A height measurement device includes: a lens system; a lens controller to output a drive signal to the lens system; a continuous illuminator to continuously illuminate a workpiece; an image detector to detect an image of the workpiece; an image calculation unit to calculate an EDOF image on a basis of a detected image; a focal depth adjustment unit to cause an extended focal depth of the EDOF image to be increased or decreased by increasing or decreasing an amplitude of the drive signal; a focus determination unit to determine a focus state of a portion of interest of the workpiece included in the EDOF image; and a height measurement unit to measure an upper limit or a lower limit of the extended focal depth, the upper limit or the lower limit being based on a timing at which the focus state of the portion of interest has changed.

An apparatus for evaluating focus, including (a) a stage configured to hold a specimen; and (b) an optical train including a radiation source, calibration optic, objective and detector, the optical train forming a first path wherein radiation from the radiation source is directed to the calibration optic and then a first portion of the radiation is directed to the detector, thereby forming a first image on the detector, wherein a second portion of the radiation follows a second path from the calibration optic then through the objective to the specimen, wherein the optical train forms a third path wherein radiation reflected from the specimen is transmitted through the objective, then to the detector, thereby forming a second image on the detector, and wherein the radiation that forms the first image is astigmatic.

An auto-focusing system is disclosed. The system includes an illumination source. The system includes an aperture. The system includes a projection mask. The system includes a detector assembly. The system includes a relay system, the relay system being configured to optically couple illumination transmitted through the projection mask to an imaging system. The relay system also being configured to project one or more patterns from the projection mask onto a specimen and transmit an image of the projection mask from the specimen to the detector assembly. The system includes a controller including one or more processors configured to execute a set of program instructions. The program instructions being configured to cause the one or more processors to: receive one or more images of the projection mask from the detector assembly and determine quality of the one or more images of the projection mask.

A holder for a microscope slide includes a receiving area that has a first contact surface and a second contact surface opposite the first contact surface, a first counter-surface that at least partially spans the first contact surface, and a second counter-surface that at least partially spans the second contact surface. The receiving area is bounded on three sides by side elements and has an opening on one side for insertion of the microscope slide. At least one pressure element is arranged within the receiving area and configured to exert a restoring force directed towards an interior of the receiving area.

A method for performing microscopy-based imaging of samples comprises: loading a sample holder (100) onto a support (50) configured to receive the sample holder (100); moving the sample holder (100) in a first direction, from a starting position on a first strip of the sample holder (100), to move the sample holder (100) relative to an imaging line of a line camera (10), to capture an image of the first strip of the sample holder (100); monitoring a focal plane using an autofocus system (15) as the sample holder (100) is moved in the first direction; in response to a signal from the autofocus system (15), moving an objective lens (25) along the optical axis to adjust the focal plane; and moving the sample holder (100) in a second direction, to align the imaging line of the line camera (10) with a position on a second strip of the sample holder (100).

Systems and methods for capturing a digital image of a slide using an imaging line sensor and a focusing line sensor. In an embodiment, a beam-splitter is optically coupled to an objective lens and configured to receive one or more images of a portion of a sample through the objective lens. The beam-splitter simultaneously provides a first portion of the one or more images to the focusing sensor and a second portion of the one or more images to the imaging sensor. A processor controls the stage and/or objective lens such that each portion of the one or more images is received by the focusing sensor prior to it being received by the imaging sensor. In this manner, a focus of the objective lens can be controlled using data received from the focusing sensor prior to capturing an image of a portion of the sample using the imaging sensor.

An optical system used in a charged particle beam inspection system. The optical system includes one or more optical lenses, and a compensation lens configured to compensate a drift of a focal length of a combination of the one or more optical lenses from a first medium to a second medium.

A method for controlling microscopic imaging of a microscope includes providing a microscope control arrangement configured for receiving a focusing request and for receiving sample information on a sample to be imaged, wherein the microscope control arrangement activates, upon receipt of a focusing request and after having received the sample information, a predefined focusing setting depending on the sample information received for controlling focusing of the microscope for microscopic imaging of the sample.

An autofocus system includes a focus light source, an objective lens, a defocus lens, a first image sensor, and a controller. The defocus lens is disposed on the transmission path of the focus light beam, so that a minimum light point of the focus light beam passing through the objective lens deviates from a focus of the objective lens. The first image sensor is configured to receive a focus reflected light beam generated after the focus light beam is reflected by the sample. The controller is electrically connected to the first image sensor. According to a center change of gravity, a position change, or an energy change of a light spot formed by the focus reflected light beam on an image plane of the first image sensor, the controller drives the objective lens or the sample to move, so that the focus of the objective lens falls on the sample.

Disclosed are several technical approaches of using low coherence interferometry techniques to create an autofocus apparatus for optical microscopy. These approaches allow automatic focusing on thin structures that are positioned closely to reflective surfaces and behind refractive material like a cover slip, and automated adjustment of focus position into the sample region without disturbance from reflection off adjacent surfaces. The measurement offset induced by refraction of material that covers the sample is compensated for. Proposed are techniques of an instrument that allows the automatic interchange of imaging objectives in a low coherence interferometry autofocus system, which is of major interest in combination with TDI (time delay integration) imaging, confocal and two-photon fluorescence microscopy.