摘要:
In an optical type encoder for projecting a light beam onto an optical type scale having a diffraction grating formed thereon, forming an interferenced light by the use of a diffracted light from the scale, and photoelectrically converting the interferenced light to thereby measure the displacement of the scale, first and second light beams are caused to enter substantially the same position on the scale from different first and second directions, first and second diffracted light beams emerging from the scale by the first and second light beams being diffracted by the scale are directed to the aforementioned position by a reflecting device, the diffracted light beams emerging in the first and second directions by the first and second diffracted light beams being diffracted by the scale are superposed one upon the other to thereby form an interferenced light, and light components created by the first and second light beams being regularly reflected at the aforementioned position are not included in the interferenced light.
摘要:
A displacement measuring apparatus comprises a scale relatively displaced to an irradiating beam, a reading head to read the scale by the irradiating beam, and control device to control the apparatus for avoiding substantially the leakage of the irradiating beam out of the apparatus in response to the positional error of the scale and the irradiating beam.
摘要:
A displacement measuring apparatus has an illuminating device for illuminating a diffraction grating with a radiation beam, an optical system for directing first and second diffracted beams created by the diffraction grating with to the diffraction grating, the optical system being provided so that the first and second diffracted beams have a common optical path and travel in opposite directions along the optical path. In addition, a device receives an interference beam formed by first and second re-diffracted beams created by the first and second diffracted beams being diffracted by the diffraction grating, and outputs a signal conforming to the displacement of the diffraction grating relative to the radiation beam.
摘要:
A rotary encoder for detecting a rotation status of a rotary scale having a diffraction grating formed along a rotational direction comprises a directing device for directing a radiation beam to a first position on the rotary scale and directing a plurality of diffracted beams generated at the first position to a second position different from the first position. The direction device is constructed such that the plurality of diffracted beams gave a common light path between the first position and the second position. The encoder also includes a forming device for forming an interference beam from a plurality of rediffracted beams generated at the second position, and a convertor for converting the interference beam to a signal to produce the signal representing the rotation status.
摘要:
An encoder for measuring the displacement of a movable diffraction grating has means for applying a radiation beam to the diffraction grating, a reflecting optical system for causing first and second reflected and diffracted beams created on the diffraction grating by the application of the radiation beam to be reflected and diffracted at least twice by the diffraction grating, and means for receiving an interference beam formed by the first and second reflected and diffracted beams reflected and diffracted at least twice and converting it into a signal conforming to the displacement of the diffraction grating.
摘要:
An encoder in which a light beam emitted from a semiconductor laser or the like is applied to a diffraction grating from a predetermined direction which is not contained in a reference plane defined by direction of relative movement of the diffraction grating and a direction normal to the diffraction grating. A diffracted light created from the diffraction grating by the application of the light beam by the light applying means is reflected by re-entering means and the reflected light is caused to re-enter the diffraction grating at substantially the same position as the position at which the diffracted light is created. At this time, an interference light formed by the other re-diffracted lights than O-order light created from the diffraction grating substantially in the same direction as the predetermined direction by the re-entrance of the diffracted light by the re-entering means is detected, and the information of the relative displacement of the light beam and the diffraction grating is obtained from a variation in the intensity of the interference light.
摘要:
A method for detecting a state of rotation of a rotary scale having a diffraction grating therein in which a radiation beam is directed to a first place on the diffraction grating to generate first and second diffracted beams. The first and second diffracted beams are re-diffracted at the first place to form a first re-diffracted beam and a second re-diffracted beam. The first and second re-diffracted beams are directed to a second place on the diffraction grating substantially opposite the first place with respect to the center of rotation of the rotary scale. The first and second re-diffracted beams are diffracted at the second place to interfere with each other so that an interference beam is formed. The interference beam is converted into a signal to detect the state of rotation of the rotary scale.
摘要:
An encoder having a long length measuring stroke with a simple construction is provided. The encoder comprises a scale formed with a periodic lattice pattern, first and second reading heads arranged along a moving direction of the scale for reading the scale, and an adder for adding output signals from the first and second reading heads. The encoder further has adjusting mechanism for adjusting such that the phase difference between the output signals from the first and second reading head becomes zero. A continuous periodic signal can be always accurately obtained independently of the position of the scale.
摘要:
A device comprises output device for receiving signals having predetermined phases and outputting first and second signals having different phase angles and amplitudes, conversion device for converting the first signal into a first binary signal and the second signal into a second binary signal, the conversion device being arranged so that widths of the first and second binary signals are substantially equal to each other regardless of a difference in amplitude of the first and second signals, and generating device for generating first and second pulses according to phase angles on the basis of the first and second binary signals.
摘要:
An encoder for detecting the state of movement of a scale having a plurality of tracks consisting of arranged predetermined codes comprises first detecting device for reading the codes of the plurality of tracks and detecting data comprising a row of the codes, and second detecting device for detecting the state of movement of the codes of a particular track plurality of tracks to obtain more detailed data. The state of movement of the scale is detected on the basis of the signals from the first and second detecting devices.