公开(公告)号：US20230288184A1

公开(公告)日：2023-09-14

申请号：US17950193

申请日：2022-09-22

Applicant: SEIKO EPSON CORPORATION

Inventor： Jun KITAGAWA

IPC: G01B9/02001 ,  G02B27/30 ,  G02B27/12

CPC classification number: G01B9/02007 ,  G02B27/12 ,  G02B27/30

Abstract: There is provided a laser interferometer. The laser interferometer includes a laser light source; a first light splitter configured to split the laser light into first split light and second split light; an optical modulator configured to modulate the first split light into reference light from the first split light; a second light splitter configured to split the reference light and object light generated by an object to be measured reflecting the second split light into third split light and fourth split light; a first light receiving element configured to receive the third split light; and a second light receiving element configured to receive the fourth split light. An optical axis of the first split light that travels from the first light splitter toward the optical modulator is shifted from an optical axis of the reference light that travels from the optical modulator toward the first light splitter. A difference between an optical path length from the second light splitter to the first light receiving element and an optical path length from the second light splitter to the second light receiving element is 20 mm or less.

公开(公告)号：US20220065613A1

公开(公告)日：2022-03-03

申请号：US17410798

申请日：2021-08-24

Applicant: SEIKO EPSON CORPORATION

Inventor： Jun KITAGAWA

IPC: G01B9/02

Abstract: A laser interferometer includes a light source that emits first laser light, an optical modulator that includes a vibrator and modulates the first laser light by using the vibrator to generate second laser light including a modulated signal, a photodetector that receives interference light between third laser light including a sample signal generated by reflecting the first laser light on an object and the second laser light to output a light reception signal, and an optical path length variable section that changes an optical path length of an optical path through which the third laser light propagates.

公开(公告)号：US20240384978A1

公开(公告)日：2024-11-21

申请号：US18664376

申请日：2024-05-15

Applicant: SEIKO EPSON CORPORATION

Inventor： Jun KITAGAWA ,  Kohei YAMADA ,  Nobuhito HAYASHI

IPC: G01B9/02001 ,  G01B9/02

Abstract: A laser interferometer includes an optical interference unit as a non-coaxial optical system including a laser source for emitting a laser beam, a light modulator for modulating a frequency of the laser beam to generate reference light, a light receiving element for receiving object light generated in response to irradiation of an object with the laser beam, and the reference light to output a received light signal, a first aperture element disposed on a light path entering the light receiving element, and for detecting a positional deviation of an optical axis of the object light from an optical axis of the reference light, and an angular deviation detection unit for detecting an angular deviation of the optical axis of the object light from the optical axis of the reference light based on the received light signal, and an instruction unit for issuing an instruction to change a relative arrangement between the optical interference unit and the object based on a detection result of the positional deviation and a detection result of the angular deviation.

公开(公告)号：US20240151643A1

公开(公告)日：2024-05-09

申请号：US18503406

申请日：2023-11-07

Applicant: SEIKO EPSON CORPORATION

Inventor： Jun KITAGAWA

IPC: G01N21/45

CPC classification number: G01N21/45 ,  G01N2201/06113

Abstract: Provided is a laser interferometer including: a laser light source configured to emit laser light; an optical modulator including a vibrator that has a light reflection surface and vibrates in response to a drive signal, the optical modulator being configured to overlap a modulation signal on the laser light by reflecting the laser light on the light reflection surface; and a photodetector configured to receive the laser light including a sample signal derived from an object and the modulation signal, and to output a light-receiving signal. When an inclination angle θqom is defined by a normal line of the light reflection surface and an incident optical axis of the laser light incident on the light reflection surface, the following Relationship (1) is satisfied.


0[deg]