An alignment checking apparatus holder to assist checking of the alignment of a motor vehicle headlamp installed in a body of a motor vehicle includes a base body, at least one reference marking on the base body, and a multiple of form-fit elements. The base body is visually perceptible from the outside in a checking position. The multiple of form-fit elements are rigidly connected to the base body and are intended to form form-fit connections with parts of the motor vehicle headlamp or of the body of the motor vehicle. The at least one reference marking has a predetermined position with respect to the multiple of form-fit elements.

An alignment checking apparatus holder to assist checking of the alignment of a motor vehicle headlamp installed in a body of a motor vehicle includes a base body, at least one reference marking on the base body, and a multiple of form-fit elements. The base body is visually perceptible from the outside in a checking position. The multiple of form-fit elements are rigidly connected to the base body and are intended to form form-fit connections with parts of the motor vehicle headlamp or of the body of the motor vehicle. The at least one reference marking has a predetermined position with respect to the multiple of form-fit elements.

An optical apparatus includes a folding mirror configured to direct first and second illumination lights on first and second alignment marks respectively and reflect first and second reflected lights reflected from the first and second alignment marks in different horizontal directions respectively, first and second lenses arranged respectively in optical paths of the first and second reflected lights reflected from the first and second reflective surfaces of the folding mirror, first and second reflection portions configured to reflect the first and second reflected lights passing through the first and second lenses respectively, and a beam splitter prism configured to divide an illumination light incident through a first surface into the first and second illumination lights and direct to the first and second reflection portions, and transmit the first and second reflected lights reflected by the first and second reflection portions through a second surface.

Disclosed is a method and apparatus for determining information about an alignment of one or more optical components of a multi-component assembly involving: detecting an optical interference pattern produced from a combination of at least three optical wave fronts including at least two optical wave fronts caused by reflections from at least two surfaces of the one or more optical components; and computationally processing information derived from the detected optical interference pattern with at least one simulated optical wave front derived from a model of at least one selected optical surface of the at least two surfaces to computationally isolate information corresponding to an alignment of the selected optical surface.

An angle measuring device includes first and second component groups and a bearing. The first component group includes a scale element having a first graduation. The second component group has a first modular unit, including a position sensor, and a second modular unit, including first, second, and third position transducers, and a compensation coupling. The first and second modular units are connected in a torsionally stiff but axially and radially flexible manner. The angle measuring device is operable in first and second modes. In the first mode, the first graduation is scannable by the position sensor to determine a first angular position. In the second mode, the first graduation or a further graduation situated on the scale element is scannable by the position transducers to determine further angular positions. A corrected relative angular position is determinable based on the first angular position and the further angular positions.

An angle measuring device includes first and second component groups and a bearing. The first component group includes a scale element having a first graduation. The second component group has a first modular unit, including a position sensor, and a second modular unit, including first, second, and third position transducers, and a compensation coupling. The first and second modular units are connected in a torsionally stiff but axially and radially flexible manner. The angle measuring device is operable in first and second modes. In the first mode, the first graduation is scannable by the position sensor to determine a first angular position. In the second mode, the first graduation or a further graduation situated on the scale element is scannable by the position transducers to determine further angular positions. A corrected relative angular position is determinable based on the first angular position and the further angular positions.

Aspects for active alignment for assembling optical imaging systems are described herein. As an example, the aspects may include aligning an optical detector with an optical component. The optical component is configured to alter a direction of one or more light beams emitted from an image displayed by an optical engine. The aspects may further include detecting, by the optical detector, a virtual image generated by the one or more light beams emitted by the optical engine; and adjusting, by a multi-axis controller, an optical path of the one or more light beams based on one or more parameters of the virtual image collected by the optical detector.

An apparatus and a method for assembling optical module is provided and the method includes: controlling an alignment mechanism holding a to-be-assembled lens to move at a preset step-size in a preset direction when an optical module to be aligned generates an image; collecting light spots of the images generated by an optical module to be aligned sequentially by an image collecting means, each time the alignment mechanism moves; selecting a light spot with a minimum size from the collected light spots, and determining a movement position of the alignment mechanism when the light spot with the minimum size is collected, as an optimal position; controlling the alignment mechanism to move to the optimal position to align the to-be-assembled lens.

An apparatus and a method for assembling optical module is provided and the method includes: controlling an alignment mechanism holding a to-be-assembled lens to move at a preset step-size in a preset direction when an optical module to be aligned generates an image; collecting light spots of the images generated by an optical module to be aligned sequentially by an image collecting means, each time the alignment mechanism moves; selecting a light spot with a minimum size from the collected light spots, and determining a movement position of the alignment mechanism when the light spot with the minimum size is collected, as an optimal position; controlling the alignment mechanism to move to the optimal position to align the to-be-assembled lens.

The disclosure belongs to the technical field related to on-line measurement in manufacture of integrated circuit, which discloses a snapshot type overlay error measuring device and a measuring method thereof. The measuring method includes: the detection light is subjected to polarization and retardation in sequence to obtain measurement spectrum; Fourier analysis is performed on the measurement spectrum to obtain the frequency-domain signal of the measurement spectrum, and sub-channel frequency-domain analysis is performed on the frequency-domain signal to obtain the linear combination of the non-diagonal Mueller matrix elements of the overlay error sample to be tested; the linear combination of the non-diagonal Mueller matrix elements are processed to obtain the overlay error of the overlay sample under test. This disclosure does not need to measure all 16 Mueller matrix elements, the measurement is carried out on only a few non-diagonal Mueller matrix elements which are sensitive to overlay error.