Detector with coated lens assembly

• US 20050184240A1
• Filed: 09/30/2004
• Published: 08/25/2005
• Est. Priority Date: 02/20/2004
• Status: Active Grant

• Current Assignee: Suppression Technologies Incorporated
• Original Assignee: Suppression Technologies Incorporated
• Inventors: Cranford, Ron D.
• Granted Patent: US 7,026,619 B2
• Time in Patent Office: Days
• US Class Current: 250/353
• CPC Class Codes: G01J 5/0022 for sensing the radiation of moving bodies
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: G01J 5/0205 Mechanical elements; Supports for optical elements
• CPC Class Codes: G01J 5/04 Casings
• CPC Class Codes: G01J 5/042 High-temperature environment G01J5/0007, G01J5/0044, G01J5/0088 and G01J5/004 take precedence
• CPC Class Codes: G01J 5/046 Materials; Selection of thermal materials
• CPC Class Codes: G01J 5/068 by controlling parameters other than temperature
• CPC Class Codes: G01J 5/08 Optical arrangements
• CPC Class Codes: G01J 5/0802 Optical filters
• CPC Class Codes: G01J 5/0806 Focusing or collimating elements, e.g. lenses or concave mirrors

Abstract

A spark detector lens assembly is adapted to block energy from static electric discharges. The lens assembly includes a housing which receives a lens. The lens is adapted to pass infrared frequency energy therethrough. A conductive coating is disposed on one side of said lens, which is effective to block radio frequency energy but pass infrared frequency energy. The conductive coating may be electrically connected to an electrical ground path. The lens assembly is especially effective for preventing false alarms by shielding a spark detector from radio frequency energy radiated by static electric discharges.

Claims

1. A spark detector lens assembly adapted to block energy from static electric discharges, said lens assembly comprising:

a housing for receiving a lens;

a lens disposed in said housing, said lens adapted to pass infrared frequency energy therethrough;

a conductive coating disposed on one side of said lens, said coating effective to block radio frequency energy but pass infrared frequency energy therethrough; and

means for electrically connecting said conductive coating to an electrical ground path.

2. The lens assembly of claim 1 wherein said housing is electrically conductive.

3. The lens assembly of claim 2 wherein said conductive coating is electrically connected to said housing.

4. The lens assembly of claim 2 wherein a conductive material is disposed in contact with said conductive coating and said housing.

5. The lens assembly of claim 4 wherein said conductive material is an epoxy.

6. The lens assembly of claim 1 wherein said conductive coating comprises indium-tin-oxide.

7. The lens assembly of claim 1 wherein the thickness of said coating is from about 1 micron to about 4 microns.

8. The lens assembly of claim 7 wherein the thickness of said coating is about 1 micron.

9. A spark detector comprising:

a spark sensor responsive to the impingement of radiation thereon;

a lens adapted and positioned to pass infrared energy therethrough to said spark sensor;

a conductive coating disposed on one side of said lens, said coating effective to block radio frequency energy but pass infrared energy therethrough; and

an electrical ground path connected to said coating.

10. The spark detector of claim 9 wherein said housing is electrically conductive.

11. The spark detector of claim 10 wherein said conductive coating is electrically connected to said housing.

12. The spark detector of claim 11 wherein a conductive epoxy is disposed in contact with said conductive coating and said housing.

13. The spark detector of claim 10 wherein said conductive coating comprises indium-tin-oxide.

14. The spark detector of claim 10 wherein the thickness of said coating is from about 1 micron to about 4 microns.

15. The spark detector of claim 14 wherein the thickness of said coating is about 1 micron.

16. The spark detector of claim 10 wherein said housing is mounted in a casing.

17. The spark detector of claim 16 wherein said casing is electrically conductive and said casing is connected to an electrical ground path.

18. The spark detector of claim 16 wherein said casing comprises high temperature plastic.