Summary
We have developed a novel transmissive nematic liquid crystal device which is capable of compensating spherical wavefront aberration that occurs during the operation of optical pickup systems. In order to increase the storage capacity, next generation optical data storage systems beyond CD and DVD will use according to the Blu-Ray specification (BD) blue laser light and an objective lens with high numerical aperture (N.A.) of 0.85. However, such high N.A. systems have an inherent higher sensitivity on aberrations. For example spherical aberration is inversely proportional to the wavelength and grows with the fourth power of N.A. of the objective lens. In an optical pickup system there are two sources for spherical aberration: The first one is the variation of the substrate thickness due to manufacturing tolerances under mass production conditions. The second one concerns disks with multiple data-layers, which cause spherical aberration when layers are switched, as the objective lens can only be optimized for a single layer thickness. We report a method for effective compensation of spherical aberration by utilizing a novel liquid crystal device, which generates a parabolic wavefront profile. This particular shape makes the device highly tolerant against lateral movement. A sophisticated electrode design allows us to reduce the number of driving electrodes down to two by using the method of conductive ladder mashing. Further evaluation in a blue-DVD test drive has been carried out with good results. By placing the device into an optical pick-up we were able to readout a dual-layer ROM disk with a total capacity of 50 gigabytes (GB). A data-to-clock jitter of 6.9% for the 80 μm and of 8.0% for the 100 μm cover layer could be realized.
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References
S. Stallinga, J. Vrehen, J. Wals, H. Stapert, E. Verstegen: Liquid crystal aberration compensation devices. Optical storage and optical information processing.Proc. SPIE 4081, 50 (2000)
S. Ohtaki, N. Murao, M. Ogasawara, M. Iwasaki: The applications of a liquid crystal panel for the 15 GByte optical disk system. Jpn. J. Appl. Phys. 38, 1744 (1999)
J. Braat: Influence of substrate thickness on optical disk readout. Appl. Opt. 36, 8056 (1997)
J. Knittel, H. Richter, M. Hain, S. Somalingam, T. Tschudi: A liquid crystal lens for spherical aberration compensation in a blu-ray disc system. To be published
S. Miyanabe, H. Kuribayashi, K. Yamamoto: New equalizer to improve signalto-noise ratio. Jpn. J. Appl. Phys. 38, 1715 (1999)
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© 2005 Springer-Verlag Berlin Heidelberg
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Somalingam, S., Hain, M., Tschudi, T., Knittel, J., Richter, H. (2005). Aberration Compensation Using Nematic Liquid Crystals. In: Wittrock, U. (eds) Adaptive Optics for Industry and Medicine. Springer Proceedings in Physics, vol 102. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-28867-8_5
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DOI: https://doi.org/10.1007/3-540-28867-8_5
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-23978-9
Online ISBN: 978-3-540-28867-1
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