An absolute surface encoder with a planar scale grating of variable periods

Shimizu, Yuki; Ishizuka, Ryo; Mano, K.; Kanda, Yoshiteru; Matsukuma, Hiraku; Gao, Wei

doi:10.1016/j.precisioneng.2020.09.007

Cited by 19 publications

(9 citation statements)

References 34 publications

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“…With the fringe density relative error of 0.001, the relative errors of the grating groove density coefficients can be controlled in the order of 10 -8 and 10 -6 , respectively. |rbe|<40μm, and R. P. is still larger than 3.7×10 4 . ξth=0.001 can meet the demands of grating groove density, aberration correction ability and resolving power.…”

Section: Impacts Of the Fringe Density Errormentioning

confidence: 90%

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Theoretical analysis on the influence of fringe density error on varied-line-spacing grating patterned with scanning beam interference lithography

Song,

Zhang,

Liu

et al. 2023

Ninth Symposium on Novel Photoelectronic Detection Technology and Applications

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Section: Impacts Of the Fringe Density Errormentioning

confidence: 90%

“…The efficiency and resolving power of instruments can be improved. VLS plane gratings are widely used as key components in extreme ultraviolet spectrum analysis, monochromators, spectral imaging, laser focusing and position sensors [1][2][3][4] .…”

Section: Introductionmentioning

confidence: 99%

Theoretical analysis on the influence of fringe density error on varied-line-spacing grating patterned with scanning beam interference lithography

Song,

Zhang,

Liu

et al. 2023

Ninth Symposium on Novel Photoelectronic Detection Technology and Applications

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“…Both types can be fabricated by mechanical diamond cutting or laser interference lithography techniques [ 6 , 7 , 8 , 9 ]. Recently, the demand for absolute-type optical encoders is increasing, in which a VLS grating serves as a scale for position measurement [ 1 , 10 , 11 ]. With the employment of a planar VLS grating having grating pattern structures along the two orthogonal directions, in-plane absolute position measurement can be achieved [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, the demand for absolute-type optical encoders is increasing, in which a VLS grating serves as a scale for position measurement [ 1 , 10 , 11 ]. With the employment of a planar VLS grating having grating pattern structures along the two orthogonal directions, in-plane absolute position measurement can be achieved [ 10 ]. However, instabilities in the mechanical manufacturing process or any distortion and imperfect wavefront control in the lithography process can result in unwanted pitch deviation of the planar VLS grating [ 12 , 13 ], which can influence its performance as the scale for two-dimensional absolute position measurement.…”

Section: Introductionmentioning

confidence: 99%

Self-Calibration of a Large-Scale Variable-Line-Spacing Grating for an Absolute Optical Encoder by Differencing Spatially Shifted Phase Maps from a Fizeau Interferometer

Xiong

Yin

Quan

et al. 2022

Sensors

Self Cite

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A new method based on the interferometric pseudo-lateral-shearing method is proposed to evaluate the pitch variation of a large-scale planar variable-line-spacing (VLS) grating. In the method, wavefronts of the first-order diffracted beams from a planar VLS grating are measured by a commercial Fizeau form interferometer. By utilizing the differential wavefront of the first-order diffracted beam before and after the small lateral shift of the VLS grating, the pitch variation of the VLS grating can be evaluated. Meanwhile, additional positioning errors of the grating in the lateral shifting process could degrade the measurement accuracy of the pitch variation. To address the issue, the technique referred to as the reference plane technique is also introduced, where the least squares planes in the wavefronts of the first-order diffracted beams are employed to reduce the influences of the additional positioning errors of the VLS grating. The proposed method can also reduce the influence of the out-of-flatness of the reference flat in the Fizeau interferometer by taking the difference between the measured positive and negative diffracted wavefronts; namely, self-calibration can be accomplished. After the theoretical analysis and simulations, experiments are carried out with a large-scale VLS grating to verify the feasibility of the proposed methods. Furthermore, the evaluated VLS parameters are verified by comparing them with the readout signal of an absolute surface encoder employing the evaluated VLS grating as the scale for measurement.

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“…The measurement accuracy is based on the grating pitch used, and the production and processing technology of the grating is related to the manufacturing process of the grating [28][29][30][31], which is less affected by the environment, and has a relatively large advantage in the realization of six-degree-of-freedom measurement. At present, the grating encoder is developing in the direction of absolute type, multiple degrees of freedom, real-time measurement and large range [32][33][34][35].…”

Section: Introductionmentioning

confidence: 99%

An ultra-precision error estimation for a multi-axes grating encoder using quadrant photodetectors

Luo

Gao²,

Wang³

et al. 2022

Optical Metrology and Inspection for Industrial Applications IX

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For expanding the measurement range and improvement of accuracy of multi-axes grating encoder, a mathematical model of measurement angle and diffraction spot with QPD was established. We proposed a light spot position calculation method with consideration of both the optimized composite algorithm of laser beam feature of Gaussian distribution and the QPD diagonal algorithm. In this method, we use the piecewise polynomial fitting method to fit and solved the parameters of the traditional Infinite integral algorithm and the Boltzmann function fitting algorithm. Meanwhile, we introduce a weight factor and use the Composite algorithm to compensate the spot position error. Based on the given QPD model and the basic parameters of the laser beam, simulation works are carried out and results show that the maximum error of the spot position can reduce to be an order of 10-6 mm within the 2 mm measurement range using piecewise cubic polynomial fitting, around 10% of the traditional methods.

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An absolute surface encoder with a planar scale grating of variable periods

Cited by 19 publications

References 34 publications

Theoretical analysis on the influence of fringe density error on varied-line-spacing grating patterned with scanning beam interference lithography

Theoretical analysis on the influence of fringe density error on varied-line-spacing grating patterned with scanning beam interference lithography

Self-Calibration of a Large-Scale Variable-Line-Spacing Grating for an Absolute Optical Encoder by Differencing Spatially Shifted Phase Maps from a Fizeau Interferometer

An ultra-precision error estimation for a multi-axes grating encoder using quadrant photodetectors

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