Ultrasonic lens cleaning system with foreign material detection
AssigneeTexas Instruments Incorporated
InventorsDavid Patrick Magee, Stephen John Fedigan
Life of this patent
Estimating the term…
Abstract
Disclosed examples include lens cleaning systems, drivers and operating methods, including a transducer mechanically coupled to a lens, a driver to provide an oscillating drive signal to the transducer and a controller to control the drive signal frequency to vibrate the lens at frequencies in a range of interest. The controller determines a measured resonant frequency of the lens cleaning system in the range of interest according to a transducer feedback signal and selectively performs a lens cleaning operation if the measured resonant frequency differs from a baseline resonant frequency of the lens cleaning system for a clean lens.
Claims17
Apparatus comprising:
- a driver having a driver output adapted to be coupled through a transducer to a lens, the driver including:
- a feedback circuit having a feedback input and a feedback output, the feedback input coupled to the driver output, and the feedback circuit configured to provide a feedback signal at the feedback output responsive to the feedback input, the feedback signal representing an electrical property of the transducer;
- and
- a controller coupled between the feedback output and the driver output, the controller configured to:
- provide an oscillating drive signal at the driver output for causing the transducer to vibrate the lens at frequencies within a frequency range;
- responsive to the feedback signal, determine a resonant frequency of the lens within the frequency range;
- and
- responsive to a difference between the determined resonant frequency and a baseline resonant frequency of the lens, selectively provide the drive signal at the driver output for causing the transducer to vibrate the lens in a lens cleaning operation.
A lens cleaning system, comprising:
- a lens;
- a transducer mechanically coupled to the lens;
- a driver having a driver output coupled to the transducer, the driver including:
- a feedback circuit having a feedback input and a feedback output, the feedback input coupled to the driver output, and the feedback circuit configured to provide a feedback signal at the feedback output responsive to the feedback input, the feedback signal representing an electrical property of the transducer;
- and
- a controller coupled between the feedback output and the driver output, the controller configured to:
- provide an oscillating drive signal at the driver output for causing the transducer to vibrate the lens at frequencies within a frequency range;
- responsive to the feedback signal, determine a resonant frequency of the lens within the frequency range;
- and
- responsive to a difference between the determined resonant frequency and a baseline resonant frequency of the lens, selectively provide the drive signal at the driver output for causing the transducer to vibrate the lens in a lens cleaning operation.
Dependencies are inferred from the claim text.