US 12,114,833 B2
Optical system, endoscope, and medical image processing system
Koji Kashima, Tokyo (JP); Takeshi Miyai, Tokyo (JP); and Junichiro Enoki, Tokyo (JP)
Assigned to SONY GROUP CORPORATION, Tokyo (JP)
Appl. No. 17/440,217
Filed by SONY GROUP CORPORATION, Tokyo (JP)
PCT Filed Mar. 16, 2020, PCT No. PCT/JP2020/011448
§ 371(c)(1), (2) Date Sep. 17, 2021,
PCT Pub. No. WO2020/196027, PCT Pub. Date Oct. 1, 2020.
Claims priority of application No. 2019-063267 (JP), filed on Mar. 28, 2019.
Prior Publication US 2022/0142458 A1, May 12, 2022
Int. Cl. H04N 23/56 (2023.01); A61B 1/00 (2006.01); A61B 1/04 (2006.01); A61B 1/045 (2006.01); G02B 5/30 (2006.01); G02B 23/24 (2006.01); A61B 1/06 (2006.01); A61B 1/07 (2006.01); H04N 23/50 (2023.01)
CPC A61B 1/000095 (2022.02) [A61B 1/042 (2013.01); A61B 1/045 (2013.01); G02B 5/3083 (2013.01); G02B 23/2484 (2013.01); H04N 23/56 (2023.01); A61B 1/0669 (2013.01); A61B 1/07 (2013.01); H04N 23/555 (2023.01)] 9 Claims
OG exemplary drawing
 
1. An optical system, comprising:
at least two optical elements having an effect of extending a depth of field, wherein
the at least two optical elements include a fixed first birefringent mask and a rotatable second birefringent mask,
the rotatable second birefringent mask is rotatable about an optical axis of the optical system,
the fixed first birefringent mask includes first polarizing elements and first non-polarizing elements,
the rotatable second birefringent mask includes second polarizing elements and second non-polarizing elements,
the fixed first birefringent mask is divided in a form of a first cross at a center of the fixed first birefringent mask to have first four fan shapes so that
a first upper left fan shape of the first four fan shapes and a second lower right fan shape of the first four fan shapes are the first polarizing elements, and
a first upper right fan shape of the first four fan shapes and a second lower left fan shape of the first four fan shapes are the first non-polarizing elements,
the rotatable second birefringent mask is divided in a form of a second cross at a center of the rotatable second birefringent mask to have second four fan shapes so that
a second upper right fan shape of the second four fan shapes and a third lower left fan shape of the second four fan shapes are the second polarizing elements, and
a second upper left fan shape of the second four fan shapes and a third lower right fan shape of the second four fan shapes are the second non-polarizing elements,
the first polarizing elements are concentric from a vicinity of the center of the fixed first birefringent mask toward an outside of the fixed first birefringent mask,
the second polarizing elements are concentric from a vicinity of the center of the rotatable second birefringent mask toward an outside of the rotatable second birefringent mask,
the rotatable second birefringent mask is rotated by 90 degrees with respect to the fixed first birefringent mask,
a polarization direction of the second polarizing elements is at 90 degrees relative to a polarization direction of the first polarization elements after the rotation, and
the effect of extending the depth of field is adjustable based on the rotation of the rotatable second birefringent mask.