US 2026/0029635 A1Published application

Optical apparatus and control method of the same

AssigneeLasertec Corporation

InventorsKazuya TSURUMOTO, Nao SATO, Kenshi ISHIWATARI

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Abstract

A light source emits illumination light. An objective lens focuses the illumination light on a sample. A first detector detects reflected light at a location anterior to the focal plane of the sample. A second detector detects the reflected light at a location posterior to the focal plane of the sample. A third light detector detects the incident reflected light. A beam splitter splits the reflected light into the first and second light detectors and the third light detector. A focus adjustment mechanism adjusts a focus position of the objective lens, based on a detection result from the first and second light detectors. A optical path length adjustment mechanism is provided between the beam splitter and the first and second light detectors, and adjusts an optical distance between the beam splitter and the first and second light detectors to a value corresponding to a magnification of the objective lens.

Claims10

Dependent claims

An optical apparatus comprising:

one or more processors configured to execute a program stored in a memory;
a light source configured to emit illumination light;
an objective lens configured to focus the illumination light on a sample;
a first detector configured to detect a secondary light beam generated by illuminating the sample with the illumination light at a location anterior to the focal plane of the sample;
a second detector configured to detect the secondary light beam at a location posterior to the focal plane of the sample;
a third detector configured to detect the secondary light beam incident via the objective lens;
a beam splitter configured to split the secondary light beam into the first and second detectors and the third detector;
a focus adjustment mechanism configured to adjust a focus position of the objective lens in response to control instructions, wherein the one or more processors are further configured to generate the control instructions for the focus adjustment mechanism based on detection results from the first and second detectors;
and
an optical path length adjustment mechanism located between the beam splitter and the first and second detectors, and configured to adjust an optical path length in accordance with a magnification of the objective lens.

7 more elements

Dependencies are inferred from the claim text.