An interference observation apparatus includes a light source, a splitting beam splitter, a combining beam splitter, a beam splitter, a mirror, a beam splitter, a mirror, a piezo element, a stage, an imaging unit, an image acquisition unit, and a control unit. An interference optical system from the splitting beam splitter to the combining beam splitter forms a Mach-Zehnder interferometer. The mirror freely moves in a direction perpendicular to a reflecting surface of the mirror. The total number of times of respective reflections of first split light and second split light in the interference optical system is an even number.

An optical coherence tomograph includes a wavelength tunable illuminating device, an illumination and measurement beam path with a dividing element and a scanner and a front optical unit and a reference beam path, a detection beam path and a flat panel detector. A beam splitter conducts the separated measurement radiation to the detection beam path and an optical element acts only on the illumination radiation. The optical element sets the numerical aperture of the illumination of the illumination field in the eye. An optical element acts only on the measurement radiation and sets the numerical aperture with which measurement radiation is collected in the eye. An aperture is arranged in front of the flat panel detector in an intermediate image plane and defines the size of an object field. The flat panel detector has a spatial resolution of 4 to 100 pixels in a direction.

The present invention relates to a method and an assembly for chromatic confocal spectral interferometery, in particular also for spectral domain OCT (SD-OCT) using multi-spectral light. A multiple (e.g. two, three, four, etc.) axial splitting of foci in the interferometric object arm is performed using a multifocal (e.g. bifocal, trifocal, quattro-focal, etc.) optical component, forming thereby at least two, three or even several groups of chromatically split foci in the depth direction. The multifocal optical component is made of a diffractive optical element (712) and a Schwarzschild objective (5). At least two, three, four or even more differently colored foci of different groups of foci coincide in at least one confocal point in the object space of the setup. Thus, at least two, three or even more spectral wavelets are formed in the case of optical scanning of an object measurement point and spectral detection in the wavenumber domain, which wavelets are at least slightly spectrally separated from each other. This results in a significant increase in the optical primary data in the wavenumber domain and reduces the trade-off of the chromatic confocal spectral interferometry between axial measurement range and depth resolution. From the detected data, it is possible to calculate tan (alpha) as the quotient of the absolute phase shift delta_phi and the associated wavenumber difference delta_k, the Fourier transform over the spectral data, in order to respectively determine the optical path difference.

The present invention relates to a wafer carrier thickness measuring device capable of accurately measuring an inner/outer circumferential thickness of a wafer carrier in a non-contact manner. The present invention provides a wafer carrier thickness measuring device including: a first table installed to be capable of rotating and moving vertically and capable of supporting a central portion of a wafer carrier; a second table disposed outside the first table and rotatably installed, and capable of supporting an outer circumferential portion of the wafer carrier; upper and lower sensors for calculating a thickness of the wafer carrier by measuring a distance to upper and lower surfaces of the wafer carrier supported by one of the first and second tables in a non-contact manner; and a sensor driving unit located at one side of the second table and moving the upper and lower sensors to an upper side or a lower side of the wafer carrier supported by one of the first and second tables.

A sensor head is provided and achieves improved measurement accuracy while reducing measurement time. The sensor head includes: a case including a first case section having a lens therein, a second case section having an objective lens therein, and a third case section providing connection between the first case section and the second case section. Inside the third case section, a mirror member for folding light incident thereon from the lens toward the objective lens is disposed, and a hollow tube providing communication between through holes respectively formed in the mirror member and the objective lens is provided.

Methods and systems for focusing and measuring by mean of an interferometer device, having an optical coherence tomography (OCT) focusing system, by separately directing an overlapped measurement and reference wavefront towards a focus sensor and towards an imaging sensor; where a predefined focusing illumination spectrum of the overlapped wavefront is directed towards the focus sensor, and where a predefined measurement illumination spectrum of the overlapped wavefront is directed towards the imaging sensor. Methods and systems for maintaining focus of an interferometer device, having an OCT focusing system, during sample's stage moves.

The optical measuring device includes a light source that outputs light of a plurality of wavelengths; a sensor head including a conversion lens that converts light incident via a light guide part, which includes a plurality of cores, into parallel light, and an objective lens that irradiates the light in which chromatic aberration is generated to a measurement object; and a spectroscope that acquires reflected light reflected by the measurement object and condensed by the sensor head via the light guide part and measures a spectrum of the reflected light. In the sensor head, a shield that shields light is arranged between the conversion lens and the objective lens to inhibit light emitted from one core among the plurality of cores included in the light guide part from entering cores other than the one core as the reflected light.

A sensor head is provided and achieves improved measurement accuracy while reducing measurement time. The sensor head includes: a case including a first case section having a lens therein, a second case section having an objective lens therein, and a third case section providing connection between the first case section and the second case section. Inside the third case section, a mirror member for folding light incident thereon from the lens toward the objective lens is disposed, and a hollow tube providing communication between through holes respectively formed in the mirror member and the objective lens is provided.

Provided is a device for measuring a lens three-dimensional profile based on laser wavenumber scanning, including: a semiconductor laser for emitting coherent light; a beam splitter for dividing the coherent light into two parts; an optical wedge; a CCD camera for capturing an interference image; a computer for processing image information; a laser controller for adjusting an operating temperature and an operating current of the semiconductor laser; and a bilateral telecentric lens. The coherent light is reflected by the optical wedge and then reaches the bilateral telecentric lens through the beam splitter, to form a first reflected light path. The coherent light is reflected by the measured lens, and then reaches the bilateral telecentric lens through the beam splitter, to form a second reflected light path. The first reflected light path and the second reflected light path form an interference image after passing through the bilateral telecentric lens.

The present invention relates to a wafer carrier thickness measuring device capable of accurately measuring an inner/outer circumferential thickness of a wafer carrier in a non-contact manner. The present invention provides a wafer carrier thickness measuring device including: a first table installed to be capable of rotating and moving vertically and capable of supporting a central portion of a wafer carrier; a second table disposed outside the first table and rotatably installed, and capable of supporting an outer circumferential portion of the wafer carrier; upper and lower sensors for calculating a thickness of the wafer carrier by measuring a distance to upper and lower surfaces of the wafer carrier supported by one of the first and second tables in a non-contact manner; and a sensor driving unit located at one side of the second table and moving the upper and lower sensors to an upper side or a lower side of the wafer carrier supported by one of the first and second tables.