AC plasma tile screen brief technical description.

AC plasma tile screens designed by “Polyscreen – S Company” are manufactured by “PDP Company”. (Both companies are members of “Mercury Electronics Group” Holding).

Tile screen contains up to 768 x 576 color pixels, corresponding to native resolution of PAL/SECAM TV standards and is very close to SVGA computer monitor resolution. Pixel size is about 3 mm, which gives image size of up to 2.4 x 1.8 m (3 m diagonal). Screen contains up to 12 x 9 AC plasma modules, each containing 64 x 64 color pixels. Total thickness of the screen is 120 mm. At the bottom of the screen is a compartment (which can hardly be seen on the photo) of 30 cm high, containing 6 power supplies, mains outlets, and a screen optical link controller. A PC computer, containing two custom boards of TV/RGB controller and PCI optical link controller, drives the screen.

Screen brightness is 350 cd/m². This is not a spot brightness, as usually mentioned for plasma TVs, but total area brightness. Maximum number of levels is 256 per each R, G and B, which gives total number of colors about 16 000 000. Screen can display composite TV signal in PAL, SECAM or NTSC standards, or a real time copy of computer picture in SVGA standard, taken from computer video adapter RGB connector, which eliminates the need in special software.

Total screen weight is slightly more than 300 kg. Screen construction allows “front access” for servicing. This means that the screen can be hanged on the wall.

Screen electronics consists of 5 types of single board systems. These are:

·        PDP module electronics;

·        screen optical link controller;

·        PCI optical link controller;

·        TV/RGB controller;

·        primary power supply.

PDP module electronics.

This is a 193 x 193 mm board (the same size as plasma panel) containing:

·        secondary power supply;

·        driving logic circuitry with memory buffer;

·        high voltage drivers.

Secondary power supply is fed with 180 V DC from primary power supply and generates various voltages, necessary for module operation.

Driving logic circuitry with memory buffer is connected with screen optical link controlled by 10Mb twisted pair. It gets appropriate data from the PC, stores frames in internal buffer and generates all the control waveforms to drive the panel and to display current frame.

High voltage drivers convert logic waveforms to particular high voltages, being applied to the plasma panel electrodes through flexible printed cables.

Each module consumes 44 W at full white.

Screen optical link controller.

This is approximately 400 x 280 mm board, residing in bottom compartment of the screen and containing:

·        Optical link interface;

·        Nine stripe controllers with memory buffers;

·        One hundred and eight 10 Mb twisted pair module controllers.

Optical link interface is driven by PCI optical link controller in full duplex mode with 1.2 Gbd data rate. It receives live video in digital form and demultiplexes it to 9 stripe controllers, each for one row of modules.

Stripe controller buffers data stream allowing to resend corrupted packages by twisted pair.

Twisted pair module controllers with optical decoupling communicate with individual modules.

PCI optical link controller.

This is a board in PCI format, installed in personal computer.

The board receives live TV in digital form, buffers it, makes necessary processing and sends it to screen controller through 1.2 Gb optical link. Board buffer can also be accessed from PCI bus, making possible direct image programming from computer. The board performs various graphics and color effects over the live image.

TV/RGB controller.

This is a half size ISA board, digitizing and processing composite TV signal in PAL, SECAM or NTSC standards and SVGA RGB signal from computer video adapter. The board controls brightness, contrast, hue, phase and other parameters of the signal. It also performs arbitrary downscaling of live image with various interpolation techniques. Processed signal is transferred to PCI optical link, controlled through custom 24 bit digital video bus.

Primary power supply.

There are six power supplies residing in the bottom compartment of the screen each 65 x 190 x 280mm. One per two columns of modules.

Power supplies implementing power factor correction are connected to 220 V mains and generate 1 KW of 180 V DC each.

The screen described above is a full size screen. At the moment we are also manufacturing reduced size screens with resolution of 640 x 512 pixels, composed of 10 x 8 modules, which gives image size of about 2 x 1.6 m. Such resolution is native for NTSC TV standard and VGA computer monitor standard, although PAL/SECAM TV picture can also be displayed with appropriate scaling, performed in TV/RGB board. This screen employs the same electronics and has similar characteristics to full size version, but due to smaller size is about 30% cheaper.

We also plan to design and manufacture 6mm pixel AC plasma screens with the size of up to 4.8 x 3.6 m.