Why do we prefer VA products for negative display in the development of segment code screens?

Often, in the early stage of development, engineers choose LCD screens for data visualization. Among them, for small household appliances and other products with digital displays, 7 segment  lcd screens are often the first choice. To ensure the overall harmony of the product, we usually determine the lcd display effect first.
Positive lcd display means that the pixel is transparent when there is no voltage and opaque when lit, resulting in a lcd display effect of black characters on a white background.
Negative lcd display means that the pixel is opaque when there is no voltage and transparent when lit, resulting in a display effect of white characters on a black background (usually with backlight).
However, the lcd display effect of different materials varies. TN/HTN lcd has a lower contrast ratio, with the black color not being deep enough and tending to be gray. Commonly, only the display effect at the 6 o'clock direction is good, while other angles may show color bias or white-out. The response speed is fast, making it suitable for simple digital and character lcd displays.
VA LCD 7 segment lcd have a high contrast ratio, with a deeper black color, resulting in a clearer display effect of white characters on a black background (VA is generally only used for negative lcd display).
The viewing angle is much better than TN lcd , approaching full viewing angle (>160°). The response speed is slightly slower than TN, but it is sufficient for ordinary character and graphic LCDs. The lcd display effect of white characters on a black background is sharp and has a strong contrast. It is usually used in displays that require high contrast and wide viewing angles, such as automotive instruments, medical equipment, and industrial control.
These are the reasons why we prefer VA products for negative lcd display. If the visual effect of the product is not high and cost control is desired, TN 7 segment lcd  are the best choice.