Abstract

Birefringence in the plastic lenses of optical pickups (OPs) arises from preferential molecular orientation and internal stresses. This birefringence introduces astigmatic aberration to the transmitted wavefront when a polarized light is incident on the lens. It is necessary to quantitatively measure this birefringence-induced astigmatism (BIA) since it affects the aberration of the focused spot on the disk which, in turn, influences the readout signals of the drive system. The measurement of this astigmatism is, however, complicated by the fact that it couples with the astigmatism resulting from the deviation of the lens’s shape, owing to fabrication errors of the molding inserts, from its originally designed formula. This paper presents a method for analyzing these two components of astigmatism separately so that the BIA of OP lenses can be evaluated.

© 2000 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. B.E. Bernacki, M. Mansuripur, “Investigation of substrate birefringence effects on optical-disk performance,” Appl. Opt. 32, 6547-55 (1993).
    [CrossRef] [PubMed]
  2. S. Sugaya, M. Mansuripur, “Effect of tilted ellipsoid of birefringence on readout signal in magneto-optical disk data storage,” Appl. Opt. 33, 5999-6008 (1994).
    [CrossRef] [PubMed]
  3. K.M. Hung, “Effects of asymmetrically molded plastic objective lens on push-pull tracking error signal in an optical disk drive,” Appl. Opt. 39, 1309-14 (2000).
    [CrossRef]

2000

1994

1993

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (4)

Figure 1
Figure 1

Twyman-Green interferometer for measuring the transmission wavefront distortion of OP lenses. LD stands for laser diode; SF is the spatial filter; CM is the collimator; P is the polarizer; NPBS is the non-polarized beam splitter; MO is the microscope objective; SM is the spherical mirror; M1 and M2 are flat mirrors: PZM is a piezoelectric-driven mirror; IU is the imaging unit and CCD stands for CCD camera.

Figure 2
Figure 2

Astigmatism contour of the PMMA lens. The dots are obtained with a non-polarized beam; the triangles are obtained with polarized light in the y-direction. The angles indicated are the values of β.

Figure 3
Figure 3

Astigmatism data of the Zeonex lens obtained with polarized light in the y-direction. The angles indicated are the values of β.

Figure 4
Figure 4

Astigmatism data of the Zeonex lens obtained by rotating the polarization direction (indicated by the angles) of the beam when the lens is at (a) β = 0°, and (b) β = 90°.

Metrics