Calibration of a non-null test interferometer for the measurement of aspheres and free-form surfaces

Baer, Goran; Schindler, Johannes; Pruß, Christof; Siepmann, Jens; Osten, Wolfgang

doi:10.1364/oe.22.031200

Cited by 75 publications

(64 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A key factor of the TWI is an effective calibration concept. 33,34 It takes the common standard calibration from a two-dimensional (2-D) areal calibration to a volume calibration. This allows placing the SUT at any suitable position in front of the interferometer, which greatly enhances the flexibility of the instrument.…”

Section: Tilted Wave Interferometermentioning

confidence: 99%

Measuring aspheres quickly: tilted wave interferometry

Pruß

Baer²,

Schindler

2017

Opt. Eng

Self Cite

View full text Add to dashboard Cite

Abstract. Functional surfaces with a rising degree of complexity are becoming increasingly important for modern industrial products. It is common knowledge that one cannot produce surfaces better than it is possible to measure them. Consequently, the demand for their effective and precise measurement has increased to the same extent as their production capabilities have grown. Important classes of optical functional surfaces are aspheres and freeforms. Both types of surfaces have become essential parts of modern optical systems such as laser focusing heads, sensors, telescopes, glasses, head-mounted displays, cameras, lithography steppers, and pickup heads. For all of them, the systematic quality control in the process of their fabrication is essential. We review the challenges of asphere and freeform testing and how available metrology systems cope with it. A special focus is on tilted wave interferometry and how it compares to other methods. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

show abstract

Section: Tilted Wave Interferometermentioning

confidence: 99%

Measuring aspheres quickly: tilted wave interferometry

Pruß

Baer²,

Schindler

2017

Opt. Eng

Self Cite

View full text Add to dashboard Cite

show abstract

“…8,12,13 It is based on a Twyman-Green interferometer, but instead of a single light source it uses a two-dimensional point light source array (PLA). 2.2 was measured with two different methods.…”

Section: Form Measurementmentioning

confidence: 99%

“…They benefit from additional degrees of freedom in contrast to conventional surface forms. 8 We have developed a multispherical freeform artifact with an optical surface which aims to fulfill the requirements of a performance test of tactile touch probe and contact-free optical measuring systems. [1][2][3][4] Freeforms enable new opportunities in optical performance and create challenges for manufacturing and metrology.…”

Section: Introductionmentioning

confidence: 99%

Metrological multispherical freeform artifact

et al. 2016

Self Cite

View full text Add to dashboard Cite

Precisely known artifacts are required to characterize the accuracy of asphere and freeform measuring instruments. To this end the best knowledge of the surface characteristics in conjunction with a low measurement uncertainty are necessary. Because this is a challenging task for typical freeform surfaces used in optical systems, the concept of "metrological" artifacts is introduced. We have developed a multispherical freeform artifact for performance tests of tactile touch probe and contact-free optical measuring systems. The measurement accuracy of the complete form and the deviation from calibrated spherical sections can thus be determined. The radius calibration of multiple spherical sections is performed with an extended radius measuring procedure by interferometry. Evaluated surface forms of different measuring methods and the radii determined can be compared to each other. In this study, a multispherical freeform specimen made of copper, with two differing radii, has been measured by two optical measuring methods, a full field measuring tilted-wave interferometer and a high accuracy cylinder coordinate measuring machine with an optical probe. The surface form measurements are evaluated and compared, and the radii determined are compared to the results of a radius measurement bench.

show abstract

“…For this "calibration" of the optical model, known reference spheres are measured at different positions. These measurement data are used to adapt the wavefront description in two reference planes of the optical system by solving yet another inverse problem [13]. The mathematical evaluation principle [11,14] is summarized below.…”

Section: Interferometric Measurement Of Aspheresmentioning

confidence: 99%

Traceability in interferometric form metrology

et al. 2015

View full text Add to dashboard Cite

The concept of traceability is presented for the interferometric form measurement of optical surfaces. The calibration chain for interferometric flatness measurement is evaluated in detail, showing that only a few influence quantities are significant. For spherical surfaces, the complexity increases as the measurement separates into sphericity and radius measurement. Traceability in asphere metrology is much more complex, and some aspects are discussed in terms of the example of the Tilted-Wave Interferometer concept.

show abstract

Calibration of a non-null test interferometer for the measurement of aspheres and free-form surfaces

Cited by 75 publications

References 7 publications

Measuring aspheres quickly: tilted wave interferometry

Measuring aspheres quickly: tilted wave interferometry

Metrological multispherical freeform artifact

Traceability in interferometric form metrology

Contact Info

Product

Resources

About