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The Ultimate Guide to LCD PCB Interface

LCDs are a great medium to watch fun movies and TV shows. Do you ever wonder what makes these LCDs so special? How do they perform as they do? Sit back and relax as we are going to discuss this in detail for you in this post. 

As you might know, LCD means liquid crystal display. Now all the LCDs work with some important components. These are microprocessors, aka microcontrollers. These are responsible for maintaining the brightness of all the pixels of LCDs. 

The color that you see on your LCD is due to these pixels. Now, there must be some kind of communication between these components and the LCD itself. Yes, this is called an interface. Let’s start discussing the LCD interface and its types in detail without keeping you waiting. 

What is an LCD PCB Interface?

 The LCD interface is a bridge between the display system and the processor of LCDs. Now this interface is always present on the chip of these LCDs. An interface will generate the image on the screen for you. 

There is not just one type of LCD interface available. Different LCDs use specific interfaces. Never heard of them yet? Let’s learn about them below! 

Types of LCD PCB Interface 

LCD display control PCB
LCD display control PCB

· Serial Peripheral Interface (SPI)

The SPI is like a data bus that contains different sets of data in it. The role of SPI is to join the two junctions which transmit data during the displaying. Now this interface uses a special signal clock. 

A signal clock is responsible for commanding the SPI to process this data at an accurate time. Edge is another term that you need to know to understand SPI better. Any change in the display is an edge. Now this edge can be anything. 

A sudden surge or loss of current or voltage is an edge as well. Another major part that contributes to this process is the chip select, aka slave select. The role of this part is to trigger the SPI for sending and receiving important data.

 Not only this, you can use chip select to only wake desired parts if needed. There are some important applications of SPI among LCDs. Here are a few:

  • Beneficial for graphic LCDs
  • Works best for character and digit LCDs
  • Different minute TFT LCDs use SPI 

· Inter-Integrated Circuit Interface (I²C)

It is one of the main types of serial interfaces. It appears to be similar to the former type of interface. However, this interface is a bit different from normal SPI. In terms of integration, it never works with the slave select, unlike SPI.

 For this type of interface, addressing is a method that prevents this mess. It helps in selecting an appropriate slave for smooth communication. A definite set of data is important for this purpose. 

The process of slave selection normally starts after the initiation of the first bit. Due to this reason, the signal that carries the output interacts with all the salve selects that are active. Now only these active slave selects interacting with the output will receive a specific message.

 Another process called “read and write” ensures a particular timeframe in which the master sends and receives data from the selected slaves. 

There are some similarities between these SPI and I²C interfaces that are important to consider. These are: 

  • Similar slave select/chip select
  • Similar signal clock attributes
  • Similar master 

· MCU Parallel Interface

The MCU interface is another type used in several LCDs. It is less complex since it can read and write data. The data is present on the internal layer or the storage of the device since this interface gives you enough storage to keep your data.

 You can easily store your videos, pictures, and documents with the help of a parallel interface. It uses different bits of data channels for signaling. However, RAM is important to make sure the display is working properly. There are some useful applications of parallel interfaces. These include:

  • Graphic LCDs
  • TFT LCDs
  • Character LCDs

LCD PCB Interface for the Large Display 

FULL PCB MANUFACTURING Quote

1. LVDS interface

LVDS is a type of differential signaling but with low voltage. It is the best possible interface type for giant LCDs. In case you want your LCD to consume less voltage and process data quickly, there is nothing better than an LVDS interface. 

It allows smooth suppression of electrical charges from one wire to the other. Now this is important for wireless systems, and LVDS makes sure of it. There is a circuit that has to inspect the changes in voltages that occur within two wires.

  There are some reasons for their wide acceptance for ensuring the fine quality of many LCDs. These are:

  • LVDS are good with high bandwidth
  • Work with excellence for HD graphics
  • Promise quick frame rates 

Pros

  • Works with small voltage changes
    • Blocks the noise when needed
    • Offers minimum electromagnetic interference 
    • No need for external biasing while using LVDS
    • Beneficial for the clock, data, and control signals
    • Accurate for using large displays

Cons

  • LVDS is expensive to use 
    • Supports twisted cables only 
    • The jitter performance is not always up to the mark

2. RGB interface

RGB interfaces are responsible for creating unbreakable links between the color displays. There is a fixed amount of bits for red, green, and blue colors, which is 8. Now, this amount never changes in the clock of this interface. The total amount of bits for this process will be 24 for each clock. 

Pros

  • Cost-efficient to use
    • Never compromises on performance
    • Offers large bandwidth
    • Accurate for large LCDs

Cons

  • RGB interface only works with expensive connectors that can create further complications like accessibility issues
    • It produces electrical noise that is not appropriate for wireless environments

3. EDP interface

 An EDP interface is a result of the evolution of former types of interface used in the past. It is a beneficial interface that promises fine performance and sustains the quality of electronics. 

An EDP interface is for smaller electronics. These devices are portable as well, which fits the purpose of an EDP interface. Some crucial roles of an EDP interface include:

  • Acts as a bridge between video electronics and displaying devices
  • An EDP also supports USB in case it’s needed
  • Such an interface is useful for transferring data like audio, videos, and all sorts of data
  • It teams up with a third-party A/V interface to produce a 4K HD display

Pros

  • The EMI is low, which is beneficial for extra covering 
    • Has no parallel for its HD resolution, impressive frame rate, and color depth feature
    • Does not require connections, unlike other types of interfaces 
    • The size is much smaller than other cable types of the same size

Cons

  • It is not an affordable interface to use, which makes it less accessible 

4. Mobile Industry Processor -MIPI interface

It is another type of interface mainly used in the mobile sector. There are many mobile developers that rely on the MIPI interface for developing smartphones. The method of signaling for this interface is similar to LVDS.

 The data lines and clock are important components of this interface. The best part about this interface is that it consumes less power and works with fast-paced control. It receives data from the display system impressively at low rates only.  

Pros

  • Useful only for the camera display system
    • Rectifies errors in real-time 
    • Can team up with different pixel systems
    • It is power-efficient, unlike other interfaces
    • Affordable for usage

Cons

  • Complexity
    • Suitable for smartphones only
    • Cannot work without an integrated board for transmissions

Efficient FPC LCD PCB – FPPC Units

lcd fpc

There are some factors that you need to know when determining LCD units. These factors will help you select the best fit of the interface as per your situation. We are going to have a deep look at these factors in this last section! 

· Energy-efficient

LCDs are now common to use with different types of devices today. LCDs undoubtedly save energy due to the integration of powerful interfaces. 

One noteworthy thing is the FPC type of display that consumes less energy. The FPC-based units are beneficial in increasing the contact between the components of LCDs. 

· Easy to clean

Another factor that makes FPC beneficial to use is that such a system is easy to clean. Now these connectors function with a special cable that connects with a conductive adhesive. Most of the FPCs are made of silicone. It means you can clean these silicone conductors completely with a brush. Make sure to handle them with care while cleaning to protect them from possible damage. 

The alternatives for cleaning these connectors include soft fabrics and spraying water to remove little fragments and debris. Do not leave any remains on the connector to ensure quality performance. Never use cleaning equipment containing detergents, as these are not appropriate for your LCD.

· Easy to connect

The FPCs are easy to connect as well. It means they consume less time for the assembly. You can easily connect critical panels with PCBs with the help of such connectors. Also, FCPs are important for bulky devices used in different domains. These include industrial machinery, consumer electronics, printing devices, and smartphones. 

· GPIO pins

These pins combine the sensors with the display system of your LCD. You can use LCD’s original connectors, but using additional connectors like FPC makes you assemble it fastly. 

Wrap Up!

Now you can easily select the best interface for your LCD. In this post, we have discussed the drawbacks of each interface as well. It will help you in making a perfect choice for interfaces that will serve well in the long run. 

 

 

 

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