Basics Knowledge about TFT Display You Need to Know

March 21, 2023
Latest company news about Basics Knowledge about TFT Display You Need to Know

Basic parameters of TFT LCD display

 

  • Display size

 

The display size of the TFT LCD liquid crystal display refers to the diagonal length of the actual visible area, and the unit is inches, referred to as inches (1 inch = 2.54 cm).

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Figure 1. Different display screen sizes

 

  • Aspect ratio

 

The aspect ratio is the ratio of the length and width of the visible area of the TFT LCD liquid crystal display, also called the screen ratio.

 

The aspect ratios of TFT LCD display are mainly 4:3, 5:4, 16:10, and 16:9. The ratio of 16:9 is closer to the golden ratio, which is more comfortable for human eyes to watch.

 

In the design of TFT LCD module, H (Horizontal) is generally used to indicate the length, and V (Vertical) is used to indicate the width.

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Figure 2. TFT LCD aspect ratio

 

  • Active area (AA)

 

AA refers to the total area that can be displayed on the TFT LCD display.

 

Through the display size and aspect ratio of the liquid crystal display, the specific length and width of the effective display area can be calculated by using the Pythagorean law.

 

It commonly used butt wire size (inch) representation, as shown in the figure below for a 7-inch TFT LCD display.

 

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Figure 3. TFT LCD active area

 

  • Resolution

 

Resolution is a measure of image clarity.

 

Usually it is measured by the number of horizontal and vertical pixels, expressed in the form of horizontal pixels x vertical pixels, such as 1024 x 768 resolution, where 1024 represents the number of pixels displayed in the horizontal direction of the effective display area, and 768 indicates the number of pixels displayed in the vertical direction.

 

In a fixed plane, the higher the resolution, the more detailed the image.

 

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Figure 4. Display resolution

 

  • Pixel pitch

 

The pixel pitch is the distance between two adjacent pixels in the effective display area of the TFT LCD display, that is, the minimum length of the pixel repeating unit.

 

The pitch of the TFT LCD display is fixed, and the calculation method of the pitch is the value obtained by dividing the panel size by the resolution.

 

The fineness of the picture is determined by the pixel pitch, the smaller the pixel pitch, the finer the picture.

 

A more accurate index to reflect the fineness of the picture is the PPI (Pixel Per Inch) value or DPI (Dots Per Inch) value, which is the number of pixels in a unit size.

 

High-definition TFT LCD with high PPI value.

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Figure 5.Pixel pitch

 

  • Power consumption

 

The power consumption of the TFT LCD display is mainly the power consumption of the backlight source, accounting for about 90%.

The focus of future development of TFT LCD display is to reduce power consumption.

 

  • Life span

 

The service life of the TFT LCD liquid crystal display mainly depends on the life of the illuminator (backlight), and the unit is hours (hrs).

 

In general, there is no problem with the use of TFT LCD display for tens of thousands of hours. If it is used for 5 hours a day, it can be used for about 10 years.

 

The service life of TFT LCD is also called Mean Time Between Failures (MTBF), which is calculated based on high temperature and high humidity operation experiments.