[Breaking Down Wooo UT] '4 Sheets' in Ultrathin Backlight [Part 5]

Dec 26, 2007
Nikkei Electronics Breakdown Team
Although Hitachi explained the panel module's thickness was 20mm, we could not figure out what part of the module Hitachi was indicating. The thickness of the part in the photo was 21.76mm.
Although Hitachi explained the panel module's thickness was 20mm, we could not figure out what part of the module Hitachi was indicating. The thickness of the part in the photo was 21.76mm.
[Click to enlarge image]
A 32-inch LCD panel appeared.
A 32-inch LCD panel appeared.
[Click to enlarge image]
Under the LCD panel were a group of optical sheets.
Under the LCD panel were a group of optical sheets.
[Click to enlarge image]
The optical sheets consisted of four sheets and a diffuser panel under them.
The optical sheets consisted of four sheets and a diffuser panel under them.
[Click to enlarge image]

The Nikkei Electronics Breakdown Team finished its analysis of the ultrathin power board, which was the key to the latest Wooo UT.

To tell the truth, one more component holds the key to the slimness of the display, which is only 35mm thick. As you can see, it is the backlight system that Hitachi described as being about 1/2 as thick compared with the backlight mounted on its existing LCD TV products.

We had a long way to go before reaching the backlight unit. First, we removed a variety of substrates tidily mounted on the rear side of the LCD panel module. As we detached a bezel around the LCD panel module, a 32-inch LCD panel emerged. Six units of source driver ICs were packaged using TAB (tape-automated bonding).

Being impressed with the drive circuit board on the side of the panel, which was so small that it could fit in the slim panel module, we removed the LCD panel. Then a backlight unit finally showed up. All we could see were optical sheets.

Although being intrigued with the light source behind these optical sheets, we decided to confirm their composition first. We removed the bezel holding the backlight unit and then removed the optical sheets.

"There are four sheets," murmured a participating engineer from a backlight manufacturer.

The optical sheets taken out from the backlight unit consisted of a diffuser panel with a thickness of about 2mm and four sheets located on the diffuser.

"Normally, two or three sheets are mounted on a diffuser," the engineer said before analyzing the reason why Hitachi used four optical sheets this time, as well as each sheet's function.