World's First Blue-Violet Laser Diode with a New Low-Noise Beam Structure

FOR IMMEDIATE RELEASE : 13.Mar.2002

	World's First Blue-Violet Laser Diode with a New Low-Noise Beam Structure - Ideal light source for advanced DVD systems -

	Tokyo, March 13, 2002--- SANYO has developed the world's first blue-violet laser diode with a new low-noise (stable) beam structure produced using ion implantation. The stable beam structure boasts lower noise, and current consumption achieving higher performance compared with conventional blue-violet laser diodes. This structure makes SANYO's blue-violet laser diode an optimum light source for large-capacity optical disc systems like advanced DVDs.

Main features

■	SANYO's original ion implantation technology has yielded the world's first blue-violet laser diode with a new stable beam structure that generates a low-noise beam.

■	The stable beam structure produces a vastly improved stable laser beam, which yields the low-noise, low-operating current characteristics that are required in a light source for next-generation large-capacity optical disc systems like advanced DVDs require.

■	The laser diode is easily mass produced because the stable beam structure reduces the number of fabrication steps while the top and bottom electrodes structure reduces chip size. ・ Related patents: 25 (including those pending)

Development background

Laser diodes are key components in the field of optical data processing devices. SANYO's aggressive efforts in this area led to the mass production and sales of AlGaAs (aluminum-gallium-arsenide) infrared and AlGaInP (aluminum-gallium-indium-phosphide) red laser diodes widely used in measuring instruments and a variety of optical data processing devices like CD and DVD optical disc systems.

In recent years, the field of optical disc systems has seen the development of next-generation large-capacity optical disc systems like advanced DVDs that can record more than two hours of digital high-definition images. The blue-violet laser diode made of InGaN (indium-gallium-nitride) that is used as a light source for reading signals recorded on the optical discs was the key to developing these systems. Naturally demand for the laser diode is expected to rise sharply as more large-capacity optical disc systems become available and become more widely used.

In order to realize a blue-violet laser diode SANYO has developed original crystal and device fabrication technologies over the years. Now these fundamental technologies have yielded the world's first low-noise beam, blue-violet laser diode with a new stable beam structure that lowered noise and current consumption for higher performance. This development can make large-capacity optical disc systems like advanced DVDs practical.

The Microelectronics Research Center in the Research and Development Headquarters at SANYO Electric Co., Ltd. will be in charge of development, while the LED Division in the Electronic Device Business Headquarters at Tottori SANYO Electric Co., Ltd. will be handling production and sales.

Features of the new technology

■	The new stable beam structure made by ion implantation significantly improves laser beam stability and yields the low-noise, low-operating current characteristics that the optical disc system requires.

■	The laser diode is easily mass-produced because the newly developed stable beam structure reduces the number of fabrication steps while the top and bottom electrodes structure reduces chip size.

Other features

■	Fundamental traverse mode The fundamental traverse mode generates a single stable beam which means the beam can be focused into a tiny spot using a simple optical system.

■	Package The package is compact at just 5.6 mm in diameter.

■	Polarity A positive (+) or negative (-) power supply can be selected.

■	Built-in photodiode for monitoring optical output A photodiode is installed to monitor optical output.

■	Applications The new laser diode is suitable for the next-generation large-capacity optical disc systems like advanced DVDs as well as for many types of measuring instruments.

Terminology

■	Blue-violet laser diode This is the light source used to read signals (pits) on discs in next-generation large-capacity optical disc systems. There is no way the size of beams from the infrared and red laser diodes now used in CDs and DVDs can be reduced to the size of a pit recorded on these discs in conventional optical systems. The shorter wavelength of the blue-violet laser diode however allows the beam to be focused into a reduced spot, and therefore is the key to next-generation large-capacity optical disc systems.

■	Stable beam structure The newly developed stable beam structure was produced using ion implantation. With mode control of the laser beam and current confinement, the implanted layer significantly improves laser beam stability and yields the low-noise, low-operating current characteristics that an optical disc system requires.

■	Ion implantation This technology uses a strong electric field to force ionized atoms into a semiconductor. It is mainly used in Si LSI production for doping impurities in semiconductors. The amount and depth of the atoms implanted into the semiconductor can be precisely controlled with consistent reproducibility.

■	Fundamental traverse mode This refers to a mode where distribution of light intensity in a laser beam forms a single peak.

Specifications
Case temperature: 25°C

Light output		5mW
Threshold current		40mA
Operating current		45mA
Lasing wavelength		405nm
Beam divergence	Parallel	8°
	Perpendicular	30°

Inquiries and data material requests

Microelectronics Research Center (Supervisor: Sawada), Research and Development Headquarters, SANYO Electric Co., Ltd.
1-18-13 Hashiridani, Hirakata, Osaka Prefecture 573-8534
Email : msawada@rd.sanyo.co.jp
Telephone : +81-72-841-1278
Facsimile : +81-72-841-1412