Panasonic to Launch 'Industry's Greenest' LED Light Bulbs

Sep 11, 2009
Masaru Yoshida, Nikkei Electronics
Panasonic's E26 LED light bulb
Panasonic's E26 LED light bulb
[Click to enlarge image]
From left to right: the dimmer-compatible 60W-equivalent E26 lamp, the dimmer-incompatible 60W-equivalent E26 lamp, the 40W-equivalent E26 lamp and the 40W-equivalent E17 lamp. The upper products emit daylight color light, and the lower products emit incandescent color light.
From left to right: the dimmer-compatible 60W-equivalent E26 lamp, the dimmer-incompatible 60W-equivalent E26 lamp, the 40W-equivalent E26 lamp and the 40W-equivalent E17 lamp. The upper products emit daylight color light, and the lower products emit incandescent color light.
[Click to enlarge image]

Panasonic Corp will release E26 and E17 LED light bulbs Oct 21, 2009, in Japan.

The company offers three types of E26 LED light bulbs. Their illuminances immediately below the bulbs are equivalent to those of 40W and 60W incandescent light bulbs. And there are two kinds of the 60W-equivalent models: One supports dimmers, and another does not.

The power consumptions of the 40W-equivalent model, the dimmer-incompatible 60W-equivalent model and the dimmer-compatible 60W-equivalent model are 4W, 6.9W and 7.6W, respectively.

The illuminance immediately below the E17 LED light bulb is equivalent to that of a 40W incandescent light bulb. It consumes power of 5.5W and supports dimmers.

The length and maximum outer diameter of the E17 light bulb are 72mm and 40mm, respectively, so it is slightly larger than a mini krypton bulb (length: 67mm, outer diameter: 35mm). According to Panasonic, it is the industry's first LED light bulb that can replace a mini krypton bulb.

Both the E26 and E17 LED light bulbs will be released in two models that emit incandescent color light (color temperature: 2,800K) and daylight color light (color temperature: 6,700K). There is no manufacturer's suggested retail price. But the prices of the dimmer-incompatible models and that of the dimmer-compatible models are expected to be about ¥4,000 (approx US$43.6) and 5,000, respectively.

High radiation performance, low weight achieved without fins

The combined efficiencies of the E26 LED light bulbs are 85lm/W for the 40W-equivalent model (daylight color light) and 82.6lm/W for the 60W-equivalent models (daylight color light). According to Panasonic, they are the industry's highest combined efficiencies.

To enhance luminance efficiency, the company made improvements to the heat dissipation structure. Specifically, to reduce the heat resistance of the LED package and the chassis, it closely attached the substrate mounted with the package to the aluminum chassis and applied alumite treatment to the surface of the chassis. The alumite treatment improved the emissivity by four to five times, according to the company.

Many of the chassis of competitors' products are equipped with fins to enhance radiation performance, but Panasonic's LED light bulbs have a flat surface.

"When light bulbs are attached to lighting equipment, natural convection cooling effects cannot be expected much," Panasonic said. "That's why we chose alumite treatment instead of fins."

The LED light bulbs without fins do not get dusty and tend to be low in weight, according to the company. The cylinder-shaped part of the chassis is formed by press working and as thin as 0.4mm. The masses of the E26 and E17 LED light bulbs are100g and 50g, respectively. In the case of the E26 light bulbs, they are about 40g lighter than competitors' products.

The LED chip is manufactured by Toyoda Gosei Co Ltd. The LED light bulbs have a single LED package containing multiple LED chips. Panasonic did not reveal the number of LED chips. It aims to sell 400,000 units in fiscal 2009.


Correction Notice: Because of a reporting error, we incorrectly used "°C" for the color temperatures of the light bulbs. In fact, "K" should be used as their unit.