Optical scanning apparatus, image projecting apparatus, and mobile object

Patent metadata

Field	Value
Publication number	US-10831024-B2
Application number	US-201916299910-A
Country	US
Kind code	B2
Filing date	Mar 12, 2019
Priority date	Mar 16, 2018
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

An optical scanning apparatus, an image projecting apparatus, and a mobile object. The optical scanning apparatus includes a light source to emit light, a light deflector to deflect the light emitted from the light source at least in a sub-scanning direction to perform optical scanning on a scan region, a light receiver to receive, within a predetermined range in the sub-scanning direction, the light used for optical scanning performed by the light deflector, and a controller to control the light deflector based on a number of times of light reception of the light receiver at a plurality of positions in the sub-scanning direction within the predetermined range. The image projecting apparatus includes the optical scanning apparatus, and a projection optical system configured to project light emitted from the optical scanning apparatus to the scan region.

First claim

What is claimed is:

1. An optical scanning apparatus comprising:
a light source configured to emit light;
a light deflector configured to deflect the light emitted from the light source at least in a sub-scanning direction to perform optical scanning on a scan region,
wherein the light deflector includes a micro electromechanical system device,
wherein the micro electromechanical system includes a reflection surface that moves at least either monoaxially or biaxially in a reciprocal manner based on a drive signal from a controller;

a light receiver configured to receive, within a predetermined range in the sub-scanning direction, the light used for optical scanning performed by the light deflector; and
the controller, wherein the controller is configured to
calculate a number of times that the light is received by the light receiver,
compare the number of times that the light is received by the light receiver to a predetermined value, and
adjust the drive signal when the number of times that the light is received by the light receiver is greater than the predetermined value.

2. The optical scanning apparatus according to claim 1 ,
wherein the controller is configured to adjust the drive signal such that the number of times that the light is received by the light receiver is restored to a predetermined number of times if the number of times that the light is received by the light receiver is greater than the predetermined number of times.

3. The optical scanning apparatus according to claim 1 , wherein the light receiver receives, on a single light receiving surface, light emitted to the predetermined range.

4. The optical scanning apparatus according to claim 1 , wherein the light receiver receives, on different light receiving surfaces, light emitted to the predetermined range.

5. The optical scanning apparatus according to claim 1 , wherein the number of times that the light is received by the light receiver comprises a number of times that the light is received by the light receiver during different optical scanning steps on the scan region.

6. The optical scanning apparatus according to claim 1 , wherein the predetermined range comprises positions for which an interval is the largest or smallest when speed of scanning in the sub-scanning direction performed by the light deflector varies.

7. An optical scanning apparatus comprising:
a light source configured to emit light;
a light deflector configured to deflect the light emitted from the light source at least in a sub-scanning direction to perform optical scanning on a scan region,
wherein the light deflector includes a micro electromechanical system device,
wherein the micro electromechanical system includes a reflection surface that moves at least either monoaxially or biaxially in a reciprocal manner based on a drive signal from a controller;

a light receiver configured to receive, within a predetermined range in the sub-scanning direction, the light used for optical scanning performed by the light deflector; and
the controller, wherein the controller is configured to
calculate a time difference between a first time at which the light receiver receives the light at a first position and a second time at which the light receiver receives the light at a second position, the first and second positions being the most distant positions from each other in the sub-scanning direction within the predetermined range,
compare the time difference to a predetermined value, and
adjust the drive signal when the time difference is greater than the predetermined value.

8. The optical scanning apparatus according to claim 7 , wherein the controller is configured to adjust the drive signal such that the time difference is restored to a predetermined time if the time difference is greater than the predetermined time.

9. The optical scanning apparatus according to claim 7 , wherein the light receiver receives, on a single light receiving surface, light emitted to the predetermined range.

10. The optical scanning apparatus according to claim 7 , wherein the light receiver receives, on different light receiving surfaces, light emitted to the predetermined range.

11. The optical scanning apparatus according to claim 7 , wherein the first time and second time comprise times when the light receiver receives the light during different optical scanning steps on the scan region.

12. The optical scanning apparatus according to claim 7 , wherein the predetermined range comprises positions for which an interval is the largest or smallest when speed of scanning in the sub-scanning direction performed by the light deflector varies.

13. An image projecting apparatus comprising:
an optical scanning apparatus including
a light source configured to emit light,
a light deflector configured to deflect the light emitted from the light source at least in a sub-scanning direction to perform optical scanning on a scan region,
wherein the light deflector includes a micro electromechanical system device,
wherein the micro electromechanical system includes a reflection surface that moves at least either monoaxially or biaxally in a reciprocal manner based on a drive signal from a controller,

a light receiver configured to receive, within a predetermined range in the sub-scanning direction, the light used for optical scanning performed by the light deflector, and
the controller, wherein the controller is configured to
calculate a number of times that the light is received by the light receiver,
compare the number of times that the light is received by the light receiver to a predetermined value, and
adjust the drive signal when the number of times that the light is received by the light receiver is greater than the predetermined value; and

a projection optical system configured to project light emitted from the optical scanning apparatus to the scan region,
wherein the light deflector of the optical scanning apparatus scans, with light that is modulated based on image information, the scan region to project an image.

14. A mobile object comprising:
an optical scanning apparatus including a light source configured to emit light, a light deflector configured to deflect the light emitted from the light source at least in a sub-scanning direction to perform optical scanning on a scan region, wherein the light deflector including includes a micro electromechanical system device, wherein the micro electromechanical system includes a reflection surface that moves at least either monoaxially or biaxially in a reciprocal manner based on a drive signal from a controller,
a light receiver configured to receive, within a predetermined range in the sub-scanning direction, the light used for optical scanning performed by the light deflector, and the controller, wherein the controller is configured to calculate a number of times that the light is received by the light receiver, compare the number of times that the light is received by the light receiver to a predetermined value, and adjust the drive signal when the number of times that the light is received by the light receiver is greater than the predetermined value; and a projection optical system configured to project light emitted from the optical scanning apparatus to the scan region, wherein the light deflector of the optical scanning apparatus scans, with light that is modulated based on image information, the scan region to project an image.

Assignees

• Yamashiro Toshihiro
• Hashiguchi Tsuyoshi
• Ricoh Co Ltd

Inventors

• Yamashiro Toshihiro
• Hashiguchi Tsuyoshi

Classifications

• H04N9/3194

  including sensor feedback · CPC title

• H04N1/0443

  Varying the scanning velocity or position · CPC title

• H04N2201/04732

  Detecting at infrequent intervals, e.g. once or twice per line for main-scan control · CPC title

• H04N1/053

  in main scanning direction, e.g. synchronisation of line start or picture elements in a line · CPC title

• H04N2201/0471

  using dedicated detectors · CPC title