US 12,352,940 B2
Optical system
Satoshi Kuzuhara, Osaka (JP); and Tsuneo Uchida, Chiba (JP)
Assigned to PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD., Osaka (JP)
Filed by Panasonic Intellectual Property Management Co., Ltd., Osaka (JP)
Filed on Aug. 17, 2021, as Appl. No. 17/404,468.
Application 17/404,468 is a continuation of application No. PCT/JP2020/016169, filed on Apr. 10, 2020.
Claims priority of application No. 2019-076468 (JP), filed on Apr. 12, 2019.
Prior Publication US 2021/0373305 A1, Dec. 2, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. G02B 5/04 (2006.01); G02B 17/00 (2006.01); G02B 17/08 (2006.01); G02B 26/10 (2006.01); G02B 27/00 (2006.01)
CPC G02B 17/0856 (2013.01) [G02B 5/04 (2013.01); G02B 17/004 (2013.01); G02B 26/105 (2013.01); G02B 27/0025 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An optical system comprising:
a prism having an incident surface, an exit surface, and one or more reflecting surfaces;
a laser element configured to emit a laser light,
a first scanning element configured to scan the laser light emitted by the laser element in a first direction and emit to the incident surface of the prism,
a second scanning element disposed at a position where the laser light scanned by the first scanning element is emitted from the exit surface of the prism and concentrated, and configured to scan the laser light incident from the exit surface of the prism in the second direction,
wherein
a long diameter direction of a pupil diameter of the laser light emitted from the laser element corresponds to the first direction of the first scanning element,
a short diameter direction of the pupil diameter of the laser light emitted from the laser element corresponds to the second direction of the second scanning element,
the long diameter direction and the short diameter direction are orthogonal to each other,
the reflecting surfaces have different curvatures depending on a scanning direction of the first and the second scanning elements so that the pupil diameter of the laser light in the second direction approaches the pupil diameter in the first direction at the exit surface,
an optical magnification of the prism in the second direction is larger than an optical magnification of the prism in the first direction,
a first intermediate imaging position where a first direction component of the light flux of the laser light forms a first intermediate image in the prism is located closer to the exit surface than a second intermediate imaging position where a second direction component of the light flux of the laser light forms a second intermediate image in the prism,
a focal length of the prism with respect to the second direction component of the light flux of the laser light that forms the second intermediate image in the prism is longer than a focal length of the prism with respect to the first direction component of the light flux of the laser light that forms the first intermediate image in the prism, so that the first intermediate image is not formed at the second intermediate imaging position and the second intermediate image is not formed at the first intermediate imaging position.