Hybrid displacement measuring device

A hybrid displacement measuring device, characterized by comprising:

• a worktable to be measured;
• a grating ruler;
• a laser light source, which is used to generate a laser beam;
• a first beam splitting mirror, which is positioned at an output end of the laser light source, and which is used to split the laser beam to generate a first basic reflected beam and a first basic transmitted beam;
• a first measuring assembly, which is positioned on the optical path of the first basic reflected beam, and which comprises a turning mirror combination and a reading head combination, the reading head combination comprising at least one reading head, the turning mirror combination being used to turn the first basic reflected beam to the grating ruler, such that the grating ruler diffracts the first basic reflected beam and generates a diffracted beam, the turning mirror combination being also used to turn the diffracted beam to the reading head, the reading head being used to generate, according to the diffracted beam, first displacement information of the worktable to be measured;
• and
• a second measuring assembly, which comprises a first reflective mirror and a first interferometer, the first interferometer and the first reflective mirror being positioned on the optical path of the first basic transmitted beam sequentially, the first reflective mirror being positioned on the worktable to be measured, and being used to reflect the first basic transmitted beam to the first interferometer, the first interferometer being used to generate, according to the first basic transmitted beam reflected by the first reflective mirror, second displacement information of the worktable to be measured;
• the first beam splitting mirror, the turning mirror combination, and the first reflective mirror being all maintained fixed relative to the worktable to be measured;
• the turning mirror combination comprising:
• a second reflective mirror, which is positioned on the optical path of the first basic reflected beam;
• a second beam splitting mirror, which is positioned facing a reflection surface of the second reflective mirror, and which is used to split the first basic reflected beam turned by the second reflective mirror to generate a first reflected beam and a first transmitted beam, the first reflected beam being turned by the second beam splitting mirror to the grating ruler, such that the grating ruler diffracts the first reflected beam and generates a first primary diffracted beam;
• a first turning mirror, which is positioned on the optical path of the first primary diffracted beam, and which is used to turn the first primary diffracted beam to the second beam splitting mirror, through which the first primary diffracted beam is transmitted the reading head;
• a third reflective mirror, which is positioned on the optical path of the first transmitted beam, and which is used to turn the first transmitted beam to the grating ruler, such that the grating ruler diffracts the first transmitted beam and generates a second primary diffracted beam;
• a second turning mirror, which is positioned on the optical path of the second primary diffracted beam, and which is used to turn the second primary diffracted beam;
• and
• a fourth reflective mirror, which is positioned on the turning path of the second primary diffracted beam, and which is used to turn the second primary diffracted beam to the second beam splitting mirror, where the second primary diffracted beam is reflected to the reading head;
• the first primary diffracted beam and the second primary diffracted beam generating an interference signal, and the reading head generating the first displacement information according to the interference signal.