KOITO and DENSO Develop World's First Mercury-Free High-Intensity Discharge Headlamp System

Provides Bright Light and Long Bulb Life Without Harmful Environmental Effects of Mercury

TOKYO, July 27 -- KOITO Manufacturing Co., Ltd. and DENSO Corporation have developed, along with Toyota Motor Corporation and Royal Philips Electronics, the world's first mercury-free high intensity discharge (HID) headlamp system. This system completely eliminates mercury from discharge lamps (bulbs). The HID headlamp system is installed on the Toyota Porte, launched this month in Japan.

The HID headlamp system has a newly developed mercury-free discharge bulb, as well as a controller (ballast) that controls lighting of the discharge bulb. KOITO and Philips developed the mercury-free discharge bulb using a mercury substitute. KOITO and DENSO developed the ballast for lighting the mercury-free discharge bulb. Together, these developments led to the world's first mercury-free HID headlamp system that provides bright lighting and long bulb life, equal to the conventional HID headlamp system.

"In 2003, about 20 percent of new vehicles had the HID discharge system in Japan," said Mikio Tsuruta, director, General Affairs Department of KOITO Manufacturing Co., Ltd. "But we expect our mercury-free HID discharge system will expand the HID system share worldwide."

In addition to adopting the mercury substitute for the bulb, the bulb tube design was changed to maintain the long bulb life.

To control the lighting of the newly developed mercury-free discharge bulb, the ballast was improved to apply increased initial operating wattage and operating current to the bulb.

"Our ballast achieves an approximate 50 percent reduction in volume and 25 percent weight reduction over conventional ballasts, despite its increased initial operating wattage and operating current," said Hiromi Tokuda, managing officer of the Powertrain Control Systems Business Group, DENSO Corporation. "We achieved these reductions by increasing the switching frequency of the DC- DC converter contained in the ballast and enhancing the heat resistance of the ballast."

KOITO Manufacturing Co., Ltd., headquartered in Minato-ku, Tokyo, Japan, is a leading company of car lighting technology. It is the global supplier of automobile lighting equipment with an overseas network of 12 production bases in eight countries. As of March 31, 2004, the number of employees (KOITO Group) was 13,000 and consolidated global sales was 334,254 million yen. Please access http://www.koito.co.jp/ for more details.

DENSO Corporation, headquartered in Kariya, Aichi prefecture, Japan, is a global supplier of advanced technology, systems and components. Its customers include all the world's major carmakers. Worldwide, the company employs 95,000 people in 31 countries and regions, including Japan. Consolidated global sales for the fiscal year ended March 31, 2004 totaled US$24.2 billion. DENSO common stock is traded on the Tokyo, Osaka and Nagoya stock exchanges. For more information, go to http://www.globaldenso.com/ .

Southfield, Mich.-based DENSO International America, Inc. is DENSO's North American headquarters. In the Americas (North, Central and South America), DENSO employs 14,000 people at 32 companies with consolidated sales totaling US$5.3 billion for the above fiscal year.