The present invention relates to projection and schlieren optical measurement technology, and more particularly to an integrated projection-schlieren optical system. The system includes a parallel light source system, a first positive lens, a diaphragm, a second positive lens, an image sensor, a negative lens, a knife edge device and a sample stage. In the system, a projection telescopic optical system and a schlieren camera optical system are respectively formed through the combination of optical characteristics of two movable lenses, enabling the integration functions of the projection optical system and the schlieren optical system.

A miniature wide-angle imaging lens has a miniaturization ratio, of a total track length from the center of a first surface to a focal plane by an image circle diameter, with a value less than 3.0. The imaging lens includes, starting from an object side of the lens, a first group of at least three optical elements, a second group including an aperture stop and an optical element immediately in front of or behind the aperture stop, and a third group of at least two optical elements.

In an optical system, a height from an optical axis of a paraxial marginal ray that passes through a lens surface closest to an object is smaller than a maximum height from the optical axis of the paraxial marginal ray that passes through a lens surface on an image side of an intersection between the optical axis and a paraxial chief ray. The optical system includes an optical element disposed on an object side or the image side of the intersection. The optical element has positive refractive power in a case where the optical element is disposed on the object side of the intersection, and has negative refractive power in a case where the optical element is disposed placed on the image side of the intersection. A predetermined condition is satisfied.

In an optical system, a height from an optical axis of a paraxial marginal ray that passes through a lens surface closest to an object is smaller than a maximum height from the optical axis of the paraxial marginal ray that passes through a lens surface on an image side of an intersection between the optical axis and a paraxial chief ray. The optical system includes an optical element disposed on an object side or the image side of the intersection. The optical element has positive refractive power in a case where the optical element is disposed on the object side of the intersection, and has negative refractive power in a case where the optical element is disposed placed on the image side of the intersection. A predetermined condition is satisfied.

Provided is a zoom lens, which includes lens units, in which an interval between each pair of adjacent lens units is changed during zooming, the zoom lens including, in order from an object side to an image side: a first lens unit having a negative refractive power; a first lens subunit having a positive refractive power; and a second lens subunit having a negative refractive power. During focusing from infinity to minimum object distance, the first lens subunit is moved toward the object side, and the second lens subunit is moved toward the image side. Further, a movement amount of the first lens subunit during focusing from infinity to minimum object distance at a telephoto end, a movement amount of the second lens subunit during focusing from infinity to minimum object distance at the telephoto end, and a focal length at the telephoto end are appropriately set.

An optical projector comprises a collimated light source, a pattern generating optical element, and a variable optical element positioned optically between the collimated light source and the pattern generating optical element. The variable optical element is configured to adjust a divergence of a light beam incident on the pattern generating optical element. The pattern generating optical element is configured to emit patterned light when the variable optical element is in a first state, and to emit non-patterned light when the variable optical element is in a second state.

An annular optical element includes a first side surface, a second side surface, an outer annular surface and an inner annular surface. The outer annular surface connects the first side surface and the second side surface, and surrounds a central axis of the annular optical element. The inner annular surface connects the first side surface and the second side surface, surrounds the central axis, and is closer to the central axis than the outer annular surface is to the central axis. The inner annular surface includes a plurality of protrusion circles surrounding the central axis and arranged along a direction from the first side surface towards the second side surface. Each of the protrusion circles includes a plurality of protrusion structures and a plurality of separation structures, and the protrusion structures and the separation structures are alternately arranged to surround the central axis.

An imaging lens set includes three plastic lens elements, which are a first lens element, a second lens element and a third lens element, and a light blocking sheet. The first lens element includes a first flat abutting portion and a first conical surface. The second lens element includes a second flat abutting portion, a second conical surface, a fourth flat abutting portion and a fourth conical surface. The third lens element includes a third flat abutting portion and a third conical surface. The first flat abutting portion is abutted with the second flat abutting portion, the first conical surface contacts with the second conical surface, and the third conical surface contacts with the fourth conical surface. The light blocking sheet is abutted with the third flat abutting portion and the fourth flat abutting portion, respectively.

An optical lens assembly includes: a first element group, including a first lens group, a partial-reflective-partial-transmissive element and a first optical layer that is located on a visual-side surface of a lens of the first lens group closest to a visual side and includes, in order from the visual side to an image source side, a first absorptive polarizer, a reflective polarizer and a first phase retarder; a second element group, including a second lens group and an image source plane; and a second optical layer, located between the partial-reflective-partial-transmissive element and the image source plane and including, in order from the visual side to the image source side, a second phase retarder and a second absorptive polarizer. When the optical lens assembly satisfies a specific condition, the weight of the device can be reduced, the zoom function can be provided, and the image quality can be ensured.

An optical lens assembly includes: a first element group, including a first lens group, a partial-reflective-partial-transmissive element and a first optical layer that is located on a visual-side surface of a lens of the first lens group closest to a visual side and includes, in order from the visual side to an image source side, a first absorptive polarizer, a reflective polarizer and a first phase retarder; a second element group, including a second lens group and an image source plane; and a second optical layer, located between the partial-reflective-partial-transmissive element and the image source plane and including, in order from the visual side to the image source side, a second phase retarder and a second absorptive polarizer. When the optical lens assembly satisfies a specific condition, the weight of the device can be reduced, the zoom function can be provided, and the image quality can be ensured.