An automatic focus system for an optical microscope that facilitates faster focusing by using at least two offset focusing cameras. Each offset focusing camera can be positioned on a different side of an image forming conjugate plane so that their sharpness curves intersect at the image forming conjugate plane. Focus of a specimen can be adjusted by using sharpness values determined from images taken by the offset focusing cameras.

An automatic focus system for an optical microscope that facilitates faster focusing by using at least two offset focusing cameras. Each offset focusing camera can be positioned on a different side of an image forming conjugate plane so that their sharpness curves intersect at the image forming conjugate plane. Focus of a specimen can be adjusted by using sharpness values determined from images taken by the offset focusing cameras.

A method refocuses on an optical assembly target surface, using at least one beam originating from a short-pulse optical source, having at least one optical system for focusing the beam on the surface. Refocusing occurs after learning reference conditions for which the assembly is considered as focused. A focusing signal is detected representing a time overlap of the pulses between a beam reflected and a reference beam not reflected by the surface and comes from the source, one of the beams delayed by a delay line, the beam optical path on which the delay line is placed is varied, on the basis of the reference conditions, to cause the focusing signal to reach or go beyond a predetermined threshold. The focus is adjusted on the basis of variation knowledge in the path between the reference conditions and the conditions for which the focusing signal reaches or goes beyond the threshold.

An automatic focus system for an optical microscope that facilitates faster focusing by using at least two offset focusing cameras. Each offset focusing camera can be positioned on a different side of an image forming conjugate plane so that their sharpness curves intersect at the image forming conjugate plane. Focus of a specimen can be adjusted by using sharpness values determined from images taken by the offset focusing cameras.

A digital microscope apparatus includes a first imaging unit including a first imaging device and a first optical system including an objective lens configured to enlarge first and second images of a preparation that holds a sample, the first image being formed on the first device through the first system, a second imaging unit including a second optical system that is branched from the first system and has a depth of field larger than the first system and a second imaging device on which the second image is formed through the second system, and a controller configured to calculate a provisional in-focus position of the lens based on the second image, determine an area of the first device, from which the first image is read, and search for, based on the read image, an in-focus position of the lens in a predetermined range based on the provisional in-focus position.

An automatic focus system for an optical microscope that facilitates faster focusing by using at least two offset focusing cameras. Each offset focusing camera can be positioned on a different side of an image forming conjugate plane so that their sharpness curves intersect at the image forming conjugate plane. Focus of a specimen can be adjusted by using sharpness values determined from images taken by the offset focusing cameras.

An automatic focus system for an optical microscope that facilitates faster focusing by using at least two offset focusing cameras. Each offset focusing camera can be positioned on a different side of an image forming conjugate plane so that their sharpness curves intersect at the image forming conjugate plane. Focus of a specimen can be adjusted by using sharpness values determined from images taken by the offset focusing cameras.

There is provided a microscope focus control system comprising an illumination source (70) and a polarisation-sensitive detector (66) positioned to receive a reflected beam (40) from an interface (54) having a reference refractive index and configured to detect polarisation components of the reflected beam (40). An elongate aperture (72) is disposed proximal the illumination source (70) to generate a rectangular beam (74) to impinge on the interface (54) and a second aperture (106) is located at a position corresponding to an unfocused region of the reflected beam (40) from the interface (54) so as to direct unfocused reflected light onto the polarisation-sensitive detector (66). Changes in polarisation components of the reflected beam are used to measure of change in position of the interface (54) relative to the objective (50). The reflected beam (40) is generated by Fresnel reflection.

The invention is based on an autofocus method in which light from a light source is focused at a measurement light focus in a sample and is reflected from there and the reflected light is guided through an optical system in two light paths onto at least two detector elements. In order to achieve fast and accurate automatic focusing on the sample, it is proposed that the measurement light focus is moved in layers of the sample which reflect light to different extents, and the detector elements are arranged in such a way that, in this case, profiles of a radiation property registered by the detector elements are different and a focus position is set in a manner dependent on the profiles.

An automatic focus system for an optical microscope that facilitates faster focusing by using at least two offset focusing cameras. Each offset focusing camera can be positioned on a different side of an image forming conjugate plane so that their sharpness curves intersect at the image forming conjugate plane. Focus of a specimen can be adjusted by using sharpness values determined from images taken by the offset focusing cameras.