The present disclosure provides a method for dynamically adjusting a maximum setting magnification of an optical lens, and this method includes steps as follows. The object distance is detected; the maximum setting magnification of the zoom lens is adjusted according to the object distance; after the object distance is changed, the object distance is detected to determine the focus mode.

A projector includes a light source, a light modulator that modulates light outputted from the light source, a projection system that projects the light modulated by the light modulator, an image sensor that acquires information on an image projected by the projection system, an enclosure that accommodates the light source, the light modulator, and the image sensor, and a sensor holder that holds the image sensor. The projection system includes a lens barrel which accommodates a lens and through which the light modulated by the light modulator passes. The lens barrel is held by the enclosure via a lens barrel holder. The sensor holder is held by the lens barrel holder.

An image projection device, such as a pico projector or LCD projector, includes image projection circuitry configured to generate a light beam having a power. The image projection circuitry projects the light beam onto and focuses the light beam on a projection surface located an imaging distance from the image projection circuitry. A time-of-flight sensor is configured to sense the imaging distance between the image projection circuitry and the projection surface and to generate an imaging distance signal indicating the sensed imaging distance. Control circuitry is coupled to the image projection circuitry and to the time-of-flight sensor and is configured to adjust the power and the focus of the light beam based upon the imaging distance signal.

An image projection device, such as a pico projector or LCD projector, includes image projection circuitry configured to generate a light beam having a power. The image projection circuitry projects the light beam onto and focuses the light beam on a projection surface located an imaging distance from the image projection circuitry. A time-of-flight sensor is configured to sense the imaging distance between the image projection circuitry and the projection surface and to generate an imaging distance signal indicating the sensed imaging distance. Control circuitry is coupled to the image projection circuitry and to the time-of-flight sensor and is configured to adjust the power and the focus of the light beam based upon the imaging distance signal.

An electronic apparatus, comprises a projection unit configured to project an image, a measurement unit configured to measure a distance to an object, a projection control unit configured to control, based on the distance to the object measured by the measurement unit, projection of the image by the projection unit so that the image projected onto the object has a preliminarily set actual size length.

An electronic apparatus, comprises a projection unit configured to project an image, a measurement unit configured to measure a distance to an object, a projection control unit configured to control, based on the distance to the object measured by the measurement unit, projection of the image by the projection unit so that the image projected onto the object has a preliminarily set actual size length.

A projection apparatus is provided. A gear structure and a positioning piece in the projection lens module are disposed about opposite sides outside the lens barrel. The gear structure and the positioning piece rotates around an optical axis of the lens barrel acting as a rotating axis. Moreover, when the gear structure rotates, the positioning piece rotates relative to the gear structure. A transmission gear of the motor module meshes with the gear structure to drive the gear structure to rotate. The positioning module is disposed next to the positioning piece and is configured for measuring rotation of the positioning piece to generate a positioning signal. The controller controls the motor module to drive the transmission gear, receives the positioning signal, and calculates a backlash between the transmission gear and the gear structure according to the positioning signal. A backlash detecting system and a method thereof are provided.

A projection apparatus is provided. A gear structure and a positioning piece in the projection lens module are disposed about opposite sides outside the lens barrel. The gear structure and the positioning piece rotates around an optical axis of the lens barrel acting as a rotating axis. Moreover, when the gear structure rotates, the positioning piece rotates relative to the gear structure. A transmission gear of the motor module meshes with the gear structure to drive the gear structure to rotate. The positioning module is disposed next to the positioning piece and is configured for measuring rotation of the positioning piece to generate a positioning signal. The controller controls the motor module to drive the transmission gear, receives the positioning signal, and calculates a backlash between the transmission gear and the gear structure according to the positioning signal. A backlash detecting system and a method thereof are provided.

A projection device and an auto-focus method thereof are provided. The projection device includes a storage device, an image determining circuit, and an auto-focus circuit. The storage device is configured to temporarily store at least two image signals of image data in different time sequences. The image determining circuit is electrically connected to the storage device and is configured to access the image signals to determine whether a target image signal of the image signals meets an auto-focus condition, wherein the auto-focus condition includes the image determining circuit comparing the image signals to determine whether the target image signal is a static image, so as to correspondingly output a focusing signal. The auto-focus circuit is electrically connected to the image determining circuit and is configured to perform, according to the focusing signal, an auto-focus operation on an image projected by the projection device.

The present disclosure relates to the technical field of digital projection and display, and in particular, relates to a method for controlling a focusing assembly. The focusing assembly includes a lens module, a motor, a bevel retaining piece, and a photoelectric switch. The photoelectric switch includes an optical transmitter and an optical receiver that are oppositely disposed, the motor is connected to the lens module. The method includes: receiving a current voltage signal from the photoelectric switch; determining a current position of the lens module based on the current voltage signal; controlling the motor to stop driving the lens module in response to the current position of the lens module being the predetermined position.