Hitachi Introduces Industry's First Red Laser Diodes Offering A Nearly Circular Beam With An Aspect Ratio of 1.2

Business Wire, June 26, 2001

Business Editors/High-Tech Writers

SAN JOSE, Calif.--(BUSINESS WIRE)--June 26, 2001

By Producing a More Uniform Light Pattern, the High-Efficiency

635-nm Laser Diodes Make It Easier to Design Laser Markers,

Optical Fiber Test Equipment and Other Lightwave Products

Hitachi Semiconductor (America) Inc. today announced the "MARU Beam" series(1) of red laser diodes, which produce a nearly circular light beam with an aspect ratio (beam height/beam width) of 1.2. This is an industry first for laser diodes in the 635-nanometer (nm) band wavelength.

"Hitachi is now able to achieve the operation current approximately 40% lower than the previous diodes," said Paul Patterson, Director of the wireless, lightwave and power business unit at Hitachi Semiconductor Inc. "These laser diodes are very efficient and make the process of designing lightwave products like laser markers and levelers much simpler. Our goal is to continue to develop higher output versions of MARU Beam devices and ultimately achieve a fully circular beam with the laser diodes."

Compared to traditional devices with elliptical light beams, the new laser diodes make it possible to simplify the beam-forming mechanism in laser levelers, line markers, and other products. Also, in lightwave test equipment, the rounder beam facilitates the connection to an optical fiber, for better testing.

Highly efficient series of laser diodes

The first MARU Beam products are five-milliwatt (mW) laser sources with the HL6335G series (9-millimeter package) and the HL6340MG series (5.6-millimeter package). The diodes in both series are highly efficient with an operating current for a 5-mW output at only twenty-five milliamps (mA). In portable products, this increased efficiency helps extend battery life. Anode-common and cathode-common versions are available in both device series.

Efficient devices use SRI and MQW structures

Hitachi achieved the new red laser diodes' exceptional performance by using a self-aligned refractive index (SRI) structure in combination with an optimized strained multi-quantum well (MQW) structure.

The SRI structure is a wave-path structure in which a parallel-direction block layer is formed at the time of crystal growth. The active layer of the laser diode is inserted in a clad layer for which there is a difference in refractive index. The perpendicular-direction clad layer and the parallel-direction block layer are formed simultaneously, so the width of each layer can be controlled precisely, ensuring a low aspect ratio.

In the MQW structure the active layer of the laser diode is a laminated structure comprising quantum well layers and barrier layers with a thickness of several nanometers. By regulating the composition of the quantum well layers that constitute the light-emitting area, and using a crystal with a smaller lattice constant than the substrate, tensile strain is introduced into the quantum well layers. The band structure varies due to this strain, resulting in two desirable design characteristics of a lower threshold current and higher slope efficiency.

Hitachi currently mass-produces a variety of 635-nm band wavelength laser diodes with optical outputs ranging from 3 to 35 mW. Future plans include higher output power versions of MARU Beam devices and the development of laser diodes with beams that are fully circular (1.0 aspect ratio).

(1): "MARU Beam" is a circular beam series product of Hitachi.

Pricing, Packaging and Availability

Laser Diode,        Package           Quantity  Price/Availability
635 nm, 5 mW   (anode common or
                cathode common)

  HL6335G          0.9 mm              10,000    $ 60.00/3Q 2001

  HL6340MG         0.6 mm              10,000    $ 85.00/3Q 2001

About Hitachi Semiconductor (America) Inc.

Hitachi Semiconductor (America) Inc., a subsidiary of Hitachi America, Ltd., supports the requirements of the North American marketplace with a broad range of standard and low-power semiconductor solutions. Offering some of the industry's most popular microcontrollers, microprocessors, memory components, and electro-optical components, among other semiconductor solutions, Hitachi provides chips to the world's leading device manufacturers within industrial, consumer and emerging market applications. Hitachi's substantial design engineering, research and development facilities in the United States help bring the world's best technology to U.S. customers. For more information, visit: www.hitachi.com/semiconductor.> Hitachi America, Ltd., a subsidiary of Hitachi, Ltd. (NYSE: HIT), markets and manufactures a broad range of electronics, computer systems and products, consumer electronics and semiconductors, and provides industrial equipment and services throughout North America. For more information, visit: www.hitachi.com.

Hitachi, Ltd., headquartered in Tokyo, Japan, is one of the world's leading global electronics companies, with fiscal 2000 (ended March 31, 2001) consolidated sales of 8,417 billion yen ($67.9 billion(2)). The company manufactures and markets a wide range of products, including computers, semiconductors, consumer products and power and industrial equipment. For more information on Hitachi, Ltd., please visit Hitachi's Web site at http://global.hitachi.com.