Radiant energy – Photocells; circuits and apparatus – Photocell controlled circuit
Reexamination Certificate
1999-07-22
2002-02-12
Lee, John R. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Photocell controlled circuit
C333S181000, C359S267000, C359S843000
Reexamination Certificate
active
06346698
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention generally relates to a mirror assembly having an electrically adjustable reflectivity, and more specifically to a mirror assembly that provides for the simultaneous display of a vehicle heading and an external temperature.
Mirror systems are known in the art that include a reflective element having a transmissive element of variable transmittance and a reflective surface disposed behind the transmissive element. Those mirror systems have used a drive signal coupled to the transmissive element of the mirror system so as to variably attenuate the reflectance of the mirror system. Typically, the transmissive element has included an electrochromic element. Examples of such mirror systems are disclosed in U.S. Pat. No. 4,902,108, entitled “SINGLE-COMPARTMENT, SELF-ERASING, SOLUTION-PHASE ELECTROCHROMIC DEVICES SOLUTIONS FOR USE THEREIN, AND USES THEREOF,” issued Feb. 20, 1990, to H. J. Byker; Canadian Patent No. 1,300,945, entitled “AUTOMATIC REARVIEW MIRROR SYSTEM FOR AUTOMOTIVE VEHICLES,” issued May 19, 1992, to J. H. Bechtel et al.; U.S. Pat. No. 5,128,799, entitled “VARIABLE REFLECTANCE MOTOR VEHICLE MIRROR,” issued Jul. 7, 1992, to H. J. Byker; U.S. Pat. No. 5,202,787, entitled “ELECTRO-OPTIC DEVICE,” issued Apr. 13, 1993, to H. J. Byker et al.; U.S. Pat. No. 5,204,778, entitled “CONTROL SYSTEM FOR AUTOMATIC REARVIEW MIRRORS,” issued Apr. 20, 1993, to J. H. Bechtel; U.S. Pat. No. 5,278,693, entitled “TINTED SOLUTION-PHASE ELECTROCHROMIC MIRRORS,” issued Jan. 11, 1994, to D. A. Theiste et al.; U.S. Pat. No. 5,280,380, entitled “UV-STABILIZED COMPOSITIONS AND METHODS,” issued Jan. 18, 1994, to H. J. Byker; U.S. Pat. No. 5,282,077, entitled “VARIABLE REFLECTANCE MIRROR,” issued Jan. 25, 1994, to H. J. Byker; U.S. Pat. No. 5,294,376, entitled “BIPYRIDINIUM SALT SOLUTIONS,” issued Mar. 15, 1994, to H. J. Byker; U.S. Pat. No. 5,336,448, entitled “ELECTROCHROMIC DEVICES WITH BIPYRIDINIUM SALT SOLUTIONS,” issued Aug. 9, 1994, to H. J. Byker; U.S. Pat. No. 5,434,407, entitled “AUTOMATIC REARVIEW MIRROR INCORPORATING LIGHT PIPE,” issued Jan. 18, 1995, to F. T. Bauer et al.; U.S. Pat. No. 5,448,397, entitled “OUTSIDE AUTOMATIC REARVIEW MIRROR FOR AUTOMOTIVE VEHICLES,” issued Sep. 5, 1995, to W. L. Tonar; and U.S. Pat. No. 5,451,822, entitled “ELECTRONIC CONTROL SYSTEM,” issued Sep. 19, 1995, to J. H. Bechtel et al. Each of these patents is commonly assigned with the present invention and the disclosures of each, including the references contained therein, are hereby incorporated herein in their entirety by reference.
Optical display devices have also been provided behind the reflective element of such mirror systems in order to produce a single visual display of various information. Those optical display devices have typically been adapted to be viewed through the mirror system and have displayed various information which has included a vehicle direction, a time, or a temperature.
Various types of optical display devices have been utilized with mirror systems. For example, the optical display device could be an electroluminescent device, a vacuum fluorescent display, a light emitting diode (LED), semiconductor laser, incadescent, back-lit crystal display, cathode ray tube, or any number of other display technologies. In addition, multiple display devices have been implemented in the bezel of prior art rearview mirror assemblies.
While mirror systems have been disclosed in literature as having displays on which a wide variety of information is simultaneously displayed, such mirror systems have not been commercially practical due to their high levels of electromagnetic interference (EMI) or high cost. Auto manufacturers have imposed relatively strict limits on the EMI levels exhibited by interior rearview mirrors due to their close proximity to the radio antenna and other sensitive electronic equipment in the vehicle's instrument panel. Currently, the EMI levels for a rearview mirror must typically be less than the limits in FIG.
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. Thus, mirror systems that have been commercially implemented have typically displayed only the vehicle heading or the external temperature at one time or use a non-multiplexed display which increases size and cost, so as to keep the EMI levels within acceptable limits.
SUMMARY OF THE INVENTION
An embodiment of the present invention is directed to a mirror assembly having an electrically adjustably reflectivity. The mirror assembly 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 an electromagnetic interference level within acceptable limits. In addition, a single display driver is utilized to update the dual display such that the expense of using two display drivers is avoided.
These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.
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Mirror, Speak to Me, Popular Science, Apr. 1998, p. 15.
Autolink Rear-View Mirror, AI, Feb. 1998, p. 157.
Newaves, 2. Johnson Controls and Highway Master Corp. rearview mirror; Blow-up of item 2, Mar. 1998, (2 pages).
Gentex Corporation
Lee John R.
Price Heneveld Cooper DeWitt & Litton
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