TN, STN, HTN and FSTN are different types of liquid crystal display technology, and the main difference is that the arrangement and driving mode of liquid crystal molecules affect the display effect and application scenario. Here's how they differ:

1. TN (Twisted Nematic)

    Features：The liquid crystal molecules are arranged in a spiral, and when the voltage is applied, the molecules are rearranged to change the 

                        transmittance of light.

    Advantages: Low cost, fast response.

    Disadvantages: Narrow viewing Angle, general color performance.

    Applications: early liquid crystal display, electronic calculator, digital clock, etc.

2. STN (Super Twisted Nematic)

    Features: Liquid crystal molecular torsion Angle is larger (180°-270°), contrast and viewing Angle is better than TN.

    Advantages: High contrast, wide viewing Angle.

    Cons: Slow response, still limited color performance.

    Applications: Early mobile phone screens, PDAs, industrial equipment, etc.

3. HTN (High Twisted Nematic)

    Features: The liquid crystal molecular torsion Angle is between TN and STN (about 110°-130°), and the performance and cost are between the two.

    Advantages: Contrast and viewing Angle are better than TN, cost is lower than STN.

    Disadvantages: Color performance and response speed are average.

    Applications: Devices requiring moderate display performance, such as low-end industrial displays.

4. FSTN (Film Compensated Super Twisted Nematic)

    Features: On the basis of STN, compensation film is added to improve the viewing Angle and contrast, and the display effect is close to passive matrix LCD.

    Advantages: Wide viewing Angle, high contrast, good display effect.

    Disadvantages: Higher cost and slower response time.

    Applications: high-end industrial equipment, medical equipment, testing instruments, etc.

Sum up：

    TN: Low cost, fast response, but narrow viewing Angle, poor color.

    STN: Better contrast and viewing Angle than TN, but slow response and limited color.

    HTN: Performance and cost between TN and STN.

    FSTN: Wide viewing Angle, high contrast, good display effect, but high cost, slow response.