Heaters for Automotive Mirrors and Rearview Assemblies Using the Same

• US 20110168687A1
• Filed: 01/12/2010
• Published: 07/14/2011
• Est. Priority Date: 01/12/2010
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Myers, Craig R., Door, Michael J.
• Granted Patent: US 8,344,288 B2
• Time in Patent Office: Days
• US Class Current: 219/202
• CPC Class Codes: B60R 1/0602 comprising means for cleaning or deicing
• CPC Class Codes: H05B 3/845 specially adapted for reflecting surfaces, e.g. bathroom - or rearview mirrors

Abstract

A vehicular rearview assembly with a heating element. The heating element is affixed behind and in thermal communication with the mirror element of the assembly. The heating element includes a plurality of heating zones that operate in alternation according to a pre-determined time-sequence. A peripheral area of the mirror element is heated up to at least as high a temperature as an inner area of the mirror element. Switching the heating zones on and off so as to have only one heating zone on at a time is determined by a controlling circuitry at least a portion of which may be separated from the assembly and disposed in a different part of the vehicle.

Claims

1. An automotive rearview assembly for use by a viewer, the assembly comprising:

a mirror element, the mirror element having a peripheral area and an inner area;

a heating element located behind the mirror element with respect to the viewer, the heating element comprising heating zones, each heating zone being in thermal contact with a corresponding area of the mirror element; and

a processor electrically connected with the heating element, the processor configured to switch a current flow among the heating zones so as to cause the heating element to heat the peripheral area to a first temperature and the inner area to a second temperature.

2. An assembly according to claim 1, wherein the processor is configured to switch a current flow in a pre-determined time sequence.

3. An assembly according to claim 1, wherein the first temperature is at least as high as the second temperature.

4. An assembly according to claim 1, wherein the first temperature is a maximum temperature of the peripheral area and the second temperature is a maximum temperature of the inner area.

5. An assembly according to claim 1, wherein the first temperature is higher than the second temperature.

6. An assembly according to claim 1, wherein the processor is further configured to switch the current flow among the heating zones so as to cause the heating element to change a temperature of the peripheral area while maintaining a temperature of the inner area.

7. An assembly according to claim 1, wherein the heating zones are configured to generate different heat outputs per unit area.

8. An assembly according to claim 1, wherein a first heating zone is arranged in a substantially surrounding relation relative to a second heating zone.

9. An assembly according to claim 1, wherein a first heating zone is located in a substantially surrounding relation with respect to a second heating zone and the processor is configured to switch the current flow between the first and second heating zones so as to cause the heating element to vary temperatures of the peripheral and inner areas according to a method that comprises

measuring, with a plurality of temperature sensors, temperature values across a surface of the mirror element;

increasing a peripheral area temperature to a first value while maintaining an inner area temperature at a second value;

increasing a peripheral area temperature to a first maximum value and an inner area temperature to a second maximum value; and

maintaining a peripheral area temperature at a first maintenance value and an inner area temperature at a second maintenance value,

wherein the first and second maintenance values are lower than the first and second maximum values and the first maximum value is at least as high as the second maximum value.

10. An assembly according to claim 9, wherein the method further comprises determining, with the processor, a temperature profile across the surface of the mirror element.

11. An assembly according to claim 1, wherein the mirror element includes an electrochromic element.

12. An automotive rearview mirror assembly for use by a viewer, the assembly comprising:

a mirror element including peripheral and inner areas;

a heating element located behind the mirror element with respect to the viewer, the heating element comprising heating zones, each heating zone being in thermal contact with a corresponding area of the mirror element, the heating zones adapted to generate heat alternatively so as to heat the peripheral area to a first temperature and the inner area to the second temperature.

13. An assembly according to claim 12, wherein the first temperature is at least as high as the second temperature.

14. An assembly according to claim 12, further comprising a processor electrically connected to the heating element, the processor configured to switch a flow of current through the heating element among the heating zones so as to cause the heating element to vary temperatures of the peripheral and inner areas in a time-sequenced fashion.

15. An assembly according to claim 12, wherein the heating zones are substantially co-extensive with the mirror element in a surface of the mirror element to which the heating element is affixed.

16. An assembly according to claim 12, wherein a first zone is arranged in a substantially surrounding relation with respect to a second zone.

17. An assembly according to claim 12, wherein a first heating zones transfers heat only to the peripheral area and a second heating zone transfers heat only to the inner area.

18. An assembly according to claim 12, wherein the heating element further includes a plurality of temperature sensors configured to measure, in real time, temperature values at different locations across a surface of the mirror element to which the heating element is affixed and to provide input data to the processor, the input data representing the measured temperature values.

19. An assembly according to claim 12, wherein the heating element further includes temperature sensors configured to measure, in real time, temperature values across a surface of the mirror element, and wherein the processor has a computer readable program code thereon, the computer readable code including program code for determining a time sequence of switching the flow of current among the heating zones on and off based on the input received from the temperature sensors.

20. A computer program product for use on a computer system for controlling temperature of a mirror element located within an automotive rearview assembly, the mirror element having peripheral and inner area, the assembly further including a heating element located behind the mirror element with respect to the viewer, the heating element comprising heating zones, each heating zone being in thermal contact with a corresponding area of the mirror element, the computer program product comprising a tangible computer-usable medium having computer readable program code stored thereon, the computer readable program code including

program code for detecting temperature values in a plurality of locations across a surface of the mirror element;

program code for determining, based on detected temperatures, a time sequence of switching a current flow among the heating zones so as to vary temperatures of the peripheral and inner areas of the mirror element from corresponding initial temperatures to corresponding maximum temperatures; and

program code for maintaining temperatures of the peripheral and inner areas of the mirror element at corresponding maintenance values after the maximum temperatures have been reached.