Back to results
US 2009/0153208 A1Published application
Pulse Width Modulation Driver for Electroactive Lens
AssigneeSupertex, Inc.
InventorScott Lynch
Life of this patent
Estimating the term…
Abstract
An electroactive lens driver generates a variable root-mean-square drive voltage for controlling an electroactive lens by controlling the duty cycle of a modified square wave.
Claims19
An electroactive lens driver comprising:
- means for generating a pulse width modulated waveform;
- and
- means for coupling said means for generating to an electroactive lens for pulse width modulating a power signal applied to the electroactive lens.
An electroactive lens driver comprising:
- an H-bridge output stage comprising four controlled switches, the H-bridge output stage including output nodes for coupling to an electroactive lens;
- and
- a pulse width modulator coupled to the H-bridge output stage and providing a control voltage signal thereto to control the H-bridge output stage to provide a pulsed voltage signal to the electroactive lens and to vary a duty cycle of the pulsed voltage signal in response to the control voltage signal.
An electroactive lens driver comprising:
- a half-bridge comprising a pair of switches and including an output terminal for coupling to an electroactive lens;
- a controlled switch coupled between a mid-point of the half-bridge and circuit common;
- and
- a pulse width modulator to control the half-bridge and the controlled switch coupled to the circuit common to provide a pulsed voltage signal to the electroactive lens in response to a pair of external voltage signals and to vary a duty cycle of the pulsed voltage signal.
1 more element
A method for generating control signals for an electroactive lens, the method comprising:
- generating a first control signal to open a first plurality of switches and close a second plurality of switches in an H-bridge output stage coupled to the electroactive lens to apply a positive voltage across the electroactive lens;
- generating a second control signal to close the first plurality of switches and open the second plurality of switches in the H-bridge output stage to apply a negative voltage across the electroactive lens;
- and
- controlling the generating of the first and second control signal to vary the duty cycle of the positive and negative voltages applied to the electroactive lens.
1 more element
A method of operating an electroactive lens, the method comprising:
- generating a constant voltage source;
- generating a first control signal to open a first switch and closing a second switch in a switch matrix coupling the constant voltage source to the electroactive lens to apply a positive voltage from the constant voltage source across the electroactive lens;
- generating a second control signal to close the first switch and open the second switch in the switch matrix to apply a negative voltage from the constant voltage source across the electroactive lens;
- and
- generating a third control signal supplied to the switch matrix to vary the duty cycle of the positive and negative voltages and the time period therebetween applied to the electroactive lens.
2 more elements
Dependencies are inferred from the claim text.