Low EMI multiplexed dual display

• US 20020057267A1
• Filed: 12/31/2001
• Published: 05/16/2002
• Est. Priority Date: 07/22/1999
• Status: Active Grant

• Current Assignee: Robert R. Turnbull
• Original Assignee: Robert R. Turnbull
• Inventors: Turnbull, Robert R.
• Granted Patent: US 6,552,326 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: B60R 2001/1215 with information displays
• CPC Class Codes: G02B 5/23 Photochromic filters

Abstract

A mirror assembly having an electrically adjustably reflectivity provides for the simultaneous display of a vehicle heading and an external temperature. The mirror assembly includes a reflective device, a dual display and a control circuit. The reflective device includes a transmissive element and a reflective surface formed on the transmissive element. The dual display is located behind the reflective surface of the reflective device. The dual display visually provides the vehicle heading and the external temperature through the reflective device. The control circuit provides for the variable attenuation of light through the transmissive element of the reflective device and controls the intensity and information displayed by the dual display. An advantage of the present invention is that it provides a dual display while exhibiting currently acceptable electromagnetic interference levels.

Claims

1. A mirror assembly having an electrically adjustable reflectivity and providing for the simultaneous display of information, the mirror assembly comprising:

a mounting structure;

a reflective device attached to the mounting structure, wherein the reflective device includes a transmissive element and a reflective surface formed on the transmissive element;

a multiple element display for visually providing the information attached to the mounting structure; and

a control circuit which provides for the variable attenuation of light through the transmissive element and controls the intensity and the information displayed by the multiple element display, the control circuit sequentially providing the information to the multiple element display, the control circuit exhibiting an electromagnetic interference level less than about 41 dBuV/m for emissions in the frequency range from about 0.4 MHz to about 20 MHz.

2. The mirror assembly of claim 1, wherein the control circuit further includes:

a first power supply filter coupled between a first power supply and a multiple element display driver; and

a second power supply filter coupled between a second power supply and the multiple element display,

and wherein the first and second power supply filters function to reduce the electromagnetic interference level exhibited by the control circuit.

3. The mirror assembly of claim 2, wherein the second power supply is derived from the first power supply.

4. The mirror assembly of claim 1, wherein the control circuit further includes:

a light sensor which senses ambient and glare light levels;

a multiple element display driver which provides information signals to the multiple element display; and

an intensity circuit which adjusts the reflectivity of the reflective device and intensity of the multiple element display responsive to the light sensor.

5. The mirror assembly of claim 4, wherein the electromagnetic interference level exhibited by the control circuit is less than about 28 dBuV/m for narrowband emissions in the frequency range from about 0.4 MHz to about 20 MHz.

6. The mirror assembly of claim 1, wherein the information includes a vehicle heading and an external temperature.

7. The mirror assembly of claim 1, wherein the reflectivity of the reflective device is adjusted based on an ambient light level.

8. The mirror assembly of claim 1, wherein the reflectivity of the reflective device is adjusted based on a glare light level.

9. The mirror assembly of claim 1, where the reflectivity of the reflective device is adjusted based on both an ambient light level and a glare light level.

10. The mirror assembly of claim 1, wherein the intensity of the multiple element display is adjusted based on an ambient light level.

11. The mirror assembly of claim 1, wherein the intensity of the multiple element display is adjusted based on a glare light level.

12. The mirror assembly of claim 1, where the intensity of the multiple element display is adjusted based on both an ambient light level and a glare light level.

13. The mirror assembly of claim 1, wherein the reflective surface includes a window opening through which the multiple element display is visible.

14. The mirror assembly of claim 1, wherein the reflective surface includes a window opening in which the reflective surface is partially removed such that the multiple element display is visible.

15. The mirror assembly of claim 1, wherein the transmissive element includes an electrochromic medium.

16. The mirror assembly of claim 1, wherein the multiple element display is a vacuum fluorescent display.

18. The mirror assembly of claim 17, wherein the multiple element display is located behind the reflective surface of the reflective device and visually provides the information through a window opening in the reflective surface of the reflective device.

19. The mirror assembly of claim 17, wherein the control circuit exhibits an electromagnetic interference level less than about 15 dBuV/m for narrowband emissions in the frequency range from about 20 MHz to about 375 MHz.

20. The mirror assembly of claim 17, wherein the control circuit exhibits an electromagnetic interference level less than about 41 dBuV/m for broadband emissions in the frequency range from about 0.4 MHz to about 20 MHz.

21. The mirror assembly of claim 17, wherein the control circuit exhibits an electromagnetic interference level less than about 28 dBuV/m for broadband emissions in the frequency range from about 20 MHz to about 75.167 MHz.

22. The mirror assembly of claim 17, wherein the control circuit exhibits an electromagnetic interference level less than about 38 dBuV/m for broadband emissions in the frequency range from about 75.167 MHz to about 119.132 MHz.

23. The mirror assembly of claim 17, wherein the control circuit exhibits an electromagnetic interference level less than about 28 dBuV/m for broadband emissions in the frequency range from about 119.132 MHz to about 375 MHz.

24. The mirror assembly of claim 17, wherein the information includes a vehicle heading and an external temperature.

26. The mirror assembly of claim 25, wherein the multiple element display is located behind the reflective surface of the reflective device and visually provides the information through a window opening in the reflective surface of the reflective device.

27. The mirror assembly of claim 25, wherein the information includes a vehicle heading and an external temperature.

17. A mirror assembly having an electrically adjustable reflectivity and providing for the simultaneous display of information, the mirror assembly comprising:

a mounting structure;

a reflective device attached to the mounting structure, wherein the reflective device includes a transmissive element and a reflective surface formed on the transmissive element;

a multiple element display for visually providing the information attached to the mounting structure; and

a control circuit which provides for the variable attenuation of light through the transmissive element and controls the intensity and the information displayed by the multiple element display, the control circuit sequentially providing the information to the multiple element display, the control circuit exhibiting an electromagnetic interference level less than about 28 dBuV/m for narrowband emissions in the frequency range from about 0.4 MHz to about 20 MHz.

25. A mirror assembly having an electrically adjustable reflectivity and providing for the simultaneous display of information, the mirror assembly comprising:

a mounting structure;

a reflective device attached to the mounting structure, wherein the reflective device includes a transmissive element and a reflective surface formed on the transmissive element;

a multiple element display for visually providing the information attached to the mounting structure; and

a control circuit which provides for the variable attenuation of light through the transmissive element and controls the intensity and the information displayed by the multiple element display, the control circuit sequentially providing the information to the multiple element display, the control circuit exhibiting an electromagnetic interference level less than about 41 dBuV/m for broadband emissions in the frequency range from about 0.4 MHz to about 20 MHz and an electromagnetic interference level less than about 15 dBuV/m for narrowband emissions in the frequency range from about 0.4 MHz to about 20 MHz.