Oscillating photovoltaic optical shutter for reflective display
First Claim
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1. An optical shutter operated device for modulating incident light passing through said optical shutter, comprising:
- electrically operable optical shutter means, said shutter means having a first, relatively greater light transmissive operating condition and a second, relatively lesser light transmissive operating condition; and
photovoltaic means coupled to said optical shutter means, said photovoltaic means receiving light energy from said incident light passing through said optical shutter means for providing a cyclical electrical output for causing said shutter means to alternate between said first and second operating conditions, all electrical power required for operating said optical shutter means being directly supplied by photovoltaic conversion of said light energy.
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Abstract
An optical shutter operated device includes a reflector to reflect incident light and a liquid crystal light shutter interposed in front of the reflector. A photovoltaic cell is disposed behind the shutter and is illuminated by the incident light thereby supplying a control voltage to the liquid crystal light shutter for causing it to alternate cyclically between a relatively transparent state and a relatively opaque state.
71 Citations
25 Claims
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1. An optical shutter operated device for modulating incident light passing through said optical shutter, comprising:
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electrically operable optical shutter means, said shutter means having a first, relatively greater light transmissive operating condition and a second, relatively lesser light transmissive operating condition; and photovoltaic means coupled to said optical shutter means, said photovoltaic means receiving light energy from said incident light passing through said optical shutter means for providing a cyclical electrical output for causing said shutter means to alternate between said first and second operating conditions, all electrical power required for operating said optical shutter means being directly supplied by photovoltaic conversion of said light energy. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. Reflector apparatus for providing a time varying reflection of light incident thereon, comprising:
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reflector means; electrically operable liquid crystal optical shutter means disposed for intercepting incident light travelling towards said reflector means; photovoltaic means connected to said electrically operable liquid crystal optical shutter means, said photovoltaic means oriented for receiving said incident light and being the sole source of operative power by photovoltaic conversion of said incident light for said electrically operable liquid crystal optical shutter means; and at least a portion of said electrically operable liquid crystal optical shutter means being disposed for intercepting said incident light travelling towards said photovoltaic means. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. Reflector apparatus comprising:
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reflector means for reflecting incident light; said incident light originating from a source; photovoltaic means disposed for being illuminated by said incident light to provide an output power signal derived directly from said incident light only when illuminated by said incident light; and electrically operable liquid crystal light shutter means coupled to said photovoltaic means, a first portion of said light shutter means being disposed between said source and said reflector means and a second portion thereof being disposed between said source and said photovoltaic means, and wherein all operating power for said electrically operable liquid crystal light shutter means is provided by said photovoltaic means to enable said shutter to be in an opaque state during the presence of said output power signal thereby causing said electrically operable liquid crystal light shutter to oscillate between a transparent state and said opaque state. - View Dependent Claims (19)
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20. Reflector apparatus comprising:
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retro-reflector means for receiving incident light; light shutter means interposed in front of said retro-reflector means; and photovoltaic cell means coupled to said light shutter means and disposed for being illuminated by said incident light passing through said light shutter means to provide a power output operating signal having a power level derived photoelectrically from said incident light, and for supplying said signal to said light shutter means as a sole source of operating power thereby causing said light shutter means to operate alternately between a relatively transparent state and a relatively opaque state.
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21. Reflector apparatus for use with a reflective sign, comprising:
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photovoltaic means responsive to incident light for providing a control voltage when said incident light impinges thereon, said control voltage having a power level derived solely from said incident light; and electrically operable light shutter means coupled to said photovoltaic means for alternately blocking and transmitting light between said reflective sign and a viewing region in front of said reflector apparatus and between said photovoltaic means and said viewing region, only during the presence of said control voltage whereby said photovoltaic means supplies said control voltage to said electrically operable light shutter means to cause light to be alternately blocked and transmitted solely upon the presence of said incident light. - View Dependent Claims (22, 23)
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24. An optical shutter operated device for modulating incident light, comprising:
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photovoltaic cell means oriented for being illuminated by said incident light to provide a control voltage when illuminated; optical shutter means coupled to said photovoltaic cell means, said shutter means being operative in a first state to enable incident light to pass therethrough and in a second state to restrict the passage of light so as to modulate light reaching said photovoltaic cell means to cause said control voltage to be alternately provided to thereby form an oscillatory closed loop having a frequency of oscillation according to the modulation of said shutter means, whereby said control voltage has a power level derived by photoelectric conversion of said incident light and is provided only during said first state of said shutter means. - View Dependent Claims (25)
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Specification