OPTICAL DISPLACEMENT SENSOR FOR INFUSION DEVICES

• US 20090224145A1
• Filed: 03/02/2009
• Published: 09/10/2009
• Est. Priority Date: 07/24/2002
• Status: Active Grant

• Current Assignee: Eugly Diabetes Care LLC
• Original Assignee: Deka Products Limited Partnership
• Inventors: GRAY, LARRY B., MANDRO, MARC A.
• Granted Patent: US 8,552,361 B2
• Time in Patent Office: Days
• US Class Current: 250/231.130
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/3379 Masses, volumes, levels of fluids in reservoirs, flow rates
• CPC Class Codes: A61M 2205/6063 Optical identification systems
• CPC Class Codes: A61M 5/145 using pressurised reservoirs, e.g. pressurised by means of pistons
• CPC Class Codes: A61M 5/1456 with a replaceable reservoir comprising a piston rod to be moved into the reservoir, e.g. the piston rod is part of the removable reservoir
• CPC Class Codes: A61M 5/16886 for measuring fluid flow rate, i.e. flowmeters
• CPC Class Codes: A61M 5/31525 Dosing burettes, pipettes B01L3/02
• CPC Class Codes: G01D 5/34746 Linear encoders
• CPC Class Codes: G01D 5/34776 Absolute encoders with analogue or digital scales

Abstract

An optical sensor for a delivery device having a piston that displaces a substance, such as a fluid, from a reservoir. The optical sensor has a light source and a detector array for imaging encoding features disposed along a plunger rod coupled to the piston. By virtue of the pattern of encoding features, an absolute position of the plunger rod relative to a fiducial position may be determined uniquely. Thus, the volume of fluid remaining in the reservoir, the rate of fluid delivery, and proper loading of the reservoir may be accurately ascertained. Additionally, the encoding may serve to uniquely identify a version of the reservoir which may be supplied in various versions corresponding, for example, to differing concentrations of a therapeutic agent to be dispensed.

Claims

1. A medical fluid dispensing apparatus comprising:

a reservoir having an inner volume for containing a medical fluid;

a piston having a linear motion, the piston driven at a prescribed rate by a motor, wherein the piston causes the medical fluid to be impelled out of the reservoir at a determined delivery rate; and

a displacement sensor for determining the volume of fluid remaining in the reservoir.

2. The apparatus of claim 1 further comprising a plunger rod coupled to the piston, the plunger rod bearing an encoded pattern of at least one encoding feature, wherein the encoding features include at least one optically transmissive feature.

3. The apparatus of claim 2 further comprising an illumination source, the illumination source located wherein light from the illumination source is transmitted to the at least one optically transmissive feature.

4. The apparatus of claim 2 further comprising at least one detector for detecting light transmitted to the at least one encoding feature.

5. The apparatus of claim 4 wherein the at least one encoding feature is a slot scored into the plunger rod.

6. The apparatus of claim 4 wherein the at least one encoding feature is an aperture.

7. The apparatus of claim 1 further comprising a plunger rod coupled to the piston, the plunger rod bearing an encoded pattern of encoding features, wherein the encoding features comprising a plurality of optically transmissive features.

8. The apparatus of claim 7 wherein the spacing of the encoding features from one another defines spaces between such that any two adjacent spaces form a unique sequence.