Methods and apparatus for ultrasonic lens cleaner using configurable filter banks

Patent metadata

Field	Value
Publication number	US-10384239-B2
Application number	US-201715492315-A
Country	US
Kind code	B2
Filing date	Apr 20, 2017
Priority date	Sep 27, 2016
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

Methods and apparatus for ultrasonic lens cleaner using configurable filter banks are disclosed. In certain described examples, the methods and apparatus can expel fluid from a droplet on an optical surface using an ultrasonic transducer mechanically coupled to the optical surface and having first and second resonant frequency bands.

First claim

What is claimed is:

1. An apparatus, comprising:
an amplifier having an amplifier output, the amplifier output having an amplifier impedance; and
a filter having a filter input and a filter output, the filter input coupled to the amplifier output, the filter output adapted to be coupled to an ultrasonic transducer, the ultrasonic transducer having a transducer impedance and mechanically coupled to a surface, the filter tunable within resonant frequency bands of the surface, and the filter configured to facilitate matching of the amplifier impedance with the transducer impedance to reduce a droplet on the surface by atomization.

2. The apparatus of claim 1 , wherein the filter includes: a first filter tunable within a first resonant frequency band of the surface; and a second filter tunable within a second resonant frequency band of the surface.

3. An apparatus, comprising:
an amplifier having an amplifier output, the amplifier output having an amplifier impedance;
a first filter having a first filter input and a first filter output, the first filter input coupled to the amplifier output, the first filter output adapted to be coupled to an ultrasonic transducer, the ultrasonic transducer having a transducer impedance and mechanically coupled to a surface, the first filter tunable within a first resonant frequency band of the surface, and the first filter configured to facilitate matching of the amplifier impedance with the transducer impedance to reduce by atomization a droplet on the surface from a first droplet size to a second droplet size in a first expelling mode; and
a second filter having a second filter input and a second filter output, the second filter input coupled to the amplifier output, the second filter output adapted to be coupled to the ultrasonic transducer, the second filter tunable within a second resonant frequency band of the surface, and the second filter configured to facilitate matching of the amplifier impedance with the transducer impedance to reduce by atomization the droplet from the second droplet size to a third droplet size in a second expelling mode.

4. The apparatus of claim 3 , wherein the first resonant frequency band is higher in frequency than the second resonant frequency band.

5. The apparatus of claim 3 , wherein the amplifier has an amplifier input, and the apparatus further comprises a controller having a controller output coupled to the amplifier input.

6. The apparatus of claim 5 , wherein the controller is configured to cause: the first filter to generate a first signal at the first filter output, the first signal having a first frequency within the first resonant frequency band; and the second filter to generate a second signal at the second filter output, the second signal having a second frequency within the second resonant frequency band.

7. The apparatus of claim 3 , further comprising the filter switching circuitry coupled between the controller and the first filter, the filter switching circuitry configured to activate the first filter in response to a control signal from the circuitry controller.

8. The apparatus of claim 7 , wherein the control signal is a first control signal, and the filter switching circuitry is coupled between the controller and the second filter, the filter switching circuitry configured to activate the second filter in response to a second control signal from the controller.

9. The apparatus of claim 3 , further comprising filter switching circuitry, the filter switching circuitry including:
an ultrasonic transducer coupler;
a high side switch coupled between the first filter and the a first ultrasonic transducer coupler; and
a filter switch controller coupled to the high side switch, the filter switch controller configured to control the high side switch in a first high side switch state when the first filter is to be activated for coupling with the ultrasonic transducer coupler, and to control the first high side switch in a second high side switch state when the first filter is to be deactivated from coupling with the ultrasonic transducer coupler.

10. The apparatus of claim 9 , wherein the filter switching circuitry includes:
a low side switch coupled between the first filter and a ground reference; and
the filter switch controller is coupled to the low side switch, and the filter switch controller is configured to control the low side switch in a first low side switch state when the first filter is to be activated, and to control the low side switch in a second low side switch state when the first filter is to be deactivated.

11. The apparatus of claim 10 , wherein the ultrasonic transducer coupler is a first ultrasonic transducer coupler, the high side switch is a first high side switch, and the filter switching circuitry includes:
a second ultrasonic transducer coupler; and
a second high side switch coupled between the second filter and the second ultrasonic transducer coupler; and
the filter switch controller is coupled to the second high side switch, and the filter switch controller is configured to control the second high side switch in the first high side switch state when the second filter is to be activated for coupling with the second ultrasonic transducer coupler, and to control the second high side switch in the second high side switch state when the second filter is to be deactivated from coupling with the second ultrasonic transducer coupler.

12. The apparatus of claim 11 , wherein the filter switching circuitry includes:
a second low side switch coupled between the second filter and the ground reference; and
the filter switch controller is coupled to the second low side switch, and the filter switch controller is configured to control the second low side switch in the first low side switch state when the second filter is to be activated, and to control the second low side switch in the second low side switch state when the second filter is to be deactivated.

13. The apparatus of claim 3 , wherein the amplifier is a first amplifier, and the apparatus further comprises a second amplifier and a pair of ultrasonic transducer couplers, the pair of ultrasonic transducer couplers configured to couple a bridge tied load including the ultrasonic transducer between the first amplifier and the second amplifier.

14. The apparatus of claim 3 , wherein the first filter is a first filter network, and the apparatus includes a second filter network and a pair of ultrasonic transducer couplers, the pair of ultrasonic transducer couplers configured to couple a bridge tied load including the ultrasonic transducer between the first filter network and the second filter network.

15. The apparatus of claim 14 , wherein the pair of ultrasonic transducer couplers is coupled between the first filter network and the second filter network in a balanced filter including the first filter network and the second filter network.

16. The apparatus of claim 15 , wherein:
the first filter network has a first filter network quality factor;
the balanced filter has a balanced filter quality factor; and
the balanced filter quality factor is greater than the first filter network quality factor.

17. A method, comprising:
activating a filter tuned within a resonant frequency band of an ultrasonic transducer to facilitate matching an output impedance of an amplifier with an impedance of the ultrasonic transducer, the ultrasonic transducer mechanically coupled to a surface;
generating a signal including a frequency within the resonant frequency band of the ultrasonic transducer; and
reducing by atomization a dr

Assignees

• Texas Instruments Inc

Inventors

• Fedigan Stephen John
• Magee David Patrick

Classifications

• B60S1/02

  Cleaning windscreens, windows or optical devices {(wind deflectors specially adapted for preventing soiling of windows or windscreens B60J1/2002)} · CPC title

• B08B7/028 Primary

  Using ultrasounds · CPC title

• B06B1/0284

  with consecutive, i.e. sequential generation, e.g. with frequency sweep · CPC title

• B60S1/56

  specially adapted for cleaning other parts or devices than front windows or windscreens {(rear-view mirror arrangements mounted on vehicle exterior including cleaning devices B60R1/0602)} · CPC title

• B06B1/023

  and stepped in amplitude, e.g. square wave, 2-level signal · CPC title