Multiplexed or Static Segmented LCDs – What is Best for Your Project
Segment displays remain one of the most popular LCD choices for new applications, even though it is one of the oldest display technologies. While most people think of OLEDs or TFTs when designing new mobile devices such as phones or tablets, segment displays are still a common choice for many applications that don’t require full video capabilities and can get by with a nominal amount of information. While most display technologies have pixels, segment LCDs have segments. A segment is any line, dot, or symbol that can be switched on and off individually.
A segmented LCD is an excellent choice for use cases that require a highly adjustable, low-power display. Segment LCDs, also known as static displays or glass-only displays, comprise two pieces of ITO (indium tin oxide) glass sandwiched between two layers of twisted nematic fluid. Other display technologies, such as TFT or OLEDs, require more power than segment displays. As a result, these LCDs are perfect for battery- or solar-powered applications. Thermostats, household appliances, medical equipment, industrial meters, and other goods commonly use segmented LCDs. Aside from low power consumption, segment LCDs offer some prime advantages, such as lower purchasing and design costs (tooling), rugged design and easy programming.
Segment LCDs remain one of the top choices for cost-sensitive projects. The main reason for this is that they usually do not contain a driver chip. When this is the case, there are two interface types – static and multiplex. They both share the same tooling costs. As a result, they are the top choice when pursuing projects in which numbers are displayed or a few simple icons such as battery indicators. You’ve probably been gazing at seven-segment numbers on numerous items for years and haven’t realized their universal and simple use. The adaptability of a seven-segment number is demonstrated by the simplicity with which individual segments of the character may be turned ON or OFF to generate any number from 0 to 9 and various letters.
If your project requires the highest possible visibility, contrast and viewings angles may be a key consideration. Static drive segment LCDs offer the best, sharpest contrast – this is because when a segment is on, it is being powered 100% of the time. This also results in the readability of the display being improved from different angles. So, if you are developing an outdoor application or perhaps a device that will require the LCD to be read from a distance, then a static drive display may be best due to the improved contrast.
Multiplexed displays are extremely common and are electrical display devices that do not drive the full display at once. Instead, sub-units of the display (typically, rows or columns for a dot matrix display or individual characters for a character-oriented display, occasionally individual display elements) are multiplexed or driven one at a time, but the electronics and the viewer’s persistence of vision combine to give the impression that the entire display is always active.
When compared to a non-multiplexed display, a multiplexed display offers various advantages: There are fewer pins (sometimes significantly fewer) that are required, which can save a few pennies on the LCD, but may also save costs on the MCU that is used by the customer. They also have reduced power consumption, and some consider the programming easier due to the lower pin count. The multiplex LCDs can also allow the LCD design to have a larger number of total segments on the design since there won’t have to be as many pins located around the edges of the glass. So, if you are developing an extremely low power device or require the least expensive option or have an MCU with very few pins available, it may be best to multiplex your LCD.
It’s no wonder that Segment LCDs are still a popular choice for low-cost applications. The lack of a controller/driver chip is the primary cause of this. There are two sorts of drive choices available: static and multiplex. The tooling expenses are the same for both. However, they are the best option for applications that require the display of numbers or a few basic icons. Depending on your use case, you can’t go wrong when choosing between multiplexed or static displays – and many choices are available at Focus LCDs to ensure your project is a success.