Are you designing a device with a screen? It is a step in the right direction. Modern electronic devices are increasingly equipped with displays for aesthetic reasons and, most importantly, functionality. Today, the screen is more than just an element that presents data. It has become a key user interface, enabling intuitive control, instant response to system messages, and direct interaction with device functions.
In this guide, we present the most important issues to consider when choosing the optimal display for the solution you are designing. These issues almost always arise at the initial stage of cooperation – they help us better understand the needs of the end user and the specifics of the application in which our product is to be used.
Such a “technological interview” is not just a formality – it is the key to effective cooperation, which significantly speeds up the design process and avoids costly mistakes.
In this article, we discuss issues related to the external dimensions of modules, selecting the appropriate screen size, choosing a data transmission interface, and the importance of estimated annual usage (EAU) in the project planning and delivery process.
👉 Take a look at other articles in the series How to choose a display for your application?:
- part 1: technological basics and working environment,
- part 3: operation, durability, additional features.
External dimensions
It is worth starting the display selection with a practical question: how much space can the display module require? Knowing the exact dimensions of the space allocated for the screen makes it easier to choose the right solution and avoid installation problems.
External dimensions include not only the diagonal screen size but also the complete physical size of the entire module – including the frame, touch panel, protective glass, and control electronics. Proper fit eliminates the need for subsequent modifications to the housing design.
Knowing the device’s interior design also leads to better cable routing, connector placement, and cooling or heating systems planning. Although it may seem trivial, this parameter significantly impacts the design’s ergonomics, aesthetics, and reliability.
Size
The size of the display, expressed as its diagonal screen size in inches, affects the device’s overall dimensions. Still, the active area (AA) determines the actual space on which the content is presented. The appropriate size selection should consider both the installation conditions and the way the user interacts with the device.
In addition to standard rectangular formats, displays with non-standard shapes, such as square or circular, are also available. They are suitable for applications in which traditional proportions would be ineffective.
It is also worth considering panoramic formats, which are especially useful in passenger information systems. In these systems, a wide image increases readability and communication effectiveness.
Interface
The interface is a “language” needed for communication between the display and the rest of the system. Choosing the right data transmission interface is crucial at the device design stage. Each available interface has advantages and disadvantages, so matching it to the specific application, hardware requirements, and operating environment is essential.
One of the most commonly used interfaces is LVDS (Low-Voltage Differential Signaling), a solution with high transmission stability used in many LCD-TFTs, especially ones with larger diagonal screen sizes. LVDS distinguishes itself by fast data transfer with low electromagnetic interference, making it ideal for industrial, medical, and transportation applications.
With the development of technology, newer interfaces, such as HDMI, MIPI, and eDP, offer higher bandwidth or simplified cabling. If you want to learn more about the advantages and disadvantages of each type of image transmission, check out our interface guides: overview of popular interfaces – part 1 and overview of popular interfaces – part 2.
EAU – Estimated Annual Usage
When designing and implementing devices with display modules, one crucial parameter that should be considered at the beginning of cooperation with the supplier is EAU (Estimated Annual Usage), the estimated annual demand for a given component, most often expressed in the number of units.
The EAU is so important because it directly affects key elements of the entire supply chain:
- availability of components – knowing the approximate demand makes it possible to secure production batches from the supplier in advance – this is particularly important in the case of components with long lead times or those manufactured to order;
- supply stability – products with stable and predictable EAU are easier to incorporate into production schedules, which reduces the risk of downtime or delays;
- tailoring the solution – when the supplier knows the annual volume, it can propose appropriate technologies and cost-effective components also available in the long term (essential for projects with a life cycle of several years).
It is worth noting that EAU does not have to be a fixed number – an approximate estimate is sufficient to help with production and logistics planning.
👉 Take a look at other articles in the series How to choose a display for your application?:
