How Much Do You Know About LCD Display Module Interfaces?

When customizing LCD display modules, it is crucial to confirm the interface type, which holds significant importance. Otherwise, using an incorrect interface type with its corresponding parameters could lead to various consequences. These range from being unable to achieve the desired display content and area, to severe outcomes such as LCD screen burnout and direct disposal.

Therefore, when customizing LCD modules, it's essential to have a good understanding of the module's interface, confirming the interface type, pin sequence, and related parameters. Today, we will provide you with a brief overview of LCD interface classifications, focusing on LVDS and eDP interfaces.

 

The LCD screen interface refers to the connection between the controller and the LCD module. Through this interface, the controller can control parameters such as brightness, contrast, and color of the LCD module, thus achieving image display. Common LCD screen interfaces include TTL, LVDS, eDP, MIPI, etc.

Interface Classifications: Categorized by signal type: TTL/LVDS/eDP/MIPI Categorized by material: (for TFT-LCD) TFT-TN/TFT-IPS/TFT-VA Categorized by interface type: RGB mode, SPI mode, MDDI mode, VSYNC mode, DSI mode, MCU mode, etc.

 

When designing and using a screen, besides assessing whether the screen's active area (visible area), outer dimensions, and basic LCD parameters meet requirements, one must also select an LCD screen interface mode suitable for the host communication of the mainboard. The compatibility of the interface mode determines whether this LCD display can be used. Alternatively, HDMI, VGA, or DVI driver boards can be used to address this issue.

Currently, there are numerous commonly used LCD screen interfaces. It's crucial to ensure that the interface is compatible with the respective mainboard; otherwise, an additional driver board might be needed, affecting the overall structural design.

Different interface types have varying application scopes, typically categorized based on transmission rate and image quality requirements:

●MCU: Commonly used for displaying static images with low transmission speed requirements.

●RGB: Commonly used for mid-sized screens with moderate transmission speed requirements, suitable for displaying videos or animations, generally with resolutions lower than 800x600.

●LVDS: Commonly used for medium to large screens requiring high transmission speeds.

●MIPI: Commonly used for products with higher resolutions and transmission speed requirements, such as smartphones.

●eDP: Commonly used for products with relatively high transmission speed requirements, such as tablets, laptops, and all-in-one PCs.

In this article, we will introduce you to two commonly used interface types in the market: LVDS and eDP interfaces.

 

LVDS (Low Voltage Differential Signal) is characterized by its current-driven mode and voltage swing of 350mV loaded onto a 100Ω resistor. LVDS offers advantages such as high-speed transmission, low noise, low power consumption, and low voltage requirements.

 

The eDP (embedded DisplayPort) interface requires a simpler connector and fewer pins to transmit high-resolution signals. It can also achieve the simultaneous transmission of multiple data streams, resulting in a much higher transmission rate compared to LVDS. Its excellent EMI (electromagnetic interference) protection makes it suitable for applications with high EMI requirements and higher LCD screen resolutions. eDP is often referred to as the "new LVDS."

eDP is a fully digital interface based on the DisplayPort architecture and protocol. It can transmit high-resolution signals with a simpler connector and fewer pins. It consists of three main channels: the Main Link for audio and video transmission, the AUX channel, and the Hot Plug Detect (HPD).

eDP screens are connected through 0.3-0.5 mm pitch soldered flat cables. eDP channels can be classified into single-channel and dual-channel configurations, using 2, 3, 5, or 8 twisted pairs of wires. Common data rates include 1.62 Gbps per lane, 2.7 Gbps per lane, and 5.4 Gbps per lane.

Key features of eDP include its compatibility with DP protocol, suitability for chip-to-chip and screen-to-driver board connections, high-speed simultaneous data transmission, low electromagnetic interference, and its potential to replace traditional LVDS interfaces.

For example, a 1920x1200, 24-bit color LCD screen requires 20 pairs of data transmission lines when using LVDS, while only 4 pairs are needed for eDP. This demonstrates the clear advantage of eDP, especially in high-definition screens.

eDP offers high bandwidth, good integration, and simple product design, and has found broad applications in integrated display panels and image processors for laptops, tablets, smartphones, and other devices. With its scalability to support higher color depths, refresh rates, and display resolutions, eDP is rapidly becoming a mainstream interface.

 

If you need to purchase our TFT-LCD Module, you can contact us at sales@innoluxlcdpanel.com