180) can be controlled by a second
flip-flop (190) as so forth down the chain. These two different
approaches provide an engineering tradeoff. As shown in FIG. 1, the
system uses one fewer clock cycle to load the chain of flip-flops
(190) and the corresponding transistors (180). However, this
implies maintaining the state of the data pad (150) during
operation. In contrast, adding an additional flip-flop (190)
lengthens the load time by a clock cycle but makes the system
independent of the data pad (150) state during operation. Either
approach can be taken with the examples in this specification.
Which approach is preferable will depend on the relative design
value of data pad (150) state independence vs. loading time.
[0037] FIG. 2 shows a system consistent with this specification.
The system (100) comprises a substrate (110) with a plurality of
sensors (160) and pumps (170). The substrate also has pad (120,
130, 140, 150) to facilitate communication with other devices. The
first external communication pad (120) allows control signals to be
provided to a pump (170). The second external communication pad
(130) allows measurements to be obtained from a sensor (160). The
data pad (140) and signal pad (150) are used to provide a serial
series of bits to a series of flip-flops (190). The flip-flops
(190) in turn control the transistors (180) which in turn determine
which pump (170) and/or sensor (160) can be accessed using the
external communication pads (120, 130).
[0038] FIG. 2 differs from FIG. 1 in that instead of providing
independent flip-flops (190) and transistors (180) for each pump
(170) and each sensor (160), a flip-flop (190) is associated with
both a pump (170) and a sensor (160). In some versions, independent
transistors are still provided for each pump (170) and sensor
(160). In others, the transistors (180) are similarly combined for
the paired sensor (160) and pump (170). Examples of both
configurations are shown in FIG. 2. FIG. 2 shows all the pumps and
sensors in paired configuration. However, other configurations are
possible. For example, sensors that are used with just a particular
pump may be arranged in this paired arrangement while other pumps
and sensors may be arranged as shown in FIG. 1.
[0039] The approach shown in FIG. 2 has the advantage of reducing
the propagation time for the flip-flops (190) and switching time
between pumps (170) and sensors (160). In some examples, it may
allow for more pumps (170) or sensors (160) to fit on a given
substrate. It is also possible that a more general design such as
shown in FIG. 1 can be converted to FIG. 2 after fabrication. One
way this is performed is to arrange for some of the electrical
connections to be severed. This can be done mechanically. This can
also be done by including resistive elements as preset points and
then melting the connections at the resistive elements by applying
a high frequency current. When the conductor melts, surface tension
causes the melted material to form a droplet, severing the
conductive path. The material then cools and solidifies. Other
methods exist to modify MEMS and electronic components post
production, including laser, chemical, and thermal modifications.
Post-production modification can reduce manufacturing and in some
cases inventory costs using economies of scale. In one example, the
system is provided in the general configuration and is modified at
the point of use.
[0040] Although the pumps (170) are shown in a one to one
configuration with the sensors (160), other configurations are
possible within the scope of this specification. For example,
multiple pumps (170) may be associated with a single sensor (160).
Alternately, a pump (170) may be used with two different sensors
(160). In one example, the pump (170) receives a first activation
signal when a first sensor (160) is selected and the pump (170)
receives a second activation signal when a second sensor (160) is
selected. In some examples, the pump (170) receives multiple kinds
of activation signals when a first sensor (160) is selected.
[0041] FIG. 3 shows a system consistent with this specification.
The system (100) comprises a substrate (110) with a plurality of
sensors (160) and pumps (170). The substrate also has pad (120,
130, 140, 150) to facilitate communication with other devices. The
first external communication pad (120) allows control signals to be
provided to a pump (170). The second external communication pad
(130) allows measurements to be obtained from a sensor (160). The
data pad (140) and signal pad (150) are used to provide a serial
series of bits to a series of flip-flops (190). The flip-flops
(190) control the transistors (180) which in turn determine which
pump (170) and/or sensor (160) can be accessed using the external
communication pads (120, 130).
[0042] FIG. 3 differs from FIGS. 1 and 2 in that FIG. 3 includes
flip-flops (190) in the chain of flip-flops (190) that are not
connected to any transistor (180) and therefore do not allow
selection of any pump (170) or sensor (160). These unconnected
flip-flops (190) increase the overall propagation time for series
of flip-flops (190). However, careful placement of these
unconnected flip-flops (190) can reduce the switching time between
a first configuration and a second configuration. The unconnected
flip-flops (190) serve as storage locations for bits in the series
of flip-flop (190). With proper placement, they can enable
switching between two pumps and/or sensors that are separated by
intervening pumps (170) and/or sensors (160) with a single signal
to the signal pad (150). The signal results in the bits associated
with the selected pump (170) and/or sensor (160) being advanced to
an unconnected flip-flop (190) removing the previously selected
pump (170) and/or sensor (160) from electrical connection with the
external communication pads (120, 130). Further down the series of
flip-flops (190), other bits are moved from an unconnected
flip-flop (190) to a flip-flop (190) connected to a transistor
(180). This allows signals to pass to and be obtained from the pump
and/or sensor associated with the transistor (180).
[0043] FIG. 4 shows a method consistent with this specification.
The method (400) using a single communication line, selecting a
sensor from a plurality of sensors (160) and a pump from a
plurality of pumps (170) (410); activating the selected pump (170)
(420); and obtaining a sensor measurement from the selected sensor
(160) during the activation of the selected pump (170) (430).
[0044] Operation (410) comprises using a single communication line,
selecting a sensor from a plurality of sensors and a pump from a
plurality of pumps. Using a single line reduces the cost of the
test component by reducing the number of pads required. It also
facilities using a variety of different test systems (100) with a
given device because the device can use the two pads to control any
number of pumps (170) and/or sensors (160). In contrast, if
parallel loading were used, the number of potential selectable
devices in the system depends on the number of pads/channels
allocated for selection. Selection can be accomplished by serially
providing selection bits that control the connection between the
pumps and a pump line and the sensors and a sensor line.
[0045] Operation (420) comprises activating the selected pump. The
selection transistors (180) allow the pump activation signal to
activate just the selected pump (170) or pumps (170). This allows a
single pump activation signal generator to provide all the pump
activation signals to all the pumps (170) in the system (100) by
changing which pump (170) is currently selected. This reduces the
hardware needed in an associated device to interface with the
system (100) since it can use a single generator rather than
multiple generators.
[0046] Operation (430) comprises obtaining a sensor measurement
from the selected sensor during the activation of the selected
pump. This allows a single set of signal receiving and/or analysis
hardware to be used with all the sensors (160) in the system (100).
This can reduce the costs of a device used with the system (100)
since a single piece of measurement equipment can be used for all
sensors (160) of a given type in the system (100). This may also
reduce the time to perform calibration on the device as the one
piece of measurement equipment is used for multiple sensors (160).
If the device uses an analog to digital converter, it similarly can
be used with all of the sensors (160) again reducing the potential
component costs for an associated device.
[0047] Because the pump signal and sensor measurements are provided
on different external communication pads (120, 130), operations 420
and 430 can be performed simultaneously. The use of separate
external communication pads (120, 130) also reduces the noise from
the pump activation signal on the sensor measurements. The use of
different lines for the pump activation
[0048] FIG. 5 shows a system consistent with this specification.
The system (100) is a microfluidics system (100) on a substrate
(110) with a plurality of pumps (170) and a plurality of sensors
(160). The system includes a first communication line (142) for
selecting a pump from the plurality of pumps (170) and selecting a
sensor from the plurality of sensors (160); a second communication
line (122) for providing an activation signal to the selected pump;
and a third communication line (132) for obtaining an output from
the selected sensor.
[0049] The first communication line is a data line (142) for
selecting a pump from the plurality of pumps (170) and selecting a
sensor from the plurality of sensors (160). The second
communication line is a pump activation line (122) for activating
the selected pump and not activating the non-selected pumps. The
third communication line is a sensor line (132) to provide a sensor
measurement from the selected sensor.
[0050] Within the principles described by this specification, a
vast number of variations exist and that the examples are intended
to be merely representative, without limiting the scope,
applicability, or construction of the claims.
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