Multi-way LED-based chemochromic sensor

• US 7,008,795 B2
• Filed: 09/20/2002
• Issued: 03/07/2006
• Est. Priority Date: 09/20/2002
• Status: Expired due to Fees

• Current Assignee: Dublin City University, Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Yerazunis, William S., Dietz, Paul H., Diamond, Dermot
• Primary Examiner(s): Snay, Jeffrey R.
• Application Number:
  US10/251,251
• Publication Number:
  US 20040057873A1
• Time in Patent Office: 1,264 Days
• Field of Search: 436/167, 436/169, 436/170, 436/172, 422/82.05, 422/82.08, 422/82.09, 422/82.11, 422/86, 422/87, 422/91
• US Class Current: 436/164
• CPC Class Codes: G01N 21/78 producing a change of colour

Abstract

A chemochromic sensor includes multiple bi-directional LEDs, each optically aligned with one or more test areas. Each LED is used as both a light emitter when driven in forward bias, and as a light detector when driven in reverse bias. By alternating the bias on the LEDs, multi-way light measurements of the test area can be obtained.

Claims

1. A chemochromic sensor comprising:

a microprocessor including a first pair of I/O pins and a second pair of I/O pins, and means for measuring a voltage drop across the first pair of I/O pins and the second pairs of I/O pins;

a first light-emitting diode connected to the first pair of I/O pins;

a second light-emitting diode connected to the second pair of I/O pins;

a test area configured to receive a mixture of a chemochromic reagent and a test material; and

means for driving the first light-emitting diode in forward bias to emit light onto the test area while driving the second light-emitting diode in reverse bias to sense light from the test area by measuring the voltage drop across the second pair of I/O pins to measure a first amount of the test material.

2. The sensor of claim 1 further comprising:

means for driving the second light-emitting diode in forward bias to emit light onto the test area while driving the first light-emitting diode in reverse bias to sense light from the test area by measuring the voltage drop across the first pair of I/O pins to measure a second amount of the test material; and

means comparing the first and second amounts to differentially measure the test material.

3. The chemochromic sensor according to claim 1 wherein the test area is located on a light-guide optically coupling the first and second light-emitting diodes.

4. The chemochromic sensor according to claim 3 wherein the first and second light-emitting diodes are at right angles to each other and the light-guide is elbow-shaped.

5. The chemochromic sensor according to claim 3 wherein the test area is at a corner of the light-guide.

6. The chemochromic sensor according to claim 1 wherein the voltage drop is measured by a timer of the microprocessor.

7. A method for sensing a chemochromic reagent and test material comprising:

driving a first light-emitting diode, having a first pair of I/O pins, in forward bias to emit light onto a test area containing a mixture of the chemochromic reagent and the test material; and

driving a second light-emitting diode, having a second pair of I/O pins, in reverse bias to sense light from the test area by measuring a voltage drop across the second pair of I/O pins to measure a first amount of test material.

8. The method of claim 7 further comprising:

driving the second light-emitting diode in forward bias to emit light onto the test area containing a mixture of the chemochromic reagent and the test material; and

driving the first light-emitting diode in reverse bias to sense light from the test area by measuring the voltage drop across the first pair of I/O pins to differentially measure a second amount of the test material; and

comparing the first and second amounts to differentially measure the test material.

9. A chemochromic sensor comprising:

a microprocessor including a plurality of pairs of I/O pins and means for measuring a voltage drop across each pair of I/O pins;

a plurality of light-emitting diodes, one light emitting diode connected to one pair of I/O pins;

a plurality of test areas each configured to receive chemochromic materials; and

means for driving a particular light-emitting diode in forward bias to emit light onto selected test areas while driving other ones of the light-emitting diodes in reverse bias to sense light reflected from the selected test areas by measuring the voltage drop across corresponding pairs of I/O pins of the reverse driven light emitting diodes, the voltage drops corresponding to amounts of the chemochromic materials.