Abstract: An imaging lens includes a first lens group and a second lens group. The first lens group includes three lenses with refractive powers, where two of three lenses of the first lens group are aspheric lenses. The second lens group includes three lenses with refractive powers, where one of three lenses is an aspheric lens and other two lenses are paired to form a doublet lens. The imaging lens satisfies conditions of 3.0<LT/IMH<3.5 and 1.0<D1/LT<1.08, where IMH is a semi-diagonal image height of the imaging lens, D1 is a lens diameter of a lens closest to an object side of the imaging lens, and LT is a distance measured along an optical axis between two outermost lens surfaces with refractive powers at opposite ends of the imaging lens.

Abstract: A vehicle projection lens includes an aspheric first lens, a cemented lens consisting of a spherical second lens and a spherical third lens, and a spherical fourth lens in order from a magnified side to a minified side. An F-number of the vehicle projection lens is smaller than or equal to 0.86, a field of view of the vehicle projection lens is greater than 14 degrees and smaller than 44 degrees, and the vehicle projection lens consists essentially of four lenses respectively with positive, negative, positive and positive refractive powers.

Abstract: An imaging lens including a first lens group, a second lens group, and an aperture stop disposed between the first lens group and the second lens group is provided. The first lens group includes at least one and at most three lenses with refractive powers, and the second lens group has a positive refractive power and includes at least two and at most three lenses with a refractive powers. The imaging lens satisfies conditions of 2 mm<LT<20 mm and 0.8<D1/LT<1.4, where D1 is a lens diameter of the lens closest to the object side, and LT is distance along the optical axis between two outermost lens surfaces at opposite ends of the first lens group and the second lens group.

Abstract: A 3D printing apparatus including a base plate, a transparent plate, a fluid space, a molding container, a heater, a fluid guider and a light engine is provided. The fluid space is disposed between the base plate and the transparent plate. The molding container has an accommodating space and the base plate is disposed in the accommodating space. The heater is configured to heat a fluid. The fluid guider is configured to guide the heated fluid into the fluid space. The light engine is configured to project a pixelated light on the base plate.

Abstract: An optical lens includes an aperture, a first lens, a second lens, a third lens, and a fourth lens sequentially in a direction. One of the first lens and the second lens has positive refracting power, and the other has negative refracting power. The third lens has refracting power, and is a lens with a largest diameter in the optical lens. The fourth lens has the refracting power. The four lenses are made of glass. For light having a wavelength of 1315 nm, a transmittance of the optical lens is greater than ninety percent.

Abstract: An imaging lens including an aperture stop, a first lens, a second lens and a third lens sequentially arranged along an optical axis from an object side to an image side is provided. The first lens is an aspheric glass lens and has positive refracting power. The second lens is an aspheric plastic lens. The third lens is an aspheric plastic lens. The imaging lens has the transmittance higher than 85% for light with a wavelength of 940 nm and has the field of view less than 90 degrees.

Abstract: A fixed-focus lens includes an anti-radiation first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in order in a direction. An aperture stop is disposed between the first lens and the fourth lens. A ratio of a lens diameter of the first lens to an overall length is within a range of 0.4 to 0.5, where the overall length is an axial distance between an outer surface of the first lens and an outer surface of the seventh lens. Each of the first lens to the seventh lens is a spherical glass lens.

Abstract: An optical lens includes a first lens, a second lens, a third lens, a fourth lens and a cemented lens. The first lens is closest to a magnified side as compared with any other lens of the optical lens, one of the second lens and the third lens is a first aspheric lens, and the fourth lens is a second aspheric lens and disposed between the cemented lens and a minified side of the optical lens. The optical lens satisfies the condition: 1.0<D1/DL<4.0, where D1 denotes a lens diameter of the first lens and DL denotes a lens diameter of the fourth lens.

Abstract: A de-speckle device includes an optical homogenizer, a connecting mechanism, and an actuator. The optical homogenizer includes a diffuse surface and a reflecting surface disposed opposite to the diffuse surface. One end of the connecting mechanism is connected to the optical homogenizer. The actuator can move the optical homogenizer back and forth along an axis of the optical homogenizer.

Abstract: A de-speckle mechanism includes a carrier, an optical homogenizer, an outer frame, a first flexible component, and a first actuator. The optical homogenizer is provided with a light-receiving surface and is disposed on the carrier. The outer frame is disposed adjacent to the carrier. The first flexible component is the only component connecting the carrier and the outer frame. The first actuator includes a first part and a second part which act relative to each other, and the first part is disposed on the carrier. The first actuator can drive the optical homogenizer, with the connecting position between the first flexible component and the outer frame as the fulcrum, so that the optical homogenizer can swing in a plane direction substantially parallel to or identical to the light-receiving surface of the optical homogenizer.

Abstract: A 3D printing apparatus including a tank, a print platform, a motor, a force sensor, and a controller is provided. The tank is configured to accommodate a photocurable resin. The print platform is arranged adjacent to the tank. The motor is mechanically connected to the print platform. The motor is configured to drive the print platform to move. The force sensor includes a position encoder. The controller is electrically connected to the force sensor and the motor. The controller is configured to confirm whether the print platform is configured to reach a target position through a value of the position encoder.

Abstract: A light valve angle dynamic adjustment device for a projector includes a light valve, a first movable portion, a first motor and a first mechanism. The light valve is arranged on a support of the first movable portion. The first motor is capable of driving the first mechanism. The first movable portion is also provided with a first rotation axis and a first mating portion. The first motor is capable of driving the first mechanism to make the first movable portion swing around the first rotation axis through the first mating portion.

Abstract: A lens of a head-mounted display including a see-through mirror/coating, a gradient-index lens element, and a polarizer which are disposed in sequence is provided. The lens also includes a first aspheric lens element disposed between the see-through mirror/coating and the polarizer. The gradient-index lens element has a planar surface, and the quarter-wave plate is disposed on the planar surface of the gradient-index lens element.

Abstract: A lens of a head-mounted display including a see-through mirror/coating, a gradient-index lens element, and a polarizer which are disposed in sequence is provided. The lens also includes a first aspheric lens element disposed between the see-through mirror/coating and the polarizer. The gradient-index lens element has a planar surface, and the quarter-wave plate is disposed on the planar surface of the gradient-index lens element.

Abstract: A display system including a display device and a light combining device is provided. The display device includes a first display region and a second display region. The light combining device has a first surface and a second surface opposite to the first surface. The first surface is capable of reflecting a first light beam from the first display region to an observing region for forming a first virtual image. The second surface is capable of reflecting a second light beam from the second display region to the observing region for forming a second virtual image. A curvature of the first surface is different from a curvature of the second surface, and a position of the first virtual image is different from a position of the second virtual image.

Abstract: A fixed focus lens includes a first lens group with a negative refractive power, an aperture stop, and a second lens group with a positive refractive power arranged in order from a first side to a second side. The first lens group has at least two lenses including at least one aspheric lens. The second lens group includes at least five lenses, the at least five lenses comprising a first compound lens and a second compound lens. A difference between a maximum Abbe number and a minimum Abbe number for all lenses of the first compound lens is greater than 50, and a difference between a maximum Abbe number and a minimum Abbe number for all lenses of the second compound lens is greater than 45.

Abstract: A lens shift backlash elimination device includes a base, a transmission mechanism, and a lens. The transmission mechanism is disposed on the base and includes a first element, a second element, and an elastic element. The second element is mechanically connected to the first element. The elastic element is disposed between the first element and the second element, or abutted against the first element. The lens is mechanically connected to the transmission mechanism. The lens may be displaced relative to the base in a first direction.

Abstract: A three-dimensional printing apparatus includes a liquid tank capable of accommodating a photosensitive liquid. The liquid tank includes a film, a plurality of side walls, a plate and a motor. The film has a workpiece curing area. The plurality of side walls surrounds the film. The plate is capable of supporting the film and having at least one fluid tunnel extending from a first surface of the plate contacting the film to a second surface of the plate. The motor is connected to the liquid tank to incline the liquid tank. A gap is formed between the plat and one of the plurality of side walls of the liquid tank, and the film is communicated with an outside space via the gap.

Abstract: A light path adjustment mechanism includes a support, a carrier, an optical plate member and a plurality of actuators. The carrier is disposed on the support and connected to the support via a first elastic member and a second elastic member. The carrier includes a first side, a second side opposite the first side, a third side and a fourth side opposite the third side, and each of the third side and the fourth side is located between the first side and the second side. The actuators are disposed on at most three sides of the first side, the second side, the third side and the fourth side, and the actuators are disposed at least on the first side and the third side.

Abstract: A zoom lens arranged along an optical axis includes a first lens group and a second lens group. The second lens group has at least one aspheric lens. The first lens group moves toward an image side and the second lens group moves away from the image side along the optical axis during zooming. The first lens group is moved for focusing, and the second lens group is moved for zooming.