Defrosting mirror

• US 4,071,736 A
• Filed: 02/12/1976
• Issued: 01/31/1978
• Est. Priority Date: 02/12/1976
• Status: Expired due to Term

• Current Assignee: Donnelly Corporation (Magna International Incorporated)
• Original Assignee: Donnelly Mirrors Limited
• Inventors: Kamerling, Marc A.
• Primary Examiner(s): Albritton, C. L.
• Application Number:
  US05/657,610
• Time in Patent Office: 719 Days
• Field of Search: 219/219, 219/528, 219/549, 338/225
• US Class Current: 219/219
• CPC Class Codes: B60R 1/0602 comprising means for cleaning or deicing
• CPC Class Codes: H05B 3/146 Conductive polymers, e.g. polyethylene, thermoplastics
• CPC Class Codes: H05B 3/845 specially adapted for reflecting surfaces, e.g. bathroom - or rearview mirrors

Abstract

The specification discloses a defrosting mirror especially adapted for outdoor use such as on the exterior of vehicles. The mirror includes an electrically conductive, resistive coating applied to a surface of a light reflective mirror element. The coating includes micro-sized graphite particles dispersed throughout a resinous binder material such that electricity flows through the coating to generate heat which is transferred to the mirror element. A resinous primer layer intermediate the coating and mirror element bonds the coating to the mirror element for retention of the conductive, resistive coating especially when the mirror is exposed to humidity, salt spray, or other environmental or weather conditions.

Claims

1. A defrosing mirror especially adapted for outdoor use on the exterior of vehicles or the like comprising:

a mirror element having a light-reflective coating on one surface thereof;

an electrically conductive, resistive, coating applied over at least one surface of said mirror element to generate heat when electricity is conducted therethrough, said coating including a layer of binder material adhering to said mirror surface and a plurality of graphite particles dispersed in contact with one another throughout said binder material;

conducting means for conducting electricity to and from respectively opposing portions of said electrically conductive coating to form an electrical circuit through said coating, said opposing portions being spaced apart across said one surface of said mirror element over which said electrically conductive coating is applied; and

an adhesion promoting, primer layer intermediate said one surface of said mirror element and said electrically conductive, resistive coating and uniformly contacting said mirror element surface and electrically conductive coating and bonded to said surface and coating to facilitate retention of said coating on said mirror element especially when said mirror is exposed to moisture, humidity, salt spray or solutions, or other environmental or weather conditions;

said electrically conductive, resistive coating being applied directly to and over said adhesion promoting primer layer and uniformly contacting said primer layer to ensure proper retention of said coating to said mirror element, while the electrically conductive coating ensures substantially constant electrical resistance and uniform heating of said mirror element.

2. The defrosting mirror of claim 1 wherein said binder material is a resinous material.

3. The defrosting mirror of claim 2 wherein said resinous material is a fortified organic polymer.

4. The defrosting mirror of claim 3 wherein said fortified organic polymer is a fluoroelastomer polymer.

6. The defrosting mirror of claim 1 wherein said electrically conductive, resistive coating is applied to the rear surface of said mirror element;

said light-reflective coating being applied to the front surface of said mirror element.

7. The defrosting mirror of claim 1 wherein said light-reflective coating is applied directly to the rear surface of said mirror element;

said primer layer and electrically conductive, resistive coating being applied successively over a coating of insulating paint applied over said reflective coating on said rear surface.

8. The defrosting mirror of claim 1 further including a layer of insulating material applied over said electrically conductive coating to protect said coating and prevent electrical shorting of the electrical circuit.

9. The defrosting mirror of claim 8 wherein said insulating material is a layer including acrylic emulsion resin.

10. The defrosting mirror of claim 8 wherein said insulating material is a layer including polyurethane.

11. The defrosting mirror of claim 8 including a thermostat for regulating the flow of electricity through said conducting means and electrically conductive coating, said thermostat being adhered to said layer of insulating material.

12. The defrosting mirror of claim 1 wherein said conducting means includes a thermostat for regulating the flow of electricity and thus, a quantity of heat produced by said electrically conductive coating.

13. The defrosting mirror of claim 1 wherein said primer layer includes adhesion promoting plastic resin.

15. The defrosting mirror of claim 1 wherein said conducting means include a pair of spaced, elongated electrically conductive metallic strips adhered to said primer layer to which said electrically conductive coating is applied, said electrically conductive coating contacting each of said strips along the entire length of each of said strips.

16. The defrosting mirror of claim 15 wherein each of said strips has a predetermined thickness, said electrically conductive coating extending over at least one edge, and thus, overlapping the thickness of said metallic strips along their entire lengths.

5. A defrosting mirror especially adapted for outdoor use on the exterior of vehicles or the like comprising:

a mirror element having a light-reflective coating on one surface thereof;

an electrically conductive, resistive, coating applied to at least one surface of said mirror element to generate heat when electricity is conducted therethrough, said coating including a layer of binder material adhering to said mirror surface and a plurality of graphite particles dispersed in contact with one another throughout said binder material;

conducting means for conducting electricity to and from respectively opposing portions of said electrically conductive coating to form an electrical circuit through said coating, said opposing portions being spaced apart across said one surface of said mirror element to which said electrically conductive coating is applied; and

an adhesion promoting, primer layer intermediate said one surface of said mirror element and said electrically conductive, resistive coating to facilitate retention of said coating on said mirror element especially when said mirror is exposed to moisture, humidity, salt spray or solutions, or other environmental or weather conditions;

said binder material being a resinous material including a fluoroelastomer polymer;

said graphite particles being micro-sized, coinlike particles dispersed such that they overlap and contact one another to form the electrical circuit.

14. A defrosting mirror especially adapted for outdoor use on the exterior of vehicles or the like comprising:

a mirror element having a light-reflective coating on one surface thereof;

an electrically conductive, resistive, coating applied to at least one surface of said mirror element to generate heat when electricity is conducted therethrough, said coating including a layer of binder material adhering to said mirror surface and a plurality of graphite particles dispersed in contact with one another throughout said binder material;

conducting means for conducting electricity to and from respectively opposing portions of said electrically conductive coating to form an electrical circuit through said coating, said opposing portions being spaced apart across said one surface of said mirror element to which said electrically conductive coating is applied; and

an adhesion promoting, primer layer intermediate said one surface of said mirror element and said electrically conductive, resistive coating to facilitate retention of said coating on said mirror element especially when said mirror is exposed to moisture, humidity, salt spray or solutions, or other environmental or weather conditions;

said primer layer including an adhesion promoting plastic resin having acrylic and phenolic resins and amino silane.

17. A defrosting mirror especially adapted for exterior use on vehicles or in other weather and environment exposed conditions comprising:

a mirror element having front and back surfaces and a light-reflective coating on at least one of said surfaces;

a primer layer applied directly on said back surface of said mirror element;

a pair of electrically conductive strips spaced apart from one another adjacent opposite edges of said mirror element and secured to the back of said mirror element;

an electrically conductive, resistive coating applied to the back surface of said mirror element and directly on and over said primer layer to generate heat when electricity is conducted therethrough, said coating electrically contacting each of said electrically conductive strips and extending across and covering the area of said back of said mirror element intermediate said spaced electrically conductive strips, said coating including a layer of binder material adhering to said primer layer and a plurality of graphite particles dispersed within said binder material and sufficiently in contact with one another to conduct electricity through said coating between said conductive strips;

means for conducting electricity to said electrically conductive strips, and thus, to said electrically conductive, resistive coating;

said primer layer being intermediate said mirror element back surface and said electrically conductive, resistive coating for facilitating adherence of said electrically conductive, resistive coating to said mirror element especially when said mirror is exposed to moisture, humidity, salt spray or solutions, or other environmental or weather conditions, said primer layer uniformly contacting and adhering to said mirror element back surface and said electrically conductive, resistive coating and bonded to said surface and coating;

said electrically conductive, resistive coating uniformly contacting said primer layer to ensure proper retention of said coating to said mirror element while said electrically conductive coating ensures substantially constant resistance and uniform heating of said mirror element.

18. The defrosting mirror of claim 17 wherein said binder material is a resinous material.

19. The defrosting mirror of claim 18 wherein said resinous material is a fluoroelastomer polymer.

20. The defrosting mirror of claim 19 further including a layer of insulating material applied over said electrically conductive coating to protect said coating and prevent electrical shorting of the electrical circuit.

22. The defrosting mirror of claim 20 wherein said conducting means includes a thermostat for regulating the flow of electricity, and thus, the quantity of heat produced by said electrically conductive coating.

23. The defrosting mirror of claim 22 wherein said electrically conductive strips include elongated strips of metallic tape adhered to said primer layer;

said conducting means being soldered to said metallic strips.

21. A defrosting mirror especially adapted for exterior use on vehicles or in other weather and environment exposed conditions comprising:

a mirror element having front and back surfaces and a light-reflective coating on at least one of said surfaces;

a pair of electrically conductive strips spaced apart from one another adjacent opposite edges of said mirror element and secured to the back of said mirror element;

an electrically conductive, resistive coating applied to the back surface of said mirror element to generate heat when electricity is conducted therethrough, said coating electrically contacting each of said electrically conductive strips and extending across and covering the area of said back surface intermediate said spaced electrically conductive strips, said coating including a layer of binder material adhering to said mirror back surface and a plurality of graphite particles dispersed within said binder material and sufficiently in contact with one another to conduct electricity through said coating between said conductive strips;

means for conducting electricity to said electrically conductive strips, and thus, to said electrically conductive, resistive coating; and

a primer layer intermediate said mirror element back surface and said electrically conductive, resistive coating for facilitating adherence of said electrically conductive, resistive coating to said mirror element especially when said mirror is exposed to moisture, humidity, salt spray or solutions, or other environmental or weather conditions;

said binder material is a resinous material including a fluoroelastomer polymer;

said primer layer including acrylic and phenolic resins and amino silane; and

a layer of insulating material applied over said electrically conductive coating to protect said coating and prevent electrical shorting of the electrical circuit.