Coretronic Corporation

Yu-Chun Chen

I-Ming Liu

Jui-Ta Liu

Chih-Hsiang Li

The disclosure provides a method and a projection device for focal length calibration. The projection device includes a distance sensor, a projection lens, and a controller. The method includes: defining, by the distance sensor, a detection area on a projection surface; dividing, by the controller, the detection area into a plurality of reference areas; detecting, by the distance sensor, a reference distance between the projection device and each reference area; finding, by the controller, at least one first area and at least one second area in the reference areas; and performing, by the controller, a focusing operation of the projection lens only based on the reference distance of each second area.

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Hsin-Chu, Taiwan

Yu-Chun Chen