Optical deflector, image displaying apparatus, and object apparatus

• US 10,459,218 B2
• Filed: 06/02/2017
• Issued: 10/29/2019
• Est. Priority Date: 12/08/2014
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Suzuki, Shuichi, Hashiguchi, Tsuyoshi, Nakagawa, Jun
• Primary Examiner(s): Deherrera, Kristina M
• Application Number:
  US15/612,259
• Publication Number:
  US 20170269354A1
• Time in Patent Office: 879 Days
• Field of Search: 3592051
• CPC Class Codes: G02B 26/08 for controlling the direction of light in light guides G02B6/35
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 26/12 using multifaceted mirrors
• 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: G02B 27/0018 with means for preventing ghost images anti-reflection coatings G02B1/11
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 5/0231 the surface having microprismatic or micropyramidal shape macroscopic prism arrays G02B5/045
• CPC Class Codes: G02B 5/0294 adapted to provide an additional optical effect, e.g. anti-reflection or filter
• CPC Class Codes: G02B 5/18 Diffraction gratings holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44

Abstract

An optical deflector is used for optically scanning a target surface. The optical deflector includes: a mirror device configured to include a mirror capable of oscillating; and a casing configured to include a window unit for facing the mirror device, and to accommodate the mirror device. The window unit has a transmissive reflection structure in which part of an incident beam is caused to transmit through the window unit toward the mirror, and at least part of a remainder of the incident beam is reflected by the window unit to a direction separated from an optical deflection range that is deflected by the mirror device, and the transmissive reflection structure includes a diffraction grating provided on one of a front surface and a back surface of the window unit.

Claims

1. An optical deflector used for optically scanning a target surface, the optical deflector comprising:

a mirror device configured to include a mirror configured to oscillate; and

a casing configured to include a window unit for facing the mirror device, and to accommodate the mirror device,

wherein the window unit has a transmissive reflection structure in which part of an incident beam is caused to transmit through the window unit toward the mirror, and at least part of a remainder of the incident beam is reflected by the window unit to a direction separated from an optical deflection range that is deflected by the mirror device,

wherein the transmissive reflection structure includes a diffraction grating provided on one of a front surface and a back surface of the window unit, and

wherein the diffraction grating is provided in an area of the window unit through which the part of the incident beam passes, and is not provided in another area of the window unit through which the deflected beam that has been deflected by the mirror device passes.

2. The optical deflector according to claim 1, wherein the transmissive reflection structure further includes a diffraction grating provided on the other one of the front surface and the back surface of the window unit, and

wherein the diffraction gratings respectively provided on the front surface and the back surface have different diffraction angles from each other.

3. The optical deflector according to claim 1,

wherein the transmissive reflection structure further includes a diffraction grating provided on the other one of the front surface and the back surface of the window unit,

wherein antireflection films are respectively provided on the front surface and the back surface, and

wherein the diffraction gratings are respectively provided on the antireflection films.

4. The optical deflector according to claim 1, wherein the diffraction grating has a blazed structure.

5. The optical deflector according to claim 1, wherein the diffraction grating has a binary structure.

6. The optical deflector according to claim 1, wherein the window unit is parallel to a surface on which the mirror device is mounted, in the casing.

7. The optical deflector according to claim 1, wherein an optical path of a reflected beam that has been reflected by the transmissive reflection structure is formed on a side opposite the optical deflection range with respect to an optical path of the incident beam.

8. An image displaying apparatus configured to optically scan a scanned surface, and to display an image, the image displaying apparatus comprising:

an optical source unit configured to emit a beam based on image information; and

the optical deflector of claim 1, configured to deflect the beam emitted from the optical source unit.

9. The image displaying apparatus according to claim 8, further comprising an optical absorber provided in an optical path of a reflected beam that has been reflected by the transmissive reflection structure.

10. The image displaying apparatus according to claim 8, further comprising an optical deflecting unit provided in an optical path of a reflected beam that has been reflected by the transmissive reflection structure.

11. The image displaying apparatus according to claim 10, further comprising an optical absorber provided in an optical path of the reflected beam that has been deflected by the optical deflecting unit.

12. The image displaying apparatus according to claim 8, further comprising an optical system configured to guide the beam that has been formed into the image on the scanned surface to a transmissive reflection member.

13. An object apparatus comprising:

the image displaying apparatus of claim 12; and

an object in which the image displaying apparatus is installed.