Drop ejection based flow sensor calibration

Patent metadata

Field	Value
Publication number	US-10495507-B2
Application number	US-201515546780-A
Country	US
Kind code	B2
Filing date	Apr 30, 2015
Priority date	Apr 30, 2015
Publication date	Dec 3, 2019
Grant date	Dec 3, 2019

Abstract

A droplet of fluid having a predetermined drop weight is ejected from a microfluidic channel. Electrical signals are received from a sensor in the microfluidic channel, wherein the electrical signals vary in response to the ejection of the droplet of fluid. The electrical signals of the sensor are calibrated to a rate of flow of fluid through the microfluidic channel based on a number of droplets ejected and the predetermined drop weight of each droplet.

First claim

What is claimed is:

1. An apparatus comprising:
a microfluidic channel;
a sensor along the microfluidic channel to output electrical signals that vary in response to fluid flow through the microfluidic channel;
a drop ejector having a predetermined drop weight along the microfluidic channel; and
calibration electronics to calibrate the electrical signals from the sensor to flow rate based upon drop ejection by the drop ejector.

2. The apparatus of claim 1 , wherein the drop ejector comprises a thermal inkjet resistor and a corresponding nozzle.

3. The apparatus of claim 1 , wherein the microfluidic channel comprises a primary channel and a branch channel stemming from the primary channel, wherein the sensor is in the primary channel and wherein the drop ejector is in the branch channel.

4. The apparatus of claim 3 further comprising a second sensor in the branch channel, the second sensor being identical to the sensor.

5. The apparatus of claim 4 further comprising a substrate supporting the microfluidic channel, the sensor and the drop ejector, where the apparatus further comprises a fluid interaction component supported by the substrate to interact with fluid directed through the primary channel.

6. The apparatus of claim 5 , wherein the fluid interaction component is selected from a group of fluid interaction components consisting of: a second microfluidic branch channel stemming from the primary channel; a microfluidic pump; a microfluidic multi-mixer; a second drop ejector; a microheater, an impedance sensor and a cytometer.

7. The apparatus of claim 3 further comprising a fluidic valve to selectively open and close the primary channel to direct fluid towards the branch channel.

8. The apparatus of claim 7 further comprising a second fluidic valve to selectively open and close the branch channel with respect to the primary channel.

9. The apparatus of claim 1 , wherein the sensor comprises:
a heat emitting resistor having a resistance that varies in response to temperature; and
a sensor to sense an electrical parameter of the heat emitting resistor that is based on the resistance of the heat emitting resistor.

10. The apparatus of claim 1 , wherein the sensor comprises a thermal mass flow sensor comprising a heating element and a temperature sensor spaced from the heating element, the temperature sensor outputting electrical signals that vary in response to fluid flow through the microfluidic channel.

11. The apparatus of claim 1 comprising a single substrate supporting the microfluidic channel, the sensor and the drop ejector.

12. The apparatus of claim 1 , wherein the microfluidic channel has a channel width of between 5 and 200 μm and a channel height of between 10 and 200 μm.

13. A method comprising:
ejecting a droplet of fluid having a predetermined drop weight from a microfluidic channel;
receiving electrical signals from a sensor in the microfluidic channel, the electrical signals varying in response to the ejection of the droplet of fluid; and
calibrating electrical signals from the sensor to corresponding fluid flow rate through the microfluidic channel based upon a number of droplets ejected and the predetermined drop weight of each droplet.

14. The method of claim 13 , wherein a substrate supports the microfluidic channel and a drop ejector used to carry out the ejection of the droplet of fluid and wherein the method further comprises directing fluid through the microfluidic channel to a fluid interaction component supported by the substrate.

15. An apparatus comprising a non-transitory computer-readable medium containing instructions to direct a processor to:
output signals to a drop ejector to eject a droplet of fluid from a microfluidic channel, the droplet having a predetermined drop weight;
receive electrical signals from a sensor along the microfluidic channel, the signals varying in response to ejection of the droplet; and
calibrate the sensor based upon a determined relationship between the received electrical signals from the sensor and a volume of fluid ejected by the drop ejector.

16. The apparatus of claim 1 , wherein the calibration electronics correlate different electrical signals from the sensor to different flow rates through the microfluidic channel.

17. The apparatus of claim 1 comprising a single substrate supporting the microfluidic channel, the sensor, the drop ejector and the calibration electronics.

18. The apparatus of claim 17 further comprising a fluid interaction component selected from a group of fluid interaction components consisting of: a microfluidic pump, a microfluidic multi-mixer, an impedance sensor and cytometer.

19. The apparatus of claim 1 further comprising a fluid interaction component selected from a group of fluid interaction components consisting of: a microfluidic pump, a microfluidic multi-mixer, an impedance sensor and cytometer.

20. The apparatus of claim 1 , wherein the calibration electronics correlate different electrical signals from the sensor two different flow rates based upon the predetermined drop weight of the drop ejector and drop ejection by the drop ejector.

Assignees

• Hewlett Packard Development Co

Inventors

• Govyadinov Alexander
• Torniainen Erik D
• Kornilovich Pavel
• Markel David P

Classifications

• B41J2/11

  for ink spray · CPC title

• B41J2/08 Primary

  charge-control type · CPC title

• B41J2/0456

  detecting drop size, volume or weight · CPC title

• G01F25/00

  Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume · CPC title

• B41J2/14153

  Structures including a sensor · CPC title