[AEE] Koito Shows Off LED Headlight of New Prius

May 22, 2009
Kouji Kariatsumari, Nikkei Electronics
The low beam headlight for the new "Prius"
The low beam headlight for the new "Prius"
[Click to enlarge image]
Trends in power consumption of LED headlights
Trends in power consumption of LED headlights
[Click to enlarge image]

Koito Seisakusho Co Ltd exhibited an LED headlight used in Toyota Corp's new Prius at Automotive Engineering Exposition 2009, which is taking place from May 20 to 22, 2009, at Pacifico Yokohama in Yokohama City, Japan.

The LED headlight for the new Prius is a low beam assembly and composed of a double projector unit for irradiating a focused beam and a unit for emitting a diffused beam. Both units use white LED modules.

The LED module is manufactured by Nichia Kagaku Kogyo KK and consists of four elements. The module is also used in the LED headlight of the "RX450h" released by Toyota in April 2009, according to Koito Seisakusho.

The company mounted LED headlights for the first time in the world on Toyota's "Lexus LS600h" in May 2007. At that time, five LED modules were needed for the headlight. This time, the number of LED modules was reduced to three for the LED headlight on the new Prius because of the improved luminance efficiency of the LED.

Two headlights mounted on the new Prius consume 66W of electricity, which was reduced by slightly more than 30% compared with 100W consumed by the headlights of the LS600h, Koito Seisakusho said.

The cost of the new headlight was cut by simplifying its structure, in addition to using three LED modules instead of five. However, the cost is still higher than that of HID (high intensity discharge) headlights, the company said.

Koito Seisakusho expects that the adoption of LED headlights will be accelerated when the luminance efficiency of white LED improves and only two LED modules are required for a low beam headlight.