NITTO Around You

You who are watching a favorite movie with a DVD player now !
There may be some optics produced by Nitto Optical in it.

What are Optical Pickup Heads?

Optical Pickup Heads are optical components consisted of laser beam sources, optical receiving parts and precise mechanical parts. And they are used for playing and recording information from optical disks such as CD (compact disks) and DVD (digital versatile disks). In the past, a music recording on an LP was converted into a sound signal by a record needle. However, now, by palm-size, large capacity memory such as CD and DVD, a document, an image, a photograph, a picture, and various data are read out using laser beams. It is also possible to write (record) information into laser disks such as CD-R, CD-RW, DVD±R, and DVD±RW with laser beam.

Basic Structure for Optical Pickup Heads

The stitches of record needles were a size of approximately 0.5mm but in optical pickup heads, high-quality object lenses are used to focus a narrow beam of 1 micron. Ultra-precise optical parts supporting advanced technology are required to create a thin beam.

As shown in the figure, in optical pickup heads, laser beams emitted from internal laser diode reflect or transmit various optical components and arrive at an information surface (minute bit strings) of an optical disk. The laser beams that arrive at a laser disk returns to optical pickup heads. In the optical pick-up inside, the reflected beams are processed and converted into an automatic focus error detection signal, automatic tracking error detection signal and information data (an electrical signal).
Moreover, when a focus error signal and a tracking error signal are detected from reflected beams in optical pickup heads, focus and tracking adjustments are performed automatically. In this way, after automatic control was performed, laser beams of an optical pickup heads can read digital data signal recorded in a laser disk and can record (write) digital bit information on the laser disk information surface by laser beams.
A range of a focus error signal is ±1μm. A range of a tracking error signal is ±0.1μm. They are extremely ultra-precise.

An infrared semiconductor laser (laser diode) of wavelength 780nm is used for CD, a red laser of wavelength 650nm is used for DVD and a purple blue laser of wavelength 405nm is used for pickup heads for next-generation DVD such as Blu-ray Disc or HD DVD. (The shorter the wavelength becomes, one piece of disk can record and play more information.)
Therefore, optical disk drives, which are compatible with multiple standards, require the installation of multiple optical pickup heads and require optical pickup heads with high quality optical parts such as beam splitters and prisms that are compatible with multiple laser light sources (2 wavelengths, 3 wavelengths).

What is Nitto Optical producing?

NITTO OPTICAL contributes to optical pickup technology through manufacturing of these kinds of optical parts which are absolutely essential for optical pickup heads.