Digital electrochromic mirror system
First Claim
1. A vehicular electrochromic rearview mirror system, comprising:
- at least one electrochromic rearview mirror assembly comprising an electrochromic reflective element, wherein said electrochromic reflective element assumes a partial reflectance level in response to a signal applied thereto;
a drive circuit applying a drive signal to said electrochromic reflective element establishing a partial reflectance level thereof, said drive circuit including a digital controller and a variable source, said variable source controllably repetitively interrupting current through said variable source in response to said digital controller thereby providing a voltage reduced from a particular voltage level, said drive signal comprising said voltage reduced from said particular level; and
wherein said variable source comprises an electronic switch, wherein said electronic switch is alternatingly driven and not driven according to a duty cycle by said digital controller, and wherein said drive circuit monitors voltage across said electrochromic reflective element and varies said duty cycle at least in part as a function of the voltage across said electrochromic cell.
1 Assignment
0 Petitions
Accused Products
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.
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Citations
64 Claims
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1. A vehicular electrochromic rearview mirror system, comprising:
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at least one electrochromic rearview mirror assembly comprising an electrochromic reflective element, wherein said electrochromic reflective element assumes a partial reflectance level in response to a signal applied thereto; a drive circuit applying a drive signal to said electrochromic reflective element establishing a partial reflectance level thereof, said drive circuit including a digital controller and a variable source, said variable source controllably repetitively interrupting current through said variable source in response to said digital controller thereby providing a voltage reduced from a particular voltage level, said drive signal comprising said voltage reduced from said particular level; and wherein said variable source comprises an electronic switch, wherein said electronic switch is alternatingly driven and not driven according to a duty cycle by said digital controller, and wherein said drive circuit monitors voltage across said electrochromic reflective element and varies said duty cycle at least in part as a function of the voltage across said electrochromic cell. - View Dependent Claims (2, 3)
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4. A vehicular electrochromic rearview mirror system, comprising:
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at least one electrochromic rearview mirror assembly comprising an electrochromic reflective element, wherein said electrochromic reflective element assumes a partial reflectance level in response to a signal applied thereto; a drive circuit applying a drive signal to said electrochromic reflective element establishing a partial reflectance level thereof, said drive circuit including a digital controller and a variable source, said variable source controllably repetitively interrupting current through said variable source in response to said digital controller thereby providing a voltage reduced from a particular voltage level, said drive signal comprising said voltage reduced from said particular level; and wherein said variable source comprises an electronic switch, wherein said electronic switch is alternatingly driven and not driven according to a duty cycle by said digital controller, and wherein said drive circuit monitors voltage across said electrochromic reflective element and varies said voltage drop across said switch at least in part as a function of the voltage across the electrochromic cell. - View Dependent Claims (5, 6)
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7. A vehicular electrochromic rearview mirror system, comprising:
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at least one electrochromic rearview mirror assembly comprising an electrochromic reflective element, wherein said electrochromic reflective element assumes a partial reflectance level in response to a signal applied thereto; and a drive circuit applying a drive signal to said electrochromic reflective element establishing a partial reflectance level thereof, said drive circuit including a digital controller and a variable source, said variable source controllably repetitively interrupting current through said variable source in response to said digital controller thereby providing a voltage reduced from a particular voltage level, said drive signal comprising said voltage reduced from said particular level; wherein said drive circuit monitors voltage across said electrochromic reflective element and varies said voltage reduction at least in part as a function of the voltage across said electrochromic reflective element. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A vehicular electrochromic rearview mirror system, comprising:
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an interior electrochromic rearview mirror assembly having an interior electrochromic reflective element and at least one exterior electrochromic rearview mirror assembly having an exterior electrochromic reflective element, said interior and exterior electrochromic reflective elements exposed to different thermal environments, wherein each of said interior and exterior electrochromic reflective elements assumes a partial reflectance level in response to a signal applied thereto; and a common drive circuit applying an interior electrochromic reflective element drive signal to said interior electrochromic reflective element and an exterior reflective element drive signal to said exterior electrochromic reflective element establishing partial reflectance levels thereof, said drive circuit including a digital controller and a variable source, said variable source providing voltages reduced from a particular voltage level in response to said digital controller, said drive signals comprising said voltages reduced from said particular level; wherein said variable source repetitively interrupts current from said particular voltage level according to at least one duty cycle controlled by said digital controller, wherein said digital controller varies said at least one duty cycle as a function at least of voltage across at least one of said interior and exterior electrochromic reflective elements, wherein said drive circuit periodically monitors voltage across at least one of said interior and exterior electrochromic reflective elements at the same general time relative to said variable source interrupting current; and said drive circuit compensating said electrochromic reflective element drive signal for a thermal environment of said interior electrochromic reflective element and said exterior electrochromic reflective element drive signal for a thermal environment of said exterior electrochromic reflective element. - View Dependent Claims (26)
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27. A vehicular electrochromic rearview mirror system, comprising:
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an interior electrochromic rearview mirror assembly having an interior electrochromic reflective element and at least one exterior electrochromic rearview mirror assembly having an exterior electrochromic reflective element, said interior and exterior electrochromic reflective elements exposed to different thermal environments, wherein each of said interior and exterior electrochromic reflective elements assumes a partial reflectance level in response to a signal applied thereto; a common drive circuit applying an interior electrochromic reflective element drive signal to said interior electrochromic reflective element and an exterior reflective element drive signal to said exterior electrochromic reflective element establishing partial reflectance levels thereof, said drive circuit including a digital controller and a variable source, said variable source providing voltages reduced from a particular voltage level in response to said digital controller, said drive signals comprising said voltages reduced from said particular level, wherein said variable source comprises at least one electronic switch, wherein said digital controller controls voltage across said at least one electronic switch as a function at least of voltage across at least one of said interior and exterior electrochromic reflective elements, wherein said drive circuit periodically monitors voltage across at least one of said interior and exterior electrochromic reflective elements at the same general time relative to said variable source interrupting current; and said drive circuit compensating said electrochromic reflective element drive signal for a thermal environment of said interior electrochromic reflective element and said exterior electrochromic reflective element drive signal for a thermal environment of said exterior electrochromic reflective element. - View Dependent Claims (28)
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29. A vehicular electrochromic rearview mirror system, comprising:
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an interior electrochromic rearview mirror assembly having an interior electrochromic reflective element and at least one exterior electrochromic rearview mirror assembly having an exterior electrochromic reflective element, said interior and exterior electrochromic reflective elements exposed to different thermal environments, wherein each of said interior and exterior electrochromic reflective elements assumes a partial reflectance level in response to a signal applied thereto; a common drive circuit applying an interior electrochromic reflective element drive signal to said interior electrochromic reflective element and an exterior reflective element drive signal to said exterior electrochromic reflective element establishing partial reflectance levels thereof, said drive circuit including a digital controller and a variable source, said variable source providing voltages reduced from a particular voltage level in response to said digital controller, said drive signals comprising said voltages reduced from said particular level, wherein said variable source comprises at least one electronic switch, wherein said digital controller controls voltage across said at least one electronic switch and a duty cycle of said at least one electronic switch as a function at least of voltage across at least one of said interior and exterior electrochromic reflective elements, wherein said drive circuit periodically monitors voltage across at least one of said interior and exterior electrochromic reflective elements at the same general time relative to said variable source interrupting current; and said drive circuit compensating said electrochromic reflective element drive signal for a thermal environment of said interior electrochromic reflective element and said exterior electrochromic reflective element drive signal for a thermal environment of said exterior electrochromic reflective element. - View Dependent Claims (30)
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31. A vehicular electrochromic rearview mirror system, comprising:
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an interior electrochromic rearview mirror assembly having an interior electrochromic reflective element and at least one exterior electrochromic rearview mirror assembly having an exterior electrochromic reflective element, said interior and exterior electrochromic reflective elements exposed to different thermal environments, wherein each of said interior and exterior electrochromic reflective elements assumes a partial reflectance level in response to a signal applied thereto; a common drive circuit applying an interior electrochromic reflective element drive signal to said interior electrochromic reflective element and an exterior reflective element drive signal to said exterior electrochromic reflective element establishing partial reflectance levels thereof, said drive circuit including a digital controller and a variable source, said variable source providing voltages reduced from a particular voltage level in response to said digital controller, said drive signals comprising said voltages reduced from said particular level; and said drive circuit compensating said electrochromic reflective element drive signal for a thermal environment of said interior electrochromic reflective element and said exterior electrochromic reflective element drive signal for a thermal environment of said exterior electrochromic reflective element, wherein said compensating includes monitoring voltages across said interior and exterior electrochromic reflective elements and adjusting said variable source as a function of the voltages across said interior and exterior electrochromic reflective elements thereby compensating for said different thermal environments of said interior and exterior electrochromic reflective elements. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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45. A vehicular electrochromic rearview mirror system, comprising:
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at least one electrochromic rearview mirror assembly having an electrochromic reflective element, wherein said at least one electrochromic reflective element assumes a partial reflectance level in response to a signal applied thereto, wherein said electrochromic reflective element requires that a signal applied thereto not exceed a maximum voltage for more than a predetermined time period; a drive circuit applying a drive signal to said electrochromic reflective element establishing a partial reflectance level thereof, said drive circuit including a variable source, said variable source providing a voltage reduced from a particular voltage level, said drive signal comprising said voltage reduced from said particular level; said drive circuit monitoring voltage across said electrochromic reflective element and controlling said variable source at least in part as a function of the voltage across said electrochromic reflective element in order to ensure that said drive signal does not exceed said maximum voltage for more than said predetermined time period. - View Dependent Claims (46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64)
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Specification