LED backlight TV: clear image blur the future

In the CD just launched, the industry recognized CD in terms of sound quality is the most eye-catching advantages of high level of silence. Between the notes, CD doesn't hiss, and it doesn't make any noise. A recent similar progress is Dolby (Dolby) prototype, exhibited in the New York office, a day before the Lab Corp and Italy high-end home theater manufacturer SIM2Multimedia company jointly developed and this time, the industry's most impressive is the LCD screen close to black performance.

Dolby showed some images in the prototype display, as in the dark background of the realistic Lily in the night; in the streets of Tokyo to display bright dazzling lights (from the movie "speed and passion: Tokyo drift" a car chase scene); in the dark sky slowly now a plurality of faint grayish clouds.

In this presentation, SIM2 runs the Dolby lab's proprietary image processing algorithms on the PC to adjust the backlight and LCD crystals. SIM2 is expected in the next upgrade will use Xilinx's Virtex-4SXFPGA chipset to deal with this high dynamic range (HDR) algorithm, Dolby has approved the program at the end of last year.

Unlike the traditional LCD display, which is limited to 450 to 650cd/m2, Dolby laboratories claims that the SIM2 prototype screen has a brightness of more than 4000cd/m2.

Local dimming

When asked about Dolby's HDR and has been listed on the LCD TV LED backlight based on the difference of the Chinnock, said: "Dolby can make local dimming of the individual LED, which is much higher than other companies can reach the level of. In addition, the details of the local dimming algorithm are more complex and the brightness level is much higher. All in all, he says, "this is a very powerful local dimming technology. "

At present, the electronic industry has recognized the shortcomings of LCD, such as motion blur and poor color reproduction. Dolby, director of the imaging technology business line BharathRajagopalan said the contrast is the Achilles heel of LCDTV. Black is not black. Small dynamic range to the color fidelity has serious adverse effects. He said. Because it can not completely cut off the backlight, the current LCD screen even in the "off" state, the screen is not pure black.

The traditional solution is the "global dimming" - for the main image of the dark dimming the entire backlight, the light based image is the whole backlight dimming. However, because most of the brightness of the image in the middle level, which makes the global dimming of the image quality and static contrast is not improved.

HDR technology is a solution to the problem of the Dolby laboratory, which uses the local dimming technology to achieve better contrast and brightness LCD tv.

Local dimming contains two key points. Rajagopalan explains. First of all, unlike most of the CCFL tube (cold cathode fluorescent tube) as a backlight, can only adjust the entire LCD brightness of the practice, local dimming can be used to adjust the local LED and other solid-state light source. Secondly, the local dimming using the Dolby laboratory developed in the space and time on two levels of image processing algorithms, Rajagopalan said.

The backlight can be divided into several regions, each region can be adjusted independently according to the image brightness of the corresponding part. Backlight can be adjusted independently of the area, the better the overall contrast.

Although the Dolby laboratory early at the beginning of this year's International Consumer Electronics Show (CES) released its HDR technology, but the New York show the many local can control LED for LCD backlight, the real quality really let people see the technology. Dolby lab in 46 inch LCD panel backlight design uses a LED of 1838, in order to fully demonstrate its high dynamic range (HDR) technology potential.

Figure 1: Dolby's local dimming technology: improving static and dynamic contrast by adjusting individual LED or a set of LED

Dolby into the video field?

Dolby lab's most famous achievement is the digital audio technology of the, which is currently being used in every digital TV and DVD player. Today, Dolby lab will rely on HDR technology into the consumer video market.

Rajagopalan insisted that Dolby is not a novice in the field of video services. Prior to the creation of the Dolby lab in 1965, its founder, RayDolby, was engaged in the field of video in Ampex in 1950s. "Video is his passion. "Rajagopalan says.

In the field of professional video, Dolby has been very active in digital cinema, we have developed the 3D theater technology. "

However, Dolby's HDR technology is not the invention of Dolby. A year ago, Dolby acquired the Canadian BrightSide company to obtain HDR technology, then, HDR is still in the development stage of BrightSide imaging technology.

Rajagopalan said that even with HDR, Dolby's basic licensing business model will not change. Similar to Dolby's audio technology, Dolby will authorize HDR to OEM. "We will not be involved in the manufacture or sale of LCD TV business. He said.

In addition to licensing, Dolby will be associated with HDR related expertise to help OEM, Rajagopalan said. In addition, SIM2 will also provide LCD TV reference design using HDR technology. It is predicted that HDR technology LCD TV consumer spending will eventually use ASIC rather than FPGA to run the HDR algorithm. But Du