An optical device includes a glass plate, a movable section that supports the glass plate, a shaft section that supports the movable section so as to be swingable around the swing axis, a support section that supports the shaft section, a permanent magnet that is provided in the movable section and is thinner than the glass plate, and a pair of coils that are disposed opposite to each other with the permanent magnet interposed therebetween. The movable section includes thin wall portions that are thinner than the glass plate. The permanent magnet is disposed in the thin wall portions. In side view, the surface of each of the coils on the permanent magnet side is located between both the main surfaces of the glass plate.

A discharge lamp driving device includes a discharge lamp driving unit configured to supply a driving current to a discharge lamp including electrodes, a controller configured to control the discharge lamp driving unit, and a voltage detection unit configured to detect an inter-electrode voltage of the discharge lamp, in which the controller controls the discharge lamp driving unit so that the driving current includes a hybrid period in which a first period for supplying an AC current with a first frequency to the discharge lamp and a second period for supplying a DC current to the discharge lamp are alternately repeated, in which the first frequency includes a plurality of different frequencies, and in which the controller changes the first frequency on the basis of at least one of the detected inter-electrode voltage and driving power supplied to the discharge lamp.

The present disclosure relates to the technical field of digital projection display, and discloses a projection method and a projection apparatus. The method includes: acquiring a target object image; identifying attribute information of a target object based on the target object image; acquiring preset projection content based on the attribute information of the target object; acquiring a projection path; and projecting a projection screen based on the preset projection content and controlling the projection screen to move along the projection path. In this way, the projection is more flexible and more pertinent.

A projector includes a projection section that projects a plurality of patterns having lightness values different from each other, an imaging section that captures an image of the plurality of patterns projected by the projection section, and a projection state adjustment section that adjusts, based on any of the plurality of patterns captured by the imaging section, a projection state in which the projection section performs projection.

Provided are a method and an apparatus for correcting a color convergence error. The method includes: in a dark room environment, collecting a projection light point on a projection screen projected by a projection system, to obtain a projection image; adjusting the test pattern, so that a first projection light point corresponding to the white point of a first coordinate on the test pattern after being projected by a first color light source is located in a center of the projection image; obtaining a second and/or a third projection light points corresponding to the white point of the first coordinate after being projected by a second and/or a third color light sources from the projection image; and adjusting an assembly parameter of the projection system according to a position of the second and/or the third projection light points and a position of the first projection light point.

A projection zoom lens is essentially constituted by, in order from the magnification side: a negative first lens group, which is fixed when changing magnification; a positive second lens group, which moves when changing magnification; a plurality of other lens groups; and a final lens group, which is fixed when changing magnification. The distances among all adjacent lens groups change when changing magnification. The first through third lenses from the magnification side within the first lens group are a first single lens having an aspherical surface with a concave surface toward the magnification side and a negative refractive power in the paraxial region, a second single lens having an aspherical surface, and a third lens. A first lens group front group constituted by the first through third lenses has a negative refractive power. Predetermined conditional formulae are satisfied.

The present disclosure provides a device, in particular a multifocal display device. The device includes: a display element configured to generate an image; and a controller configured to control the display element according to at least a first bit sequence provided over a first determined time period and a second bit sequence provided over a second determined time period, in order to generate the image with one or more colors, the bit sequences including for each color a number of bits of different significance. Moreover, the device is configured to generate the first bit sequence from an original bit sequence based on discarding at least one bit of a color and to generate the second bit sequence from the original bit sequence based on discarding at least one other bit of the color.

An image projection device includes: a light source that emits a laser beam; a control unit that generates an image light beam, and controls emission of the image light beam; a scan unit that scans the image light beam to convert it into scan light; a first light converging unit that is disposed before a user's eye, converges the scan light at a first convergence point near a pupil, and then irradiates the retina with the scan light to project the image on the retina; and a second light converging unit that converges the scan light at a second convergence point before the first light converging unit, and then irradiates the first light converging unit with the scan light; wherein a scan angle of the scan light is substantially the same size as a convergence angle at which the scan light converges to the first convergence point.

An object of the present invention is to provide a projection type image display apparatus in which an imaging lens can be replaced according to a focal length of a projection lens. In order to achieve the above object, a projection type image display apparatus includes: a light source; a lighting optical system configured to guide light from the light source to a display element; a projection lens mounting portion in which a projection lens configured to project the light transmitting through or being reflected by the display element is mountable, and that is configured to allow one replaceable projection lens of a plurality of replaceable projection lenses to be selectively mounted in the projection type image display apparatus; and an imaging lens mounting portion configured to allow one imaging lens of a plurality of replaceable imaging lenses to be selectively mounted in the projection type image display apparatus.

A front projection display device is provided including an image-generating source configured to generate an image, a wide angle lens system adapted to receive the image, and a screen. The wide angle lens system may be configured to increase distortion of the image in a first stage and decrease distortion of the image in a second stage. The screen may be configured to receive the image from the wide angle lens system on a first side and reflect the image back to a viewer on the first side. In another embodiment, a screen is provided for a front projection system, the screen may be configured to receive light from a steep angle and may include any number of surface topographies configured to reflect light back to the viewer along a desired viewing plane.