Optical deflection device, apparatus including the same, and method of controlling optical deflecting device

Patent metadata

Field	Value
Publication number	US-9291817-B2
Application number	US-201414483393-A
Country	US
Kind code	B2
Filing date	Sep 11, 2014
Priority date	Sep 13, 2013
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

An optical deflecting device includes a mirror having a reflecting surface and a support unit to support the mirror. The support unit includes a first drive unit. The first drive unit includes a plurality of continuously meandering first beams and a plurality of first piezoelectric members respectively provided to the plurality of first beams to swing the mirror around a first axis to deflect light incident on the reflecting surface of the mirror. Two voltages having non-similar waveforms are respectively applied in parallel to each two of the first piezoelectric members respectively provided to adjacent two of the first beams.

First claim

What is claimed is:

1. An optical deflecting device comprising:
a mirror having a reflecting surface; and
a support unit to support the mirror,
wherein the support unit includes a first drive unit including a plurality of continuously meandering first beams and a plurality of first piezoelectric members respectively provided to the plurality of first beams to swing the mirror around a first axis to deflect light incident on the reflecting surface of the mirror, and
wherein two voltages having non-similar waveforms are respectively applied in parallel to each two of the first piezoelectric members respectively provided to adjacent two of the first beams.

2. The optical deflecting device according to claim 1 , wherein the respective waveforms of the two voltages are set to suppress fluctuations in a swing speed of the mirror around the first axis.

3. The optical deflecting device according to claim 1 , wherein one of the two voltages has a sawtooth waveform, and the other one of the two voltages has an inverse sawtooth waveform having a period equal to a period of the sawtooth waveform and shifted in phase from the sawtooth waveform.

4. The optical deflecting device according to claim 1 , wherein the two voltages have different amplitudes.

5. The optical deflecting device according to claim 4 , wherein a ratio between the respective amplitudes of the two voltages and the waveform of one of the two voltages are previously stored, and the waveform of the other one of the two voltages is calculated based on the previously stored ratio between the amplitudes of the two voltages and the previously stored waveform of the one of the two voltages.

6. The optical deflecting device according to claim 4 , further comprising:
a memory configured to store the respective amplitudes of the two voltages; and
a controller configured to calculate the respective waveforms of the two voltages based on the stored amplitudes of the two voltages.

7. The optical deflecting device according to claim 1 , wherein the two voltages have different duty ratios.

8. The optical deflecting device according to claim 7 , wherein a ratio between the respective duty ratios of the two voltages and the waveform of one of the two voltages are previously stored, and the waveform of the other one of the two voltages is calculated based on the previously stored ratio between the duty ratios of the two voltages and the previously stored waveform of the one of the two voltages.

9. The optical deflecting device according to claim 7 , further comprising:
a memory configured to store the respective duty ratios of the two voltages; and
a controller configured to calculate the respective waveforms of the two voltages based on the stored duty ratios of the two voltages.

10. The optical deflecting device according to claim 1 , wherein the support unit further includes a second drive unit connected to the first drive unit to swing the mirror around a second axis perpendicular to the first axis.

11. The optical deflecting device according to claim 10 , wherein the second drive unit includes torsion bars extending in the direction of the second axis and each having a portion connected to the mirror, second beams connected to another portion of each of the torsion bars, and second piezoelectric members provided to the second beams.

12. An apparatus comprising:
a light source device including a light source to emit light modulated based on image information; and
the optical deflecting device according to claim 1 to deflect the light emitted from the light source device to a scanning surface to scan the scanning surface with the light and form an image on the scanning surface.

13. The apparatus according to claim 12 , wherein the scanning surface is a surface of a member that transmits the light deflected by the optical deflecting device.

14. A vehicle comprising:
the apparatus according to claim 12 .

15. A method of controlling an optical deflecting device including a mirror having a reflecting surface and a support unit to support the mirror, the support unit including a first drive unit including a plurality of continuously meandering first beams and a plurality of first piezoelectric members respectively provided to the plurality of first beams to swing the mirror around a first axis to deflect light incident on the reflecting surface of the mirror,
the method comprising applying, in parallel and respectively, two voltages to each two of the first piezoelectric members respectively provided to adjacent two of the first beams.

16. The method of controlling an optical deflecting device according to claim 15 , wherein the two voltages being applied have non-similar waveforms.

17. The method of controlling an optical deflecting device according to claim 15 , further comprising setting the respective waveforms of the two voltages to suppress fluctuations in a swing speed of the mirror around the first axis.

18. The method of controlling an optical deflecting device according to claim 15 ,
the method further comprising:
adjusting an amplitude or duty ratio of at least one of the two voltages to suppress fluctuations in a swing speed of the mirror around the first axis; and
storing one of the adjusted amplitude or duty ratio and a value in a memory based on the adjusted amplitude or duty ratio.

19. The method of controlling an optical deflecting device according to claim 18 , further comprising:
adjusting a phase difference between the two voltages to suppress the fluctuations in the swing speed of the mirror around the first axis; and
storing the adjusted phase difference in the memory.

Assignees

• Hashiguchi Tsuyoshi
• Kitazawa Tomofumi
• Akanuma Goichi
• Ricoh Co Ltd

Inventors

• Hashiguchi Tsuyoshi
• Kitazawa Tomofumi
• Akanuma Goichi

Classifications

• G02B26/0858

  the reflecting means being moved or deformed by piezoelectric means · CPC title

• G02B26/101

  with both horizontal and vertical deflecting means, e.g. raster or XY scanners (colour television using laser beams scanning a display screen H04N9/3129) · CPC title

• G02B26/105 Primary

  with one or more pivoting mirrors or galvano-mirrors (G02B26/101 takes precedence) · CPC title

• H04N9/3135

  Driving therefor · CPC title