Electrochromic device capable of prolonged coloration
First Claim
1. A variable electrochromic light transmission system comprising:
- an electrochromic element having a continuously variable transmission characteristic;
said element being responsive to a momentary application of a signal by coloring to a partial light transmission level and being responsive to removal of said signal by maintaining a transmission level that is within a given percentage from said partial transmission level;
said partial light transmission level selectable from a continuum of light transmission levels in a range from a highest light transmission level to a lowest light transmission level;
input means for selecting a light transmission level of said electrochromic element;
circuit means responsive to said input means for intermittently applying a drive signal to said electrochromic element in successive pulses separated by holding periods;
said drive signal having a level corresponding to the selected light transmission level; and
said circuit means being responsive to at least one of the magnitude and the rate of change of magnitude of said input means to provide momentary overshoot of said drive signal level upon a change in said input means that increases said drive signal level and momentary undershoot of said drive signal upon a change in said input means that decreases said drive signal level.
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Accused Products
Abstract
An elecctrochromic system utilizes the benefit both from the continuous variability in transmission and memory in EC devices to provide a partial level of light transmission that is variable while minimizing energy usage. An electrochromic element that is responsive to a momentary application of a signal by coloring to a corresponding partial transmission level and maintaining at that level for a given period of time after removal of the drive signal, is provided with a drive signal. The drive signal has a value corresponding to a selected transmission level and is applied for a first predetermined period of time in order to color the electrochromic element to the selected transmission level and repetitively thereafter for the same or shorter periods of time. The subsequent periods are separated from each other and from the first period by holding periods of time during which the drive signal is not applied. A reset circuit resets the drive circuit to apply the changed value of the drive signal in response to changes in the selected light transmission level. An additional circuit may be provided that is responsive to the magnitude and/or rate of change of magnitude of the selected light transmission level in order to provide momentary overshoot of the drive signal level upon a change that increases the drive signal level and a momentary undershoot of the drive signal upon a change that decreases the drive signal level.
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Citations
39 Claims
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1. A variable electrochromic light transmission system comprising:
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an electrochromic element having a continuously variable transmission characteristic; said element being responsive to a momentary application of a signal by coloring to a partial light transmission level and being responsive to removal of said signal by maintaining a transmission level that is within a given percentage from said partial transmission level; said partial light transmission level selectable from a continuum of light transmission levels in a range from a highest light transmission level to a lowest light transmission level; input means for selecting a light transmission level of said electrochromic element; circuit means responsive to said input means for intermittently applying a drive signal to said electrochromic element in successive pulses separated by holding periods; said drive signal having a level corresponding to the selected light transmission level; and said circuit means being responsive to at least one of the magnitude and the rate of change of magnitude of said input means to provide momentary overshoot of said drive signal level upon a change in said input means that increases said drive signal level and momentary undershoot of said drive signal upon a change in said input means that decreases said drive signal level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A variable light transmission system comprising:
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an electrochromic element having a continuously variable light transmission characteristic; said electrochromic element being responsive to a momentary application of a signal by coloring to a partial light transmission level and being responsive to removal of said signal by maintaining a light transmission level that is within a given percentage from the partial light transmission level for a given period of time defining a memory time constant for said electrochromic element; said partial light transmission level being selectable from a continuum of light transmission levels from a highest light transmission level to a lowest light transmission level; input means for selecting a light transmission level of said electrochromic element; and circuit means responsive to said input means for applying to said electrochromic element a value of said signal corresponding to the selected light transmission level, said circuit means applying said selected signal value for a first period of time in order to color said electrochromic element to said selected light transmission level and repetitively thereafter for second periods of time in order to maintain said selected light transmission level, said second periods being separated from said first period and from each other by holding periods of time during which said selected signal is not applied to said electrochromic element, said first period of time being at least approximately 100 seconds. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A variable light transmission system comprising:
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an electrochromic element having a continuously variable transmission characteristic; said electrochromic element being responsive to a momentary application of a first signal having a particular polarity by coloring to a partial light transmission level and being responsive to a momentary application of a second signal not having said particular polarity by bleaching to a high light transmission level, said electrochromic element responsive to removal of said signals by maintaining a light transmission level that is within a given percentage from the selected light transmission level for a given period of time defining a memory time constant for said electrochromic element; said partial light transmission level being selectable from a continuum of light transmission levels from said highest light transmission level to a lowest light transmission level; input means for selecting one of said first signal and said second signal; and circuit means responsive to said input means selecting one of said first and second signals in order to achieve one of coloring said electrochromic element to a partial light transmission level or bleaching said electrochromic element to a high light transmission level, said circuit means applying to said electrochromic element a selected value of one of said signals corresponding to a partial light transmission level for a first period of time in order to color said electrochromic element to a partial light transmission level and repetitively thereafter for second periods of time in order to maintain the selected partial light transmission level, said second periods being separated from said first period and from each other by holding periods of time during which the selected signal is not applied to said electrochromic element, said circuit means applying to said electrochromic element the other of said signals to bleach said electrochromic element to a high light reflectance level. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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Specification