Optical Pickup Bobbins Grades of SUMIKASUPER LCP

Grade Selection Guide for Optical Pickup Bobbins

What are Optical Pickup Bobbins?

Optical pickup bobbins are key components used in the following devices: optical disc reading units for CD, DVD and Blu-ray devices; and optical disc reader/writer units used for them. Optical pickup bobbins are commonly manufactured out of SUMIKASUPER LCP.

Properties Required for Optical Pickup Bobbin Material

Optical disc drives are able to perform data reading and writing operations by applying laser beam onto minute pits on the disc, with dimensions in the μm (1/1000 mm), that have been engraved into optical discs. When reading and writing data, the focusing lens itself must be moved at extremely high speeds, using magnetic forces, in order to be able to focus the laser beam onto the correct sections of the disc, as it rotates at high speed. Coils are utilized to provide the magnetic force to move the lens. The lens is mounted on top of the optical pickup bobbin, as shown in the figure below, thus the bobbin can also be referred to as the "lens holder".

Structure of the Beam Pickup Bobbin

The properties required of optical pickup bobbins are shown in the table below. SUMIKASUPER LCP meets these requirements, thus can be considered as a material suitable for the manufacture of optical pickup bobbins.

Requirements Reasons of the Requirements Characteristics of SUMIKASUPER LCP
Compact size and low weight For power saving and high sensitivity
  • Low specific gravity
  • A moldability that enables precision molding
Reading signals accurately If resonation occurs at less than the operating frequency (-20kHz), the signal can not be read. The resonant frequency of low specific gravity and high elastic modulus material is high.
  • High rigidity (Flexural Modulus at a thickness of 0.5mm = approximately 30 GPa)
  • Low specific gravity
Low cost Can be mass-produced through injection molding.
As dip soldering can be performed during the assembly process (350- 400 deg C) x several seconds), the process of inserting metal terminals is no longer required as cost.
  • A moldability that enables precision molding
  • Resistance to heat from dip soldering

Grades for Usage in Optical Pickup Bobbins

SUMIKASUPER LCP grades that possess the above required properties for use in optical pickup bobbins, are as follows. E5006L, one of the standard grades, is the most suitable grade for usage in optical pickup bobbins. And, E5504S is suitable for many high performance DVD recorders and Blu-Ray applicaions due to its high longitudinal/side rigidity and low specific gravity. In addition, E5008L is recommended for CD-DA (audio) applications and CD-ROM drives.

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