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.

Disclosed is an ultra-short focus projecting optical system, which includes a display unit, a first lens group having a positive focus power, a second lens group having a positive focus power, a third lens group having a negative focus power, and an aspherical reflector arranged sequentially along a projection direction. The first lens group includes a first lens, a second lens and a diaphragm arranged sequentially along the projection direction. The first lens is a glass aspherical lens, the second lens is a glass spherical lens, and the first lens and the second lens are bent toward the diaphragm from their respective centers to their respective peripheries. The ultra-short focus projecting optical system and a projection device provided by this application can realize a large aperture and high resolution.

Disclosed is an ultra-short focus projecting optical system, which includes a display unit, a first lens group having a positive focus power, a second lens group having a positive focus power, a third lens group having a negative focus power, and an aspherical reflector arranged sequentially along a projection direction. The first lens group includes a first lens, a second lens and a diaphragm arranged sequentially along the projection direction. The first lens is a glass aspherical lens, the second lens is a glass spherical lens, and the first lens and the second lens are bent toward the diaphragm from their respective centers to their respective peripheries. The ultra-short focus projecting optical system and a projection device provided by this application can realize a large aperture and high resolution.

A control device of a piezoelectric drive device includes a drive pulse signal generation unit that generates a binary drive pulse signal, a drive signal generation unit that generates a drive signal which is applied to the piezoelectric element for drive from the drive pulse signal, a detection pulse signal generation unit that generates a detection pulse signal by binarizing the detection signal which is output from the piezoelectric element for detection, and a phase difference acquisition unit that acquires a phase difference between the drive pulse signal and the detection pulse signal, based on a rising edge and a falling edge of the drive pulse signal and a rising edge and a falling edge of the detection pulse signal.

A control device of a piezoelectric drive device includes a drive pulse signal generation unit that generates a binary drive pulse signal, a drive signal generation unit that generates a drive signal which is applied to the piezoelectric element for drive from the drive pulse signal, a detection pulse signal generation unit that generates a detection pulse signal by binarizing the detection signal which is output from the piezoelectric element for detection, and a phase difference acquisition unit that acquires a phase difference between the drive pulse signal and the detection pulse signal, based on a rising edge and a falling edge of the drive pulse signal and a rising edge and a falling edge of the detection pulse signal.

Provided is an image presentation system 10, including: a plurality of particle emission units 20 each of which emits particles; an image projection unit 30; and a control unit 50. The control unit 50 controls to cause collision of particles emitted from a first particle emission unit 20 (#1), out of the plurality of particle emission units 20, and particles emitted from a second particle emission unit 20 (#2), out of the plurality of particle emission units, so as to generate a retention field 60 that is used as a screen to which an image is project, and the image projection unit 30 projects an image to the retention field 60.

A search is enabled for an adjustment value with which a good blur correction effect is obtained by blur correction processing as an optical adjustment value of an image projection device, and blur correction performance is improved in a case where correction of a focus blur that occurs in a projection image is performed by signal processing. An image processing device according to the present technology includes: a blur correction unit that performs blur correction processing for focus blur correction on an input image on the basis of a blur characteristic that is a characteristic of a focus blur that occurs in a projection image of an image projection device, the blur characteristic being measured in a state where a predetermined candidate value is set as an optical adjustment value of the image projection device; and a use determination unit that performs evaluation regarding the focus blur on a projection image obtained by causing the image projection device to project an image subjected to the blur correction processing, and performs determination regarding whether or not the candidate value is usable on the basis of a result of the evaluation.

An autofocus projection apparatus having focal-length fine adjustment is disclosed. A projection light engine including the same is also disclosed. The autofocus projection apparatus comprises a projection lens system, which comprises a first lens group, a second lens group, an aperture stop, a third lens group and a forth lens group arranged from a long conjugate side to a short conjugate side; a stepper motor, a control board, and a time-of-flight (TOF) distance measurement module; wherein the stepper motor is connected to an inner barrel for enclosing the second group lens through an adjustment level and only moves the second lens group for autofocus adjustment based on projection distances measured by the TOF distance measurement module. A 3D TOF module which includes a modulated flash light emitter and a CMOS camera sensor, can be used for automatic keystone correction as well as autofocus distance detection in the projection light engine.

An autofocus projection apparatus having focal-length fine adjustment is disclosed. A projection light engine including the same is also disclosed. The autofocus projection apparatus comprises a projection lens system, which comprises a first lens group, a second lens group, an aperture stop, a third lens group and a forth lens group arranged from a long conjugate side to a short conjugate side; a stepper motor, a control board, and a time-of-flight (TOF) distance measurement module; wherein the stepper motor is connected to an inner barrel for enclosing the second group lens through an adjustment level and only moves the second lens group for autofocus adjustment based on projection distances measured by the TOF distance measurement module. A 3D TOF module which includes a modulated flash light emitter and a CMOS camera sensor, can be used for automatic keystone correction as well as autofocus distance detection in the projection light engine.

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.