Hitachi Ltd showcased prototypes of an LCD display and PDP TV that feature power-saving functions for reference at CEATEC JAPAN 2009.
The LCD display uses HCFLs (hot cathode fluorescent lamp) as its backlight source. And the screen of the PDP TV automatically turns black when the user looks away from it. Their release dates have not been decided yet. Sony Corp commercialized a similar product, "Bravia Eco HDTV," in January 2009 (See related article).
32-inch LCD panel with 2 HCFLs
The size of the LCD panel is 32 inches. HCFLs have a luminance efficiency higher than that of CCFLs (cold cathode fluorescent lamp), which are commonly used as backlight sources. By using HCFLs, Hitachi achieved a power consumption of less than 40W (31.2W in the demonstration).
The LCD panel is equipped with two HCFLs that were developed by Hitachi Lighting Ltd, Hitachi Media Electronics Co Ltd and Hitachi Advanced Digital Inc and whose diameter is 15.5mm.
The LCD panel is an IPS (in plane switching) type, and its resolution, luminance and drive frequency are 1,366 x 768, 310 to 350cd/m2 and 60Hz, respectively. The prototyped display measures 814 x 538 x 100mm.
PDP TV uses camera to recognize human face
The PDP TV was developed by mounting a camera on Hitachi's 42-inch PDP TV (model number: P-42-XP03) that is currently being mass-produced. Using the face recognition function of the camera, it determines whether the user is looking away.
When the TV judges that the user is not looking at the screen, it displays only the words, "Energy is being saved now," blacking out the other part of the screen. It takes at least three seconds to switch the screen though the switching speed can be changed. The audio is not turned off.
Sony's Bravia Eco HDTV detects human movements with an infrared sensor.
In addition, Hitachi exhibited an LCD TV with LED backlight. Its screen size and resolution are 42 inches and 1,920 x 1,080, respectively.
"It is as bright as CCFL-backlit products but consumes half the power," the company said.
The LCD TV applies local dimming to input signals. But the company declined to comment on the number, type (white/RGB) and layout (direct-lit/edge-lit) of LEDs. It aims to commercialize the LED-backlit LCD TV in 2010.