Panasonic's Room Light Automatically Changes Brightness to Save Power

Jan 29, 2009
Masaru Yoshida, Nikkei Electronics
The "Auto-eco Light-control Twin Pa," a home-use lamp equipped with a luminance sensor
The "Auto-eco Light-control Twin Pa," a home-use lamp equipped with a luminance sensor
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The sensor measures the luminance at a frequency of once per second. The green LED lights up when the sensor is activated.
The sensor measures the luminance at a frequency of once per second. The green LED lights up when the sensor is activated.
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The light installed in the ceiling of a room
The light installed in the ceiling of a room
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Panasonic Corp will release a home-use fluorescent lamp that automatically adjusts its light levels in accordance with the luminance in a room March 1, 2009, in Japan.

The "Auto-eco Light-control Twin Pa," equipped with a luminance sensor, detects the brightness in an area of 3m diameter directly below the lamp (when the ceiling height is about 2.4m) and controls the light output so that the luminance in the room is maintained constant.

"This is the industry's first home-use lighting equipment whose brightness is automatically adjusted by a sensor," Panasonic said.

Many households keep the living room light on even in the daytime. So, the product is intended to reduce power consumption in the daytime by making the most of light from windows. In the one-week experiment conducted by Panasonic in December 2008, the power consumption could be reduced by about 60%.

The product comes in two models, the "HHFZ4320" (89W) and the "HHFZ4220" (74W). There is no suggested retail price, but the expected street prices of them are ¥35,000 (approx US$389) and ¥32,000, respectively.

To be more precise, the luminance sensor measures the brightness of the floor directly below the lamp at a frequency of once per second. And it controls the light output in the range of 10 to 100% (in 65 increments) based on the average brightness during a ten-second period.

The brightness can be set at "100%," "70%" or "50%" by users. The speed of dimming and brightening was optimized so that users do not notice them. Also, it features a function to automatically correct the sensing range of the sensor when the light is initially installed because the degree of reflection varies depending on floor color.

Panasonic aims to sell 200,000 units per year and to incorporate the automatic dimming function in 10% of the Twin Pa Series products.