1. How many types of LCD interfaces are there?

There are two main interfaces: LVDS and CMOS/TTL interfaces.

2. What is the difference between LCM and LCD?

LCD means liquid crystal display, LCM means liquid crystal display module (and components)

3. What is bias voltage?

STN liquid crystals generally require bias voltage and operating voltage. Changing the bias voltage can change the contrast and viewing angle.

4. Will violating the order of power-on have the same consequences for all display effects?

From time to time, different displays have different sensitivities to the power-up sequence.

5. How can my interface move a longer distance (about 10M)?

In order to drive the liquid crystal over a long distance, there are some differential drive methods that can be recommended. Two common differential technologies are low-voltage differential signaling LVDS and step-minimized differential signaling TMDS. You only need to use a professional sending/receiving chip to transmit the signal.

6. In order to avoid signal lock-up, when considering the power-on sequence of the liquid crystal module, is LP or CLK the most critical? Or do we need to consider it together?

In order to avoid locking, the most important thing is to remember "do not input any signal before VCC." All the signals are the same, including the scan control pin, and each signal must comply with the timing requirements.

7. What will happen to the LCD display at low temperature?

At low temperature, the viscosity of liquid crystal will become smaller and the response time will be longer. For TFT display, each point of it is directly driven by a transistor, and the impact is relatively small. But for STN, the response time at 0°C will reach 4 seconds

8. Can I supply 5V to a 3.3V-only display module?

It is not possible, there will be a risk of locking

9. When the operating temperature is higher than the temperature specified by the LCD, what will happen to the display?

When the operating temperature is higher than the specified temperature of the LCD, the response time of the display will be shortened and the contrast will be affected. The noise of some ICs will also increase, the DC-DC conversion will drift, and the polarizer will also be affected.

10. When the working temperature is lower than the temperature specified by the LCD, what will happen to the display?

When the operating temperature is lower than the specified temperature of the LCD, the display time will be slower, the contrast will be affected, the life of the cold cathode backlight tube will be shortened sharply, and the backlight may not be turned on.

11. Will the LCD emit harmful rays?

LCD does not emit any rays. But it has a low-frequency electrostatic field, and the backlight needs a voltage of about 50KHz to work.

12. The STN shows that some parts are brighter than other areas, why is this?

It should be caused by heat, such as: backlight and sunlight.

13. Will the front surface of the LCD be easily scratched?

The hardness of the front surface of the LCD is 3H, which is very easy to be scratched by some sharp tools.

14. If a certain pressure is applied to the surface of the LCD, will the LCD be easily damaged?

This should be avoided, although it is not easy to damage the LCD, but overvoltage will definitely damage the LCD.

15. How to measure brightness?

Luminance was measured in a completely white state 30 minutes after the backlight was turned on.

16. What is the viewing angle of the LCD?

The viewing angle of LCD is generally left-right symmetric, up-down asymmetric. The viewing angle of the passive matrix (STN type) display is smaller, and the viewing angle of the TFT liquid crystal is larger. Now the wide viewing angle technology has achieved a viewing angle of 170 degrees from top to bottom, left, and right, and you need to read the manual for details.

17. If I do a drop test, the most easily damaged part of the LCD is that part

When doing a drop test on an LCD, the cold cathode lamp is the most likely to be damaged, and then the edge of the LCD is prone to cracks.