LCD TV Panels: A History Of Their Interface Technology

In the display industry, the consistent trend is to move toward higher-resolution displays. However, increasing the resolution results in increasing the overall data rate both from the host to the panel, and within the panel
itself. By the late 1990s, resolutions for LCD (liquid crystal display) panels were moving from VGA (video
graphics array) resolutions with a cumulative bandwidth requirement of slightly more than 300 Mbits/s to XGA (extended graphics array) resolutions that required 850 Mbits/s. In addition, UXGA (ultra extended graphics array) resolution and its 2-Gbit/s requirement loomed on the horizon. The increasing frequency was creating problems with the TTL interface between the host and the LCD panel. Power consumption was ballooning, electromagnetic interference (EMI) was on the rise, and larger connectors and cables were required to meet the expanding number of data lines.

In 1999, National Semiconductor released the Open Low-Voltage Differential-Signaling Display Interface, or OpenLDI specification, which serialized 22 TTL signals down to four differential pairs. Because the new interface was low swing (±400 mV versus several volts for TTL) and differential, the total power and EMI were significantly reduced. Also, as the total number of wires was reduced from 22 down to eight, the connectors and cabling shrank, saving system cost and improving the mechanical connection between the host and the panel. OpenLDI is now the de facto standard interface between the graphics controller
and the LCD panel in notebook computers.

Once the issues of the host-panel interface were solved, similar issues existed within the panel. For XGA resolutions, system designers were using a dual TTL bus with 36 data signals per bus. National Semiconductor used the success of LVDS and OpenLDI as a baseline for creating another open standard for the Reduced-Swing Differential-Signaling (RSDS) interface to solve intra-panel interface issues. The RSDS interface reduced the total number of wires from 72 (two 36-wide buses) to 20 (10 differential pairs). The voltage swings were ±200 mV differential, reducing both the power and the EMI of the panel.
Following the success of OpenLDI, RSDS technology has become the de facto standard for intra-panel interfaces for all notebook and monitor resolutions from XGA through UXGA.

LVDS and RSDS technologies accomplished the same end goal at two different points in the data flow. LVDS technology lowered the power, improved EMI, and reduced the wire count between the graphics controller and the LCD panel. RSDS technology provided the same benefits between the timing controller and the column drivers within the panel. More information on LVDS and RSDS technologies is available at www.national.com.

Credit: Craig Zajac | ED Online ID #8445 | July 19, 2004

7" Hannstar Panel, Model Name: HSD070IDW1-A10

HannStar Display model HSD070IDW1-A is a color active matrix thin film transistor (TFT) liquid crystal display (LCD) that uses amorphous silicon TFT as a switching device. This model is composed of a TFT LCD panel, a driving circuit and a back light system. This TFT LCD has a 7.0 (16:9) inch diagonally measured active display area with WVGA (800 horizontal by 480 vertical pixel) resolution.

 

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7" AUO Panel, Model Name: A070FW03 V4

 

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32" CMO Panel, Model Name: V315B6TY1-E01

V315B6TY1-E01 is a 31.5” TFT Liquid Crystal Display module with LED Backlight unit and 1ch-LVDS interface. This module supports 1366 x 768 WXGA(16:9 wide screen) format and can display 16.7M colors (6-bit+HI-FRC colors). The LED driver module for backlight is not built-in.

 

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32" AUO Panel, Model Name: T315HW05 V3

This specification applies to the 31.5 inch Color TFT-LCD Module T315HW05 V3. This LCD module has a TFT active matrix type liquid crystal panel 1,920x1,080 pixels, and diagonal size of 31.5 inch. This module supports 1,920x1080 mode. Each pixel is divided into Red, Green and Blue sub-pixels or dots which are arranged in vertical stripes. Gray scale or the brightness of the sub-pixel color is determined with a 8 -bit gray scale signal for each dot. The T315HW05 V3 has been designed to apply the 8-bit 2 channel LVDS interface method. It is intended to support displays where high brightness, wide viewing angle, high color saturation, and high color depth are very important.

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39" 4K Panel Module, Model Name: V390DK1 LS1

V390DK1-LS1 is a 39” TFT Liquid Crystal Display module with LED Backlight unit and 4ch-LVDS interface.This module supports 3840 x 2160 Quad Full HDTV format and can display true 1.07G colors (8-bit+FRC). The driving board module for backlight is built-in.

FEATURES
- High brightness 350 nits
- High contrast ratio 5000:1
- Fast response time Gray to Gray typical : 6.5 ms
- High color saturation NTSC 72%
- Quad Full HDTV (3840 x 2160 pixels) resolution, true HDTV format
- LVDS (Low Voltage Differential Signaling) interface
- Optimized response time for 100Hz/120Hz frame rate
- Viewing Angle : 176(H)/176(V) (CR>20) VA Technology
- Ultra wide viewing angle: Super MVA technology
- RoHs compliance
- T-con input frame rate : FHD 50/60Hz, FHD 100/120Hz or QFHD 24/30Hz
Output frame rate: QFHD 50/60Hz, QFHD 100/120Hz or QFHD 48/60Hz

 

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50" 4K Panel Module, Model Name: V500DK2 PS1

V500DK2-PS1 is a 50” TFT Liquid Crystal Display product with driver ICs and 4ch-LVDS interface. This product supports 3840 x 2160 QFHDTV format and can display true 1.07G colors (10bit color). The backlight unit is not built in.

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