Focusing method of optical machine of projector, focusing device and optical machine

A focusing method of an optical machine of a projector,

• comprising steps of:
• attaching a deformation sensor on a light exit surface of a lens of the optical machine to detect a deformation amount of the lens of the optical machine;
• and
• controlling and adjusting a focal length of the lens of the optical machine according to the deformation amount of the lens of the optical machine, wherein
• the step of attaching the deformation sensor on the light exit surface of the lens of the optical machine to detect the deformation amount of the lens of the optical machine comprises:
• detecting, by the deformation sensor, a first deformation amount of the lens of the optical machine as a function of temperature;
• detecting a second deformation amount of the deformation sensor as a function of temperature;
• and
• calculating the deformation amount of the lens of the optical machine according to the first deformation amount and the second deformation amount, wherein the deformation amount of the lens of the optical machine is equal to the first deformation amount minus the second deformation amount, and wherein
• the step of detecting a second deformation amount of the deformation sensor as a function of temperature comprises:
• mounting a temperature sensor on the lens of the optical machine;
• detecting, by the temperature sensor, a temperature change of the deformation sensor;
• and
• determining the second deformation amount of the deformation sensor based on the temperature change.