Segmented LCD screens can be positive (normal) display or negative display. In layman's terms, black text on a white background is positive display, while white text on a black background is negative display. We will not consider the color of the backlight LEDs. When using a segmented screen in normal display, the font color is black (for TN, HTN, STN yellow-green film) or blue (for STN, FSTN gray film); when using a segmented screen in negative display, the font color is white.

First, segmented screens display multiple colors by screen printing color on the bottom glass surface or bottom polarizer. We'll divide this into two cases.

Typically, when using segmented screens for positive display, most of them only use black screen printing (e.g. remote control screens) or red screen printing (e.g. heart rate display on treadmill screens).

However, the screen printing effect on positive displays is poor, as you can clearly see the screen printed colors when the segmented screen is not powered on.

Secondly, how many colors can be displayed when the segmented screen is in negative display?

For SINDA LCD displays, a single screen can display at most 5 colors - why not 6, 7 or more?

Let me briefly walk you through the screen printing process to understand this. For example, a negatively displayed segmented screen is printed with red, yellow, green, cyan, blue and purple. Then 5 screen printing screens (often called stencils) are made prior to screen printing, and red is screen printed first. If there are issues with screen printing mismatch, under-printing or over-printing during this process, erase and re-screen print until the requirements are met.

Then it is dried or baked in an oven to cure (not exceeding the LCD storage issue). After the screen dries, visually inspect if the screen meets the drawing requirements again. After printing the red screen, switch to the yellow screen stencil and start printing the yellow screen. The steps are the same as above.

If the screen printing is not good during the yellow screen printing process, all the previous red and yellow screen printing should be erased and restarted. What about those five colors? Therefore, the screen printing process is relatively complex and time-consuming, requiring strict handling. Usually, the segmented screen factory recommends using 3 or 4 colors for screen printing for customers, as this does not extend the production cycle, reduces the production scrap rate, and can increase the profit margin of the product.