Temperature-controlled autocollimator with ultrahigh angular measuring precision

Abstract

Articles you may be interested inA reference-beam autocollimator with nanoradian sensitivity from mHz to kHz and dynamic range of 107 Rev. Sci. Instrum. 84, 095007 (2013); 10.1063/1.4821653 Small angular displacement measurement based on an autocollimator and a common-path compensation principle Rev. Sci. Instrum. 84, 015108 (2013); 10.1063/1.4773004 A high-precision five-degree-of-freedom measurement system based on laser collimator and interferometry techniques Rev. Sci. Instrum. 78, 095105 (2007); 10.1063/1.2786272 Design and performance of a sub-nanoradian resolution autocollimating optical lever Rev. Sci. Instrum. 78, 035105 (2007); 10.1063/1.2714044 CCD-area-based autocollimator for precision small-angle measurement Rev.A temperature-controlled autocollimator with ultrahigh angular measuring precision is proposed in this article, which is different from our previous publication ͓J. Yuan and X. W. Long, Rev. Sci. Instrum. 74, 1362 ͑2003͔͒. The autocollimator consists of a zoom lens illuminating a charge-coupled device ͑CCD͒. This design provides a compact size and increased stability without compromising precision. Moreover, this design makes it possible to detect a target mirror with either plane reflectors or spherical reflectors. Devices for shock absorption and heat insulation were implemented to diminish external interferences. A special temperature-control system for the autocollimator is designed to control the temperature of the autocollimator. The temperature of the autocollimator fluctuates less than ±0.01°C. The CCD camera's noise is a fatal obstacle that prevents us from achieving an ultrahigh angular measuring precision. In this article, the influence of the CCD camera's noise on the measuring resolution is analyzed theoretically in detail. Based on the analysis, some special noise-suppressing methods to eliminate the influence of the CCD camera's noise are proposed. Both the influence of the CCD camera's noise and the noise-suppressing methods have not been discussed in our previous publication ͓J. Yuan and X. W. Long, Rev. Sci. Instrum. 74, 1362 ͑2003͔͒. By using the methods mentioned above, the measuring precision of the autocollimator has been greatly improved and the requirements on the external condition have been greatly reduced. The method is proved to be reliable by a prototype experiment. Two-axis angular displacement can be measured simultaneously and a measuring precision of 0.005 arcsec has been achieved, which is currently the highest measuring precision in the world.

High-precision technique for in-situ testing of the PZT scanner based on fringe analysis

“…Traditionally, optical methods for rotation angle measurement have been performed using interferometers [1][2][3], autocollimators [4][5][6] and methods based on the internal reflection [7][8][9][10]. In recent years, newer techniques, such as fringe-analysis techniques [11], Lau interferometry [12], fringe projection [13,14], and the circle Dammann grating [15], have been also developed for angle measurement.…”

Algoritmo de detección e Interfaz gráfica de usuario diseñados en Python para autocolimador digital

“…Este tipo de medición no solo introduce errores del tipo aleatorio y sistemático debido a la presencia de paralaje, propio del método utilizado, sino que también expone al operario a un continuo cansancio visual. Tanto para reducir las incertidumbres de medición y a la vez, mejorar la experiencia de medición para el operario, se suelen crear interfaces visuales para los instrumentos ópticos (Yuan, 2005;Alcock et al, 2010;Tan et al, 2007). Este ha sido el caso del autocolimador Nikon 6D que a través de sucesivos desarrollos se convirtió en un instrumento digital.…”

Electronic Interface With Vignetting Effect Reduction for a Nikon 6B/6D Autocollimator

“…A visual autocollimator can measure angles as small as 0.5 s of arc, while a digital autocollimator can be up to 100 times more accurate [6]. Digital autocollimators have a photodetector recording the position of the projected light, and thus higher resolution can be achieved, increasing the spatial resolution of the detector or by improving the data processing system [7], [8]. In addition, there are some commercial external interfaces that can be acquired to transform visual models into digital ones, such as the Davidson Optronics Digital Autocollimator Upgrade Kit, which allows existing D-652 models to have all the digital functionality of the new model D-720, digital two-axis autocollimator.…”

“…This hardware design is similar to the one in [4] and [8], in the sense that the camera is also attached to the external eyepiece of the autocollimator. The experiments in [4] and [8] were restricted to analyze the zero's long-term thermal stability of the system while we present real measurements made over a wider range of angles. Another system, an electronic reference-beam (two mirrors) autocollimator design with nanoradian sensitivity was discussed in [5].…”