APPARATUS FOR SUBSTANCE DETECTION

• US 20140117254A1
• Filed: 10/31/2012
• Published: 05/01/2014
• Est. Priority Date: 11/07/2011
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Cobb, Joshua Monroe
• Granted Patent: US 9,375,172 B2
• Time in Patent Office: Days
• US Class Current: 250/459.1
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14556 by fluorescence A61B5/14555 takes precedence
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/021 using plane or convex mirrors, parallel phase plates, or particular reflectors
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/4406 Fluorescence spectrometry
• CPC Class Codes: G01N 2021/6421 Measuring at two or more wavelengths
• CPC Class Codes: G01N 2021/6471 Special filters, filter wheel
• CPC Class Codes: G01N 21/645 Specially adapted constructive features of fluorimeters
• CPC Class Codes: G01N 2201/0639 Sphere lens

Abstract

A sensing apparatus for detecting light of first and second fluorescent wavelength bands has a light source to generate an excitation wavelength to a first collimator element. A dichroic multiplexer has a first coated surface oblique to the optical axis and treated to transmit the excitation wavelength and to reflect the second fluorescent wavelength band and a second coated surface treated to transmit the excitation wavelength and the second fluorescent wavelength band and to reflect the first fluorescent wavelength band. A focusing element focuses the excitation light toward a light guide and directs collimated light of the first and second fluorescent wavelength bands from the light guide to the dichroic multiplexer. A first detector element is in the path of reflected light of the first fluorescent wavelength band and a second detector element is in the path of reflected light of the second fluorescent wavelength band.

Claims

1. A sensing apparatus for detecting light of a first fluorescent wavelength band and light of a second fluorescent wavelength band from a sample, the apparatus comprising:

a light source energizable to generate a light of an excitation wavelength and disposed along an optical axis in a first focal region of a first collimator element;

a dichroic multiplexer formed on a transparent substrate and comprising;

(i) a first coated surface oblique to the optical axis and treated to transmit light of the excitation wavelength and to reflect light of at least the second fluorescent wavelength band;

(ii) a second coated surface spaced apart from the first coated surface and treated to transmit light of the excitation wavelength and of the second fluorescent wavelength band and to reflect light of the first fluorescent wavelength band;

a focusing element disposed to focus the light of the excitation wavelength toward a light guide and to direct collimated light of the first fluorescent wavelength band and collimated light of the second fluorescent wavelength band from the light guide to the dichroic multiplexer;

a first detector element in the path of reflected light of the first fluorescent wavelength band from the second coated surface; and

a second detector element in the path of reflected light of the second fluorescent wavelength band from the first coated surface.

2. The sensing apparatus of claim 1 wherein the first and second coated surfaces are parallel to each other.

3. The sensing apparatus of claim 1 wherein the first and second coated surfaces are obliquely disposed with respect to each other.

4. The sensing apparatus of claim 1 wherein the transparent substrate is fused silica.

5. The sensing apparatus of claim 1 wherein the light source is a solid-state light source.

6. The sensing apparatus of claim 1 wherein one or more of the focusing element or the first collimator element is a ball lens.

7. The sensing apparatus of claim 1 wherein the light guide comprises an optical fiber.

8. The sensing apparatus of claim 1 further comprising a baffle between the path of reflected light of the first fluorescent wavelength band and reflected light of the second fluorescent wavelength band.

9. The sensing apparatus of claim 1 wherein the first collimator element is taken from the group consisting of an aspheric lens, a ball lens, a gradient index lens, and a concave mirror.

10. The sensing apparatus of claim 1 further comprising a first focusing lens in the path of reflected light of the first fluorescent wavelength band.

11. The sensing apparatus of claim 10 wherein the first focusing lens comprises a reflective surface.

12. The sensing apparatus of claim 1 wherein one or more of the focusing element or the first collimator element further comprise a reflective surface for folding the optical axis.

13. A glucose level sensing apparatus comprising:

a light source energizable to generate a light of an excitation wavelength and disposed along an optical axis in a first focal region of a first collimator element;

a dichroic multiplexer formed on a transparent substrate and comprising;

(i) a first coated surface oblique to the optical axis and treated to transmit light of the excitation wavelength and to reflect light of at least the second fluorescent wavelength band;

(ii) a second coated surface parallel to the first coated surface and treated to transmit light of the excitation wavelength and of the second fluorescent wavelength band and to reflect light of the first fluorescent wavelength band;

a focusing element disposed to focus the light of the excitation wavelength toward a light guide to the sample, and to direct collimated light of the first fluorescent wavelength band and collimated light of the second fluorescent wavelength band from the light guide to the dichroic multiplexer;

a first detector element in the path of reflected light of the first fluorescent wavelength band from the second coated surface;

a second detector element in the path of reflected light of the second fluorescent wavelength band from the first coated surface; and

a control logic processor in signal communication with the light source and with the first and second detector elements and further in signal communication with a display device for displaying a result according to signals obtained from the first and second detector elements.

14. The sensing apparatus of claim 13 wherein the first and second coated surfaces are parallel to each other.

15. The sensing apparatus of claim 13 wherein the first and second coated surfaces are obliquely disposed with respect to each other.

16. The sensing apparatus of claim 13 wherein the transparent substrate is fused silica.

17. The sensing apparatus of claim 13 wherein the light source is a solid-state light source.

18. The sensing apparatus of claim 13 wherein one or more of the focusing element or the first collimator is a ball lens.

19. The sensing apparatus of claim 13 wherein the light guide comprises an optical fiber.

20. A method for detecting light of a first fluorescent wavelength band and light of a second fluorescent wavelength band from a sample, the method comprising:

energizing a solid state light source and directing collimated light of an excitation wavelength along an optical axis toward a dichroic multiplexer that is formed on a transparent substrate and that comprises;

(i) a first coated surface oblique to the optical axis and treated to transmit light of the excitation wavelength and to reflect light of the second fluorescent wavelength band;

(ii) a second coated surface spaced apart from the first coated surface and treated to transmit light of the excitation wavelength and of the second fluorescent wavelength band and to reflect light of the first fluorescent wavelength band;

focusing the light of the excitation wavelength toward a light guide to the sample, and directing light of the first fluorescent wavelength band and light of the second fluorescent wavelength band from the light guide to the dichroic multiplexer;

obtaining a first signal from a first detector element in the path of light of the first fluorescent wavelength band reflected from the second coated surface of the dichroic multiplexer;

obtaining a second signal from a second detector element in the path of light of the second fluorescent wavelength band reflected from the first coated surface of the dichroic multiplexer; and

displaying a result according to the obtained first and second signals.