Abstract: An electronic compass is described for use in vehicles. The compass employs a magnetoresistive sensor for sensing the earth magnetic field and the sensor is operated in alternate set/reset bias modes. In a first embodiment, the compass is provided with deviation compensation by a closed loop system including measurement of the sensor output signals and an offset current strap for nullifying the vehicle deviation field. In a second embodiment, deviation compensation is provided by operation in an initial calibration mode and by operation in a normal compensation mode to adjust compensation, as needed, on a long term basis during normal operation of the compass. In the initial calibration mode, while the vehicle is being driven, the signal peak values are adjusted to a nominal earth field level by changing the offset current. Then, compensating signal reference values for each axis are determined as each peak for that axis is determined.

Abstract: A vehicular rearview mirror system and method of controlling the vehicle rearview mirror system including establishing a most-dimmed reflectance level of the interior mirror reflective element that is higher than a most-dimmed reflectance level of the exterior mirror reflectance level, the establishment being a function of the rear window light transmission value. The establishment may be a function of sampling of light sensed by at least one light sensor in the passenger compartment that is directed toward the rear-viewing rear window to receive light passing through the rearward-viewing rear window.

Abstract: An electronic compass is described for use in vehicles. The compass employs a magnetoresistive sensor for sensing the earth magnetic field and the sensor is operated in alternate set/reset bias modes. In a first embodiment, the compass is provided with deviation compensation by a closed loop system including measurement of the sensor output signals and an offset current strap for nullifying the vehicle deviation field. In a second embodiment, deviation compensation is provided by operation in an initial calibration mode and by operation in a normal compensation mode to adjust compensation, as needed, on a long term basis during normal operation of the compass. In the initial calibration mode, while the vehicle is being driven, the signal peak values are adjusted to a nominal earth field level by changing the offset current. Then, compensating signal reference values for each axis are determined as each peak for that axis is determined.

Abstract: A vehicular electrochromic rearview mirror system includes an interior electrochromic rearview mirror assembly and at least one exterior electrochromic rearview mirror assembly. Each mirror assembly includes an electrochromic reflective element that assumes a partial reflectance level in response to a signal applied thereto. A drive circuit applies a drive signal to each of the electrochromic reflective elements. The drive circuit may include a digital controller, a master drive circuit responsive to the digital controller to apply a first drive signal to one of the electrochromic reflective elements and a slave drive circuit responsive to the digital controller to apply a second drive signal to a second of the electrochromic reflective elements. The second drive signal may be derived from the first drive signal. The drive circuit may include a digital controller and a switching power supply controlled by the digital controller to produce a drive signal.

Abstract: A vehicular electrochromic rearview mirror system includes an interior electrochromic rearview mirror assembly and at least one exterior electrochromic rearview mirror assembly. Each mirror assembly includes an electrochromic reflective element that assumes a partial reflectance level in response to a signal applied thereto. A drive circuit applies a drive signal to each of the electrochromic reflective elements. The drive circuit may include a digital controller, a master drive circuit responsive to the digital controller to apply a first drive signal to one of the electrochromic reflective elements and a slave drive circuit responsive to the digital controller to apply a second drive signal to a second of the electrochromic reflective elements. The second drive signal may be derived from the first drive signal. The drive circuit may include a digital controller and a switching power supply controlled by the digital controller to produce a drive signal.

Abstract: An electrochromic rearview mirror system for a vehicle includes an electrochromic reflective element having an electrochromic cell, wherein the reflective element colors to a partial reflectance level in response to a drive signal applied to the cell. The rearview mirror assembly additionally includes a drive circuit which applies a pulsed drive signal to the electrochromic cell in order to establish the partial reflectance level of the reflective element. The drive circuit controls the partial reflectance level as a function of the duty cycle of the pulsed drive signal, which has a pulse repetition rate of at least approximately 10 cycles per second and preferably at least approximately 20 cycles per second. The drive circuit additionally adjusts the amplitude of the pulses as a function of the voltage developed across the electrochromic cell.

Abstract: An adaptive light-responsive vehicle control, such as an electro-optic rearview mirror system, and a method of adapting a light-responsive vehicle control to a vehicle which accommodates variations in vehicle configuration includes providing at least one light sensor receiving light passing through the vehicle rear window and monitoring this light sensor, such as for an extended period of time. At least one operating parameter, such as sensitivity, of the light-responsive vehicle control is established as a result of the monitoring. This allows the same light-responsive vehicle control to be used with both tinted and non-tinted rear windows.

Abstract: A vehicle control system comprises an industry standard CAN network with a number of nodes distributed around the vehicle for controlling corresponding parts of the vehicle. One such node is located in the housing of the vehicle interior rearview mirror and directly controls the reflectivity of an electro-optic mirror unit, in accordance with the state of at least one ambient light sensor and a remote keyless entry device. The node also communicates via an ISO9141 interface with a number of slave controllers such as a sun-roof control module mounted adjacent a sun-roof and a roof control module mounted in a roof housing. By this means the UCM exercises indirect control of the sun-roof in accordance with the state of a switch, and exercises indirect control of various lamps GEN1, GEN2, FLL and FRL in the roof housing in accordance with the state of switches Gen, FL and FR mounted in the roof housing or, in the case of the lamps GEN1 and GEN2, when a vehicle door is opened.

Abstract: An electrochromic rearview mirror system for a vehicle includes an electrochromic reflective element having an electrochromic cell, wherein the reflective element colors to a partial reflectance level in response to a drive signal applied to the cell. The rearview mirror assembly additionally includes a drive circuit which applies a pulsed drive signal to the electrochromic cell in order to establish the partial reflectance level of the reflective element. The drive circuit controls the partial reflectance level as a function of the duty cycle of the pulsed drive signal, which has a pulse repetition rate of at least approximately 10 cycles per second and preferably at least approximately 20 cycles per second. The drive circuit additionally adjusts the amplitude of the pulses as a function of the voltage developed across the electrochromic cell.

Abstract: An electrochromic rearview mirror system for a vehicle includes an electrochromic reflective element having an electrochromic cell, wherein the reflective element colors to a partial reflectance level in response to a drive signal applied to the cell. The rearview mirror assembly additionally includes a drive circuit which applies a pulsed drive signal to the electrochromic cell in order to establish the partial reflectance level of the reflective element. The drive circuit controls the partial reflectance level as a function of the duty cycle of the pulsed drive signal, which has a pulse repetition rate of at least approximately 10 cycles per second and preferably at least approximately 20 cycles per second. The drive circuit additionally adjusts the amplitude of the pulses as a function of the voltage developed across the electrochromic cell.

Abstract: A vehicular electrochromic rearview mirror system is provided including an interior electrochromic rearview mirror assembly and at least one exterior electrochromic rearview mirror assembly. The interior rearview mirror assembly has an interior electrochromic reflective element that assumes a partial reflectance level in response to a first drive signal applied thereto. The exterior rearview mirror assembly has an exterior electrochromic reflective element that assumes a partial reflectance level in response to a second drive signal applied thereto. A drive circuit is provided that supplies a first drive signal to the interior electrochromic reflective element and a second drive signal to the exterior electrochromic reflective element. The drive circuit variably controls a relationship between the partial reflectance levels of the interior reflective element and the exterior electrochromic reflective element by a control signal.

Abstract: A vehicle control system comprises an industry standard CAN network with a number of nodes distributed around the vehicle for controlling corresponding parts of the vehicle. One such node is located in the housing of the vehicle interior rearview mirror and directly controls the reflectivity of an electro-optic mirror unit, in accordance with the state of at least one ambient light sensor and a remote keyless entry device. The node also communicates via an ISO9141 interface with a number of slave controllers such as a sun-roof control module mounted adjacent a sun-roof and a roof control module mounted in a roof housing. By this means the UCM exercises indirect control of the sun-roof in accordance with the state of a switch, and exercises indirect control of various lamps GEN1, GEN2, FLL and FRL in the roof housing in accordance with the state of switches Gen, FL and FR mounted in the roof housing or, in the case of the lamps GEN1 and GEN2, when a vehicle door is opened.

Abstract: A vehicular electrochromic rearview mirror system includes an interior electrochromic rearview mirror assembly and at least one exterior electrochromic rearview mirror assembly. Each mirror assembly includes an electrochromic reflective element that assumes a partial reflectance level in response to a signal applied thereto. A drive circuit applies a drive signal to each of the electrochromic reflective elements. The drive circuit may include a digital controller, a master drive circuit responsive to the digital controller to apply a first drive signal to one of the electrochromic reflective elements and a slave drive circuit responsive to the digital controller to apply a second drive signal to a second of the electrochromic reflective elements. The second drive signal may be derived from the first drive signal. The drive circuit may include a digital controller and a switching power supply controlled by the digital controller to produce a drive signal.

Abstract: A vehicular electrochromic rearview mirror system includes an interior electrochromic rearview mirror assembly and at least one exterior electrochromic rearview mirror assembly. Each mirror assembly includes an electrochromic reflective element that assumes a partial reflectance level in response to a signal applied thereto. A drive circuit applies a drive signal to each of the electrochromic reflective elements. The drive circuit may include a digital controller, a master drive circuit responsive to the digital controller to apply a first drive signal to one of the electrochromic reflective elements and a slave drive circuit responsive to the digital controller to apply a second drive signal to a second of the electrochromic reflective elements. The second drive signal may be derived from the first drive signal. The drive circuit may include a digital controller and a switching power supply controlled by the digital controller to produce a drive signal.

Abstract: An electronic compass is described for use in vehicles. The compass employs a magnetoresistive sensor for sensing the earth magnetic field and the sensor is operated in alternate set/reset bias modes. In a first embodiment, the compass is provided with deviation compensation by a closed loop system including measurement of the sensor output signals and an offset current strap for nullifying the vehicle deviation field. In a second embodiment, deviation compensation is provided by operation in an initial calibration mode and by operation in a normal compensation mode to adjust compensation, as needed, on a long term basis during normal operation of the compass. In the initial calibration mode, while the vehicle is being driven, the signal peak values are adjusted to a nominal earth field level by changing the offset current. Then, compensating signal reference values for each axis are determined as each peak for that axis is determined.

Abstract: An electrochromic rearview mirror system for a vehicle includes an electrochromic reflective element having an electrochromic cell, wherein the reflective element colors to a partial reflectance level in response to a drive signal applied to the cell. The rearview mirror assembly additionally includes a drive circuit which applies a pulsed drive signal to the electrochromic cell in order to establish the partial reflectance level of the reflective element. The drive circuit controls the partial reflectance level as a function of the duty cycle of the pulsed drive signal, which has a pulse repetition rate of at least approximately 10 cycles per second and preferably at least approximately 20 cycles per second. The drive circuit additionally adjusts the amplitude of the pulses as a function of the voltage developed across the electrochromic cell.

Abstract: A vehicular electrochromic rearview mirror system includes an interior electrochromic rearview mirror assembly and at least one exterior electrochromic rearview mirror assembly. Each mirror assembly includes an electrochromic reflective element that assumes a partial reflectance level in response to a signal applied thereto. A drive circuit applies a drive signal to each of the electrochromic reflective elements. The drive circuit may include a digital controller, a master drive circuit responsive to the digital controller to apply a first drive signal to one of the electrochromic reflective elements and a slave drive circuit responsive to the digital controller to apply a second drive signal to a second of the electrochromic reflective elements. The second drive signal may be derived from the first drive signal. The drive circuit may include a digital controller and a switching power supply controlled by the digital controller to produce a drive signal.

Abstract: A light-responsive vehicle control system is provided that is useful in the passenger compartment of a vehicle having a movable top, or cover, which may be opened to at least partially uncover the passenger compartment. The control system includes at least one control circuit which receives an input from the light sensor and produces an output to operate a device, such as an electro-optic mirror or the vehicle headlights, as a function of the light sensed by the light sensor and a sensitivity value. The control circuit is responsive to the position of the cover with respect to the passenger compartment to reduce the sensitivity level when the compartment is uncovered. The control circuit may filter a signal that is a function of light sensed by the light sensor according to a time-constant and be responsive to a reduction in the light level sensed by the light sensor to reduce the value of the time-constant.

Abstract: A rearview mirror system for a vehicle having an electrochromic reflective element and heating means for uniformly heating substantially the entire reflectance surface in order to promote uniform coloration of the reflectance surface to a desired reflectance level. The reflective element is illustrated as an all solid-state electrochromic element having a large area reflectance surface for use as the exterior mirrors of a truck or other large vehicle. The application of energy to the heater can be controlled on the basis of a low ambient light condition and an ambient temperature that is low but not necessarily freezing, such as between 5.degree. C. and 20.degree. C. The heater can be resistance film that is evenly covering a surface of the reflective element and divided into first and second regions by an insulating break in the resistance film. Energy may be applied to one region in order to heat the reflectance element at a high rate to remove frost and dew.

Abstract: An electronic compass is described for use in vehicles. The compass employs a magnetoresistive sensor for sensing the earth magnetic field and the sensor is operated in alternate set/reset bias modes. In a first embodiment, the compass is provided with deviation compensation by a closed loop system including measurement of the sensor output signals and an offset current strap for nullifying the vehicle deviation field. In a second embodiment, deviation compensation is provided by operation in an initial calibration mode and by operation in a normal calibration mode to adjust compensation, as needed, on a long term basis during normal operation of the compass. In the initial calibration mode, while the vehicle is being driven, the signal peak values are adjusted to a nominal earth field level by changing the offset current. Then, compensating signal reference values for each axis are determined as each peak for that axis is determined.