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  • Writer's pictureTruly Semiconductors

TFT-LCD glass substrate production factory generations


Introduction
In today’s electronic devices sporting a coloured display, chances are that you are looking at a TFT (thin-film transistor) LCD. TFT is an active-matrix display technology that allows pixels to be switched on and off quicker than the passive-matrix technology displays thanks to having a transistor for each pixel.
A TFT LCD manufacturing plant is classified by generation lines. Truly currently has a 2.5 generation, a 4.5 generation and two 5 generation TFT lines. But what do different generations mean and what benefits do each of them offer? Should you always aim to have your project’s TFT panels come from a bigger generation line?

Different generation lines
The key difference between the different generation lines lies in the size of the substrate glass or mother glass. The mother glass is the largest possible size of a glass that the generation of the factory can manufacture before getting scribed down to the desired panel size that we have on our devices. Given a fixed panel size, the bigger the generation the plant is, the more panels that can be cut from the mother glass where productivity and efficiency can be found.
It also means that bigger generation factories are necessary for bigger size displays such as those used on televisions and outdoor advertising signage.
Mother glass sizes
Below we look at the comparison of the mother glass size of the generation lines that Truly has.

Length (mm)

Width (mm)

GEN 2.5

370

470

GEN 4.5

730

920

GEN 5

1100

1250

GEN 5

1100

1300


The pros and cons
Does a bigger generation line mean a better fit for your project? Below we compare the pros and cons.

GEN 2.5

GEN 5

Pros

  • Lower NRE for customised designs

  • Lower MOQ for customised designs

  • Possibilities for high mix low volume


Pros
  • Better productivity hence cost

  • Ability to cater to bigger size designs

  • Better suited for current consumer market trend for bigger displays

Cons

  • Low panel output

  • Higher cost

  • Limited choice of sizes


Cons
  • Longer development time

  • Higher NRE for customised designs

  • Higher MOQ depending on output panel size


Conclusion​​

Depending on the size of the display your device may integrate, it may not be that straightforward to tool your design in a bigger generation line if your overall consumption volume does not meet the manufacturer’s minimum input of substrate glasses.
At Truly, we will advise the best solution based on the combined elements of the project details taking into account size, shape, annual quantities and display technologies.
We will also recommend dimensions to fully utilise the substrate glass to reduce wastage and improve productivity.
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