Methods of driving a scanning beam device to achieve high frame rates

• US 7,784,697 B2
• Filed: 01/03/2008
• Issued: 08/31/2010
• Est. Priority Date: 12/23/2004
• Status: Active Grant

• Current Assignee: University of Washington
• Original Assignee: University of Washington
• Inventors: Johnston, Richard S, Kundrat, Matthew J, Reinhall, Per G
• Primary Examiner(s): Walsh; Daniel
• Assistant Examiner(s): KIM, TAE W
• Application Number:
  US11/969,141
• Publication Number:
  US 20080218824A1
• Time in Patent Office: 971 Days
• Field of Search: 235/462.32
• US Class Current: 235/462.32
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: G02B 26/105 with one or more pivoting mirrors or galvano-mirrors G02B26/101 takes precedence
• CPC Class Codes: G02B 26/127 Adaptive control of the scanning light beam, e.g. using the feedback from one or more detectors G02B27/0031 takes precedence
• CPC Class Codes: H04N 3/08 having a moving reflector

Abstract

The present invention provides methods and systems for scanning an illumination spot over a target area. The present invention removes stored energy from a scanning element to stop the scanning element from vibrating and to substantially return the scanning element to its starting position so as to enable high frame rates.

Claims

1. A method of driving a scanning beam device that comprises an optical fiber scanning element, the method comprising:

providing the scanning element in a first position;

driving the scanning element, at a frequency within a Q-factor of the scanning element'"'"'s resonant frequency, with a first component of a drive signal to scan an illumination spot in a scan pattern over a target; and

driving the scanning element with a second component of the drive signal to remove stored energy from the scanning element so as to cause the scanning element to substantially return to the first position, the second component comprising a frequency that corresponds to a natural frequency of the scanning element.

2. The method of claim 1, wherein the second component comprises at least two different frequencies.

3. The method of claim 2, wherein the at least two frequencies substantially correspond with the scanning element'"'"'s movement frequency at two or more different times during application of the second component.

4. The method of claim 2, wherein the second component comprises a plurality of frequencies with each frequency substantially corresponding with different movement frequencies of the scanning element during energy removal.

5. The method of claim 1, wherein the second component comprises a first-axis signal and a second-axis signal, where at least one point in time exists where the frequency of the first-axis signal is different than the frequency of the second-axis signal.

6. A scanning beam system comprising:

a scanning beam device comprising an optical fiber scanning element coupled to a drive assembly; and

a base station coupleable to the drive assembly of the scanning beam device, the base station being adapted to deliver a drive signal to the drive assembly to drive the scanning element,

wherein the drive signal comprises;

a first component that is configured to scan an illumination spot emitted from the scanning element from a starting position in a scan pattern and to drive the scanning element at a frequency within a Q-factor of a resonant frequency; and

a second component that is configured to remove stored energy from the scanning element so as to return the scanning element to the starting position, the second component comprising a frequency corresponding to a natural frequency of the scanning element.

7. The system of claim 6, wherein the second component comprises at least two different frequencies.

8. The system of claim 7, wherein the at least two different frequencies substantially correspond with the scanning element'"'"'s movement frequency at two or more different times during application of the second component.

9. The system of claim 7, wherein the second component comprises a plurality of frequencies with each frequency substantially corresponding with different movement frequencies of the scanning element during energy removal.

10. The system of claim 6, wherein the second component comprises a first-axis signal and a second-axis signal, where at least one point in time exists where the frequency of the first-axis signal is different than the frequency of the second-axis signal.