US 11,940,610 B2
Autofocus system and autofocus method
Chien-Sheng Liu, Tainan (TW); and Ho-Da Tu, Kaohsiung (TW)
Assigned to National Cheng-Kung University, Tainan (TW)
Filed by National Cheng-Kung University, Tainan (TW)
Filed on Dec. 27, 2021, as Appl. No. 17/562,006.
Claims priority of application No. 110146579 (TW), filed on Dec. 13, 2021.
Prior Publication US 2023/0185072 A1, Jun. 15, 2023
Int. Cl. G02B 21/00 (2006.01); G02B 21/02 (2006.01); G02B 21/36 (2006.01); H04N 23/67 (2023.01)
CPC G02B 21/361 (2013.01) [G02B 21/02 (2013.01); H04N 23/67 (2023.01)] 8 Claims
OG exemplary drawing
 
1. An autofocus system, comprising:
a focus light source, configured to emit a focus light beam;
an objective lens, disposed on a transmission path of the focus light beam, wherein the focus light beam irradiates a sample after passing through the objective lens;
a defocus lens, disposed on the transmission path of the focus light beam, so that a minimum light point of the focus light beam passing through the objective lens deviates from a focus of the objective lens;
a first image sensor, configured to receive a focus reflected light beam generated after the focus light beam is reflected by the sample; and
a controller, electrically connected to the first image sensor,
wherein the controller drives the objective lens or the sample to move according to a center change of gravity, a position change, or an energy change of a light spot formed by the focus reflected light beam on an image plane of the first image sensor, so that the focus of the objective lens falls on the sample,
the autofocus system further comprising a second image sensor, configured to receive an image beam generated after an illumination light beam irradiates the sample, wherein after the controller enables the focus of the objective lens to fall on the sample, a minimum light point of a parallel image beam, after passing through the objective lens, is back traced from an image plane of the second image sensor and falls on the sample.